@article{KienzlerFalterThieken2015, author = {Kienzler, Sarah and Falter, Daniela and Thieken, Annegret}, title = {Zusammenwirken von staatlicher und privater Vorsorge}, series = {Das Hochwasser im Juni 2013 : Bew{\"a}hrungsprobe f{\"u}r das Hochwasserrisikomanagement in Deutschland}, journal = {Das Hochwasser im Juni 2013 : Bew{\"a}hrungsprobe f{\"u}r das Hochwasserrisikomanagement in Deutschland}, publisher = {Deutsches Komitee Katastrophenvorsorge}, address = {Bonn}, isbn = {978-3-933181-62-6}, pages = {110 -- 120}, year = {2015}, language = {de} } @misc{RohrmannHeermanceKappetal.2015, author = {Rohrmann, Alexander and Heermance, Richard and Kapp, Paul and Cai, Fulong}, title = {Wind as the primary driver of erosion in the Qaidam Basin, China (vol 374, pg 1, 2013)}, series = {Earth \& planetary science letters}, volume = {432}, journal = {Earth \& planetary science letters}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0012-821X}, doi = {10.1016/j.epsl.2015.10.011}, pages = {501 -- 501}, year = {2015}, language = {en} } @article{HuangDupontNivetLippertetal.2015, author = {Huang, Wentao and Dupont-Nivet, Guillaume and Lippert, Peter C. and van Hinsbergen, Douwe J. J. and Dekkers, Mark J. and Waldrip, Ross and Ganerod, Morgan and Li, Xiaochun and Guo, Zhaojie and Kapp, Paul}, title = {What was the Paleogene latitude of the Lhasa terrane? A reassessment of the geochronology and paleomagnetism of Linzizong volcanic rocks (Linzhou basin, Tibet)}, series = {Tectonics}, volume = {34}, journal = {Tectonics}, number = {3}, publisher = {American Geophysical Union}, address = {Washington}, issn = {0278-7407}, doi = {10.1002/2014TC003787}, pages = {594 -- 622}, year = {2015}, abstract = {The Paleogene latitude of the Lhasa terrane (southern Tibet) can constrain the age of the onset of the India-Asia collision. Estimates for this latitude, however, vary from 5 degrees N to 30 degrees N, and thus, here, we reassess the geochronology and paleomagnetism of Paleogene volcanic rocks from the Linzizong Group in the Linzhou basin. The lower and upper parts of the section previously yielded particularly conflicting ages and paleolatitudes. We report consistent Ar-40/Ar-39 and U-Pb zircon dates of similar to 52Ma for the upper Linzizong, and Ar-40/Ar-39 dates (similar to 51Ma) from the lower Linzizong are significantly younger than U-Pb zircon dates (64-63Ma), suggesting that the lower Linzizong was thermally and/or chemically reset. Paleomagnetic results from 24 sites in lower Linzizong confirm a low apparent paleolatitude of similar to 5 degrees N, compared to the upper part (similar to 20 degrees N) and to underlying Cretaceous strata (similar to 20 degrees N). Detailed rock magnetic analyses, end-member modeling of magnetic components, and petrography from the lower and upper Linzizong indicate widespread secondary hematite in the lower Linzizong, whereas hematite is rare in upper Linzizong. Volcanic rocks of the lower Linzizong have been hydrothermally chemically remagnetized, whereas the upper Linzizong retains a primary remanence. We suggest that remagnetization was induced by acquisition of chemical and thermoviscous remanent magnetizations such that the shallow inclinations are an artifact of a tilt correction applied to a secondary remanence in lower Linzizong. We estimate that the Paleogene latitude of Lhasa terrane was 204 degrees N, consistent with previous results suggesting that India-Asia collision likely took place by similar to 52Ma at similar to 20 degrees N.}, language = {en} } @misc{CesareAcostaVigilBartolietal.2015, author = {Cesare, Bernardo and Acosta-Vigil, Antonio and Bartoli, Omar and Ferrero, Silvio}, title = {What can we learn from melt inclusions in migmatites and granulites?}, series = {Lithos : an international journal of mineralogy, petrology, and geochemistry}, volume = {239}, journal = {Lithos : an international journal of mineralogy, petrology, and geochemistry}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0024-4937}, doi = {10.1016/j.lithos.2015.09.028}, pages = {186 -- 216}, year = {2015}, abstract = {With less than two decades of activity, research on melt inclusions (MI) in crystals from rocks that have undergone crustal anatexis - migmatites and granulites - is a recent addition to crustal petrology and geochemistry. Studies on this subject started with glassy inclusions in anatectic crustal enclaves in lavas, and then progressed to regionally metamorphosed and partially melted crustal rocks, where melt inclusions are normally crystallized into a cryptocrystalline aggregate (nanogranitoid). Since the first paper on melt inclusions in the granulites of the Kerala Khondalite Belt in 2009, reported and studied occurrences are already a few tens. Melt inclusions in migmatites and granulites show many analogies with their more common and long studied counterparts in igneous rocks, but also display very important differences and peculiarities, which are the subject of this review. Microstructurally, melt inclusions in anatectic rocks are small, commonly 10 mu m in diameter, and their main mineral host is peritectic garnet, although several other hosts have been observed. Inclusion contents vary from glass in enclaves that were cooled very rapidly from supersolidus temperatures, to completely crystallized material in slowly cooled regional migmatites. The chemical composition of the inclusions can be analyzed combining several techniques (SEM, EMP, NanoSIMS, LA-ICP-MS), but in the case of crystallized inclusions the experimental remelting under confining pressure in a piston cylinder is a prerequisite. The melt is generally granitic and peraluminous, although granodioritic to trondhjemitic compositions have also been found. Being mostly primary in origin, inclusions attest for the growth of their peritectic host in the presence of melt. As a consequence, the inclusions have the unique ability of preserving information on the composition of primary anatectic crustal melts, before they undergo any of the common following changes in their way to produce crustal magmas. For these peculiar features, melt inclusions in migmatites and granulites, largely overlooked so far, have the potential to become a fundamental tool for the study of crustal melting, crustal differentiation, and even the generation of the continental crust. (C) 2015 The Authors. Published by Elsevier B.V.}, language = {en} } @book{OPUS4-7857, title = {Wasser f{\"u}r Arkadien}, editor = {Schmitt, Hanno and Tosch, Frank}, publisher = {Rochow-Museum}, address = {Reckahn}, isbn = {978-3-9809752-7-8}, publisher = {Universit{\"a}t Potsdam}, pages = {135}, year = {2015}, abstract = {Begleitbuch zur Ausstellung im Rochow-Museum Reckahn, vom 6.6.-1.11.2015}, language = {de} } @article{PechKreibichThieken2015, author = {Pech, Ina and Kreibich, Heidi and Thieken, Annegret}, title = {Warnung und Reaktion aus Sicht von Betroffenen}, series = {Das Hochwasser im Juni 2013 : Bew{\"a}hrungsprobe f{\"u}r das Hochwasserrisikomanagement in Deutschland}, journal = {Das Hochwasser im Juni 2013 : Bew{\"a}hrungsprobe f{\"u}r das Hochwasserrisikomanagement in Deutschland}, publisher = {Deutsches Komitee Katastrophenvorsorge}, address = {Bonn}, isbn = {978-3-933181-62-6}, pages = {138 -- 142}, year = {2015}, language = {de} } @article{SeifertWeithoffGaedkeetal.2015, author = {Seifert, Linda I. and Weithoff, Guntram and Gaedke, Ursula and Vos, Matthijs}, title = {Warming-induced changes in predation, extinction and invasion in an ectotherm food web}, series = {Oecologia}, volume = {178}, journal = {Oecologia}, number = {2}, publisher = {Springer}, address = {New York}, issn = {0029-8549}, doi = {10.1007/s00442-014-3211-4}, pages = {485 -- 496}, year = {2015}, abstract = {Climate change will alter the forces of predation and competition in temperate ectotherm food webs. This may increase local extinction rates, change the fate of invasions and impede species reintroductions into communities. Invasion success could be modulated by traits (e.g., defenses) and adaptations to climate. We studied how different temperatures affect the time until extinction of species, using bitrophic and tritrophic planktonic food webs to evaluate the relative importance of predatory overexploitation and competitive exclusion, at 15 and 25 A degrees C. In addition, we tested how inclusion of a subtropical as opposed to a temperate strain in this model food web affects times until extinction. Further, we studied the invasion success of the temperate rotifer Brachionus calyciflorus into the planktonic food web at 15 and 25 A degrees C on five consecutive introduction dates, during which the relative forces of predation and competition differed. A higher temperature dramatically shortened times until extinction of all herbivore species due to carnivorous overexploitation in tritrophic systems. Surprisingly, warming did not increase rates of competitive exclusion among the tested herbivore species in bitrophic communities. Including a subtropical herbivore strain reduced top-down control by the carnivore at high temperature. Invasion attempts of temperate B. calyciflorus into the food web always succeeded at 15 A degrees C, but consistently failed at 25 A degrees C due to voracious overexploitation by the carnivore. Pre-induction of defenses (spines) in B. calyciflorus before the invasion attempt did not change its invasion success at the high temperature. We conclude that high temperatures may promote local extinctions in temperate ectotherms and reduce their chances of successful recovery.}, language = {en} } @article{ThiekenPisi2015, author = {Thieken, Annegret and Pisi, Sebastian}, title = {Vorhersagen und Warnungen im Mai / Juni 2013}, series = {Das Hochwasser im Juni 2013 : Bew{\"a}hrungsprobe f{\"u}r das Hochwasserrisikomanagement in Deutschland}, journal = {Das Hochwasser im Juni 2013 : Bew{\"a}hrungsprobe f{\"u}r das Hochwasserrisikomanagement in Deutschland}, publisher = {Deutsches Komitee Katastrophenvorsorge}, address = {Bonn}, isbn = {978-3-933181-62-6}, pages = {132 -- 137}, year = {2015}, language = {de} } @article{WessonMelnickCisternasetal.2015, author = {Wesson, Robert L. and Melnick, Daniel and Cisternas, Marco and Moreno, Marcos and Ely, Lisa L.}, title = {Vertical deformation through a complete seismic cycle at Isla Santa Maria, Chile}, series = {Nature geoscience}, volume = {8}, journal = {Nature geoscience}, number = {7}, publisher = {Nature Publ. Group}, address = {New York}, issn = {1752-0894}, doi = {10.1038/NGEO2468}, pages = {547 -- U157}, year = {2015}, abstract = {Individual great earthquakes are posited to release the elastic strain energy that has accumulated over centuries by the gradual movement of tectonic plates(1,2). However, knowledge of plate deformation during a complete seismic cycle-two successive great earthquakes and the intervening interseismic period-remains incomplete(3). A complete seismic cycle began in south-central Chile in 1835 with an earthquake of about magnitude 8.5 (refs 4,5) and ended in 2010 with a magnitude 8.8 earthquake(6). During the first earthquake, an uplift of Isla Santa Maria by 2.4 to 3m was documented(4,5). In the second earthquake, the island was uplifted(7) by 1.8 m. Here we use nautical surveys made in 1804, after the earthquake in 1835 and in 1886, together with modern echo sounder surveys and GPS measurements made immediately before and after the 2010 earthquake, to quantify vertical deformation through the complete seismic cycle. We find that in the period between the two earthquakes, Isla Santa Maria subsided by about 1.4 m. We simulate the patterns of vertical deformation with a finite-element model and find that they agree broadly with predictions from elastic rebound theory(2). However, comparison with geomorphic and geologic records of millennial coastline emergence(8,9) reveal that 10-20\% of the vertical uplift could be permanent.}, language = {en} } @article{NiemeyerHerzschuhPestryakova2015, author = {Niemeyer, Bastian and Herzschuh, Ulrike and Pestryakova, Luidmila Agafyevna}, title = {Vegetation and lake changes on the southern Taymyr peninsula, northern Siberia, during the last 300 years inferred from pollen and Pediastrum green algae records}, series = {The Holocene : an interdisciplinary journal focusing on recent environmental change}, volume = {25}, journal = {The Holocene : an interdisciplinary journal focusing on recent environmental change}, number = {4}, publisher = {Sage Publ.