@article{AichnerHerzschuhWilkesetal.2012, author = {Aichner, Bernhard and Herzschuh, Ulrike and Wilkes, Heinz and Schulz, Hans-Martin and Wang, Yongbo and Plessen, Birgit and Mischke, Steffen and Diekmann, Bernhard and Zhang, Chengjun}, title = {Ecological development of Lake Donggi Cona, north-eastern Tibetan Plateau, since the late glacial on basis of organic geochemical proxies and non-pollen palynomorphs}, series = {Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences}, volume = {313}, journal = {Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences}, number = {2}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0031-0182}, doi = {10.1016/j.palaeo.2011.10.015}, pages = {140 -- 149}, year = {2012}, abstract = {Organic geochemical proxy data from surface sediment samples and a sediment core from Lake Donggi Cona were used to infer environmental changes on the northeastern Tibetan Plateau spanning the last 18.4 kyr. Long-chain n-alkanes dominate the aliphatic hydrocarbon fraction of the sediment extract from most surface sediment samples and the sediment core. Unsaturated mid-chain n-alkanes (nC(23:1) and nC(25:1)) have high abundances in some samples, especially in core samples from the late glacial and early Holocene. TOC contents, organic biomarker and non-pollen-palynomorph concentrations and results from organic petrologic analysis on selected samples suggest three major episodes in the history of Lake Donggi Cona. Before ca. 12.6 cal ka BP samples contain low amounts of organic matter due to cold and arid conditions during the late glacial. After 12.6 cal ka BP, relatively high contents of TOC and concentrations of Botryococcus fossils, as well as enhanced concentrations of mid-chain n-alkanes and n-alkenes suggest a higher primary and macrophyte productivity than at present This is supported by high contents of palynomorphs derived from higher plants and algae and was possibly triggered by a decrease of salinity and amelioration of climate during the early Holocene. Since 6.8 cal ka BP Lake Donggi Cona has been an oligotrophic freshwater lake. Proxy data suggest that variations in insolation drive ecological changes in the lake, with increased aquatic productivity during the early Holocene summer insolation maximum. Short-term drops of TOC contents or biomarker concentrations (at 9.9 cal ka BP, after 8.0 and between 3.5 and 1.7 cal ka BP) can possibly be related to relatively cool and dry episodes reported from other sites on the north-eastern Tibetan Plateau, which are hypothesized to occur in phase with Northern Hemisphere cooling events.}, language = {en} } @article{AkalCandanKoralayetal.2012, author = {Akal, C{\"u}neyt and Candan, Osman and Koralay, O. Ersin and Oberh{\"a}nsli, Roland and Chen, Fukun and Prelevic, Dejan}, title = {Early Triassic potassic volcanism in the Afyon Zone of the Anatolides/Turkey - implications for the rifting of the Neo-Tethys}, series = {International journal of earth sciences}, volume = {101}, journal = {International journal of earth sciences}, number = {1}, publisher = {Springer}, address = {New York}, issn = {1437-3254}, doi = {10.1007/s00531-011-0654-2}, pages = {177 -- 194}, year = {2012}, abstract = {Afyon Zone, which was derived from the Anatolide-Tauride platform during closure of the Neo-Tethys, is made up of pre-Mesozoic basement and unconformably overlying Triassic-Early Tertiary cover series. The Afyon Zone contains widespread metavolcanic rocks, which are dominated by rhyolite, dacite, and trachyandesite. They form a distinct volcanic succession, which is separated from the underlying Silurian-Lower Carboniferous metacarbonates and meta-siliciclastics by a regional unconformity. Trachyandesitic metavolcanics are made up of massive lava flows, pyroclastics and epiclastics, less frequently, domes and dikes, which were developed on a deeply eroded subaerial landmass. U/Pb and Pb/Pb zircon geochronology yielded Lower Triassic (similar to 250 Ma) ages, which are interpreted as extrusion age of trachyandesitic volcanics. Based on the stratigraphic, geochronological, and geochemical data, we suggest that these Lower Triassic magmatic rocks represent an extensional tectonic setting on the northern active margin of the Gondwana, which led to the development of the northern branch of the Neo-Tethys.}, language = {en} } @article{AlMashaikhiOswaldAttingeretal.2012, author = {Al-Mashaikhi, K. and Oswald, Sascha and Attinger, Sabine and B{\"u}chel, G. and Kn{\"o}ller, K. and Strauch, G.}, title = {Evaluation of groundwater dynamics and quality in the Najd aquifers located in the Sultanate of Oman}, series = {Environmental earth sciences}, volume = {66}, journal = {Environmental earth sciences}, number = {4}, publisher = {Springer}, address = {New York}, issn = {1866-6280}, doi = {10.1007/s12665-011-1331-2}, pages = {1195 -- 1211}, year = {2012}, abstract = {The Najd, Oman, is located in one of the most arid environments in the world. The groundwater in this region is occurring in four different aquifers A to D of the Hadhramaut Group consisting mainly of different types of limestone and dolomite. The quality of the groundwater is dominated by the major ions sodium, calcium, magnesium, sulphate, and chloride, but the hydrochemical character is varying among the four aquifers. Mineralization within the separate aquifers increases along the groundwater flow direction from south to north-northeast up to high saline sodium-chloride water in aquifer D in the northeast area of the Najd. Environmental isotope analyses of hydrogen and oxygen were conducted to monitor the groundwater dynamics and to evaluate the recharge conditions of groundwater into the Najd aquifers. Results suggest an earlier recharge into these aquifers as well as ongoing recharge takes place in the region down to present day. Mixing of modern and submodern waters was detected by water isotopes in aquifer D in the mountain chain (Jabal) area and along the northern side of the mountain range. In addition, delta H-2 and delta O-18 variations suggest that aquifers A, B, and C are assumed to be connected by faults and fractures, and interaction between the aquifers may occur. Low tritium concentrations support the mixing assumption in the recharge area. The knowledge about the groundwater development is an important factor for the sustainable use of water resources in the Dhofar region.}, language = {en} } @article{AltenbergerMejiaJimenezGuenteretal.2012, author = {Altenberger, Uwe and Mejia Jimenez, D. M. and G{\"u}nter, C. and Sierra Rodriguez, G. I. and Scheffler, F. and Oberh{\"a}nsli, Roland}, title = {The Garzn Massif, Colombia-a new ultrahigh-temperature metamorphic complex in the early Neoproterozoic of northern South America}, series = {Mineralogy and petrology}, volume = {105}, journal = {Mineralogy and petrology}, number = {3-4}, publisher = {Springer}, address = {Wien}, issn = {0930-0708}, doi = {10.1007/s00710-012-0202-1}, pages = {171 -- 185}, year = {2012}, abstract = {The Garzn Complex of the Garzn Massif in SW Colombia is composed of the Vergel Granulite Unit (VG) and the Las Margaritas Migmatite Unit (LMM). Previous studies reveal peak temperature conditions for the VG of about 740 A degrees C. The present study considers the remarkable exsolution phenomena in feldspars and pyroxenes and titanium-in-quartz thermometry. Recalculated ternary feldspar compositions indicate temperatures around 900-1,000 A degrees C just at or above the ultra-high temperature-metamorphism (UHTM) boundary of granulites. The calculated temperatures range of exsolved ortho- and clinopyroxenes also supports the existence of an UHTM event. In addition, titanium-in-quartz thermometry points towards ultra-high temperatures. It is the first known UHTM crustal segment in the northern part of South America. Although a mean geothermal gradient of ca 38 A degrees C km(-1) could imply additional heat supply in the lower crust controlling this extreme of peak metamorphism, an alternative model is suggested. The formation of the Vergel Granulite Unit is supposed to be formed in a continental back-arc environment with a thinned and weakened crust behind a magmatic arc (Guapotn-Mancagua Gneiss) followed by collision. In contrast, rocks of the adjacent Las Margaritas Migmatite Unit display "normal" granulite facies temperatures and are formed in a colder lower crust outside the arc, preserved by the Guapotn-Mancagu Gneiss. Back-arc formation was followed by inversion and thickening of the basin. The three units that form the modern-day Garzn Massif, were juxtaposed upon each other during collision (at ca. 1,000 Ma) and exhumation. The collision leading to the deformation of the studied area is part of the Grenville orogeny leading to the amalgamation of Rodinia.}, language = {en} } @phdthesis{Ambili2012, author = {Ambili, Anoop}, title = {Lake sediments as climate and tectonic archives in the Indian summer monsoon domain}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-64799}, school = {Universit{\"a}t Potsdam}, year = {2012}, abstract = {The Indian summer monsoon (ISM) is one of the largest climate systems on earth and impacts the livelihood of nearly 40\% of the world's population. Despite dedicated efforts, a comprehensive picture of monsoon variability has proved elusive largely due to the absence of long term high resolution records, spatial inhomogeneity of the monsoon precipitation, and the complex forcing mechanisms (solar insolation, internal teleconnections for e.g., El Ni{\~n}o-Southern Oscillation, tropical-midlatitude interactions). My work aims to improve the understanding of monsoon variability through generation of long term high resolution palaeoclimate data from climatically sensitive regions in the ISM and westerlies domain. To achieve this aim I have (i) identified proxies (sedimentological, geochemical, isotopic, and mineralogical) that are sensitive to environmental changes; (ii) used the identified proxies to generate long term palaeoclimate data from two climatically sensitive regions, one in NW Himalayas (transitional westerlies and ISM domain in the Spiti valley and one in the core monsoon zone (Lonar lake) in central India); (iii) undertaken a regional overview to generate "snapshots" of selected time slices; and (iv) interpreted the spatial precipitation anomalies in terms of those caused by modern teleconnections. This approach must be considered only as the first step towards identifying the past teleconnections as the boundary conditions in the past were significantly different from today and would have impacted the precipitation anomalies. As the Spiti valley is located in the in the active tectonic orogen of Himalayas, it was essential to understand the role of regional tectonics to make valid interpretations of catchment erosion and detrital influx into the lake. My approach of using integrated structural/morphometric and geomorphic signatures provided clear evidence for active tectonics in this area and demonstrated the suitability of these lacustrine sediments as palaleoseismic archives. The investigations on the lacustrine outcrops in Spiti valley also provided information on changes in seasonality of precipitation and occurrence of frequent and intense periods (ca. 6.8-6.1 cal ka BP) of detrital influx indicating extreme hydrological events in the past. Regional comparison for this time slice indicates a possible extended "break-monsoon like" mode for the monsoon that favors enhanced precipitation over the Tibetan plateau, Himalayas and their foothills. My studies on surface sediments from Lonar lake helped to identify environmentally sensitive proxies which could also be used to interpret palaeodata obtained from a ca. 10m long core raised from the lake in 2008. The core encompasses the entire Holocene and is the first well dated (by 14C) archive from the core monsoon zone of central India. My identification of authigenic evaporite gaylussite crystals within the core sediments provided evidence of exceptionally drier conditions during 4.7-3.9 and 2.0-0.5 cal ka BP. Additionally, isotopic investigations on these crystals provided information on eutrophication, stratification, and carbon cycling processes in the lake.}, language = {en} } @article{AndermannCraveGloaguenetal.2012, author = {Andermann, Christoff and Crave, Alain and Gloaguen, Richard and Davy, Philippe and Bonnet, Stephane}, title = {Connecting source and transport: Suspended sediments in the Nepal Himalayas}, series = {Earth \& planetary science letters}, volume = {351}, journal = {Earth \& planetary science letters}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0012-821X}, doi = {10.1016/j.epsl.2012.06.059}, pages = {158 -- 170}, year = {2012}, abstract = {Understanding the dynamics of sediment fluxes is a key issue to constrain modern erosion rates in mountain belts and determine the still debated level of control exerted by precipitation, topography and tectonics. The well defined monsoon seasonality in the Himalayas, together with active tectonics and strong relief provide an ideal environment to assess these possible interactions. For this purpose, we present a new compilation of daily suspended sediment data for 12 stations of the major rivers of the Nepal Himalayas. We analyze the relationships of sediment transport with daily river discharge and precipitation data as well as with morphometric parameters. We show that suspended sediment concentrations vary systematically through the seasons and asynchronously to river discharge displaying a hysteresis effect. This clockwise hysteresis effect disappears when suspended sediment fluxes are directly compared with direct storm discharge. Therefore we attribute the hysteresis effect to groundwater dilution rather than a sediment supply limitation. We infer a rating model to calculate erosion rates directly from long river discharge chronicles. We show that, when normalized by drainage area and mean sediment flux, all rivers exhibit the same trend. This similarity implies that all river basins have the same erosion behavior, independent of location, size and catchment characteristics. Erosion rates calculated from suspended sediment fluxes range between 0.1 and 2.8 mm/yr. The erosion rates of the three main basins of Nepal are in the range 0.9-1.5 mm/yr. Erosion rates in the Higher Himalayas are relatively low ( <0.5 mm/yr, except for Kali Gandaki), while in the Lesser Himalayas they range from 0.2 to 2 mm/yr. We propose that material transport in the rivers depends on hillslope sediment supply, which is, in turn, controlled by those rainfalls producing direct runoff. In other words, the rivers in the Nepal Himalayas are supply-limited and the hillsopes as a contributing source are transport-limited. We also show that erosion processes are not as much controlled by infrequently occurring extreme precipitation events, than by moderate ones with a high recurrence interval.}, language = {en} } @article{AnoopPrasadBasavaiahetal.2012, author = {Anoop, A. and Prasad, S. and Basavaiah, Nathani and Brauer, Achim and Shahzad, F. and Deenadayalan, K.