TY - JOUR A1 - Pilz, Marco A1 - Parolai, Stefano A1 - Leyton, Felipe A1 - Campos, Jaime A1 - Zschau, Jochen T1 - A comparison of site response techniques using earthquake data and ambient seismic noise analysis in the large urban areas of Santiago de Chile N2 - Situated in an active tectonic region, Santiago de Chile, the country's capital with more than six million inhabitants, faces tremendous earthquake risk. Macroseismic data for the 1985 Valparaiso event show large variations in the distribution of damage to buildings within short distances, indicating strong effects of local sediments on ground motion. Therefore, a temporary seismic network was installed in the urban area for recording earthquake activity and a study was carried out aiming to estimate site amplification derived from horizontal-to- vertical (H/V) spectral ratios from earthquake data (EHV) and ambient noise (NHV), as well as using the standard spectral ratio (SSR) technique with a nearby reference station located on igneous rock. The results lead to the following conclusions: The analysis of earthquake data shows significant dependence on the local geological structure with respect to amplitude and duration. An amplification of ground motion at frequencies higher than the fundamental one can be found. This amplification would not be found when looking at NHV ratios alone. The analysis of NHV spectral ratios shows that they can only provide a lower bound in amplitude for site amplification. P-wave site responses always show lower amplitudes than those derived by S waves, and sometimes even fail to provide some frequencies of amplification. No variability in terms of time and amplitude is observed in the analysis of the H/V ratio of noise. Due to the geological conditions in some parts of the investigated area, the fundamental resonance frequency of a site is difficult to estimate following standard criteria proposed by the SESAME consortium, suggesting that these are too restrictive under certain circumstances. Y1 - 2009 UR - http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1365-246X U6 - https://doi.org/10.1111/j.1365-246X.2009.04195.x SN - 0956-540X ER - TY - JOUR A1 - Mulch, Andreas A1 - Uba, Cornelius Eji A1 - Strecker, Manfred A1 - Schonberg, Ronald A1 - Chamberlain, C. Page T1 - A Late Miocene stable isotope paleosoil record of Andean foreland precipitation Y1 - 2009 UR - http://www.sciencedirect.com/science/journal/00167037 SN - 0016-7037 ER - TY - JOUR A1 - Seifert, Wolfgang A1 - Rhede, Dieter A1 - Förster, Hans-Jürgen A1 - Thomas, Rainer T1 - Accessory minerals as fingerprints for the thermal history and geochronology of the Caledonian Rumburk granite N2 - Accessory minerals of the Caledonian Rumburk granite are investigated to gain insight into its magmatic and post-magmatic evolution history. Recent geothermometers calibrated for trace elements in rutile (Zr), zircon (Ti), and quartz (Ti) were used to determine mineral-formation temperatures, which are compared with T data obtained from melt and fluid-inclusion Studies on quartz. Improved electron-microprobe analytical conditions allowed distinguishing several generations of rutile. Submicron-sized rutile needles included in quartz crystallized at around 739 +/- 13 degrees C and, thus, are evidently magmatic. Simultaneous crystallization of the high-T rutile and quartz is the favoured concept compared with an exsolution model for the needles. Th-U-total Pb dating of xenotime-(Y) by electron microprobe yielded a bimodal age distribution of 494 +/- 8 Ma (2 sigma; n = 44) and 311 +/- 8 Ma (2 sigma; n = 48), which is missing in monazite-(Ce). The older age correlates with the early Ordovician granite emplacement age Suggested by earlier isotopic Studies. The younger Carboniferous age also may be geologically reasonable, because the granite experienced a minor tectonothermal overprint during the Variscan orogenesis. However, whether this event has caused the resetting of the isotopic system in the xenotime is uncertain. This also holds for the age of the partial breakdown of monazite and xenotime into reaction coronas composed of fluorapatite, allanite-(Ce), epidote +/- clinozoisite. This alteration assemblage was likely produced already during autometasomatic reworking of the solidifying magma in Ordovician time, but it cannot be excluded that it relates to a Carboniferous fluid imprint connected with late-Variscan processes. Y1 - 2009 UR - http://www.ingentaconnect.com/content/schweiz/njma U6 - https://doi.org/10.1127/0077-7757/2009/0147 SN - 0077-7757 ER - TY - JOUR A1 - Wiederkehr, Michael A1 - Sudo, Masafumi A1 - Bousquet, Romain A1 - Berger, Alfons A1 - Schmid, Stefan M. T1 - Alpine orogenic evolution from subduction to collisional thermal overprint : the Ar-40/Ar-39 age constraints from the Valaisan Ocean, central Alps N2 - The investigated HP/LT metasedimentary units of the Valaisan and adjacent European domains occupy a key position in the Alpine belt for understanding the transition from early subduction-related HP/LT metamorphism to collision-related Barrovian overprint and the evolution of mountain belts in general. The timing of high-pressure metamorphism, subsequent retrogression and following Barrow-type overprint was studied by Ar-40/Ar-39 dating of biotite and several white mica generations that are well characterized in terms of mineral chemistry, texture and associated mineral assemblages. Four distinct age populations of white mica record peak pressure conditions (42-40 Ma) and several stages of subsequent retrograde metamorphic evolution (36-25 Ma). Biotite isotopic analyses yield consistent apparent ages that cluster around 18-16 Ma for the Barrow-type thermal overprint. The recorded isotopic data reveal a significant time gap in the order of some 20 Ma between subduction-related HP/LT metamorphism and collision-related Barrovian overprint, supporting the notion of a polymetamorphic evolution associated with a bimodal P-T path. Y1 - 2009 UR - http://www.agu.org/journals/tc/ U6 - https://doi.org/10.1029/2009tc002496 SN - 0278-7407 ER - TY - JOUR A1 - Kallmeyer, Jens A1 - Smith, David C. T1 - An improved electroelution method for separation of DNA from humic substances in marine sediment DNA extracts N2 - We present a method for the rapid and simple extraction of DNA from marine sediments using electroelution. It effectively separates DNA from compounds, including humic substances, that interfere with subsequent DNA quantification and amplification. After extraction of the DNA from the sediment into an aqueous solution, the crude sample is encased in 2% agarose gel and exposed to an electrical current, which draws the DNA out of the gel into a centrifugal filter vial. After electroelution, the sample is centrifuged to remove contaminants <= 100 000 Da. Recovery of DNA using this method is quantitative and does not discriminate on the basis of size, as determined using DNA standards and DNA extracts from environmental samples. Amplification of DNA is considerably improved due to removal of PCR inhibitors. For Archaea, only these purified extracts yielded PCR products. This method allows for the use of relatively large volumes of sediment and is particularly useful for sediments containing low biomass such as deeply buried marine sediments. It works with both organic-rich and -poor sediment, as well as with sediment where calcium carbonate is abundant and sediment where it is limited; consequently, adjustment of protocols is unnecessary for samples with very different organic and mineral contents. Y1 - 2009 UR - http://www3.interscience.wiley.com/cgi-bin/issn?DESCRIPTOR=PRINTISSN&VALUE=0168-6496 U6 - https://doi.org/10.1111/j.1574-6941.2009.00684.x SN - 0168-6496 ER - TY - JOUR A1 - Weber, Michael H. A1 - Abu-Ayyash, Khalil A1 - Abueladas, Abdel-Rahman A1 - Agnon, Amotz A1 - Alasonati-Tašárová, Zuzana A1 - Al-Zubi, Hashim A1 - Babeyko, Andrey A1 - Bartov, Yuval A1 - Bauer, Klaus A1 - Becken, Michael A1 - Bedrosian, Paul A. A1 - Ben-Avraham, Zvi A1 - Bock, Günter A1 - Bohnhoff, Marco A1 - Bribach, Jens A1 - Dulski, Peter A1 - Ebbing, Joerg A1 - El-Kelani, Radwan J. A1 - Foerster, Andrea A1 - Förster, Hans-Jürgen A1 - Frieslander, Uri A1 - Garfunkel, Zvi A1 - Götze, Hans-Jürgen A1 - Haak, Volker A1 - Haberland, Christian A1 - Hassouneh, Mohammed A1 - Helwig, Stefan L. A1 - Hofstetter, Alfons A1 - Hoffmann-Rothe, Arne A1 - Jaeckel, Karl-Heinz A1 - Janssen, Christoph A1 - Jaser, Darweesh A1 - Kesten, Dagmar A1 - Khatib, Mohammed Ghiath A1 - Kind, Rainer A1 - Koch, Olaf A1 - Koulakov, Ivan A1 - Laske, Maria Gabi A1 - Maercklin, Nils T1 - Anatomy of the Dead Sea transform from lithospheric to microscopic scale N2 - Fault zones are the locations where motion of tectonic plates, often associated with earthquakes, is accommodated. Despite a rapid increase in the understanding of faults in the last decades, our knowledge of their geometry, petrophysical properties, and controlling processes remains incomplete. The central questions addressed here in our study of the Dead Sea Transform (DST) in the Middle East are as follows: (1) What are the structure and kinematics of a large fault zone? (2) What controls its structure and kinematics? (3) How does the DST compare to other plate boundary fault zones? The DST has accommodated a total of 105 km of left-lateral transform motion between