}, address = {London}, issn = {0959-6836}, doi = {10.1177/0959683614565954}, pages = {596 -- 606}, year = {2015}, abstract = {Siberian arctic vegetation and lake water communities, known for their temperature dependence, are expected to be particularly impacted by recent climate change and high warming rates. However, decadal information on the nature and strength of recent vegetation change and its time lag to climate signals are rare. In this study, we present a Pb-210/Cs-137 dated pollen and Pediastrum species record from a unnamed lake in the south of the Taymyr peninsula covering the period from AD 1706 to 2011. Thirty-nine palynomorphs and 10 morphotypes of Pediastrum species were studied to assess changes in vegetation and lake conditions as probable responses to climate change. We compared the pollen record with Pediastrum species, which we consider to be important proxies of climate changes. Three pollen assemblage zones characterised by Betula nana, Alnus viridis and Larix gmelinii (1706-1808); herbs such as Cyperaceae, Artemisia or Senecio (1808-1879), and higher abundance of Larix pollen (1955-2011) are visible. Also, three Pediastrum assemblage zones show changes of aquatic conditions: higher abundances of Pediastrum boryanum var. brevicorne (1706-1802); medium abundances of P. kawraiskyi and P. integrum (1802-1840 and 1920-1980), indicating cooler conditions while less eutrophic conditions are indicated by P. boryanum, and a mainly balanced composition with only small changes of cold- and warm-adapted Pediastrum species (1965-2011). In general, compositional Pediastrum species turnover is slightly higher than that indicated by pollen data (0.54 vs 0.34 SD), but both are only minor for this treeline location. In conclusion, the relevance of differentiation of Pediastrum species is promising and can give further insights into the relationship between lakes and their surrounding vegetation transferred onto climatic conditions.}, language = {en} } @article{MatosSilveiraMatiasetal.2015, author = {Matos, Catarina and Silveira, Graca and Matias, Luis and Caldeira, Rita and Ribeiro, M. Luisa and Dias, Nuno A. and Kr{\"u}ger, Frank and Bento dos Santos, Telmo}, title = {Upper crustal structure of Madeira Island revealed from ambient noise tomography}, series = {Journal of volcanology and geothermal research}, volume = {298}, journal = {Journal of volcanology and geothermal research}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0377-0273}, doi = {10.1016/j.jvolgeores.2015.03.017}, pages = {136 -- 145}, year = {2015}, abstract = {We present the first image of the Madeira upper crustal structure, using ambient seismic noise tomography. 16 months of ambient noise, recorded in a dense network of 26 seismometers deployed across Madeira, allowed reconstructing Rayleigh wave Green's functions between receivers. Dispersion analysis was performed in the short period band from 1.0 to 4.0 s. Group velocity measurements were regionalized to obtain 20 tomographic images, with a lateral resolution of 2.0 km in central Madeira. Afterwards, the dispersion curves, extracted from each cell of the 2D group velocity maps, were inverted as a function of depth to obtain a 3D shear wave velocity model of the upper crust, from the surface to a depth of 2.0 km. The obtained 3D velocity model reveals features throughout the island that correlates well with surface geology and island evolution. (C) 2015 Elsevier B.V. All rights reserved.}, language = {en} } @article{JaraMunozMelnick2015, author = {Jara Mu{\~n}oz, Julius and Melnick, Daniel}, title = {Unraveling sea-level variations and tectonic uplift in wave-built marine terraces, Santa Maria Island, Chile}, series = {Quaternary research : an interdisciplinary journal}, volume = {83}, journal = {Quaternary research : an interdisciplinary journal}, number = {1}, publisher = {Elsevier}, address = {San Diego}, issn = {0033-5894}, doi = {10.1016/j.yqres.2014.10.002}, pages = {216 -- 228}, year = {2015}, abstract = {The architecture of coastal sequences in tectonically-active regions results mostly from a combination of sea-level and land-level changes. The objective of this study is to unravel these signals by combining sequence stratigraphy and sedimentology of near-shore sedimentary sequences in wave-built terraces. We focus on Santa Maria Island at the south-central Chile margin, which hosts excellent exposures of coastal sediments from Marine Isotope Stage 3. A novel method based on statistical analysis of grain-size distributions coupled with fades descriptions provided a detailed account of transgressive-regressive cycles. Radiocarbon ages from paleosols constrain the chronology between >53 and similar to 31 cal ka BP. Because the influence of glaciations can be neglected, we calculated relative sea-level curves by tying the onset of deposition on a bedrock abrasion platform to a global sea-level curve. The observed depositional cycles match those predicted for uplift rates between 1.2 and 1.8 m/ka. The studied sedimentary units represent depositional cycles that resulted in reoccupation events of an existing marine terrace. Our study demonstrates wave-built marine terrace deposits along clastic shorelines in temperate regions can be used to distinguish between tectonic uplift and climate-induced sea-level changes.}, language = {en} } @article{OlenBookhagenHoffmannetal.2015, author = {Olen, Stephanie M. and Bookhagen, Bodo and Hoffmann, Bernd and Sachse, Dirk and Adhikari, Danda P. and Strecker, Manfred}, title = {Understanding erosion rates in the Himalayan orogen: A case study from the Arun Valley}, series = {Journal of geophysical research : Earth surface}, volume = {120}, journal = {Journal of geophysical research : Earth surface}, number = {10}, publisher = {American Geophysical Union}, address = {Washington}, issn = {2169-9003}, doi = {10.1002/2014JF003410}, pages = {2080 -- 2102}, year = {2015}, abstract = {Understanding the rates and pattern of erosion is a key aspect of deciphering the impacts of climate and tectonics on landscape evolution. Denudation rates derived from terrestrial cosmogenic nuclides (TCNs) are commonly used to quantify erosion and bridge tectonic (Myr) and climatic (up to several kiloyears) time scales. However, how the processes of erosion in active orogens are ultimately reflected in Be-10 TCN samples remains a topic of discussion. We investigate this problem in the Arun Valley of eastern Nepal with 34 new Be-10-derived catchment-mean denudation rates. The Arun Valley is characterized by steep north-south gradients in topography and climate. Locally, denudation rates increase northward, from <0.2mmyr(-1) to similar to 1.5mmyr(-1) in tributary samples, while main stem samples appear to increase downstream from similar to 0.2mmyr(-1) at the border with Tibet to 0.91mmyr(-1) in the foreland. Denudation rates most strongly correlate with normalized channel steepness (R-2=0.67), which has been commonly interpreted to indicate tectonic activity. Significant downstream decrease of Be-10 concentration in the main stem Arun suggests that upstream sediment grains are fining to the point that they are operationally excluded from the processed sample. This results in Be-10 concentrations and denudation rates that do not uniformly represent the upstream catchment area. We observe strong impacts on Be-10 concentrations from local, nonfluvial geomorphic processes, such as glaciation and landsliding coinciding with areas of peak rainfall rates, pointing toward climatic modulation of predominantly tectonically driven denudation rates.}, language = {en} } @misc{BernhardtMelnickHebbelnetal.2015, author = {Bernhardt, Anne and Melnick, Daniel and Hebbeln, Dierk and L{\"u}ckge, Andreas and Strecker, Manfred}, title = {Turbidite paleoseismology along the active continental margin of Chile - Feasible or not?}, series = {Quaternary science reviews : the international multidisciplinary research and review journal}, volume = {120}, journal = {Quaternary science reviews : the international multidisciplinary research and review journal}, publisher = {Elsevier}, address = {Oxford}, issn = {0277-3791}, doi = {10.1016/j.quascirev.2015.04.001}, pages = {71 -- 92}, year = {2015}, abstract = {Much progress has been made in estimating recurrence intervals of great and giant subduction earthquakes using terrestrial, lacustrine, and marine paleoseismic archives. Recent detailed records suggest these earthquakes may have variable recurrence periods and magnitudes forming supercycles. Understanding seismic supercycles requires long paleoseismic archives that record timing and magnitude of such events. Turbidite paleoseismic archives may potentially extend past earthquake records to the Pleistocene and can thus complement commonly shorter-term terrestrial archives. However, in order to unambiguously establish recurring seismicity as a trigger mechanism for turbidity currents, synchronous deposition of turbidites in widely spaced, isolated depocenters has to be ascertained. Furthermore, characteristics that predispose a seismically active continental margin to turbidite paleoseismology and the correct sample site selection have to be taken into account. Here we analyze 8 marine sediment cores along 950 km of the Chile margin to test for the feasibility of compiling detailed and continuous paleoseismic records based on turbidites. Our results suggest that the deposition of areally widespread, synchronous turbidites triggered by seismicity is largely controlled by sediment supply and, hence, the climatic and geomorphic conditions of the adjacent subaerial setting. The feasibility of compiling a turbidite paleoseismic record depends on the delicate balance between sufficient sediment supply providing material to fail frequently during seismic shaking and sufficiently low sedimentation rates to allow for coeval accumulation of planktonic foraminifera for high-resolution radiocarbon dating. We conclude that offshore northern central Chile (29-32.5 degrees S) Holocene turbidite paleoseismology is not feasible, because sediment supply from the semi-arid mainland is low and almost no Holocene turbidity-current deposits are found in the cores. In contrast, in the humid region between 36 and 38 degrees S frequent Holocene turbidite deposition may generally correspond to paleoseismic events. However, high terrigenous sedimentation rates prevent high-resolution radiocarbon dating. The climatic transition region between 32.5 and 36 degrees S appears to be best suited for turbidite paleoseismology. (C) 2015 Elsevier Ltd. All rights reserved.}, language = {en} } @phdthesis{Sauma2015, author = {Sauma, Natalia Zamora}, title = {Tsunami hazard analysis in Central America with emphasis on uncertainties}, school = {Universit{\"a}t Potsdam}, pages = {184}, year = {2015}, language = {en} } @article{SelleLangeLischeidetal.2015, author = {Selle, Benny and Lange, Holger and Lischeid, Gunnar and Hauhs, Michael}, title = {Transit times of water under steady stormflow conditions in the Gardsjon G1 catchment}, series = {Hydrological processes}, volume = {29}, journal = {Hydrological processes}, number = {22}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0885-6087}, doi = {10.1002/hyp.10528}, pages = {4657 -- 4665}, year = {2015}, abstract = {In this paper we report on a series of replicated tracer experiments with deuterium conducted under controlled, steady stormflow conditions at the Gardsjon G1 catchment in south-western Sweden. In five different years, these experiments were carried out in a subcatchment of G1. Deuterium was applied as a narrow pulse so that distributions of water transit times could be directly inferred from the observed tracer breakthrough curves. Significantly different transit times of water were observed under similar experimental conditions. Coefficients of variation for estimated mean transit times were greater than 60\%, which can be understood as a measure of the interannual variability for this type of experiments. Implications for water transit times under more natural flow conditions as wells as for future experimentation are discussed. Copyright (c) 2015 John Wiley \& Sons, Ltd.}, language = {en} } @article{MarcHoviusMeunieretal.2015, author = {Marc, Odin and Hovius, Niels and Meunier, Patrick and Uchida, Taro and Hayashi, Shin-Ichiro}, title = {Transient changes of landslide rates after earthquakes}, series = {Geology}, volume = {43}, journal = {Geology}, number = {10}, publisher = {American Institute of Physics}, address = {Boulder}, issn = {0091-7613}, doi = {10.1130/G36961.1}, pages = {883 -- 886}, year = {2015}, abstract = {Earthquakes impart an impressive force on epicentral landscapes, with immediate catastrophic hillslope response. However, their legacy on geomorphic process rates remains poorly constrained. We have determined the evolution of landslide rates in the epicentral areas of four intermediate to large earthquakes (M-w, 6.6-7.6). In each area, landsliding correlates with the cumulative precipitation during a given interval. Normalizing for this meteorological forcing, landslide rates have been found to peak after an earthquake and decay to background values in 1-4 yr, with the decay time scale probably proportional to the earthquake magnitude. The transient pulse of landsliding is not related to external forcing such as rainfall or aftershocks, and we tentatively attribute it to the reduction and subsequent recovery of ground strength. Observed geomorphic trends are not linked with groundwater level changes or root system damage, both of which could affect substrate strength. We propose that they are caused by reversible damage of rock mass and/or loosening of regolith. Qualitative accounts of ground cracking due to strong ground motion abound, and our observations are circumstantial evidence of its potential importance in setting landscape sensitivity to meteorological forcing after large earthquakes.