}, title = {Tectonic versus climate influence on landscape evolution: A case study from the upper Spiti valley, NW Himalaya}, series = {Geomorphology : an international journal on pure and applied geomorphology}, volume = {145}, journal = {Geomorphology : an international journal on pure and applied geomorphology}, number = {4}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0169-555X}, doi = {10.1016/j.geomorph.2011.10.028}, pages = {32 -- 44}, year = {2012}, abstract = {We have undertaken structural, geomorphological, and morphometric analyses to investigate the role of tectonism and climate in the landscape evolution in the upper Spiti valley, NW Himalayas. Geomorphometric analyses coupled with field investigations reveal active tectonic deformation in the Spiti region. The calculated geomorphic indices (steepness, concavity and Hack) demonstrate uplift/subsidence along the Kaurik-Chango fault, whereas transverse topographic index (T-index) reveals basin tilting associated with active faulting near Hansa and Lingti valley. Investigation of well-dated Mane palaeolake sediments also provides evidence of regional tectonic instability. Four episodes (ca. 7.8, 7.4, 6.5 and 6.1 cal ka) of neotectonic activity have been identified during the period of the lake's existence. We have also compiled data on the regional climate variability and compared it with the age of the Mane palaeo-landslide. Our results indicate that the landslide occurred towards the end of the early Holocene intensified monsoon phase and is located near an active fault. Our data on regional tectonic instability and the coincidences of modern and palaeo-landslides with zones of active deformation suggest that tectonism is an important factor governing landscape stability in the Spiti region.}, language = {en} } @article{BandeHortonRamirezetal.2012, author = {Bande, Alejandro and Horton, Brian K. and Ramirez, Juan C. and Mora, Andres and Parra, Mauricio and Stockli, Daniel F.}, title = {Clastic deposition, provenance, and sequence of Andean thrusting in the frontal Eastern Cordillera and Llanos foreland basin of Colombia}, series = {Geological Society of America bulletin}, volume = {124}, journal = {Geological Society of America bulletin}, number = {1-2}, publisher = {American Institute of Physics}, address = {Boulder}, issn = {0016-7606}, doi = {10.1130/B30412.1}, pages = {59 -- 76}, year = {2012}, abstract = {Sedimentological, provenance, and detrital thermochronological results for basin fill at the modern deformation front of the northern Andes (6 degrees N latitude) provide a long-term, Eocene to Pliocene record of foreland-basin sedimentation along the Eastern Cordillera !Janos basin boundary in Colombia. Lithofacies assemblages and paleocurrent orientations in the upward-coarsening, 5-km-thick succession of the Nunchia syncline reveal a systematic shift from craton-derived, shallow-marine distal foreland (back-bulge) accumulation in the Mirador Formation, to orogen-sourced, deltaic, and coastalinfluenced sedimentation of the distal to medial foreland (foredeep) in the Carbonera and Leon Formations, to anastomosing fluvial and distributive braided fluvial megafan systems of the proximal foreland (foredeep to wedge-top) basin in the lower and upper Guayabo Formation. These changes in depositional processes and sediment dispersal are supported by up-section variations in detrital zircon U-Pb and (U-Th)/He ages that record exhumation of evolving, compartmentalized sediment source areas in the Eastern Cordillera. The data are interpreted in terms of a progressive eastward advance in foldand-thrust deformation, with late Eocene Oligocene deformation in the axial zone of the Eastern Cordillera along the western edge of Floresta basin (Soapaga thrust), early Miocene reactivation (inversion) of the eastern margin of the Mesozoic rift system (Pajarito and Guaicaramo thrusts), and middle late Miocene propagation of a footwall shortcut fault (Vopal thrust) that created the Nunchia syncline in a wedge-top (piggyback) setting of the eastern foothills along the transition from the Eastern Cordillera to Harms foreland basin. Collectively, the data presented here for the frontal Eastern Cordillera define a general in-sequence pattern of eastwardadvancing fold-and-thrust deformation during Cenozoic east-west shortening in the Colombian Andes.}, language = {en} } @article{BeauvalTasanLaurendeauetal.2012, author = {Beauval, Celine and Tasan, Hilal and Laurendeau, Aurore and Delavaud, Elise and Cotton, Fabrice and Gueguen, Philippe and K{\"u}hn, Nicolas}, title = {On the testing of ground-motion prediction equations against small-magnitude data}, series = {Bulletin of the Seismological Society of America}, volume = {102}, journal = {Bulletin of the Seismological Society of America}, number = {5}, publisher = {Seismological Society of America}, address = {El Cerrito}, issn = {0037-1106}, doi = {10.1785/0120110271}, pages = {1994 -- 2007}, year = {2012}, abstract = {Ground-motion prediction equations (GMPE) are essential in probabilistic seismic hazard studies for estimating the ground motions generated by the seismic sources. In low-seismicity regions, only weak motions are available during the lifetime of accelerometric networks, and the equations selected for the probabilistic studies are usually models established from foreign data. Although most GMPEs have been developed for magnitudes 5 and above, the minimum magnitude often used in probabilistic studies in low-seismicity regions is smaller. Disaggregations have shown that, at return periods of engineering interest, magnitudes less than 5 may be contributing to the hazard. This paper presents the testing of several GMPEs selected in current international and national probabilistic projects against weak motions recorded in France (191 recordings with source-site distances up to 300 km, 3:8 <= M-w <= 4:5). The method is based on the log-likelihood value proposed by Scherbaum et al. (2009). The best-fitting models (approximately 2:5 <= LLH <= 3:5) over the whole frequency range are the Cauzzi and Faccioli (2008), Akkar and Bommer (2010), and Abrahamson and Silva (2008) models. No significant regional variation of ground motions is highlighted, and the magnitude scaling could be the predominant factor in the control of ground-motion amplitudes. Furthermore, we take advantage of a rich Japanese dataset to run tests on randomly selected low-magnitude subsets, and confirm that a dataset of similar to 190 observations, the same size as the French dataset, is large enough to obtain stable LLH estimates. Additionally we perform the tests against larger magnitudes (5-7) from the Japanese dataset. The ranking of models is partially modified, indicating a magnitude scaling effect for some of the models, and showing that extrapolating testing results obtained from low-magnitude ranges to higher magnitude ranges is not straightforward.}, language = {en} } @article{BernhardtJobeGroveetal.2012, author = {Bernhardt, Anne and Jobe, Zane R. and Grove, Marty and Lowe, Donald R.}, title = {Palaeogeography and diachronous infill of an ancient deep-marine foreland basin, Upper Cretaceous Cerro Toro Formation, Magallanes Basin}, series = {Basin research}, volume = {24}, journal = {Basin research}, number = {3}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0950-091X}, doi = {10.1111/j.1365-2117.2011.00528.x}, pages = {269 -- 294}, year = {2012}, abstract = {The details of how narrow, orogen-parallel ocean basins are filled with sediment by large axial submarine channels is important to understand because these depositional systems commonly form in through-like basins in various tectonic settings. The Magallanes foreland basin is an excellent location to study an orogen-parallel deep-marine system. Conglomerate lenses of the Upper Cretaceous Cerro Toro Formation have been previously interpreted to represent the fill of a single submarine channel (48 km wide, >100 km long) that funneled coarse detritus southward along the basin axis. This interpretation was based on lithologic correlations. New U/Pb dating of zircons from volcanic ashes and sandstones, coupled with strontium isotope stratigraphy, refine the controls on depositional ages and provenance. Results demonstrate that north-south oriented conglomerate lenses are contemporaneous within error limits (ca. 8482 Ma) supporting that they represent parts of an axial channel belt. Channel deposits 20 km west of the axial location are 8782 Ma in age. These channels are partly contemporaneous with the ones within the axial channel belt, making it likely that they represent feeders to the axial channel system. The northern Cerro Toro Formation spans a Turonian to Campanian interval (ca. 9082 Ma) whereas the formation top, 70 km to the south, is as young as ca. 76 Ma. KolmogorovSmirnoff statistical analysis on detrital zircon age distributions shows that the northern uppermost Cerro Toro Formation yields a statistically different age distribution than other samples from the same formation but shows no difference relative to the overlying Tres Pasos Formation. These results suggest the partly coeval deposition of both formations. Integration of previously acquired geochronologic and stratigraphic data with new data show a pronounced southward younging pattern in all four marine formations in the Magallanes Basin. Highly diachronous infilling may be an important depositional pattern for narrow, orogen-parallel ocean basins.}, language = {en} } @article{BernhardtStrightLowe2012, author = {Bernhardt, Anne and Stright, Lisa and Lowe, Donald R.}, title = {Channelized debris-flow deposits and their impact on turbidity currents: The Puchkirchen axial channel belt in the Austrian Molasse Basin}, series = {Sedimentology : the journal of the International Association of Sedimentologists}, volume = {59}, journal = {Sedimentology : the journal of the International Association of Sedimentologists}, number = {7}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0037-0746}, doi = {10.1111/j.1365-3091.2012.01334.x}, pages = {2042 -- 2070}, year = {2012}, abstract = {Deposits of submarine debris flows can build up substantial topography on the sea floor. The resulting sea floor morphology can strongly influence the pathways of and deposition from subsequent turbidity currents. Map views of sea floor morphology are available for parts of the modern sea floor and from high-resolution seismic-reflection data. However, these data sets usually lack lithological information. In contrast, outcrops provide cross-sectional and lateral stratigraphic details of deep-water strata with superb lithological control but provide little information on sea floor morphology. Here, a methodology is presented that extracts fundamental lithological information from sediment core and well logs with a novel calibration between core, well-logs and seismic attributes within a large submarine axial channel belt in the Tertiary Molasse foreland basin, Austria. This channel belt was the course of multiple debris-flow and turbidity current events, and the fill consists of interbedded layers deposited by both of these processes. Using the core-well-seismic calibration, three-dimensional lithofacies proportion volumes were created. These volumes enable the interpretation of the three-dimensional distribution of the important lithofacies and thus the investigation of sea floor morphology produced by debris-flow events and its impact on succeeding turbidite deposition. These results show that the distribution of debris-flow deposits follows a relatively regular pattern of levees and lobes. When subsequent high-density turbidity currents encountered this mounded debris-flow topography, they slowed and deposited a portion of their sandy high-density loads just upstream of morphological highs. Understanding the depositional patterns of debris flows is key to understanding and predicting the location and character of associated sandstone accumulations. This detailed model of the filling style and the resulting stratigraphic architecture of a debris-flow dominated deep-marine depositional system can be used as an analogue for similar modern and ancient systems.}, language = {en} } @article{BeyreutherHammerWassermannetal.2012, author = {Beyreuther, Moritz and Hammer, Conny and Wassermann, Joachim and Ohrnberger, Matthias and Megies, Tobias}, title = {Constructing a hidden Markov Model based earthquake detector: application to induced seismicity}, series = {Geophysical journal international}, volume = {189}, journal = {Geophysical journal international}, number = {1}, publisher = {Wiley-Blackwell}, address = {Malden}, issn = {0956-540X}, doi = {10.1111/j.1365-246X.2012.05361.x}, pages = {602 -- 610}, year = {2012}, abstract = {The triggering or detection of seismic events out of a continuous seismic data stream is one of the key issues of an automatic or semi-automatic seismic monitoring system. In the case of dense networks, either local or global, most of the implemented trigger algorithms are based on a large number of active stations. However, in the case of only few available stations or small events, for example, like in monitoring volcanoes or hydrothermal power plants, common triggers often show high false alarms. In such cases detection algorithms are of interest, which show reasonable performance when operating even on a single station. In this context, we apply Hidden Markov Models (HMM) which are algorithms borrowed from speech recognition. However, many pitfalls need to be avoided to apply speech recognition technology directly to earthquake detection. We show the fit of the model parameters in an innovative way. State clustering is introduced to refine the intrinsically assumed time dependency of the HMMs and we explain the effect coda has on the recognition results. The methodology is then used for the detection of anthropogenicly induced earthquakes for which we demonstrate for a period of 3.9 months of continuous data that the single station HMM earthquake detector can achieve similar detection rates as a common trigger in combination with coincidence sums over two stations. To show the general applicability of state clustering we apply the proposed method also to earthquake classification at Mt. Merapi volcano, Indonesia.}, language = {en} } @phdthesis{Biskaborn2012, author = {Biskaborn, Boris}, title = {Holocene environmental variability inferred from lake diatoms and sediment geochemistry in northeastern Siberia, Russia}, address = {Potsdam}, pages = {139 S.