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

9709343威廉姆斯这项提议要求获得一项为期三年的奖项，用于对特尔曼湖和多德蒙古湖的湖泊沉积物中记录的第四纪晚期古气候变化进行高分辨率的跨学科研究。在头两年，将在夏季进行湖泊取心和集水沉积物和土壤采样计划，届时可以进入这些湖泊。拟议的古气候研究是全系统范围的，方法是跨学科的，并且位于地球上一个研究很少但对全球气候很重要的区域(Webb等人，1993)。该项目严格遵循USGCRP和PAGE计划的指导方针，将有助于更多地报道PEP-II亚洲横断面的PAGE/IGBP(Eddy，1992)。这项研究还将通过提供同一地区更高分辨率的记录，帮助正在进行的贝加尔湖钻井项目从贝加尔湖沉积物恢复古气候变化的努力(Williams等人，1997年)。由于蒙古小湖泊的堆积速率大约是贝加尔湖的5倍(Sevastyanov等人，1989；Colman等人，1996)，通过协调分析包括岩石磁学、孢粉学、地球化学、硅藻、生物硅和详细的岩石地层学在内的多个气候指标，将有可能从拟议的蒙古湖泊地点获得百年到十年分辨率的气候记录，这项研究将深入了解亚洲季风的轨道和内部强迫机制、突然气候变化(如年轻仙女木、小冰期)和蒙古生态系统变化，并提供一种测试气候模型(如COHMAP)的手段。对沉积物记录中的潮湿和干旱间隔进行量化，将进一步了解自上次冰川盛期以来亚洲季风的演变/加强以及大西洋气团输送的变化(Gasse等人，1991；Kutzbach等人，1993；Gasse和Van Campo，1994；魏健等人，1996；Karabanov等人，提交)。关于晚第四纪气候变化的区域研究往往在蒙古边界被截断(Velichko，1984；Winkler和Wang，1993；Peterson等人，1993)，因为政治边界为区域合成提供了方便的边界，而来自蒙古的古气候数据有限(见COHMAP MAP成员，1988；Harrison等人，1996)。然而，蒙古地区的气候代表着从北部亚北极(俄罗斯)到南部沙漠(蒙古戈壁/中国)的重要过渡。拟议研究的结果将有助于将南部研究较好的地区(Winkler和Wang，1993)与俄罗斯现有的湖泊古气候记录网络(Velichko，1984；Harison等人，1996)以及沿PEP-II样带的贝加尔湖(Williams等人，1997)新的古气候研究联系起来。拟议工作的一个次要但重要的目标是提供方向和相对强度的地磁记录(Thompson 1984；King等人，1983；Texe，1993)。这些地磁记录将填补这类记录全球分布的一个重要空白，有助于更好地了解地球发电机的性质，并与贝加尔湖地磁记录(Peck等人，1996)一起开始形成区域主地磁曲线，可用于今后对中亚湖泊和黄土沉积物的对比和测年

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