}, language = {en} } @article{TronickeAllroggen2015, author = {Tronicke, Jens and Allroggen, Niklas}, title = {Toward automated delineation of ground-penetrating radar facies in clastic sediments: An example from stratified glaciofluvial deposits}, series = {Geophysics}, volume = {80}, journal = {Geophysics}, number = {4}, publisher = {Society of Exploration Geophysicists}, address = {Tulsa}, issn = {0016-8033}, doi = {10.1190/GEO2015-0188.1}, pages = {A89 -- A94}, year = {2015}, abstract = {Ground-penetrating radar (GPR) is an established geophysical method to explore near-surface sedimentary environments. Interpreting GPR images is largely based on manual procedures following concepts known as GPR facies analysis. We have developed a novel strategy to distinguish GPR facies in a largely automated and more objective manner. First, we calculate 13 textural attributes to quantify GPR reflection characteristics. Then, this database is reduced using principal component analysis. Finally, we image the dominating principal components using composite imaging and classify them using standard clustering methods. The potential of this work-flow is evaluated using a 2D GPR field example collected across stratified glaciofluvial deposits. Our results demonstrate that the derived facies images are well correlated with the composition and the porosity of the sediments as known from independent borehole logs. Our analysis strategy eases and improves the interpretability of GPR data and will help in a variety of geologic and hydrological problems.}, language = {en} } @article{AllroggenTronickeDelocketal.2015, author = {Allroggen, Niklas and Tronicke, Jens and Delock, Marcel and B{\"o}niger, Urs}, title = {Topographic migration of 2D and 3D ground-penetrating radar data considering variable velocities}, series = {Near surface geophysics}, volume = {13}, journal = {Near surface geophysics}, number = {3}, publisher = {European Association of Geoscientists \& Engineers}, address = {Houten}, issn = {1569-4445}, doi = {10.3997/1873-0604.2014037}, pages = {4}, year = {2015}, abstract = {We present a 2D/3D topographic migration scheme for ground-penetrating radar (GPR) data which is able to account for variable velocities by using the root mean square (rms) velocity approximation. We test our migration scheme using a synthetic 2D example and compare our migrated image to the results obtained using common GPR migration approaches. Furthermore, we apply it to 2D and 3D field data. These examples are recorded across common subsurface settings including surface topography and variations in the GPR subsurface velocity field caused by a shallow ground water table. In such field settings, our migration strategy provides well focused images of commonoffset GPR data without the need for a detailed interval velocity model. The synthetic and field examples demonstrate that our topographic migration scheme allows for accurate GPR imaging in the presence of variations in surface topography and subsurface velocity.}, language = {en} } @article{AyguelOkayOberhaenslietal.2015, author = {Ayg{\"u}l, Mesut and Okay, Aral I. and Oberh{\"a}nsli, Roland and Ziemann, Martin Andreas}, title = {Thermal structure of low-grade accreted Lower Cretaceous distal turbidites, the Central Pontides, Turkey: insights for tectonic thickening of an accretionary wedge}, series = {Turkish journal of earth sciences = T{\"u}rk yerbilimleri dergisi}, volume = {24}, journal = {Turkish journal of earth sciences = T{\"u}rk yerbilimleri dergisi}, number = {5}, publisher = {T{\"u}bitak}, address = {Ankara}, issn = {1300-0985}, doi = {10.3906/yer-1504-4}, pages = {461 -- 474}, year = {2015}, abstract = {Albian-Turonian subduction-accretionary complexes are exposed widely in the Central Pontides. A major portion of the accretionary complexes is made up of a metaflysch sequence consisting of slate/phyllite and metasandstone intercalation with blocks of marble, Na-amphibole bearing metabasite, and serpentinite. The metaflysch sequence represents distal parts of a large Lower Cretaceous submarine turbidite fan deposited on the Laurasian active continental margin that was subsequently accreted and metamorphosed during the Albian. Raman spectra of carbonaceous material of the metapelitic rocks revealed that the metaflysch consists of metamorphic packets with distinct peak metamorphic temperatures. The majority of the metapelites are low-temperature (ca. 330 degrees C) slates characterized by lack of differentiation of the graphite (G) and D2 defect bands. They possibly represent offscraped distal turbidites along the toe of the Albian accretionary wedge. Other phyllites are characterized by a slightly pronounced G band with a D2 defect band occurring on its shoulder. Peak metamorphic temperatures of these phyllites are constrained to 370-385 degrees C. The phyllites are associated with a strip of incipient blueschist facies metabasites and are found as a sliver within the offscraped distal turbidites. We interpret the phyllites as underplated continental sediments together with oceanic crustal basalt along the basal decollement. Tectonic emplacement of the underplated rocks into the offscraped distal turbidites was possibly achieved by out-of-sequence thrusting causing tectonic thickening and uplift of the wedge.}, language = {en} } @article{GhodsShabanianBergmanetal.2015, author = {Ghods, Abdolreza and Shabanian, Esmaeil and Bergman, Eric and Faridi, Mohammad and Donner, Stefanie and Mortezanejad, Gholamreza and Aziz-Zanjani, Asiyeh}, title = {The Varzaghan-Ahar, Iran, Earthquake Doublet (M-w 6.4, 6.2): implications for the geodynamics of northwest Iran}, series = {Geophysical journal international}, volume = {203}, journal = {Geophysical journal international}, number = {1}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {0956-540X}, doi = {10.1093/gji/ggv306}, pages = {522 -- 540}, year = {2015}, abstract = {On 2012 August 11, a pair of large, damaging earthquakes struck the Varzaghan-Ahar region in northwest Iran, in a region where there was no major mapped fault or any well-documented historical seismicity. To investigate the active tectonics of the source region we applied a combination of seismological methods (local aftershock network, calibrated multiple event relocation and focal mechanism studies), field observations (structural geology and geomorphological) and inversions for the regional stress field. The epicentral region is north of the North Tabriz Fault. The first main shock is characterized by right-lateral strike-slip motion on an almost E-W fault plane of about 23 km length extending from the surface to a depth of about 14 km. The second main shock occurred on an ENE-striking fault that dips at 60-70A degrees to the NW. Independent inversions of focal mechanisms and geologically determined fault kinematic data for the active stress state yield a transpressional tectonic regime with sigma(1) oriented N132E. For the region northeast of the North Tabriz Fault, the presence of rigid lithosphere of the South Caspian Basin implies the kinematic adjustment by northward transferring of the contracted masses through both distributed deformation and structural deflections. Our results suggest that the kinematic adjustment inside a contracting wedge may occur along interacting crosswise or conjugate faults to accommodate low rates of internal deformation. At a global scale, our results indicate that despite the basic assumption of 'rigid blocks' in geodetic plate modelling, internal deformation of block-like regions could control the kinematics of deformation and the level of seismic hazard within and around such regions of low deformation rate.}, language = {en} } @article{MenzelAnupamaBasavaiahetal.2015, author = {Menzel, Philip and Anupama, Krishnamurthy and Basavaiah, Nathani and Das, Brijraj Krishna and Gaye, Birgit and Herrmann, Nicole and Prasad, Sushma}, title = {The use of amino acid analyses in (palaeo-) limnological investigations: A comparative study of four Indian lakes in different climate regimes}, series = {Geochimica et cosmochimica acta : journal of the Geochemical Society and the Meteoritical Society}, volume = {160}, journal = {Geochimica et cosmochimica acta : journal of the Geochemical Society and the Meteoritical Society}, publisher = {Elsevier}, address = {Oxford}, issn = {0016-7037}, doi = {10.1016/j.gca.2015.03.028}, pages = {25 -- 37}, year = {2015}, abstract = {In the present study, we report the results of comprehensive amino acid (AA) analyses of four Indian lakes from different climate regimes. We focus on the investigation of sediment cores retrieved from the lakes but data of modern sediment as well as vascular plant, soil, and suspended particulate matter samples from individual lakes are also presented. Commonly used degradation and organic matter source indices are tested for their applicability to the lake sediments, and we discuss potential reasons for possible limitations. A principal component analysis including the monomeric AA composition of organic matter of all analysed samples indicates that differences in organic matter sources and the environmental properties of the individual lakes are responsible for the major variability in monomeric AA distribution of the different samples. However, the PCA also gives a factor that most probably separates the samples according to their state of organic matter degradation. Using the factor loadings of the individual AA monomers, we calculate a lake sediment degradation index (LI) that might be applicable to other palaeo-lake investigations. (C) 2015 Elsevier Ltd. All rights reserved.}, language = {en} } @phdthesis{Rohrmann2015, author = {Rohrmann, Alexander}, title = {The role of wind and water in shaping earth's plateaus}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-77938}, school = {Universit{\"a}t Potsdam}, pages = {XXV, 157}, year = {2015}, abstract = {The overarching goal of this dissertation is to provide a better understanding of the role of wind and water in shaping Earth's Cenozoic orogenic plateaus - prominent high-elevation, low relief sectors in the interior of Cenozoic mountain belts. In particular, the feedbacks between surface uplift, the build-up of topography and ensuing changes in precipitation, erosion, and vegetation patterns are addressed in light of past and future climate change. Regionally, the study focuses on the two world's largest plateaus, the Altiplano-Puna Plateau of the Andes and Tibetan Plateau, both characterized by average elevations of >4 km. Both plateaus feature high, deeply incised flanks with pronounced gradients in rainfall, vegetation, hydrology, and surface processes. These characteristics are rooted in the role of plateaus to act as efficient orographic barriers to rainfall and to force changes in atmospheric flow. The thesis examines the complex topics of tectonic and climatic forcing of the surface-process regime on three different spatial and temporal scales: (1) bedrock wind-erosion rates are quantified in the arid Qaidam Basin of NW Tibet over millennial timescales using cosmogenic radionuclide dating; (2) present-day stable isotope composition in rainfall is examined across the south-central Andes in three transects between 22° S and 28° S; these data are modeled and assessed with remotely sensed rainfall data of the Tropical Rainfall Measuring Mission and the Moderate Resolution Imaging Spectroradiometer; (3) finally, a 2.5-km-long Mio-Pliocene sedimentary record of the intermontane Angastaco Basin (25°45' S, 66°00' W) is presented in the context of hydrogen and carbon compositions of molecular lipid biomarker, and oxygen and carbon isotopes obtained from pedogenic carbonates; these records are compared to other environmental proxies, including hydrated volcanic glass shards from volcanic ashes intercalated in the sedimentary strata. There are few quantitative estimates of eolian bedrock-removal rates from arid, low relief landscapes. Wind-erosion rates from the western Qaidam Basin based on cosmogenic 10Be measurements document erosion rates between 0.05 to 0.4 mm/yr. This finding indicates that in arid environments with strong winds, hyperaridity, exposure of friable strata, and ongoing rock deformation and uplift, wind erosion can outpace fluvial erosion. Large eroded sediment volumes within the Qaidam Basin and coeval dust deposition on the Chinese Loess plateau, exemplify the importance of dust production within arid plateau environments for marine and terrestrial depositional processes, but also health issues and fertilization of soils. In the south-central Andes, the analysis of 234 stream-water samples for oxygen and hydrogen reveals that areas experiencing deep convective storms do not show the commonly observed patterns of isotopic fractionation and the expected co-varying relationships between oxygen and hydrogen with increasing elevation. These convective storms are formed over semi-arid intermontane basins in the transition between the broken foreland of the Sierras Pampeanas, the Eastern Cordillera, and the Puna Plateau in the interior of the orogen. Here, convective rainfall dominates the precipitation budget and no systematic stable isotope-elevation relationship exists. Regions to the north, in the transition between the broken foreland and the Subandean foreland fold-and-thrust belt, the impact of convection is subdued, with lower degrees of storminess and a stronger expected isotope-elevation relationship. This finding of present-day fractionation trends of meteoric water is of great importance for paleoenvironmental studies in attempts to use stable isotope relationships in the reconstruction of paleoelevations. The third part of the thesis focuses on the paleohydrological characteristics of the Mio-Pliocene (10-2 Ma) Angastaco Basin sedimentary record, which reveals far-reaching environmental changes during Andean uplift and orographic barrier formation. A precipitation- evapotranspiration record identifies the onset of a precipitation regime related to the South American Low Level Jet at this latitude after 9 Ma. Humid foreland conditions existed until 7 Ma, followed by orographic barrier uplift to the east of the present-day Angastaco Basin. This was superseded by rapid (~0.5 Myr) aridification in an intermontane basin, highlighting the effects of eastward-directed deformation. A transition in vegetation cover from a humid C3 forest ecosystem to semi-arid C4-dominated vegetation was coeval with continued basin uplift to modern elevations.