}, year = {2012}, language = {en} } @article{BlaserOhrnbergerKruegeretal.2012, author = {Blaser, Lilian and Ohrnberger, Matthias and Kr{\"u}ger, Frank and Scherbaum, Frank}, title = {Probabilistic tsunami threat assessment of 10 recent earthquakes offshore Sumatra}, series = {Geophysical journal international}, volume = {188}, journal = {Geophysical journal international}, number = {3}, publisher = {Wiley-Blackwell}, address = {Malden}, issn = {0956-540X}, doi = {10.1111/j.1365-246X.2011.05324.x}, pages = {1273 -- 1284}, year = {2012}, abstract = {Tsunami early warning (TEW) is a challenging task as a decision has to be made within few minutes on the basis of incomplete and error-prone data. Deterministic warning systems have difficulties in integrating and quantifying the intrinsic uncertainties. In contrast, probabilistic approaches provide a framework that handles uncertainties in a natural way. Recently, we have proposed a method using Bayesian networks (BNs) that takes into account the uncertainties of seismic source parameter estimates in TEW. In this follow-up study, the method is applied to 10 recent large earthquakes offshore Sumatra and tested for its performance. We have evaluated both the general model performance given the best knowledge we have today about the source parameters of the 10 events and the corresponding response on seismic source information evaluated in real-time. We find that the resulting site-specific warning level probabilities represent well the available tsunami wave measurements and observations. Difficulties occur in the real-time tsunami assessment if the moment magnitude estimate is severely over- or underestimated. In general, the probabilistic analysis reveals a considerably large range of uncertainties in the near-field TEW. By quantifying the uncertainties the BN analysis provides important additional information to a decision maker in a warning centre to deal with the complexity in TEW and to reason under uncertainty.}, language = {en} } @article{BoenigerTronicke2012, author = {Boeniger, Urs and Tronicke, Jens}, title = {High-resolution GPR data analysis using extended tree-based pursuit}, series = {Journal of applied geophysics}, volume = {78}, journal = {Journal of applied geophysics}, number = {5}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0926-9851}, doi = {10.1016/j.jappgeo.2011.04.006}, pages = {44 -- 51}, year = {2012}, abstract = {Decomposition of geophysical signals (e.g., seismic and ground-penetrating radar data) into the time-frequency domain can provide valuable information for advanced interpretation (e.g., tuning effects) and processing (e.g., inverse Q-filtering). The quality of these subsequent processing steps is strongly related to the resolution of the selected time-frequency representation (TFR). In this study, we introduce a high-resolution spectral decomposition approach representing an extension of the recently proposed Tree-Based Pursuit (TBP) method. TBP significantly reduces the computational cost compared to the well known Matching Pursuit (MP) technique by introducing a tree structure prior to the actual matching procedure. Following the original implementation of TBP, we additionally incorporate waveforms commonly used in geophysical data processing and present an alternative approach to take phase shifts into account. Application of the proposed method to synthetic data and comparison of the results with other typically used decomposition approaches, illustrate the ability of our approach to provide decomposition results highly localized in both time and frequency. Applying our procedure to field GPR data illustrates its applicability to real data and provides examples for potential applications such as analyzing thin-bed responses and modulating the data frequency content.}, language = {en} } @article{BommGuenterStumpe2012, author = {Bomm, Jana and G{\"u}nter, Christina and Stumpe, Joachim}, title = {Synthesis and optical characterization of thermosensitive, luminescent gold nanodots}, series = {The journal of physical chemistry : C, Nanomaterials and interfaces}, volume = {116}, journal = {The journal of physical chemistry : C, Nanomaterials and interfaces}, number = {1}, publisher = {American Chemical Society}, address = {Washington}, issn = {1932-7447}, doi = {10.1021/jp206260r}, pages = {81 -- 85}, year = {2012}, abstract = {A facile one-pot synthesis for preparing thermosensitive, luminescent gold nanodots with diameters of 1-2 nm is presented. The influence of the alkyl chain length of the surface ligands (alkyl thiols) on the optical properties of the gold nanodots was investigated. The synthesized gold nanodots show strong thermosensitive photoluminescence. A photoluminescence quantum yield of 16.6\% was observed at room temperature, which could be improved to a value of 28.6\% when cooling the gold nanodot solutions to -7 degrees C. The synthesized thermosensitive, luminescent gold nanodots are interesting candidates for optoelectronic devices, medical imaging, sensing, or security labels.}, language = {en} } @article{BookhagenStrecker2012, author = {Bookhagen, Bodo and Strecker, Manfred}, title = {Spatiotemporal trends in erosion rates across a pronounced rainfall gradient: Examples from the southern Central Andes}, series = {Earth \& planetary science letters}, volume = {327}, journal = {Earth \& planetary science letters}, number = {8}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0012-821X}, doi = {10.1016/j.epsl.2012.02.005}, pages = {97 -- 110}, year = {2012}, abstract = {The tectonic and climatic boundary conditions of the broken foreland and the orogen interior of the southern Central Andes of northwestern Argentina cause strong contrasts in elevation, rainfall, and surface-process regimes. The climatic gradient in this region ranges from the wet, windward eastern flanks (similar to 2 m/yr rainfall) to progressively drier western basins and ranges (similar to 0.1 m/yr) bordering the arid Altiplano-Puna Plateau. In this study, we analyze the impact of spatiotemporal climatic gradients on surface erosion: First, we present 41 new catchment-mean erosion rates derived from cosmogenic nuclide inventories to document spatial erosion patterns. Second, we re-evaluate paleoclimatic records from the Calchaquies basin (66 W, 26 S), a large intermontane basin bordered by high (> 4.5 km) mountain ranges, to demonstrate temporal variations in erosion rates associated with changing climatic boundary conditions during the late Pleistocene and Holocene. Three key observations in this region emphasize the importance of climatic parameters on the efficiency of surface processes in space and time: (1) First-order spatial patterns of erosion rates can be explained by a simple specific stream power (SSP) approach. We explicitly account for discharge by routing high-resolution, satellite derived rainfall. This is important as the steep climatic gradient results in a highly non-linear relation between drainage area and discharge. This relation indicates that erosion rates (ER) scale with ER similar to SSP1.4 on cosmogenic-nuclide time scales. (2) We identify an intrinsic channel-slope behavior in different climatic compartments. Channel slopes in dry areas (< 0.25 m/yr rainfall) are slightly steeper than in wet areas (> 0.75 m/yr) with equal drainage areas, thus compensating lower amounts of discharge with steeper slopes. (3) Erosion rates can vary by an order of magnitude between presently dry (similar to 0.05 mm/yr) and well-defined late Pleistocene humid (similar to 0.5 mm/yr) conditions within an intemontane basin. Overall, we document a strong climatic impact on erosion rates and channel slopes. We suggest that rainfall reaching areas with steeper channel slopes in the orogen interior during wetter climate periods results in intensified sediment mass transport, which is primarily responsible for maintaining the balance between surface uplift, erosion, sediment routing and transient storage in the orogen.}, language = {en} } @article{BorchardtTrauth2012, author = {Borchardt, Sven and Trauth, Martin H.}, title = {Remotely-sensed evapotranspiration estimates for an improved hydrological modeling of the early holocene mega-lake Suguta, northern Kenya Rift}, series = {Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences}, volume = {361}, journal = {Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences}, number = {22}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0031-0182}, doi = {10.1016/j.palaeo.2012.07.009}, pages = {14 -- 20}, year = {2012}, abstract = {The actual evapotranspiration is an important, but difficult to determine, element in the water balance of lakes and their catchment areas. Reliable data on evapotranspiration are not available for most lake basins for which paleoclimate reconstructions and modeling have been performed, particularly those in remote parts of Africa. We have used thermal infrared multispectral data for 14 ASTER scenes from the TERRA satellite to estimate the actual evapotranspiration in the 12,800 km(2) catchment of the Suguta Valley, northern Kenya Rift Evidence from sediments and paleo-shorelines indicates that, during the African Humid Period (AHP, 14.8 to 5.5 kyrs BP), this valley contained a large lake, 280 m deep and covering similar to 2200 km(2), which has now virtually disappeared. Evapotranspiration estimates for the Suguta Basin were generated using the Surface Energy Balance Algorithm for Land (SEBAL). Climate data required for the model were extracted from a high-resolution gridded dataset obtained from the Climatic Research Unit (East Anglia, UK). Results suggest significant spatial variations in evapotranspiration within the catchment area (ranging from 450 mm/yr in the basin to the north to 2000 mm/yr in more elevated areas) and precipitation that was similar to 20\% higher during the AHP than in recent times. These results are in agreement with other estimates of paleo-precipitation in East Africa. The extreme response of the lake system (similar to 280 m greater water depth than today, and a lake surface area of 2200 km(2)) to only moderately higher precipitation illustrates the possible sensitivity of this area to future climate change.}, language = {en} } @article{BraeuerAschHofstetteretal.2012, author = {Braeuer, B. and Asch, G{\"u}nter and Hofstetter, Rami and Haberland, Christian and Jaser, Darweesh and El-Kelani, Radwan J.. and Weber, Michael H.}, title = {Microseismicity distribution in the southern Dead Sea basin and its implications on the structure of the basin}, series = {Geophysical journal international}, volume = {188}, journal = {Geophysical journal international}, number = {3}, publisher = {Wiley-Blackwell}, address = {Malden}, issn = {0956-540X}, doi = {10.1111/j.1365-246X.2011.05318.x}, pages = {873 -- 878}, year = {2012}, abstract = {While the Dead Sea basin has been studied for a long time, the available knowledge about the detailed seismicity distribution in the area, as well as the deeper structure of the basin, is limited. Therefore, within the framework of the international project DESIRE (DEad Sea Integrated REsearch project), a dense temporary local seismological network was operated in the southern Dead Sea area. We use 530 local earthquakes, having all together 26 730 P- and S-arrival times for a simultaneous inversion of 1-D velocity models, station corrections and precise earthquake locations. Jackknife tests suggest an accuracy of the derived hypocentre locations of about 1 km. Thus, the result is the first clear image of the absolute distribution of the microseismicity of the area, especially in depth. The seismicity is concentrated in the upper crust down to 20 km depth while the lower limit of the seismicity is reached at 31 km depth. The seismic events at the eastern boundary fault (EBF) in the southern part of the study area represent the northward transform motion of the Arabian Plate along the Dead Sea Transform. North of the Boqeq fault the seismic activity represents the transfer of the motion in the pull-apart basin from the eastern to the western boundary. We find that from the surface downward the seismic events are tracing the boundary faults of the basin. The western boundary is mapped down to 12 km depth while the EBF reaches about 17 km depth, forming an asymmetric basin. One fifth of the data set is related to a specific cluster in time and space, which occurred in 2007 February at the western border fault. This cluster is aligned vertically, that is, it is perpendicular to the direction of the dominating left-lateral strike-slip movement at the main transform fault.}, language = {en} } @article{BreitenbachRehfeldGoswamietal.2012, author = {Breitenbach, Sebastian Franz Martin and Rehfeld, Kira and Goswami, Bedartha and Baldini, James U. L. and Ridley, H. E. and Kennett, D. J. and Prufer, K. M. and Aquino, Valorie V. and Asmerom, Yemane and Polyak, V. J. and Cheng, Hai and Kurths, J{\"u}rgen and Marwan, Norbert}, title = {Constructing Proxy Records from Age models (COPRA)}, series = {Climate of the past : an interactive open access journal of the European Geosciences Union}, volume = {8}, journal = {Climate of the past : an interactive open access journal of the European Geosciences Union}, number = {5}, publisher = {Copernicus}, address = {G{\"o}ttingen}, issn = {1814-9324}, doi = {10.5194/cp-8-1765-2012}, pages = {1765 -- 1779}, year = {2012}, abstract = {Reliable age models are fundamental for any palaeoclimate reconstruction. Available interpolation procedures between age control points are often inadequately reported, and very few translate age uncertainties to proxy uncertainties. Most available modeling algorithms do not allow incorporation of layer counted intervals to improve the confidence limits of the age model in question. We present a framework that allows detection and interactive handling of age reversals and hiatuses, depth-age modeling, and proxy-record reconstruction. Monte Carlo simulation and a translation procedure are used to assign a precise time scale to climate proxies and to translate dating uncertainties to uncertainties in the proxy values. The presented framework allows integration of incremental relative dating information to improve the final age model. The free software package COPRA1.0 facilitates easy interactive usage.