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

威廉姆斯9709343 该提案要求提供一个为期三年的奖项，对Telmen湖和Dood蒙古湖的湖泊沉积物中记录的晚第四纪古气候变化进行高分辨率的跨学科研究。 在头两年期间，将在夏季进行湖泊取芯和集水区沉积物和土壤取样方案，届时可以进入这些湖泊。 拟议的古气候研究在范围上是全系统的，在方法上是跨学科的，并且位于地球上很少研究但对全球气候很重要的区域（Webb等人，1993年）。 该项目严格遵循USGCRP和PAGES计划的指导方针，并将有助于扩大PAGES/IGBP PEP-II亚洲样带的覆盖范围（Eddy，1992年）。 这项研究还将有助于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（威廉姆斯等人，1997年），通过提供来自同一地区的更高分辨率记录。 由于蒙古小型湖泊的蓄积率约为贝加尔湖的5倍（Sevastyanov等人，1989; Colman等人，1996年），将有可能从拟议的蒙古湖站点获得百年至十年分辨率的气候记录 通过对岩石磁学、孢粉学、地球化学、硅藻、生物硅和详细的岩石地层学等多个气候代用指标的协调分析，这项研究将深入了解亚洲季风的轨道和内部强迫机制，气候突变（例如，新仙女木、小冰期）和蒙古的生态系统变化，并提供了测试气候模型的手段（例如，COHMAP）。 对沉积物记录中潮湿和干旱间隔的量化将进一步了解自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和货车Campo，1994; Weijian等人，1996; Karabanov等人，提交）。 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年; Winkler和Wang，1993年; Peterson等人，1993年），因为政治边界为区域综合提供了方便的边界，而蒙古的古气候数据有限（见COHMAP成员，1988年的图1; Harrison等人，1996年）。 然而，蒙古地区的气候代表了从北部（俄罗斯）的亚北极到南部（蒙古/中国的戈壁）的沙漠的重要过渡。 拟议研究的结果将有助于将南部研究得更好的地区（Winkler和Wang，1993年）与俄罗斯现有的湖泊古气候记录网络（Velichko，1984年; Harrison等人，1996年）和贝加尔湖的新古气候研究（威廉姆斯等人，沿着PEP-II样带。 所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发电机的性质，并与贝加尔湖地磁记录（Peck等人，1996），开始形成区域性的主地磁曲线，可用于今后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