}, language = {en} } @article{PuppeEhrmannKaczoreketal.2015, author = {Puppe, Daniel and Ehrmann, Otto and Kaczorek, Danuta and Wanner, Manfred and Sommer, Michael}, title = {The protozoic Si pool in temperate forest ecosystems - Quantification, abiotic controls and interactions with earthworms}, series = {Geoderma : an international journal of soil science}, volume = {243}, journal = {Geoderma : an international journal of soil science}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0016-7061}, doi = {10.1016/j.geoderma.2014.12.018}, pages = {196 -- 204}, year = {2015}, abstract = {Biogenic silicon (BSI) pools influence Si cycling in terrestrial ecosystems. As research has been focused mainly on phytogenic BSi pools until now, there is only little information available on quantities of other BSi pools. There are no systematic studies on protozoic Si pools - here represented by idiosomic testate amoebae (TA) - and abiotic and biotic influences in temperate forest ecosystems. We selected ten old forests along a strong gradient in soil forming factors (especially parent material and climate), soil properties and humus forms. We quantified idiosomic Si pools, corresponding annual biosilicification, plant-available and amorphous Si fractions of topsoil horizons. Furthermore, we analyzed the potential influences of abiotic factors (e.g. soil pH) and earthworms on idiosomic Si pools. While idiosomic Si pools were relatively small (up to 5 kg Si ha(-1)), annual biosilicification rates of living TA (17-80 kg Si ha(-1)) were comparable to or even exceeded reported data of annual Si uptake by trees. Soil pH exerted a strong, non-linear control on plant-available Si. Surprisingly, no relationship between Si supply and idiosomic Si pools could be found (no Si limitation). Instead, idiosomic Si pools showed a strong, negative relationship to earthworm biomasses, which corresponded to humus forms. We concluded that earthworms control idiosomic Si pools in forest soils by direct (feeding, competition) and/or indirect mechanisms (e.g. change of habitat structure). Earthworms themselves were strongly influenced by soil pH: Below a threshold of pH 3.8 no endogeic or anecic earthworms existed. As soil pH is a result of weathering and acidification idiosomic Si pools are indirectly, but ultimately controlled by soil forming factors, mainly parent material and climate. (C) 2014 Elsevier B.V. All rights reserved.}, language = {en} } @article{EgholmAndersenKnudsenetal.2015, author = {Egholm, D. L. and Andersen, Jane Lund and Knudsen, M. F. and Jansen, John D. and Nielsen, S. B.}, title = {The periglacial engine of mountain erosion - Part 2: Modelling large-scale landscape evolution}, series = {Earth surface dynamics}, volume = {3}, journal = {Earth surface dynamics}, number = {4}, publisher = {Copernicus}, address = {G{\"o}ttingen}, issn = {2196-6311}, doi = {10.5194/esurf-3-463-2015}, pages = {463 -- 482}, year = {2015}, abstract = {There is growing recognition of strong periglacial control on bedrock erosion in mountain landscapes, including the shaping of low-relief surfaces at high elevations (summit flats). But, as yet, the hypothesis that frost action was crucial to the assumed Late Cenozoic rise in erosion rates remains compelling and untested. Here we present a landscape evolution model incorporating two key periglacial processes - regolith production via frost cracking and sediment transport via frost creep - which together are harnessed to variations in temperature and the evolving thickness of sediment cover. Our computational experiments time-integrate the contribution of frost action to shaping mountain topography over million-year timescales, with the primary and highly reproducible outcome being the development of flattish or gently convex summit flats. A simple scaling of temperature to marine delta O-18 records spanning the past 14 Myr indicates that the highest summit flats in mid-to high-latitude mountains may have formed via frost action prior to the Quaternary. We suggest that deep cooling in the Quaternary accelerated mechanical weathering globally by significantly expanding the area subject to frost. Further, the inclusion of subglacial erosion alongside periglacial processes in our computational experiments points to alpine glaciers increasing the long-term efficiency of frost-driven erosion by steepening hillslopes.}, language = {en} } @article{AndersenEgholmKnudsenetal.2015, author = {Andersen, Jane Lund and Egholm, D. L. and Knudsen, M. F. and Jansen, John D. and Nielsen, S. B.}, title = {The periglacial engine of mountain erosion - Part 1: Rates of frost cracking and frost creep}, series = {Earth surface dynamics}, volume = {3}, journal = {Earth surface dynamics}, number = {4}, publisher = {Copernicus}, address = {G{\"o}ttingen}, issn = {2196-6311}, doi = {10.5194/esurf-3-447-2015}, pages = {447 -- 462}, year = {2015}, abstract = {With accelerating climate cooling in the late Cenozoic, glacial and periglacial erosion became more widespread on the surface of the Earth. The resultant shift in erosion patterns significantly changed the large-scale morphology of many mountain ranges worldwide. Whereas the glacial fingerprint is easily distinguished by its characteristic fjords and U-shaped valleys, the periglacial fingerprint is more subtle but potentially prevails in some mid- to high-latitude landscapes. Previous models have advocated a frost-driven control on debris production at steep headwalls and glacial valley sides. Here we investigate the important role that periglacial processes also play in less steep parts of mountain landscapes. Understanding the influences of frost-driven processes in low-relief areas requires a focus on the consequences of an accreting soil mantle, which characterises such surfaces. We present a new model that quantifies two key physical processes: frost cracking and frost creep, as a function of both temperature and sediment thickness. Our results yield new insights into how climate and sediment transport properties combine to scale the intensity of periglacial processes. The thickness of the soil mantle strongly modulates the relation between climate and the intensity of mechanical weathering and sediment flux. Our results also point to an offset between the conditions that promote frost cracking and those that promote frost creep, indicating that a stable climate can provide optimal conditions for only one of those processes at a time. Finally, quantifying these relations also opens up the possibility of including periglacial processes in large-scale, long-term landscape evolution models, as demonstrated in a companion paper.}, language = {en} } @article{KalbeMischkeDulskietal.2015, author = {Kalbe, Johannes and Mischke, Steffen and Dulski, Peter and Sharon, Gonen}, title = {The Middle Palaeolithic Nahal Mahanayeem Outlet site, Israel: reconstructing the environment of Late Pleistocene wetlands in the eastern Mediterranean from ostracods}, series = {Journal of archaeological science}, volume = {54}, journal = {Journal of archaeological science}, publisher = {Elsevier}, address = {London}, issn = {0305-4403}, doi = {10.1016/j.jas.2014.04.018}, pages = {385 -- 395}, year = {2015}, abstract = {We present ostracod data from the Middle Palaeolithic open air site of Nahal Mahanayeem Outlet (NMO) at the southern edge of the Hula Basin, northern Israel. Sediments of two Pleistocene water bodies are exposed at the site. The first one is an archaeologically sterile, light-colored limnic carbonate with an Early Pleistocene age. It contains an ostracod fauna assemblage dominated by Candona neglecta, Candonopsis kingsleii, and Pseudocandona sp., and, in minor abundances, Cypria ophtalmica, Cyprideis sp., Humphcypris sp., Fabaeformiscandona cf. fabaeformis and Ilyocypris sp. These sediments were deposited in a shallow, freshwater to oligohaline lake under stable conditions. Sediments of the second water body are silty and dark-colored with a depositional age of 65 ka, belonging to the Late Pleistocene Ashmura Formation. The unit covers a geologically complex topography of tectonically uplifted limnic deposits and a hill-like gravel bar at the site. The most important archaeological layer is situated at its base, containing a lithic assemblage ascribed primarily to the Middle Palaeolithic Mousterian tradition and very well preserved flora and fauna. In the sediments from the archaeological layers, the brackish water ostracod Cyprideis torosa and the foraminifer Ammonia tepida could be identified. In sediments of the Ashmura Formation taken near the site, C. neglecta, Candona angulata, Ilyogpris sp., C kingsleii, Pseudocandona sp., C ophtalmica, Darwinula stevensoni, Trajancypris sp. and Potamogpris smaragdina were found, indicating a freshwater to slightly oligohaline stagnant water body. The ostracod fauna of the NMO site, together with geochemical data, allow us to reconstruct a depositional environment of the margin at a shallow lake with brackish or saline springs nearby during the site's occupation by Middle Palaeolithic humans. Additionally, Candona weltneri, Candona cf. meerfeldiana, C kingsleii, Cyclocypris laevis, C ophtalmica, Cyprideis sp., Fabaeformiscandona cf. fabaeformis, P. smaragdina, Pseudocandona depressa, Trajancypris sp, Zonocypris cf. costata and A. tepida could be recorded for the first time for the Pleistocene limnic strata of the Hula Basin. (C) 2014 Elsevier Ltd. All rights reserved.}, language = {en} } @article{BallatoLandgrafSchildgenetal.2015, author = {Ballato, Paolo and Landgraf, Angela and Schildgen, Taylor F. and Stockli, Daniel F. and Fox, Matthew and Ghassemi, Mohammad R. and Kirby, Eric and Strecker, Manfred}, title = {The growth of a mountain belt forced by base-level fall: Tectonics and surface processes during the evolution of the Alborz Mountains, N Iran}, series = {Earth \& planetary science letters}, volume = {425}, journal = {Earth \& planetary science letters}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0012-821X}, doi = {10.1016/j.epsl.2015.05.051}, pages = {204 -- 218}, year = {2015}, abstract = {The idea that climatically modulated erosion may impact orogenic processes has challenged geoscientists for decades. Although modeling studies and physical calculations have provided a solid theoretical basis supporting this interaction, to date, field-based work has produced inconclusive results. The central-western Alborz Mountains in the northern sectors of the Arabia-Eurasia collision zone constitute a promising area to explore these potential feedbacks. This region is characterized by asymmetric precipitation superimposed on an orogen with a history of spatiotemporal changes in exhumation rates, deformation patterns, and prolonged, km-scale base-level changes. Our analysis suggests that despite the existence of a strong climatic gradient at least since 17.5 Ma, the early orogenic evolution (from similar to 36 to 9-6 Ma) was characterized by decoupled orographic precipitation and tectonics. In particular, faster exhumation and sedimentation along the more arid southern orogenic flank point to a north-directed accretionary flux and underthrusting of Central Iran. Conversely, from 6 to 3 Ma, erosion rates along the northern orogenic flank became higher than those in the south, where they dropped to minimum values. This change occurred during a similar to 3-Myr-long, km-scale base-level lowering event in the Caspian Sea. We speculate that mass redistribution processes along the northern flank of the Alborz and presumably across all mountain belts adjacent to the South Caspian Basin and more stable areas of the Eurasian plate increased the sediment load in the basin and ultimately led to the underthrusting of the Caspian Basin beneath the Alborz Mountains. This underthrusting in turn triggered a new phase of northward orogenic expansion, transformed the wetter northern flank into a new pro-wedge, and led to the establishment of apparent steady-state conditions along the northern orogenic flank (i.e., rock uplift equal to erosion rates). Conversely, the southern mountain front became the retro-wedge and experienced limited tectonic activity. These observations overall raise the possibility that mass-distribution processes during a pronounced erosion phase driven by base-level changes may have contributed to the inferred regional plate-tectonic reorganization of the northern Arabia-Eurasia collision during the last similar to 5 Ma. (C) 2015 Elsevier B.V. All rights reserved.