摘要
通过首次对青海可可西里地区的科学考察,发现该地区第四纪冰川的发育、演化和古环境的演变,不仅受全球气候变化规律及整个青藏高原在第四纪期间的构造隆升过程的控制而具有和其它地区一致的共同规律,而且还具有独特的区域性特征。根据冰川沉积地层,更新世期间该区南北两侧的唐古拉山和昆仑山这些高大山地发育有明显的三次冰川作用,而在腹地的较低缓山地仅见到较晚的两次或一次冰川作用遗迹。其冰川发育规模以山谷冰川,山麓冰川或冰帽冰川为主,并随着高原的不断抬升有其从小→大→小的演化规律。而每次冰川作用范围均是以山地为中心展布,并没有形成统一大冰盖。此外,可可西里地区的湖泊,在更新世期间也经历了从外流水系到封闭的内陆水系的演变过程,这一过程与高原上的断块差异升降新构造活动有直接关系,同时也受到高原腹地气候逐渐变干的影响。
According to the first investigation of Quaternary glacial and lake history to the Hoh Xil region located in the interior of Qinghai-Xizang (Tibet) Plateau, it is obvious that the development and evolution of Quaternary glaciers is not only coincident with other places of the Qinghai-Xizang Plateau due to the co-control of the global climate changes and the uplift process of the plateau throughout the period of Quaternary, but also exists the distinctive regional features. During the Pleistocene, three glaciations had occurred in huge mountains of the Tanggula and Kunlun, but in the lower mountains in the centre part of the region only had taken place two or one glaciation in the later time. The developing scale and extent of glaciers were mainly limited in the high mountain areas and in the form of valley glacier, piedmont glacier and ice cap. No ice sheet existed during the Quaternary.With the intermittent uplift of the plateau in the Quaternary, the evolution of glaciation shows a pattern that the glacial scale and glaciated area of each individual glaciation from early to late Pleistocene changed from small to large, to small again. The main reason probably is that the height of most mountains was not enough to develop the large scale glaciers in the early time, and the favourable elevation of the plateau in the middle Pleistocene caused a strong plateau monsoon and south asia monsoon which brought about rich precipitation over the area. And later, its lofty elevation played a role of the barrier to obstruct water vapour into the interior of the plateau, leading to dry climate. On the other hand, lakes in the Hoh Xil area had experienced a historical process from the outflow drainage systems to the closed lake basins during the late Middle Pleistocene, which is related to the divergence movement of fault block formed by the neotectonic movement, and also affected by the drier climate.
出处
《冰川冻土》
CSCD
北大核心
1992年第4期316-324,共9页
Journal of Glaciology and Geocryology
基金
可可西里综合科学考察队成果之一
关键词
第四纪
冰川
环境
演化
the Hoh Xil area, Quaternary glaciations, glacial and environmental changes
