TY - JOUR A1 - Tiedemann, Ralph A1 - Schneider, Anja R. R. A1 - Havenstein, Katja A1 - Blanck, Torsten A1 - Meier, Elmar A1 - Raffel, Martina A1 - Zwartepoorte, Henk A1 - Plath, Martin T1 - New microsatellite markers allow high-resolution taxon delimitation in critically endangered Asian box turtles, genus Cuora JF - Salamandra : German journal of herpetology N2 - We isolated and characterized 16 new di- and tetranudeotide microsatellite markers for the critically endangered Asian box turtle genus Cuora, focusing on the "Cuora trifasciata" species complex. The new markers were then used to analyse genetic variability and divergence amongst five described species within this complex, namely C. aurocapitata (n = 18), C. cyclornata (n = 31), C. pani (n = 6), C. trifasciata (n = 58), and C. zhoui (n = 7). Our results support the view that all five species represent valid taxa. Within two species (C. trifasciata and C. cyclornata), two distinct morphotypes were corroborated by microsatellite divergence. For three individuals, morphologically identified as being of hybrid origin, the hybrid status was confirmed by our genetic analysis. Our results confirm the controversial species (Cuora aurocapitata, C. cyclornata) and subspecies/morphotypes (C. cyclornata meieri, C. trifasciata cf. trifasciata) to be genetically distinct, which has critical implications for conservation strategies. KW - Testudines KW - Cuora KW - box turtles KW - captive breeding KW - conservation units KW - microsatellites Y1 - 2014 SN - 0036-3375 VL - 50 IS - 3 SP - 139 EP - 146 PB - Deutsche Gesellschaft für Herpetologie und Terrarienkunde CY - Darmstadt ER - TY - THES A1 - Cao, Xianyong T1 - Vegetation and climate change in eastern continental Asia during the last 22 ka inferred from pollen data synthesis Y1 - 2014 ER - TY - THES A1 - Gaßmöller, René T1 - The interaction of subducted slabs and plume generation zones in geodynamic models Y1 - 2014 ER - TY - THES A1 - Feld, Christian T1 - Crustal structure of the Eratosthenes Seamount, Cyprus and S. Turkey from an amphibian wide-angle seismic profile T1 - Die Krustenstruktur von dem Eratosthenes Seeberg, Zypern und der Süd-Türkei anhand eines amphibischen seismischen Weitwinkel Profils N2 - In March 2010, the project CoCoCo (incipient COntinent-COntinent COllision) recorded a 650 km long amphibian N-S wide-angle seismic profile, extending from the Eratosthenes Seamount (ESM) across Cyprus and southern Turkey to the Anatolian plateau. The aim of the project is to reveal the impact of the transition from subduction to continent-continent collision of the African plate with the Cyprus-Anatolian plate. A visual quality check, frequency analysis and filtering were applied to the seismic data and reveal a good data quality. Subsequent first break picking, finite-differences ray tracing and inversion of the offshore wide-angle data leads to a first-arrival tomographic model. This model reveals (1) P-wave velocities lower than 6.5 km/s in the crust, (2) a variable crustal thickness of about 28 - 37 km and (3) an upper crustal reflection at 5 km depth beneath the ESM. Two land shots on Turkey, also recorded on Cyprus, airgun shots south of Cyprus and geological and previous seismic investigations provide the information to derive a layered velocity model beneath the Anatolian plateau and for the ophiolite complex on Cyprus. The analysis of the reflections provides evidence for a north-dipping plate subducting beneath Cyprus. The main features of this layered velocity model are (1) an upper and lower crust with large lateral changes of the velocity structure and thickness, (2) a Moho depth of about 38 - 45 km beneath the Anatolian plateau, (3) a shallow north-dipping subducting plate below Cyprus with an increasing dip and (4) a typical ophiolite sequence on Cyprus with a total thickness of about 12 km. The offshore-onshore seismic data complete and improve the information about the velocity structure beneath Cyprus and the deeper part of the offshore tomographic model. Thus, the wide-angle seismic data provide detailed insights into the 2-D geometry and velocity structures of the uplifted and overriding Cyprus-Anatolian plate. Subsequent gravity modelling confirms and extends the crustal P-wave velocity model. The deeper part of the subducting plate is constrained by the gravity data and has a dip angle of ~ 28°. Finally, an integrated analysis of the geophysical and geological information allows a comprehensive interpretation of the crustal structure related to the collision process. N2 - Im März 2010 wurden im Rahmen des "CoCoCo"-Projektes ein 650km langes amphibisches, seismisches Weitwinkel Profil aufgenommen. Dieses erstreckte sich von dem Eratosthenes Seeberg (ESM) über Zypern und der Süd-Türkei bis zum anatolischen Plateau. Das Hauptziel des Projektes ist es, den Einfluss zu untersuchen, der von dem Übergang eines Subduktion Prozesses hin zu einer Kontinent-Kontinent Kollision der afrikanischen Platte mit der zyprisch-anatolischen Platte hervorgerufen wird. Die seismischen Daten wurden einer visuelle Qualitätsüberprüfung, Frequenz-Analyse und Filterung unterzogen und zeigten eine gute Qualität. Das darauf folgende Picken der Ersteinstätze, eine Finite-Differenzen Raytracing und eine Inversion der offshore Weitwinkel Daten, führte zu einem Laufzeit Tomographie Model. Das Modell zeigt (1) P-Wellengeschwindigkeiten kleiner als 6.5 km/s in der Kruste, (2) eine variable Krustenmächtigkeit von 28 - 37 km und (3) eine obere Krustenreflektion in 5 km Tiefe unter dem ESM. Zwei Landschüsse in der Türkei, ebenfalls aufgenommen auf Zypern, Luftkanonen-Schüsse südlich von Zypern und vorausgegangene geologische und seismische Untersuchungen lieferten die Grundlage, um ein geschichtetes Geschwindigkeitsmodell für das anatolische Plateau und für den Ophiolith-Komplex auf Zypern abzuleiten. Die Analyse der Reflexionen liefert den Beweis für eine nach Norden einfallende Platte welche unter Zypern subduziert. Die Hauptkennzeichen dieses geschichteten Geschwindigkeitsmodelles sind (1) eine obere und untere Kruste mit starken lateral Änderungen in Geschwindigkeit und Mächtigkeit, (2) eine Mohotiefe in 38 - 45 km unter dem anatolischen Plateau, (3) eine flach nach Norden einfallende Platte unter Zypern mit ansteigendem Einfallwinkel und (4) eine typische Ophiolith Sequenz auf Zypern mit einer Gesamtmächtigkeit von 12 km. Die seismischen offshore / onshore Daten komplettieren und verbessern die bisherigen Kenntnisse über die Geschwindigkeitsstruktur unter Zypern und des tieferen Bereiches der offshore Tomographie. Damit liefert die Weitwinkel Seismik detaillierte Einblicke in die 2-D Geometrie und die Geschwindigkeitsstrukturen der angehobenen und überlagerten zyprisch-anatolischen Platte. Die darauf folgende Gravimetrie Modellierung bestätigt und erweitert das P-Wellen Krusten-Geschwindigkeits Modell. Der tiefere Teil der subduzierten Platte, welche einen Einfallswinkel von ~ 28° hat, wurde durch die Gravimetrie Daten belegt. Letztlich erlaubt eine ganzheitliche Analyse von geophysikalischen und geologischen Informationen die umfassende Interpretation der Krustenstruktur welche in Verbindung mit dem Kollisions Prozess steht. KW - incipient continent-continent collision KW - crustal structure of the Eratosthenes Seamount KW - controlled source wide angle seismic KW - crustal structure of south central Turkey KW - Cyprus arc KW - aktive Weitewinkel-Seismik KW - Krustenstruktur des Eratosthenes Seeberges KW - beginnende Kontinent-Kontinent Kollision KW - Krustenstruktur der Süd-Türkei KW - Zypernbogen Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-73479 ER - TY - THES A1 - Tympel, Jens Günter T1 - Numerical modeling of the Cenozoic Pamir-Tien Shan orogeny Y1 - 2014 ER - TY - THES A1 - Borchardt, Sven T1 - Rainfall, weathering and erosion BT - quantification of earth surface processes in Suguta Valley, northern Kenya, using multispectral and hyperspectral data Y1 - 2014 ER - TY - THES A1 - Pussak, Marcin T1 - Seismic characterization of geothermal reservoirs by application of the common-reflection-surface stack method and attribute analysis T1 - Seismische Charakterisierung von geothermischen Reservoiren mittels “Common-Reflection-Surface” Stapelungs-Methode und Attribut-Analysen N2 - An important contribution of geosciences to the renewable energy production portfolio is the exploration and utilization of geothermal resources. For the development of a geothermal project at great depths a detailed geological and geophysical exploration program is required in the first phase. With the help of active seismic methods high-resolution images of the geothermal reservoir can be delivered. This allows potential transport routes for fluids to be identified as well as regions with high potential of heat extraction to be mapped, which indicates favorable conditions for geothermal exploitation. The presented work investigates the extent to which an improved characterization of geothermal reservoirs can be achieved with the new methods of seismic data processing. The summations of traces (stacking) is a crucial step in the processing of seismic reflection data. The common-reflection-surface (CRS) stacking method can be applied as an alternative for the conventional normal moveout (NMO) or the dip moveout (DMO) stack. The advantages of the CRS stack beside an automatic determination of stacking operator parameters include an adequate imaging of arbitrarily curved geological boundaries, and a significant increase in signal-to-noise (S/N) ratio by stacking far more traces than used in a conventional stack. A major innovation I have shown in this work is that the quality of signal attributes that characterize the seismic images can be significantly improved by this modified type of stacking in particular. Imporoved attribute analysis facilitates the interpretation of seismic images and plays a significant role in the characterization of reservoirs. Variations of lithological and petro-physical properties are reflected by fluctuations of specific signal attributes (eg. frequency or amplitude characteristics). Its further interpretation can provide quality assessment of the geothermal reservoir with respect to the capacity of fluids within a hydrological system that can be extracted and utilized. The proposed methodological approach is demonstrated on the basis on two case studies. In the first example, I analyzed a series of 2D seismic profile sections through the Alberta sedimentary basin on the eastern edge of the Canadian Rocky Mountains. In the second application, a 3D seismic volume is characterized in the surroundings of a geothermal borehole, located in the central part of the Polish basin. Both sites were investigated with the modified and improved stacking attribute analyses. The results provide recommendations for the planning of future geothermal plants in both study areas. N2 - Ein wichtiger Beitrag der Geowissenschaften zur Bereitstellung erneuerbarer Energien besteht in der Nutzbarmachung von geothermischen Ressourcen. Für die Entwicklung von geothermischen Anlagen in großen Tiefen ist in der ersten Phase eine detaillierte geologisch-geophysikalische Erkundung erforderlich. Hierbei werden Informationen über das Temperaturfeld, zur Litho-Stratigraphie und Strukturgeologie, Geomechanik, Hydrogeologie sowie petrophysikalische Eigenschaften im Reservoir-Maßstab benötigt. Mit Hilfe aktiver seismischer Methoden können hochauflösende Abbilder des geothermischen Reservoirs geliefert werden. Dadurch können potentielle Transportwege für Fluide sowie Regionen mit hohem Wärmeabsorptionspotential identifiziert und kartiert werden. Die vorgelegte Arbeit untersucht, inwieweit mit neuen Methoden der seismischen Datenbearbeitung eine verbesserte Charakterisierung von geothermischen Reservoiren erreicht werden kann. Die Stapelung ist ein entscheidender Schritt bei der Bearbeitung von seismischen Felddaten. Die sogenannte “common-reflection-surface” Stapelung ist eine Erweiterung des klassischen Stapelungs-Konzepts. Durch ihre Anwendung können detailliertere und zuverlässigere Abbilder des Untergrundes gewonnen werden. Als wichtige Neuerung habe ich in der Arbeit aufgezeigt, dass durch diese modifizierte Art der Stapelung insbesondere die Qualität von Signalattribut-Darstellungen der seismischen Abbilder signifikant verbessert wird. Signalattribute sind ein wichtiges Werkzeug bei der Untersuchung von Reservoiren. Variationen der lithologischen und petrophysikalischen Eigenschaften spiegeln sich in Variationen in bestimmten Signalattributen (z.B. Frequenzeigenschaften, Amplitudeneigenschaften) wieder. Daraus kann auf die Qualität des geothermischen Reservoirs, z.B. hinsichtlich der Aufnahmefähigkeit von Fluiden zur Wärmeabsorption in Kreislaufsystemen, geschlossen werden. Das vorgeschlagenen methodische Konzept wird an Hand von 2 Fallstudien demonstriert. Im ersten Beispiel analysierte ich eine Reihe von 2D seismischen Profilschnitten durch das Alberta-Sedimentbecken am Ostrand der kanadischen Rocky Mountains. Bei der zweiten Anwendung wird ein 3D seismisches Volumen im Umfeld einer Geothermie-Bohrung im Zentralteil des Polnischen Sedimentbeckens mit Hilfe der modifizierten Stapelung und verbesserten Attribut-Analysen charakterisiert. Die Ergebnisse ermöglichen Empfehlungen für die Planung zukünftiger Geothermie-Anlagen in beiden Untersuchungsgebieten. KW - seismic KW - geothermischer Reservoire KW - seismische Stapelungs-Methode KW - Attribut-Analysen KW - Verarbeitung seismischer Daten KW - Common-Reflection-Surface Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-77565 ER - TY - THES A1 - Muksin, Umar T1 - A fault-controlled geothermal system in Tarutung (North Sumatra, Indonesia)investigated by seismological analysis N2 - The seismic structure (Vp, Vp/Vs, and Qp anomalies) contributes to the physical properties and the lithology of rocks and possible fluid distribution in the region. The Vp model images the geometry of the Tarutung and the Sarulla basins. Both basins have a depth of around 2.0 km. High Vp/Vs and high attenuation (low Qp) anomalies are observed along the Sarulla graben associated with a weak zone caused by volcanic activities along the graben. Low Vp/Vs and low conductivity anomalies are found in the west of the Tarutung basin. This anomaly is interpreted as dry, compact, and rigid granitic rock in the region as also found by geological observations. Low Vp, high Vp/Vs and low Qp anomalies are found at the east of the Tarutung basin which appear to be associated with the three big geothermal manifestations in Sipoholon, Hutabarat, and Panabungan area. These anomalies are connected with high Vp/Vs and low Qp anomalies below the Tarutung basin at depth of around 3 - 10 km. This suggests that these geothermal manifestations are fed by the same source of the hot fluid below the Tarutung basin. The hot fluids from below the Tarutung basin propagate to the more dilatational and more permeable zone in the northeast. Granite found in the west of the Tarutung basin could also be abundant underneath the basin at a certain depth so that it prevents the hot fluid to be transported directly to the Tarutung basin. High seismic attenuation and low Vp/Vs anomalies are found in the southwest of the Tarutung basin below the Martimbang volcano. These anomalies are associated with hot rock below the volcano without or with less amount of partial melting. There is no indication that the volcano controls the geothermal system around the Tarutung basin. The geothermal resources around the Tarutung basin is a fault-controlled system as a result of deep circulation of fluids. Outside of the basin, the seismicity delineation and the focal mechanism correlate with the shape and the characteristics of the strike-slip Sumatran fault. Within the Tarutung basin, the seismicity is distributed more broadly which coincides with the margin of the basin. An extensional duplex system in the Tarutung basin is derived from the seismicity and focal mechanism analysis which is also consistent with the geological observations. The vertical distribution of the seismicity suggests the presence of a negative flower structure within the Tarutung basin. N2 - Indonesien zählt zu den weltweit führenden Ländern bei der Nutzung von geothermischer Energie. Die geothermischen Energiequellen sind im Wesentlichen an den aktiven Vulkanismus gebunden, der durch die Prozesse an der indonesischen Subduktionszone verursacht wird. Darüber hinaus sind geotektonische Strukturen wie beispielsweise die Sumatra-Störung als verstärkende Faktoren für das geothermische Potenzial von Bedeutung. Bei der geophysikalischen Erkundung der indonesischen Geothermie-Ressourcen konzentrierte man sich bisher vor allem auf die Magnetotellurik. Passive Seismologie wurde dahingegen ausschließlich für die Überwachung von im Betrieb befindlichen Geothermie-Anlagen verwendet. Jüngste Untersuchungungen z.B. in Island und in den USA haben jedoch gezeigt, dass seismologische Verfahren bereits in der Erkundungsphase wichtige Informationen zu den physikalischen Eigenschaften, zum Spannungsfeld und zu möglichen Fluid- und Wärmetransportwegen liefern können. In der vorgelegten Doktorarbeit werden verschiedene moderne Methoden der passiven Seismologie verwendet, um beispielhaft ein neues, von der indonesischen Regierung für zukünftige geothermische Energiegewinnung ausgewiesenes Gebiet im nördlichen Teil Sumatras (Indonesien) zu erkunden. Die konkreten Ziele der Untersuchungen umfassten (1) die Ableitung von 3D Strukturmodellen der P- und S-Wellen Geschwindigkeiten (Parameter Vp und Vs), (2) die Bestimmung der Absorptionseigenschaften (Parameter Qp), und (3) die Kartierung und Charakterisierung von Störungssystemen auf der Grundlage der Seismizitätsverteilung und der Herdflächenlösungen. Für diese Zwecke habe ich zusammen mit Kollegen ein seismologisches Netzwerk in Tarutung (Sumatra) aufgebaut und über einen Zeitraum von 10 Monaten (Mai 2011 – Februar 2012) betrieben. Insgesamt wurden hierbei 42 Stationen (jeweils ausgestattet mit EDL-Datenlogger, 3-Komponenten, 1 Hz Seismometer) über eine Fläche von etwa 35 x 35 km verteilt. Mit dem Netzwerk wurden im gesamten Zeitraum 2568 lokale Erdbeben registriert. Die integrierte Betrachtung der Ergebnisse aus den verschiedenen Teilstudien (Tomographie, Erdbebenverteilung) erlaubt neue Einblicke in die generelle geologische Stukturierung sowie eine Eingrenzung von Bereichen mit einem erhöhten geothermischen Potenzial. Das tomographische Vp-Modell ermöglicht eine Bestimmung der Geometrie von Sedimentbecken entlang der Sumatra-Störung. Für die Geothermie besonders interessant ist der Bereich nordwestlich des Tarutung-Beckens. Die dort abgebildeten Anomalien (erhöhtes Vp/Vs, geringes Qp) habe ich als mögliche Aufstiegswege von warmen Fluiden interpretiert. Die scheinbar asymetrische Verteilung der Anomalien wird hierbei im Zusammenhang mit der Seismizitätsverteilung, der Geometrie der Beben-Bruchflächen, sowie struktur-geologischen Modellvorstellungen diskutiert. Damit werden wesentliche Informationen für die Planung einer zukünftigen geothermischen Anlage bereitgestellt. T2 - Seismologische Untersuchungen eines Störungs-kontrollierten geothermischen Systems in Tarutung (Nord-Sumatra, Indonesien) KW - Tarutung KW - Sumatra Störung KW - Absorptionseigenschaften KW - seismische Geschwindigkeiten KW - Tarutung KW - Sumatra fault KW - attenuation tomography KW - velocity structure Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-72065 ER - TY - THES A1 - Schollaen, Karina T1 - Tracking climate signals in tropical trees T1 - Klimasignale in tropischen Hölzern BT - new insights from Indonesian stable isotope records BT - neue Erkenntnisse von stabilen Isotopendaten aus Indonesien N2 - The tropical warm pool waters surrounding Indonesia are one of the equatorial heat and moisture sources that are considered as a driving force of the global climate system. The climate in Indonesia is dominated by the equatorial monsoon system, and has been linked to El Niño-Southern Oscillation (ENSO) events, which often result in severe droughts or floods over Indonesia with profound societal and economic impacts on the populations living in the world's fourth most populated country. The latest IPCC report states that ENSO will remain the dominant mode in the tropical Pacific with global effects in the 21st century and ENSO-related precipitation extremes will intensify. However, no common agreement exists among climate simulation models for projected change in ENSO and the Australian-Indonesian Monsoon. Exploring high-resolution palaeoclimate archives, like tree rings or varved lake sediments, provide insights into the natural climate variability of the past, and thus helps improving and validating simulations of future climate changes. Centennial tree-ring stable isotope records | Within this doctoral thesis the main goal was to explore the potential of tropical tree rings to record climate signals and to use them as palaeoclimate proxies. In detail, stable carbon (δ13C) and oxygen (δ18O) isotopes were extracted from teak trees in order to establish the first well-replicated centennial (AD 1900-2007) stable isotope records for Java, Indonesia. Furthermore, different climatic variables were tested whether they show significant correlation with tree-ring proxies (ring-width, δ13C, δ18O). Moreover, highly resolved intra-annual oxygen isotope data were established to assess the transfer of the seasonal precipitation signal into the tree rings. Finally, the established oxygen isotope record was used to reveal possible correlations with ENSO events. Methodological achievements | A second goal of this thesis was to assess the applicability of novel techniques which facilitate and optimize high-resolution and high-throughput stable isotope analysis of tree rings. Two different UV-laser-based microscopic dissection systems were evaluated as a novel sampling tool for high-resolution stable isotope analysis. Furthermore, an improved procedure of tree-ring dissection from thin cellulose laths for stable isotope analysis was designed. The most important findings of this thesis are: I) The herein presented novel sampling techniques improve stable isotope analyses for tree-ring studies in terms of precision, efficiency and quality. The UV-laser-based microdissection serve as a valuable tool for sampling plant tissue at ultrahigh-resolution and for unprecedented precision. II) A guideline for a modified method of cellulose extraction from wholewood cross-sections and subsequent tree-ring dissection was established. The novel technique optimizes the stable isotope analysis process in two ways: faster and high-throughput cellulose extraction and precise tree-ring separation at annual to high-resolution scale. III) The centennial tree-ring stable isotope records reveal significant correlation with regional precipitation. High-resolution stable oxygen values, furthermore, allow distinguishing between dry and rainy season rainfall. IV) The δ18O record reveals significant correlation with different ENSO flavors and demonstrates the importance of considering ENSO flavors when interpreting palaeoclimatic data in the tropics. The findings of my dissertation show that seasonally resolved δ18O records from Indonesian teak trees are a valuable proxy for multi-centennial reconstructions of regional precipitation variability (monsoon signals) and large-scale ocean-atmosphere phenomena (ENSO) for the Indo-Pacific region. Furthermore, the novel methodological achievements offer many unexplored avenues for multidisciplinary research in high-resolution palaeoclimatology. N2 - Die tropischen Gewässer um Indonesien sind eine der äquatorialen Wärme- und Feuchtigkeitsquellen, die als treibende Kraft des globalen Klimasystems betrachtet werden können. Das Klima in Indonesien ist geprägt durch das Australisch-Indonesische Monsunsystem. Weiterhin besteht eine Verknüpfung mit El Niño-Southern Oszillation (ENSO) Ereignissen, die oft zu schweren Dürren oder Überschwemmungen in der Region mit tiefgreifenden gesellschaftlichen und wirtschaftlichen Folgen führen. Der neueste IPCC-Bericht legt dar, dass ENSO auch in den nächsten 100 Jahren das vorherrschende Klimaphänomen im tropischen Pazifik bleiben wird. Ferner wird davon ausgegangen, dass sich die ENSO-bezogenen Niederschlagsextrema intensivieren werden. Wenig Übereinstimmung herrscht jedoch bislang zwischen den Klimasimulationsmodellen in Bezug auf die voraussichtlichen Veränderungen von ENSO und dem Australisch-Indonesischen Monsunsystem. Hochaufgelöste Paläoklima-Archive, wie z.B. Jahrringe oder warvierte Seesedimente, geben Auskunft über die natürliche Klimavariabilität der Vergangenheit und können somit dazu beitragen, die Computersimulationen der künftigen Klimaentwicklung zu verbessern und zu validieren. Hundertjährige stabile Jahrring-Isotopenchronologien | Das Hauptziel dieser Doktorarbeit war es, dass Potenzial von tropischen Jahrringen zur Aufzeichnung von Klimasignalen herauszustellen und deren Evaluierung als Paläoklimaproxys. Im Detail wurden stabile Kohlenstoff- (δ13C) und Sauerstoff- (δ18O) Isotopenverhältnisse in Teakbäumen analysiert, und die ersten gut replizierten hundertjährigen (AD 1900-2007) stabilen Isotopenchronologien aus Java (Indonesien) erstellt. Dabei wurden verschiedene klimatische Einflussgrößen getestet, ob diese signifikante Korrelationen mit den Jahrringparametern aufzeigen. Weiterhin wurden hochaufgelöste intra-annuelle Sauerstoffisotopenzeitreihen erstellt, um den Transfer des saisonalen Niederschlagssignals in den jeweiligen Jahrring zu bemessen. Die ermittelte Sauerstoff-Isotopenchronologie wurde anschließend auf mögliche ENSO Signale hin untersucht. Methodische Errungenschaften | Ein zweites Ziel dieser Arbeit war es neue Verfahren zur Analyse stabiler Isotope in Baumjahrringen zu entwickeln und zu optimieren. Zwei verschiedene UV-Lasermikrodissektions-Systeme wurden getestet als neues präzises Präparationswerkzeug für stabile Isotopenstudien. Darüber hinaus wurde eine verbesserte Methode für die Probenaufbereitung stabiler Isotopenmessungen anhand von Zellulose-Dünnschnitten entwickelt. Die wichtigsten Ergebnisse dieser Doktorarbeit sind: I) Die hier vorgestellten neuartigen Techniken zu Probenvorbereitung verbessern die Analyse stabiler Isotope für Jahrringstudien in Hinsicht auf Präzision, Effizienz und Qualität. Es wurde gezeigt, dass die UV-Lasermikrodissektion eine wertvolle Technik ist, um die Beprobung von Pflanzengewebe in höchster Auflösung und beispielloser Präzision durchzuführen. II) Es ist gelungen, einen Leitfaden für ein modifiziertes Verfahren der Zelluloseextraktion an Gesamtholz-Dünnschnitten und der anschließenden Jahrringaufbereitung zu erstellen. Diese neuartige Methode optimiert die Analyse stabiler Isotopenzeitreihen in zweierlei Hinsicht: schnellere und effiziente Zelluloseextraktion und präzise Trennung der Jahrringsequenzen in inter-annueller bis intra-annuelle Auflösung. III) Die hundertjährigen stabilen Jahrring-Isotopenchronologien weisen signifikante Korrelationen mit dem regionalen Niederschlag auf. In den hochaufgelösten stabilen Sauerstoffisotopenwerten spiegelt sich deutlich das Niederschlagssignal der Trocken- und der Regenzeit wieder. IV) Die stabile Sauerstoffisotopenzeitreihe zeigt signifikante Korrelationen mit verschiedenen ENSO Phasen. Dies betont, dass die verschiedenen ENSO Phasen bei der Interpretation von tropischen Paläodaten zu berücksichtigen sind. Die Ergebnisse der Dissertation zeigen, dass saisonal aufgelöste stabile Sauerstoffisotopenchronologien von indonesischen Teakbäumen ein geeigneter Proxy für mehrhundertjährige Rekonstruktionen der regionalen Niederschlagsvariabilität (Monsun-Signale) und großräumiger Ozean-Atmosphären-Systeme (ENSO) für den Indopazifik ist. Darüber hinaus bieten die neuartigen methodischen Errungenschaften viele neue Ansätze für multidisziplinäre hochaufgelöste Studien in der paläoklimatologischen Forschung. KW - Stabile Sauerstoff- und Kohlenstoffisotope KW - Dendroklimatologie KW - Tectona grandis KW - Tropen KW - UV-Lasermikrodissektion KW - oxygen and carbon stable isotopes KW - dendroclimatology KW - Tectona grandis KW - tropics KW - UV-laser microdissection Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-71947 ER - TY - THES A1 - Radeff, Giuditta T1 - Geohistory of the Central Anatolian Plateau southern margin (southern Turkey) T1 - Die geologische Entwicklung des südlichen zentralsanatolischen Plateaurandes (Süd-Türkei) N2 - The