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《Journal of Glaciology and Geocryology》 2005-03
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Environmental Change around the Qingtu Lake since 9 500 a BP

ZHAO Qiang, WANG Nai-ang, LI Xiu-mei, CHENG Hong-yi, LI Yu, LI Gang(School of Resources and Environment,Lanzhou University, Lanzhou Gansu 730000, China)  
Investigations of geomorphology and sedimentology, and analyses of radiocarbon dates, grain size, susceptibility, content of carbonate and C/N-indicates of the sediment at the present-day closed basin (Qingtu Lake) in the terminal of the Shiyang River in arid region of China were conducted to recover the history of palaelake change since the Holocene. Qingtu Lake lies in Minqin basin in the east of the Hexi Corridor, which is located in the west edge of the East Asia monsoon. Through a field survey, the profile ZY is chosen as study object. Proxies of the Profile ZY, such as grain size, susceptibility, content of carbonate and C/N, reveal the variation of summer monsoon precipitation in the Shiyang River drainage basin during {9 500 }~ {1 100 } a BP. An abrupt event happened during {9 500 }~ {6 700 } a BP, when climate was droughty and windy, with sands depositing; During {6 700 }~ {5 800 } a BP summer monsoon strongly impacted the region, and precipitation was abundant, atmosphere was humid, lakes were deeper; During {5 800 }~ {2 700 } a BP summer monsoon became unsteady, so was water level of lakes, with frequently fluctuating climate; During {2 700 }~ {1 100 } a BP human activity increased obviously and water level of lakes declined continuously, so it is necessary to study whether the natural factors were the key to control the water level.
【Fund】: 国家重点基础研究发展规划项目(G2000048701);; 国家自然科学基金项目(40471138);; 教育部优秀青年教师科研教学奖励计划项目资助
【CateGory Index】: P467
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