TY - JOUR A1 - Zozulya, Dmitry R. A1 - Kullerud, Kare A1 - Ribacki, Enrico A1 - Altenberger, Uwe A1 - Sudo, Masafumi A1 - Savchenko, Yevgeny E. T1 - The newly discovered neoproterozoic aillikite occurrence in Vinoren (Southern Norway) BT - age, geodynamic position and mineralogical evidence of diamond-bearing mantle source JF - Minerals N2 - During the period 750-600 Ma ago, prior to the final break-up of the supercontinent Rodinia, the crust of both the North American Craton and Baltica was intruded by significant amounts of rift-related magmas originating from the mantle. In the Proterozoic crust of Southern Norway, the 580 Ma old Fen carbonatite-ultramafic complex is a representative of this type of rocks. In this paper, we report the occurrence of an ultramafic lamprophyre dyke which possibly is linked to the Fen complex, although Ar-40/Ar-39 data from phenocrystic phlogopite from the dyke gave an age of 686 +/- 9 Ma. The lamprophyre dyke was recently discovered in one of the Kongsberg silver mines at Vinoren, Norway. Whole rock geochemistry, geochronological and mineralogical data from the ultramafic lamprophyre dyke are presented aiming to elucidate its origin and possible geodynamic setting. From the whole-rock composition of the Vinoren dyke, the rock could be recognized as transitional between carbonatite and kimberlite-II (orangeite). From its diagnostic mineralogy, the rock is classified as aillikite. The compositions and xenocrystic nature of several of the major and accessory minerals from the Vinoren aillikite are characteristic for diamondiferous rocks (kimberlites/lamproites/UML): Phlogopite with kinoshitalite-rich rims, chromite-spinel-ulvospinel series, Mg- and Mn-rich ilmenites, rutile and lucasite-(Ce). We suggest that the aillikite melt formed during partial melting of a MARID (mica-amphibole-rutile-ilmenite-diopside)-like source under CO2 fluxing. The pre-rifting geodynamic setting of the Vinoren aillikite before the Rodinia supercontinent breakup suggests a relatively thick SCLM (Subcontinental Lithospheric Mantle) during this stage and might indicate a diamond-bearing source for the parental melt. This is in contrast to the about 100 Ma younger Fen complex, which were derived from a thin SCLM. KW - aillikite KW - phlogopite KW - carbonate KW - spinel KW - ilmenite KW - titanite KW - diamond KW - Vinoren KW - Southern Norway Y1 - 2020 U6 - https://doi.org/10.3390/min10111029 SN - 2075-163X VL - 10 IS - 11 PB - MDPI CY - Basel ER - TY - THES A1 - Zorn, Edgar Ulrich T1 - Monitoring lava dome growth and deformation with photogrammetric methods and modelling N2 - Lava domes are severely hazardous, mound-shaped extrusions of highly viscous lava and commonly erupt at many active stratovolcanoes around the world. Due to gradual growth and flank oversteepening, such lava domes regularly experience partial or full collapses, resulting in destructive and far-reaching pyroclastic density currents. They are also associated with cyclic explosive activity as the complex interplay of cooling, degassing, and solidification of dome lavas regularly causes gas pressurizations on the dome or the underlying volcano conduit. Lava dome extrusions can last from days to decades, further highlighting the need for accurate and reliable monitoring data. This thesis aims to improve our understanding of lava dome processes and to contribute to the monitoring and prediction of hazards posed by these domes. The recent rise and sophistication of photogrammetric techniques allows for the extraction of observational data in unprecedented detail and creates ideal tools for accomplishing this purpose. Here, I study natural lava dome extrusions as well as laboratory-based analogue models of lava dome extrusions and employ photogrammetric monitoring by Structure-from-Motion (SfM) and Particle-Image-Velocimetry (PIV) techniques. I primarily use aerial photography data obtained by helicopter, airplanes, Unoccupied Aircraft Systems (UAS) or ground-based timelapse cameras. Firstly, by combining a long time-series of overflight data at Volcán de Colima, México, with seismic and satellite radar data, I construct a detailed timeline of lava dome and crater evolution. Using numerical model, the impact of the extrusion on dome morphology and loading stress is further evaluated and an impact on the growth direction is identified, bearing important implications for the location of collapse hazards. Secondly, sequential overflight surveys at the Santiaguito lava dome, Guatemala, reveal surface motion data in high detail. I quantify the growth of the lava dome and the movement of a lava flow, showing complex motions that occur on different timescales and I provide insight into rock properties relevant for hazard assessment inferred purely by photogrammetric processing of remote sensing data. Lastly, I recreate artificial lava dome and spine growth using analogue modelling under controlled conditions, providing new insights into lava extrusion processes and structures as well as the conditions in which they form. These findings demonstrate the capabilities of photogrammetric data analyses to successfully monitor lava dome growth and evolution while highlighting the advantages of complementary modelling methods to explain the observed phenomena. The results presented herein further bear important new insights and implications for the hazards posed by lava domes. N2 - Lavadome sind kuppelförmige Aufstauungen aus zähflüssiger Lava und bilden sich häufig bei Eruptionen an aktiven Stratovulkanen. Sie stellen dabei oft eine erhebliche Gefahr für Menschen und Infrastruktur dar, weil Lavadome instabil werden können und bei einem Kollaps pyroklastische Ströme (auch Glutlawinen) erzeugen können. Diese können innerhalb von Minuten weite Flächen verwüsten, daher ist die Überwachung von Lavadomen und deren Wachstum mit genauen und zuverlässigen Daten von großer Bedeutung. In dieser Arbeit werden das Wachstum und die Bewegungen von Lavadomen mit fotogrammetrischen Methoden (Vermessungen anhand von Fotos) und mit Modellierungen in drei Teilstudien getestet und untersucht. Dazu wurden Daten sowohl an Lavadomen von Vulkanen in Mexiko und Guatemala als auch mittels künstlich erzeugter Dome im Labor erhoben. Hierbei wurden insbesondere das Structure-from-Motion-Verfahren, bei dem mithilfe einer Serie von Luftaufnahmen ein hochauflösendes 3D-Modell des Lavadoms und des Vulkans erstellt wird, und das Particle-Image-Velocimetry-Verfahren, bei dem aus einer Zeitreihe von Fotos