摘要
西藏高原湖泊是我国最著名的湖群之一,面积约占全国湖泊总面积的三分之一;冈底斯山以北昆仑山以南,湖泊更为密集。本区是地球上海拔最高、面积最大的内陆湖群。其性质独特,早为中外学者所注意,但对其成因观点不一,主要有以下两种观点。
The lakes on the Xizang Plateau have long since attracted keen attention from scholars both at home and abroad,yet there is divergence in opinion as to their origin.Two distinctive views currently prevalent are as follows:(1)Some authors(E.Hungtington,1906 and E.Trinkler,1930,with the support of B.M.Cinitjen,1956)held that these lakes are sapping depressions formed by continental glaciation;(2)Others(F.Drew,1875,R.O.Oldham,1880 et al.)were of the opinion that they are formed out of dammed-up valleys.Only a few(Albert Heim,1894 and Sven Hedin,1905)touched upon such viewpoint as structural origin,but none of them gave any clear explanation to it.Investigations made in recent years have shown that both glacial and barrier lakes are generally small in size,distributing mainly at the periphery of the plateau,while other numerous lakes,large or medium,are spread all over the plateau.These lakes are mainly of structural origin as viewed principally from the following facts:1.The morphological features of structural lake:Most of the large and medium-sized lakes on the plateau are of linear or long-narrow shape.According to the morphological survey of 40 lakes in northern Xizang,the ratios of length to width are 4:1 for 30 lakes,6:1 for 26 lakes,8:1 for 9 lakes,10:1 for 5 lakes,40:1 for the most.Many lakes are deep,surrounded with steep strand-lines.The hot springs and facetted spurs are of common occurrence.2.The coincidence of lake belts with structural belts:Several lakes in the same direction often lie in zonal arrangement,inter-connected with rivers or valleys.Six latitudinal belts(trending W-E),9 longitudinal ones(N-S)and 13 oblique ones have been recognized as rift system,totaling more than 100 lakes.Different faults are often intersected to form large lakes.The above-mentioned lake belts are in turn controlled by the great rift zones of compression,tension and shearing.The principal stress field is believed to be products of the uplift of the plateau.3.The correspondence of lake-forming stage with structural stage:Statistics of the depositing time of 49 paleolakes show that the earliest lake-forming stage(Eocene epoch)is found to coincide with both the first episode of the overpowering Himalayan Movement and the time of plate collision.The develqping stage of two ancient lakes corresponds likewise to the 2nd and 3rd stages of Himalayan Movement.
作者
陈志明
Chen Zhiming(Nanjing Institute of Geography,Academia Sinica)
出处
《海洋与湖沼》
1981年第2期178-187,共10页
Oceanologia Et Limnologia Sinica
基金
科学院青藏高原综合考察成果之一