}, language = {en} } @article{BronstertCreutzfeldtGraeffetal.2012, author = {Bronstert, Axel and Creutzfeldt, Benjamin and Gr{\"a}ff, Thomas and Hajnsek, Irena and Heistermann, Maik and Itzerott, Sibylle and Jagdhuber, Thomas and Kneis, David and Lueck, Erika and Reusser, Dominik and Zehe, Erwin}, title = {Potentials and constraints of different types of soil moisture observations for flood simulations in headwater catchments}, series = {Natural hazards : journal of the International Society for the Prevention and Mitigation of Natural Hazards}, volume = {60}, journal = {Natural hazards : journal of the International Society for the Prevention and Mitigation of Natural Hazards}, number = {3}, publisher = {Springer}, address = {New York}, issn = {0921-030X}, doi = {10.1007/s11069-011-9874-9}, pages = {879 -- 914}, year = {2012}, abstract = {Flood generation in mountainous headwater catchments is governed by rainfall intensities, by the spatial distribution of rainfall and by the state of the catchment prior to the rainfall, e. g. by the spatial pattern of the soil moisture, groundwater conditions and possibly snow. The work presented here explores the limits and potentials of measuring soil moisture with different methods and in different scales and their potential use for flood simulation. These measurements were obtained in 2007 and 2008 within a comprehensive multi-scale experiment in the Weisseritz headwater catchment in the Ore-Mountains, Germany. The following technologies have been applied jointly thermogravimetric method, frequency domain reflectometry (FDR) sensors, spatial time domain reflectometry (STDR) cluster, ground-penetrating radar (GPR), airborne polarimetric synthetic aperture radar (polarimetric SAR) and advanced synthetic aperture radar (ASAR) based on the satellite Envisat. We present exemplary soil measurement results, with spatial scales ranging from point scale, via hillslope and field scale, to the catchment scale. Only the spatial TDR cluster was able to record continuous data. The other methods are limited to the date of over-flights (airplane and satellite) or measurement campaigns on the ground. For possible use in flood simulation, the observation of soil moisture at multiple scales has to be combined with suitable hydrological modelling, using the hydrological model WaSiM-ETH. Therefore, several simulation experiments have been conducted in order to test both the usability of the recorded soil moisture data and the suitability of a distributed hydrological model to make use of this information. The measurement results show that airborne-based and satellite-based systems in particular provide information on the near-surface spatial distribution. However, there are still a variety of limitations, such as the need for parallel ground measurements (Envisat ASAR), uncertainties in polarimetric decomposition techniques (polarimetric SAR), very limited information from remote sensing methods about vegetated surfaces and the non-availability of continuous measurements. The model experiments showed the importance of soil moisture as an initial condition for physically based flood modelling. However, the observed moisture data reflect the surface or near-surface soil moisture only. Hence, only saturated overland flow might be related to these data. Other flood generation processes influenced by catchment wetness in the subsurface such as subsurface storm flow or quick groundwater drainage cannot be assessed by these data. One has to acknowledge that, in spite of innovative measuring techniques on all spatial scales, soil moisture data for entire vegetated catchments are still today not operationally available. Therefore, observations of soil moisture should primarily be used to improve the quality of continuous, distributed hydrological catchment models that simulate the spatial distribution of moisture internally. Thus, when and where soil moisture data are available, they should be compared with their simulated equivalents in order to improve the parameter estimates and possibly the structure of the hydrological model.}, language = {en} } @article{BraeuerAschHofstetteretal.2012, author = {Br{\"a}uer, B. and Asch, G{\"u}nter and Hofstetter, Rami and Haberland, Christian and Jaser, D. and El-Kelani, R. and Weber, Michael H.}, title = {High-resolution local earthquake tomography of the southern Dead Sea area}, series = {Geophysical journal international}, volume = {191}, journal = {Geophysical journal international}, number = {3}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0956-540X}, doi = {10.1111/j.1365-246X.2012.05668.x}, pages = {881 -- 897}, year = {2012}, abstract = {Local earthquake data from a dense temporary seismological network in the southern Dead Sea area have been analysed within the project DESIRE (Dead Sea Integrated Research Project). Local earthquakes are used for the first precise image of the distribution of the P-wave velocity and the vP/vS ratios. 65 stations registered 655 local events within 18 months of observation time. A subset of 530 well-locatable events with 26 730 P- and S-arrival times was used to calculate a tomographic model for the vP and vP/vS distribution. Since the study area is at first-order 2-D, a gradual approach was chosen, which compromised a 2-D inversion followed by a 3-D inversion. The sedimentary basin fill is clearly imaged through high vP/vS ratios and low vP. The basin fill shows an asymmetric structure with average depth of 7 km at the western boundary and depth between 10 and 14 km at the eastern boundary. This asymmetry is reflected by the vertical strike-slip eastern border fault, and the normal faulting at the western boundary, caused by the transtensional deformation within the last 5 Myr. Within the basin fill the Lisan salt diapir is imaged through low vP/vS ratios, reflecting its low fluid content. The extensions were determined to 12 km in EW and 17 km in NS direction while its depth is 56 km. The thickness of the pre-basin sediments below the basin fill cannot be derived from the tomography datait is estimated to less than 3 km from former investigations. Below the basin, down to 18 km depth very low P-wave velocities and low vP/vS ratios are observedmost likely caused by fluids from the surrounding crust or the upper mantle.}, language = {en} } @article{BurkartWacoJosefssonDilkesetal.2012, author = {Burkart-Waco, Diana and Josefsson, Caroline and Dilkes, Brian and Kozloff, Nora and Torjek, Otto and Meyer, Rhonda C. and Altmann, Thomas and Comai, Luca}, title = {Hybrid incompatibility in arabidopsis is determined by a Multiple-Locus genetic network}, series = {Plant physiology : an international journal devoted to physiology, biochemistry, cellular and molecular biology, biophysics and environmental biology of plants}, volume = {158}, journal = {Plant physiology : an international journal devoted to physiology, biochemistry, cellular and molecular biology, biophysics and environmental biology of plants}, number = {2}, publisher = {American Society of Plant Physiologists}, address = {Rockville}, issn = {0032-0889}, doi = {10.1104/pp.111.188706}, pages = {801 -- 812}, year = {2012}, abstract = {The cross between Arabidopsis thaliana and the closely related species Arabidopsis arenosa results in postzygotic hybrid incompatibility, manifested as seed death. Ecotypes of A. thaliana were tested for their ability to produce live seed when crossed to A. arenosa. The identified genetic variation was used to map quantitative trait loci (QTLs) encoded by the A. thaliana genome that affect the frequency of postzygotic lethality and the phenotypes of surviving seeds. Seven QTLs affecting the A. thaliana component of this hybrid incompatibility were identified by crossing a Columbia x C24 recombinant inbred line population to diploid A. arenosa pollen donors. Additional epistatic loci were identified based on their pairwise interaction with one or several of these QTLs. Epistatic interactions were detected for all seven QTLs. The two largest additive QTLs were subjected to fine-mapping, indicating the action of at least two genes in each. The topology of this network reveals a large set of minor-effect loci from the maternal genome controlling hybrid growth and viability at different developmental stages. Our study establishes a framework that will enable the identification and characterization of genes and pathways in A. thaliana responsible for hybrid lethality in the A. thaliana x A. arenosa interspecific cross.}, language = {en} } @article{BaeseElsenbeerNeilletal.2012, author = {B{\"a}se, Frank and Elsenbeer, Helmut and Neill, Christopher and Krusche, Alex V.}, title = {Differences in throughfall and net precipitation between soybean and transitional tropical forest in the southern Amazon, Brazil}, series = {Agriculture, ecosystems \& environment : an international journal for scientific research on the relationship of agriculture and food production to the biosphere}, volume = {159}, journal = {Agriculture, ecosystems \& environment : an international journal for scientific research on the relationship of agriculture and food production to the biosphere}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0167-8809}, doi = {10.1016/j.agee.2012.06.013}, pages = {19 -- 28}, year = {2012}, abstract = {The expansion of soybean cultivation into the Amazon in Brazil has potential hydrological effects at local to regional scales. To determine the impacts of soybean agriculture on hydrology, a comparison of net precipitation (throughfall, stemflow) in undisturbed tropical forest and soybean fields on the southern edge of the Amazon Basin in the state of Mato Grosso is needed. This study measured throughfall with troughs and stemflow with collar collectors during two rainy seasons. The results showed that in forest 91.6\% of rainfall was collected as throughfall and 0.3\% as stemflow, while in soybean fields with two-month old plants, 46.2\% of rainfall was collected as throughfall and 9.0\% as stemflow. Hence, interception of precipitation in soybean fields was far greater than in intact forests. Differences in throughfall, stemflow and net precipitation were found to be mainly associated with differences in plant structure and stem density in transitional forest and soybean cropland. Because rainfall interception in soybean fields is higher than previously believed and because both the area of cropland and the frequency of crop cycles (double cropping) are increasing rapidly, interception needs to be reconsidered in regional water balance models when consequences of land cover changes are analyzed in the Amazon soybean frontier region. Based on the continued expansion of soybean fields across the landscape and the finding that net precipitation is lower in soy agriculture, a reduction in water availability in the long term can be assumed.}, language = {en} } @article{BoenigerTronicke2012, author = {B{\"o}niger, Urs and Tronicke, Jens}, title = {Subsurface utility extraction and characterization combining GPR symmetry and polarization attributes}, series = {IEEE transactions on geoscience and remote sensing}, volume = {50}, journal = {IEEE transactions on geoscience and remote sensing}, number = {3}, publisher = {Inst. of Electr. and Electronics Engineers}, address = {Piscataway}, issn = {0196-2892}, doi = {10.1109/TGRS.2011.2163413}, pages = {736 -- 746}, year = {2012}, abstract = {Polarization of the electromagnetic wavefield has significant implications for the acquisition and interpretation of ground-penetrating radar (GPR) data. Based on the geometrical and physical properties of the subsurface scatterer and the physical properties of its surrounding material, strong polarization phenomena might occur. Here, we develop an attribute-based analysis approach to extract and characterize buried utility pipes using two broadside antenna configurations. First, we enhance and extract the utilities by making use of their distinct symmetric nature through the application of a symmetry-enhancing image-processing algorithm known as phase symmetry. Second, we assess the polarization characteristics by calculating two attributes (polarization angle and linearity) using principal component analysis. Combination of attributes derived from these steps into a novel depolarization attribute allows one to efficiently detect and distinguish different utilities present within 3-D GPR data. The performance of our analysis approach is illustrated using synthetic examples and evaluated using field examples (including a dual-configuration 3-D data set) collected across a field site, where detailed ground-truth information is available. Our results demonstrate that the proposed approach allows for a more detailed extraction and combination of utility relevant information compared to approaches relying on single-component data and, thus, eases the interpretation of multicomponent GPR data sets.}, language = {en} } @article{CarrapaBywaterReyesDeCellesetal.2012, author = {Carrapa, Barbara and Bywater-Reyes, Sharon and DeCelles, Peter G. and Mortimer, Estelle and Gehrels, George E.}, title = {Late Eocene-Pliocene basin evolution in the Eastern Cordillera of northwestern Argentina (25 degrees-26 degrees S) regional implications for Andean orogenic wedge development}, series = {Basin research}, volume = {24}, journal = {Basin research}, number = {3}, publisher = {Wiley-Blackwell}, address = {Malden}, issn = {0950-091X}, doi = {10.1111/j.1365-2117.2011.00519.x}, pages = {249 -- 268}, year = {2012}, abstract = {Important aspects of the Andean foreland basin in Argentina remain poorly constrained, such as the effect of deformation on deposition, in which foreland basin depozones Cenozoic sedimentary units were deposited, how sediment sources and drainages evolved in response to tectonics, and the thickness of sediment accumulation. Zircon U-Pb geochronological data from EocenePliocene sedimentary strata in the Eastern Cordillera of northwestern Argentina (PucaraAngastaco and La Vina areas) provide an Eocene (ca.similar to 38 similar to Ma) maximum depositional age for the Quebrada de los Colorados Formation. Sedimentological and provenance data reveal a basin history that is best explained within the context of an evolving foreland basin system affected by inherited palaeotopography. The Quebrada de los Colorados Formation represents deposition in the distal to proximal foredeep depozone. Development of an angular unconformity at ca.similar to 14 similar to Ma and the coarse-grained, proximal character of the overlying Angastaco Formation (lower to upper Miocene) suggest deposition in a wedge-top depozone. Axial drainage during deposition of the Palo Pintado Formation (upper Miocene) suggests a fluvial-lacustrine intramontane setting. By ca.similar to 4 similar to Ma, during deposition of the San Felipe Formation, the Angastaco area had become structurally isolated by the uplift of the Sierra de los Colorados Range to the east. Overall, the Eastern Cordillera sedimentary record is consistent with a continuous foreland basin system that migrated through the region from late Eocene through middle Miocene time. By middle Miocene time, the region lay within the topographically complex wedge-top depozone, influenced by thick-skinned deformation and re-activation of Cretaceous rift structures. The association of the Eocene Quebrada del los Colorados Formation with a foredeep depozone implies that more distal foreland deposits should be represented by pre-Eocene strata (Santa Barbara Subgroup) within the region.