Adana Basin of southern Turkey, situated at the SE margin of the Central Anatolian Plateau is ideally located to record Neogene topographic and tectonic changes in the easternmost Mediterranean realm. Using industry seismic reflection data we correlate 34 seismic profiles with corresponding exposed units in the Adana Basin. The time-depth conversion of the interpreted seismic profiles allows us to reconstruct the subsidence curve of the Adana Basin and to outline the occurrence of a major increase in both subsidence and sedimentation rates at 5.45 – 5.33 Ma, leading to the deposition of almost 1500 km3 of conglomerates and marls. Our provenance analysis of the conglomerates reveals that most of the sediment is derived from and north of the SE margin of the Central Anatolian Plateau. A comparison of these results with the composition of recent conglomerates and the present drainage basins indicates major changes between late Messinian and present-day source areas. We suggest that these changes in source areas result of uplift and ensuing erosion of the SE margin of the plateau. This hypothesis is supported by the comparison of the Adana Basin subsidence curve with the subsidence curve of the Mut Basin, a mainly Neogene basin located on top of the Central Anatolian Plateau southern margin, showing that the Adana Basin subsidence event is coeval with an uplift episode of the plateau southern margin. The collection of several fault measurements in the Adana region show different deformation styles for the NW and SE margins of the Adana Basin. The weakly seismic NW portion of the basin is characterized by extensional and transtensional structures cutting Neogene deposits, likely accomodating the differential uplift occurring between the basin and the SE margin of the plateau. We interpret the tectonic evolution of the southern flank of the Central Anatolian Plateau and the coeval subsidence and sedimentation in the Adana Basin to be related to deep lithospheric processes, particularly lithospheric delamination and slab break-off. N2 - Il Bacino di Adana (Turchia meridionale) é situato in posizione esterna rispetto al margine sud-orientale del plateau anatolico centrale. Il bacino risulta ubicato in posizione strategica per registrare i principali cambiamenti della topografia e dell’assetto tettonico avvenuti durante il Neogene nel Mediterraneo orientale. Utilizzando dati sismici provenienti dall’industria petrolifera abbiamo correlato 34 profili sismici con le unitá corrispondenti affioranti nel Bacino di Adana. La conversione da tempi a profonditá dei profili sismici interpretati ci ha permesso di ricostruire la curva di subsidenza del Bacino di Adana e di individuare un evento caratterizato da un importante aumento della subsidenza associato ad un considerevole incremento del tasso di sedimentazione. Questo evento, avvenuto tra 5.45 e 5.33 Ma ha portato alla deposizione di quasi 1500 km3 di conglomerati e marne. La nostra analisi di provenienza della porzione conglomeratica mostra che la maggior parte del sedimento proviene dal margine sud-orientale del plateau anatolico centrale e dalle aree situate a nord di questo. La comparazione di questi risultati con la composizione litologica di conglomerati recenti e con le litologie affioranti nei bacini di drenaggio attuali mostra cambiamenti rilevanti tra le aree di provenienza del sedimento Messiniane e quelle attuali. Riteniamo che questi cambiamenti nelle aree sorgente siano il risultato del sollevamento e della successiva erosione del margine sud-orientale del plateau anatolico centrale. Questa ipotesi é supportata dal confronto delle curve di subsidenza del Bacino di Adana e del Bacino di Mut, un bacino principalmente neogenico situato sulla sommitá del margine meridionale del plateau. La comparazione delle due curve di subsidenza mostra che l’evento di forte subsidenza del Bacino di Adana é coevo ad un episodio di sollevamento del margine meridionale del plateau anatolico centrale. La raccolta di un fitto dataset strutturale acquisito nella regione di Adana mostra differenti stili deformativi per i margini nord-occidentale e sud-orientale del bacino. La porzione nord-occidentale del bacino, debolmente sismica, é caratterizzata da strutture estensionali e transtensive che tagliano I depositi neogenici, verosimilmente accomodando il sollevamento differenziale tra il bacino e il margine sud-orientale del plateau. Riteniamo che l’evoluzione tettonica del margine meridionale del plateau anatolico centrale e la contemporanea subsidenza e sedimentazione nel Bacino di Adana sia da ricondurre a processi litosferici profondi, in particolar modo delaminazione litosferica e slab break-off. KW - Hebung des Plateaus KW - Sedimentenabfolge KW - Subsidenzgeschichte KW - Adana Becken KW - Süd-Türkei KW - plateau uplift KW - sedimentary record KW - subsidence history KW - Adana Basin KW - southern Turkey Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-71865 ER - TY - JOUR A1 - Schaefer, Kevin A1 - Lantuit, Hugues A1 - Romanovsky, Vladimir E. A1 - Schuur, Edward A. G. A1 - Witt, Ronald T1 - The impact of the permafrost carbon feedback on global climate JF - Environmental research letters N2 - Degrading permafrost can alter ecosystems, damage infrastructure, and release enough carbon dioxide (CO2) and methane (CH4) to influence global climate. The permafrost carbon feedback (PCF) is the amplification of surface warming due to CO2 and CH4 emissions from thawing permafrost. An analysis of available estimates PCF strength and timing indicate 120 +/- 85 Gt of carbon emissions from thawing permafrost by 2100. This is equivalent to 5.7 +/- 4.0% of total anthropogenic emissions for the Intergovernmental Panel on Climate Change (IPCC) representative concentration pathway (RCP) 8.5 scenario and would increase global temperatures by 0.29 +/- 0.21 degrees C or 7.8 +/- 5.7%. For RCP4.5, the scenario closest to the 2 degrees C warming target for the climate change treaty, the range of cumulative emissions in 2100 from thawing permafrost decreases to between 27 and 100 Gt C with temperature increases between 0.05 and 0.15 degrees C, but the relative fraction of permafrost to total emissions increases to between 3% and 11%. Any substantial warming results in a committed, long-term carbon release from thawing permafrost with 60% of emissions occurring after 2100, indicating that not accounting for permafrost emissions risks overshooting the 2 degrees C warming target. Climate projections in the IPCC Fifth Assessment Report (AR5), and any emissions targets based on those projections, do not adequately account for emissions from thawing permafrost and the effects of the PCF on global climate. We recommend the IPCC commission a special assessment focusing on the PCF and its impact on global climate to supplement the AR5 in support of treaty negotiation. KW - permafrost carbon feedback KW - permafrost KW - global climate Y1 - 2014 U6 - https://doi.org/10.1088/1748-9326/9/8/085003 SN - 1748-9326 VL - 9 IS - 8 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Martinez-Garzon, Patricia A1 - Kwiatek, Grzegorz A1 - Sone, Hiroki A1 - Bohnhoff, Marco A1 - Dresen, Georg A1 - Hartline, Craig T1 - Spatiotemporal changes, faulting regimes, and source parameters of induced seismicity: A case study from the Geysers geothermal field JF - Journal of geophysical research : Solid earth N2 - The spatiotemporal, kinematic, and source characteristics of induced seismicity occurring at different fluid injection rates are investigated to determine the predominant physical mechanisms responsible for induced seismicity at the northwestern part of The Geysers geothermal field, California. We analyze a relocated hypocenter catalog from a seismicity cluster where significant variations of the stress tensor orientation were previously observed to correlate with injection rates. We find that these stress tensor orientation changes may be related to increased pore pressure and the corresponding changes in poroelastic stresses at reservoir depth. Seismic events during peak injections tend to occur at greater distances from the injection well, preferentially trending parallel to the maximum horizontal stress direction. In contrast, at lower injection rates the seismicity tends to align in a different direction which suggests the presence of a local fault. During peak injection intervals, the relative contribution of strike-slip faulting mechanisms increases. Furthermore, increases in fluid injection rates also coincide with a decrease in b values. Our observations suggest that regardless of the injection stage, most of the induced seismicity results from thermal fracturing of the reservoir rock. However, during peak injection intervals, the increase in pore pressure may likewise be responsible for the induced seismicity. By estimating the thermal and hydraulic diffusivities of the reservoir, we confirm that the characteristic diffusion length for pore pressure is much greater than the corresponding length scale for temperature and also more consistent with the spatial extent of seismicity observed during different injection rates. KW - thermal effect KW - focal mechanisms KW - geothermal KW - pore pressure KW - fluid-induced seismicity KW - reservoir characterization Y1 - 2014 U6 - https://doi.org/10.1002/2014JB011385 SN - 2169-9313 SN - 2169-9356 VL - 119 IS - 11 SP - 8378 EP - 8396 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Korup, Oliver A1 - Hayakawa, Yuichi A1 - Codilean, Alexandru T. A1 - Matsushi, Yuki A1 - Saito, Hitoshi A1 - Oguchi, Takashi A1 - Matsuzaki, Hiroyuki T1 - Japan's sediment flux to the Pacific Ocean revisited JF - Earth science reviews : the international geological journal bridging the gap between research articles and textbooks N2 - Quantifying volumes and rates of delivery of terrestrial sediment from island arcs to subduction zones is indispensable for refining estimates of the thickness of trench fills that may eventually control the location and timing of submarine landslides and tsunami-generating mega-earthquakes. Despite these motivating insights, knowledge about the rates of erosion and sediment export from the Japanese islands to their Pacific subduction zones remains patchy regardless of the increasing availability of highly resolved data on surface deformation, climate, geology, and topography. Traditionally, natural erosion rates across the island arc have been estimated from regression of topographic catchment metrics and reservoir sedimentation rates that were recorded over several years to decades. We review current research in this context, correct for a systematic bias in one of the most widely used predictions, and present new estimates of decadal to millennial-scale erosion rates of Japan's terrestrial inner forearc. We draw on several independent and unprecedented inventories of mass wasting, reservoir sedimentation, and concentrations of cosmogenic Be-10 in river sands. We find that natural Be-10-derived denudation rates of several mm yr(-1) in the Japanese Alps have been sustained over several centuries to millennia, and are, within error, roughly consistent with sediment yields inferred from artificial reservoir sedimentation. Local exceptions may likely result from release of sediment storage or regional landsliding episodes that trigger transient sediment pulses. Our synopsis further reveals that catchments draining Japan's eastern seaboard differ distinctly in their tectonic, lithological, topographic, and climatic characteristics between the Tohoku, Japanese Alps, and Nankai inner forearc segments, which is underscored by a marked asymmetric pattern of erosion rates along the island arc. Erosion rates are highest (up to at least 3 mm yr(-1)) in the Japanese Alps that mark the collision of two subduction zones, where high topographic relief, hillslope and bedrock-channel steepness foster rapid denudation by mass wasting. Comparable, if slightly lower, erosion rates characterise the Nankai inner forearc in southwest Japan, most likely due to higher typhoon-driven rainfall totals and variability rather than its high topographic relief. In contrast, our estimated erosion and flux rates are lowest in the Tohoku inner forearc catchments that feed sediment into the Japan Trench. We conclude that collisional mountain building of the Japanese Alps drives some of the highest erosion rates in the island arc despite similar uplift and precipitation controls in southwest Japan. We infer that, prior to extensive river damming, reservoir construction, and coastal works, the gross of Japan's total sediment export to the Pacific Ocean entered the accretionary margin of the Nankai Trough as opposed to the comparatively sediment-starved Japan Trench. Compared to documented contemporary rates of sediment flux from mountainous catchments elsewhere in the Pacific, the rivers draining Japan's inner forearc take an intermediate position despite high relief, steep slopes, very high seismicity, and frequent rainstorms. However, the average rates of millennial-scale denudation in the Japanese Alps particularly are amongst the highest reported worldwide. Local mismatches between these late Holocene and modern rates emphasise the anthropogenic fingerprint on sediment retention that may have significantly reduced the island arc's mass flux to its subduction zones, as is the case elsewhere in east and southeast Asia. (C) 2014 Elsevier B.V. All rights reserved. KW - Erosion KW - Japan KW - Subduction zone KW - Landslides KW - Cosmogenic nuclides KW - Sediment budget Y1 - 2014 U6 - https://doi.org/10.1016/j.earscirev.2014.03.004 SN - 0012-8252 SN - 1872-6828 VL - 135 SP - 1 EP - 16 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Bloethe, Jan H. A1 - Munack, Henry A1 - Korup, Oliver A1 - Fuelling, Alexander A1 - Garzanti, Eduardo A1 - Resentini, Alberto A1 - Kubik, Peter W. T1 - Late Quaternary valley infill and dissection in the Indus River, western Tibetan Plateau margin JF - Quaternary science reviews : the international multidisciplinary research and review journal N2 - The Indus, one of Earth's major rivers, drains large parts of the NW Himalaya and the Transhimalayan ranges that form part of the western Tibetan Plateau margin. In the western Himalayan syntaxis, where local topographic relief exceeds 7 km, the Indus has incised a steep bedrock gorge at rates of several mm yr(-1). Upstream, however, the upper Indus and its tributaries alternate between bedrock gorges and broad alluvial flats flanked by the Ladakh and Zanskar ranges. We review the late Quaternary valley history in this region with a focus on the confluence of the Indus and Zanskar Rivers, where vast alluvial terrace staircases and lake sediments record major episodes of aggradation and incision. New absolute dating of high-level fluvial terrace remnants using cosmogenic Be-10, optically and infrared stimulated luminescence (OSL, IRSL) indicates at least two phases of late Quaternary valley infilling. These phases commenced before similar to 200 ka and similar to 50-20 ka, judging from terrace treads stranded >150 m and similar to 30-40 m above modern river levels, respectively. Numerous stacks of lacustrine sediments that straddle the Indus River >200 km between the city of Leh and the confluence with the Shyok River share a distinct horizontal alignment. Constraints from IRSL samples of lacustrine sequences from the Leh-Spituk area reveal a protracted lake phase from >177 ka to 72 ka, locally accumulating >50-m thick deposits. In the absence of tectonic faulting, major lithological differences, and stream capture, we attribute the formation of this and other large lakes in the region to natural damming by large landslides, glaciers, and alluvial fans. The overall patchy landform age constraints from earlier studies can be reconciled by postulating a major deglacial control on sediment flux, valley infilling, and subsequent incision that has been modulated locally by backwater effects of natural damming. While comparison with Pleistocene monsoon proxies reveals no obvious correlation, a lateor post-glacial sediment pulse seems a more likely source of this widespread sedimentation that has partly buried the dissected bedrock topography. Overall, the long residence times of fluvial, alluvial and lacustrine deposits in the region (>500 ka) support previous studies, but remain striking given the dominantly steep slopes and deeply carved valleys that characterise this high-altitude mountain desert. Recalculated late Quaternary rates of fluvial bedrock incision in the Indus and Zanskar of 1.5 +/- 0.2 mm yr(-1) are at odds with the longevity of juxtaposed valley-fill deposits, unless a lack of decisive lateral fluvial erosion helps to preserve these late Pleistocene sedimentary archives. We conclude that alternating, similar to 10(4)-yr long, phases of massive infilling and incision have dominated the late Quaternary history of the Indus valley below the western Tibetan Plateau margin. (C) 2014 Elsevier Ltd. All rights reserved. KW - Himalaya KW - Indus KW - Valley fills KW - Glaciation KW - Erosion KW - Lake sediment Y1 - 2014 U6 - https://doi.org/10.1016/j.quascirev.2014.04.011 SN - 0277-3791 VL - 94 SP - 102 EP - 119 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Gorum, Tolga A1 - Korup, Oliver A1 - van Westen, Cees J. A1 - van der Meijde, Mark A1 - Xu, Chong A1 - van der Meer, Freek D. T1 - Why so few? Landslides triggered by the 2002 Denali earthquake, Alaska JF - Quaternary science reviews : the international multidisciplinary research and review journal N2 - The 2002 M-w 7.9 Denali Fault earthquake, Alaska, provides an unparalleled opportunity to investigate in quantitative detail the regional hillslope mass-wasting response to strong seismic shaking in glacierized terrain. We present the first detailed inventory of similar to 1580 coseismic slope failures, out of which some 20% occurred above large valley glaciers, based on mapping from multi-temporal remote sensing data. We find that the Denali earthquake produced at least one order of magnitude fewer landslides in a much narrower corridor along the fault ruptures than empirical predictions for an M 8 earthquake would suggest, despite the availability of sufficiently steep and dissected mountainous topography prone to frequent slope failure. In order to explore potential controls on the reduced extent of regional coseismic landsliding we compare our data with inventories that we compiled for two recent earthquakes in periglacial and formerly glaciated terrain, i.e. at Yushu, Tibet (M-w 6.9, 2010), and Aysen Fjord, Chile (2007 M-w 6.2). Fault movement during these events was, similarly to that of the Denali earthquake, dominated by strike-slip offsets along near-vertical faults. Our comparison returns very similar coseismic landslide patterns that are consistent with the idea that fault type, geometry, and dynamic rupture process rather than widespread glacier cover were among the first-order controls on regional hillslope erosional response in these earthquakes. We conclude that estimating the amount of coseismic hillslope sediment input to the sediment cascade from earthquake magnitude alone remains highly problematic, particularly if glacierized terrain is involved. (C) 2014 Elsevier Ltd. All rights reserved. KW - Earthquake KW - Landslide KW - Glacial KW - Sediment cascade KW - Denali KW - Alaska Y1 - 2014 U6 - https://doi.org/10.1016/j.quascirev.2014.04.032 SN - 0277-3791 VL - 95 SP - 80 EP - 94 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Saito, H. A1 - Korup, Oliver A1 - Uchida, T. A1 - Hayashi, S. A1 - Oguchi, T. T1 - Rainfall conditions, typhoon frequency, and contemporary landslide erosion in Japan JF - Geology N2 - Dealing with predicted increases in extreme weather conditions due to climate change requires robust knowledge about controls on rainfall-triggered landslides. We explore relationships between rainfall and landslide size throughout the Japanese archipelago. We test whether the total volume of landslides can be predicted directly from rainfall totals, intensity, and duration using a nationwide inventory of 4744 rainfall-triggered landslides recorded from A.D. 2001 to 2011. We find that larger landslides were more abundant at the expense of smaller ones when total, maximum, and mean rainfall intensity exceeded similar to 250 mm, similar to 35 mm/h, and similar to 4 mm/h, respectively. Frequency distributions of these rainfall parameters are peaked and heavily skewed. Yet neither the most frequent nor the most extreme values of these rainfall metrics coincide consistently with the maximum landslide volumes. A striking decrease of landslide volumes at both mean and maximum rainfall intensity, as well as duration, points to an exhaustion in hillslope geomorphic response regardless of sample size, landslide type, mobilized volume, dominant lithology, or reporting bias. Our results underscore substantial offsets between the peaks of rainfall metrics and maximum associated landslide volumes, thus complicating straightforward estimates of geomorphic work from metrics of rainstorm magnitude or frequency. Only the rainfall total appears to be a suitable monotonic predictor of landslide volumes mobilized during typhoons and frontal storms. Y1 - 2014 U6 - https://doi.org/10.1130/G35680.1 SN - 0091-7613 SN - 1943-2682 VL - 42 IS - 11 SP - 999 EP - 1002 PB - American Institute of Physics CY - Boulder ER - TY - JOUR A1 - Weidinger, Johannes T. A1 - Korup, Oliver A1 - Munack, Henry A1 - Altenberger, Uwe A1 - Dunning, Stuart A. A1 - Tippelt, Gerold A1 - Lottermoser, Werner T1 - Giant rockslides from the inside JF - Earth & planetary science letters N2 - The growing body of research on large-scale mass wasting events so far has only scarcely investigated the sedimentology of chaotic deposits from non-volcanic terrestrial landslides such that any overarching and systematic terminological framework remains elusive. Yet recent work has emphasized the need for better understanding the internal structure and composition of rockslide deposits as a means to characterise the mechanics during the final stages of runout and emplacement. We offer a comprehensive overview on the occurrence of rock fragmentation and frictional melt both at different geographic locations, and different sections within large (>10(6) m(3)) rockslide masses. We argue that exposures of pervasively fragmented and interlocked jigsaw-cracked rock masses; basal melange containing rip-up clasts and phantom blocks; micro-breccia; and thin bands of basal frictionite are indispensable clues for identifying deposits from giant rockslides that may remain morphologically inconspicuous otherwise. These sedimentary assemblages are diagnostic tools for distinguishing large rockslide debris from macro and microscopically similar glacial deposits, tectonic fault-zone breccias, and impact breccias, and thus help avoid palaeoclimatic and tectonic misinterpretations, let alone misestimates of the hazard from giant rockslides. Moreover, experimental results from Mossbauer spectroscopy of frictionite samples support visual interpretations of thin sections, and demonstrate that short-lived (<10 s) friction-induced partial melting at temperatures >1500 degrees C in the absence of water occurred at the base of several giant moving rockslides. This finding supports previous theories of dry excess runout accompanied by comminution of rock masses down to gm-scale, and indicates that catastrophic motion of large fragmenting rock masses does not require water as a potential lubricant. KW - landslide KW - petrography KW - frictional melt KW - pseudotachylyte KW - breccia KW - Mossbauer spectroscopy Y1 - 2014 U6 - https://doi.org/10.1016/j.epsl.2013.12.017 SN - 0012-821X SN - 1385-013X VL - 389 SP - 62 EP - 73 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Meyer, Nele Kristin A1 - Schwanghart, Wolfgang A1 - Korup, Oliver A1 - Romstad, Bard A1 - Etzelmuller, Bernd T1 - Estimating the topographic predictability of debris flows JF - Geomorphology : an international journal on pure and applied geomorphology N2 - The Norwegian traffic network is impacted by about 2000 landslides, avalanches, and debris flows each year that incur high economic losses. Despite the urgent need to mitigate future losses, efforts to locate potential debris flow source areas have been rare at the regional scale. We tackle this research gap by exploring a minimal set of possible topographic predictors of debris flow initiation that we input to a Weights-of-Evidence (WofE) model for mapping the regional susceptibility to debris flows in western Norway. We use an inventory of 429 debris flows that were recorded between 1979 and 2008, and use the terrain variables of slope, total curvature, and contributing area (flow accumulation) to compute the posterior probabilities of local debris flow occurrence. The novelty of our approach is that we quantify the uncertainties in the WofE approach arising from different predictor classification schemes and data input, while estimating model accuracy and predictive performance from independent test data. Our results show that a percentile-based classification scheme excels over a manual classification of the predictor variables because differing abundances in manually defined bins reduce the reliability of the conditional independence tests, a key, and often neglected, prerequisite for the WofE method. The conditional dependence between total curvature and flow accumulation precludes their joint use in the model. Slope gradient has the highest true positive rate (88%), although the fraction of area classified as susceptible is very large (37%). The predictive performance, i.e. the reduction of false positives, is improved when combined with either total curvature or flow accumulation. Bootstrapping shows that the combination of slope and flow accumulation provides more reliable predictions than the combination of slope and total curvature, and helps refining the use of slope-area plots for identifying morphometric fingerprints of debris flow source areas, an approach used outside the field of landslide susceptibility assessments. KW - Weights-of-Evidence KW - Debris flows KW - Susceptibility KW - Slope-area plot KW - Process domains KW - Norway Y1 - 2014 U6 - https://doi.org/10.1016/j.geomorph.2013.10.030 SN - 0169-555X SN - 1872-695X VL - 207 SP - 114 EP - 125 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Korup, Oliver A1 - Rixen, C. T1 - Soil erosion and organic carbon export by wet snow avalanches JF - The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union N2 - Many mountain belts sustain prolonged snow cover for parts of the year, although enquiries into rates of erosion in these landscapes have focused almost exclusively on the snow-free periods. This raises the question of whether annual snow cover contributes significantly to modulating rates of erosion in high-relief terrain. In this context, the sudden release of snow avalanches is a frequent and potentially relevant process, judging from the physical damage to subalpine forest ecosystems, and the amount of debris contained in avalanche deposits. To quantitatively constrain this visual impression and to expand the sparse literature, we sampled sediment concentrations of n = 28 river-spanning snow-avalanche deposits (snow bridges) in the area around Davos, eastern Swiss Alps, and inferred an orders-of-magnitude variability in specific fine sediment and organic carbon yields (1.8 to 830 t km(-2) yr(-1), and 0.04 to 131 tC km(-2) yr(-1), respectively). A Monte Carlo simulation demonstrates that, with a minimum of free parameters, such variability is inherent to the geometric scaling used for computing specific yields. Moreover, the widely applied method of linearly extrapolating plot scale sample data may be prone to substantial under- or overestimates. A comparison of our inferred yields with previously published work demonstrates the relevance of wet snow avalanches as prominent agents of soil erosion and transporters of biogeochemical constituents to mountain rivers. Given that a number of snow bridges persisted below the insulating debris cover well into the summer months, snow-avalanche deposits also contribute to regulating in-channel sediment and organic debris storage on seasonal timescales. Finally, our results underline the potential shortcomings of neglecting erosional processes in the winter and spring months in mountainous terrain subjected to prominent snow cover. Y1 - 2014 U6 - https://doi.org/10.5194/tc-8-651-2014 SN - 1994-0416 SN - 1994-0424 VL - 8 IS - 2 SP - 651 EP - 658 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Vogel, Kristin A1 - Riggelsen, Carsten A1 - Korup, Oliver A1 - Scherbaum, Frank T1 - Bayesian network learning for natural hazard analyses JF - Natural hazards and earth system sciences N2 - Modern natural hazards research requires dealing with several uncertainties that arise from limited process knowledge, measurement errors, censored and incomplete observations, and the intrinsic randomness of the governing processes. Nevertheless, deterministic analyses are still widely used in quantitative hazard assessments despite the pitfall of misestimating the hazard and any ensuing risks. In this paper we show that Bayesian networks offer a flexible framework for capturing and expressing a broad range of uncertainties encountered in natural hazard assessments. Although Bayesian networks are well studied in theory, their application to real-world data is far from straightforward, and requires specific tailoring and adaptation of existing algorithms. We offer suggestions as how to tackle frequently arising problems in this context and mainly concentrate on the handling of continuous variables, incomplete data sets, and the interaction of both. By way of three case studies from earthquake, flood, and landslide research, we demonstrate the method of data-driven Bayesian network learning, and showcase the flexibility, applicability, and benefits of this approach. Our results offer fresh and partly counterintuitive insights into well-studied multivariate problems of earthquake-induced ground motion prediction, accurate flood damage quantification, and spatially explicit landslide prediction at the regional scale. In particular, we highlight how Bayesian networks help to express information flow and independence assumptions between candidate predictors. Such knowledge is pivotal in providing scientists and decision makers with well-informed strategies for selecting adequate predictor variables for quantitative natural hazard assessments. Y1 - 2014 U6 - https://doi.org/10.5194/nhess-14-2605-2014 SN - 1561-8633 VL - 14 IS - 9 SP - 2605 EP - 2626 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Munack, Henry A1 - Korup, Oliver A1 - Resentini, Alberto A1 - Limonta, Mara A1 - Garzanti, Eduardo A1 - Bloethe, Jan H. A1 - Scherler, Dirk A1 - Wittmann, Hella A1 - Kubik, Peter W. T1 - Postglacial denudation of western Tibetan Plateau margin outpaced by long-term exhumation JF - Geological Society of America bulletin N2 - The Indus River, one of Asia's premier rivers, drains the western Tibetan Plateau and the Nanga Parbat syntaxis. These two areas juxtapose some of the lowest and highest topographic relief and commensurate denudation rates in the Himalaya-Tibet orogen, respectively, yet the spatial pattern of denudation rates upstream of the syntaxis remains largely unclear, as does the way in which major rivers drive headward incision into the Tibetan Plateau. We report a new inventory of Be-10-based basinwide denudation rates from 33 tributaries flanking the Indus River along a 320 km reach across the western Tibetan Plateau margin. We find that denudation rates of up to 110 mm k.y.