kleinste Bewegungen detailliert gemessen werden können, verwendet. In der ersten Teilstudie wird aus einer Kombination von Überflugsbildern, Radardaten eines Satelliten, und seismischen Daten eine detaillierte Zeitreihe des Lavadom-Wachstums und der Kraterentwickelung am Volcán de Colima, Méxiko, erstellt. Anschließend werden die dabei erfassten Richtungen des Domwachstums mit numerischen Modellen auf Basis der fotogrammetrischen 3D-Modelle simuliert, welche zeigen, dass sich lokale Änderungen der Topografie auf die Wachstumsrichtung auswirken können. In der zweiten Teilstudie werden Drohnen in verschiedenen Zeitintervallen über einen Lavadom am Santa Maria Vulkan, Guatemala, geflogen. Die Überflugsdaten zeigen dabei Bewegungen sowohl an einem Lavastrom als auch ein Anschwellen des Doms mit jeweils unterschiedlichen Geschwindigkeiten. Ferner können die Daten genutzt werden um Oberflächentemperatur und die Viskosität (Zähflüssigkeit) der Lava zu vermessen, welche für die Gefahrenanalyse eine wichtige Rolle spielen. In der dritten Teilstudie werden künstliche Dom-Modelle mithilfe von Sand-Gips-Gemischen erzeugt. Diese können sowohl den Aufbau und Morphologie als auch die internen Strukturen von Lavadomen simulieren und anhand von Zeitraffer-Aufnahmen im Detail nachstellen. Die Ergebnisse zeigen, dass Fotogrammetrie und Modellierungen geeignete Mittel sind um Lavadome sowie deren Entstehungsprozesse und Gefahren zu verfolgen und neue Erkenntnisse zu gewinnen. T2 - Überwachung von Wachstum und Deformation an Lavadomen mit fotogrammetrischen Methoden und Modellierungen KW - Lava dome KW - Lavadom KW - Photogrammetry KW - Fotogrammetrie KW - Volcano KW - Vulkan KW - Analogue Model KW - Analogmodell Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-483600 ER - TY - JOUR A1 - Zimmermann, Heike Hildegard A1 - Stoof-Leichsenring, Kathleen Rosemarie A1 - Kruse, Stefan A1 - Müller, Juliane A1 - Stein, Ruediger A1 - Tiedemann, Ralf A1 - Herzschuh, Ulrike T1 - Changes in the composition of marine and sea-ice diatoms derived from sedimentary ancient DNA of the eastern Fram Strait over the past 30 000 years JF - Ocean science N2 - The Fram Strait is an area with a relatively low and irregular distribution of diatom microfossils in surface sediments, and thus microfossil records are scarce, rarely exceed the Holocene, and contain sparse information about past richness and taxonomic composition. These attributes make the Fram Strait an ideal study site to test the utility of sedimentary ancient DNA (sedaDNA) metabarcoding. Amplifying a short, partial rbcL marker from samples of sediment core MSM05/5-712-2 resulted in 95.7% of our sequences being assigned to diatoms across 18 different families, with 38.6% of them being resolved to species and 25.8% to genus level. Independent replicates show a high similarity of PCR products, especially in the oldest samples. Diatom sedaDNA richness is highest in the Late Weichselian and lowest in Mid- and Late Holocene samples. Taxonomic composition is dominated by cold-water and sea-ice-associated diatoms and suggests several reorganisations - after the Last Glacial Maximum, after the Younger Dryas, and after the Early and after the Mid-Holocene. Different sequences assigned to, amongst others, Chaetoceros socialis indicate the detectability of intra-specific diversity using sedaDNA. We detect no clear pattern between our diatom sedaDNA record and the previously published IP25 record of this core, although proportions of pennate diatoms increase with higher IP25 concentrations and proportions of Nitzschia cf. frigida exceeding 2% of the assemblage point towards past sea-ice presence. Y1 - 2020 U6 - https://doi.org/10.5194/os-16-1017-2020 SN - 1812-0784 VL - 16 IS - 5 SP - 1017 EP - 1032 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Ziemann, Martin Andreas A1 - Madariaga, Juan Manuel T1 - Applications of Raman spectroscopy in art and archaeology JF - Journal of Raman spectroscopy N2 - The 10th edition of the International Congress on the Application of Raman Spectroscopy in Art and Archaeology (RAA2019) was held in Potsdam (Germany) from 3 to 7 September 2019, with eight keynote lectures, 35 oral presentations and 18 Poster Presentations. The number of active participants was 68 delegates from 20 countries among the 236 authors that presented at least one work. Y1 - 2020 U6 - https://doi.org/10.1002/jrs.6054 SN - 0377-0486 SN - 1097-4555 VL - 52 IS - 1 SP - 8 EP - 14 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Ziebarth, Malte J. A1 - von Specht, Sebastian A1 - Heidbach, Oliver A1 - Cotton, Fabrice A1 - Anderson, John G. T1 - Applying conservation of energy to estimate earthquake frequencies from strain rates and stresses JF - Journal of geophysical research : Solid earth N2 - Estimating earthquake occurrence rates from the accumulation rate of seismic moment is an established tool of seismic hazard analysis. We propose an alternative, fault-agnostic approach based on the conservation of energy: the Energy-Conserving Seismicity Framework (ENCOS). Working in energy space has the advantage that the radiated energy is a better predictor of the damage potential of earthquake waves than the seismic moment release. In a region, ENCOS balances the stationary power available to cause earthquakes with the long-term seismic energy release represented by the energy-frequency distribution's first moment. Accumulation and release are connected through the average seismic efficiency, by which we mean the fraction of released energy that is converted into seismic waves. Besides measuring earthquakes in energy, ENCOS differs from moment balance essentially in that the energy accumulation rate depends on the total stress in addition to the strain rate tensor. To validate ENCOS, we exemplarily model the energy-frequency distribution around Southern California. We estimate the energy accumulation rate due to tectonic loading assuming poroelasticity and hydrostasis. Using data from the World Stress Map and assuming the frictional limit to estimate the stress tensor, we obtain a power of 0.8 GW. The uncertainty range, 0.3-2.0GW, originates mainly from the thickness of the seismogenic crust, the friction coefficient on preexisting faults, and models of Global Positioning System (GPS) derived strain rates. Based on a Gutenberg-Richter magnitude-frequency distribution, this power can be distributed over a range of energies consistent with historical earthquake rates and reasonable bounds on the seismic efficiency. Y1 - 2020 U6 - https://doi.org/10.1029/2020JB020186 SN - 2169-9313 SN - 2169-9356 VL - 125 IS - 8 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Zhu, Chuanbin A1 - Pilz, Marco A1 - Cotton, Fabrice T1 - Evaluation of a novel application of earthquake HVSR in site-specific amplification estimation JF - Soil dynamics and earthquake engineering N2 - Ground response analyses (GRA) model the vertical propagations of SH waves through flat-layered media (1DSH) and are widely carried out to evaluate local site effects in practice. Horizontal-to-vertical spectral ratio (HVSR) technique is a cost-effective approach to extract certain site-specific information, e.g., site fundamental frequency (f(0)), but HVSR values cannot be directly used to approximate the levels of S-wave amplifications. Motivated by the work of Kawase et al. (2019), we propose a procedure to correct earthquake HVSR amplitudes for direct amplification estimations. The empirical correction compensates HVSR by generic vertical amplification spectra categorized by the vertical fundamental frequency (f(0v)) via kappa-means clustering. In this investigation, we evaluate the effectiveness of the corrected HVSR in approximating observed linear amplifications in comparison with 1DSH modellings. We select a total of 90 KiK-net (Kiban Kyoshin network) surface-downhole sites which are found to have no velocity contrasts below their boreholes and thus of which surface-to-borehole spectral ratios (SBSRs) can be taken as their empirical transfer functions (ETFs). 1DSH-based theoretical transfer functions (TTFs) are computed in the linear domain considering uncertainties in Vs profiles through randomizations. Five goodness-of-fit metrics are adopted to gauge the closeness between observed (ETF) and predicted (i.e., TTF and corrected HVSR) amplifications in both amplitude and spectral shape over frequencies from f(0) to 25 Hz. We find that the empirical correction to HVSR is highly effective and achieves a "good match" in both spectral shape and amplitude at the majority of the 90 KiK-net sites, as opposed to less than one-third for the 1DSH modelling. In addition, the empirical correction does not require a velocity model, which GRAs require, and thus has great potentials in seismic hazard assessments. KW - site amplification KW - HVSR KW - ground response analysis KW - KiK-net KW - earthquake Y1 - 2020 U6 - https://doi.org/10.1016/j.soildyn.2020.106301 SN - 0267-7261 SN - 1879-341X VL - 139 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Zhu, Chuanbin A1 - Cotton, Fabrice A1 - Pilz, Marco T1 - Detecting site resonant frequency using HVSR BT - Fourier versus response spectrum and the first versus the highest peak frequency JF - Bulletin of the Seismological Society of America : BSSA N2 - In this investigation, we examine the uncertainties using the horizontal-to-vertical spectral ratio (HVSR) technique on earthquake recordings to detect site resonant frequencies at 207 KiK-net sites. Our results show that the scenario dependence of response (pseudospectral acceleration) spectral ratio could bias the estimates of resonant frequencies for sites having multiple significant peaks with comparable amplitudes. Thus, the Fourier amplitude spectrum (FAS) should be preferred in computing HVSR. For more than 80% of the investigated sites, the first peak (in the frequency domain) on the average HVSR curve over multiple sites coincides with the highest peak. However, for sites with multiple peaks, the highest peak frequency (f(p)) is less susceptible to the selection criteria of significant peaks and the extent of smoothing to spectrum than the first peak frequency (f(0)). Meanwhile, in comparison to the surface-to-borehole spectral ratio, f(0) tends to underestimate the predominant frequency (at which the largest amplification occurs) more than f(p). In addition, in terms of characterizing linear site response, f(p) shows a better overall performance than f(0). Based on these findings, we thus recommend that seismic network operators provide f(p) on the average HVSRFAS curve as a priority, ideally together with the average HVSRFAS curve in site characterization. Y1 - 2020 U6 - https://doi.org/10.1785/0120190186 SN - 0037-1106 SN - 1943-3573 VL - 110 IS - 2 SP - 427 EP - 440 PB - Seismological Society of America CY - El Cerito, Calif. ER - TY - JOUR A1 - Zhou, Renjie A1 - Aitchison, Jonathan C. A1 - Lokho, Kapesa A1 - Sobel, Edward A1 - Feng, Yuexing A1 - Zhao, Jian-xin T1 - Unroofing the Ladakh Batholith: constraints from autochthonous molasse of the Indus Basin, NW Himalaya JF - Journal of the Geological Society N2 - The Indus Molasse records orogenic sedimentation associated with uplift and erosion of the southern margin of Asia in the course of ongoing India-Eurasia collision. Detailed field investigation clarifies the nature and extent of the depositional contact between this molasse and the underlying basement units. We report the first dataset on detrital zircon U-Pb ages, Hf isotopes and apatite U-Pb ages for the autochthonous molasse in the Indus Suture Zone. A latest Oligocene depositional age is proposed on the basis of the youngest detrital zircon U-Pb age peak and is consistent with published biostratigraphic data. Multiple provenance indicators suggest exclusively northerly derivation with no input from India in the lowermost parts of the section. The results provide constraints on the uplift and erosion history of the Ladakh Range following the initial India-Asia collision. Y1 - 2020 U6 - https://doi.org/10.1144/jgs2019-188 SN - 0016-7649 SN - 2041-479X VL - 177 IS - 4 SP - 818 EP - 825 PB - Geological Society (London) CY - London ER - TY - JOUR A1 - Zhang, Xiaolin A1 - Yang, Xiaoqiang A1 - Jomaa, Seifeddine A1 - Rode, Michael T1 - Analyzing impacts of seasonality and landscape gradient on event-scale nitrate-discharge dynamics based on nested high-frequency monitoring JF - Journal of hydrology N2 - Increasingly available high-frequency data during storm events, when hydrological dynamics most likely activate nitrate storage-flux exchanges, reveal insights into catchment nitrate dynamics. In this study, we explored impacts of seasonality and landscape gradients on nitrate concentration-discharge (C-Q) hysteresis patterns in the Selke catchment, central Germany, which has heterogeneous combinations of meteorological, hydrogeological and land use conditions. Three nested gauging stations established along the main Selke River captured flow and nitrate export dynamics from the