}, language = {en} } @phdthesis{Chen2012, author = {Chen, Xiaoming}, title = {Two-dimensional constrained anisotropic inversion of magnetotelluric data}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-63163}, school = {Universit{\"a}t Potsdam}, year = {2012}, abstract = {Tectonic and geological processes on Earth often result in structural anisotropy of the subsurface, which can be imaged by various geophysical methods. In order to achieve appropriate and realistic Earth models for interpretation, inversion algorithms have to allow for an anisotropic subsurface. Within the framework of this thesis, I analyzed a magnetotelluric (MT) data set taken from the Cape Fold Belt in South Africa. This data set exhibited strong indications for crustal anisotropy, e.g. MT phases out of the expected quadrant, which are beyond of fitting and interpreting with standard isotropic inversion algorithms. To overcome this obstacle, I have developed a two-dimensional inversion method for reconstructing anisotropic electrical conductivity distributions. The MT inverse problem represents in general a non-linear and ill-posed minimization problem with many degrees of freedom: In isotropic case, we have to assign an electrical conductivity value to each cell of a large grid to assimilate the Earth's subsurface, e.g. a grid with 100 x 50 cells results in 5000 unknown model parameters in an isotropic case; in contrast, we have the sixfold in an anisotropic scenario where the single value of electrical conductivity becomes a symmetric, real-valued tensor while the number of the data remains unchanged. In order to successfully invert for anisotropic conductivities and to overcome the non-uniqueness of the solution of the inverse problem it is necessary to use appropriate constraints on the class of allowed models. This becomes even more important as MT data is not equally sensitive to all anisotropic parameters. In this thesis, I have developed an algorithm through which the solution of the anisotropic inversion problem is calculated by minimization of a global penalty functional consisting of three entries: the data misfit, the model roughness constraint and the anisotropy constraint. For comparison, in an isotropic approach only the first two entries are minimized. The newly defined anisotropy term is measured by the sum of the square difference of the principal conductivity values of the model. The basic idea of this constraint is straightforward. If an isotropic model is already adequate to explain the data, there is no need to introduce electrical anisotropy at all. In order to ensure successful inversion, appropriate trade-off parameters, also known as regularization parameters, have to be chosen for the different model constraints. Synthetic tests show that using fixed trade-off parameters usually causes the inversion to end up by either a smooth model with large RMS error or a rough model with small RMS error. Using of a relaxation approach on the regularization parameters after each successful inversion iteration will result in smoother inversion model and a better convergence. This approach seems to be a sophisticated way for the selection of trade-off parameters. In general, the proposed inversion method is adequate for resolving the principal conductivities defined in horizontal plane. Once none of the principal directions of the anisotropic structure is coincided with the predefined strike direction, only the corresponding effective conductivities, which is the projection of the principal conductivities onto the model coordinate axes direction, can be resolved and the information about the rotation angles is lost. In the end the MT data from the Cape Fold Belt in South Africa has been analyzed. The MT data exhibits an area (> 10 km) where MT phases over 90 degrees occur. This part of data cannot be modeled by standard isotropic modeling procedures and hence can not be properly interpreted. The proposed inversion method, however, could not reproduce the anomalous large phases as desired because of losing the information about rotation angles. MT phases outside the first quadrant are usually obtained by different anisotropic anomalies with oblique anisotropy strike. In order to achieve this challenge, the algorithm needs further developments. However, forward modeling studies with the MT data have shown that surface highly conductive heterogeneity in combination with a mid-crustal electrically anisotropic zone are required to fit the data. According to known geological and tectonic information the mid-crustal zone is interpreted as a deep aquifer related to the fractured Table Mountain Group rocks in the Cape Fold Belt.}, language = {en} } @article{ChristImmenhauserAmouretal.2012, author = {Christ, Nicolas and Immenhauser, Adrian and Amour, Frederic and Mutti, Maria and Preston, Rosalind and Whitaker, Fiona F. and Peterh{\"a}nsel, Arndt and Egenhoff, Sven O. and Dunn, Paul A. and Agar, Susan M.}, title = {Triassic Latemar cycle tops - Subaerial exposure of platform carbonates under tropical arid climate}, series = {Sedimentary geology : international journal of applied and regional sedimentology}, volume = {265}, journal = {Sedimentary geology : international journal of applied and regional sedimentology}, number = {28}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0037-0738}, doi = {10.1016/j.sedgeo.2012.02.008}, pages = {1 -- 29}, year = {2012}, abstract = {The Triassic Latemar platform in the Dolomites, Italy, is the site of several ongoing controversies. Perhaps the most interesting debate focuses on apparent cyclic deposition within the Latemar platform, whose nature and duration are still open to debate. Further disagreement concerns the lack of meteoric diagenesis-related isotope shifts at cycle tops that bear circumstantial petrographic evidence for subaerial emergence. Here, an evaluation of the nature of Latemar cycle tops is presented combining evidence from previous work and new field, petrographic and geochemical data. Cycle tops are ranked according to increasing exposure duration and spatial extent: type I surfaces lacking unequivocal evidence of prolonged supratidal conditions; type II dolomite caps formed in warm, evaporitic, intertidal lagoonal waters followed by exposure of perhaps intermediate duration; type III clastic-rich, red calcareous horizons with some showing platform-wide extent, representing prolonged supratidal conditions, and type IV discontinuities in tepee belts, genetically related to type II and III surfaces, but likely representing shorter-lived exposure stages. Petrographic and geochemical criteria indicate that most diagenesis occurred in the shallow marine and burial domain whilst an extensive meteoric overprint of cycle tops is lacking. This is underlined by the scarcity of meteoric diagenetic fabrics such as gravitational cements that, where present, are here interpreted as marine-vadose in origin. The scarcity of carbon and oxygen isotope signatures commonly assigned to subaerial exposure stages is best explained in the context of mid-Triassic climate. The low latitude, tropical but arid setting of the Latemar, situated in the western extension of the Tethys ocean, its isolation from nearby continental areas and overall short-term emergence episodes are in agreement with a limited degree of meteoric alteration of most cycle tops. High amounts of aeolian clastic material beneath some cycle tops, along with high Fe and Mn elemental abundances argue for intermittent subaerial conditions. This study proposes an enhancement of the classical Allan and Matthews (1982) isotope model for subaerial exposure under strongly arid climates. As the subaerial exposure nature of Latemar cycle tops, and therefore eustasy as the cause for cyclicity, have been previously challenged due to the lack of meteoric-induced isotopic signatures, the outcome of this study is of significance for the ongoing Latemar stratigraphic controversy.}, language = {en} } @article{ChristImmenhauserAmouretal.2012, author = {Christ, Nicolas and Immenhauser, Adrian and Amour, Frederic and Mutti, Maria and Tomas, Sara and Agar, Susan M. and Alway, Robert and Kabiri, Lahcen}, title = {Characterization and interpretation of discontinuity surfaces in a Jurassic ramp setting (High Atlas, Morocco)}, series = {Sedimentology : the journal of the International Association of Sedimentologists}, volume = {59}, journal = {Sedimentology : the journal of the International Association of Sedimentologists}, number = {1}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0037-0746}, doi = {10.1111/j.1365-3091.2011.01251.x}, pages = {249 -- 290}, year = {2012}, abstract = {Discontinuity surfaces are widely recognized but often poorly understood features of epeiric carbonate settings. In sedimentary systems, these features often represent hiatus surfaces below biostratigraphic resolution and may represent a considerable portion of the time contained in the sediment record. From an applied perspective, discontinuities may represent horizontal flow barriers and result in reservoir compartmentalization. Here, a total of 80 condensed surfaces (S1), firmgrounds (S2) and hardgrounds (S3) from a Jurassic (Middle and Upper Bajocian Assoul Formation) ramp setting of the High Atlas in Morocco are carefully documented with respect to their morphology, their secondary impregnation by Fe and Mn oxides and phosphates and their palaeoecological record. A statistical frequency distribution of two surfaces of the S1 type, 1.1 surfaces of the S2 type and 0.4 surfaces of the S3 type per 10 section metres is observed along a 220 m long carbonate succession. Based on two stratigraphically and spatially separated study windows and correlative sections, the stratigraphic frequency distribution, the lateral extent and the nature of facies change across discontinuities are documented in a quantitative manner. Specific features of the study site include the considerable stratigraphic thickness of the Assoul Formation and the conspicuous absence of subaerial-exposure-related features. Based on the data presented here, firmground and hardground surfaces are best interpreted as maximum-regression-related features. Relative sea-level lowstand results in a lowered wave base, and wave orbitals and currents result in sea floor omission and lithification. Care must be taken to avoid overly simplistic interpretations, as differences in bathymetry and carbonate facies result in marked changes in discontinuity characteristics in proximal-distal transects. The data shown here are of significance for those concerned with the interpretation of shoal water carbonate environments and are instrumental in the building of more realistic carbonate reservoir flow models.}, language = {en} } @article{CiobanuRabineauDrozetal.2012, author = {Ciobanu, M. -C. and Rabineau, M. and Droz, L. and Revillon, S. and Ghiglione, J. -F. and Dennielou, B. and Jorry, S. -J. and Kallmeyer, Jens and Etoubleau, J. and Pignet, P. and Crassous, P. and Vandenabeele-Trambouze, O. and Laugier, J. and Guegan, M. and Godfroy, A. and Alain, K.}, title = {Sedimentological imprint on subseafloor microbial communities in Western Mediterranean Sea Quaternary sediments}, series = {Biogeosciences}, volume = {9}, journal = {Biogeosciences}, number = {9}, publisher = {Copernicus}, address = {G{\"o}ttingen}, issn = {1726-4170}, doi = {10.5194/bg-9-3491-2012}, pages = {3491 -- 3512}, year = {2012}, abstract = {An interdisciplinary study was conducted to evaluate the relationship between geological and paleoenvironmental parameters and the bacterial and archaeal community structure of two contrasting subseafloor sites in the Western Mediterranean Sea (Ligurian Sea and Gulf of Lion). Both depositional environments in this area are well-documented from paleoclimatic and paleooceanographic point of views. Available data sets allowed us to calibrate the investigated cores with reference and dated cores previously collected in the same area, and notably correlated to Quaternary climate variations. DNA-based fingerprints showed that the archaeal diversity was composed by one group, Miscellaneous Crenarchaeotic Group (MCG), within the Gulf of Lion sediments and of nine different lineages (dominated by MCG, South African Gold Mine Euryarchaeotal Group (SAGMEG) and Halobacteria) within the Ligurian Sea sediments. Bacterial molecular diversity at both sites revealed mostly the presence of the classes Alphaproteobacteria, Betaproteobacteria and Gammaproteobacteria within Proteobacteria phylum, and also members of Bacteroidetes phylum. The second most abundant lineages were Actinobacteria and Firmicutes at the Gulf of Lion site and Chloroflexi at the Ligurian Sea site. Various substrates and cultivation conditions allowed us to isolate 75 strains belonging to four lineages: Alpha-, Gammaproteobacteria, Firmicutes and Actinobacteria. In molecular surveys, the Betaproteobacteria group was consistently detected in the Ligurian Sea sediments, characterized by a heterolithic facies with numerous turbidites from a deep-sea levee. Analysis of relative betaproteobacterial abundances and turbidite frequency suggested that the microbial diversity was a result of main climatic changes occurring during the last 20 ka. Statistical direct multivariate canonical correspondence analyses (CCA) showed that the availability of electron acceptors and the quality of electron donors (indicated by age) strongly influenced the community structure. In contrast, within the Gulf of Lion core, characterized by a homogeneous lithological structure of upper-slope environment, most detected groups were Bacteroidetes and, to a lesser extent, Betaproteobacteria. At both site, the detection of Betaproteobacteria coincided with increased terrestrial inputs, as confirmed by the geochemical measurements (Si, Sr, Ti and Ca). In the Gulf of Lion, geochemical parameters were also found to drive microbial community composition. Taken together, our data suggest that the palaeoenvironmental history of erosion and deposition recorded in the Western Mediterranean Sea sediments has left its imprint on the sedimentological context for microbial habitability, and then indirectly on structure and composition of the microbial communities during the late Quaternary.}, language = {en} } @article{CockellVoytekGronstaletal.2012, author = {Cockell, Charles S. and Voytek, Mary A. and Gronstal, Aaron L. and Finster, Kai and Kirshtein, Julie D. and Howard, Kieren and Reitner, Joachim and Gohn, Gregory S. and Sanford, Ward E. and Horton, J. Wright and Kallmeyer, Jens and Kelly, Laura and Powars, David S.}, title = {Impact disruption and recovery of the deep subsurface biosphere}, series = {Astrobiology}, volume = {12}, journal = {Astrobiology}, number = {3}, publisher = {Liebert}, address = {New Rochelle}, issn = {1531-1074}, doi = {10.1089/ast.2011.0722}, pages = {231 -- 246}, year = {2012}, abstract = {Although a large fraction of the world's biomass resides in the subsurface, there has been no study of the effects of catastrophic disturbance on the deep biosphere and the rate of its subsequent recovery. We carried out an investigation of the microbiology of a 1.76 km drill core obtained from the similar to 35 million-year-old Chesapeake Bay impact structure, USA, with robust contamination control. Microbial enumerations displayed a logarithmic downward decline, but the different gradient, when compared to previously studied sites, and the scatter of the data are consistent with a rnicrobiota influenced by the geological disturbances caused by the impact. Microbial abundance is low in buried crater-fill, ocean-resurge, and avalanche deposits despite the presence of redox couples for growth. Coupled with the low hydraulic conductivity, the data suggest the microbial community has not yet recovered from the impact similar to 35 million years ago. Microbial enumerations, molecular analysis of microbial enrichment cultures, and geochemical analysis showed recolonization of a deep region of impact-fractured rock that was heated to above the upper temperature limit for life at the time of impact. These results show how, by fracturing subsurface rocks, impacts can extend the depth of the biosphere. This phenomenon would have provided deep refugia for life on the more heavily bombarded early Earth, and it shows that the deeply fractured regions of impact craters are promising targets to study the past and present habitability of Mars.