青藏高原中东部第四纪冰碛物暴露年龄的测定及其意义

Exposure ages of moraines in the eastern and central Qinghai-Tibet plateau and their significance.Earth Science Frontiers

青藏高原上大面积的冰盖通常会对亚洲乃至全球气候产生深远的影响。青藏高原第四纪冰川形成的时间和范围成为人们关注的热点。本研究利用就地成因的宇宙核素暴露年龄测定方法，对唐古拉山和理塘地区的第四纪冰碛物进行了^10Be、^28Al和^21Ne暴露年龄测定，首次获得了青藏高原的第四纪冰川核素暴露年龄。三种核素暴露年龄的一致性显示每期冰碛物沉积有一个确定的暴露时期，测试结果表明唐古拉山和理塘地区出现了两期第四纪冰期，一期形成于距今1．6～8万年，另一期形成于距今16-18万年。

Large glacial sheets in the Qinghai-Tibet plateau have an important effect on both Asian and global climate.. There is much interest in the timing and duration of the Quaternary glacial in the plateau. Using cosmogenic determinations we have obtained the first in-situ morainal exposure ages from the glacial moraine in the Tanggula mountain and Litang. The three kinds of exposure ages from ^10 Be,^26 Al, and 21 Ne are similar. According to our dating, there were two glaciations, one formed between 16-80 ka B. P. , and the other between 160-180 ka B. P.