(-1) in the Ladakh and Zanskar Ranges systematically decrease eastward to 10 mm k.y.(-1) toward the Tibetan Plateau. Independent results from bulk petrographic and heavy mineral analyses support this denudation gradient. Assuming that incision along the Indus exerts the base-level control on tributary denudation rates, our data show a systematic eastward decrease of landscape downwearing, reaching its minimum on the Tibetan Plateau. In contrast, denudation rates increase rapidly 150-200 km downstream of a distinct knick-point that marks the Tibetan Plateau margin in the Indus River longitudinal profile. We infer that any vigorous headward incision and any accompanying erosional waves into the interior of the plateau mostly concerned reaches well below this plateau margin. Moreover, reported long-term (>10(6) yr) exhumation rates from low-temperature chronometry of 0.1-0.75 mm yr(-1) consistently exceed our Be-10-derived denudation rates. With averaging time scales of 10(3)-10(4) yr for our denudation data, we report postglacial rates of downwearing in a tectonically idle landscape. To counterbalance this apparent mismatch, denudation rates must have been higher in the Quaternary during glacial-interglacial intervals. Y1 - 2014 U6 - https://doi.org/10.1130/B30979.1 SN - 0016-7606 SN - 1943-2674 VL - 126 IS - 11-12 SP - 1580 EP - 1594 PB - American Institute of Physics CY - Boulder ER - TY - THES A1 - Munack, Henry T1 - From phantom blocks to denudational noise BT - downwearing of the Himalaya-Tibet orogen from a multi-scale perspective BT - die Abtragung des Himalaya-Tibet Orogens aus multiskaliger Perspektive N2 - Knowing the rates and mechanisms of geomorphic process that shape the Earth’s surface is crucial to understand landscape evolution. Modern methods for estimating denudation rates enable us to quantitatively express and compare processes of landscape downwearing that can be traced through time and space—from the seemingly intact, though intensely shattered, phantom blocks of the catastrophically fragmented basal facies of giant rockslides up to denudational noise in orogen-wide data sets averaging over several millennia. This great variety of spatiotemporal scales of denudation rates is both boon and bane of geomorphic process rates. Indeed, processes of landscape downwearing can be traced far back in time, helping us to understand the Earth’s evolution. Yet, this benefit may turn into a drawback due to scaling issues if these rates are to be compared across different observation timescales. This thesis investigates the mechanisms, patterns and rates of landscape downwearing across the Himalaya-Tibet orogen. Accounting for the spatiotemporal variability of denudation processes, this thesis addresses landscape downwearing on three distinctly different spatial scales, starting off at the local scale of individual hillslopes where considerable amounts of debris are generated from rock instantaneously: Rocksliding in active mountains is a major impetus of landscape downwearing. Study I provides a systematic overview of the internal sedimentology of giant rockslide deposits and thus meets the challenge of distinguishing them from macroscopically and microscopically similar glacial deposits, tectonic fault-zone breccias, and impact breccias. This distinction is important to avoid erroneous or misleading deduction of paleoclimatic or tectonic implications. -> Grain size analysis shows that rockslide-derived micro-breccia closely resemble those from meteorite impact or tectonic faults. -> Frictionite may occur more frequently that previously assumed. -> Mössbauer-spectroscopy derived results indicate basal rock melting in the absence of water, involving short-term temperatures of >1500°C. Zooming out, Study II tracks the fate of these sediments, using the example of the upper Indus River, NW India. There we use river sand samples from the Indus and its tributaries to estimate basin-averaged denudation rates along a ~320-km reach across the Tibetan Plateau margin, to answer the question whether incision into the western Tibetan Plateau margin is currently active or not. -> We find an about one-order-of-magnitude upstream decay—from 110 to 10 mm kyr^-1—of cosmogenic Be-10-derived basin-wide denudation rates across the morphological knickpoint that marks the transition from the Transhimalayan ranges to the Tibetan Plateau. This trend is corroborated by independent bulk petrographic and heavy mineral analysis of the same samples. -> From the observation that tributary-derived basin-wide denudation rates do not increase markedly until ~150–200 km downstream of the topographic plateau margin we conclude that incision into the Tibetan Plateau is inactive. -> Comparing our postglacial Be-10-derived denudation rates to long-term (>10^6 yr) estimates from low-temperature thermochronometry, ranging from 100 to 750 mm kyr^-1, points to an order- of-magnitude decay of rates of landscape downwearing towards present. We infer that denudation rates must have been higher in the Quaternary, probably promoted by the interplay of glacial and interglacial stages. Our investigation of regional denudation patterns in the upper Indus finally is an integral part of Study III that synthesizes denudation of the Himalaya-Tibet orogen. In order to identify general and time-invariant predictors for Be-10-derived denudation rates we analyze tectonic, climatic and topographic metrics from an inventory of 297 drainage basins from various parts of the orogen. Aiming to get insight to the full response distributions of denudation rate to tectonic, climatic and topographic candidate predictors, we apply quantile regression instead of ordinary least squares regression, which has been standard analysis tool in previous studies that looked for denudation rate predictors. -> We use principal component analysis to reduce our set of 26 candidate predictors, ending up with just three out of these: Aridity Index, topographic steepness index, and precipitation of the coldest quarter of the year. -> Topographic steepness index proves to perform best during additive quantile regression. Our consequent prediction of denudation rates on the basin scale involves prediction errors that remain between 5 and 10 mm kyr^-1. -> We conclude that while topographic metrics such as river-channel steepness and slope gradient—being representative on timescales that our cosmogenic Be-10-derived denudation rates integrate over—generally appear to be more suited as predictors than climatic and tectonic metrics based on decadal records. N2 - Die Kenntnis von Raten und Mechanismen geomorphologischer Prozesse, die die Erdoberfläche gestalten, ist entscheidend für das Verständnis von quartärer Landschaftsgeschichte. Denudationsraten sind dabei das Mittel zur Quantifizierung und zum Vergleich von Oberflächenabtrag; hinweg über zeitliche und räumliche Größenordnungen – von den optisch unversehrten, jedoch durchgehend zerrütteten “Phantom Blocks” der basalen Fazies katastrophaler Bergstürze bis hin zum “Denudational Noise”, dem durchaus informativen Rauschen in Datensätzen, die über ganze Orogene und tausende Jahre von Landschaftsgeschichte integrieren. Diese große räumlich-zeitliche Variabilität von Denudationsprozessen ist Chance und Herausforderung zugleich. Zum einen können Denudationsprozesse weit in der Zeit zurückverfolgt werden, was hilft, Landschaftsgeschichte nachzuvollziehen. Andererseits hat es sich gezeigt, dass geomorphologische Prozessraten mit dem Zeitraum ihrer Beobachtung skalieren, was einen Vergleich über zeitliche Größenordnungen hinweg erschwert. Diese Dissertation untersucht in drei Studien die Mechanismen, Muster und Raten von Denudation im Himalaja-Tibet Orogen. Der räumlichen (und zeitlichen) Variabilität von Denudationsprozessen folgend beginnt diese Arbeit dort, wo bedeutende Mengen von Festgestein schlagartig in erodierbaren Schutt umgewandelt werden: Bergstürze sind ein Hauptantrieb der Abtragung von aktiven Gebirgen. Studie I systematisiert die interne Sedimentologie gigantischer Bergsturzablagerungen. Sie adressiert damit Herausforderungen durch die makro- und mikroskopische Ähnlichkeit von Bergsturzablagerungen mit glazialen Ablagerungen, tektonischen Störungsbrekkzien und Impaktbrekkzien. Ziel einer solchen Systematisierung ist die Vermeidung fehlerhafter paläoklimatischer oder -tektonischer Interpretationen. -> Bergsturzbrekkzien sind auf mikroskopischer Ebene nicht von tektonischen oder Impaktbrekkzien unterscheidbar. -> Friktionit könnte weit häufiger vorkommen, als bisher angenommen. -> Mössbauer-Spektroskopie deutet auf Temperaturen ≥ 1500° C sowie die Abwesenheit von Wasser als Schmiermittel hin. Auf der mesoskaligen Ebene von Einzugsgebieten verfolgt Studie II, am Beispiel des oberen Indus in NW Indien den Weg dieser Sedimente, denn sie geben Auskunft über beckenweite Denudationsraten, sowie Pfade und Muster des Sedimenttransports am westlichen Tibetplateaurand. Diese Informationen sollen helfen, die Mechanismen der Einschneidung großer Flüsse in das Tibetplateau, sowie den gegenwärtigen erosionalen Status des Plateaurandes zu verstehen. -> Die beckenweiten Denudationsraten in den Tributären des Indus nehmen stromabwärts – und damit über den morphologischen Tibetplateaurand hinweg – von 10 auf 110 mm kyr^-1 zu. Dieser Trend wird durch unabhängige Petrographie- und Schwermineralanalysen aus denselben Proben nachgezeichnet. -> Es zeigt sich allerdings, dass der morphologische Plateaurand und der hierfür erwartbare Anstieg der Denudationsraten um ~150–200 km versetzt sind. Hieraus schließen wir, dass der westliche Rand des Tibetischen Plateaus rezent nicht maßgeblich erodiert wird. -> Ein Vergleich unserer postglazialen Denudationsraten von kosmogenem Be-10 mit Langzeit- (>10^6 yr)-Thermochronometriedaten von 100 bis 750 mm kyr^-1 deutet auf einen spätquartären Rückgang von Denudationsraten im Transhimalaya hin. Folglich muss es früher während des Quartärs Zeiten höherer erosionaler Effizienz gegeben haben. Studie III fokussiert schließlich, in einer Analyse beckenweiter Be-10-Denudationsraten, auf Denudationsmuster und -mechanismen für das gesamte Himalaja-Tibet Orogen. Auf der Suche nach zeit-invarianten tektonischen, klimatischen oder topographischen Prädiktoren für Denudationsraten wird ein Datensatz von 297 orogenweit verteilten Einzugsgebieten untersucht. Um Einblicke in die gesamte Response-Verteilung zwischen Denudationsrate und Prädiktor zu erhalten nutzen wir – anstelle der in diesem Zusammenhang vielbenutzten Methode der kleinsten Quadrate – Quantil-Regression. -> Dafür reduzieren wir einen Satz von 26 möglichen Prädiktoren, unter Nutzung der Hauptkomponentenanalyse, auf drei Prädiktoren: Ariditätsindex, topographischer Steilheitsindex und Niederschlag des kältesten Quartals. -> Die additive Quantil-Regression dieser drei Prädiktoren zeigt, dass der Steilheitsindex die besten Ergebnisse im Sinne einer zeit-invarianten Beziehung zwischen Denudationsrate und Prädiktoren liefert. -> Zusammenfassend zeigt sich, dass topographisch basierte Prädiktoren geeigneter für die Vorhersage von kosmogenen beckenweiten Denudationsraten sind als klimatische oder tektonische Prädiktoren. Wir erklären dieses Resultat mit den jeweils über Jahrtausende integrierenden Maßzahlen für Topographie und kosmogenen Denudationsraten, und der daraus folgenden Inkompatibilität der kosmogenen Denudationsraten mit den tektonischen und klimatischen Prädiktoren, die lediglich auf Jahrzehnten von Messungen beruhen. T2 - Von Phantomblöcken zu Denudationsrauschen KW - geomorphology KW - quaternary KW - denudation KW - Himalaya-Tibet orogen KW - cosmogenic nuclides KW - rockslide KW - Geomorphologie KW - Quartär KW - Denudation KW - Himalaya-Tibet Orogen KW - kosmogene Nuklide KW - Bergsturz Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-72629 ER - TY - JOUR A1 - Bruttel, Lisa Verena A1 - Friehe, Tim T1 - Can short-term incentives induce long-lasting cooperation? Results from a public-goods experiment JF - Journal of behavioral and experimental economics N2 - This paper investigates whether providing strong cooperation incentives only at the outset of a group interaction spills over to later periods to ensure cooperation in the long run. We study a repeated linear public-good game with punishment opportunities and a parameter change after the first ten (of twenty) rounds. Our data shows that cooperation among subjects who had experienced a higher marginal return on public-good contributions or low punishment costs in rounds 1-10 rapidly deteriorated in rounds 11-20 once these incentives were removed, eventually trending below the level of cooperation in the control group. This suggests the possibility of temporary incentives backfiring in the long run. This paper ties in with the literature highlighting the potentially adverse effects of the use of incentives. (C) 2014 Elsevier Inc. All rights reserved. KW - Public good game KW - Team KW - Punishment KW - Incentives KW - Experiment Y1 - 2014 U6 - https://doi.org/10.1016/j.socec.2014.09.001 SN - 2214-8043 SN - 2214-8051 VL - 53 SP - 120 EP - 130 PB - Elsevier CY - New York ER - TY - THES A1 - Maghsoudi, Samira T1 - Spatiotemporal microseismicity patterns and detection performance in mining environments Y1 - 2014 CY - Potsdam ER - TY - JOUR A1 - Braeuer, Benjamin A1 - Asch, Günter A1 - Hofstetter, Rami A1 - Haberland, Christian A1 - Jaser, D. A1 - El-Kelani, R. A1 - Weber, Michael H. T1 - Detailed seismicity analysis revealing the dynamics of the southern Dead Sea area JF - Journal of seismology N2 - Within the framework of the international DESIRE (DEad Sea Integrated REsearch) project, a dense temporary local seismological network was operated in the southern Dead Sea area. During 18 recording months, 648 events were detected. Based on an already published tomography study clustering, focal mechanisms, statistics and the distribution of the microseismicity in relation to the velocity models from the tomography are analysed. The determined b value of 0.74 leads to a relatively high risk of large earthquakes compared to the moderate microseismic activity. The distribution of the seismicity indicates an asymmetric basin with a vertical strike-slip fault forming the eastern boundary of the basin, and an inclined western boundary, made up of strike-slip and normal faults. Furthermore, significant differences between the area north and south of the Bokek fault were observed. South of the Bokek fault, the western boundary is inactive while the entire seismicity occurs on the eastern boundary and below the basin-fill sediments. The largest events occurred here, and their focal mechanisms represent the northwards transform motion of the Arabian plate along the Dead Sea Transform. The vertical extension of the spatial and temporal cluster from February 2007 is interpreted as being related to the locking of the region around the Bokek fault. North of the Bokek fault similar seismic activity occurs on both boundaries most notably within the basin-fill sediments, displaying mainly small events with strike-slip mechanism and normal faulting in EW direction. Therefore, we suggest that the Bokek fault forms the border between the single transform fault and the pull-apart basin with two active border faults. KW - Dead Sea basin KW - Microseismicity KW - Cluster KW - Pull-apart basin KW - Asymmetric basin KW - Transform fault Y1 - 2014 U6 - https://doi.org/10.1007/s10950-014-9441-4 SN - 1383-4649 SN - 1573-157X VL - 18 IS - 4 SP - 731 EP - 748 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Werner, Andrea A1 - Werner, Andreas A1 - Wieland, Ralf A1 - Kersebaum, Kurt-Christian A1 - Mirschel, Wilfried A1 - Ende, Hans-Peter A1 - Wiggering, Hubert T1 - Ex ante assessment of crop rotations focusing on energy crops using a multi-attribute decision-making method JF - Ecological indicators : integrating monitoring, assessment and management N2 - The cultivation of plants for use as energy resources is an agricultural and industrial sector with potentially synergistic benefits related to protecting the environment and generating income. Against the background of increasing land-use changes and new agricultural approaches to the production of energy crops, we present a method for identifying future-oriented crop rotations that supports both the economic and environmental components of decision-making strategies with respect to agriculture-related policy decisions (regional mission statements). The conflicting aspects of these objectives can be addressed with the analytic hierarchy process (AHP), a multi-attribute decision-making method that was integrated here. Three models are used to generate simulations of the defined objectives over a planning period of 30 years under the current climate scenario and provide input data for the multi-attribute assessment of several crop rotations. Based on the entire evaluation process, dimensionless global priority vectors are used to indicate how well the crop rotations meet the requirements of the defined mission statement. The method is tested in a municipality in NE Germany. (C) 2014 Elsevier Ltd. All rights reserved. KW - Agricultural management KW - Ex ante assessment KW - Multi-attribute decision-making KW - AHP KW - Crop rotation KW - Energy crops KW - Regional objectives KW - Indicators Y1 - 2014 U6 - https://doi.org/10.1016/j.ecolind.2014.03.013 SN - 1470-160X SN - 1872-7034 VL - 45 SP - 110 EP - 122 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Freundt, A. A1 - Grevemeyer, I. A1 - Rabbel, W. A1 - Hansteen, T. H. A1 - Hensen, C. A1 - Wehrmann, H. A1 - Kutterolf, S. A1 - Halama, Ralf A1 - Frische, M. T1 - Volatile (H2O, CO2, Cl, S) budget of the Central American subduction zone JF - International journal of earth sciences N2 - After more than a decade of multidisciplinary studies of the Central American subduction zone mainly in the framework of two large research programmes, the US MARGINS program and the German Collaborative Research Center SFB 574, we here review and interpret the data pertinent to quantify the cycling of mineral-bound volatiles (H2O, CO2, Cl, S) through this subduction system. For input-flux calculations, we divide the Middle America Trench into four segments differing in convergence rate and slab lithological profiles, use the latest evidence for mantle serpentinization of the Cocos slab approaching the trench, and for the first time explicitly include subduction erosion of forearc basement. Resulting input fluxes are 40-62 (53) Tg/Ma/m H2O, 7.8-11.4 (9.3) Tg/Ma/m CO2, 1.3-1.9 (1.6) Tg/Ma/m Cl, and 1.3-2.1 (1.6) Tg/Ma/m S (bracketed are mean values for entire trench length). Output by cold seeps on the forearc amounts to 0.625-1.25 Tg/Ma/m H2O partly derived from the slab sediments as determined by geochemical analyses of fluids and carbonates. The major volatile output occurs at the Central American volcanic arc that is divided into ten arc segments by dextral strike-slip tectonics. Based on volcanic edifice and widespread tephra volumes as well as calculated parental magma masses needed to form observed evolved compositions, we determine long-term (10(5) years) average magma and K2O fluxes for each of the ten segments as 32-242 (106) Tg/Ma/m magma and 0.28-2.91 (1.38) Tg/Ma/m K2O (bracketed are mean values for entire Central American volcanic arc length). Volatile/K2O concentration ratios derived from melt inclusion analyses and petrologic modelling then allow to calculate volatile fluxes as 1.02-14.3 (6.2) Tg/Ma/m H2O, 0.02-0.45 (0.17) Tg/Ma/m CO2, and 0.07-0.34 (0.22) Tg/Ma/m Cl. The same approach yields long-term sulfur fluxes of 0.12-1.08 (0.54) Tg/Ma/m while present-day open-vent SO2-flux monitoring yields 0.06-2.37 (0.83) Tg/Ma/m S. Input-output comparisons show that the arc water fluxes only account for up to 40 % of the input even if we include an "invisible" plutonic component constrained by crustal growth. With 20-30 % of the H2O input transferred into the deeper mantle as suggested by petrologic modeling, there remains a deficiency of, say, 30-40 % in the water budget. At least some of this water is transferred into two upper-plate regions of low seismic velocity and electrical resistivity whose sizes vary along arc: one region widely envelopes the melt ascent paths from slab top to arc and the other extends obliquely from the slab below the forearc to below the arc. Whether these reservoirs are transient or steady remains unknown. KW - Subduction input KW - Forearc dewatering KW - Arc magmatism KW - Subduction fluids Y1 - 2014 U6 - https://doi.org/10.1007/s00531-014-1001-1 SN - 1437-3254 SN - 1437-3262 VL - 103 IS - 7 SP - 2101 EP - 2127 PB - Springer CY - New York ER - TY - JOUR A1 - Maslin, Mark A. A1 - Brierley, Chris M. A1 - Milner, Alice M. A1 - Shultz, Susanne A1 - Trauth, Martin H. A1 - Wilson, Katy E. T1 - East African climate pulses and early human evolution JF - Quaternary science reviews : the international multidisciplinary research and review journal N2 - Current evidence suggests that all of the major events in hominin evolution have occurred in East Africa. Over the last two decades, there has been intensive work undertaken to understand African palaeoclimate and tectonics in order to put together a coherent picture of how the environment of East Africa has varied in the past. The landscape of East Africa has altered dramatically over the last 10 million years. It has changed from a relatively flat, homogenous region covered with mixed tropical forest, to a varied and heterogeneous environment, with mountains over 4 km high and vegetation ranging from desert to cloud forest. The progressive rifting of East Africa has also generated numerous lake basins, which are highly sensitive to changes in the local precipitation-evaporation regime. There is now evidence that the presence of precession-driven, ephemeral deep-water lakes in East Africa were concurrent with major events in hominin evolution. It seems the unusual geology and climate of East Africa created periods of highly variable local climate, which, it has been suggested could have driven hominin speciation, encephalisation and dispersal out of Africa. One example is the significant hominin speciation and brain expansion event at -1.8 Ma that seems to have been coeval with the occurrence of highly variable, extensive, deep-water lakes. This complex, climatically very variable setting inspired first the variability selection hypothesis, which was then the basis for the pulsed climate variability hypothesis. The newer of the two suggests that the long-term drying trend in East Africa was punctuated by episodes of short, alternating periods of extreme humidity and aridity. Both hypotheses, together with other key theories of climate-evolution linkages, are discussed in this paper. Though useful the actual evolution mechanisms, which led to early hominins are still unclear and continue to be debated. However, it is clear that an understanding of East African lakes and their palaeoclimate history is required to understand the context within which humans evolved and eventually left East Africa. (C) 2014 The Authors. Published by Elsevier Ltd. KW - Human evolution KW - East Africa KW - Palaeoclimatology KW - Palaeoliminology KW - Tectonics KW - Hominin KW - Orbital forcing KW - Cenozoic climate transitions KW - Pulsed climate variability hypothesis Y1 - 2014 U6 - https://doi.org/10.1016/j.quascirev.2014.06.012 SN - 0277-3791 VL - 101 SP - 1 EP - 17 PB - Elsevier CY - Oxford ER - TY - INPR A1 - Freundt, A. A1 - Halama, Ralf A1 - Suess, E. A1 - Voelker, D. T1 - Introduction to the special issue on SFB 574 "Volatiles and fluids in subduction zones: climate feedback and trigger mechanisms for natural disasters" T2 - International journal of earth sciences Y1 - 2014 U6 - https://doi.org/10.1007/s00531-014-1059-9 SN - 1437-3254 SN - 1437-3262 VL - 103 IS - 7 SP - 1729 EP - 1731 PB - Springer CY - New York ER - TY - JOUR A1 - Garcin, Yannick A1 - Schefuss, Enno A1 - Schwab, Valerie F. A1 - Garreta, Vincent A1 - Gleixner, Gerd A1 - Vincens, Annie A1 - Todou, Gilbert A1 - Sene, Olivier A1 - Onana, Jean-Michel A1 - Achoundong, Gaston A1 - Sachse, Dirk T1 - Reconstructing C-3 and C-4 vegetation cover using n-alkane carbon isotope ratios in recent lake sediments from Cameroon, Western Central Africa JF - Geochimica et cosmochimica acta : journal of the Geochemical Society and the Meteoritical Society N2 - Trees and shrubs in tropical Africa use the C-3 cycle as a carbon fixation pathway during photosynthesis, while grasses and sedges mostly use the C-4 cycle. Leaf-wax lipids from sedimentary archives such as the long-chain n-alkanes (e.g., n-C-27 to n-C-33) inherit carbon isotope ratios that are representative of the carbon fixation pathway. Therefore, n-alkane delta C-13 values are often used to reconstruct past C-3/C-4 composition of vegetation, assuming that the relative proportions of C-3 and C-4 leaf waxes reflect the relative proportions of C-3 and C-4 plants. We have compared the delta C-13 values of n-alkanes from modern C-3 and C-4 plants with previously published values from recent lake sediments and provide a framework for estimating the fractional contribution (areal-based) of C-3 vegetation cover (f(C3)) represented by these sedimentary archives. Samples were collected