the African and Arabian plates since early Miocene (similar to 20 Ma). The DST segment between the Dead Sea and the Red Sea, called the Arava/Araba Fault (AF), is studied here using a multidisciplinary and multiscale approach from the mu m to the plate tectonic scale. We observe that under the DST a narrow, subvertical zone cuts through crust and lithosphere. First, from west to east the crustal thickness increases smoothly from 26 to 39 km, and a subhorizontal lower crustal reflector is detected east of the AF. Second, several faults exist in the upper crust in a 40 km wide zone centered on the AF, but none have kilometer-size zones of decreased seismic velocities or zones of high electrical conductivities in the upper crust expected for large damage zones. Third, the AF is the main branch of the DST system, even though it has accommodated only a part (up to 60 km) of the overall 105 km of sinistral plate motion. Fourth, the AF acts as a barrier to fluids to a depth of 4 km, and the lithology changes abruptly across it. Fifth, in the top few hundred meters of the AF a locally transpressional regime is observed in a 100-300 m wide zone of deformed and displaced material, bordered by subparallel faults forming a positive flower structure. Other segments of the AF have a transtensional character with small pull-aparts along them. The damage zones of the individual faults are only 5-20 m wide at this depth range. Sixth, two areas on the AF show mesoscale to microscale faulting and veining in limestone sequences with faulting depths between 2 and 5 km. Seventh, fluids in the AF are carried downward into the fault zone. Only a minor fraction of fluids is derived from ascending hydrothermal fluids. However, we found that on the kilometer scale the AF does not act as an important fluid conduit. Most of these findings are corroborated using thermomechanical modeling where shear deformation in the upper crust is localized in one or two major faults; at larger depth, shear deformation occurs in a 20-40 km wide zone with a mechanically weak decoupling zone extending subvertically through the entire lithosphere. Y1 - 2009 UR - http://www.agu.org/journals/rg/ U6 - https://doi.org/10.1029/2008rg000264 SN - 8755-1209 ER - TY - JOUR A1 - Carrapa, Barbara A1 - DeCelles, Peter G. A1 - Reiners, Peter W. A1 - Gehrels, George E. A1 - Sudo, Masafumi T1 - Apatite triple dating and white mica Ar-40/Ar-39 thermochronology of syntectonic detritus in the Central Andes : a multiphase tectonothermal history N2 - We applied apatite U-Pb, fission track, and (U-Th)/He triple dating and white mica Ar-40/Ar-39 thermochronology to syntectonic sedimentary rocks from the central Andean Puna plateau in order to determine the source-area geochronology and source sedimentary basin thermal histories, and ultimately the timing of multiple tectonothermal events in the Central Andes. Apatite triple dating of samples from the Eocene Geste Formation in the Salar de Pastos Grandes basin shows late Precambrian-Devonian apatite U-Pb crystallization ages, Eocene apatite fission track (AFT), and Eocene-Miocene (U-Th)/He (ca. 8-47 Ma) cooling ages. Double dating of cobbles from equivalent strata in the Arizaro basin documents early Eocene (46.2 +/- 3.9 Ma) and Cretaceous (107.6 +/- 7.6, 109.5 +/- 7.7 Ma) AFT and Eocene-Oligocene (ca. 55-30 Ma) (U-Th)/He ages. Thermal modeling suggests relatively rapid cooling between ca. 80 and 50 Ma and reheating and subsequent diachronous basin exhumation between ca. 30 Ma and 5 Ma. The Ar-40/Ar-39 white mica ages from the same samples in the Salar de Pastos Grandes area are mainly 400-350 Ma, younger than apatite U-Pb ages, suggesting source- terrane cooling and exhumation during the Devonian-early Carboniferous. Together these data reveal multiple phases of mountain building in the Paleozoic and Cenozoic. Basin burial temperatures within the plateau were limited to <80 degrees C and incision occurred diachronously during the Cenozoic. Y1 - 2009 UR - http://geology.gsapubs.org/ U6 - https://doi.org/10.1130/G25698a.1 SN - 0091-7613 ER - TY - THES A1 - Anderssohn, Jan T1 - Applikationen der SAR-Interferometrie zur Untersuchung von Oberflächendeformationen : Grundlage hydrologischer, geologischer, vulkanologischer und seismischer Studien Y1 - 2009 CY - Potsdam ER - TY - JOUR A1 - Förster, Hans-Jürgen A1 - Romer, Rolf L. A1 - Gottesmann, Bärbel A1 - Tischendorf, Gerhard A1 - Rhede, Dieter T1 - Are the granites of the Aue-Schwarzenberg Zone (Erzgebirge, Germany) a major source for metalliferous ore deposits? : a geochemical, Sr-Nd-Pb isotopic, and geochronological study N2 - The Aue-Schwarzenberg Granite Zone (ASGZ), in the western