COLLABORATIVE RESEARCH: High Resolution, Interdisciplinary Paleoclimatic Studies of Late Quaternary Lacustrine Systems in Mongolia

点击翻译按钮获取中文摘要

9709343 Williams This Proposal requests a three year award to do high-resolution, interdisciplinary studies of Late Quaternary paleoclimate change as recorded in lacustrine sediment from Lakes Telmen and Dood Mongolia. During the first two years, a lake coring and catchment sediment and soil sampling program will take place during the summer, when access to these lakes is possible. The proposed paleoclimate study is system-wide in scope, interdisciplinary in approach and located in a region of the Earth that is little studied but important to global climate (Webb et al., 1993). This project closely follows the guidelines of the USGCRP and PAGES programs and will contribute to greater coverage of the PEP-II Asian transect of PAGES/IGBP (Eddy, 1992). This study will also aid the ongoing Baikal Drilling Project efforts to recover paleoclimate change from Baikal sediments (Williams et al., 1997) by providing higher resolution records from the same region. Because small Mongolian lakes have accumulation rates approximately 5 times that of Lake Baikal (Sevastyanov et al., 1989; Colman et al., 1996), it will be possible to obtain a climate record with centennial to decadal resolution from the proposed Mongolian lake sites Through coordinated analysis of multiple climate proxies, including rock-magnetics, palynology, geochemistry, diatoms, biogenic silica and detailed lithostratigraphy, this study will provide insight into orbital and internal forcing mechanisms of the Asian Monsoon, abrupt climate change (e.g., Younger Dryas, Little Ice Age), and ecosystem change in Mongolia and provide a means of testing climate models (e.g., COHMAP). Quantification of humid and arid intervals in the sediment record will further understanding of the evolution/intensification of the Asian monsoon since the last glacial maximum and of variations in the transport of Atlantic air masses (Gasse et al., 1991; Kutzbach et al., 1993; Gasse and Van Campo, 1994; Weijian et al., 1996; Karabanov et al., submitted). Regional studies of Late Quaternary climate change are often truncated at the Mongolian border (Velichko, 1984; Winkler and Wang, 1993; Peterson et al., 1993) because political borders provide convenient boundaries for regional syntheses and paleoclimate data from Mongolia is limited (see Fig. 1 in COHMAP members, 1988; Harrison et al., 1996). However, the climate in the Mongolian region represents an important transition from the subarctic in the north (Russia) to desert in the south (Gobi of Mongolia/China). The results of the proposed study will help link the better studied region to the south (Winkler and Wang, 1993) to the existing network of lake paleoclimate records in Russia (Velichko, 1984; Harrison et al., 1996) and the new paleoclimate studies from Lake Baikal (Williams et al., 1997) along the PEP-II transect. A secondary but important objective of the proposed work is to provide geomagnetic records of direction and relative intensity (Thompson 1984; King et al., 1983; Tauxe, 1993). These geomagnetic records will fill an important gap in the global distribution of such records, contribute to a better understanding of the nature of the geodynamo, and in conjunction with the Lake Baikal geomagnetic record (Peck et al., 1996), begin to form a regional master geomagnetic curve that can be used for correlation and dating in future studies of lake and loess sediments in central Asia