Lake Records of the Vegetational and Climatic History of Southwestern Siberia

西伯利亚西南部植被和气候历史的湖泊记录

• 批准号: 9975264
• 负责人: Herbert Wright
• 金额: $ 11.92万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-01-01 至 2002-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9975264&HistoricalAwards=false
• 关键词: Lake; Records; Vegetational; Climatic; History

This proposal requests support for a study of a large cluster of lakes of glacial origin occurs north of Aktash (50 20' N, 87 35' E) in the Altai Mountains of southwestern Siberia. They are located in large unforested areas at elevations of about 2000 m with conifer forest extending on adjacent ridges up to tree line above 2200 m. The lake sediments will be cored to determine by pollen analysis the vegetational and climatic history of this little known area. Included in the study will be cores from two other lakes in the mountains and one in the plain near Tomsk, obtained during exploratory field work in 1998. The focus in both the mountains and the plain is on the history of the steppe/forest border, an ecotone of proven sensitivity to climatic change as revealed by pollen analysis. In a second area northeast of the Altai Mountains in the steppe region of Khakassia (55 N, 90 E), at elevations about 200 m in a basin of the Yenesei River, the bordering ridges contain forest steppe characterized by birch and larch, with taiga conifers at elevations above about 750 m in the adjacent mountains. Fluctuations of these major ecotones will he determined by stratigraphic pollen analysis of lake sediments. Lake waters in the steppe range from fresh to saline, and their salinity history as determined by diatom analysis of their sediments will supplement pollen analysis for the reconstruction of the climatic history, for diatoms can sensitively record changes in salinity over time, as has been shown especially by extensive studies in the North American Great Plains.

这一建议要求支持一个大型集群的湖泊冰川起源的研究发生在阿克塔什（50 - 20' N，87 - 35' E）在西伯利亚西南部的阿尔泰山北部。它们位于海拔约2000米的大片无林地区，邻近山脊上的针叶林延伸至2200米以上的林木线。将对湖泊沉积物进行取样，通过花粉分析来确定这个鲜为人知的地区的植被和气候历史。这项研究将包括1998年在野外勘探工作中获得的另外两个山区湖泊和一个托木斯克附近平原湖泊的岩芯。山区和平原的重点是草原/森林边界的历史，这是一个对气候变化敏感的生态交错区，花粉分析表明。在阿尔泰山东北部的哈卡斯草原地区（北纬55度，东经90度）的第二个地区，在海拔约200米的叶尼塞河流域，接壤的山脊包含以桦树和落叶松为特征的森林草原，在海拔约750米的附近山区有针叶林。这些主要交错带的波动将通过湖泊沉积物的地层花粉分析来确定。草原上的湖泊沃茨从淡水到咸水不等，通过对沉积物进行硅藻分析确定的湖水盐度历史将补充花粉分析，以重建气候历史，因为硅藻可以敏感地记录盐度随时间的变化，这一点在北美大平原的广泛研究中尤其得到了证明。