}, language = {en} } @article{CollingsLangeRietbrocketal.2012, author = {Collings, R. and Lange, Dietrich and Rietbrock, Andreas and Tilmann, F. and Natawidjaja, D. and Suwargadi, B. and Miller, M. and Saul, Joschim}, title = {Structure and seismogenic properties of the Mentawai segment of the Sumatra subduction zone revealed by local earthquake traveltime tomography}, series = {Journal of geophysical research : Solid earth}, volume = {117}, journal = {Journal of geophysical research : Solid earth}, number = {3}, publisher = {American Geophysical Union}, address = {Washington}, issn = {2169-9313}, doi = {10.1029/2011JB008469}, pages = {23}, year = {2012}, abstract = {On 12 September 2007, an M-w 8.4 earthquake occurred within the southern section of the Mentawai segment of the Sumatra subduction zone, where the subduction thrust had previously ruptured in 1833 and 1797. Traveltime data obtained from a temporary local seismic network, deployed between December 2007 and October 2008 to record the aftershocks of the 2007 event, was used to determine two-dimensional (2-D) and three-dimensional (3-D) velocity models of the Mentawai segment. The seismicity distribution reveals significant activity along the subduction interface and within two clusters in the overriding plate either side of the forearc basin. The downgoing slab is clearly distinguished by a dipping region of high Vp (8.0 km/s), which can be a traced to similar to 50 km depth, with an increased Vp/Vs ratio (1.75 to 1.90) beneath the islands and the western side of the forearc basin, suggesting hydrated oceanic crust. Above the slab, a shallow continental Moho of less than 30 km depth can be inferred, suggesting that the intersection of the continental mantle with the subducting slab is much shallower than the downdip limit of the seismogenic zone despite localized serpentinization being present at the toe of the mantle wedge. The outer arc islands are characterized by low Vp (4.5-5.8 km/s) and high Vp/Vs (greater than 2.0), suggesting that they consist of fluid saturated sediments. The very low rigidity of the outer forearc contributed to the slow rupture of the M-w 7.7 Mentawai tsunami earthquake on 25 October 2010.}, language = {en} } @article{CosentinoSchildgenCipollarietal.2012, author = {Cosentino, Domenico and Schildgen, Taylor F. and Cipollari, Paola and Faranda, Costanza and Gliozzi, Elsa and Hudackova, Natalia and Lucifora, Stella and Strecker, Manfred}, title = {Late Miocene surface uplift of the southern margin of the Central Anatolian Plateau, Central Taurides, Turkey}, series = {Geological Society of America bulletin}, volume = {124}, journal = {Geological Society of America bulletin}, number = {1-2}, publisher = {American Institute of Physics}, address = {Boulder}, issn = {0016-7606}, doi = {10.1130/B30466.1}, pages = {133 -- 145}, year = {2012}, abstract = {The timing and pattern of surface uplift of Miocene marine sediments capping the southern margin of the Central Anatolian Plateau in southern Turkey provide a first-order constraint on possible mechanisms of regional uplift. Nannofossil, ostracod, and planktic foraminifera biostratigraphy of the Basyayla section (Mut-Ermenek Basin) within the Mut and Kfiselerli Formations suggests a Tortonian age for marine sediments unconformably capping basement rocks at 2 km elevation. The identification of biozone MMi 12a (7.81-8.35 Ma) from planktic foraminifera in the upper part of the section provides the tightest constraint on the age, which is further limited to 8.35-8.108 Ma as a result of the reverse polarity of the collected samples (chron 4r.1 r or 4r.2r). This provides a limiting age for the onset of surface uplift at the margin of one of the world's major orogenic plateaus, from which an average uplift rate of 0.24-0.25 mm/yr can be calculated. Subhorizontal beds of the uppermost marine sediments exposed throughout the Mut-Ermenek Basin suggest minimal localized deformation, with just minor faulting at the basin margin and broad antiformal deformation across the basin. This implies that the post-8 Ma uplift mechanism must be rooted deep within the crust or in the upper mantle. Published Pn-wave velocity data for the region are compatible with topography compensated by asthenosphere across the southern margin of the plateau, showing a close match to the highest topography when elevations are filtered with a 100-km-wide smoothing window. Uplift along the southern margin of the Central Anatolian Plateau is also reflected by the pattern of Miocene marine sediments capping the margin, which form an asymmetric drape fold over the topography. These observations, together with tomographic evidence for slab steepening and break-off beneath the Eastern Anatolian Plateau, suggest that at least some of the 2 km of post-8 Ma uplift of the southern Central Anatolian Plateau margin is compensated by low-density asthenospheric mantle that upwelled following slab break-off.}, language = {en} } @article{CostaBronstertKneis2012, author = {Costa, Alexandre Cunha and Bronstert, Axel and Kneis, David}, title = {Probabilistic flood forecasting for a mountainous headwater catchment using a nonparametric stochastic dynamic approach}, series = {Hydrological sciences journal = Journal des sciences hydrologiques}, volume = {57}, journal = {Hydrological sciences journal = Journal des sciences hydrologiques}, number = {1}, publisher = {Routledge, Taylor \& Francis Group}, address = {Abingdon}, issn = {0262-6667}, doi = {10.1080/02626667.2011.637043}, pages = {10 -- 25}, year = {2012}, abstract = {Hydrological models are commonly used to perform real-time runoff forecasting for flood warning. Their application requires catchment characteristics and precipitation series that are not always available. An alternative approach is nonparametric modelling based only on runoff series. However, the following questions arise: Can nonparametric models show reliable forecasting? Can they perform as reliably as hydrological models? We performed probabilistic forecasting one, two and three hours ahead for a runoff series, with the aim of ascribing a probability density function to predicted discharge using time series analysis based on stochastic dynamics theory. The derived dynamic terms were compared to a hydrological model, LARSIM. Our procedure was able to forecast within 95\% confidence interval 1-, 2- and 3-h ahead discharge probability functions with about 1.40 m(3)/s of range and relative errors (\%) in the range [-30; 30]. The LARSIM model and the best nonparametric approaches gave similar results, but the range of relative errors was larger for the nonparametric approaches.}, language = {en} } @phdthesis{CunhaCosta2012, author = {Cunha Costa, Alexandre}, title = {Analyzing and modelling of flow transmission processes in river-systems with a focus on semi-arid conditions}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-59694}, school = {Universit{\"a}t Potsdam}, year = {2012}, abstract = {One of the major problems for the implementation of water resources planning and management in arid and semi-arid environments is the scarcity of hydrological data and, consequently, research studies. In this thesis, the hydrology of dryland river systems was analyzed and a semi-distributed hydrological model and a forecasting approach were developed for flow transmission processes in river-systems with a focus on semi-arid conditions. Three different sources of hydrological data (streamflow series, groundwater level series and multi-temporal satellite data) were combined in order to analyze the channel transmission losses of a large reach of the Jaguaribe River in NE Brazil. A perceptual model of this reach was derived suggesting that the application of models, which were developed for sub-humid and temperate regions, may be more suitable for this reach than classical models, which were developed for arid and semi-arid regions. Summarily, it was shown that this river reach is hydraulically connected with groundwater and shifts from being a losing river at the dry and beginning of rainy seasons to become a losing/gaining (mostly losing) river at the middle and end of rainy seasons. A new semi-distributed channel transmission losses model was developed, which was based primarily on the capability of simulation in very different dryland environments and flexible model structures for testing hypotheses on the dominant hydrological processes of rivers. This model was successfully tested in a large reach of the Jaguaribe River in NE Brazil and a small stream in the Walnut Gulch Experimental Watershed in the SW USA. Hypotheses on the dominant processes of the channel transmission losses (different model structures) in the Jaguaribe river were evaluated, showing that both lateral (stream-)aquifer water fluxes and ground-water flow in the underlying alluvium parallel to the river course are necessary to predict streamflow and channel transmission losses, the former process being more relevant than the latter. This procedure not only reduced model structure uncertainties, but also reported modelling failures rejecting model structure hypotheses, namely streamflow without river-aquifer interaction and stream-aquifer flow without groundwater flow parallel to the river course. The application of the model to different dryland environments enabled learning about the model itself from differences in channel reach responses. For example, the parameters related to the unsaturated part of the model, which were active for the small reach in the USA, presented a much greater variation in the sensitivity coefficients than those which drove the saturated part of the model, which were active for the large reach in Brazil. Moreover, a nonparametric approach, which dealt with both deterministic evolution and inherent fluctuations in river discharge data, was developed based on a qualitative dynamical system-based criterion, which involved a learning process about the structure of the time series, instead of a fitting procedure only. This approach, which was based only on the discharge time series itself, was applied to a headwater catchment in Germany, in which runoff are induced by either convective rainfall during the summer or snow melt in the spring. The application showed the following important features: • the differences between runoff measurements were more suitable than the actual runoff measurements when using regression models; • the catchment runoff system shifted from being a possible dynamical system contaminated with noise to a linear random process when the interval time of the discharge time series increased; • and runoff underestimation can be expected for rising limbs and overestimation for falling limbs. This nonparametric approach was compared with a distributed hydrological model designed for real-time flood forecasting, with both presenting similar results on average. Finally, a benchmark for hydrological research using semi-distributed modelling was proposed, based on the aforementioned analysis, modelling and forecasting of flow transmission processes. The aim of this benchmark was not to describe a blue-print for hydrological modelling design, but rather to propose a scientific method to improve hydrological knowledge using semi-distributed hydrological modelling. Following the application of the proposed benchmark to a case study, the actual state of its hydrological knowledge and its predictive uncertainty can be determined, primarily through rejected hypotheses on the dominant hydrological processes and differences in catchment/variables responses.}, language = {en} } @phdthesis{Czymzik2012, author = {Czymzik, Markus}, title = {Mid- to Late Holocene flood reconstruction from two varved sediment profiles of pre-alpine Lake Ammersee (Southern Germany)}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-65098}, school = {Universit{\"a}t Potsdam}, year = {2012}, abstract = {Climate is the principal driving force of hydrological extremes like floods and attributing generating mechanisms is an essential prerequisite for understanding past, present, and future flood variability. Successively enhanced radiative forcing under global warming enhances atmospheric water-holding capacity and is expected to increase the likelihood of strong floods. In addition, natural climate variability affects the frequency and magnitude of these events on annual to millennial time-scales. Particularly in the mid-latitudes of the Northern Hemisphere, correlations between meteorological variables and hydrological indices suggest significant effects of changing climate boundary conditions on floods. To date, however, understanding of flood responses to changing climate boundary conditions is limited due to the scarcity of hydrological data in space and time. Exploring paleoclimate archives like annually laminated (varved) lake sediments allows to fill this gap in knowledge offering precise dated time-series of flood variability for millennia. During river floods, detrital catchment material is eroded and transported in suspension by fluid turbulence into downstream lakes. In the water body the transport capacity of the inflowing turbidity current successively diminishes leading to the deposition of detrital layers on the lake floor. Intercalated into annual laminations these detrital layers can be dated down to seasonal resolution. Microfacies analyses and X-ray fluorescence scanning (µ-XRF) at 200 µm resolution were conducted on the varved Mid- to Late Holocene interval of two sediment profiles from pre-alpine Lake Ammersee (southern Germany) located in a proximal (AS10prox) and distal (AS10dist) position towards the main tributary River Ammer. To shed light on sediment distribution within the lake, particular emphasis was (1) the detection of intercalated detrital layers and their micro-sedimentological features, and (2) intra-basin correlation of these deposits. Detrital layers were dated down to the season by microscopic varve counting and determination of the microstratigraphic position within a varve. The resulting chronology is verified by accelerator mass spectrometry (AMS) 14C dating of 14 terrestrial plant macrofossils. Since ~5500 varve years before present (vyr BP), in total 1573 detrital layers were detected in either one or both of the investigated sediment profiles. Based on their microfacies, geochemistry, and proximal-distal deposition pattern, detrital layers were interpreted as River Ammer flood deposits. Calibration of the flood layer record using instrumental daily River Ammer runoff data from AD 1926 to 1999 proves the flood layer succession to represent a significant time-series of major River Ammer floods in spring and summer, the flood season in the Ammersee region. Flood layer frequency trends are in agreement with decadal variations of the East Atlantic-Western Russia (EA-WR) atmospheric pattern back to 200 yr BP (end of the used atmospheric data) and solar activity back to 5500 vyr BP. Enhanced flood frequency corresponds to the negative EA-WR phase and reduced solar activity. These common links point to a central role of varying large-scale atmospheric circulation over Europe for flood frequency in the Ammersee region and suggest that these atmospheric variations, in turn, are likely modified by solar variability during the past 5500 years. Furthermore, the flood layer record indicates three shifts in mean layer thickness and frequency of different manifestation in both sediment profiles at ~5500, ~2800, and ~500 vyr BP. Combining information from both sediment profiles enabled to interpret these shifts in terms of stepwise increases in mean flood intensity. Likely triggers of these shifts are gradual reduction of Northern Hemisphere orbital summer forcing and long-term solar activity minima. Hypothesized atmospheric response to this forcing is hemispheric cooling that enhances equator-to-pole temperature gradients and potential energy in the troposphere. This energy is transferred into stronger westerly cyclones, more extreme precipitation, and intensified floods at Lake Ammersee. Interpretation of flood layer frequency and thickness data in combination with reanalysis models and time-series analysis allowed to reconstruct the flood history and to decipher flood triggering climate mechanisms in the Ammersee region throughout the past 5500 years. Flood frequency and intensity are not stationary, but influenced by multi-causal climate forcing of large-scale atmospheric modes on time-scales from years to millennia. These results challenge future projections that propose an increase in floods when Earth warms based only on the assumption of an enhanced hydrological cycle.