地质学报（英文版）2002，Vol.76Issue(3)：283-291,9.
Quaternary Lake Deposits of Nam Co, Tibet, with a Discussion of the Connection of Nam Co with Ring Co-Jiuru Co
Quaternary Lake Deposits of Nam Co, Tibet, with a Discussion of the Connection of Nam Co with Ring Co-Jiuru Co
摘要
Abstract
Shorelines are widespread and lake deposits and lake geomorphology are well developed on the northern Tibetan Plateau. Through field observations of lacustrine deposits of Nam Co-the highest and largest Quaternary lake in Tibet, the authors found four-step shore terraces composed of sands and clays with well-developed horizontal bedding and 3-12 m, 15-22 m, 25-30 m and 35-45 m higher than the lake surface respectively, lacustrine deposits resting on the bedrocks and 60-150 m higher than the lake surface, and up to ~50 levees composed of oblate lakeshore gravels. Moreover they found lacustrine and lakeshore deposits making up the terraces and levees on the bottoms of wide dividing valleys connecting Nam Co with the Rencoyuema, Rencogongma and Jiuru Co northwest of Nam Co (the valley bottoms are 20 m, 90 m and 60 m higher than the above-mentioned three lakes) and on slopes north of it, i.e. terraces II and III of Nam Co. Thus they confirm that Nam Co and Ring Co-Jiuru Co had connected with each other several times, i.e. formed a unified large lake several times, rather than had been different lakes connected only by river channels. From indications such as the distribution of the highest shoreline and lake deposits and geomorphology, the authors conclude that the total area of the old large lakes on the northern Tibetan Plateau is a few times larger than that of the modern lakes and that the last-stage old large lakes formed in the interglacial interval of the last glaciation.关键词
Tibet/Nam Co/Quaternary/lake deposits/old large lakeKey words
Tibet/Nam Co/Quaternary/lake deposits/old large lake分类
天文与地球科学引用本文复制引用
朱大岗,赵希涛,孟宪刚,吴中海,吴珍汉,冯向阳,邵兆刚,刘琦胜,杨美玲..Quaternary Lake Deposits of Nam Co, Tibet, with a Discussion of the Connection of Nam Co with Ring Co-Jiuru Co[J].地质学报（英文版）,2002,76(3):283-291,9.基金项目
This research represents the stage results of the large-scale land and resources survey project "Investigation of the Quaternary Environmental Evolution of the Nam Co area in Tibet" (No. DKD2001006) and "1∶250000 Regional Geological Survey of Damxung" (No （No. DKD2001006）