}, language = {en} } @article{DallmeyerClaussenFischeretal.2015, author = {Dallmeyer, A. and Claussen, M. and Fischer, N. and Haberkorn, K. and Wagner, S. and Pfeiffer, M. and Jin, L. and Khon, V. and Wang, Y. and Herzschuh, Ulrike}, title = {The evolution of sub-monsoon systems in the Afro-Asian monsoon region during the Holocene - comparison of different transient climate model simulations}, series = {Climate of the past : an interactive open access journal of the European Geosciences Union}, volume = {11}, journal = {Climate of the past : an interactive open access journal of the European Geosciences Union}, number = {2}, publisher = {Copernicus}, address = {G{\"o}ttingen}, issn = {1814-9324}, doi = {10.5194/cp-11-305-2015}, pages = {305 -- 326}, year = {2015}, abstract = {The recently proposed global monsoon hypothesis interprets monsoon systems as part of one global-scale atmospheric overturning circulation, implying a connection between the regional monsoon systems and an in-phase behaviour of all northern hemispheric monsoons on annual timescales (Trenberth et al., 2000). Whether this concept can be applied to past climates and variability on longer timescales is still under debate, because the monsoon systems exhibit different regional characteristics such as different seasonality (i. e. onset, peak and withdrawal). To investigate the interconnection of different monsoon systems during the pre-industrial Holocene, five transient global climate model simulations have been analysed with respect to the rainfall trend and variability in different sub-domains of the Afro-Asian monsoon region. Our analysis suggests that on millennial timescales with varying orbital forcing, the monsoons do not behave as a tightly connected global system. According to the models, the Indian and North African monsoons are coupled, showing similar rainfall trend and moderate correlation in centennial rainfall variability in all models. The East Asian monsoon changes independently during the Holocene. The dissimilarities in the seasonality of the monsoon sub-systems lead to a stronger response of the North African and Indian monsoon systems to the Holocene insolation forcing than of the East Asian monsoon and affect the seasonal distribution of Holocene rainfall variations. Within the Indian and North African monsoon domain, precipitation solely changes during the summer months, showing a decreasing Holocene precipitation trend. In the East Asian monsoon region, the precipitation signal is determined by an increasing precipitation trend during spring and a decreasing precipitation change during summer, partly balancing each other. A synthesis of reconstructions and the model results do not reveal an impact of the different seasonality on the timing of the Holocene rainfall optimum in the different sub-monsoon systems. Rather they indicate locally inhomogeneous rainfall changes and show that single palaeo-records should not be used to characterise the rainfall change and monsoon evolution for entire monsoon sub-systems.}, language = {en} } @article{HeistermannCollisDixonetal.2015, author = {Heistermann, Maik and Collis, Scott and Dixon, M. J. and Giangrande, S. and Helmus, J. J. and Kelley, B. and Koistinen, J. and Michelson, D. B. and Peura, M. and Pfaff, T. and Wolff, D. B.}, title = {The emergence of open-source software for the weather radar community}, series = {Bulletin of the American Meteorological Society}, volume = {96}, journal = {Bulletin of the American Meteorological Society}, number = {1}, publisher = {American Meteorological Soc.}, address = {Boston}, issn = {0003-0007}, doi = {10.1175/BAMS-D-13-00240.1}, pages = {117 -- +}, year = {2015}, abstract = {Weather radar analysis has become increasingly sophisticated over the past 50 years, and efforts to keep software up to date have generally lagged behind the needs of the users. We argue that progress has been impeded by the fact that software has not been developed and shared as a community. Recently, the situation has been changing. In this paper, the developers of a number of open-source software (OSS) projects highlight the potential of OSS to advance radar-related research. We argue that the community-based development of OSS holds the potential to reduce duplication of efforts and to create transparency in implemented algorithms while improving the quality and scope of the software. We also conclude that there is sufficiently mature technology to support collaboration across different software projects. This could allow for consolidation toward a set of interoperable software platforms, each designed to accommodate very specific user requirements.}, language = {en} } @phdthesis{Mueller2015, author = {M{\"u}ller, Eva Nora}, title = {The ecohydrological transfers, interactions and degradation arising from high-intensity storm events}, school = {Universit{\"a}t Potsdam}, pages = {224}, year = {2015}, language = {en} } @phdthesis{Hunke2015, author = {Hunke, Philip Paul}, title = {The Brazilian Cerrado: ecohydrological assessment of water and soil degradation in heavily modified meso-scale catchments}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-85110}, school = {Universit{\"a}t Potsdam}, pages = {xi, 124}, year = {2015}, abstract = {The Brazilian Cerrado is recognised as one of the most threatened biomes in the world, as the region has experienced a striking change from natural vegetation to intense cash crop production. The impacts of rapid agricultural expansion on soil and water resources are still poorly understood in the region. Therefore, the overall aim of the thesis is to improve our understanding of the ecohydrological processes causing water and soil degradation in the Brazilian Cerrado. I first present a metaanalysis to provide quantitative evidence and identifying the main impacts of soil and water alterations resulting from land use change. Second, field studies were conducted to (i) examine the effects of land use change on soils of natural cerrado transformed to common croplands and pasture and (ii) indicate how agricultural production affects water quality across a meso-scale catchment. Third, the ecohydrological process-based model SWAT was tested with simple scenario analyses to gain insight into the impacts of land use and climate change on the water cycling in the upper S{\~a}o Louren{\c{c}}o catchment which experienced decreasing discharges in the last 40 years. Soil and water quality parameters from different land uses were extracted from 89 soil and 18 water studies in different regions across the Cerrado. Significant effects on pH, bulk density and available P and K for croplands and less-pronounced effects on pastures were evident. Soil total N did not differ between land uses because most of the cropland sites were N-fixing soybean cultivations, which are not artificially fertilized with N. By contrast, water quality studies showed N enrichment in agricultural catchments, indicating fertilizer impacts and potential susceptibility to eutrophication. Regardless of the land use, P is widely absent because of the high-fixing capacities of deeply weathered soils and the filtering capacity of riparian vegetation. Pesticides, however, were consistently detected throughout the entire aquatic system. In several case studies, extremely high-peak concentrations exceeded Brazilian and EU water quality limits, which pose serious health risks. My field study revealed that land conversion caused a significant reduction in infiltration rates near the soil surface of pasture (-96 \%) and croplands (-90 \% to -93 \%). Soil aggregate stability was significantly reduced in croplands than in cerrado and pasture. Soybean crops had extremely high extractable P (80 mg kg-1), whereas pasture N levels declined. A snapshot water sampling showed strong seasonality in water quality parameters. Higher temperature, oxi-reduction potential (ORP), NO2-, and very low oxygen concentrations (<5 mg•l-1) and saturation (<60 \%) were recorded during the rainy season. By contrast, remarkably high PO43- concentrations (up to 0.8 mg•l-1) were measured during the dry season. Water quality parameters were affected by agricultural activities at all sampled sub-catchments across the catchment, regardless of stream characteristic. Direct NO3- leaching appeared to play a minor role; however, water quality is affected by topsoil fertiliser inputs with impact on small low order streams and larger rivers. Land conversion leaving cropland soils more susceptible to surface erosion by increased overland flow events. In a third study, the field data were used to parameterise SWAT. The model was tested with different input data and calibrated in SWAT-CUP using the SUFI-2 algorithm. The model was judged reliable to simulate the water balance in the Cerrado. A complete cerrado, pasture and cropland cover was used to analyse the impact of land use on water cycling as well as climate change projections (2039-2058) according to the projections of the RCP 8.5 scenario. The actual evapotranspiration (ET) for the cropland scenario was higher compared to the cerrado cover (+100 mm a-1). Land use change scenarios confirmed that deforestation caused higher annual ET rates explaining partly the trend of decreased streamflow. Taking all climate change scenarios into account, the most likely effect is a prolongation of the dry season (by about one month), with higher peak flows in the rainy season. Consequently, potential threats for crop production with lower soil moisture and increased erosion and sediment transport during the rainy season are likely and should be considered in adaption plans. From the three studies of the thesis I conclude that land use intensification is likely to seriously limit the Cerrado's future regarding both agricultural productivity and ecosystem stability. Because only limited data are available for the vast biome, we recommend further field studies to understand the interaction between terrestrial and aquatic systems. This thesis may serve as a valuable database for integrated modelling to investigate the impact of land use and climate change on soil and water resources and to test and develop mitigation measures for the Cerrado in the future.}, language = {en} } @article{HunkeMuellerSchroederEsselbachetal.2015, author = {Hunke, Philip and M{\"u}ller, Eva Nora and Schr{\"o}der-Esselbach, Boris and Zeilhofer, Peter}, title = {The Brazilian Cerrado: assessment of water and soil degradation in catchments under intensive agricultural use}, series = {Ecohydrology : ecosystems, land and water process interactions, ecohydrogeomorphology}, volume = {8}, journal = {Ecohydrology : ecosystems, land and water process interactions, ecohydrogeomorphology}, number = {6}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {1936-0584}, doi = {10.1002/eco.1573}, pages = {1154 -- 1180}, year = {2015}, abstract = {The Brazilian Cerrado is recognized as one of the most threatened biomes in the world, as the region has experienced a striking change from natural Cerrado vegetation to intense cash crop production. This paper reviews the history of land conversion in the Cerrado and the development of soil properties and water resources under past and ongoing land use. We compared soil and water quality parameters from different land uses considering 80 soil and 18 water studies conducted in different regions across the Cerrado to provide quantitative evidence of soil and water alterations from land use change. Following the conversion of native Cerrado, significant effects on soil pH, bulk density and available P and K for croplands and less-pronounced effects on pastures were evident. Soil total N did not differ between land uses because most of the sites classified as croplands were nitrogen-fixing soybeans, which are not artificially fertilized with N. In contrast, water quality studies showed nitrogen enrichment in agricultural catchments, indicating fertilizer impacts and potential susceptibility to eutrophication. Regardless of the land use, P is widely absent because of the high-fixing capacities of deeply weathered soils and the filtering capacity of riparian vegetation. Pesticides, however, were consistently detected throughout the entire aquatic system. In several case studies, extremely high-peak concentrations exceeded Brazilian and European Union (EU) water quality limits, which were potentially accompanied by serious health implications. Land use intensification is likely to continue, particularly in regions where less annual rainfall and severe droughts are projected in the northeastern and western Cerrado. Thus, the leaching risk and displacement of agrochemicals are expected to increase, particularly because the current legislation has caused a reduction in riparian vegetation. We conclude that land use intensification is likely to seriously limit the Cerrado's future regarding both agricultural productivity and ecosystem stability. Because only limited data are available, we recommend further field studies to understand the interaction between terrestrial and aquatic systems. This study may serve as a valuable database for integrated modelling to investigate the impact of land use and climate change on soil and water resources and to test and develop mitigation measures for the Cerrado. Copyright (C) 2014 John Wiley \& Sons, Ltd.