in Cameroon, across a latitudinal transect that accommodates a wide range of climate zones and vegetation types, as reflected in the progressive northward replacement of C-3-dominated rain forest by C-4-dominated savanna. The C-3 plants analysed were characterised by substantially higher abundances of n-C-29 alkanes and by substantially lower abundances of n-C-33 alkanes than the C-4 plants. Furthermore, the sedimentary delta C-13 values of n-C-29 and n-C-31 alkanes from recent lake sediments in Cameroon (-37.4%) to 26.5%) were generally within the range of delta C-13 values for C-3 plants, even when from sites where C-4 plants dominated the catchment vegetation. In such cases simple linear mixing models fail to accurately reconstruct the relative proportions of C-3 and C-4 vegetation cover when using the delta C-13 values of sedimentary n-alkanes, overestimating the proportion of C-3 vegetation, likely as a consequence of the differences in plant wax production, preservation, transport, and/or deposition between C-3 and C-4 plants. We therefore tested a set of non-linear binary mixing models using delta C-13 values from both C-3 and C-4 vegetation as end-members. The non-linear models included a sigmoid function (sine-squared) that describes small variations in the f(C3) values as the minimum and maximum delta C-13 values are approached, and a hyperbolic function that takes into account the differences between C-3 and C-4 plants discussed above. Model fitting and the estimation of uncertainties were completed using the Monte Carlo algorithm and can be improved by future data addition. Models that provided the best fit with the observed delta C-13 values of sedimentary n-alkanes were either hyperbolic functions or a combination of hyperbolic and sine-squared functions. Such non-linear models may be used to convert delta C-13 measurements on sedimentary n-alkanes directly into reconstructions of C-3 vegetation cover. (C) 2014 Elsevier Ltd. All rights reserved. Y1 - 2014 U6 - https://doi.org/10.1016/j.gca.2014.07.004 SN - 0016-7037 SN - 1872-9533 VL - 142 SP - 482 EP - 500 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Zhao, Peng A1 - Kuhn, Daniela A1 - Oye, Volker A1 - Cesca, Simone T1 - Evidence for tensile faulting deduced from full waveform moment tensor inversion during the stimulation of the Basel enhanced geothermal system JF - Geothermics : an international journal of geothermal research and its applications N2 - Our study presents the results of a moment tensor inversion of 19 microseismic events with M-L between 2.0 and 3.4, associated with the stimulation operation of an enhanced geothermal reservoir in Basel, Switzerland, in 2006. We adopt a three-step procedure to retrieve point source solution parameters based on full waveform inversion. The inversion is performed by fitting displacement amplitude spectra and displacement seismograms in the first and second step, respectively, assuming a double couple source model and thus obtaining focal solutions for all 19 events. Our results are in agreement with focal mechanisms from a previous study, which employed P wave first-motion polarities from more than 40 stations, whereas our solutions are achieved using full waveform data recorded by less than 10 surface stations. In the last step, a full moment tensor inversion is performed. The results from the moment tensor inversion show an improvement on the waveform fitting compared to the double couple models, which is verified by an F-test. We investigate the stability of the moment tensor solutions by employing different velocity models. The isotropic components of the moment tensor solutions of some events are not negligible, suggesting source volume changes due to fluid injection. Events with significant isotropic components occurred mainly during the stimulation phase and close to the injection well. On the other hand, events that occurred in the post-stimulation phase are predominantly pure shear failure and located further away from the well bore. These spatio-temporal patterns can be explained by the influence of pore pressure variations during and after the hydraulic stimulation at the geothermal site. (C) 2014 Elsevier Ltd. All rights reserved. KW - Induced seismicity KW - Hydraulic fracture KW - Crack opening and closure KW - Source mechanism KW - F-test Y1 - 2014 U6 - https://doi.org/10.1016/j.geothermics.2014.01.003 SN - 0375-6505 SN - 1879-3576 VL - 52 SP - 74 EP - 83 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Wolff, Christian Michael A1 - Kristen-Jenny, Iris A1 - Schettler, Georg A1 - Plessen, Birgit A1 - Meyer, Hanno A1 - Dulski, Peter A1 - Naumann, Rudolf A1 - Brauer, Achim A1 - Verschuren, Dirk A1 - Haug, Gerald H. T1 - Modern seasonality in Lake Challa (Kenya/Tanzania) and its sedimentary documentation in recent lake sediments JF - Limnology and oceanography N2 - From November 2006 to January 2010, a sediment trap that was cleared monthly was deployed in Lake Challa, a deep stratified freshwater lake on the eastern slope of Mt. Kilimanjaro in southern Kenya. Geochemical data from sediment trap samples were compared with a broad range of limnological and meteorological parameters to characterize the effect of single parameters on productivity and sedimentation processes in the crater basin. During the southern hemisphere summer (November-March), when the water temperature is high and the lake is biologically productive (nondiatom algae), calcite predominated in the sediment trap samples. During the "long rain" season (March-May) a small amount of organic matter and lithogenic material caused by rainfall appeared. This was followed by the cool and windy months of the southern hemisphere winter (June-October) when diatoms were the main component, indicating a diatom bloom initiated by improvement of nutrient availability related to upwelling processes. The sediment trap data support the hypothesis that the light-dark lamination couplets, which are abundant in Lake Challa cores, reflect seasonal delivery to the sediments of diatom-rich particulates during the windy months and diatom-poor material during the wet season. However, interannual and spatial variability in upwelling and productivity patterns, as well as El Nino-Southern Oscillation (ENSO)-related rainfall and drought cycles, exert a strong influence on the magnitude and geochemical composition of particle export to the hypolimnion of Lake Challa. Y1 - 2014 U6 - https://doi.org/10.4319/lo.2014.59.5.1621 SN - 0024-3590 SN - 1939-5590 VL - 59 IS - 5 SP - 1621 EP - 1636 PB - Wiley CY - Waco ER - TY - JOUR A1 - Albrich, Sergi A1 - Frijia, Gianluca A1 - Parente, Mariano A1 - Caus, Esmeralda T1 - The evolution of the earliest representatives of the genus Orbitoides: Implications for Upper Cretaceous biostratigraphy JF - Cretaceous research N2 - The biostratigraphy of Campanian-Maastrichtian carbonate platforms is largely based on the larger foraminiferal genus Orbitoides. However, while the taxonomy and the chronostratigraphic age of the younger species of this genus are well established, there are still many controversies on the earliest species. We have restudied their morphological characters using a large collection of samples from the type-localities and from continuous sections in the southern Pyrenees. Based on these new observations, the long forgotten species O. sanctae-pelagiae is reinstated, while O. dordoniensis is considered a junior synonym. Successive populations of O. hottingeri, O. sanctae-pelagiae and O. douvillei show gradual morphological changes in time marked by an increase in the size and complexity of the macrospheric embryonal apparatus, an increase of the size of the adult specimens of both generations and the progressive appearance and development of true lateral chamberlets. The Font de les Bagasses Unit in the southern Pyrenees preserves a high-resolution archive of the evolution of the earliest Orbitoides. Strontium isotope stratigraphy indicates that the oldest species, O. hottingeri, made its first appearance in the earliest Campanian, close to the Santonian-Campanian boundary, and was replaced by O. sanctae-pelagiae at a level closely corresponding to the boundary between the Placenticeras bidorsatum and Menabites delawarensis ammonite zones. (C) 2014 Elsevier Ltd. All rights reserved. KW - Larger foraminifera KW - Biostratigraphy KW - Strontium isotope stratigraphy KW - Late cretaceous KW - Orbitoides Y1 - 2014 U6 - https://doi.org/10.1016/j.cretres.2014.04.013 SN - 0195-6671 SN - 1095-998X VL - 51 SP - 22 EP - 34 PB - Elsevier CY - London ER - TY - JOUR A1 - Dietze, Elisabeth A1 - Maussion, F. A1 - Ahlborn, M. A1 - Diekmann, Bernhard A1 - Hartmann, K. A1 - Henkel, K. A1 - Kasper, T. A1 - Lockot, G. A1 - Opitz, S. A1 - Haberzettl, T. T1 - Sediment transport processes across the Tibetan Plateau inferred from robust grain-size end members in lake sediments JF - Climate of the past : an interactive open access journal of the European Geosciences Union N2 - Grain-size distributions offer powerful proxies of past environmental conditions that are related to sediment sorting processes. However, they are often of multimodal character because sediments can get mixed during deposition. To facilitate the use of grain size as palaeoenvironmental proxy, this study aims to distinguish the main detrital processes that contribute to lacustrine sedimentation across the Tibetan Plateau using grain-size end-member modelling analysis. Between three and five robust grain-size end-member subpopulations were distinguished at different sites from similarly-likely end-member model runs. Their main modes were grouped and linked to common sediment transport and depositional processes that can be associated with contemporary Tibetan climate (precipitation patterns and lake ice phenology, gridded wind and shear stress data from the High Asia Reanalysis) and local catchment configurations. The coarse sands and clays with grain-size modes > 250 mu m and < 2 mu m were probably transported by fluvial processes. Aeolian sands (similar to 200 mu m) and coarse local dust (similar to 60 mu m), transported by saltation and in near-surface suspension clouds, are probably related to occasional westerly storms in winter and spring. Coarse regional dust with modes similar to 25 mu m may derive from near-by sources that keep in longer term suspension. The continuous background dust is differentiated into two robust end members (modes: 5-10 and 2-5 mu m) that may represent different sources, wind directions and/or sediment trapping dynamics from long-range, upper-level westerly and episodic northerly wind transport. According to this study grain-size end members of only fluvial origin contribute small amounts to mean Tibetan lake sedimentation (19 +/- 5%), whereas local to regional aeolian transport and background dust deposition dominate the clastic sedimentation in Tibetan lakes (contributions: 42 +/- 14% and 51 +/- 11%). However, fluvial and alluvial reworking of aeolian material from nearby slopes during summer seems to limit end-member interpretation and should be cross-checked with other proxy information. If not considered as a stand-alone proxy, a high transferability to other regions and sediment archives allows helpful reconstructions of past sedimentation history. Y1 - 2014 U6 - https://doi.org/10.5194/cp-10-91-2014 SN - 1814-9324 SN - 1814-9332 VL - 10 IS - 1 SP - 91 EP - 106 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Fahle, Marcus A1 - Dietrich, Ottfried T1 - Estimation of evapotranspiration using diurnal groundwater level fluctuations: Comparison of different approaches with groundwater lysimeter data JF - Water resources research N2 - In wetlands or riparian areas, water withdrawal by plants with access to groundwater or the capillary fringe often causes diurnal groundwater fluctuations. Various approaches use the characteristics of these fluctuations for estimation of daily groundwater evapotranspiration rates. The objective of this paper was to review the available methods, compare them with measured evapotranspiration and assess their recharge assumptions. For this purpose, we employed data of 85 rain-free days of a weighable groundwater lysimeter situated at a grassland site in the Spreewald wetland in north-east Germany. Measurements of hourly recharge and daily evapotranspiration rates were used to assess the different approaches. Our results showed that a maximum of 50% of the day to day variance of the daily evapotranspiration rates could be explained by the approaches based on groundwater fluctuations. Simple and more complex methods performed similarly. For some of the approaches, there were indications that erroneous assumptions compensated each other (e.g., when overestimated recharge counteracted underestimated storage change). We found that the usage of longer time spans resulted in improved estimates of the daily recharge rates and that the estimates were further enhanced by including two night averages. When derived from fitting estimates of recharge or evapotranspiration with according measurements the specific yield, needed to convert changes in water level to water volumes, differed considerably among the methods (from 0.022 to 0.064). Thus, the specific yield can be seen as correction factor that compensates for inadequate process descriptions. KW - evapotranspiration KW - groundwater lysimeter KW - specific yield KW - diurnal signal KW - phreatophytes KW - wetland Y1 - 2014 U6 - https://doi.org/10.1002/2013WR014472 SN - 0043-1397 SN - 1944-7973 VL - 50 IS - 1 SP - 273 EP - 286 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Basavaiah, Nathani A1 - Wiesner, M. G. A1 - Anoop, Ambili A1 - Menzel, P. A1 - Nowaczyk, Norbert R. A1 - Deenadayalan, K. A1 - Brauer, Achim A1 - Gaye, Birgit A1 - Naumann, R. A1 - Riedel, N. A1 - Stebich, M. A1 - Prasad, Sushma T1 - Physicochemical analyses of surface sediments from the Lonar Lake, central India - implications for palaeoenvironmental reconstruction JF - Fundamental and applied limnology : official journal of the International Association of Theoretical and Applied Limnology N2 - We report the results of our investigations on the catchment area, surface sediments, and hydrology of the monsoonal Lonar Lake, central India. Our results indicate that the lake is currently stratified with an anoxic bottom layer, and there is a spatial heterogeneity in the sensitivity of sediment parameters to different environmental processes. In the shallow (0-5 m) near shore oxic-suboxic environments the lithogenic and terrestrial organic content is high and spatially variable, and the organics show degradation in the oxic part. Due to aerial exposure resulting from lake level changes of at least 3m, the evaporitic carbonates are not completely preserved. In the deep water (>5 m) anoxic environment the lithogenics are uniformly distributed and the delta C-13 is an indicator not only for aquatic vs. terrestrial plants but also of lake pH and salinity. The isotopic composition of the evaporites is dependent not only on the isotopic composition of source water (monsoon rainfall and stream inflow) and evaporation, but is also influenced by proximity to the isotopically depleted stream inflow. We conclude that in the deep water environment lithogenic content, and isotopic composition of organic matter can be used for palaeoenvironmental reconstruction. KW - isotopes KW - lonar lake KW - modern surface sediments KW - magnetic parameters KW - monsoon KW - palaeoenvironmental proxies Y1 - 2014 U6 - https://doi.org/10.1127/1863-9135/2014/0515 SN - 1863-9135 VL - 184 IS - 1 SP - 51 EP - 68 PB - Schweizerbart CY - Stuttgart ER - TY - JOUR A1 - Nishihara, Yu A1 - Ohuchi, Tomohiro A1 - Kawazoe, Takaaki A1 - Spengler, Dirk A1 - Tasaka, Miki A1 - Kikegawa, Takumi A1 - Suzuki, Akio A1 - Ohtani, Eiji T1 - Rheology of fine-grained forsterite aggregate at deep upper mantle conditions JF - Journal of geophysical research : Solid earth KW - high-pressure KW - olivine KW - rheology KW - upper mantle Y1 - 2014 U6 - https://doi.org/10.1002/2013JB010473 SN - 2169-9313 SN - 2169-9356 VL - 119 IS - 1 SP - 253 EP - 273 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Farinotti, Daniel A1 - King, Edward C. A1 - Albrecht, Anika A1 - Huss, Matthias A1 - Gudmundsson, Gudmundur Hilmar T1 - The bedrock topography of Starbuck Glacier, Antarctic Peninsula, as determined by radio-echo soundings and flow modeling JF - Annals of glaciology KW - Antarctic glaciology KW - glaciological instruments and methods KW - ground-penetrating radar KW - ice-shelf tributary glaciers KW - radio-echo sounding Y1 - 2014 U6 - https://doi.org/10.3189/2014AoG67A025 SN - 0260-3055 SN - 1727-5644 VL - 55 IS - 67 SP - 22 EP - 28 PB - International Glaciological Society CY - Cambridge ER - TY - JOUR A1 - Müller, Hans J. A1 - Beckmann, Felix A1 - Dobson, David P. A1 - Hunt, Simon A. A1 - Lathe, Christian A1 - Stroncik, Nicole T1 - New techniques for high pressure falling sphere viscosimetry in DIA-type large volume presses JF - High pressure research KW - falling sphere viscosimetry KW - inelastic properties KW - high pressure KW - X-radiography Y1 - 2014 U6 - https://doi.org/10.1080/08957959.2014.950262 SN - 0895-7959 SN - 1477-2299 VL - 34 IS - 3 SP - 345 EP - 354 PB - Routledge, Taylor & Francis Group CY - Abingdon ER - TY - JOUR A1 - Kneis, David A1 - Chatterjee, C. A1 - Singh, R. T1 - Evaluation of TRMM rainfall estimates over a large Indian river basin (Mahanadi) JF - Hydrology and earth system sciences : HESS N2 - The paper examines the quality of satellite-abased precipitation estimates for the lower Mahanadi River basin (eastern India). The considered data sets known as 3B42 and 3B42-RT (version 7/7A) are routinely produced by the tropical rainfall measuring mission (TRMM) from passive microwave and infrared recordings. While the 3B42-RT data are disseminated in real time, the gauge-aadjusted 3B42 data set is published with a delay of some months. The quality of the two products was assessed in a two-astep procedure. First, the correspondence between the remotely sensed precipitation rates and rain gauge data was evaluated at the subbasin scale. Second, the quality of the rainfall estimates was assessed by analysing their performance in the context of rainfall-arunoff simulation. At sub-abasin level (4000 to 16 000 km(2)) the satellite-abased areal precipitation estimates were found to be moderately correlated with the gauge-abased counterparts (R-2 of 0.64-0.74 for 3B42 and 0.59-0.72 for 3B42-RT). Significant discrepancies between TRMM data and ground observations were identified at high-aintensity levels. The rainfall depth derived from rain gauge data is often not reflected by the TRMM estimates (hit rate < 0.6 for ground-abased intensities > 80 mm day(-1)). At the same time, the remotely sensed rainfall rates frequently exceed the gauge-abased equivalents (false alarm ratios of 0.2-0.6). In addition, the real-atime product 3B42-RT was found to suffer from a spatially consistent negative bias. Since the regionalisation of rain gauge data is potentially associated with a number of errors, the above results are subject to uncertainty. Hence, a validation against independent information, such as stream flow, was essential. In this case study, the outcome of rainfall-arunoff simulation experiments was consistent with the above-mentioned findings. The best fit between observed and simulated stream flow was obtained if rain gauge data were used as model input (Nash-Sutcliffe index of 0.76-0.88 at gauges not affected by reservoir operation). This compares to the values of 0.71-0.78 for the gauge-djusted TRMM 3B42 data and 0.65-0.77 for the 3B42-RT real-atime data. Whether the 3B42-RT data are useful in the context of operational runoff prediction in spite of the identified problems remains a question for further research. Y1 - 2014 U6 - https://doi.org/10.5194/hess-18-2493-2014 SN - 1027-5606 SN - 1607-7938 VL - 18 IS - 7 SP - 2493 EP - 2502 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Nussbaumer, S. A1 - Schaub, Y. A1 - Huggel, C. A1 - Walz, Ariane T1 - Risk estimation for future glacier lake outburst floods based on local land-use changes JF - Natural hazards and earth system sciences N2 - Effects of climate change are particularly strong in high-mountain regions. Most visibly, glaciers are shrinking at a rapid pace, and as a consequence, glacier lakes are forming or growing. At the same time the stability of mountain slopes is reduced by glacier retreat, permafrost thaw and other factors, resulting in an increasing landslide hazard which can potentially impact lakes and therewith trigger far-reaching and devastating outburst floods. To manage risks from existing or future lakes, strategies need to be developed to plan in time for adequate risk reduction measures at a local level. However, methods to assess risks from future lake outbursts are not available and need to be developed to evaluate both future hazard and future damage potential. Here a method is presented to estimate future risks related to glacier lake outbursts for a local site in southern Switzerland (Naters, Valais). To generate two hazard scenarios, glacier shrinkage and lake formation modelling was applied, combined with simple flood modelling and field work. Furthermore, a land-use model was developed to quantify and allocate land-use changes based on local-to-regional storylines and three scenarios of land-use driving forces. Results are conceptualized in a matrix of three land-use and two hazard scenarios for the year 2045, and show the distribution of risk in the community of Naters, including high and very high risk areas. The study underlines the importance of combined risk management strategies focusing on land-use planning, on vulnerability reduction, as well as on structural measures (where necessary) to effectively reduce future risks related to lake outburst floods. Y1 - 2014 U6 - https://doi.org/10.5194/nhess-14-1611-2014 SN - 1561-8633 VL - 14 IS - 6 SP - 1611 EP - 1624 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Menges, Johanna A1 - Huguet, C. A1 - Alcaniz, Josep M. A1 - Fietz, Susanne A1 - Sachse, Dirk A1 - Rosell-Mele, A. T1 - Influence of water availability in the distributions of branched glycerol dialkyl glycerol tetraether in soils of the Iberian Peninsula JF - Biogeosciences Y1 - 2014 U6 - https://doi.org/10.5194/bg-11-2571-2014 SN - 1726-4170 SN - 1726-4189 VL - 11 IS - 10 SP - 2571 EP - 2581 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Huck, Stefan A1 - Stein, Melody A1 - Immenhauser, Adrian A1 - Skelton, Peter W. A1 - Christ, Nicolas A1 - Foellmi, Karl B. A1 - Heimhofer, Ulrich T1 - Response of proto-North Atlantic carbonate-platform ecosystems to OAE1a-related stressors JF - Sedimentary geology : international journal of applied and regional sedimentology N2 - Integrated biostratigraphic-chemostratigraphic studies provide evidence that the proto-North Atlantic realm witnessed major changes in carbonate platform production in the run-up of the Early Aptian oceanic anoxic event (OAE) 1a. Whereas pervasive growth of Lithocodium microencrusters represents an early harbinger of OAE1a-related environmental perturbation, the subsequent replacement of oligotrophic rudist-coral-nerineid by mesotrophic orbitolinid-oyster communities was clearly associated with the event itself. In order to test the supra-regional relevance of this major community replacement, two shallow-water sections in the southern Lusitanian Basin (Portugal) are investigated by means of geochemistry (carbon and oxygen isotopes), cement petrography and detailed sedimentological analysis. The focus is on a regional, prominent discontinuity surface (S4) at the transition between oligotrophic and mesotrophic carbonate platform production, which might indicate that the major biotic change could have been associated with a phase of non-sedimentation and possibly erosion. The studied sections (Sao Julia, Crismina) provide evidence that the major Early Aptian biotic turnover was preceded by numerous subordinate but significant changes in platform ecology, which mirrored a series of progressive short-term environmental changes in the course of OAE1. Several transient mass occurrences of orbitolinids indicate repeated phases of ecological stress arguably due to enhanced nutrient input and deepening. Small-scale sea-level changes at parasequence level below the major discontinuity surface are revealed by alternations of rudist assemblages dominated by clinger or recumbent forms as well as intercalated hardground and subaerial exposure stages. Expanded phases of subaerial exposure, however, can be largely ruled out following the geochemical and cement-petrographic data presented here. Enhanced continent-derived siliciclastic input characterising the lower orbitolinid-oyster dominated limestones is in support of a shift to more humid conditions during the middle Early Aptian. This is in line with palaeoclimatic data, which propose a southward movement of the mid-latitude arid climate belt during this time. The documented rapid replacement of oligotrophic assemblages by various environmental-stress adapted carbonate platform communities might be seen as explanation for ongoing Early Aptian proto-North Atlantic carbonate production during a time of widespread platform demise and drowning in the northern Tethyan realm. (C) 2014 Elsevier B.V. All rights reserved. KW - Aptian KW - Oceanic anoxic event 1a KW - Proto-North Atlantic KW - Discontinuity surfaces KW - Carbonate platform response KW - Carbon and oxygen isotopes Y1 - 2014 U6 - https://doi.org/10.1016/j.sedgeo.2014.08.003 SN - 0037-0738 SN - 1879-0968 VL - 313 SP - 15 EP - 31 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Polanski, Stefan A1 - Fallah, Bijan A1 - Befort, Daniel J. A1 - Prasad, Sushma A1 - Cubasch, Ulrich T1 - Regional moisture change over India during the past millennium: A comparison of multi-proxy reconstructions and climate model simulations JF - Global and planetary change N2 - The Indian Monsoon Variability during the past Millennium has been simulated with the ECHAM5 model in two different time slices: Medieval Climate Anomaly and the Little Ice Age. The simulations are compared with new centennial-resolving paleo-reconstructions inferred from various well-dated multi-proxies from two core regions, the Himalaya and Central India. A qualitative moisture index is derived from the proxies and compared with simulated moisture anomalies. The reconstructed paleo-hydrological changes between the Little Ice Age and the Medieval Climate Anomaly depict a dipole pattern between Himalaya and Central India, which is also captured by the model. In the Medieval Climate Anomaly the model exhibits stronger (weaker) dipole signals during summer (winter) compared to Little Ice Age. In summer (winter) months of "Medieval Climate Anomaly minus Little Ice Age" the model simulates wetter conditions over eastern (western and central) Himalaya. Over Central India, a simulated weakening of Indian Summer Monsoon during warmer climate is coincident with reconstructed drying signal in the Lonar Lake record. Based on the model simulations, we can differentiate three physical mechanisms which can lead to the moisture anomalies: (i) the western and central Himalaya are influenced by extra-tropical Westerlies during winter, (ii) the eastern Himalaya is affected by summer variations of temperature gradient between Bay of Bengal and Indian subcontinent and by a zonal band of intensified Indian-East Asian monsoon link north of 25 degrees N, and (iii) Central India is dominated by summer sea surface temperature anomalies in the northern Arabian Sea which have an effect on the large-scale advection of moist air masses. The temperatures in the Arabian Sea are linked to the Ind Pacific Warm Pool, which modulates the Indian monsoon strength. (C) 2014 The Authors. Published by Elsevier B.V. KW - Medieval Climate Anomaly KW - Little Ice Age KW - moisture variations in India KW - atmosphere-only climate model simulations KW - Lonar Crater Lake KW - multi-proxy reconstructions Y1 - 2014 U6 - https://doi.org/10.1016/j.gloplacha.2014.08.016 SN - 0921-8181 SN - 1872-6364 VL - 122 SP - 176 EP - 185 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Mischke, Steffen A1 - Ashkenazi, Shoshana A1 - Almogi-Labin, Ahuva A1 - Goren-Inbar, Naama T1 - Ostracod evidence for the Acheulian environment of the ancient Hula Lake (Levant) during the early-mid Pleistocene transition JF - Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences N2 - Ostracod shells from the archaeological site Gesher BenotYa'aqov (GBY) in the upper Jordan River Valley (Israel) were investigated to improve the understanding of the environmental conditions of the Acheulian occupation site during the early-mid Pleistocene transition (0.78 Ma). The diverse ostracod assemblage consists of 28 species. The distribution of most of the recorded species in the region today shows that the hydrological conditions at the early-mid Pleistocene transition were not fundamentally different from the modern ones. However, the predominance of Candona neglecta shells in the GBY sequence probably indicates cooler climatic conditions than today. Shells of Candona angulata in the artefact-richer upper half of the sequence suggest a slight salinity increase in the ancient Hula Lake from pure freshwater to slightly oligohaline conditions. This shift probably resulted from wetter conditions and a more stable lake environment with increased residence time of the lake water and stronger influence of evaporation. Shells of the brackish water ostracod Cyprideis torosa and the slightly halophilic Heterocypris sauna and Plesiocypridopsis newtoni were recorded only rarely suggesting that the lake maintained an outlet through the entire period represented by the GBY sequence. Shells of Gomphocythere ortali in GBY cycles 1 and 2 imply that a permanent freshwater stream existed close to the site. Humphcypris subterranea shells in cycles 3-5 provide further evidence that a tributary entered the lake from the south in contrast to the modern setting with the north-south flowing Jordan River at GBY. Statistical analysis of the quantitative ostracod data from GBY identified a group of samples from layers containing more abundant stone artefacts and another group of samples from layers with scarce artefacts. Samples from layers containing more abundant artefacts have relatively high abundances of C. angulata, Darwinula stevensoni and Physocypria kraepelini shells and include rare shells of Ilyocypris hartmanni, Ilyocypris salebrosa, Heterocypris incongniens and Pseudocandona sp. 2 which do not occur in the other samples. The presence of P. kraepelini and H. incongruens shells in artefact-richer sediments possibly indicates poor bottom water oxygenation in the ancient Hula lake sometimes during the periods of Acheulian occupation. However, more detailed studies are required to assess whether lower dissolved oxygen levels in the lake resulted from a slight lake level rise and possibly higher nutrient flux to the lake during wetter conditions or whether hominins already impacted lake's nutrient status by butchering at its shore or by burning of near-shore vegetation. (c) 2014 Elsevier B.V. All rights reserved. KW - Levant KW - Israel KW - Acheulian KW - Lower Palaeolithic KW - Ostracods KW - Palaeoecology Y1 - 2014 U6 - https://doi.org/10.1016/j.palaeo.2014.07.036 SN - 0031-0182 SN - 1872-616X VL - 412 SP - 148 EP - 159 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Konrad-Schmolke, Matthias A1 - Halama, Ralf T1 - Combined thermodynamic-geochemical modeling in metamorphic geology: Boron as tracer of fluid-rock interaction JF - Lithos : an international journal of mineralogy, petrology, and geochemistry N2 - Quantitative geochemical modeling is today applied in a variety of geological environments from the petrogenesis of igneous rocks to radioactive waste disposal. In addition, the development of thermodynamic databases and computer programs to calculate equilibrium phase diagrams has greatly advanced our ability to model geodynamic processes. Combined with experimental data on elemental partitioning and isotopic fractionation, thermodynamic forward modeling unfolds enormous capacities that are far from exhausted. In metamorphic petrology the combination of thermodynamic and trace element forward modeling can be used to study and to quantify processes at spatial scales from mu m to km. The thermodynamic forward models utilize Gibbs energy minimization to quantify mineralogical changes along a reaction path of a chemically open fluid/rock system. These results are combined with mass balanced trace element calculations to determine the trace element distribution between rock and melt/fluid during the metamorphic evolution. Thus, effects of mineral reactions, fluid-rock interaction and element transport in metamorphic rocks on the trace element and isotopic composition of minerals, rocks and percolating fluids or melts can be predicted. Here we illustrate the capacities of combined thermodynamic-geochemical modeling based on two examples relevant to mass transfer during metamorphism. The first example focuses on fluid-rock interaction in and around a blueschist-facies shear zone in felsic gneisses, where fluid-induced mineral reactions and their effects on boron (B) concentrations and isotopic compositions in white mica are modeled. In the second example, fluid release from a subducted slab, the associated transport of B as well as variations in B concentrations and isotopic compositions in liberated fluids and residual rocks are modeled. We compare the modeled results of both examples to geochemical data of natural minerals and rocks and demonstrate that the combination of thermodynamic and geochemical models enables quantification of metamorphic processes and insights into element cycling that would have been unattainable if only one model approach was chosen. (C) 2014 Elsevier B.V. All rights reserved. KW - Thermodynamic-geochemical modeling KW - Fluid-rock interaction KW - Subduction KW - Dehydration KW - Boron isotopes Y1 - 2014 U6 - https://doi.org/10.1016/j.lithos.2014.09.021 SN - 0024-4937 SN - 1872-6143 VL - 208 SP - 393 EP - 414 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Rehman, Hafiz Ur A1 - Tanaka, Ryoji A1 - Kobayashi, Katsura A1 - Tsujimori, Tatsuki A1 - Nakamura, Eizo A1 - Yamamoto, Hiroshi A1 - Khan, Tahseenullah A1 - Kaneko, Yoshiyuki T1 - Oxygen isotopes in Indian Plate eclogites (Kaghan Valley, Pakistan): Negative delta O-18 values from a high latitude protolith reset by Himalayan metamorphism JF - Lithos : an international journal of mineralogy, petrology, and geochemistry N2 - Oxygen isotope compositions are reported for the first time for the Himalayan metabasites of the Kaghan Valley, Pakistan in this study. The highest metamorphic grades are recorded in the north of the valley, near the India-Asia collision boundary, in the form of high-pressure (HP: Group I) and ultrahigh-pressure (UHP: Group II) eclogites. The rocks show a step-wise decrease in grade from the UHP to HP eclogites and amphibolites. The protoliths of these metabasites were the Permian Panjal Trap basalts (ca. 267 +/- 2.4 Ma), which were emplaced along the northern margin of India when it was part of Gondwana. After the break-up of Gondwana, India drifted northward, subducted beneath Asia and underwent UHP metamorphism during the Eocene (ca. 45 +/- 1.2 Ma). At the regional scale, amphibolites, Group I and II eclogites yielded delta O-18 values of +5.84 and +5.91 parts per thousand, +1.66 to +424 parts per thousand, and -2.25 to +0.76 parts per thousand, respectively, relative to VSMOW. On a more local scale, within a single eclogite body, the delta O-18 values were the lowest (-2.25 to-1.44%.) in the central, the best preserved (least retrograded) parts, and show a systematic increase outward into more retrograded rocks, reaching up to +0.12 parts per thousand. These values are significantly lower than the typical mantle values for basalts of + 5.7 +/- 0.3 parts per thousand. The unusually low or negative delta O-18 values in Group II eclogites potentially resulted from hydrothermal alteration of the protoliths by interactions with meteoric water when the Indian plate was at southern high latitudes (similar to 60 degrees S). The stepwise increase in delta O-18 values, among different eclogite bodies in general and at single outcrop-scales in particular, reflects differing degrees of resetting of the oxygen isotope compositions during exhumation-related retrogression. (C) 2014 Elsevier B.V. All rights reserved. KW - Himalaya KW - Kaghan KW - UHP eclogites KW - Oxygen isotope compositions KW - Laser fluorination Y1 - 2014 U6 - https://doi.org/10.1016/j.lithos.2014.09.007 SN - 0024-4937 SN - 1872-6143 VL - 208 SP - 471 EP - 483 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Tu, Rui A1 - Wang, Rongjiang A1 - Walter, Thomas R. A1 - Diao, FaQi T1 - Adaptive recognition and correction of baseline shifts from collocated GPS and accelerometer using two phases Kalman filter JF - Advances in space research N2 - The real-time recognition and precise correction of baseline shifts in strong-motion records is a critical issue for GPS and accelerometer combined processing. This paper proposes a method to adaptively recognize and correct baseline shifts in strong-motion records by utilizing GPS measurements using two phases Kalman filter. By defining four kinds of learning statistics and criteria, the time series of estimated baseline shifts can be divided into four time intervals: initialization, static, transient and permanent. During the time interval in which the transient baseline shift is recognized, the dynamic noise of the Kalman filter system and the length of the baseline shifts estimation window are adaptively adjusted to yield a robust integration solution. The validations from an experimental and real datasets show that acceleration baseline shifts can be precisely recognized and corrected, thus, the combined system adaptively adjusted the estimation strategy to get a more robust solution. (C) 2014 COSPAR. Published by Elsevier Ltd. All rights reserved. KW - GPS KW - Strong-motion KW - Baseline shift KW - Kalman filter KW - Integration Y1 - 2014 U6 - https://doi.org/10.1016/j.asr.2014.07.008 SN - 0273-1177 SN - 1879-1948 VL - 54 IS - 9 SP - 1924 EP - 1932 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Huang, Xiangtong A1 - Oberhaensli, Hedi A1 - von Suchodoletz, Hans A1 - Prasad, Sushma A1 - Sorrel, Philippe A1 - Plessen, Birgit A1 - Mathis, Marie A1 - Usubaliev, Raskul T1 - Hydrological changes in western Central Asia (Kyrgyzstan) during the Holocene as inferred from a palaeolimnological study in lake Son Kul JF - Quaternary science reviews : the international multidisciplinary research and review journal N2 - The hydrology of western Central Asia is highly sensitive to climatic perturbations. In order to understand its long-term variability and to infer linkages between precipitation and atmospheric and oceanic systems, we conducted a thorough sedimentary and geochemical study on a composite core retrieved in lake Son Kul (central Kyrgyzstan). A multi-proxy approach was conducted on lake sediments based on grain size analyses, magnetic susceptibility, total organic carbon (TOC), total nitrogen (TN) and carbon and oxygen isotope analyses on bulk and biogenic materials (ostracoda and molluscs shells) at a resolution equivalent to ca 40 years, aiming to characterise the sequence of palaeolimnological changes in Son Kul. As indicated by delta O-18 record of bulk carbonates, mainly consisting of aragonite, the Holocene hydrological balance was negative during most of time, suggesting an excess of evaporation (E) over precipitation (P). Limnological conditions fluctuated rapidly before 5000 cal yr BP indicating significant changes in regional hydrology and climate. In particular, the long-term negative hydrological balance was impeded by several short stages with marked increase of precipitation, lasting several decades to a few centuries (e.g., 8300-8200, 6900-6700, 6300-6100, 5500-5400, 5300-5200 and 3100 -3000 cal yr BP). Precipitation changes as inferred from 8180 data are also documented by increased minerogenic detritus and higher TOC. We propose that the seasonal pattern of precipitation varied transiently in western Central Asia during the Holocene, although evaporation changes may also account for the rapid changes observed in delta O-18 data. When the annual water balance was less critical (P <= E), the excess of water might be ascribed to increased precipitation during cold seasons mainly because winter precipitation has more negative delta O-18 than its summer equivalent. Conversely, when the annual water balance is negative (P E), the moisture was mainly delivered during the warm season, as between 5000 and 2000 cal yr BP. Our results thus imply that moisture sources could have changed as well during the Holocene. Moisture was delivered as today mainly during summer from the extended Caspian-Aral Basin and eastern Mediterranean, although Arctic and even North Atlantic seas might be important moisture sources when seasonal precipitation was dominated by winter precipitation. We hypothesise that warming Arctic and North Atlantic seas were important for the North Hemisphere circulation during the cold season. (C) 2014 Elsevier Ltd. All rights reserved. KW - Holocene KW - Tien Shan (western Central Asia) KW - Oxygen and carbon isotopes KW - Hydrological balance Y1 - 2014 U6 - https://doi.org/10.1016/j.quascirev.2014.09.012 SN - 0277-3791 VL - 103 SP - 134 EP - 152 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Sachse, Rene A1 - Petzoldt, Thomas A1 - Blumstock, Maria A1 - Moreira, Santiago A1 - Paetzig, Marlene A1 - Ruecker, Jacqueline A1 - Janse, Jan H. A1 - Mooij, Wolf M. A1 - Hilt, Sabine T1 - Extending one-dimensional models for deep lakes to simulate the impact of submerged macrophytes on water quality JF - Environmental modelling & software with environment data news N2 - Submerged macrophytes can stabilise clear water conditions in shallow lakes. However, many existing models for deep lakes neglect their impact. Here, we tested the hypothesis that submerged macrophytes can affect the water clarity in deep lakes. A one-dimensional, vertically resolved macrophyte model was developed based on PCLake and coupled to SALMO-1D and GOTM hydrophysics and validated against field data. Validation showed good coherence in dynamic growth patterns and colonisation depths. In our simulations the presence of submerged macrophytes resulted in up to 50% less phytoplankton biomass in the shallowest simulated lake (11 m) and still 15% less phytoplankton was predicted in 100 m deep oligotrophic lakes. Nutrient loading, lake depth, and lake shape had a strong influence on macrophyte effects. Nutrient competition was found to be the strongest biological interaction. Despite a number of limitations, the derived dynamic lake model suggests significant effects of submerged macrophytes on deep lake water quality. (C) 2014 Elsevier Ltd. All rights reserved. KW - Lake model KW - Macrophytes KW - Water quality Y1 - 2014 U6 - https://doi.org/10.1016/j.envsoft.2014.05.023 SN - 1364-8152 SN - 1873-6726 VL - 61 SP - 410 EP - 423 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Aich, Valentin A1 - Zimmermann, Alexander A1 - Elsenbeer, Helmut T1 - Quantification and interpretation of suspended-sediment discharge hysteresis patterns: How much data do we need? JF - Catena : an interdisciplinary journal of soil science, hydrology, geomorphology focusing on geoecology and landscape evolution N2 - Sediment-discharge hysteresis loops are frequently analyzed to facilitate the understanding of sediment transport processes. Hysteresis patterns, however, are often complex and their interpretation can be complicated. Particularly, quantifying hysteresis patterns remains a problematic issue. Moreover, it is currently unknown how much data is required for analyzing sediment-discharge hysteresis loops in a given area. These open questions and challenges motivated us to develop a new method for quantifying suspended-sediment hysteresis. Subsequently, we applied the new hysteresis index to three suspended-sediment and discharge datasets from a small tropical rainforest catchment. The datasets comprised a different number of events and sampling sites. Our analyses show three main findings: (1) datasets restricted to only few events, which is typical for rapid assessment surveys, were always sufficient to identify the dominating hysteresis pattern in our research area. Furthermore, some of these small datasets contained multiple-peak events that allowed identifying intra-event exhaustion effects and hence, limitations in sediment supply. (2) Datasets comprising complete hydrological years were particularly useful for analyzing seasonal dynamics of hysteresis. These analyses revealed an exhaustion of hysteresis on the inter-event scale which also points to a limited sediment supply. (3) Datasets comprising measurements from two consecutive gauges installed at the catchment outlet and on a slope within that catchment allowed analyzing the change of hysteresis patterns along the flowpath. On the slope, multiple-peak events showed a stronger intra-event exhaustion of hysteresis than at the catchment outlet. Furthermore, exhaustion of hysteresis on the inter-event scale was not evident on the slope but occurred at the catchment outlet. Our results indicate that even small sediment datasets can provide valuable insights into sediment transport processes of small catchments. Furthermore, our results may serve as a first guideline on what to expect from an analysis of hysteresis patterns for datasets of varying quality and quantity. (c) 2014 Elsevier B.V. All rights reserved. KW - Suspended sediment KW - Hysteresis index KW - Sediment monitoring KW - Overland flow KW - Tropical forest Y1 - 2014 U6 - https://doi.org/10.1016/j.catena.2014.06.020 SN - 0341-8162 SN - 1872-6887 VL - 122 SP - 120 EP - 129 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Dulanya, Zuze A1 - Croudace, Ian A1 - Reed, Jane M. A1 - Trauth, Martin H. T1 - Palaeolimnological reconstruction of recent environmental change in Lake Malombe (S. Malawi) using multiple proxies JF - Water SA N2 - Shallow inland water bodies in Malawi continue to be threatened by various environmental challenges despite their importance to the fisheries industry. Due to the complex interaction between natural and anthropogenic disturbances, disentangling the effect of the two may be a complicated process. The littoral zone of most water bodies is important in environmental reconstructions including pollution and lake level monitoring. This study used a littoral zone, transect-based approach employing multi-proxy palaeolimnological techniques to reconstruct recent environmental change (ca. 100 yrs.) in Lake Malombe in the Malawi Rift, East Africa. The results of the study could inform fisheries management in Lake Malombe, which experienced a catastrophic decline in fish stocks. Results support documentary evidence for the complete desiccation of the lake less than 100 years ago. Subsequently, there is evidence for accelerated eutrophication in the recent past. In light of these results, it is concluded that transect sampling approaches rather than relying on single core measurements, and the need for careful consideration of the types of proxy, are significant considerations in palaeoenvironmental reconstructions. KW - littoral zone KW - palaeolimnology KW - diatoms KW - Lake Malombe Y1 - 2014 U6 - https://doi.org/10.4314/wsa.v40i4.17 SN - 0378-4738 SN - 1816-7950 VL - 40 IS - 4 SP - 717 EP - 727 PB - Water Research Commission CY - Pretoria ER - TY - JOUR A1 - Crausbay, Shelley A1 - Genderjahn, Steffi A1 - Hotchkiss, Sara A1 - Sachse, Dirk A1 - Kahmen, Ansgar A1 - Arndt, Stefan K. T1 - Vegetation dynamics at the upper reaches of a tropical montane forest are driven by disturbance over the past 7300 years JF - Arctic, antarctic, and alpine research : an interdisciplinary journal N2 - We assessed tropical montane cloud forest (TMCF) sensitivity to natural disturbance by drought, fire, and dieback with a 7300-year-long paleorecord. We analyzed pollen assemblages, charcoal accumulation rates, and higher plant biomarker compounds (average chain length [ACL] of n-alkanes) in sediments from Wai 'anapanapa, a small lake near the upper forest limit and the mean trade wind inversion ('IWI) in Hawai`i. The paleorecord of ACL suggests increased drought frequency and a lower awl elevation from 2555-1323 cal yr B.P. and 606-334 cal yr B.P. Charcoal began to accumulate and a novel fire regime was initiated ca. 880 cal yr B.P., followed by a decreased fire return interval at ca. 550 cal yr B.P. Diebacks occurred at 2931, 2161, 1162, and 306 cal yr B.P., and two of these were independent of drought or fire. Pollen assemblages indicate that on average species composition changed only 2.8% per decade. These dynamics, though slight, were significantly associated with disturbance. The direction of species composition change varied with disturbance type. Drought was associated with significantly more vines and lianas; fire was associated with an increase in the tree fern Sadleria and indicators of open, disturbed landscapes at the expense of epiphytic ferns; whereas stand-scale dieback was associated with an increase in the tree fern Cibotium. Though this cloud forest was dynamic in response to past disturbance, it has recovered, suggesting a resilient TMCF with no evidence of state change in vegetation type (e.g., grassland or shrubland). Y1 - 2014 U6 - https://doi.org/10.1657/1938-4246-46.4.787 SN - 1523-0430 SN - 1938-4246 VL - 46 IS - 4 SP - 787 EP - 799 PB - Institute of Arctic and Alpine Research, University of Colorado CY - Boulder ER - TY - JOUR A1 - Haßler, Sibylle Kathrin A1 - Lark, R. M. A1 - Zimmermann, Beate A1 - Elsenbeer, Helmut T1 - Which sampling design to monitor saturated hydraulic conductivity? JF - European journal of soil science N2 - Soil in a changing world is subject to both anthropogenic and environmental stresses. Soil monitoring is essential to assess the magnitude of changes in soil variables and how they affect ecosystem processes and human livelihoods. However, we cannot always be sure which sampling design is best for a given monitoring task. We employed a rotational stratified simple random sampling (rotStRS) for the estimation of temporal changes in the spatial mean of saturated hydraulic conductivity (K-s) at three sites in central Panama in 2009, 2010 and 2011. To assess this design's efficiency we compared the resulting estimates of the spatial mean and variance for 2009 with those gained from stratified simple random sampling (StRS), which was effectively the data obtained on the first sampling time, and with an equivalent unexecuted simple random sampling (SRS). The poor performance of geometrical stratification and the weak predictive relationship between measurements of successive years yielded no advantage of sampling designs more complex than SRS. The failure of stratification may be attributed to the small large-scale variability of K-s. Revisiting previously sampled locations was not beneficial because of the large small-scale variability in combination with destructive sampling, resulting in poor consistency between revisited samples. We conclude that for our K-s monitoring scheme, repeated SRS is equally effective as rotStRS. Some problems of small-scale variability might be overcome by collecting several samples at close range to reduce the effect of small-scale variation. Finally, we give recommendations on the key factors to consider when deciding whether to use stratification and rotation in a soil monitoring scheme. Y1 - 2014 U6 - https://doi.org/10.1111/ejss.12174 SN - 1351-0754 SN - 1365-2389 VL - 65 IS - 6 SP - 792 EP - 802 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Hunziker, Matthias A1 - Sigurdsson, Bjarni D. A1 - Halldorsson, Gudmundur A1 - Schwanghart, Wolfgang A1 - Kuhn, Nikolaus T1 - Biomass allometries and coarse root biomass distribution of mountain birch in southern Iceland JF - Icelandic agricultural sciences N2 - Root systems are an important pool of biomass and carbon in forest ecosystems. However, most allometric studies on forest trees focus only on the aboveground components. When estimated, root biomass has most often been calculated by using a fixed conversion factor from aboveground biomass. In order to study the size-related development of the root system of native mountain birch (Betula pubescens Ehrh. ssp. czerepanovii), we collected the coarse root system of 25 different aged birch trees (stem diameter at 50 cm length between 0.2 and 14.1 cm) and characterized them by penetration depth (< 1 m) and root thickness. Based on this dataset, allometric functions for coarse roots (> 5 mm and > 2 mm), root stock, total belowground biomass and aboveground biomass components were calculated by a nonlinear and a linear fitting approach. The study showed that coarse root biomass of mountain birch was almost exclusively (> 95 weight-%) located in the top 30 cm, even in a natural old-growth woodland. By using a cross-validation approach, we found that the nonlinear fitting procedure performed better than the linear approach with respect to predictive power. In addition, our results underscore that general assumptions of fixed conversion factors lead to an underestimation of the belowground biomass. Thus, our results provide allometric functions for a more accurate root biomass estimation to be utilized in inventory reports and ecological studies. KW - mountain birch KW - belowground biomass KW - root depth distribution KW - aboveground biomass KW - Betula pubescens Ehrh. ssp czerepanovii Y1 - 2014 SN - 1670-567X VL - 27 SP - 111 EP - 125 PB - Agricultural University of Iceland CY - Reykjavik ER - TY - JOUR A1 - Li, Shaoyang A1 - Moreno, Marcos A1 - Rosenau, Matthias A1 - Melnick, Daniel A1 - Oncken, Onno T1 - Splay fault triggering by great subduction earthquakes inferred from finite element models JF - Geophysical research letters N2 - We have investigated the influence that megathrust earthquake slip has on the activation of splay faults using a 2-D finite element method (FEM), taking into account the effects of gravity and variations in the frictional strength properties of splay faults. We simulated both landward-dipping and seaward-dipping splay fault geometries, and imposed depth-variable slip distributions of subduction events. Our results indicate that the two types of splay fault exhibit a similar behavior, with variations in frictional properties along the faults affecting only the seismic magnitude. The triggering process is controlled by a critical depth. Megathrust slip concentrated at depths shallower than the critical depth will favor normal displacement, while megathrust slip concentrated at depths deeper than the critical depth is likely to result in reverse motion. Our results thus provide a useful tool for predicting the activation of secondary faults and may have direct implications for tsunami hazard research. KW - earthquake deformation KW - subduction zone earthquakes KW - splay faults KW - faulting behavior KW - FEM models KW - tsunami hazards Y1 - 2014 U6 - https://doi.org/10.1002/2013GL058598 SN - 0094-8276 SN - 1944-8007 VL - 41 IS - 2 SP - 385 EP - 391 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Schwanghart, Wolfgang A1 - Scherler, Dirk T1 - Short Communication: TopoToolbox 2-MATLAB-based software for topographic analysis and modeling in Earth surface sciences JF - Earth surface dynamics N2 - TopoToolbox is a MATLAB program for the analysis of digital elevation models (DEMs). With the release of version 2, the software adopts an object-oriented programming (OOP) approach to work with gridded DEMs and derived data such as flow directions and stream networks. The introduction of a novel technique to store flow directions as topologically ordered vectors of indices enables calculation of flow-related attributes such as flow accumulation similar to 20 times faster than conventional algorithms while at the same time reducing memory overhead to 33% of that required by the previous version. Graphical user interfaces (GUIs) enable visual exploration and interaction with DEMs and derivatives and provide access to tools targeted at fluvial and tectonic geomorphologists. With its new release, TopoToolbox has become a more memory-efficient and faster tool for basic and advanced digital terrain analysis that can be used as a framework for building hydrological and geomorphological models in MATLAB. Y1 - 2014 U6 - https://doi.org/10.5194/esurf-2-1-2014 SN - 2196-6311 SN - 2196-632X VL - 2 IS - 1 SP - 1 EP - 7 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Reiter, Karsten A1 - Heidbach, Oliver T1 - 3-D geomechanical-numerical model of the contemporary