Erzgebirge of Germany, is composed of small, late- Variscan F-poor biotite and two-mica granites. The biotite granites (Aue granite suite, Beierfeld, Bernsbach) are weakly to mildly peraluminous (A/CNK = 1.07-1.14; 70-76 wt% SiO2), display similar Sr-87/Sr-86 initial ratios (0.7065-0.7077; t = 325 Ma), and exhibit a narrow range in epsilon Nd-325 (-2.6 to -3.5). They are closely affiliated compositionally with the biotite granites in the distant, more voluminous Nejdek massif (Czech Republic). The two-mica granites (Schwarzenberg granite suite, Lauter) are Si-rich (74-77 wt% SiO2) and mildly to strongly peraluminous (A/CNK = 1.17- 1.26). The granites from Schwarzenberg Lire distinctly higher in their Sr(i)ratios (0.709-0.713; t = 325 Ma) and possess lower values of epsilon Nd-325 (-4.9 to -5.2) relative to the biotite granites. The Lauter granites have a Nd-isotopic composition between -3.6 and -4.0 (t = 325 Ma). Mean Th-U-total Pb uraninite ages (Ma +/- 2 sigma) obtained for the granites from the Aue Suite (324.3 +/- 3. 1), Beierfeld (323.7 +/- 3.1), Bernsbach (320.7 +/- 2.9), Schwarzenberg (323.3 +/- 2.4), and the Kirchberg granite al Burkersdorf (322.7 +/- 3.5) indicate that magmatism in the ASGZ commenced in the Namurian and took place early within the major episode of granite formation in the Erzgebirge-Vogtland zone (327-318 Ma). Geochemical and mineralogical patterns of variably altered samples imply that the ASGZ granites are unlikely to have significantly contributed to the formation of spatially associated metalliferous ore deposits (Sn, W, Mo, Ph, Zn, Bi, Co, Ni), except for uranium. In particular the Aue granite suite should have served as major Source for U accumulated in the economically important post-granitic deposits of Schneeberg and Schlema-Alberoda. Y1 - 2009 UR - http://www.schweizerbart.de/j/n-jb-min/ U6 - https://doi.org/10.1127/0077-7757/2009/0138 SN - 0077-7757 ER - TY - JOUR A1 - Breuer, Lutz A1 - Willems, Patrick A1 - Bormann, Helge A1 - Bronstert, Axel A1 - Croke, Barry A1 - Frede, Hans Georg A1 - Gräff, Thomas A1 - Hubrechts, Lode A1 - Kite, Geoffrey A1 - Lanini, Jordan A1 - Leavesley, George A1 - Lettenmaier, Dennis P. A1 - Lindstroem, Goeran A1 - Seibert, Jan A1 - Sivapalan, Mayuran A1 - Viney, Neil R. T1 - Assessing the impact of land use change on hydrology by ensemble modeling (LUCHEM) : I: model intercomparison with current land use N2 - This paper introduces the project on 'Assessing the impact of land use change on hydrology by ensemble modeling (LUCHEM)' that aims at investigating the envelope of predictions on changes in hydrological fluxes due to land use change. As part of a series of four papers, this paper outlines the motivation and setup of LUCHEM, and presents a model intercomparison for the present-day simulation results. Such an intercomparison provides a valuable basis to investigate the effects of different model structures on model predictions and paves the ground for the analysis of the performance of multi-model ensembles and the reliability of the scenario predictions in companion papers. in this study, we applied a set of 10 lumped, semi-lumped and fully distributed hydrological models that have been previously used in land use change studies to the low mountainous Dill catchment. Germany. Substantial differences in model performance were observed with Nash-Sutcliffe efficiencies ranging from 0.53 to 0.92. Differences in model performance were attributed to (1) model input data, (2) model calibration and (3) the physical basis of the models. The models were applied with two sets of input data: an original and a homogenized data set. This homogenization of precipitation, temperature and leaf area index was performed to reduce the variation between the models. Homogenization improved the comparability of model simulations and resulted in a reduced average bias, although some variation in model data input remained. The effect of the physical differences between models on the long-term water balance was mainly attributed to differences in how models represent evapotranspiration. Semi-lumped and lumped conceptual models slightly outperformed the fully distributed and physically based models. This was attributed to the automatic model calibration typically used for this type of models. Overall, however, we conclude that there was no superior model if several measures of model performance are considered and that all models are suitable to participate in further multi-model ensemble set-ups and land use change scenario investigations. Y1 - 2009 UR - http://www.sciencedirect.com/science/journal/03091708 U6 - https://doi.org/10.1016/j.advwatres.2008.10.003 SN - 0309-1708 ER -