Description: Das Projekt "Patagonia Lake Transect (PaLaTra): Rekonstruktion von Veraenderungen der Paleoumwelt im Spaetquartaer in der suedlichen Hemisphaere" wird vom Umweltbundesamt gefördert und von Universite de Geneve, Departement de Geologie et Paleontologie durchgeführt. This project corresponds to the second phase of the Patagonia Lake Transect (PaLaTra), a multidisciplinary, international collaborative effort to reconstruct the paleoenvironmental evolution of southern Patagonia using lake sediments. Two closed lake basins in Patagonia, Argentina, Lago Cardiel and Laguna Cari-Laufquen, located at 49 degree and 41 degree S, respectively, were investigated in the first phase of the project PaLaTra. We completed the main goals of this phase: 1) to survey and sample the modern lake and terrestrial environments for climate calibration of the sedimentary record; 2) to develop the necessary logistic framework; 3) to undertake seismic surveys of the sediments to image sediment geometry, reconstruct lake level fluctuations, and to identify optimal coring sites; and 4) to retrieve and analyze long (up to 12 m) sedimentary cores to determine the paleoclimatic information that is stored in the sedimentary record. Our first results show that both basins demonstrate high sensitivity to record late Pleistocene-Holocene climate by large lake-level fluctuations. Laguna Cari-Laufquen has undergone periods of Late Holocene desiccation that alternate with intervals of higher lake levels. In Lago Cardiel, well-defined seismic units with distinctive sequence boundaries - imaged to a sediment depth of over 70 m - document lake-level changes of more than 80 m below present. Seismic profiles indicate large variation in sedimentation rates, lateral facies changes, and undisturbed, finely layered basinal sediment packages. Down core sedimentological analyses, radiocarbon dates, ostracodes, diatoms, pollen, stable isotopes on ostracodes and diverse authigenic carbonates, of selected short and long sediment cores indicate marked paleolimnologic and paleoenvironmental changes. Based on our Phase I evaluation, we plan to continue analyzing the obtained cores from both lacustrine basins and concentrate additional field work on Lago. 1. Analyze the sediment cores recovered during Phase I in both sites. Whereas a Holocene sequence was recovered from Laguna Cari-Lauquen, Lago Cardiel sedimentary cores contain older sediments. Estimated from our combined radiocarbon and ash chronology, the retrieved cores date back beyond 18,000 B.P. Magnetic, sedimentological, and geochemical stratigraphy (including stable isotopes on carbonates and organic matter), along with paleoecological stratigraphies for pollen, charcoal, diatoms, and ostracodes (including stable isotopes and amino acid racemization for chronological assessment) will provide a unique multi-proxy set of data at this latitude of the Southern Hemisphere. 2. Develop a 3-dimensional sediment and tectonic basin history of Lago Cardiel comprising the total sedimentary infill above the bedrock. Taking advantage of the temporary boat on the lake (Fig. 2), an additional airgun seismic survey is planned in Lago Cardiel which complements the already performed high-resolution 3.5 kHz survey. This deep
Types:
SupportProgram
Origin: /Bund/UBA/UFORDAT
Tags: Tierhaltungsanlage ? Aminosäure ? Holzkohle ? Paläoklimatologie ? Paläoökologie ? Seen ? Carbonat ? Asche ? Diatomeen ? Kalibrierung ? Seensediment ? Geografische Koordinaten ? Argentinien ? Main ? Airgun ? Tektonik ? Klimavariabilität ? Binnengewässer ? Plattentektonik ? Sedimentanalyse ? Sedimentkern ? Stratigraphie ? Organisches Material ? Gewässersediment ? Paläontologie ? Evolution ? Schiff ? Geologie ? Standortwahl ? Trocknung ? Sediment ? Gewerbebetrieb ? Bohrkern ? Interdisziplinarität ? Pollenanalyse ? Internationale Zusammenarbeit ? Isotop ? Daten ? Klimaentwicklung ? Sedimentation ? Verpackung ? Pollen ? Lago-Cardiel ? Patagonien ? Pleistozaen ? Holozaen ? Laguna-Cari-Laufquen ?
License: cc-by-nc-nd/4.0
Language: Deutsch
Time ranges: 1998-01-01 - 2000-12-31
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