uppermost subcatchment (mixed forest and arable land), middle subcatchment (pure steep forest) and lowermost subcatchment (arable and urban land). We collected continuous high-frequency (15-min) discharge and nitrate concentration data from 2012 to 2017 and analyzed the 223 events detected at all three stations. A dominant hysteresis pattern in the uppermost and middle subcatchments was counter-clockwise and combined with an accretion effect, indicating many proximal and mobilized distal nitrate sources. However, 66% of all events at the catchment outlet experienced a dilution effect, possibly due to mechanisms that vary seasonally. During wetting/wet periods (October-March), it was combined mainly with a counter-clockwise pattern due to the dominance of event runoff volume from the uppermost and middle subcatchments. During drying/dry periods (April-September), however, it was combined mainly with a clockwise pattern due to occasional quick surface flows from lowland near-stream urban areas. In addition, the clockwise hysteresis occurred mainly from May-October during mostly drying/dry periods at all three sites, indicating little distal nitrate transport in response to the low terrestrial hydrological connectivity, especially in the lowermost dry and flat sub-catchment. This comprehensive analysis (i.e., clockwise vs. counter-clockwise, accretion vs. dilution) enables in-depth analysis of nitrate export mechanisms during certain periods under different landscape conditions. Specific combination of C-Q relationships could identify target locations for agricultural management actions that decrease nitrate output. Therefore, we strongly encourage long-term multisite and high-frequency monitoring strategies in heterogeneous nested catchment(s), which can help understand process mechanisms, generate data for physical-based water-quality modeling and provide guidance for water and agricultural management. KW - nitrate export dynamic KW - C-Q relationship KW - hysteresis pattern KW - high-frequency data KW - landscape effect KW - seasonality effect Y1 - 2020 U6 - https://doi.org/10.1016/j.jhydrol.2020.125585 SN - 0022-1694 SN - 1879-2707 VL - 591 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Zhang, Liyu A1 - Chen, Daizhao A1 - Kuang, Guodun A1 - Guo, Zenghui A1 - Zhang, Gongjing A1 - Wang, Xia T1 - Persistent oxic deep ocean conditions and frequent volcanic activities during the Frasnian-Famennian transition recorded in South China JF - Global and planetary change N2 - The Frasnian-Famennian (F-F) transition of Late Devonian was a critical episode in geological history, recording a major mass extinction event. In this study, we focus on an F-F succession from a deep marine context in Bancheng, southern Guangxi, South China, to investigate coeval changes in pelagic environments of the Paleo-Tethys Ocean. The studied succession is exclusively composed of bedded cherts intercalated with multiple siliceous volcanic ash beds. A SIMS zircon U-Pb Concordia age of 367.8 +/- 2.5 Ma is reported for a tuffaceous layer slightly above the F-F boundary. Geochemical ratios of Al/(Al + Fe + Mn), Ce/Ce*, Y/Ho, and Al, Fe contents in bedded cherts indicate that they are of predominantly biogenic/chemical origin with some terrigenous inputs. Negligible enrichment of redox sensitive elements (Mo, U, V) and low V/Cr ratios (<2) suggest persistently oxic conditions existed in the deep pelagic basin at Bancheng, South China during the F-F transition. These findings call into question the widely held hypothesis that marine anoxia was the primary killing mechanism for the F-F crisis. In contrast, multiple tuffaceous layers throughout the F-F boundary succession indicate frequent volcanic activity, which could have released massive amounts of greenhouse gases into the atmosphere, inducing climate warming. This scenario may have increased continental weathering and riverine fluxes into the ocean, reconciling the increases in Al2O3 content and Al/(Al + Fe + Mn) ratio across the F-F boundary. Documentation of persistently oxic conditions and frequent volcanic activitiy provides new perspectives on the inter-relationship between volcanism, climate, and oceanic redox fluctuation during the F-F biotic crisis. KW - Late Devonian KW - Bedded chert KW - Major and trace elements KW - Deep ocean redox condition KW - Volcanic activity KW - Zircon U-Pb dating Y1 - 2020 U6 - https://doi.org/10.1016/j.gloplacha.2020.103350 SN - 0921-8181 VL - 195 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Zeeden, Christian A1 - Obreht, Igor A1 - Veres, Daniel A1 - Kaboth-Bahr, Stefanie A1 - Hošek, Jan A1 - Marković, Slobodan B. A1 - Bösken, Janina A1 - Lehmkuhl, Frank A1 - Rolf, Christian A1 - Hambach, Ulrich T1 - Smoothed millennial-scale palaeoclimatic reference data as unconventional comparison targets: Application to European loess records JF - Scientific Reports N2 - Millennial-scale palaeoclimate variability has been documented in various terrestrial and marine palaeoclimate proxy records throughout the Northern Hemisphere for the last glacial cycle. Its clear expression and rapid shifts between different states of climate (Greenland Interstadials and Stadials) represents a correlation tool beyond the resolution of e.g. luminescence dating, especially relevant for terrestrial deposits. Usually, comparison of terrestrial proxy datasets and the Greenland ice cores indicates a complex expression of millennial-scale climate variability as recorded in terrestrial geoarchives including loess. Loess is the most widespread terrestrial geoarchive of the Quaternary and especially widespread over Eurasia. However, loess often records a smoothed representation of millennial-scale variability without all fidelity when compared to the Greenland data, this being a relevant limiting feature in integrating loess with other palaeoclimate records. To better understand the loess proxy-response to millennial-scale climate variability, we simulate a proxy signal smoothing by natural processes through application of low-pass filters of delta O-18 data from Greenland, a high-resolution palaeoclimate reference record, alongside speleothem isotope records from the Black Sea-Mediterranean region. We show that low-pass filters represent rather simple models for better constraining the expression of millennial-scale climate variability in low sedimentation environments, and in sediments where proxy-response signals are most likely affected by natural smoothing (by e.g. bioturbation). Interestingly, smoothed