Detailseite
Projekt
Late Quaternary Climate Reconstruction at Lake El'gygytgyn - Stable oxygen isotopes in biogenic opal of lacustrine diatoms
Antragsteller
Dr. Hanno Meyer
Fachliche Zuordnung
Mineralogie, Petrologie und Geochemie
Förderung
Förderung von 2007 bis 2012
Projektkennung
Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 36739403
Lake El’gygytgyn, located in the NE Siberian Arctic, was formed by a meteoritic impact approximately 3.6 Mio a ago. It is a unique archive of climate and environmental history for this period in the Arctic by its most likely continuous and undisturbed sedimentary sequence. The sediments are abundant (up to 30%) in diatoms, whereas other bioindicators such as ostracods and forams are missing. Therefore, the oxygen isotopic composition of lacustrine biogenic silica of Lake El’gygytgyn will be used to quantitatively trace climate and environmental changes by means of isotope geochemistry. Biogenic silica in lake sediments is primarily derived from diatoms, photosynthetic algae that secrete internal shells composed of silica (SiO2 . nH2O). The oxygen isotopic composition of biogenic silica (δ18OSi) has recently been shown to be a useful palaeoclimatic indicator that reflects the oxygen isotopic composition of the water in which it formed (Shemesh et al., 1992). Since the isotopic composition of lake water is a direct indicator of precipitation and temperature, δ18OSi correlates directly to regional climate. Recent studies in lacustrine records confirm the high potential of oxygen isotopic analyses in biogenic silica to qualitatively and quantitatively estimate changes in temperature, precipitation, and evaporation (e. g. Leng and Marshall, 2004). A new technique has been developed at AWI Potsdam for small sample sizes (1-4 mg SiO2) and shall now be applied for the first time to a North Siberian Lake. Main aim of the project is a reconstruction of the palaeoenvironmental and palaeoclimate history in this region for the Late Quaternary using material cored during the expeditions between 1998 and 2003. The expected results will be the base for studying the climate history using stable isotopes in lacustrine diatoms of the whole sedimentary sequence at Lake El’gygygtgyn, coring of which is planned for spring 2009 in the frame of the ICDP programme. This proposal gives an outline of the planned studies during the duration of the project and applies for DFG funding of a third year.
DFG-Verfahren
Infrastruktur-Schwerpunktprogramme
