HR: 1330h
AN: PP32B-0297    [PDF]
TI: Reconstruction of Late Quaternary Climate in Central Europe - A Comparison of Stable Isotope and Trace Element Variations in Speleothems From Different Cave Systems in Germany.
AU: * Nordhoff, P
EM: pnordho@gwdg.de
AF: Dept. of Isotope Geology Geoscience Center Goettingen, Goldschmidtstr. 3, Goettingen, 37077 Germany
AU: Wiegand, B
EM: bwiegand@pangea.stanford.edu
AF: Dept. of Geol. and Environm. Sciences Stanford University, 367 Panama Mall, Stanford, CA 94305-2115 United States
AU: Simon, K
AF: Dept. of Geochemistry Geoscience Center Goettingen, Goldschmidtstr. 1-3, Goettingen, 37077 Germany
AU: Rosendahl, W
AF: Inst. for Applied Geosciences TU Darmstadt, Schnittspahnstr. 9, Darmstadt, 64287 Germany
AU: Hansen, B T
AF: Dept. of Isotope Geology Geoscience Center Goettingen, Goldschmidtstr. 3, Goettingen, 37077 Germany
AU: Kempe, S
AF: Inst. for Applied Geosciences TU Darmstadt, Schnittspahnstr. 9, Darmstadt, 64287 Germany
AB: Speleothems (stalagmites, stalactites, flowstones) are important archives for Late Quaternary continental climatic and paleo-environmental reconstruction. Speleothems form when calcium carbonate precipitates from solutions seeping into caves hosted e.g. in limestone or dolomite complexes. Information of past climate variability and changes in local environmental conditions can be obtained from signatures of the stable isotopes of oxygen and carbon as well as trace element pattern recorded in speleothems. Reconstruction of paleo-temperature and past environmental conditions from stable isotopes, however, require isotopic equilibrium between the drip water and the precipitating calcium carbonate. Results from Dietzel et al. (1992) and Johnson and Ingram (2001) indicate that the formation of modern travertine and speleothem calcite occurs under isotopic equilibrium. Factors that influence the stable oxygen and carbon isotope composition during speleothem precipitation include e.g. the moisture source and precipitation, photosynthetic pathways, the bedrock proportion, and the drip rate. This often leads to a situation with several variables. However, a specific interpretation is possible when dealing with environments where only one of the factors is dominant, or specific settings are assumed to be invariant, or further proxies like trace element variations help to define the frame conditions during speleothem formation. Concentrations of trace elements (e.g. Sr, Mg) which are co-precipitated with calcite are related to changes in the composition of the solution and strongly depend on the dissolution/precipitation dynamics along drip water flow paths. In a multiproxy approach they are a valuable tool for the interpretation of the recorded stable isotope variations. We present first results from different cave systems located in the Swabian Alps and the Harz Mountains (Germany). Our study includes a high-resolution multiproxy approach, using U/Th-TIMS data, stable oxygen/carbon isotope data, and geochemical compositions of speleothems, covering ages from the Late Pleistocene to the Early Holocene. The results are compared to geochemical data from host rocks, soil zones, cave sediments, drip water compositions, and recent calcium carbonate precipitates. Understanding the response of a cave system to the actual climatic, hydrologic and environmental regimen is a main requirement for the interpretation of "paleo-information" conserved in speleothems in order to lead to a coherent picture of past continental climate dynamics.\\{\it References: Dietzel M., Usdowski E., and Hoefs J., (1992): Applied Geochemistry 7: 177-184. Johnson, K.R. and Ingram, B.L. (2001): Abstract volume, 4th Internat. Symp. On Applied Isotope Geochemistry, Pacific Groove, USA: 70-72.}
DE: 1040 Isotopic composition/chemistry
DE: 1065 Trace elements (3670)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2003 Fall Meeting