}, language = {en} } @article{DeBiaseMaierBaederBederskietal.2012, author = {De Biase, Cecilia and Maier, Uli and Baeder-Bederski, Oliver and Bayer, Peter and Oswald, Sascha and Thullner, Martin}, title = {Removal of volatile organic compounds in vertical flow filters - predictions from reactive transport modeling}, series = {Ground water monitoring \& remediation}, volume = {32}, journal = {Ground water monitoring \& remediation}, number = {2}, publisher = {Wiley-Blackwell}, address = {Malden}, issn = {1069-3629}, doi = {10.1111/j.1745-6592.2011.01374.x}, pages = {106 -- 121}, year = {2012}, abstract = {Vertical flow filters are containers filled with porous medium that are recharged from top and drained at the bottom, and are operated at partly saturated conditions. They have recently been suggested as treatment technology for groundwater containing volatile organic compounds (VOCs). Numerical reactive transport simulations were performed to investigate the relevance of different filter operation modes on biodegradation and/or volatilization of the contaminants and to evaluate the potential limitation of such remediation mean due to volatile emissions. On the basis of the data from a pilot-scale vertical flow filter intermittently fed with domestic waste water, model predictions on the systems performance for the treatment of contaminated groundwater were derived. These simulations considered the transport and aerobic degradation of ammonium and two VOCs, benzene and methyl tertiary butyl ether (MTBE). In addition, the advective-diffusive gas-phase transport of volatile compounds as well as oxygen was simulated. Model predictions addressed the influence of depth and frequency of the intermittent groundwater injection, degradation rate kinetics, and the composition of the filter material. Simulation results show that for unfavorable operation conditions significant VOC emissions have to be considered and that operation modes limiting VOC emissions may limit aerobic biodegradation. However, a suitable combination of injection depth and composition of the filter material does facilitate high biodegradation rates while only little VOC emissions take place. Using such optimized operation modes would allow using vertical flow filter systems as remediation technology suitable for groundwater contaminated with volatile compounds.}, language = {en} } @article{DebatinBehrensWeberetal.2012, author = {Debatin, Franziska and Behrens, Karsten and Weber, Jens and Baburin, Igor A. and Thomas, Arne and Schmidt, Johannes and Senkovska, Irena and Kaskel, Stefan and Kelling, Alexandra and Hedin, Niklas and Bacsik, Zoltan and Leoni, Stefano and Seifert, Gotthard and J{\"a}ger, Christian and G{\"u}nter, Christina and Schilde, Uwe and Friedrich, Alwin and Holdt, Hans-J{\"u}rgen}, title = {An isoreticular family of microporous metal-organic frameworks based on zinc and 2-substituted imidazolate-4-amide-5-imidate Syntheses, structures and properties}, series = {Chemistry - a European journal}, volume = {18}, journal = {Chemistry - a European journal}, number = {37}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0947-6539}, doi = {10.1002/chem.201200889}, pages = {11630 -- 11640}, year = {2012}, abstract = {We report on a new series of isoreticular frameworks based on zinc and 2-substituted imidazolate-4-amide-5-imidate (IFP-14, IFP=imidazolate framework Potsdam) that form one-dimensional, microporous hexagonal channels. Varying R in the 2-substitued linker (R=Me (IFP-1), Cl (IFP-2), Br (IFP-3), Et (IFP-4)) allowed the channel diameter (4.01.7 angstrom), the polarisability and functionality of the channel walls to be tuned. Frameworks IFP-2, IFP-3 and IFP-4 are isostructural to previously reported IFP-1. The structures of IFP-2 and IFP-3 were solved by X-ray crystallographic analyses. The structure of IFP-4 was determined by a combination of PXRD and structure modelling and was confirmed by IR spectroscopy and 1H MAS and 13C CP-MAS NMR spectroscopy. All IFPs showed high thermal stability (345400?degrees C); IFP-1 and IFP-4 were stable in boiling water for 7 d. A detailed porosity analysis was performed on the basis of adsorption measurements by using various gases. The potential of the materials to undergo specific interactions with CO2 was investigated by measuring the isosteric heats of adsorption. The capacity to adsorb CH4 (at 298 K), CO2 (at 298 K) and H2 (at 77 K) at high pressure were also investigated. In situ IR spectroscopy showed that CO2 is physisorbed on IFP-14 under dry conditions and that both CO2 and H2O are physisorbed on IFP-1 under moist conditions.}, language = {en} } @article{DelavaudCottonAkkaretal.2012, author = {Delavaud, Elise and Cotton, Fabrice and Akkar, Sinan and Scherbaum, Frank and Danciu, Laurentiu and Beauval, Celine and Drouet, Stephane and Douglas, John and Basili, Roberto and Sandikkaya, M. Abdullah and Segou, Margaret and Faccioli, Ezio and Theodoulidis, Nikos}, title = {Toward a ground-motion logic tree for probabilistic seismic hazard assessment in Europe}, series = {Journal of seismology}, volume = {16}, journal = {Journal of seismology}, number = {3}, publisher = {Springer}, address = {Dordrecht}, issn = {1383-4649}, doi = {10.1007/s10950-012-9281-z}, pages = {451 -- 473}, year = {2012}, abstract = {The Seismic Hazard Harmonization in Europe (SHARE) project, which began in June 2009, aims at establishing new standards for probabilistic seismic hazard assessment in the Euro-Mediterranean region. In this context, a logic tree for ground-motion prediction in Europe has been constructed. Ground-motion prediction equations (GMPEs) and weights have been determined so that the logic tree captures epistemic uncertainty in ground-motion prediction for six different tectonic regimes in Europe. Here we present the strategy that we adopted to build such a logic tree. This strategy has the particularity of combining two complementary and independent approaches: expert judgment and data testing. A set of six experts was asked to weight pre-selected GMPEs while the ability of these GMPEs to predict available data was evaluated with the method of Scherbaum et al. (Bull Seismol Soc Am 99:3234-3247, 2009). Results of both approaches were taken into account to commonly select the smallest set of GMPEs to capture the uncertainty in ground-motion prediction in Europe. For stable continental regions, two models, both from eastern North America, have been selected for shields, and three GMPEs from active shallow crustal regions have been added for continental crust. For subduction zones, four models, all non-European, have been chosen. Finally, for active shallow crustal regions, we selected four models, each of them from a different host region but only two of them were kept for long periods. In most cases, a common agreement has been also reached for the weights. In case of divergence, a sensitivity analysis of the weights on the seismic hazard has been conducted, showing that once the GMPEs have been selected, the associated set of weights has a smaller influence on the hazard.}, language = {en} } @article{DelavaudScherbaumKuehnetal.2012, author = {Delavaud, Elise and Scherbaum, Frank and K{\"u}hn, Nicolas and Allen, Trevor}, title = {Testing the global applicability of ground-motion prediction equations for active shallow crustal regions}, series = {Bulletin of the Seismological Society of America}, volume = {102}, journal = {Bulletin of the Seismological Society of America}, number = {2}, publisher = {Seismological Society of America}, address = {El Cerrito}, issn = {0037-1106}, doi = {10.1785/0120110113}, pages = {707 -- 721}, year = {2012}, abstract = {Large research initiatives such as the Global Earthquake Model (GEM) or the Seismic HAzard haRmonization in Europe (SHARE) projects concentrate a great collaborative effort on defining a global standard for seismic hazard estimations. In this context, there is an increasing need for identifying ground-motion prediction equations (GMPEs) that can be applied at both global and regional scale. With increasing amounts of strong-motion records that are now available worldwide, observational data can provide a valuable resource to tackle this question. Using the global dataset of Allen and Wald (2009), we evaluate the ability of 11 GMPEs to predict ground-motion in different active shallow crustal regions worldwide. Adopting the approach of Scherbaum et al. (2009), we rank these GMPEs according to their likelihood of having generated the data. In particular, we estimate how strongly data support or reject the models with respect to the state of noninformativeness defined by a uniform weighting. Such rankings derived from this particular global dataset enable us to explore the potential of GMPEs to predict ground motions in their host region and also in other regions depending on the magnitude and distance considered. In the ranking process, we particularly focus on the influence of the distribution of the testing dataset compared with the GMPE's native dataset. One of the results of this study is that some nonindigenous models present a high degree of consistency with the data from a target region. Two models in particular demonstrated a strong power of geographically wide applicability in different geographic regions with respect to the testing dataset: the models of Akkar and Bommer (2010) and Chiou et al. (2010).}, language = {en} } @article{DiGiulioSavvaidisOhrnbergeretal.2012, author = {Di Giulio, Giuseppe and Savvaidis, Alexandros and Ohrnberger, Matthias and Wathelet, Marc and Cornou, Cecile and Knapmeyer-Endrun, Brigitte and Renalier, Florence and Theodoulidis, Nikos and Bard, Pierre-Yves}, title = {Exploring the model space and ranking a best class of models in surface-wave dispersion inversion application at European strong-motion sites}, series = {Geophysics}, volume = {77}, journal = {Geophysics}, number = {3}, publisher = {Society of Exploration Geophysicists}, address = {Tulsa}, issn = {0016-8033}, doi = {10.1190/GEO2011-0116.1}, pages = {B147 -- B166}, year = {2012}, abstract = {The inversion of surface-wave dispersion curve to derive shear-wave velocity profile is a very delicate process dealing with a nonunique problem, which is strongly dependent on the model space parameterization. When independent and reliable information is not available, the selection of most representative models within the ensemble produced. by the inversion is often difficult. We implemented a strategy in the inversion of dispersion curves able to investigate the influence of the parameterization of the model space and to select a "best" class of models. We analyzed surface-wave dispersion curves measured at 14 European strong..-motion sites within the NERIES EC-Project. We focused on the inversion task exploring the model space by means of four distinct pararneterization classes composed of layers progressively added over a half-space. The classes differ in the definition of the shear-wave velocity profile; we considered models with uniform velocity as well as models with increasing velocity with depth. At each site and for each model parameterization, we performed an extensive surface-wave inversion (200,100 models for five seeds) using the conditional neighborhood algorithm. We addressed the model evaluation following the corrected Akaike's information criterion (AlCc) that combines the concept of misfit to the number of degrees of freedom of the system. The misfit was computed as least-squares estimation between theoretical and observed dispersion curve. The model complexity was accounted in a penalty term by AlCc. By applying such inversion strategy on 14 strong-motion sites, we found that the best parameterization of the model space is mostly three to four layers over a half-space: where the shear-wave velocity of the uppermost layers can follow uniform or power-law dependence with depth. The shear-wave velocity profiles derived by inversion agree with shear-wave velocity profiles provided by borehole surveys at approximately 80\% of the sites.}, language = {en} } @article{DiLuciaTrecalliMuttietal.2012, author = {Di Lucia, Matteo and Trecalli, A. and Mutti, Maria and Parente, Maria}, title = {Bio-chemostratigraphy of the Barremian-Aptian shallow-water carbonates of the southern Apennines (Italy): pinpointing the OAE1a in a Tethyan carbonate platform}, series = {Solid earth}, volume = {3}, journal = {Solid earth}, number = {1}, publisher = {Copernicus}, address = {G{\"o}ttingen}, issn = {1869-9510}, doi = {10.5194/se-3-1-2012}, pages = {1 -- 28}, year = {2012}, abstract = {Low biostratigraphic resolution and lack of chronostratigraphic calibration hinder precise correlations between platform carbonates and coeval deep-water successions. These are the main obstacle when studying the record of Mesozoic oceanic anoxic events in carbonate platforms. In this paper carbon and strontium isotope stratigraphy are used to produce the first chronostratigraphic calibration of the Barremian-Aptian biostratigraphy of the Apenninic carbonate platform of southern Italy. According to this calibration, the segment of decreasing delta C-13 values, leading to the negative peak that is generally taken as the onset of the Selli event, starts a few metres above the last occurrence of Palorbitolina lenticularis and Voloshinoides murgensis. The following rise of delta C-13 values, corresponding to the interval of enhanced accumulation of organic matter in deep-water sections, ends just below the first acme of Salpingoporella dinarica, which roughly corresponds to the segment of peak delta C-13 values. The whole carbon isotope excursion associated with the oceanic anoxic event 1a is bracketed in the Apenninic carbonate platform between the last occurrence of Voloshinoides murgensis and the "Orbitolina level", characterized by the association of Mesorbitolina parva and Mesorbitolina texana. Since these bioevents have been widely recognized beyond the Apenninic platform, the calibration presented in this paper can be used to pinpoint the interval corresponding to the Early Aptian oceanic anoxic event in other carbonate platforms of central and southern Tethys. This calibration will be particularly useful to interpret the record of the Selli event in carbonate platform sections for which a reliable carbon isotope stratigraphy is not available.