}, language = {en} } @article{DonnerGhodsKrueeretal.2015, author = {Donner, Stefanie and Ghods, Abdolreza and Kr{\"u}er, Frank and R{\"o}ßler, Dirk and Landgraf, Angela and Ballato, Paolo}, title = {The Ahar-Varzeghan Earthquake Doublet (M-w 6.4 and 6.2) of 11 August 2012: Regional Seismic Moment Tensors}, series = {Bulletin of the Seismological Society of America}, volume = {105}, journal = {Bulletin of the Seismological Society of America}, number = {2A}, publisher = {Seismological Society of America}, address = {Albany}, issn = {0037-1106}, doi = {10.1785/0120140042}, pages = {791 -- 807}, year = {2015}, abstract = {On 11 August 2012 an earthquake doublet (M-w 6.4 and 6.2) occurred near the city of Ahar, northwest Iran. Both events were only 6 km and 11 minutes apart, producing a surface rupture of about 12 km in length. Historical and modern seismicity has so far been sparse in this area. Spatially, the region represents a transitional zone between different tectonic domains, including compression in Iran, westward extrusion of the Anatolian plate, and thrusting beneath the Caucasus. In this study, we inverted the surface waveforms of the two mainshocks and 11 aftershocks (M-w >= 4.3) to obtain regional seismic moment tensors. The earthquakes analyzed can be grouped into pure strike slip (including the first mainshock) and oblique reverse mechanisms (including the second mainshock). The sequence provides information about faulting mechanisms at the spatial scale of the entire rock volume affected by the earthquake doublet, including coinciding deformation on minor faults (sub) parallel to the main fault and Riedel shears. It occurred on a so far unknown fault structure, which we call the Ahar fault. Alongside the seismological data, we used geological maps, satellite images, and digital elevation data to analyze the geomorphology of the region. Our analysis suggests that the adjacent North Tabriz fault, which accomodates up to 7 mm/yr of right-lateral strike-slip faulting, does not compensate the entire lateral shear strain, and that part of it is compensated farther north. Combined, our results suggest a temporally and spatially complex style of deformation (reverse and strike slip) overprinting older reverse deformation.}, language = {en} } @article{delFresnoDominguezCerdenaCescaetal.2015, author = {del Fresno, Carmen and Dominguez Cerdena, Itahiza and Cesca, Simone and Buforn, Elisa}, title = {The 8 October 2011 Earthquake at El Hierro (M-w 4.0): Focal Mechanisms of the Mainshock and Its Foreshocks}, series = {Bulletin of the Seismological Society of America}, volume = {105}, journal = {Bulletin of the Seismological Society of America}, number = {1}, publisher = {Seismological Society of America}, address = {Albany}, issn = {0037-1106}, doi = {10.1785/0120140151}, pages = {330 -- 340}, year = {2015}, abstract = {We have studied the focal mechanism of an M-w 4.0 earthquake that occurred on 8 October 2011 in the southwest of El Hierro (Canary Islands), the largest shock of the swarm that preceded the submarine eruption of El Hierro 2011-2012. The joint focal mechanism solution of 34 foreshocks has also been obtained. The results for the mainshock are consistent with a pure double-couple mechanism of a strike-slip motion with a reverse component and a focal depth of 12-13 km. The stress pattern obtained from the focal mechanism indicates horizontal compression in a north-northwest-south-southeast direction, parallel to the southern ridge of the island, and a quasi-horizontal extension in an east-west direction. Similar stress pattern is derived from the joint solution of the foreshocks. The occurrence of this family of earthquakes at the moment of the maximum strain rate of the pre-eruptive swarm suggests that their rupture process is related to tectonic stress, which led to the eruption only two days later, 5 km away from the mainshock epicenter.}, language = {en} } @article{WannerElmerSommeretal.2015, author = {Wanner, Manfred and Elmer, Michael and Sommer, Michael and Funk, Roger and Puppe, Daniel}, title = {Testate amoebae colonizing a newly exposed land surface are of airborne origin}, series = {Ecological indicators : integrating monitoring, assessment and management}, volume = {48}, journal = {Ecological indicators : integrating monitoring, assessment and management}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1470-160X}, doi = {10.1016/j.ecolind.2014.07.037}, pages = {55 -- 62}, year = {2015}, abstract = {We hypothesized that at the very beginning of terrestrial ecosystem development, airborne testate amoebae play a pivotal role in facilitating organismic colonization and related soil processes. We, therefore, analyzed size and quantity of airborne testate amoebae and immigration and colonization success of airborne testate amoebae on a new land surface (experimental site "Chicken Creek", artificial post-mining water catchment). Within an altogether 91-day exposure of 70 adhesive traps, 12 species of testate amoebae were identified to be of airborne origin. Phryganella acropodia (51\% of all individuals found, diameter about 35-45 mu m) and Centropyxis sphagnicola (23\% of all individuals found, longest axis about 55-68 mu m), occurred most frequently in the adhesive traps. We extrapolated an aerial amoeba deposition of 61 individuals d(-1) m(-2) (living and dead individuals combined). Although it would be necessary to have a longer sequence (some additional years), our analysis of the "target substrate" of aerial immigration (catchment site) may point to a shift from a stochastic (variable) beginning of community assembly to a more deterministic (stable) course. This shift was assigned to an age of seven years of initial soil development. Although experienced specialists are necessary to conduct these time-consuming studies, the presented data suggest that terrestrial amoebae are suitable indicators for initial ecosystem development and utilization.}, language = {en} } @masterthesis{Seyberth2015, type = {Bachelor Thesis}, author = {Seyberth, Karl}, title = {Test einer neuen Methode zur Synthetisierung hydrathaltiger Sedimentproben und Charakterisierung des Hydrathabitus anhand seismischer Messungen}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-81247}, school = {Universit{\"a}t Potsdam}, pages = {II, 41}, year = {2015}, abstract = {Methanhydrate sind besonders in Verbindung mit den steigenden Weltmarktpreisen f{\"u}r {\"O}l und Gas in den vergangenen Jahren mehr und mehr in den Fokus der Energiewirtschaft geraten, was zu einer starken Zunahme der angewandten Forschungsprojekte auf diesem Gebiet f{\"u}hrte. Da Methanhydrat nur unter hohem Druck und niedrigen Temperaturen stabil ist, ist die Gewinnung nat{\"u}rlicher Proben f{\"u}r Laboruntersuchungen technisch sehr aufwendig und vor allem teuer. Zur Charakterisierung der Eigenschaften hydratf{\"u}hrender Reservoire ist man h{\"a}ufig auf die Herstellung synthetischer Proben angewiesen. Die Eigenschaften der synthetisierten Proben sind dabei abh{\"a}ngig von der Herstellungsmethode und man ist noch immer auf der Suche nach Verfahren, mit denen sich m{\"o}glichst „naturnahe" Proben mit vertretbarem Aufwand erzeugen lassen. In der vorliegenden Arbeit wurde eine neue, relativ schnell durchf{\"u}hrbare Methode getestet, die im Porenraum von Sedimenten schwimmende bzw. gef{\"u}gest{\"u}tzende Hydrate bildet, wie sie in der Natur vorkommen. Gleichzeitig erzeugt sie eine gleichm{\"a}ßige Verteilung des Hydrats {\"u}ber die Probe und bietet gute Kontrolle {\"u}ber den Hydratgehalt. Sie funktioniert wie folgt: Eine mit einer KCl-L{\"o}sung ges{\"a}ttigte Sedimentprobe wird zu einem bestimmten Teil ausgefroren und das {\"u}brige Wasser mit Methan verdr{\"a}ngt. Durch Anlegen eines Methandrucks im Stabilit{\"a}tsbereich wird das Eis zu Methanhydrat umgesetzt. Im Anschluss wird die Probe erneut mit einer KCl-L{\"o}sung ges{\"a}ttigt. Anhand seismischer Messungen konnte best{\"a}tigt werden, dass Hydrat mit dem gew{\"u}nschten Hydrathabitus erzeugt wurde. Des Weiteren wurde gezeigt, dass die eishaltigen Proben aufgrund {\"a}hnlicher physikalischer Eigenschaften bereits vor der Umsetzung des Eises zu Methanhydrat als N{\"a}herung f{\"u}r Proben mit Porenraumhydrat verwendet werden k{\"o}nnen.}, language = {de} } @article{FahleHohenbrinkDietrichetal.2015, author = {Fahle, Marcus and Hohenbrink, Tobias Ludwig and Dietrich, Ottfried and Lischeid, Gunnar}, title = {Temporal variability of the optimal monitoring setup assessed using information theory}, series = {Water resources research}, volume = {51}, journal = {Water resources research}, number = {9}, publisher = {American Geophysical Union}, address = {Washington}, issn = {0043-1397}, doi = {10.1002/2015WR017137}, pages = {7723 -- 7743}, year = {2015}, abstract = {Hydrology is rich in methods that use information theory to evaluate monitoring networks. Yet in most existing studies, only the available data set as a whole is used, which neglects the intraannual variability of the hydrological system. In this paper, we demonstrate how this variability can be considered by extending monitoring evaluation to subsets of the available data. Therefore, we separately evaluated time windows of fixed length, which were shifted through the data set, and successively extended time windows. We used basic information theory measures and a greedy ranking algorithm based on the criterion of maximum information/minimum redundancy. The network investigated monitored surface and groundwater levels at quarter-hourly intervals and was located at an artificially drained lowland site in the Spreewald region in north-east Germany. The results revealed that some of the monitoring stations were of value permanently while others were needed only temporally. The prevailing meteorological conditions, particularly the amount of precipitation, affected the degree of similarity between the water levels measured. The hydrological system tended to act more individually during periods of no or little rainfall. The optimal monitoring setup, its stability, and the monitoring effort necessary were influenced by the meteorological forcing. Altogether, the methodology presented can help achieve a monitoring network design that has a more even performance or covers the conditions of interest (e.g., floods or droughts) best.}, language = {en} } @article{CifelliBallatoAlimohammadianetal.2015, author = {Cifelli, Francesca and Ballato, Paolo and Alimohammadian, Habib and Sabouri, Jafar and Mattei, Massimo}, title = {Tectonic magnetic lineation and oroclinal bending of the Alborz range: Implications on the Iran-Southern Caspian geodynamics}, series = {Tectonics}, volume = {34}, journal = {Tectonics}, number = {1}, publisher = {American Geophysical Union}, address = {Washington}, issn = {0278-7407}, doi = {10.1002/2014TC003626}, pages = {116 -- 132}, year = {2015}, abstract = {In this study we use the anisotropy of magnetic susceptibility (AMS) and paleomagnetic data for deciphering the origin of magnetic lineation in weakly deformed sedimentary rocks and for evaluating oroclinal processes within the Arabia-Eurasia collision zone. In particular, we have analyzed the Miocene Upper Red Formation (URF) from the outer curved front of the southern Central Alborz Mountains of north Iran, to test for the first time with paleomagnetic data the origin (primary versus secondary) of this orogenic arc. AMS data document the existence of a magnetic lineation parallel to the orientation of the major tectonic structures, which vary along strike from WNW to ENE. These directions are highly oblique to the paleoflow directions and hence suggest that the magnetic lineation in the URF was produced by compressional deformation during layer-parallel shortening. In addition, our paleomagnetic data document clockwise and anticlockwise rotations along vertical axis for the western and eastern sectors of the Central Alborz Mountains, respectively. Combined, our results suggest that the orogen represents an orocline, which formed not earlier than circa 7.6Ma most likely through bending processes caused by the relative motion between the rigid crustal blocks of the collision zone. Moreover, our study provides new insights into the Iran-Southern Caspian Basin kinematic evolution suggesting that the present-day SW motion of the South Caspian Basin with respect to Central Iran postdates oroclinal bending and hence cannot be as old as late Miocene to early Pliocene but a rather recent configuration (i.e., 3 to <1Ma).