datasets from Greenland and the Black Sea-Mediterranean region are most similar in the last similar to 15 ka and between similar to 50-30 ka. Between similar to 30-15 ka, roughly corresponding to the Last Glacial Maximum and the deglaciation, the records show dissimilarities, challenging the construction of robust correlative time-scales in this age range. From our analysis it becomes apparent that patterns of palaeoclimate signals in loess-palaeosol sequences often might be better explained by smoothed Greenland reference data than the original high-resolution Greenland dataset, or other reference data. This opens the possibility to better assess the temporal resolution and palaeoclimate potential of loess-palaeosol sequences in recording supra-regional climate patterns, as well as to securely integrate loess with other chronologically better-resolved palaeoclimate records. KW - last glacial period KW - Western Interior Basin KW - high-resolution record KW - Greenland ice cores KW - paleosol sequence KW - time-scale KW - Chinese loess KW - astronomical calibration KW - chronology (AICC2012) KW - Antarctic ice Y1 - 2020 VL - 10 IS - 1 PB - Springer Nature CY - Berlin ER - TY - GEN A1 - Zeeden, Christian A1 - Obreht, Igor A1 - Veres, Daniel A1 - Kaboth-Bahr, Stefanie A1 - Hošek, Jan A1 - Marković, Slobodan B. A1 - Bösken, Janina A1 - Lehmkuhl, Frank A1 - Rolf, Christian A1 - Hambach, Ulrich T1 - Smoothed millennial-scale palaeoclimatic reference data as unconventional comparison targets: Application to European loess records T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Millennial-scale palaeoclimate variability has been documented in various terrestrial and marine palaeoclimate proxy records throughout the Northern Hemisphere for the last glacial cycle. Its clear expression and rapid shifts between different states of climate (Greenland Interstadials and Stadials) represents a correlation tool beyond the resolution of e.g. luminescence dating, especially relevant for terrestrial deposits. Usually, comparison of terrestrial proxy datasets and the Greenland ice cores indicates a complex expression of millennial-scale climate variability as recorded in terrestrial geoarchives including loess. Loess is the most widespread terrestrial geoarchive of the Quaternary and especially widespread over Eurasia. However, loess often records a smoothed representation of millennial-scale variability without all fidelity when compared to the Greenland data, this being a relevant limiting feature in integrating loess with other palaeoclimate records. To better understand the loess proxy-response to millennial-scale climate variability, we simulate a proxy signal smoothing by natural processes through application of low-pass filters of delta O-18 data from Greenland, a high-resolution palaeoclimate reference record, alongside speleothem isotope records from the Black Sea-Mediterranean region. We show that low-pass filters represent rather simple models for better constraining the expression of millennial-scale climate variability in low sedimentation environments, and in sediments where proxy-response signals are most likely affected by natural smoothing (by e.g. bioturbation). Interestingly, smoothed datasets from Greenland and the Black Sea-Mediterranean region are most similar in the last similar to 15 ka and between similar to 50-30 ka. Between similar to 30-15 ka, roughly corresponding to the Last Glacial Maximum and the deglaciation, the records show dissimilarities, challenging the construction of robust correlative time-scales in this age range. From our analysis it becomes apparent that patterns of palaeoclimate signals in loess-palaeosol sequences often might be better explained by smoothed Greenland reference data than the original high-resolution Greenland dataset, or other reference data. This opens the possibility to better assess the temporal resolution and palaeoclimate potential of loess-palaeosol sequences in recording supra-regional climate patterns, as well as to securely integrate loess with other chronologically better-resolved palaeoclimate records. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1187 KW - last glacial period KW - Western Interior Basin KW - high-resolution record KW - Greenland ice cores KW - paleosol sequence KW - time-scale KW - Chinese loess KW - astronomical calibration KW - chronology (AICC2012) KW - Antarctic ice Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-524271 SN - 1866-8372 IS - 1 ER - TY - THES A1 - Zeckra, Martin T1 - Seismological and seismotectonic analysis of the northwestern Argentine Central Andean foreland N2 - After a severe M W 5.7 earthquake on October 17, 2015 in El Galpón in the province of Salta NW Argentina, I installed a local seismological network around the estimated epicenter. The network covered an area characterized by inherited Cretaceous normal faults and neotectonic faults with unknown recurrence intervals, some of which may have been reactivated normal faults. The 13 three-component seismic stations recorded data continuously for 15 months. The 2015 earthquake took place in the Santa Bárbara System of the Andean foreland, at about 17km depth. This region is the easternmost morphostructural region of the central Andes. As a part of the broken foreland, it is bounded to the north by the Subandes fold-and-thrust belt and the Sierras Pampeanas to the south; to the east lies the Chaco-Paraná basin. A multi-stage morphotectonic evolution with thick-skinned basement uplift and coeval thin-skinned deformation in the intermontane basins is suggested for the study area. The release of stresses associated with the foreland deformation can result in strong earthquakes, as the study area is known for recurrent and historical, destructive earthquakes. The available continuous record reaches back in time, when the strongest event in 1692 (magnitude 7 or intensity IX) destroyed the city of Esteco. Destructive earthquakes and surface deformation are thus a hallmark of this part of the Andean foreland. With state-of-the-art Python packages (e.g. pyrocko, ObsPy), a semi-automatic approach is followed to analyze the collected continuous data of the seismological network. The resulting 1435 hypocenter locations consist of three different groups: 1.) local crustal earthquakes (nearly half of the events belong to this group), 2.) interplate activity, of regional distance in the slab of the Nazca-plate, and 3.) very deep earthquakes at about 600km depth. My major