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

9709343 Williams这个提案要求一个为期三年的高分辨率、跨学科的研究，研究特尔门湖和杜德蒙古湖沉积物中记录的晚第四纪古气候变化。在最初的两年里，在夏季有可能进入这些湖泊的时候，将进行湖泊取样和集水区沉积物和土壤取样项目。拟议的古气候研究在范围上是全系统的，方法上是跨学科的，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）。该项目密切遵循USGCRP和PAGES项目的指导方针，并将有助于PAGES/IGBP的PEP-II亚洲样带的更大覆盖（Eddy, 1992）。这项研究还将通过提供来自同一地区的更高分辨率记录，帮助正在进行的贝加尔湖钻探项目从贝加尔湖沉积物中恢复古气候变化（Williams et al., 1997）。因为蒙古小湖泊的累积速率大约是贝加尔湖的5倍(Sevastyanov et al., 1989；科尔曼等人，1996)，将有可能从提出的蒙古湖泊遗址获得百年至十年分辨率的气候记录。通过对多种气候代用物的协调分析，包括岩石磁学、孢粉学、地球化学、硅藻、生物成因二氧化硅和详细的岩石地层学，本研究将深入了解亚洲季风、气候突变（如新仙女木期、小冰河期）、和蒙古的生态系统变化，并提供了一种测试气候模式（如COHMAP）的方法。沉积物记录中湿润和干旱间隔的量化将进一步了解末次盛冰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； Weijian等人，1996；Karabanov等人，提交）。晚第四纪气候变化的区域研究通常在蒙古边界处被截断（Velichko, 1984； Winkler和Wang, 1993； Peterson等，1993），因为政治边界为区域综合提供了方便的边界，而且蒙古的古气候数据有限（参见COHMAP成员的图1,1988；Harrison等，1996）。然而，蒙古地区的气候代表了一个重要的转变，从北部的亚北极（俄罗斯）到南部的沙漠（蒙古/中国戈壁）。拟议研究的结果将有助于将研究较好的南部地区（Winkler和Wang， 1993）与俄罗斯现有的湖泊古气候记录网络（Velichko, 1984； Harrison等人，1996）和贝加尔湖（Williams等人，1997）沿着PEP-II样带的新古气候研究联系起来。提出的工作的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;Tauxe, 1993）。这些地磁记录将填补此类记录全球分布的重要空白，有助于更好地了解地球动力学的性质，并与贝加尔湖地磁记录（Peck et al., 1996）结合，开始形成区域主地磁曲线，可用于未来中亚湖泊和黄土沉积物的对比和定年研究

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