The Quaternary Record of Lake-Level Oscillation and Climate Change: Lake Issyk-Kul, Kyrgyzstan, Central Asia

Am-9632967 Rasmussen，Kenneth A.Macintyre，Ian G.Smithsonian研究所标题：第四纪湖面波动与气候变化：吉尔吉斯斯坦，中亚伊塞克湖前苏联共和国的伊塞克奎湖是世界第五深湖(668m)。Issyk-Kul位于亚洲大陆海拔1600米，位于冬季西伯利亚高压和夏季西南印度低之间--即使这些主要大气要素的位置或强度的气候变化导致水分和/或温度状况的细微变化也会影响湖平面的变化，Issyk-Kul是一个闭合盆地湖泊，具有丰富的碳酸盐沉积和丰富的大规模和持续的湖平面变化的自然历史。现代湖泊水位在过去70年里下降了3米，有证据表明，在任何可能的人类干预之前很久，湖面就出现了更大的振荡。初步野外工作显示，古海岸线记录在无机和微生物成因的沿海硬地--这为晚全新世湖平面位置提供了一个可确定的代替物。该奖项支持以下研究：(1)近岸碳酸盐和晚全新世海滩沉积，以及(2)深盆地沉积和古湖泊记录。遗迹微生物的古环境意义将通过现代类比来确定。将通过岩石学技术、水泥矿物学分析以检测盐度变化以及方解石水泥的初步稳定同位素分析来评估它们作为水文状况的替代指标，以确定活的和残留的微生物的起源、生长和现代环境历史。

Abstract ATM-9632967 Rasmussen, Kenneth A. Macintyre, Ian G. Smithsonian Institution Title: The Quaternary Record of Lake-Level Oscillation and Climate Change: Lake Issyk-Kul, Kyrgyzstan, Central Asia Lake Issyk-Kui in the former Soviet Republic of Kyrgyzstan is the fifth deepest lake in the world (668 meters). Issyk-Kul is located 1600m above sea level in the Asian landmass, and is positioned between the winter Siberian High and the summer Southwest Indian Low-even subtle changes in moisture and/or temperature regime due to climate shifts in the position or intensity of these major atmospheric elements should effect changes in lake-level Issyk-Kul is a closed-basin lake with abundant carbonate sediments and a rich natural history of large-scale, and ongoing lake-level change. Modern lake level has fallen 3 meters in the last 70 years and evidence suggests even larger oscillations long before any possible human intervention. Preliminary fieldwork revealed that paleo- shorelines are recorded in coastal hardgrounds of inorganic and microbialitic origin- these provide a dateable proxy for Late Holocene lake level positions. This award supports a investigation of: (1) nearshore carbonates and Late Holocene beach deposits, and (2) the deep-basin sedimentary and paleolimnological record. Paleoenivronmental significance of the relic microbialites will be established through modern analogues. Origin, growth, and recent environmental history of the living and relic microbialites will be established through petrographic techniques, mineralogic analysis of cements to detect salinity shifts, and preliminary stable isotopes analysis of calcite cements to assess their utility as proxies for hydrologic regime.