}, language = {en} } @misc{DormannSchymanskiCabraletal.2012, author = {Dormann, Carsten F. and Schymanski, Stanislaus J. and Cabral, Juliano Sarmento and Chuine, Isabelle and Graham, Catherine and Hartig, Florian and Kearney, Michael and Morin, Xavier and R{\"o}mermann, Christine and Schr{\"o}der-Esselbach, Boris and Singer, Alexander}, title = {Correlation and process in species distribution models: bridging a dichotomy}, series = {Journal of biogeography}, volume = {39}, journal = {Journal of biogeography}, number = {12}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0305-0270}, doi = {10.1111/j.1365-2699.2011.02659.x}, pages = {2119 -- 2131}, year = {2012}, abstract = {Within the field of species distribution modelling an apparent dichotomy exists between process-based and correlative approaches, where the processes are explicit in the former and implicit in the latter. However, these intuitive distinctions can become blurred when comparing species distribution modelling approaches in more detail. In this review article, we contrast the extremes of the correlativeprocess spectrum of species distribution models with respect to core assumptions, model building and selection strategies, validation, uncertainties, common errors and the questions they are most suited to answer. The extremes of such approaches differ clearly in many aspects, such as model building approaches, parameter estimation strategies and transferability. However, they also share strengths and weaknesses. We show that claims of one approach being intrinsically superior to the other are misguided and that they ignore the processcorrelation continuum as well as the domains of questions that each approach is addressing. Nonetheless, the application of process-based approaches to species distribution modelling lags far behind more correlative (process-implicit) methods and more research is required to explore their potential benefits. Critical issues for the employment of species distribution modelling approaches are given, together with a guideline for appropriate usage. We close with challenges for future development of process-explicit species distribution models and how they may complement current approaches to study species distributions.}, language = {en} } @phdthesis{Dulanya2012, author = {Dulanya, Zuze}, title = {Environmental impact on shallow-lake fisheries in Malawi : a coupled catchment-based and palaeolimnological approach}, address = {Potsdam}, pages = {100 S.}, year = {2012}, language = {en} } @article{DuesterhoeftBousquetWichuraetal.2012, author = {D{\"u}sterh{\"o}ft, Erik and Bousquet, Romain and Wichura, Henry and Oberh{\"a}nsli, Roland}, title = {Anorogenic plateau formation The importance of density changes in the lithosphere}, series = {Journal of geophysical research : Solid earth}, volume = {117}, journal = {Journal of geophysical research : Solid earth}, publisher = {American Geophysical Union}, address = {Washington}, issn = {2169-9313}, doi = {10.1029/2011JB009007}, pages = {13}, year = {2012}, abstract = {Away from active plate boundaries the relationships between spatiotemporal variations in density and geothermal gradient are important for understanding the evolution of topography in continental interiors. In this context the classic concept of the continental lithosphere as comprising three static layers of different densities (upper crust, lower crust, and upper mantle) is not adequate to assess long-term changes in topography and relief in regions associated with pronounced thermal anomalies in the mantle. We have therefore developed a one-dimensional model, which is based on thermodynamic equilibrium assemblage computations and deliberately excludes the effects of melting processes like intrusion or extrusions. Our model calculates the "metamorphic density" of rocks as a function of pressure, temperature, and chemical composition. It not only provides a useful tool for quantifying the influence of petrologic characteristics on density, but also allows the modeled "metamorphic" density to be adjusted to variable geothermal gradients and applied to different geodynamic environments. We have used this model to simulate a scenario in which the lithosphere-asthenosphere boundary is subjected to continuous heating over a long period of time (130 Ma), and demonstrate how an anorogenic plateau with an elevation of 1400 m can be formed solely as a result of heat transfer within the continental lithosphere. Our results show that, beside dynamic topography (of asthenospheric origin), density changes within the lithosphere have an important impact on the evolution of anorogenic plateaus.}, language = {en} } @article{EberlePaasche2012, author = {Eberle, Detlef G. and Paasche, Hendrik}, title = {Integrated data analysis for mineral exploration A case study of clustering satellite imagery, airborne gamma-ray, and regional geochemical data suites}, series = {Geophysics}, volume = {77}, journal = {Geophysics}, number = {4}, publisher = {Society of Exploration Geophysicists}, address = {Tulsa}, issn = {0016-8033}, doi = {10.1190/GEO2011-0063.1}, pages = {B167 -- B176}, year = {2012}, abstract = {Partitioning cluster algorithms have proven to be powerful tools for data-driven integration of large geoscientific databases. We used fuzzy Gustafson-Kessel cluster analysis to integrate Landsat imagery,. airborne radiometric, and regional geochemical data to aid in the interpretation of a multimethod database. The survey area extends over 3700 km(2) and is located in the Northern Cape Province, South Africa. We carefully selected five variables for cluster analysis to avoid the clustering results being dominated by spatially high-correlated data sets that were present in our database. Unlike other, more popular cluster algorithms, such as k-means or fuzzy c-means, the Gustafson-Kessel algorithm requires no preclustering data processing, such as scaling or adjustment of histographic data distributions. The outcome of cluster analysis was a classified map that delineates prominent near-to-surface structures. To add value to the classified map, we compared the detected structures to mapped geology and additional geophysical ground-truthing data. We were able to associate the structures detected by cluster analysis to geophysical and geological information thus obtaining a pseudolithology map. The latter outlined an area with increased mineral potential where manganese mineralization, i.e., psilomelane, had been located.}, language = {en} } @article{EhrmannPuppeWanneretal.2012, author = {Ehrmann, Otto and Puppe, Daniel and Wanner, Manfred and Kaczorek, Danuta and Sommer, Michael}, title = {Testate amoebae in 31 mature forest ecosystems - Densities and micro-distribution in soils}, series = {European journal of protistology}, volume = {48}, journal = {European journal of protistology}, number = {3}, publisher = {Elsevier}, address = {Jena}, issn = {0932-4739}, doi = {10.1016/j.ejop.2012.01.003}, pages = {161 -- 168}, year = {2012}, abstract = {We studied testate amoebae and possible correlated abiotic factors in soils of 31 mature forest ecosystems using an easily applicable and spatially explicit method. Simple counting on soil thin-sections with a light microscope resulted in amoeba densities comparable to previously reported values, i.e. 0.1 x 10(8) to 11.5 x 10(8) individuals m(-2) (upper 3 cm of soil). Soil moisture and soil acidity seem to be correlated with amoeba densities. At sites of moderate soil moisture regimes (SMR 2-7) we found higher densities of testate amoebae at pH < 4.5. At wetter sites (SMR >= 8) higher individual densities were recorded also at less acidic sites. The in situ description of amoebae, based on the analysis of a complete soil thin-section, showed a relatively uniform spatial micro-distribution throughout the organic and mineral soil horizons (no testate amoeba clusters). We discuss the pros and cons of the soil thin-section method and suggest it as an additional tool to improve knowledge of the spatial micro-distribution of testate amoebae.}, language = {en} } @article{FaithfullTimmermanUptonetal.2012, author = {Faithfull, J. W. and Timmerman, Martin Jan and Upton, B. G. J. and Rumsey, M. S.}, title = {Mid-Eocene renewal of magmatism in NW Scotland the Loch Roag Dyke, outer hebrides}, series = {Journal of the Geological Society}, volume = {169}, journal = {Journal of the Geological Society}, number = {2}, publisher = {Geological Soc. Publ. House}, address = {Bath}, issn = {0016-7649}, doi = {10.1144/0016-76492011-117}, pages = {115 -- 118}, year = {2012}, abstract = {Amonchquite dyke, in the vicinity of Loch Roag, Lewis, Outer Hebrides has an unusually enriched chemistry, and contains a unique assemblage of megacrysts and xenoliths from the lithosphere of the Hebridean craton. A Ar-40/Ar-39 plateau age of 45.2 +/- 0.2 Ma (2 sigma) of a phlogopite megacryst from the dyke overlaps an earlier reported K-Ar age, and confirms that the British Palaeogene Igneous Province extended into the Eocene. Similar late low-volume melts were erupted in the Eocene and Oligocene in West and East Greenland, suggesting that such late-stage magmatic rejuvenescence is a widespread feature across the North Atlantic Igneous Province.}, language = {en} } @article{FanvanWestenKorupetal.2012, author = {Fan, Xuanmei and van Westen, Cees J. and Korup, Oliver and Gorum, Tolga and Xu, Qiang and Dai, Fuchu and Huang, Runqiu and Wang, Gonghui}, title = {Transient water and sediment storage of the decaying landslide dams induced by the 2008 Wenchuan earthquake, China}, series = {Geomorphology : an international journal on pure and applied geomorphology}, volume = {171}, journal = {Geomorphology : an international journal on pure and applied geomorphology}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0169-555X}, doi = {10.1016/j.geomorph.2012.05.003}, pages = {58 -- 68}, year = {2012}, abstract = {Earthquake-triggered landslide dams are potentially dangerous disrupters of water and sediment flux in mountain rivers, and capable of releasing catastrophic outburst flows to downstream areas. We analyze an inventory of 828 landslide dams in the Longmen Shan mountains, China, triggered by the M-w 7.9 2008 Wenchuan earthquake. This database is unique in that it is the largest of its kind attributable to a single regional-scale triggering event: 501 of the spatially clustered landslides fully blocked rivers, while the remainder only partially obstructed or diverted channels in steep watersheds of the hanging wall of the Yingxiu-Beichuan Fault Zone. The size distributions of the earthquake-triggered landslides, landslide dams, and associated lakes (a) can be modeled by an inverse gamma distribution; (b) show that moderate-size slope failures caused the majority of blockages; and (c) allow a detailed assessment of seismically induced river-blockage effects on regional water and sediment storage. Monte Carlo simulations based on volumetric scaling relationships for soil and bedrock failures respectively indicate that 14\% (18\%) of the estimated total coseismic landslide volume of 6.4 (14.6) x 10(9) m(3) was contained in landslide dams, representing only 1.4\% of the >60,000 slope failures attributed to the earthquake. These dams have created storage capacity of similar to 0.6x 10(9) m(3) for incoming water and sediment. About 25\% of the dams containing 2\% of the total river-blocking debris volume failed one week after the earthquake; these figures had risen to 60\% (similar to 20\%), and >90\% (>90\%) within one month, and one:year, respectively, thus also emptying similar to 92\% of the total potential water and sediment storage behind these, dams within one year following the earthquake. Currently only similar to 0.08 x 10(9) m(3) remain available as natural reservoirs for storing water and sediment, while similar to 0.19 x 10(9) m(3), i.e. about a third of the total river-blocking debris volume, has been eroded by rivers. Dam volume and upstream catchment area control to first order the longevity of the barriers, and bivariate domain plots are consistent with the observation that most earthquake-triggered landslide dams were ephemeral. We conclude that the river-blocking portion of coseismic slope failures disproportionately modulates the post-seismic sediment flux in the Longmen Shan on annual to decadal timescales.}, language = {en} } @article{FrijiaDiLuciaVicedoetal.2012, author = {Frijia, Gianluca and Di Lucia, Matteo and Vicedo, Vicent and G{\"u}nter, Christina and Ziemann, Martin Andreas and Mutti, Maria}, title = {An extraordinary single-celled architect A multi-technique study of the agglutinated shell of the larger foraminifer Mesorbitolina from the Lower Cretaceous of southern Italy}, series = {Marine micropaleontology}, volume = {90-91}, journal = {Marine micropaleontology}, number = {7}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0377-8398}, doi = {10.1016/j.marmicro.2012.04.002}, pages = {60 -- 71}, year = {2012}, abstract = {Orbitolinids are larger foraminifera widespread in Lower Cretaceous shallow-water carbonates of the Tethyan realm. They are among the most important fossil groups used for Biostratigraphy. Despite this and although the structural features of the group have been described in detail, very little is known about the composition of their agglutinated test and the process by which they selected foreign grains. In this study, the test of Orbitolina d'Orbigny, 1850 (subgenus Mesorbitolina Schroeder, 1962) from Aptian shallow-water carbonate deposits of southern Italy has been studied in detail. We combine petrographic techniques (optical microscope and SEM) with energy-dispersive x-ray spectrometry (EDS), electron probe microanalyzer (EPMA), X-ray diffraction and Raman spectroscopy analyses. The results show that the test of Mesorbitolina is composed of carbonate and non-carbonate agglutinated grains with the latter distributed across the test with a specific pattern, moving from the marginal to the central zone. In the marginal zone, non-carbonate grains are found only in the epidermis and along the septa which are composed of quartz, with smaller amounts of illite/muscovite and K-feldspar grains. In the central zone of the test, non-carbonate grains are distributed in two ways. Coarse grains of quartz and K-feldspar are abundant and randomly placed in the endoskeleton embedded in a mosaic of minute carbonate grains. Flat grains, mainly of illite/muscovite constitute the external part of the septa. Our observations indicate that Mesorbitolina did select and place agglutinated grains across its test, mainly according to their shape, whereas it did not select particles according to grain size. The distribution of agglutinated particles according to their mineralogical composition shows some contradictory evidence and therefore, at the moment, grain selection in function of mineralogy cannot be completely confirmed or ruled out. Analogies in the test composition of Mesorbitolina specimens from coeval deposits from different areas of southern Italy indicate that the features of their agglutinated test are typical characters of the genus Mesorbitolina. However, it is still unclear what advantage was obtained by the foraminifer by the described test features.}, language = {en} }