}, language = {en} } @article{KoberZeilingerHippeetal.2015, author = {Kober, Florian and Zeilinger, Gerold and Hippe, Kristina and Marc, Odin and Lendzioch, Theodora and Grischott, Reto and Christl, Marcus and Kubik, Peter W. and Zola, Ramiro}, title = {Tectonic and lithological controls on denudation rates in the central Bolivian Andes}, series = {Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth}, volume = {657}, journal = {Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0040-1951}, doi = {10.1016/j.tecto.2015.06.037}, pages = {230 -- 244}, year = {2015}, abstract = {The topographic signature of a mountain belt depends on the interplay of tectonic, climatic and erosional processes, whose relative importance changes over times, while quantifying these processes and their rates at specific times remains a challenge. The eastern Andes of central Bolivia offer a natural laboratory in which such interplay has been debated. Here, we investigate the Rio Grande catchment which crosses orthogonally the eastern Andes orogen from the Eastern Cordillera into the Subandean Zone, exhibiting a catchment relief of up to 5000 m. Despite an enhanced tectonic activity in the Subandes, local relief, mean and modal slopes and channel steepness indices are largely similar compared to the Eastern Cordillera and the intervening Interandean Zone. Nevertheless, a dataset of 57 new cosmogenic 10Be and 26AI catchment wide denudation rates from the Rio Grande catchment reveals up to one order of magnitude higher denudation rates in the Subandean Zone (mean 0.8 mm/yr) compared to the upstream physiographic regions. We infer that tectonic activity in the thrusting dominated Subandean belt causes higher denudation rates based on cumulative rock uplift investigations and due to the absence of a pronounced climate gradient. Furthermore, the lower rock strength of the Subandean sedimentary units correlates with mean slopes similar to the ones of the Eastern Cordillera and Interandean Zone, highlighting the fact, that lithology and rock strength can control high denudation rates at low slopes. Low denudation rates measured at the outlet of the Rio Grande catchment (Abapo) are interpreted to be a result of a biased cosmogenic nuclide mixing that is dominated by headwater signals from the Eastern Cordillera and the Interandean zone and limited catchment sediment connectivity in the lower river reaches. Therefore, comparisons of short- (i.e., sediment yield) and millennial denudation rates require caution when postulating tectonic and/or climatic forcing without detailed studies. (C) 2015 The Authors. Published by Elsevier B.V.}, language = {en} } @article{MulyukovaSteinbergerDabrowskietal.2015, author = {Mulyukova, Elvira and Steinberger, Bernhard and Dabrowski, Marcin and Sobolev, Stephan Vladimir}, title = {Survival of LLSVPs for billions of years in a vigorously convecting mantle: Replenishment and destruction of chemical anomaly}, series = {Journal of geophysical research : Solid earth}, volume = {120}, journal = {Journal of geophysical research : Solid earth}, number = {5}, publisher = {American Geophysical Union}, address = {Washington}, issn = {2169-9313}, doi = {10.1002/2014JB011688}, pages = {3824 -- 3847}, year = {2015}, abstract = {We study segregation of the subducted oceanic crust (OC) at the core-mantle boundary and its ability to accumulate and form large thermochemical piles (such as the seismically observed Large Low Shear Velocity Provinces (LLSVPs)). Our high-resolution numerical simulations of thermochemical mantle convection suggest that the longevity of LLSVPs for up to three billion years, and possibly longer, can be ensured by a balance in the rate of segregation of high-density OC material to the core-mantle boundary (CMB) and the rate of its entrainment away from the CMB by mantle upwellings. For a range of parameters tested in this study, a large-scale compositional anomaly forms at the CMB, similar in shape and size to the LLSVPs. Neutrally buoyant thermochemical piles formed by mechanical stirringwhere thermally induced negative density anomaly is balanced by the presence of a fraction of dense anomalous materialbest resemble the geometry of LLSVPs. Such neutrally buoyant piles tend to emerge and survive for at least 3Gyr in simulations with quite different parameters. We conclude that for a plausible range of values of density anomaly of OC material in the lower mantleit is likely that it segregates to the CMB, gets mechanically mixed with the ambient material, and forms neutrally buoyant large-scale compositional anomalies similar in shape to the LLSVPs.}, language = {en} } @article{LeFriantIshizukaBoudonetal.2015, author = {Le Friant, A. and Ishizuka, O. and Boudon, G. and Palmer, M. R. and Talling, P. J. and Villemant, B. and Adachi, T. and Aljahdali, M. and Breitkreuz, C. and Brunet, M. and Caron, B. and Coussens, M. and Deplus, C. and Endo, D. and Feuillet, N. and Fraas, A. J. and Fujinawa, A. and Hart, M. B. and Hatfield, R. G. and Hornbach, M. and Jutzeler, M. and Kataoka, K. S. and Komorowski, J. -C. and Lebas, E. and Lafuerza, S. and Maeno, F. and Manga, M. and Martinez-Colon, M. and McCanta, M. and Morgan, S. and Saito, T. and Slagle, A. and Sparks, S. and Stinton, A. and Stroncik, Nicole and Subramanyam, K. S. V. and Tamura, Yui and Trofimovs, J. and Voight, B. and Wall-Palmer, D. and Wang, F. and Watt, S. F. L.}, title = {Submarine record of volcanic island construction and collapse in the Lesser Antilles arc: First scientific drilling of submarine volcanic island landslides by IODP Expedition 340}, series = {Geochemistry, geophysics, geosystems}, volume = {16}, journal = {Geochemistry, geophysics, geosystems}, number = {2}, publisher = {American Geophysical Union}, address = {Washington}, issn = {1525-2027}, doi = {10.1002/2014GC005652}, pages = {420 -- 442}, year = {2015}, abstract = {IODP Expedition 340 successfully drilled a series of sites offshore Montserrat, Martinique and Dominica in the Lesser Antilles from March to April 2012. These are among the few drill sites gathered around volcanic islands, and the first scientific drilling of large and likely tsunamigenic volcanic island-arc landslide deposits. These cores provide evidence and tests of previous hypotheses for the composition and origin of those deposits. Sites U1394, U1399, and U1400 that penetrated landslide deposits recovered exclusively seafloor sediment, comprising mainly turbidites and hemipelagic deposits, and lacked debris avalanche deposits. This supports the concepts that i/ volcanic debris avalanches tend to stop at the slope break, and ii/ widespread and voluminous failures of preexisting low-gradient seafloor sediment can be triggered by initial emplacement of material from the volcano. Offshore Martinique (U1399 and 1400), the landslide deposits comprised blocks of parallel strata that were tilted or microfaulted, sometimes separated by intervals of homogenized sediment (intense shearing), while Site U1394 offshore Montserrat penetrated a flat-lying block of intact strata. The most likely mechanism for generating these large-scale seafloor sediment failures appears to be propagation of a decollement from proximal areas loaded and incised by a volcanic debris avalanche. These results have implications for the magnitude of tsunami generation. Under some conditions, volcanic island landslide deposits composed of mainly seafloor sediment will tend to form smaller magnitude tsunamis than equivalent volumes of subaerial block-rich mass flows rapidly entering water. Expedition 340 also successfully drilled sites to access the undisturbed record of eruption fallout layers intercalated with marine sediment which provide an outstanding high-resolution data set to analyze eruption and landslides cycles, improve understanding of magmatic evolution as well as offshore sedimentation processes.}, language = {en} } @article{OverduinHaberlandRybergetal.2015, author = {Overduin, Pier Paul and Haberland, Christian and Ryberg, Trond and Kneier, Fabian and Jacobi, Tim and Grigoriev, Mikhail N. and Ohrnberger, Matthias}, title = {Submarine permafrost depth from ambient seismic noise}, series = {Geophysical research letters}, volume = {42}, journal = {Geophysical research letters}, number = {18}, publisher = {American Geophysical Union}, address = {Washington}, issn = {0094-8276}, doi = {10.1002/2015GL065409}, pages = {7581 -- 7588}, year = {2015}, abstract = {Permafrost inundated since the last glacial maximum is degrading, potentially releasing trapped or stabilized greenhouse gases, but few observations of the depth of ice-bonded permafrost (IBP) below the seafloor exist for most of the arctic continental shelf. We use spectral ratios of the ambient vibration seismic wavefield, together with estimated shear wave velocity from the dispersion curves of surface waves, for estimating the thickness of the sediment overlying the IBP. Peaks in spectral ratios modeled for three-layered 1-D systems correspond with varying thickness of the unfrozen sediment. Seismic receivers were deployed on the seabed around Muostakh Island in the central Laptev Sea, Siberia. We derive depths of the IBP between 3.7 and 20.7m15\%, increasing with distance from the shoreline. Correspondence between expected permafrost distribution, modeled response, and observational data suggests that the method is promising for the determination of the thickness of unfrozen sediment.}, language = {en} } @article{WilkeSchmidtZiemann2015, author = {Wilke, Franziska Daniela Helena and Schmidt, Alexander and Ziemann, Martin Andreas}, title = {Subduction, peak and multi-stage exhumation metamorphism: Traces from one coesite-bearing eclogite, Tso Moran, western Himalaya}, series = {Lithos : an international journal of mineralogy, petrology, and geochemistry}, volume = {231}, journal = {Lithos : an international journal of mineralogy, petrology, and geochemistry}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0024-4937}, doi = {10.1016/j.lithos2015.06.007}, pages = {77 -- 91}, year = {2015}, abstract = {Ultrahigh-pressure (UHP), coesite-bearing edogites in the Himalaya have been documented from the Kaghan Valley in Pakistan and the Tso Morani area in northwest India. These complexes are part of the northern edge of the Indian plate that has been subducted to, and metamorphosed at, mantle depths of more than 100 km before being exhumed. Both UHP complexes are located today directly adjacent to the Indus-Tsangpo suture zone and are not separated by non-metamorphosed sequences of Tethyan sediments from the Asian margin. Herein, we present new data for one fresh coesite-bearing eclogite from the Tso Moran massif. Therein, garnets are zoned reflecting their growth during prograde and peak metamorphism and showing a thin retrograde overgrowth. Inclusions can be directly correlated to the compositional zoning and are seen as either relicts of the protolith mineral paragenesis and as "snap shots" of the mineral paragenesis during subduction and under peak conditions. Rare earth element concentrations (REE) were obtained for garnet, mineral inclusions in garnet and matrix minerals. The REE pattern in garnet reflects a sequential change in matrix minerals and their proportions due to net transfer reactions during subduction and peak metamorphism. Using conventional geothermobarometry, a peak pressure of ca. 44-48 kbar at 560-760 degrees C followed by an S-shaped exhumation curve has been deduced. Gibbs free energy minimization modelling was used to supplement our analytical findings. (C) 2015 Elsevier B.V. All rights reserved.}, language = {en} } @article{PassarelliRivaltaCescaetal.2015, author = {Passarelli, Luigi and Rivalta, Eleonora and Cesca, Simone and Aoki, Yosuke}, title = {Stress changes, focal mechanisms, and earthquake scaling laws for the 2000 dike at Miyakejima (Japan)}, series = {Journal of geophysical research : Solid earth}, volume = {120}, journal = {Journal of geophysical research : Solid earth}, number = {6}, publisher = {American Geophysical Union}, address = {Washington}, issn = {2169-9313}, doi = {10.1002/2014JB011504}, pages = {4130 -- 4145}, year = {2015}, abstract = {Faulting processes in volcanic areas result from a complex interaction of pressurized fluid-filled cracks and conduits with the host rock and local and regional tectonic setting. Often, volcanic seismicity is difficult to decipher in terms of the physical processes involved, and there is a need for models relating the mechanics of volcanic sources to observations. Here we use focal mechanism data of the energetic swarm induced by the 2000 dike intrusion at Miyakejima (Izu Archipelago, Japan), to study the relation between the 3-D dike-induced stresses and the characteristics of the seismicity. We perform a clustering analysis on the focal mechanism (FM) solutions and relate them to the dike stress field and to the scaling relationships of the earthquakes. We find that the strike and rake angles of the FMs are strongly correlated and cluster on bands in a strike-rake plot. We suggest that this is consistent with optimally oriented faults according to the expected pattern of Coulomb stress changes. We calculate the frequency-size distribution of the clustered sets finding that focal mechanisms with a large strike-slip component are consistent with the Gutenberg-Richter relation with a b value of about 1. Conversely, events with large normal faulting components deviate from the Gutenberg-Richter distribution with a marked roll-off on its right-hand tail, suggesting a lack of large-magnitude events (M-w>5.5). This may result from the interplay of the limited thickness and lower rock strength of the layer of rock above the dike, where normal faulting is expected, and lower stress levels linked to the faulting style and low confining pressure.}, language = {en} } @article{BartholdWoods2015, author = {Barthold, Frauke Katrin and Woods, Ross A.