interest focused on the first event class. Those crustal events are partly aftershock events of the El Galpón earthquake and a second earthquake, in the south of the same fault. Further events can be considered as background seismicity of other faults within the study area. Strikingly, the seismogenic zone encompass the whole crust and propagates brittle deformation down, close to the Moho. From the collected seismological data, a local seismic velocity model is estimated, using VELEST. After the execution of various stability tests, the robust minimum 1D-velocity model implies guiding values for the composition of the local, subsurface structure of the crust. Afterwards, performing a hypocenter relocation enables the assignment of individual earthquakes to aftershock clusters or extended seismotectonic structures. This allows the mapping of previously unknown seismogenic faults. Finally, focal mechanisms are modeled for events with acurately located hypocenters, using the newly derived local velocity model. A compressive regime is attested by the majority of focal mechanisms, while the strike direction of the individual seismogenic structures is in agreement with the overall north – south orientation of the Central Andes, its mountain front, and individual mountain ranges in the southern Santa-Bárbara-System. N2 - Nach einem schweren Erdbeben der Magnitude M W 5.7 am 17. Oktober 2015 in El Galpón, in der Provinz Salta im Nordwesten Argentiniens, habe ich ein lokales seismologisches Netzwerk, um das vermutete Epizentrum herum, aufgebaut. Dabei haben 13 Stationen kontinuierlich für 15 Monate gemessen. Das Netzwerk wurde in einem Gebiet installiert, welches durch tektonische Störungen charakterisiert ist, die entweder in der Kreidezeit zunächst als Abschiebungen initiiert und später als Aufschiebungen reaktiviert wurden oder in der geologischen jüngeren Vergangenheit erst entstanden sind. Die Intervallzeiten zwischen zwei Erdbeben sind dabei häufig unbekannt. Das Erdbeben von 2015 trat im Santa-Barbara-System im Argentinischen Vorland, 17 km unter der Erdoberfläche auf. Diese Region ist die östlichste strukturgeologische Provinz der Zentralanden und dem broken-foreland-Typus zuzuordnen. Im Norden schließt sich der Bolivianische Faltengürtel (Sierras Subandinas) und im Süden die Sierras Pampeanas an; im Osten liegt das Chaco-Paraná Becken. Eine mehrstufige morphotektonische Entwicklung wird hier vermutet, bei der das Grundgebirge durch als thick-skinned bezeichnete Deformation herausgehoben wurde und die dazwischen liegenden Intermontanbecken gleichzeitig Deformation des Typs thin-skinned erfahren haben. Die plötzliche Spannungsfreisetzung, die mit dieser Vorlanddeformation einhergeht, kann zu starken Erdbeben führen. Das Untersuchungsgebiet ist für wiederkehrende und historische, zerstörerische Erdbeben bekannt. Der zur Verfügung stehenden Aufzeichnungen reichen bis in das Jahr 1692 zurück, als ein Erdbeben der Magnitude M 7 (oder Intensität IX) die Stadt Esteco zerstörte. Daher sind zerstörerische Erdbeben ein besonderes Kennzeichen in diesem Teil des Andenvorlands. Für die Analyse der im seismologischen Netzwerk aufgezeichneten kontinuierlichen Daten wurde ein semiautomatischer Ansatz verfolgt, der mittels hochmoderner Python-Bibliotheken informationstechnisch umgesetzt wurde. Die resultierenden 1435 Erdbeben bestehen aus drei verschiedenen Gruppen: 1.) lokale Erdbeben in der Erdkruste (die etwa die Hälfte aller Events ausmachen), 2.) weiter entfernte Interplattenaktivität, die durch die Subduktion der Nazca-Platte unter den Südamerikanischen Kontinent hervorgerufen wird und 3.) sehr tiefen Erdbeben in etwa 600 km Tiefe. Mein Hauptaugenmerk lag dabei auf der ersten Gruppe. Diese krustalen Ereignisse sind teilweise Nachbeben des El Galpón Erdbebens und eines weiteren Bebens, welches sich weiter im Süden an der gleichen Störung ereignete. Die restlichen Beben können der allgemeinen Hintergrundaktivität entlang weiterer Störungen im Untersuchungsgebiet zugeschrieben werden. Beachtenswert ist dabei der Umstand, dass die Erdbebenaktivität in der gesamten Kruste beobachtet werden kann und sich dadurch die Deformation bis a fast an den Erdmantel ausbreitet. Mit den gesammelten Daten kann, unter der Verwendung der VELEST Software, ein lokales seismisches Geschwindigkeitsmodell bestimmt werden. Nach der Durchführung verschiedener Stabilitätstests, können aus dem robusten eindimensionalen Modell Richtwerte für die Zusammensetzung und den Aufbau der Erdkruste gewonnen werden. Dieanschließende Relokalisierung von Erdbebenherden erlaubt die Zuordnung einzelner Erdbeben zu Erdbebenclustern oder ausgedehnten seismotektonischen Strukturen. Dadurch können sogar zuvor unbekannte seismogene Störungen kartiert werden. Schlussendlich, werden Herdflächenlösungen für Beben mit präzise lokalisierten Erdbebenherden und unter der Einbeziehung des neu bestimmten lokalen Geschwindigkeitsmodells modelliert. Der Großteil der resultierenden Lösungen bestätigt das vorherrschende kompressive Regime. Das Streichen der einzelnen seismogenen Strukturen stimmt größtenteils mit der allgemeinen Nord – Süd Ausrichtugn der Zentralanden, ihrer Gebirgsfront und den einzelnen Höhenzügen im Santa-Barbará-System überein. T2 - Seismologische und Seismotektonische Analyse des Vorlandsystems der nordwestargentinischen Zentralanden KW - Seismology KW - Seismotektonik KW - Geophysics KW - Andes KW - Geosciences KW - Argentina KW - Anden KW - Seismologie KW - Geophysik KW - Geowissenschaften KW - Argentinien Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-473240 ER - TY - GEN A1 - Zapata, Sebastian A1 - Sobel, Edward A1 - Del Papa, Cecilia A1 - Glodny, Johannes T1 - Upper Plate Controls on the Formation of Broken Foreland Basins in the Andean Retroarc Between 26°S and 28°S BT - From Cretaceous Rifting to Paleogene and Miocene Broken Foreland Basins T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Marked along-strike changes in stratigraphy, mountain belt morphology, basement exhumation, and deformation styles characterize the Andean retroarc; these changes have previously been related to spatiotemporal variations in the subduction angle. We modeled new apatite fission track and apatite (U-Th-Sm)/He data from nine ranges located between 26 degrees S and 28 degrees S. Using new and previously published data, we constructed a Cretaceous to Pliocene paleogeographic model that delineates a four-stage tectonic evolution: extensional tectonics during the Cretaceous (120-75 Ma), the formation of a broken foreland basin between 55 and 30 Ma, reheating due to burial beneath sedimentary rocks (18-13 Ma), and deformation, exhumation, and surface uplift during the Late Miocene and the Pliocene (13-3 Ma). Our model highlights how preexisting upper plate structures control the deformation patterns of broken foreland basins. Because retroarc deformation predates flat-slab subduction, we propose that slab anchoring may have been the precursor of Eocene-Oligocene compression in the Andean retroarc. Our model challenges models which consider broken foreland basins and retroarc deformation in the NW Argentinian Andes to be directly related to Miocene flat subduction. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1215 KW - Northern Sierras Pampeanas KW - Fission-track thermochronology KW - Middle Eocene deformation KW - Santa-Barbara system KW - flat-slab subduction KW - tectonic inversion KW - Apatite (U-TH)/HE KW - Puna Plateau KW - radiation-damage KW - length measurements Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-523823 SN - 1866-8372 IS - 7 ER - TY - JOUR A1 - Zapata, Sebastian A1 - Sobel, Edward A1 - Del Papa, Cecilia A1 - Glodny, Johannes T1 - Upper Plate Controls on the Formation of Broken Foreland Basins in the Andean Retroarc Between 26°S and 28°S BT - From Cretaceous Rifting to Paleogene and Miocene Broken Foreland Basins JF - Geochemistry, Geophysics, Geosystems N2 - Marked along-strike changes in stratigraphy, mountain belt morphology, basement exhumation, and deformation styles characterize the Andean retroarc; these changes have previously been related to spatiotemporal variations in the subduction angle. We modeled new apatite fission track and apatite (U-Th-Sm)/He data from nine ranges located between 26 degrees S and 28 degrees S. Using new and previously published data, we constructed a Cretaceous to Pliocene paleogeographic model that delineates a four-stage tectonic evolution: extensional tectonics during the Cretaceous (120-75 Ma), the formation of a broken foreland basin between 55 and 30 Ma, reheating due to burial beneath sedimentary rocks (18-13 Ma), and deformation, exhumation, and surface uplift during the Late Miocene and the Pliocene (13-3 Ma). Our model highlights how preexisting upper plate structures control the deformation patterns of broken foreland basins. Because retroarc deformation predates flat-slab subduction, we propose that slab anchoring may have been the precursor of Eocene-Oligocene compression in the Andean retroarc. Our model challenges models which consider broken foreland basins and retroarc deformation in the NW Argentinian Andes to be directly related to Miocene flat subduction. KW - Northern Sierras Pampeanas KW - Fission-track thermochronology KW - Middle Eocene deformation KW - Santa-Barbara system KW - flat-slab subduction KW - tectonic inversion KW - Apatite (U-TH)/HE KW - Puna Plateau KW - radiation-damage KW - length measurements Y1 - 2019 VL - 21 IS - 7 PB - John Wiley & Sons, Inc. CY - New Jersey ER - TY - JOUR A1 - Wolf, Sabina A1 - Pham, My A1 - Matthews, Nathanial A1 - Bubeck, Philip T1 - Understanding the implementation gap BT - policy-makers’ perceptions of ecosystem-based adaptation in Central Vietnam JF - Climate & development N2 - In recent years, nature-based solutions are receiving increasing attention in the field of disaster risk reduction and climate change adaptation as inclusive, no regret approaches. Ecosystem-based adaptation (EbA) can mitigate the impacts of climate change, build resilience and tackle environmental degradation thereby supporting the targets set by the 2030 Agenda, the Paris Agreement and the Sendai Framework. Despite these benefits, EbA is still rarely implemented in practice. To better understand the barriers to implementation, this research examines policy-makers' perceptions of EbA, using an extended version of Protection Motivation Theory as an analytical framework. Through semi-structured interviews with policy-makers at regional and provincial level in Central Vietnam, it was found that EbA is generally considered a promising response option, mainly due to its multiple ecosystem-service benefits. The demand for EbA measures was largely driven by the perceived consequences of natural hazards and climate change. Insufficient perceived response efficacy and time-lags in effectiveness for disaster risk reduction were identified as key impediments for implementation. Pilot projects and capacity building on EbA are important means to overcome these perceptual barriers. This paper contributes to bridging the knowledge-gap on political decision-making regarding EbA and can, thereby, promote its mainstreaming into policy plans. KW - climate change KW - ecosystem-based adaptation KW - risk perception KW - protection KW - motivation theory KW - decision making Y1 - 2020 U6 - https://doi.org/10.1080/17565529.2020.1724068 SN - 1756-5529 SN - 1756-5537 VL - 13 IS - 1 SP - 81 EP - 94 PB - Taylor & Francis LTD CY - Abingdon ER - TY - JOUR A1 - Wietzke, Luzie M. A1 - Merz, Bruno A1 - Gerlitz, Lars A1 - Kreibich, Heidi A1 - Guse, Björn A1 - Castellarin, Attilio A1 - Vorogushyn, Sergiy T1 - Comparative analysis of scalar upper tail indicators JF - Hydrological sciences journal = Journal des sciences hydrologiques N2 - Different upper tail indicators exist to characterize heavy tail phenomena, but no comparative study has been carried out so far. We evaluate the shape parameter (GEV), obesity index, Gini index and upper tail ratio (UTR) against a novel benchmark of tail heaviness - the surprise factor. Sensitivity analyses to sample size and changes in scale-to-location ratio are carried out in bootstrap experiments. The UTR replicates the surprise factor best but is most uncertain and only comparable between records of similar length. For samples with symmetric Lorenz curves, shape parameter, obesity and Gini indices provide consistent indications. For asymmetric Lorenz curves, however, the first two tend to overestimate, whereas Gini index tends to underestimate tail heaviness. We suggest the use of a combination of shape parameter, obesity and Gini index to characterize tail heaviness. These indicators should be supported with calculation of the Lorenz asymmetry coefficients and interpreted with caution. KW - upper tail behaviour KW - heavy-tailed distributions KW - extremes KW - diagnostics KW - surprise Y1 - 2020 U6 - https://doi.org/10.1080/02626667.2020.1769104 SN - 0262-6667 SN - 2150-3435 VL - 65 IS - 