crustal stress state in the Alberta Basin (Canada) JF - Solid earth N2 - In the context of examining the potential usage of safe and sustainable geothermal energy in the Alberta Basin, whether in deep sediments or crystalline rock, the understanding of the in situ stress state is crucial. It is a key challenge to estimate the 3-D stress state at an arbitrarily chosen point in the crust, based on sparsely distributed in situ stress data. To address this challenge, we present a large-scale 3-D geomechanical-numerical model (700 km x 1200 km x 80 km) from a large portion of the Alberta Basin, to provide a 3-D continuous quantification of the contemporary stress orientations and stress magnitudes. To calibrate the model, we use a large database of in situ stress orientation (321 S-Hmax) as well as stress magnitude data (981 S-V, 1720 S-hmin and 2 (+11) S-Hmax) from the Alberta Basin. To find the best-fit model, we vary the material properties and primarily the displacement boundary conditions of the model. This study focusses in detail on the statistical calibration procedure, because of the large amount of available data, the diversity of data types, and the importance of the order of data tests. The best-fit model provides the total 3-D stress tensor for nearly the whole Alberta Basin, and allows estimation of stress orientation and stress magnitudes in advance of any well. First-order implications for the well design and configuration of enhanced geothermal systems are revealed. Systematic deviations of the modelled stress from the in situ data are found for stress orientations in the Peace River and the Bow Island Arch as well as for leak-off test magnitudes. Y1 - 2014 U6 - https://doi.org/10.5194/se-5-1123-2014 SN - 1869-9510 SN - 1869-9529 VL - 5 IS - 2 SP - 1123 EP - 1149 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Reiter, Karsten A1 - Heidbach, Oliver A1 - Schmitt, Douglas A1 - Haug, Kristine A1 - Ziegler, Moritz O. A1 - Moeck, Inga T1 - A revised crustal stress orientation database for Canada JF - Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth N2 - The Canadian database on contemporary crustal stress has not been revised systematically in the past two decades. Here we present the results of our new compilation that contains 514 new data records for the orientation data of maximum compressive horizontal stress and 188 data records that were re-assessed. In total the Canadian stress database has now 1667 data records, which is an increase of about 45%. From these data, a new Canadian Stress map as well as one for the Province of Alberta is presented. To analyse the stress pattern, we use the quasi median on the circle as a smoothing algorithm that generates a smoothed stress map of the maximum compressive horizontal stress orientation on a regular grid. The newly introduced quasi interquartile range on the circle estimates the spreading of the data and is used as a measure for the wave-length of the stress pattern. The result of the hybrid wavelength analysis confirms that long spatial wavelength stress patterns (>= 1000 km) exist in large areas in Canada. The observed stress pattern is transmitted through the intra-plate regions. The results reveal that shorter spatial wave length variation of the maximum compressive horizontal stress orientation of less than 200 km, prevails particularly in south-eastern and western Canada. Regional stress sources such as density contrasts, active fault systems, crustal structures, etc. might have a significant impact in these regions. In contrast to these variations, the observed stress pattern in the Alberta Basin is very homogeneous and mainly controlled by plate boundary forces and body forces. The influence of curvature of the Rocky Mountains salient in southern Alberta is minimal. The present-day horizontal stress orientations determined herein have important implications for the production of hydrocarbons and geothermal energy in the Alberta Basin. (C) 2014 Elsevier B.V. All rights reserved. KW - Stress pattern KW - Tectonic stress KW - Canada KW - Alberta KW - Database KW - Circular statistics Y1 - 2014 U6 - https://doi.org/10.1016/j.tecto.2014.08.006 SN - 0040-1951 SN - 1879-3266 VL - 636 SP - 111 EP - 124 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Vales, Dina A1 - Dias, Nuno A. A1 - Rio, Ines A1 - Matias, Luis A1 - Silveira, Graca A1 - Madeira, Jose A1 - Weber, Michael H. A1 - Carrilho, Fernando A1 - Haberland, Christian T1 - Intraplate seismicity across the Cape Verde swell: A contribution from a temporary seismic network JF - Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth N2 - We present an analysis and characterization of the regional seismicity recorded by a temporary broadband seismic network deployed in the Cape Verde archipelago between November 2007 and September 2008. The detection of earthquakes was based on spectrograms, allowing the discrimination from low-frequency volcanic signals, resulting in 358 events of which 265 were located, the magnitudes usually being smaller than 3. For the location, a new 1-D P-velocity model was derived for the region showing a crust consistent with an oceanic crustal structure. The seismicity is located mostly offshore the westernmost and geologically youngest areas of the archipelago, near the islands of Santo Antao and Sao Vicente in the NW and Brava and Fogo in the SW. The SW cluster has a lower occurrence rate and corresponds to seismicity concentrated mainly along an alignment between Brava and the Cadamosto seamount presenting normal faulting mechanisms. The existence of the NW cluster, located offshore SW of Santo Antao, was so far unknown and concentrates around a recently recognized submarine cone field; this cluster presents focal depths extending from the crust to the upper mantle and suggests volcanic unrest No evident temporal behaviour could be perceived, although the events tend to occur in bursts of activity lasting a few days. In this recording period, no significant activity was detected at Fogo volcano, the most active volcanic edifice in Cape Verde. The seismicity characteristics point mainly to a volcanic origin. The correlation of the recorded seismicity with active volcanic structures agrees with the tendency for a westward migration of volcanic activity in the archipelago as indicated by the geologic record. (C) 2014 Elsevier B.V. All rights reserved. KW - Intraplate seismicity KW - Clustering KW - Local magnitude scale KW - Active volcanism KW - Cape Verde KW - Atlantic Ocean Y1 - 2014 U6 - https://doi.org/10.1016/j.tecto.2014.09.014 SN - 0040-1951 SN - 1879-3266 VL - 636 SP - 325 EP - 337 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Pourteau, Amaury A1 - Bousquet, Romain A1 - Vidal, Olivier A1 - Plunder, Alexis A1 - Duesterhoeft, Erik A1 - Candan, Osman A1 - Oberhänsli, Roland T1 - Multistage growth of Fe-Mg-carpholite and Fe-Mg-chloritoid, from field evidence to thermodynamic modelling JF - Contributions to mineralogy and petrology N2 - We provide new insights into the prograde evolution of HP/LT metasedimentary rocks on the basis of detailed petrologic examination, element-partitioning analysis, and thermodynamic modelling of well-preserved Fe-Mg-carpholite- and Fe-Mg-chloritoid-bearing rocks from the Afyon Zone (Anatolia). We document continuous and discontinuous compositional (ferromagnesian substitution) zoning of carpholite (overall X-Mg = 0.27-0.73) and chloritoid (overall X-Mg = 0.07-0.30), as well as clear equilibrium and disequilibrium (i.e., reaction-related) textures involving carpholite and chloritoid, which consistently account for the consistent enrichment in Mg of both minerals through time, and the progressive replacement of carpholite by chloritoid. Mg/Fe distribution coefficients calculated between carpholite and chloritoid vary widely within samples (2.2-20.0). Among this range, only values of 7-11 correlate with equilibrium textures, in agreement with data from the literature. Equilibrium phase diagrams for metapelitic compositions are calculated using a newly modified thermodynamic dataset, including most recent data for carpholite, chloritoid, chlorite, and white mica, as well as further refinements for Fe-carpholite, and both chloritoid end-members, as required to reproduce accurately petrologic observations (phase relations, experimental constraints, Mg/Fe partitioning). Modelling reveals that Mg/Fe partitioning between carpholite and chloritoid is greatly sensitive to temperature and calls for a future evaluation of possible use as a thermometer. In addition, calculations show significant effective bulk composition changes during prograde metamorphism due to the fractionation of chloritoid formed at the expense of carpholite. We retrieve P-T conditions for several carpholite and chloritoid growth stages (1) during prograde stages using unfractionated, bulk-rock XRF analyses, and (2) at peak conditions using compositions fractionated for chloritoid. The P-T paths reconstructed for the Kutahya and Afyon areas shed light on contrasting temperature conditions for these areas during prograde and peak stages. KW - HP/LT metamorphism KW - Carpholite KW - Chloritoid KW - Growth zoning KW - Element partitioning KW - Chemical fractionation Y1 - 2014 U6 - https://doi.org/10.1007/s00410-014-1090-7 SN - 0010-7999 SN - 1432-0967 VL - 168 IS - 6 PB - Springer CY - New York ER - TY - JOUR A1 - Wang, Ping A1 - Scherler, Dirk A1 - Jing Liu-Zeng, A1 - Mey, Jürgen A1 - Avouac, Jean-Philippe A1 - Zhang, Yunda A1 - Shi, Dingguo T1 - Tectonic control of Yarlung Tsangpo Gorge revealed by a buried canyon in Southern Tibet JF - Science N2 - The Himalayan mountains are dissected by some of the deepest and most impressive gorges on Earth. Constraining the interplay between river incision and rock uplift is important for understanding tectonic deformation in this region. We report here the discovery of a deeply incised canyon of the Yarlung Tsangpo River, at the eastern end of the Himalaya, which is now buried under more than 500 meters of sediments. By reconstructing the former valley bottom and dating sediments at the base of the valley fill, we show that steepening of the Tsangpo Gorge started at about 2 million to 2.5 million years ago as a consequence of an increase in rock uplift rates. The high erosion rates within the gorge are therefore a direct consequence of rapid rock uplift. Y1 - 2014 U6 - https://doi.org/10.1126/science.1259041 SN - 0036-8075 SN - 1095-9203 VL - 346 IS - 6212 SP - 978 EP - 981 PB - American Assoc. for the Advancement of Science CY - Washington ER - TY - JOUR A1 - Noah, Mareike A1 - Lappe, Michael A1 - Schneider, Beate A1 - Vieth-Hillebrand, Andrea A1 - Wilkes, Heinz A1 - Kallmeyer, Jens T1 - Tracing biogeochemical and microbial variability over a complete oil sand mining and recultivation process JF - The science of the total environment : an international journal for scientific research into the environment and its relationship with man N2 - Recultivation of disturbed oil sand mining areas is an issue of increasing importance. Nevertheless only little is known about the fate of organic matter, cell abundances and microbial community structures during oil sand processing, tailings management and initial soil development on reclamation sites. Thus the focus of this work is on biogeochemical changes of mined oil sands through the entire process chain until its use as substratum for newly developing soils on reclamation sites. Therefore, oil sand, mature fine tailings (MFTs) from tailings ponds and drying cells and tailings sand covered with peat-mineral mix (PMM) as part of land reclamation were analyzed. The sample set was selected to address the question whether changes in the above-mentioned biogeochemical parameters can be related to oil sand processing or biological processes and how these changes influence microbial activities and soil development. GC-MS analyses of oil-derived biomarkers reveal that these compounds remain unaffected by oil sand processing and biological activity. In contrast, changes in polycyclic aromatic hydrocarbon (PAH) abundance and pattern can be observed along the process chain. Especially naphthalenes, phenanthrenes and chrysenes are altered or absent on reclamation sites, Furthermore, root-bearing horizons on reclamation sites exhibit cell abundances at least ten times higher (10(8) to 10(9) cells g(-1)) than in oil sand and MFF samples (10(7) cells g(-1)) and show a higher diversity in their microbial community structure. Nitrate in the pore water and roots derived from the PMM seem to be the most important stimulants for microbial growth. The combined data show that the observed compositional changes are mostly related to biological activity and the addition of exogenous organic components (PMM), whereas oil extraction, tailings dewatering and compaction do not have significant influences on the evaluated compounds. Microbial community composition remains relatively stable through the entire process chain. (C) 2014 Elsevier B.V. All rights reserved. KW - Oil sands KW - Tailings ponds KW - Reclamation KW - PAN KW - Biomarker KW - Microbial community analysis Y1 - 2014 U6 - https://doi.org/10.1016/j.scitotenv.2014.08.020 SN - 0048-9697 SN - 1879-1026 VL - 499 SP - 297 EP - 310 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Mishrat, Praveen K. A1 - Anoop, A. A1 - Jehangir, A. A1 - Prasad, Sushma A1 - Menze, R. A1 - Schettler, Georg A1 - Naumann, R. A1 - Weise, S. A1 - Andersen, N. A1 - Yousuf, A. R. A1 - Gaye, Birgit T1 - Limnology and modern sedimentation patterns in high altitude Tso Moriri Lake, NW Himalaya - implications for proxy development JF - Fundamental and applied limnology : official journal of the International Association of Theoretical and Applied Limnology N2 - We report the results of our investigations on the catchment area, lake surface sediments, and hydrology of the high altitude alpine Tso Moriri Lake, NW Himalayas (India). Our results indicate that the lake is currently alkaline, and thermally stratified with an oxic bottom layer. Results from hydrochemistry and isotopic composition (delta O-18 and delta D) of inflowing streams and lake waters show that Tso Moriri Lake is an evaporative lake with contributions from both westerly source (snow melt) and Indian summer monsoon precipitation. Geochemical and mineralogical investigations on the catchment and lake surface sediments reveal the presence of authigenic aragonite in modern lake sediment. The lithogenic components reflect the inflow and sorting processes during transport into the lake, whereas the authigenic carbonate fraction can be linked to the changes in ([precipitation+meltwater]/evaporation) (I/E) balance within the lake. The spatial variability in grain size distribution within the lake surface sediments shows that the grain size data can be utilised as a proxy for transport energy and shoreline proximity in the lake basin. We have evaluated the applicability of commonly applied environmentally sensitive proxies (isotopes, mineralogy, weathering indices) for palaeoenvironmental reconstruction in the Tso Moriri Lake. Our results show that the commonly used weathering index (Rb/Sr) is not applicable due to Sr contribution from authigenic carbonates. The useful weathering indices in Tso Moriri Lake are the Si/Al and the Chemical Proxy of Alteration (CPA). Since the carbonates are formed by evaporative processes, their presence and isotopic values can be used as indicators of I/E changes in the lake. KW - geochemistry KW - lake sediments KW - palaeoenvironmental proxies KW - Tso Moriri Lake KW - weathering indices Y1 - 2014 U6 - https://doi.org/10.1127/fal/2014/0664 SN - 1863-9135 VL - 185 IS - 3-4 SP - 329 EP - 348 PB - Schweizerbart CY - Stuttgart ER - TY - JOUR A1 - Craddock, William H. A1 - Kirby, Eric A1 - Zhang, Huiping A1 - Clark, Marin K. A1 - Champagnac, Jean-Daniel A1 - Yuan, Daoyang T1 - Rates and style of Cenozoic deformation around the Gonghe Basin, northeastern Tibetan Plateau JF - Geosphere N2 - The northeastern Tibetan Plateau constitutes a transitional region between the low-relief physiographic plateau to the south and the high-relief ranges of the Qilian Shan to the north. Cenozoic deformation across this margin of the plateau is associated with localized growth of fault-cored mountain ranges and associated basins. Herein, we combine detailed structural analysis of the geometry of range-bounding faults and deformation of foreland basin strata with geomorphic and exhumational records of erosion in hangingwall ranges in order to investigate the magnitude, timing, and style of deformation along the two primary fault systems, the Qinghai Nan Shan and the Gonghe Nan Shan. Structural mapping shows that both ranges have developed above imbricate fans of listric thrust faults, which sole into decollements in the middle crust. Restoration of shortening along balanced cross sections suggests a minimum of 0.8-2.2 km and 5.1-6.9 km of shortening, respectively. Growth strata in the associated foreland basin record the onset of deformation on the two fault systems at ca. 6-10 Ma and ca. 7-10 Ma, respectively, and thus our analysis suggests late Cenozoic shortening rates of 0.2 +0.2/-0.1 km/m.y. and 0.7 +0.3/-0.2 km/m.y. along the north and south sides of Gonghe Basin. Along the Qinghai Nan Shan, these rates are similar to late Pleistocene slip rates of similar to 0.10 +/- 0.04 mm/yr, derived from restoration and dating of a deformed alluvial-fan surface. Collectively, our results imply that deformation along both flanks of the doubly vergent Qilian Shan-Nan Shan initiated by ca. 10 Ma and that subsequent shortening has been relatively steady since that time. Y1 - 2014 U6 - https://doi.org/10.1130/GES01024.1 SN - 1553-040X VL - 10 IS - 6 SP - 1255 EP - 1282 PB - Geological Society of America CY - Boulder ER - TY - INPR A1 - Rehman, Hafiz Ur A1 - Tsujimori, Tatsuki A1 - Okamoto, Kazuaki A1 - Spengler, Dirk T1 - Petrogenesis and chemogenesis of oceanic and continental orogens in Asia: Current topics, Part I Preface T2 - The island arc Y1 - 2014 U6 - https://doi.org/10.1111/iar.12097 SN - 1038-4871 SN - 1440-1738 VL - 23 IS - 4 SP - 251 EP - 253 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Böttcher, Steven A1 - Merz, Christoph A1 - Lischeid, Gunnar A1 - Dannowski, Ralf T1 - Using Isomap to differentiate between anthropogenic and natural effects on groundwater dynamics in a complex geological setting JF - Journal of hydrology N2 - Due to increasing demands and competition for high quality groundwater resources in many parts of the world, there is an urgent need for efficient methods that shed light on the interplay between complex natural settings and anthropogenic impacts. Thus a new approach is introduced, that aims to identify and quantify the predominant processes or factors of influence that drive groundwater and lake water dynamics on a catchment scale. The approach involves a non-linear dimension reduction method called Isometric feature mapping (Isomap). This method is applied to time series of groundwater head and lake water level data from a complex geological setting in Northeastern Germany. Two factors explaining more than 95% of the observed spatial variations are identified: (1) the anthropogenic impact of a waterworks in the study area and (2) natural groundwater recharge with different degrees of dampening at the respective sites of observation. The approach enables a presumption-free assessment to be made of the existing geological conception in the catchment, leading to an extension of the conception. Previously unknown hydraulic connections between two aquifers are identified, and connections revealed between surface water bodies and groundwater. (C) 2014 Elsevier B.V. All rights reserved. KW - Groundwater KW - Lake KW - Interaction KW - Isometric feature mapping KW - Time series analysis Y1 - 2014 U6 - https://doi.org/10.1016/j.jhydrol.2014.09.048 SN - 0022-1694 SN - 1879-2707 VL - 519 SP - 1634 EP - 1641 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Ferrero, Silvio A1 - Braga, R. A1 - Berkesi, M. A1 - Cesare, Bernardo A1 - Ouazaa, N. Laridhi T1 - Production of metaluminous melt during fluid-present anatexis: an example from the Maghrebian basement, La Galite Archipelago, central Mediterranean JF - Journal of metamorphic geology N2 - Garnet brought to the surface by late Miocene granitoids at La Galite Archipelago (Central Mediterranean, Tunisia) contains abundant primary melt and fluid inclusions. Microstructural observations and mineral chemistry define the host garnet as a peritectic phase produced by biotite incongruent melting at ~800 degrees C and 0.5GPa, under fluid-present conditions. The trapped melt is leucogranitic with an unexpected metaluminous and almost peralkaline character. Fluid inclusions are one phase at room temperature, and contain a CO2-dominated fluid, with minor H2O, N-2 and CH4. Siderite and an OH-bearing phase were identified by Raman and IR spectroscopy within every analysed inclusion, and are interpreted as products of a post-entrapment carbonation/hydration reaction between the fluid and the host during cooling. The fluid present during anatexis is therefore inferred to have been originally richer in both H2O and CO2. The production of anatectic melt with a metaluminous signature can be explained as the result of partial melting of relatively Al-poor protoliths assisted by CO2-rich fluids. KW - fluid inclusions KW - garnet KW - anatexis KW - nanogranites KW - melt inclusions Y1 - 2014 U6 - https://doi.org/10.1111/jmg.12068 SN - 0263-4929 SN - 1525-1314 VL - 32 IS - 2 SP - 209 EP - 225 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Deplazes, Gaudenz A1 - Lückge, Andreas A1 - Stuut, Jan-Berend W. A1 - Paetzold, Jürgen A1 - Kuhlmann, Holger A1 - Husson, Dorothee A1 - Fant, Mara A1 - Haug, Gerald H. T1 - Weakening and strengthening of the Indian monsoon during Heinrich events and Dansgaard- Oeschger oscillations JF - Paleoceanography N2 - The Dansgaard-Oeschger oscillations and Heinrich events described in North Atlantic sediments and Greenland ice are expressed in the climate of the tropics, for example, as documented in Arabian Sea sediments. Given the strength of this teleconnection, we seek to reconstruct its range of environmental impacts. We present geochemical and sedimentological data from core SO130-289KL from the Indus submarine slope spanning the last similar to 80 kyr. Elemental and grain size analyses consistently indicate that interstadials are characterized by an increased contribution of fluvial suspension from the Indus River. In contrast, stadials are characterized by an increased contribution of aeolian dust from the Arabian Peninsula. Decadal-scale shifts at climate transitions, such as onsets of interstadials, were coeval with changes in productivity-related proxies. Heinrich events stand out as especially dry and dusty events, indicating a dramatically weakened Indian summer monsoon, potentially increased winter monsoon circulation, and increased aridity on the Arabian Peninsula. This finding is consistent with other paleoclimate evidence for continental aridity in the northern tropics during these events. Our results strengthen the evidence that circum-North Atlantic temperature variations translate to hydrological shifts in the tropics, with major impacts on regional environmental conditions such as rainfall, river discharge, aeolian dust transport, and ocean margin anoxia. KW - Indian Monsoon KW - Arabian Sea KW - XRF KW - Dansgaard-Oeschger oscillations KW - Heinrich events KW - Sediment Transport Y1 - 2014 U6 - https://doi.org/10.1002/2013PA002509 SN - 0883-8305 SN - 1944-9186 VL - 29 IS - 2 SP - 99 EP - 114 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Hermkes, Marcel A1 - Kühn, Nicolas M. A1 - Riggelsen, Carsten T1 - Simultaneous quantification of epistemic and aleatory uncertainty in GMPEs using Gaussian process regression JF - Bulletin of earthquake engineering : official publication of the European Association for Earthquake Engineering N2 - This paper presents a Bayesian non-parametric method based on Gaussian Process (GP) regression to derive ground-motion models for peak-ground parameters and response spectral ordinates. Due to its non-parametric nature there is no need to specify any fixed functional form as in parametric regression models. A GP defines a distribution over functions, which implicitly expresses the uncertainty over the underlying data generating process. An advantage of GP regression is that it is possible to capture the whole uncertainty involved in ground-motion modeling, both in terms of aleatory variability as well as epistemic uncertainty associated with the underlying functional form and data coverage. The distribution over functions is updated in a Bayesian way by computing the posterior distribution of the GP after observing ground-motion data, which in turn can be used to make predictions. The proposed GP regression models is evaluated on a subset of the RESORCE data base for the SIGMA project. The experiments show that GP models have a better generalization error than a simple parametric regression model. A visual assessment of different scenarios demonstrates that the inferred GP models are physically plausible. KW - Gaussian Process regression KW - Epistemic uncertainty KW - Aleatory variability KW - Empirical ground-motion models KW - Bayesian non-parametrics KW - GMPE KW - Generalization error Y1 - 2014 U6 - https://doi.org/10.1007/s10518-013-9507-7 SN - 1570-761X SN - 1573-1456 VL - 12 IS - 1 SP - 449 EP - 466 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Serno, Sascha A1 - Winckler, Gisela A1 - Anderson, Robert F. A1 - Hayes, Christopher T. A1 - McGee, David A1 - Machalett, Bjoern A1 - Ren, Haojia A1 - Straub, Susanne M. A1 - Gersonde, Rainer A1 - Haug, Gerald H. T1 - Eolian dust input to the Subarctic North Pacific JF - Earth & planetary science letters N2 - Eolian dust is a significant source of iron and other nutrients that are essential for the health of marine ecosystems and potentially a controlling factor of the high nutrient-low chlorophyll status of the Subarctic North Pacific. We map the spatial distribution of dust input using three different geochemical tracers of eolian dust, He-4, Th-232 and rare earth elements, in combination with grain size distribution data, from a set of core-top sediments covering the entire Subarctic North Pacific. Using the suite of geochemical proxies to fingerprint different lithogenic components, we deconvolve eolian dust input from other lithogenic inputs such as volcanic ash, ice-rafted debris, riverine and hemipelagic input. While the open ocean sites far away from the volcanic arcs are dominantly composed of pure eolian dust, lithogenic components other than eolian dust play a more crucial role along the arcs. In sites dominated by dust, eolian dust input appears to be characterized by a nearly uniform grain size mode at similar to 4 mu m. Applying the Th-230-normalization technique, our proxies yield a consistent pattern of uniform dust fluxes of 1-2 g/m(2)/yr across the Subarctic North Pacific. Elevated eolian dust fluxes of 2-4 g/m(2)/yr characterize the westernmost region off Japan and the southern Kurile Islands south of 45 degrees N and west of 165 degrees E along the main pathway of the westerly winds. The core-top based dust flux reconstruction is consistent with recent estimates based on dissolved thorium isotope concentrations in seawater from the Subarctic North Pacific. The dust flux pattern compares well with state-of-the-art dust model predictions in the western and central Subarctic North Pacific, but we find that dust fluxes are higher than modeled fluxes by 0.5-1 g/m(2)/yr in the northwest, northeast and eastern Subarctic North Pacific. Our results provide an important benchmark for biogeochemical models and a robust approach for downcore studies testing dust-induced iron fertilization of past changes in biological productivity in the Subarctic North Pacific. KW - eolian dust KW - Subarctic North Pacific KW - INOPEX KW - helium-4 KW - Th-232 KW - REE Y1 - 2014 U6 - https://doi.org/10.1016/j.epsl.2013.11.008 SN - 0012-821X SN - 1385-013X VL - 387 SP - 252 EP - 263 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Rach, Oliver A1 - Brauer, Achim A1 - Wilkes, Heinz A1 - Sachse, Dirk T1 - Delayed hydrological response to Greenland cooling at the onset of the Younger Dryas in western Europe JF - Nature geoscience N2 - The general warming trend of the last deglaciation was interrupted