부산대학교 도서관

The analysis of the stable oxygen isotopes .sup.18 O and .sup.16 O has revolutionized paleoclimate research since the middle of the last century. Particularly, [delta].sup.18 O of ice cores from Greenland and Antarctica is used as a paleotemperature proxy, and [delta].sup.18 O of deep-sea sediments is used as a proxy for global ice volume. Important terrestrial archives to which [delta].sup.18 O as a paleoclimate proxy is successfully applied are speleothems, lake sediments, or tree rings. By contrast, [delta].sup.18 O applications to loess-paleosol sequences (LPSs) are scarce. Here we present a first continuous [delta].sup.18 O record (n=50) for the LPS Crvenka in Serbia, southeastern Europe, spanning the last glacial-interglacial cycle (since 145 ka). From a methodological point of view, we took advantage of a recently proposed paleoclimate/paleohydrological proxy based on bulk [delta].sup.18 O analyses of plant-derived lipids. The Crvenka [delta].sup.18 O.sub.bulk lipid values range between -10.2 0/00 and +23.0 0/00 and are systematically more positive in the interglacial and interstadial (paleo-)soils corresponding to marine oxygen-isotope stage (MIS) 1, 3, and 5, compared to the loess layers (MIS 2, 4, and 6). Our Crvenka [delta].sup.18 O.sub.bulk lipid record provides no evidence for the occurrence of interstadials and stadials comparable to the Dansgaard-Oeschger events known from the Greenland [delta].sup.18 O.sub.ice core records. Concerning the interpretation of our Crvenka [delta].sup.18 O.sub.bulk lipid record, plant-derived lipids such as fatty acids and alcohols are certainly strongly influenced by climatic factors such as temperature (via [delta].sup.18 O.sub.precipitation) and relative air humidity (via .sup.18 O enrichment of leaf water due to evapotranspiration). However, pool effects in the form of non-water-correlated lipids such as sterols or the input of root-derived lipids need to be considered, too. Similarly, the input of soil-microbial lipids and oxygen exchange reactions represent uncertainties challenging quantitative paleoclimate/paleohydrological reconstructions based on [delta].sup.18 O.sub.bulk lipid analyses from LPSs.