}, title = {Stormflow generation: A meta-analysis of field evidence from small, forested catchments}, series = {Water resources research}, volume = {51}, journal = {Water resources research}, number = {5}, publisher = {American Geophysical Union}, address = {Washington}, issn = {0043-1397}, doi = {10.1002/2014WR016221}, pages = {3730 -- 3753}, year = {2015}, abstract = {Combinations of runoff characteristics are commonly used to represent distinct conceptual models of stormflow generation. In this study, three runoff characteristics: hydrograph response, time source of runoff water, and flow path are used to classify catchments. Published data from the scientific literature are used to provide evidence from small, forested catchments. Each catchment was assigned to one of the eight conceptual models, depending on the combination of quick/slow response, old/new water, and overland/subsurface flow. A standard procedure was developed to objectively diagnose the predominant conceptual model of stormflow generation for each catchment and assess its temporal and spatial support. The literature survey yielded 42 catchments, of which 30 catchments provide a complete set of qualitative runoff characteristics resulting in one of the eight conceptual models. The majority of these catchments classify as subsurface flow path dominated. No catchments were found for conceptual models representing combinations of quick response-new water-subsurface flow (SSF), slow-new-SSF, slow-old-overland flow (OF) nor new-slow-OF. Of the 30 qualitatively classified catchments, 24 provide a complete set of quantitative measures. In summary, the field support is strong for 19 subsurface-dominated catchments and is weak for 5 surface flow path dominated catchments (six catchments had insufficient quantitative data). Two alternative explanations exist for the imbalance of field support between the two flow path classes: (1) the selection of research catchments in past field studies was mainly to explain quick hydrograph response in subsurface dominated catchments; (2) catchments with prevailing subsurface flow paths are more common in nature. We conclude that the selection of research catchments needs to cover a wider variety of environmental conditions which should lead to a broader, and more widely applicable, spectrum of resulting conceptual models and process mechanisms. This is a prerequisite in studies where catchment organization and similarity approaches are used to develop catchment classification systems in order to regionalize stormflow.}, language = {en} } @phdthesis{Mulyukova2015, author = {Mulyukova, Elvira}, title = {Stability of the large low shear velocity provinces}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-82228}, school = {Universit{\"a}t Potsdam}, pages = {139}, year = {2015}, abstract = {We study segregation of the subducted oceanic crust (OC) at the core mantle boundary and its ability to accumulate and form large thermochemical piles (such as the seismically observed Large Low Shear Velocity Provinces - LLSVPs). Our high-resolution numerical simulations suggest that the longevity of LLSVPs for up to three billion years, and possibly longer, can be ensured by a balance in the rate of segregation of high-density OC-material to the CMB, and the rate of its entrainment away from the CMB by mantle upwellings. For a range of parameters tested in this study, a large-scale compositional anomaly forms at the CMB, similar in shape and size to the LLSVPs. Neutrally buoyant thermochemical piles formed by mechanical stirring - where thermally induced negative density anomaly is balanced by the presence of a fraction of dense anomalous material - best resemble the geometry of LLSVPs. Such neutrally buoyant piles tend to emerge and survive for at least 3Gyr in simulations with quite different parameters. We conclude that for a plausible range of values of density anomaly of OC material in the lower mantle - it is likely that it segregates to the CMB, gets mechanically mixed with the ambient material, and forms neutrally buoyant large scale compositional anomalies similar in shape to the LLSVPs. We have developed an efficient FEM code with dynamically adaptive time and space resolution, and marker-in-cell methodology. This enabled us to model thermochemical mantle convection at realistically high convective vigor, strong thermally induced viscosity variations, and long term evolution of compositional fields.}, language = {en} } @phdthesis{Brosinsky2015, author = {Brosinsky, Arlena}, title = {Spectral fingerprinting}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-83369}, school = {Universit{\"a}t Potsdam}, pages = {VI, 117}, year = {2015}, abstract = {Current research on runoff and erosion processes, as well as an increasing demand for sustainable watershed management emphasize the need for an improved understanding of sediment dynamics. This involves the accurate assessment of erosion rates and sediment transfer, yield and origin. A variety of methods exist to capture these processes at the catchment scale. Among these, sediment fingerprinting, a technique to trace back the origin of sediment, has attracted increasing attention by the scientific community in recent years. It is a two-step procedure, based on the fundamental assumptions that potential sources of sediment can be reliably discriminated based on a set of characteristic 'fingerprint' properties, and that a comparison of source and sediment fingerprints allows to quantify the relative contribution of each source. This thesis aims at further assessing the potential of spectroscopy to assist and improve the sediment fingerprinting technique. Specifically, this work focuses on (1) whether potential sediment sources can be reliably identified based on spectral features ('fingerprints'), whether (2) these spectral fingerprints permit the quantification of relative source contribution, and whether (3) in situ derived source information is sufficient for this purpose. Furthermore, sediment fingerprinting using spectral information is applied in a study catchment to (4) identify major sources and observe how relative source contributions change between and within individual flood events. And finally, (5) spectral fingerprinting results are compared and combined with simultaneous sediment flux measurements to study sediment origin, transport and storage behaviour. For the sediment fingerprinting approach, soil samples were collected from potential sediment sources within the Is{\´a}bena catchment, a meso-scale basin in the central Spanish Pyrenees. Undisturbed samples of the upper soil layer were measured in situ using an ASD spectroradiometer and subsequently sampled for measurements in the laboratory. Suspended sediment was sampled automatically by means of ISCO samplers at the catchment as well as at the five major subcatchment outlets during flood events, and stored fine sediment from the channel bed was collected from 14 cross-sections along the main river. Artificial mixtures of known contributions were produced from source soil samples. Then, all source, sediment and mixture samples were dried and spectrally measured in the laboratory. Subsequently, colour coefficients and physically based features with relation to organic carbon, iron oxide, clay content and carbonate, were calculated from all in situ and laboratory spectra. Spectral parameters passing a number of prerequisite tests were submitted to principal component analyses to study natural clustering of samples, discriminant function analyses to observe source differentiation accuracy, and a mixing model for source contribution assessment. In addition, annual as well as flood event based suspended sediment fluxes from the catchment and its subcatchments were calculated from rainfall, water discharge and suspended sediment concentration measurements using rating curves and Quantile Regression Forests. Results of sediment flux monitoring were interpreted individually with respect to storage behaviour, compared to fingerprinting source ascriptions and combined with fingerprinting to assess their joint explanatory potential. In response to the key questions of this work, (1) three source types (land use) and five spatial sources (subcatchments) could be reliably discriminated based on spectral fingerprints. The artificial mixture experiment revealed that while (2) laboratory parameters permitted source contribution assessment, (3) the use of in situ derived information was insufficient. Apparently, high discrimination accuracy does not necessarily imply good quantification results. When applied to suspended sediment samples of the catchment outlet, the spectral fingerprinting approach was able to (4) quantify the major sediment sources: badlands and the Villacarli subcatchment, respectively, were identified as main contributors, which is consistent with field observations and previous studies. Thereby, source contribution was found to vary both, within and between individual flood events. Also sediment flux was found to vary considerably, annually as well as seasonally and on flood event base. Storage was confirmed to play an important role in the sediment dynamics of the studied catchment, whereas floods with lower total sediment yield tend to deposit and floods with higher yield rather remove material from the channel bed. Finally, a comparison of flux measurements with fingerprinting results highlighted the fact that (5) immediate transport from sources to the catchment outlet cannot be assumed. A combination of the two methods revealed different aspects of sediment dynamics that none of the techniques could have uncovered individually. In summary, spectral properties provide a fast, non-destructive, and cost-efficient means to discriminate and quantify sediment sources, whereas, unfortunately, straight-forward in situ collected source information is insufficient for the approach. Mixture modelling using artificial mixtures permits valuable insights into the capabilities and limitations of the method and similar experiments are strongly recommended to be performed in the future. Furthermore, a combination of techniques such as e.g. (spectral) sediment fingerprinting and sediment flux monitoring can provide comprehensive understanding of sediment dynamics.}, language = {en} } @article{CaoHerzschuhNietal.2015, author = {Cao, Xianyong and Herzschuh, Ulrike and Ni, Jian and Zhao, Yan and B{\"o}hmer, Thomas}, title = {Spatial and temporal distributions of major tree taxa in eastern continental Asia during the last 22,000 years}, series = {The Holocene : an interdisciplinary journal focusing on recent environmental change}, volume = {25}, journal = {The Holocene : an interdisciplinary journal focusing on recent environmental change}, number = {1}, publisher = {Sage Publ.}, address = {London}, issn = {0959-6836}, doi = {10.1177/0959683614556385}, pages = {79 -- 91}, year = {2015}, abstract = {This study investigates the spatial and temporal distributions of 14 key arboreal taxa and their driving forces during the last 22,000 calendar years before ad 1950 (kyr BP) using a taxonomically harmonized and temporally standardized fossil pollen dataset with a 500-year resolution from the eastern part of continental Asia. Logistic regression was used to estimate pollen abundance thresholds for vegetation occurrence (presence or dominance), based on modern pollen data and present ranges of 14 taxa in China. Our investigation reveals marked changes in spatial and temporal distributions of the major arboreal taxa. The thermophilous (Castanea, Castanopsis, Cyclobalanopsis, Fagus, Pterocarya) and eurythermal (Juglans, Quercus, Tilia, Ulmus) broadleaved tree taxa were restricted to the current tropical or subtropical areas of China during the Last Glacial Maximum (LGM) and spread northward since c. 14.5kyr BP. Betula and conifer taxa (Abies, Picea, Pinus), in contrast, retained a wider distribution during the LGM and showed no distinct expansion direction during the Late Glacial. Since the late mid-Holocene, the abundance but not the spatial extent of most trees decreased. The changes in spatial and temporal distributions for the 14 taxa are a reflection of climate changes, in particular monsoonal moisture, and, in the late Holocene, human impact. The post-LGM expansion patterns in eastern continental China seem to be different from those reported for Europe and North America, for example, the westward spread for eurythermal broadleaved taxa.}, language = {en} } @article{FrommPlanertJokatetal.2015, author = {Fromm, T. and Planert, Lars and Jokat, Wilfried and Ryberg, Trond and Behrmann, Jan H. and Weber, Michael H. and Haberland, Christian}, title = {South Atlantic opening: A plume-induced breakup?}, series = {Geology}, volume = {43}, journal = {Geology}, number = {10}, publisher = {American Institute of Physics}, address = {Boulder}, issn = {0091-7613}, doi = {10.1130/G36936.1}, pages = {931 -- 934}, year = {2015}, abstract = {Upwelling hot mantle plumes are thought to disintegrate continental lithosphere and are considered to be drivers of active continental breakup. The formation of the Walvis Ridge during the opening of the South Atlantic is related to a putative plume-induced breakup. We investigated the crustal structure of the Walvis Ridge (southeast Atlantic Ocean) at its intersection with the continental margin and searched for anomalies related to the possible plume head. The overall structure we identify suggests that no broad plume head existed during opening of the South Atlantic and anomalous mantle melting occurred only locally. We therefore question the importance of a plume head as a driver of continental breakup and further speculate that the hotspot was present before the rifting, leaving a track of kimberlites in the African craton.}, language = {en} }