10 SP - 1625 EP - 1639 PB - Routledge, Taylor & Francis Group CY - Abingdon ER - TY - JOUR A1 - Wieczorek, Mareike A1 - Herzschuh, Ulrike T1 - Compilation of relative pollen productivity (RPP) estimates and taxonomically harmonised RPP datasets for single continents and Northern Hemisphere extratropics JF - Earth system science data : ESSD N2 - Relative pollen productivity (RPP) estimates are fractionate values, often in relation to Poaceae, that allow vegetation cover to be estimated from pollen counts with the help of models. RPP estimates are especially used in the scientific community in Europe and China, with a few studies in North America. Here we present a comprehensive compilation of available northern hemispheric RPP studies and their results arising from 51 publications with 60 sites and 131 taxa. This compilation allows scientists to identify data gaps in need of further RPP analyses but can also aid them in finding an RPP set for their study region. We also present a taxonomically harmonised, unified RPP dataset for the Northern Hemisphere and subsets for North America (including Greenland), Europe (including arctic Russia), and China, which we generated from the available studies. The unified dataset gives the mean RPP for 55 harmonised taxa as well as fall speeds, which are necessary to reconstruct vegetation cover from pollen counts and RPP values. Data are openly available at https://doi.org/10.1594/PANGAEA.922661 (Wieczorek and Herzschuh, 2020). Y1 - 2020 U6 - https://doi.org/10.5194/essd-12-3515-2020 SN - 1866-3508 SN - 1866-3516 VL - 12 IS - 4 SP - 3515 EP - 3528 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Wetzel, Maria A1 - Kempka, Thomas A1 - Kühn, Michael T1 - Hydraulic and mechanical impacts of pore space alterations within a sandstone quantified by a flow velocity-dependent precipitation approach JF - Materials N2 - Geochemical processes change the microstructure of rocks and thereby affect their physical behaviour at the macro scale. A micro-computer tomography (micro-CT) scan of a typical reservoir sandstone is used to numerically examine the impact of three spatial alteration patterns on pore morphology, permeability and elastic moduli by correlating precipitation with the local flow velocity magnitude. The results demonstrate that the location of mineral growth strongly affects the permeability decrease with variations by up to four orders in magnitude. Precipitation in regions of high flow velocities is characterised by a predominant clogging of pore throats and a drastic permeability reduction, which can be roughly described by the power law relation with an exponent of 20. A continuous alteration of the pore structure by uniform mineral growth reduces the permeability comparable to the power law with an exponent of four or the Kozeny-Carman relation. Preferential precipitation in regions of low flow velocities predominantly affects smaller throats and pores with a minor impact on the flow regime, where the permeability decrease is considerably below that calculated by the power law with an exponent of two. Despite their complete distinctive impact on hydraulics, the spatial precipitation patterns only slightly affect the increase in elastic rock properties with differences by up to 6.3% between the investigated scenarios. Hence, an adequate characterisation of the spatial precipitation pattern is crucial to quantify changes in hydraulic rock properties, whereas the present study shows that its impact on elastic rock parameters is limited. The calculated relations between porosity and permeability, as well as elastic moduli can be applied for upscaling micro-scale findings to reservoir-scale models to improve their predictive capabilities, what is of paramount importance for a sustainable utilisation of the geological subsurface. KW - Bentheim sandstone KW - digital rock physics KW - micro-CT KW - elastic properties KW - permeability KW - precipitation Y1 - 2020 U6 - https://doi.org/10.3390/ma13143100 SN - 1996-1944 VL - 13 IS - 14 PB - MDPI CY - Basel ER - TY - JOUR A1 - Weiss, Jonathan R. A1 - Walters, Richard J. A1 - Morishita, Yu A1 - Wright, Tim J. A1 - Lazecky, Milan A1 - Wang, Hua A1 - Hussain, Ekbal A1 - Hooper, Andrew J. A1 - Elliott, John R. A1 - Rollins, Chris A1 - Yu, Chen A1 - Gonzalez, Pablo J. A1 - Spaans, Karsten A1 - Li, Zhenhong A1 - Parsons, Barry T1 - High-resolution surface velocities and strain for Anatolia from Sentinel-1 InSAR and GNSS data JF - Geophysical research letters N2 - Measurements of present-day surface deformation are essential for the assessment of long-term seismic hazard. The European Space Agency's Sentinel-1 satellites enable global, high-resolution observation of crustal motion from Interferometric Synthetic Aperture Radar (InSAR). We have developed automated InSAR processing systems that exploit the first similar to 5 years of Sentinel-1 data to measure surface motions for the similar to 800,000-km(2) Anatolian region. Our new 3-D velocity and strain rate fields illuminate deformation patterns dominated by westward motion of Anatolia relative to Eurasia, localized strain accumulation along the North and East Anatolian Faults, and rapid vertical signals associated with anthropogenic activities and to a lesser extent extension across the grabens of western Anatolia. We show that automatically processed Sentinel-1 InSAR data can characterize details of the velocity and strain rate fields with high resolution and accuracy over large regions. These results are important for assessing the relationship between strain accumulation and release in earthquakes.
Plain Language Summary Satellite-based measurements of small rates of motion of the Earth's surface made at high spatial resolutions and over large areas are important for many geophysical applications including improving earthquake hazard models. We take advantage of recent advances in geodetic techniques in order to measure surface velocities and tectonic strain accumulation across the Anatolia region, including the highly seismogenic and often deadly North Anatolian Fault. We show that by combining Sentinel-1 Interferometric Synthetic Aperture Radar (InSAR) data with Global Navigation Satellite System (GNSS) measurements we can enhance our view of surface deformation associated with active tectonics, the earthquake cycle, and anthropogenic processes. Y1 - 2020 U6 - https://doi.org/10.1029/2020GL087376 SN - 0094-8276 SN - 1944-8007 VL - 47 IS - 17 PB - American Geophysical Union CY - Washington ER -