by the Younger Dryas, a period of abrupt cooling and widespread environmental change(1-10). Ice core records suggest the abrupt cooling began 12,846 years ago in Greenland(10), about 170 years before the significant environmental and vegetation change in western Europe(7) classically defined as the Younger Dryas. However, this difference in timing falls within age model uncertainties. Here we use the hydrogen isotope composition of lipid biomarkers from precisely dated varved sediments from Lake Meerfelder Maar to reconstruct hydroclimate over western Europe. We observe a decrease in the hydrogen isotope values of both aquatic and terrestrial lipids 12,850 years ago, indicating cooling climate in this region synchronous with the abrupt cooling in Greenland. A second drop occurs 170 years later, mainly in the hydrogen isotope record of aquatic lipids but to a lesser extent in the terrestrial lipids, which we attribute to aridification, as well as a change in moisture source and pathway. We thus confirm that there was indeed a lag between cooling and substantial hydrologic and environmental change in western Europe. We suggest the delay is related to the expansion of sea ice in the North Atlantic Ocean and the subsequent southward migration of the westerly wind system(9). We further suggest that these hydrological changes amplified environmental change in western Europe at the onset of the Younger Dryas. Y1 - 2014 U6 - https://doi.org/10.1038/NGEO2053 SN - 1752-0894 SN - 1752-0908 VL - 7 IS - 2 SP - 109 EP - 112 PB - Nature Publ. Group CY - New York ER - TY - JOUR A1 - Mischke, Steffen A1 - Lai, Zhongping A1 - Zhang, Chengjun T1 - Re-assessment of the paleoclimate implications of the Shell Bar in the Qaidam Basin, China JF - Journal of paleolimnolog N2 - The Shell Bar in the Qaidam Basin, China, is a prominent geological feature composed of millions of densely packed Corbicula shells. Since the mid 1980s, it has been regarded as evidence for existence of a large lake during Marine Isotope Stage (MIS) 3 in the presently hyper-arid Qaidam Basin. Early studies suggested the bivalve shells accumulated at the shore of a large lake, whereas more recent work led to the conclusion that the Shell Bar was formed within a deeper water body. Based on our re-assessment of sediments and fossils from the Shell Bar, investigation of exposed fluvio-lacustrine sections upstream of the Shell Bar and study of nearby modern streams, we infer that the Shell Bar represents a stream deposit. Corbicula is a typical stream-dweller around the world. Preservation of Corbicula shells of different sizes, as well as occurrence of many articulated shells, provide evidence against post-mortem transport and accumulation along a lake shore. Additionally, the SE-NW alignment of the Shell Bar is similar to modern intermittent stream beds in its vicinity and corresponds to the present-day slope towards the basin centre further NW, and furthermore, the predominantly sandy sediments also indicate that the Shell Bar was formed in a stream. Abundant ostracod shells in the Shell Bar sediments originated from stream-dwelling species that are abundant in modern streams in the vicinity of the Shell Bar, or in part from fluvio-lacustrine sediments exposed upstream of the Shell Bar, as a result of erosion and re-deposition. Deflation of alluvial fine-grained sediments in the Shell Bar region and protection of the stream deposits by the large and thick-walled Corbicula shells reversed the former channel relief and yielded the modern exposure, which is a prominent morphological feature. Occurrence of Corbicula shells in the Qaidam Basin indicates climate was apparently warmer than present during the formation of the Shell Bar because Corbicula does not live at similar or higher altitudes in the region today. Because the Shell Bar is no longer considered a deposit formed within a lake, its presence does not indicate paleoclimate conditions wetter than today. KW - Qaidam Basin KW - Tibetan Plateau KW - Late Pleistocene KW - Corbicula KW - Ostracoda KW - Taphonomy Y1 - 2014 U6 - https://doi.org/10.1007/s10933-012-9674-6 SN - 0921-2728 SN - 1573-0417 VL - 51 IS - 2 SP - 179 EP - 195 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Lai, ZhongPing A1 - Mischke, Steffen A1 - Madsen, David T1 - Paleoenvironmental implications of new OSL dates on the formation of the "Shell Bar" in the Qaidam Basin, northeastern Qinghai-Tibetan Plateau JF - Journal of paleolimnolog N2 - A geological feature in the Qaidam Basin known as the "Shell Bar" contains millions of freshwater clam shells buried in situ. Since the 1980s, this feature in the now hyper-arid basin has been interpreted to be lake deposits that provide evidence for a warmer and more humid climate than present during late marine isotope stage 3 (MIS 3). Global climate during late MIS 3 and the last glacial maximum, however, was cold and dry, with much lower sea levels. We re-investigated the feature geomorphologically and sedimentologically, and employed optically stimulated luminescence (OSL) dating to verify the chronology of the sediments. We interpret the Shell Bar to be a remnant of a river channel formed by a stream that ran across an exposed lake bed during a regressive lake phase. Deflation of the surrounding older, fine-grained lacustrine deposits has left the fluvial channel sediments topographically inverted, indicating the erosive nature of the landscape. Luminescence ages place the formation of the Shell Bar in MIS 5 (similar to 113-99 ka), much older than previous radiocarbon ages of < 40 ka BP, but place the paleoclimatic inferences more in accord with other regional and global climate proxy records. We present a brief review of the age differences derived from C-14 and OSL dating of some critical sections that were thought to represent a warmer and more humid climate than present during late MIS 3. We attribute the differences to underestimation of C-14 ages. We suggest that C-14 ages older than similar to 25 ka BP may require re-investigation, especially dates on samples from arid regions. KW - OSL dating KW - Depositional origin KW - Paleoenvironmental change KW - Late Pleistocene KW - Shell Bar KW - Qaidam Basin KW - Qinghai-Tibetan Plateau (QTP) Y1 - 2014 U6 - https://doi.org/10.1007/s10933-013-9710-1 SN - 0921-2728 SN - 1573-0417 VL - 51 IS - 2 SP - 197 EP - 210 PB - Springer CY - Dordrecht ER - TY - INPR A1 - Lasaponara, Rosa A1 - Murgante, Beniamino A1 - Masini, Nicola A1 - Ge, Yong A1 - Asche, Hartmut T1 - Advance in geocomputation T2 - International journal of applied earth observation and geoinformation Y1 - 2014 U6 - https://doi.org/10.1016/j.jag.2013.10.004 SN - 0303-2434 VL - 26 SP - 429 EP - 431 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Junginger, Annett A1 - Roller, Sybille A1 - Olaka, Lydia A. A1 - Trauth, Martin H. T1 - The effects of solar irradiation changes on the migration of the Congo Air Boundary and water levels of paleo-Lake Suguta, Northern Kenya Rift, during the African Humid Period (15-5 ka BP) JF - Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences N2 - The water-level record from the 300 m deep paleo-lake Suguta (Northern Kenya Rift) during the African Humid Period (AHP, 15-5 ka BP) helps to explain decadal to centennial intensity variations in the West African Monsoon (WAM) and the Indian Summer Monsoon (ISM). This water-level record was derived from three different sources: (1) grain size variations in radiocarbon dated and reservoir corrected lacustrine sediments, (2) the altitudes and ages of paleo-shorelines within the basin, and (3) the results of hydro-balance modeling, providing important insights into the character of water level variations (abrupt or gradual) in the amplifier paleo-Lake Suguta. The results of these comprehensive analyses suggest that the AHP highstand in the Suguta Valley was the direct consequence of a northeastwards shift in the Congo Air Boundary (CAB), which was in turn caused by an enhanced atmospheric pressure gradient between East Africa and India during a northern hemisphere insolation maximum. Rapidly decreasing water levels of up to 90 m over less than a hundred years are best explained by changes in solar irradiation either reducing the East African-Indian atmospheric pressure gradient and preventing the CAB from reaching the study area, or reducing the overall humidity in the atmosphere, or a combination of both these effects. In contrast, although not well documented in our record we hypothesize a gradual end of the AHP despite an abrupt change in the source of precipitation when a decreasing pressure gradient between Asia and Africa prevented the CAB from reaching the Suguta Valley. The abruptness was probably buffered by a contemporaneous change in precession producing an insolation maximum at the equator during October. Whether or not this is the case, the water-level record from the Suguta Valley demonstrates the importance of both orbitally-controlled insolation variations and short-term changes in solar irradiation as factors affecting the significant water level variations in East African rift lakes. KW - East African Rift System KW - Suguta Valley KW - African Humid Period KW - Congo Air Boundary Y1 - 2014 U6 - https://doi.org/10.1016/j.palaeo.2013.12.007 SN - 0031-0182 SN - 1872-616X VL - 396 SP - 1 EP - 16 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Lev, L. A1 - Almogi-Labin, Ahuva A1 - Mischke, Steffen A1 - Ito, E. A1 - Ben-Avraham, Zvi A1 - Stein, M. T1 - Paleohydrology of Lake Kinneret during the Heinrich event H2 JF - Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences N2 - During the last glacial period lake Kinneret (the Sea of Galilee) fluctuated between high and low water levels reflecting the hydrological conditions of the lake watershed. Here, we focus on the hydrology of the lake after its retreat from the last glacial MIS2 (similar to 27-25 ka BP) highest stand of similar to 170 m below mean sea level (m bsl) to the low stand of similar to 214 m bsl at similar to 24-21 ka BP. The limnological-hydrological history of this time interval is recovered from trench and borehole that were dug and drilled in the southwestern shore of the lake at Ohalo-II archeological site. Cyprideis torosa (Ostracoda) recovered from the trench yielded elemental, Sr-87/Sr-86 and delta O-18 isotope data that provide information on the shore environment during the low stand period. The Sr-87/Sr-86 and Sr/Ca ratios in the ostracods, varying between similar to 0.70789 and similar to 0.70815 and 0.0017 and 0.0030, respectively indicate contributions of waters from the last glacial lake and regional runoff. The increase in the Sr-87/Sr-86 ratios reflects the decreasing effect of the last glacial Lake Kinneret waters and enhanced contribution of local runoff that washed down dried mountain soils that were previously developed during the wet and vegetated glacial. The lake retreat at similar to 24 ka BP coincided with the Heinrich event H2 at the northern Atlantic. H2 was expressed by severe aridity in Lake Kinneret-Dead Sea watershed. The limnological-hydrological change at post H2 was accompanied by 2% decrease in the delta O-18 value from -2% to -4% reflecting the change in the composition of the east Mediterranean rain sources. The last glacial lake Sr-87/Sr-86 ratio is similar to the Tiberias Spa saline waters and distinctly different from the modern Lake Kinneret fresh waters: Sr-87/Sr-86 similar to 0.70785 compared to similar to 0.70760, respectively. This difference is explained by enhanced contribution of Ca-chloride brines with high Sr-87/Sr-86 values to the last glacial lake and reduced Jordan River contribution due to cold freezing conditions at its headwaters, while the modern Lake Kinneret is more affected by low Sr-87/Sr-86 freshwater from the Jordan watershed. KW - Ostracods KW - Lake Kinneret KW - Paleolimnology KW - Paleohydrology KW - Sr-87/Sr-86 KW - delta O-18 Y1 - 2014 U6 - https://doi.org/10.1016/j.palaeo.2014.01.005 SN - 0031-0182 SN - 1872-616X VL - 396 SP - 183 EP - 193 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Sommer, Robert S. A1 - Kalbe, Johannes A1 - Ekstrom, Jonas A1 - Benecke, Norbert A1 - Liljegren, Ronnie T1 - Range dynamics of the reindeer in Europe during the last 25,000 years JF - Journal of biogeography N2 - Aim To understand the role and significance of the reindeer, Rangifer tarandus (Linnaeus, 1758), as a specific indicator in terms of late Quaternary biogeography and to determine the effects of global climate change on its range and local extinction dynamics at the end of the Ice Age. Location Late Pleistocene/early Holocene range of reindeer over all of central and western Europe, including southern Scandinavia and northern Iberia, but excluding Russia, Belarus and the Ukraine. Methods Radiocarbon-dated subfossil records of R. tarandus from both archaeological and natural deposits younger than 25,000 years were assembled in a database. The distribution area was divided into six representative regions. The C-14 dates were calibrated and plotted chronologically in maps in order to compare presence and absence and regional extinction patterns from one region to another. Main conclusions The late Quaternary record for reindeer in Europe during the last 25 kyr shows a climate-driven dispersal and retreat in response to climate change, with regional variations. The collapse of the mammoth steppe biome did not lead to the local extinction in Europe, as in the case of other megafaunal species. Rangifer tarandus co-existed for about 3000 years during the Late Glacial and early Holocene with typical temperate species such as red deer and roe deer in non-analogue faunal communities. The regional extinction at the end of the Pleistocene coincides with the transition from light open birch/pine forests to pine/deciduous forests. KW - Climate change KW - environmental change KW - extinction KW - global change KW - late Quaternary KW - Pleistocene/Holocene transition KW - Rangifer tarandus KW - reindeer Y1 - 2014 U6 - https://doi.org/10.1111/jbi.12193 SN - 0305-0270 SN - 1365-2699 VL - 41 IS - 2 SP - 298 EP - 306 PB - Wiley-Blackwell CY - Hoboken ER - TY - INPR A1 - Mischke, Steffen A1 - Chen, Fahu T1 - Introduction to "Late Pleistocene and Holocene climate change in continental Asia" T2 - Journal of paleolimnolog Y1 - 2014 U6 - https://doi.org/10.1007/s10933-013-9750-6 SN - 0921-2728 SN - 1573-0417 VL - 51 IS - 2 SP - 157 EP - 159 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Gianniotis, Nikolaos A1 - Kuehn, Nicolas A1 - Scherbaum, Frank T1 - Manifold aligned ground motion prediction equations for regional datasets JF - Computers & geosciences : an international journal devoted to the publication of papers on all aspects of geocomputation and to the distribution of computer programs and test data sets ; an official journal of the International Association for Mathematical Geology N2 - Inferring a ground-motion prediction equation (GMPE) for a region in which only a small number of seismic events has been observed is a challenging task. A response to this data scarcity is to utilise data from other regions in the hope that there exist common patterns in the generation of ground motion that can contribute to the development of a GMPE for the region in question. This is not an unreasonable course of action since we expect regional GMPEs to be related to each other. In this work we model this relatedness by assuming that the regional GMPEs occupy a common low-dimensional manifold in the space of all possible GMPEs. As a consequence, the GMPEs are fitted in a joint manner and not independent of each other, borrowing predictive strength from each other's regional datasets. Experimentation on a real dataset shows that the manifold assumption displays better predictive performance over fitting regional GMPEs independent of each other. (C) 2014 Elsevier Ltd. All rights reserved. KW - Ground-motion-model KW - Bagging KW - Ensembles KW - Manifold KW - Regional-dependence Y1 - 2014 U6 - https://doi.org/10.1016/j.cageo.2014.04.014 SN - 0098-3004 SN - 1873-7803 VL - 69 SP - 72 EP - 77 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Taft, Linda A1 - Mischke, Steffen A1 - Wiechert, Uwe A1 - Leipe, Christian A1 - Rajabov, Ilhomjon A1 - Riedel, Frank T1 - Sclerochronological oxygen and carbon isotope ratios in Radix (Gastropoda) shells indicate changes of glacial meltwater flux and temperature since 4,200 cal yr BP at Lake Karakul, eastern Pamirs (Tajikistan) JF - Journal of paleolimnolog N2 - We report delta O-18 and delta C-13 values of 21 fossil shells from the aquatic gastropod Radix from a sediment core taken in the eastern basin of Lake Karakul, Tajikistan (38.86-39.16A degrees N, 73.26-73.56A degrees E, 3,928 m above sea level) and covering the last 4,200 cal yr BP. The lake is surrounded by many palaeoshorelines evidencing former lake-level changes, most likely triggered by changes in meltwater flux. This hypothesis was tested by interpreting the isotope ratios of Radix shells together with delta O-18 values of Ostracoda and of authigenic aragonite. The mean delta O-18 values of Radix and Ostracoda fall along the same long-term trend indicating a change in the isotopic composition of precipitation, which contributed to the glaciers in the catchment as snow and finally as melt water to the lake. The sclerochronological delta O-18 and delta C-13 patterns in Radix shells provide seasonal weather information, which is discussed in context with previously proposed climatic changes during the last 4,200 cal yr BP. The period between similar to 4,200 and 3,000 cal yr BP was characterized by stepwise glacier advance in the catchment most likely due to a precipitation surplus. Subsequently the climate remained relatively cold but the lake level fluctuated, as indicated by ostracod shell isotope data. From similar to 1,800 cal yr BP the sclerochronological patterns provide evidence for increasing melt water flux and transport of allochthonous carbon into the lake, most likely due to an accelerated glacier retreat. The period around 1,500 cal yr BP was characterized by strong warming, increasing meltwater flux, glacier retreat and an increasing lake level. Warm conditions continued until similar to 500 cal yr I'P probably representing the end of the Medieval Warm Period. A short relatively cold (dry?) period and a lower lake level are assumed for similar to 350 cal yr BP, possibly an analogue to the Maunder Minimum cooling in the North Atlantic region. Our results show that the lake system is complex, and that changes were triggered by external forcing and feedbacks. The similarity of delta O-18 values in Radix and ostracod shells demonstrates that both archives provide complementary information. KW - Palaeolimnology KW - Stable isotopes KW - Gastropods KW - Sclerochronology KW - Late Holocene KW - Central Asia Y1 - 2014 U6 - https://doi.org/10.1007/s10933-014-9776-4 SN - 0921-2728 SN - 1573-0417 VL - 52 IS - 1-2 SP - 27 EP - 41 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Rieckh, Helene A1 - Gerke, Horst H. A1 - Siemens, Jan A1 - Sommer, Michael T1 - Water and dissolved carbon fluxes in an eroding soil landscape depending on terrain position JF - Vadose zone journal N2 - Leaching of dissolved C in arable hummocky ground moraine soil landscapes is characterized by a spatial continuum of more or less erosion-affected Luvisols, Calcaric Regosols at exposed positions, and Colluvic Regosols in depressions. Our objective was to estimate the fluxes of dissolved C in four differently eroded soils as affected by erosion-induced pedological and soil structural alterations. In this model study, we considered landscape position effects by adapting the water table as the bottom boundary condition and erosion effects by using pedon-specific soil hydraulic properties. The one-dimensional vertical water movement was described with the Richards equation using HYDRUS-1D. Solute fluxes were obtained by combining calculated water fluxes with concentrations of dissolved organic and inorganic C (DOC and DIC, respectively) measured from soil solution extracted by suction cups at biweekly intervals. In the 3-yr period (2010-2012), DOC fluxes in the 2-m soil depth were similar at the three non-colluvic locations with -0.8 +/- 0.1 g m(-2) yr(-1) (i.e., outflow) but were 0.4 g m(-2) yr(-1) (i.e., input) in the depression. The DIC fluxes ranged from -10.2 g m(-2) yr(-1) for the eroded Luvisol, -9.2 g m(-2) yr(-1) for the Luvisol, and -6.1 g m(-2) yr(-1) for the Calcaric Regosol to 3.2 g m(-2) yr(-1) for the Colluvic Regosol. The temporal variations in DOC and DIC fluxes were controlled by water fluxes. The spatially distributed leaching results corroborate the hypothesis that the effects of soil erosion influence fluxes through modified hydraulic and transport properties and terrain-dependent boundary conditions. Y1 - 2014 U6 - https://doi.org/10.2136/vzj2013.10.0173 SN - 1539-1663 VL - 13 IS - 7 PB - Soil Science Society of America CY - Madison ER - TY - JOUR A1 - Koenig, H. J. A1 - Zhen, L. A1 - Helming, K. A1 - Uthes, S. A1 - Yang, L. A1 - Cao, Xianyong A1 - Wiggering, Hubert T1 - Assessing the impact of the sloping land conversion programme on rural sustainability in Guyuan, Western China JF - Land degradation & development N2 - The goal of China's sloping land conversion programme (SLCP) is to combat soil erosion and to reduce rural poverty. An ex-ante assessment of possible SLCP impacts was conducted with a focus on rural sustainability, taking the drought-prone region of Guyuan in Western China as an example. The Framework for Participatory Impact Assessment (FoPIA) was used to conduct two complementary impact assessments, one assessing SLCP impacts at regional level and a second one assessing alternative forest management options, to explore possible trade-offs among the economic, social and environmental dimensions of sustainability. Regional stakeholders assessed the SLCP to be capable of reducing soil erosion but felt it negatively affected rural employment, and a further continuation of the Programme was advocated. Assessment of three forest management scenarios by scientists showed that an orientation towards energy forests is potentially beneficial to all three sustainability dimensions. Ecological forests had disproportionate positive impacts on environmental functions and adverse impact on the other two sustainability dimensions. Economic forests were assessed to serve primarily the economic and social sustainability dimensions, while environmental impacts were still tolerable. The FoPIA results were evaluated against the available literature on the SLCP. Overall, the assessment results appeared to be reasonable, but the results of the regional stakeholders appeared to be too optimistic compared with the more critical assessment of the scientists. The SLCP seems to have the potential to tackle soil erosion but requires integrated forest management to minimize the risk of water stress while contributing to economic and social benefits in Guyuan. Copyright (C) 2012 John Wiley & Sons, Ltd. KW - land conversion KW - land use KW - afforestation KW - land use functions KW - Grain for Green Project KW - ex-ante impact assessment KW - sustainable development KW - stakeholder participation Y1 - 2014 U6 - https://doi.org/10.1002/ldr.2164 SN - 1085-3278 SN - 1099-145X VL - 25 IS - 4 SP - 385 EP - 396 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Pro, C. A1 - Buforn, Elisa A1 - Cesca, Simone A1 - Sanz de Galdeano, C. A1 - Udias, A. T1 - Rupture process of the Lorca (southeast Spain) 11 May 2011 (M (w)=5.1) earthquake JF - Journal of seismology N2 - On 11 May 2011, a M (w) = 5.1 earthquake shook the town of Lorca (SE Spain) causing a disproportionately large damage for its magnitude. In order to contribute to knowledge of the behavior of the active faults present in the region and define the parameters which control their motion, we made a detailed study of the rupture process of this earthquake from inversion of body waves at regional and teleseismic distances. Ground motion displacements obtained in this way are in agreement with near-field strong motion data and GPS observations recorded in Lorca. We have obtained a partly bilateral rupture propagating to WSW (238A degrees, 54A degrees, 59A degrees) with 27 cm of maximum slip and shallow focus (4 km). The fault plane orientation corresponds to that of the Cejo de los Enamorados Fault located NE of the Lorca town and parallel to the Alhama de Murcia Fault. The distribution of slip on the fault plane can explain the lack of any observed surface rupture as we found that the rupture started at 4-km depth along a plane dipping at 54A degrees, with motion propagating upward to stop at 1.5 km below the surface. The strong motion and GPS data recorded near the epicenter are in agreement with the maximum slip on the fault. Directivity effects and the extreme shallowness of the rupture could explain the considerable damage that the earthquake caused in the town of Lorca. KW - Seismic slip distribution KW - Directivity KW - Ground motion and GPS Y1 - 2014 U6 - https://doi.org/10.1007/s10950-014-9421-8 SN - 1383-4649 SN - 1573-157X VL - 18 IS - 3 SP - 481 EP - 495 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Walz, Ariane A1 - Braendle, J. M. A1 - Lang, D. J. A1 - Brand, Fridolin Simon A1 - Briner, Simon A1 - Elkin, C. A1 - Hirschi, C. A1 - Huber, R. A1 - Lischke, H. A1 - Schmatz, D. R. T1 - Experience from downscaling IPCC-SRES scenarios to specific national-level focus scenarios for ecosystem service management JF - Technological forecasting & social change N2 - Scenario analysis is a widely used approach to incorporate uncertainties in global change research. In the context of regional ecosystem service and landscape management where global IPCC climate simulations and their downscaled derivates are applied, it can be useful to work with regional sodo-economic scenarios that are coherent with the global IPCC scenarios. The consistency with the original source scenarios, transparency and reproducibility of the methods used as well as the internal consistency of the derived scenarios are important methodological prerequisites for coherently downscaling pre-existing source scenarios. In contrast to well-established systematic-qualitative scenario techniques, we employ here a formal technique of scenario construction which combines expert judgement with a quantitative, indicator-based selection algorithm in order to deduce a formally consistent set of focus scenario. In our case study, these focus scenarios reflect the potential development pathways of major national-level drivers for ecosystem service management in Swiss mountain regions. The integration of an extra impact factor ("Global Trends") directly referring to the four principle SRES scenario families, helped us to formally internalise base assumptions of IPCC SRES scenarios to regional scenarios that address a different thematic focus (ecosystem service management), spatial level (national) and time horizon (2050). Compared to the well-established systematic-qualitative approach, we find strong similarities between the two methods, including the susceptibility to personal judgement which is only partly reduced by the formal method. However, the formalised scenario approach conveys four clear advantages, (1) the better documentation of the process, (2) its reproducibility, (3) the openness in terms of the number and directions of the finally selected set of scenarios, and (4) its analytical power. (C) 2013 Elsevier Inc. All rights reserved. KW - Nested scenarios KW - Formalised scenario analysis KW - Regional ecosystem service management KW - Downscaling socio-economic scenarios KW - IPCC Y1 - 2014 U6 - https://doi.org/10.1016/j.techfore.2013.08.014 SN - 0040-1625 SN - 1873-5509 VL - 86 SP - 21 EP - 32 PB - Elsevier CY - New York ER - TY - JOUR A1 - Trauth, Martin H. T1 - A new probabilistic technique to build an age model for complex stratigraphic sequences JF - Quaternary geochronology : the international research and review journal on advances in quaternary dating techniques N2 - The age models of fluvio-lacustrine sedimentary sequences are often subject of discussions in paleoclimate research. The techniques employed to build an age model are very diverse, ranging from visual or intuitive estimation of the age-depth relationship over linear or spline interpolations between age control points to sophisticated Bayesian techniques also taking into