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Projekt
Permafrost history in Arctic Siberia - insights from the cryogenic weathering record at Elgygytgyn crater, NE Siberia
Antragsteller
Dr. Georg Schwamborn
Fachliche Zuordnung
Mineralogie, Petrologie und Geochemie
Förderung
Förderung von 2008 bis 2009
Projektkennung
Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 64591067
This proposal focusses on determining climate variations as expressed in variations of permafrost conditions in Arctic Siberia. Of particular interest is the establishment of a sedimentological method that allows estimating the degree of cryogenic weathering and palaeo soil temperatures through geologic time. The study explores a lake sediment record from Elgygytgyn crater lake, NE Siberia, spanning the last 300,000 years and currently representing the longest terrestrial palaeoclimate and -environment archive for the Arctic. Samples from short permafrost cores extracted in the catchment and spanning the last 14,000 years and a set of surface samples that represent modern conditions will be used as a reference. The following sediment-mineralogical properties, which are considered to mirror long term periglacial dynamics in NE Siberia, will be studied: (1) the ratio of quartz to feldspar in selected grain size fractions provides an indicator reflecting the degree of frost weathering; (2) image analysis of scanning electron micrographs of particles will be performed to yield a quantification of quartz grain morphology and surface features stemming from frost weathering; (3) heavy minerals will be used as provenance indicators to define changes in source rock composition and cryogenic detritus. The results prepare a fundamental tool that allows determining the intensity of permafrost conditions through Quaternary glacial cycles in the North Siberian Arctic. This is a conceptual outcome of future core studies from ICDP funded deep drillings.
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