account the most likely deposition times of the type of sediment within the sequence. All these methods, however, fail in detecting abrupt variations in sedimentation rates, including the possibility of episodes of no deposition (hiatus), which is the strength of the method presented in this work. The new technique simply compares the deposition time of equally thick sediment slices from the differences of subsequent radiometric age dates and the unit deposition times of the various sediment types. The percentage overlap of the distributions of these two sources of information, together with the evidence from the sedimentary record, helps to build an age model of complex sequences including abrupt variations in the rate of deposition including one or many hiatuses. (C) 2014 Elsevier B.V. All rights reserved. KW - Age-depth modelling KW - Stratigraphy KW - Sedimentation rate KW - Hiatus KW - MATLAB Y1 - 2014 U6 - https://doi.org/10.1016/j.quageo.2014.03.001 SN - 1871-1014 SN - 1878-0350 VL - 22 SP - 65 EP - 71 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - van Schaik, Loes A1 - Palm, Juliane A1 - Klaus, Julian A1 - Zehe, Erwin A1 - Schroeder, Boris T1 - Linking spatial earthworm distribution to macropore numbers and hydrological effectiveness JF - Ecohydrology : ecosystems, land and water process interactions, ecohydrogeomorphology N2 - Due to its high spatial and temporal variability, preferential flow is difficult to measure and quantify. Earthworms create macropores that provide common pathways for preferential flow. Therefore in this article, we link earthworm abundance to macropore numbers and hydrological effectiveness, with the future aim to use species distribution models of earthworms for the spatial parameterization of preferential flow. Earthworms are generally categorized into three ecological types with varying burrowing behaviour, resulting in a different impact on soil hydrological processes. Therefore, we studied the relationships between the abundance of the earthworm ecological types and macropores of different size classes and in different soil depths. The abundance and biomass of earthworms were well correlated to different sizes of macropores in different soil depths. This is mainly the case for the larger, vertically oriented macropores (>6mm diameter), which are generally connected to the soil surface and hydrologically most effective. The correlation of total earthworm biomass and macropores ranges from 072 to 089 for different soil depths. Although there is quite some variation in infiltration patterns, infiltration from macropores into the matrix is profile-specific, as it varies strongly between profiles, but not within one profile. Macropore coating seems to have a larger effect on this macropore matrix interaction than the soil physical properties of the matrix. Although the amount of macropores and their effectiveness are clearly related to the earthworm distribution, the variation in infiltration from macropores to soil matrix should be further studied. KW - macropores KW - spatial parameterization KW - earthworm ecological types KW - infiltration patterns KW - preferential flow Y1 - 2014 U6 - https://doi.org/10.1002/eco.1358 SN - 1936-0584 SN - 1936-0592 VL - 7 IS - 2 SP - 401 EP - 408 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Prasad, Sushma A1 - Anoop, A. A1 - Riedel, N. A1 - Sarkar, Saswati A1 - Menzel, P. A1 - Basavaiah, Nathani A1 - Krishnan, R. A1 - Fuller, D. A1 - Plessen, Birgit A1 - Gaye, B. A1 - Roehl, U. A1 - Wilkes, H. A1 - Sachse, Dirk A1 - Sawant, R. A1 - Wiesner, M. G. A1 - Stebich, M. T1 - Prolonged monsoon droughts and links to Indo-Pacific warm pool: A Holocene record from Lonar Lake, central India JF - Earth & planetary science letters N2 - Concerns about the regional impact of global climate change in a warming scenario have highlighted the gaps in our understanding of the Indian Summer Monsoon (ISM, also referred to as the Indian Ocean summer monsoon) and the absence of long term palaeoclimate data from the central Indian core monsoon zone (CMZ). Here we present the first high resolution, well-dated, multiproxy reconstruction of Holocene palaeoclimate from a 10 m long sediment core raised from the Lonar Lake in central India. We show that while the early Holocene onset of-intensified monsoon in the CMZ is similar to that reported from other ISM records, the Lonar data shows two prolonged droughts (PD, multidecadal to centennial periods of weaker monsoon) between 4.6-3.9 and 2-0.6 cal ka. A comparison of our record with available data from other ISM influenced sites shows that the impact of these PD was observed in varying degrees throughout the ISM realm and coincides with intervals of higher solar irradiance. We demonstrate that (i) the regional warming in the Indo-Pacific Warm Pool (IPWP) plays an important role in causing ISM PD through changes in meridional overturning circulation and position of the anomalous Walker cell; (ii) the long term influence of conditions like El Nino-Southern Oscillation (ENSO) on the ISM began only ca. 2 cal ka BP and is coincident with the warming of the southern IPWP; (iii) the first settlements in central India coincided with the onset of the first PD and agricultural populations flourished between the two PD, highlighting the significance of natural climate variability and PD as major environmental factors affecting human settlements. KW - Indian summer monsoon KW - ENSO KW - prolonged droughts KW - Holocene KW - Lonar Lake Y1 - 2014 U6 - https://doi.org/10.1016/j.epsl.2014.01.043 SN - 0012-821X SN - 1385-013X VL - 391 SP - 171 EP - 182 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Hayes, Christopher T. A1 - Anderson, Robert F. A1 - Fleisher, Martin Q. A1 - Serno, Sascha A1 - Winckler, Gisela A1 - Gersonde, Rainer T1 - Biogeography in Pa-231/Th-230 ratios and a balanced Pa-231 budget for the Pacific Ocean JF - Earth & planetary science letters N2 - The ratio of unsupported protactinium-231 to thorium-230 in marine sediments, (Pa/Th)(xs), is potentially sensitive to several processes of oceanographic and climatological interest: deep ocean circulation, marine biological productivity (as it relates to total particle flux) and particle composition (specifically, biogenic opal and authigenic Mn). In order to attribute variations in (Pa/Th)(xs) observed in sediment records to changes in specific processes through time, a better understanding of the chemical cycling of these elements in the modern ocean is necessary. To this end, a survey was undertaken of (Pa/Th)(xs) in surface sediments from the subarctic Pacific (SO202-INOPEX expedition) in combination with a Pacific-wide compilation of published data. Throughout the Pacific, (Pa/Th)(xs) is robustly correlated with the opal content of sediments. In the North and equatorial Pacific, simultaneous positive correlations with productivity indicators suggest that boundary scavenging and opal scavenging combine to enhance the removal of Pa in the eastern equatorial Pacific and subarctic Pacific. Deep ocean water mass ageing (>3.5 km) associated with the Pacific overturning appears to play a secondary role in determining the basin scale distribution of (Pa/Th)(xs). A basin-wide extrapolation of Pa removal is performed which suggests that the Pacific Pa budget is nearly in balance. We hypothesize that through time (Pa/Th)(xs) distributions in the Pacific could define the evolving boundaries of contrasting biogeographic provinces in the North Pacific, while the influence of hydrothermal scavenging of Pa potentially confounds this approach in the South Pacific. KW - thorium KW - protactinium KW - biogeographic provinces KW - boundary scavenging KW - INOPEX Y1 - 2014 U6 - https://doi.org/10.1016/j.epsl.2014.02.001 SN - 0012-821X SN - 1385-013X VL - 391 SP - 307 EP - 318 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Schibalski, Anett A1 - Lehtonen, Aleksi A1 - Schroeder, Boris T1 - Climate change shifts environmental space and limits transferability of treeline models JF - Ecography : pattern and diversity in ecology ; research papers forum N2 - Our study aims at gaining insights into the processes determining the current treeline dynamics in Finnish Lapland. Using forest surveys conducted in 1978 and 2003 we modelled the occurrence and abundance of three dominant tree species in Finnish Lapland, i.e. Pinus sylvestris, Picea abies and Betula pubescens, with boosted regression trees. We assessed the importance of climatic, biotic and topographic variables in predicting tree occurrence and abundance based on their relative importance and response curves. We compared temporal and spatial transferability by using an extended transferability index. Site fertility, the abundance of co-occurring species and growing degree days were generally the most important predictors for both occurrence and abundance across all species and datasets. Climatic predictors were more important for modelling occurrences than for modelling abundances. Occurrence models were able to reproduce the observed treeline pattern within one time period or region. Abundance models underestimated basal area but captured the general pattern of low and high values. Model performance as well as transferability differed considerably between species and datasets. Pinus sylvestris was modelled more successfully than P. abies and B. pubescens. Generally, spatial transferability was greater than temporal transferability. Comparing the environmental space between datasets revealed that transferring models means extrapolating to novel environments, providing a plausible explanation for limited transferability. Our study illustrates how climate change can shift the environmental space and lead to limited model transferability. We identified non-climatic factors to be important in predicting the distribution of dominant tree species, contesting the widespread assumption of climatically induced range expansion. Y1 - 2014 U6 - https://doi.org/10.1111/j.1600-0587.2013.00368.x SN - 0906-7590 SN - 1600-0587 VL - 37 IS - 4 SP - 321 EP - 335 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Tu, Rui T1 - Fast determination of displacement by PPP velocity estimation JF - Geophysical journal international N2 - Global Positioning System (GPS) has been proven to be an effective tool to retrieve high-precision displacement for the natural hazard monitoring. The network positioning and Precise Point Positioning (PPP) are the two basic approaches for its data solution, but the former one can only get a relative displacement within the local reference frame and requires a complex and continuously linked infrastructure, and the latter one with a long convergence time to obtain the absolute displacements within the global reference frame. To overcome these drawbacks, this paper proposed a method of fast determining the displacement by PPP velocity estimation (PPPVE). The key of the approach is that the velocity vector parameters are not correlated with other unknown parameters, such as ambiguities and atmosphere, so they can be fast and accurately estimated and integrated into displacements. The validation shows that the displacement can be provided with a precision of 1-2 cm in 1 min by PPPVE. In additional, the Kalman smoothing estimation can be used to improve the PPP solution. KW - Satellite geodesy KW - Space geodetic surveys KW - Earthquake ground motions Y1 - 2014 U6 - https://doi.org/10.1093/gji/ggt480 SN - 0956-540X SN - 1365-246X VL - 196 IS - 3 SP - 1397 EP - 1401 PB - Oxford Univ. Press CY - Oxford ER - TY - INPR A1 - Scheffler, Franziska A1 - Oberhänsli, Roland A1 - Pourteau, Amaury A1 - Candan, Osman A1 - Di Lucia, Matteo T1 - The rosetta marbles from feslegen, A-ren unit, SW Anatolia T2 - International journal of earth sciences Y1 - 2014 U6 - https://doi.org/10.1007/s00531-013-0936-y SN - 1437-3254 SN - 1437-3262 VL - 103 IS - 2 SP - 485 EP - 486 PB - Springer CY - New York ER - TY - JOUR A1 - Riggelsen, Carsten A1 - Ohrnberger, Matthias T1 - A machine learning approach for improving the detection capabilities at 3C Seismic Stations JF - Pure and applied geophysics N2 - We apply and evaluate a recent machine learning method for the automatic classification of seismic waveforms. The method relies on Dynamic Bayesian Networks (DBN) and supervised learning to improve the detection capabilities at 3C seismic stations. A time-frequency decomposition provides the basis for the required signal characteristics we need in order to derive the features defining typical "signal" and "noise" patterns. Each pattern class is modeled by a DBN, specifying the interrelationships of the derived features in the time-frequency plane. Subsequently, the models are trained using previously labeled segments of seismic data. The DBN models can now be compared against in order to determine the likelihood of new incoming seismic waveform segments to be either signal or noise. As the noise characteristics of seismic stations varies smoothly in time (seasonal variation as well as anthropogenic influence), we accommodate in our approach for a continuous adaptation of the DBN model that is associated with the noise class. Given the difficulty for obtaining a golden standard for real data (ground truth) the proof of concept and evaluation is shown by conducting experiments based on 3C seismic data from the International Monitoring Stations, BOSA and LPAZ. Y1 - 2014 U6 - https://doi.org/10.1007/s00024-012-0592-3 SN - 0033-4553 SN - 1420-9136 VL - 171 IS - 3-5 SP - 395 EP - 411 PB - Springer CY - Basel ER - TY - JOUR A1 - Messmer, Tobias A1 - Elsenbeer, Helmut A1 - Wilcke, Wolfgang T1 - High exchangeable calcium concentrations in soils on Barro Colorado Island, Panama JF - Geoderma : an international journal of soil science N2 - The soils on four lithologies (basaltic conglomerates, Bohio; Andesite; volcanoclastic sediments with basaltic agglomerates, Caimito volcanic; foraminiferal limestone, Caimito marine) on Barro Colorado Island (BCI have high exchangeable Ca concentrations and cation-exchange capacities (CEC) compared to other tropical soils on similar parent material. In the 0-10 cm layer of 24 mineral soils, pH values ranged from 5.7 (Caimito volcanic and Andesite) to 6.5 (Caimito marine), concentrations of exchangeable Ca from 134 mmol(c) kg(-1) (Caimito volcanic) to 585 mmolc kg-1 (Caimito marine), and cation exchange capacities from 317 mmol(c) kg(-1) (Caimito volcanic) to 933 mmol(c) kg(-1) (Caimito marine). X-ray diffractometry of the fraction <2 mu m revealed that smectites dominated the clay mineral assemblage in soil except on Caimito volcanic, where kaolinite was the dominant clay mineral. Exchangeable Ca concentrations decreased with increasing soil depth except on Caimito marine. The weathering indices Chemical Index of Alteration (CIA), Plagioclase Index of Alteration (PIA) and Weathering Index of Parker (WIP) determined for five soils on all geological formations, suggested that in contrast to expectation the topsoil (0-10 cm) appeared to be the least and the subsoil (50-70 cm) and saprolite (isomorphically weathered rock in the soil matrix) the most weathered. Additionally, the weathering indices indicated depletion of base cations and enrichment of Al-(hydr)oxides throughout the soil profile. Tree species did not have an effect on soil properties. Impeded leaching and the related occurrence of overland flow seem to be important in determining clay mineralogy. Our results suggest that (i) edaphic conditions favor the formation of smectites on most lithologies resulting in high CEC and thus high retention capacity for Ca and (ii) that there is an external source such as dust or sea spray deposition supplying Ca to the soils. KW - Panama KW - Cation-exchange capacity KW - Exchangeable Ca KW - Clay mineralogy KW - Weathering indices Y1 - 2014 U6 - https://doi.org/10.1016/j.geoderma.2013.10.021 SN - 0016-7061 SN - 1872-6259 VL - 217 SP - 212 EP - 224 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Zimmermann, Alexander A1 - Zimmermann, Beate T1 - Requirements for throughfall monitoring: The roles of temporal scale and canopy complexity JF - Agricultural and forest meteorology N2 - A wide range of basic and applied problems in water resources research requires high-quality estimates of the spatial mean of throughfall. Many throughfall sampling schemes, however, are not optimally adapted to the system under study. The application of inappropriate sampling schemes may partly reflect the lack of generally applicable guidelines on throughfall sampling strategies. In this study we conducted virtual sampling experiments using simulated fields which are based on empirical throughfall data from three structurally distinct forests (a 12-year old teak plantation, a 5-year old young secondary forest, and a 130-year old secondary forest). In the virtual sampling experiments we assessed the relative error of mean throughfall estimates for 38 different throughfall sampling schemes comprising a variety of funnel- and trough-type collectors and a large range of sample sizes. Moreover, we tested the performance of each scheme for both event-based and accumulated throughfall data. The key findings of our study are threefold. First, as errors of mean throughfall estimates vary as a function of throughfall depth, the decision on which temporal scale (i.e. event-based versus accumulated data) to sample strongly influences the required sampling effort. Second, given a chosen temporal scale throughfall estimates can vary considerably as a function of canopy complexity. Accordingly, throughfall sampling in simply structured forests requires a comparatively modest effort, whereas heterogeneous forests can be extreme in terms of sampling requirements, particularly if the focus is on reliable data of small events. Third, the efficiency of trough-type collectors depends on the spatial structure of throughfall. Strong, long-ranging throughfall patterns decrease the efficiency of troughs substantially. Based on the results of our virtual sampling experiments, which we evaluated by applying two contrasting sampling approaches simultaneously, we derive readily applicable guidelines for throughfall monitoring. (C) 2014 Elsevier B.V. All rights reserved. KW - Throughfall KW - Interception KW - Uncertainty KW - Spatial structure KW - Sampling strategy KW - Forest ecosystem Y1 - 2014 U6 - https://doi.org/10.1016/j.agrformet.2014.01.014 SN - 0168-1923 SN - 1873-2240 VL - 189 SP - 125 EP - 139 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Wiggering, Hubert T1 - The geology - land use - nexus JF - Environmental earth sciences KW - Multifunctionality KW - Site-adequate land use KW - Ecosystem services KW - Land use conception Y1 - 2014 U6 - https://doi.org/10.1007/s12665-013-2908-8 SN - 1866-6280 SN - 1866-6299 VL - 71 IS - 12 SP - 5037 EP - 5044 PB - Springer CY - New York ER - TY - JOUR A1 - Xu, QingHai A1 - Cao, Xianyong A1 - Tian, Fang A1 - Zhang, ShengRui A1 - Li, YueCong A1 - Li, ManYue A1 - Li, Jie A1 - Liu, YaoLiang A1 - Liang, Jian T1 - Relative pollen productivities of typical steppe species in northern China and their potential in past vegetation reconstruction JF - Science China N2 - The Relative Pollen Productivities (RPPs) of common steppe species are estimated using Extended R-value (ERV) model based on pollen analysis and vegetation survey of 30 surface soil samples from typical steppe area of northern China. Artemisia, Chenopodiaceae, Poaceae, Cyperaceae, and Asteraceae are the dominant pollen types in pollen assemblages, reflecting the typical steppe communities well. The five dominant pollen types and six common types (Thalictrum, Iridaceae, Potentilla, Ephedra, Brassicaceae, and Ulmus) have strong wind transport abilities; the estimated Relevant Source Area of Pollen (RSAP) is ca. 1000 m when the sediment basin radius is set at 0.5 m. Ulmus, Artemisia, Brassicaceae, Chenopodiaceae, and Thalictrum have relative high RPPs; Poaceae, Cyperaceae, Potentilla, and Ephedra pollen have moderate RPPs; Asteraceae and Iridaceae have low RPPs. The reliability test of RPPs revealed that most of the RPPs are reliable in past vegetation reconstruction. However, the RPPs of Asteraceae and Iridaceae are obviously underestimated, and those of Poaceae, Chenopodiaceae, and Ephedra are either slightly underestimated or slightly overestimated, suggesting that those RPPs should be considered with caution. These RPPs were applied to estimating plant abundances for two fossil pollen spectra (from the Lake Bayanchagan and Lake Haoluku) covering the Holocene in typical steppe area, using the "Regional Estimates of Vegetation Abundance from Large Sites" (REVEALS) model. The RPPs-based vegetation reconstruction revealed that meadow-steppe dominated by Poaceae, Cyperaceae, and Artemisia plants flourished in this area before 6500-5600 cal yr BP, and then was replaced by present typical steppe. KW - typical steppe KW - modern surface pollen KW - relative pollen productivity KW - relevant pollen source area KW - paleovegetation Y1 - 2014 U6 - https://doi.org/10.1007/s11430-013-4738-7 SN - 1674-7313 SN - 1869-1897 VL - 57 IS - 6 SP - 1254 EP - 1266 PB - Science China Press CY - Beijing ER - TY - JOUR A1 - Ghassemi, Mohammad R. A1 - Fattahi, Morteza A1 - Landgraf, Angela A1 - Ahmadi, Mehdi A1 - Ballato, Paolo A1 - Tabatabaei, Saeid H. T1 - Kinematic links between the Eastern Mosha Fault and the North Tehran Fault, Alborz range, northern Iran JF - Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth N2 - Kinematic interaction of faults is an important issue for detailed seismic hazard assessments in seismically active regions. The Eastern Mosha Fault (EMF) and the North Tehran Fault (NTF) are two major active faults of the southern central Alborz mountains, located in proximity of Tehran (population similar to 9 million). We used field, geomorphological and paleoseismological data to explore the kinematic transition between the faults, and compare their short-term and long-term history of activity. We introduce the Niknamdeh segment of the NTF along which the strike-slip kinematics of EMF is transferred onto the NTF, and which is also responsible for the development of a pull-apart basin between the eastern segments of the NTF. The Ira trench site at the linkage zone between the two faults reveals the history of interaction between rock avalanches, active faulting and sag-pond development. The kinematic continuity between the EMF and NTF requires updating of seismic hazard models for the NTF, the most active fault adjacent to the Tehran Metropolis. Study of offsets of large-scale morphological features along the EMF, and comparison with estimated slip rates along the fault indicates that the EMF has started its left-lateral kinematics between 3.2 and 4.7 Ma. According to our paleoseismological data and the morphology of the nearby EMF and NTF, we suggest minimum and maximum values of about 1.8 and 3.0 mm/year for the left-lateral kinematics on the two faults in their linkage zone, averaged over Holocene time scales. Our study provides a partial interpretation, based on available data, for the fault activity in northeastern Tehran region, which may be completed with studies of other active faults of the region to evaluate a more realistic seismic hazard analysis for this heavily populated major city. (C) 2014 Elsevier B.V. All rights reserved. KW - Mosha Fault KW - North Tehran Fault KW - Alborz range KW - Slip rate KW - Fault linkage and interaction KW - Paleoseismology Y1 - 2014 U6 - https://doi.org/10.1016/j.tecto.2014.03.007 SN - 0040-1951 SN - 1879-3266 VL - 622 SP - 81 EP - 95 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Mischke, Steffen A1 - Almogi-Labin, Ahuva A1 - Al-Saqarat, Bety A1 - Rosenfeld, Arik A1 - Elyashiv, Hadar A1 - Boomer, Ian A1 - Stein, Mordechai A1 - Lev, Lilach A1 - Ito, Emi T1 - An expanded ostracod-based conductivity transfer function for climate reconstruction in the Levant JF - Quaternary science reviews : the international multidisciplinary research and review journal N2 - We present the first modern calibration dataset linking ostracod assemblage composition to water chemistry, and other site-specific variables, in the hydrologically and geopolitically sensitive southern Levant region. A total of 42 ostracod taxa were recorded from the 178 sampled sites in Israel and Jordan. Ilyocypris spp., Heterocypris salina and Cypridopsis vidua are the most abundant taxa. Species strictly confined to freshwater conditions are Prionocypris zenkeri, Gomphocythere ortali and Prionocypris olivaceus. In contrast, H. sauna, Bradleytriebella lineata and Cyprideis torosa show high frequencies in brackish waters (waters with higher conductivity). Humphcypris subterranea, G. ortali, P. olivaceus and Cypridopsis elongata apparently prefer flowing waters. Specific conductivity optima and tolerance ranges were calculated for the recorded ostracod species and may be used for the palaeoenvironmental assessment of fossil ostracod assemblages. In addition, a transfer-function for quantitative specific conductivity estimation based on 141 samples was established with weighted averaging partial least squares regression (WA-PLS). The resulting coefficient of determination r(2) between observed and predicted conductivity values (0.72) and the root-mean-square error of prediction (RMSEP) in % gradient length (13.1) indicate that conductivity may be reliably estimated from ostracod assemblage data. The transfer function was first applied to last glacial ostracod assemblage data from an archaeological trench in the Sea of Galilee (northern Israel). Relatively large conductivity fluctuations between ca 1 and 7 mS cm(-1) were inferred for the period 24-20 cal ka BP. In addition, four episodes of freshwater influx near the site of the trench were identified from the presence of shells of freshwater and stream-dwelling species intermingled with very abundant shells of Cyprideis torosa. The results of our study allow a better use of Quaternary ostracods from the Levant as palaeoenvironmental indicators of water-body types and past conductivity levels and will contribute to a better understanding of Quaternary environmental and climate change in the Levant. (C) 2014 Elsevier Ltd. All rights reserved. KW - Ostracoda KW - Transfer function KW - Conductivity KW - Salinity KW - Near East KW - Sea of Galilee KW - Ohalo Site Y1 - 2014 U6 - https://doi.org/10.1016/j.quascirev.2014.04.004 SN - 0277-3791 VL - 93 SP - 91 EP - 105 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Wang, Lifeng A1 - Hainzl, Sebastian A1 - Zöller, Gert T1 - Assessment of stress coupling among the inter-, co- and post-seismic phases related to the 2004 M6 Parkfield earthquake JF - Geophysical journal international N2 - Due to large uncertainties and non-uniqueness in fault slip inversion, the investigation of stress coupling based on the direct comparison of independent slip inversions, for example, between the coseismic slip distribution and the interseismic slip deficit, may lead to ambiguous conclusions. In this study, we therefore adopt the stress-constrained joint inversion in the Bayesian approach of Wang et al., and implement the physical hypothesis of stress coupling as a prior. We test the hypothesis that interseismic locking is coupled with the coseismic rupture, and the early post-seismic deformation is a stress relaxation process in response to the coseismic stress perturbation. We characterize the role of stress coupling in the seismic cycle by evaluating the efficiency of the model to explain the available data. Taking the 2004 M6 Parkfield earthquake as a study case, we find that the stress coupling hypothesis is in agreement with the data. The coseismic rupture zone is found to be strongly locked during the interseismic phase and the post-seismic slip zone is indicated to be weakly creeping. The post-seismic deformation plays an important role to rebuild stress in the coseismic rupture zone. Based on our results for the stress accumulation during both inter- and post-seismic phase in the coseismic rupture zone, together with the coseismic stress drop, we estimate a recurrence time of M6 earthquake in Parkfield around 23-41 yr, suggesting that the duration of 38 yr between the two recent M6 events in Parkfield is not a surprise. KW - Inverse theory KW - Seismic cycle KW - Dynamics and mechanics of faulting Y1 - 2014 U6 - https://doi.org/10.1093/gji/ggu102 SN - 0956-540X SN - 1365-246X VL - 197 IS - 3 SP - 1858 EP - 1868 PB - Oxford Univ. Press CY - Oxford ER -