青藏高原极大陆型多年冻土和冰缘若干问题探讨

EXPLORATION ON SOME PROBLEMS OF THE EXTREME CONTINENTALPERMAFROST AND THE PERIGLACIAL LANDFORM IN QINZANG PLATEAU

水分条件是极大陆型多年冻土分布、发育和冰缘作用过程及其地貌类型组合的关键因素。极大陆型多年冻土下界高程最高,年平均气温最低;冰缘作用强度较弱,冰缘地貌类型单调,冰缘带下界高于多年冻土下界。

Controled by the water condition,the development and the distribution of permafrostand periglacial action, the low boundaries and the form of the periglacial landform areunique, which develop in the frigid-arid zone in Qinzang Plateau. The Russian scholars (1954), (1970) applied the conception of the maritimepermafrost and the continental permafrost.According to the viewpoint of zhou youwu(1982),the coutinental permafrost appear at the most of Qinzang Plateau and the northslopes of Ximalaya Mts,the maritime permafrost exist in the south slopes of the east part ofXimalaya Mts,the southest of Xizang and the Henduan mountain lands.Cui Zhijiu dividedthe periglacial landform of Qinzang Plateau into three types,they are the maritime,thesubcontinental and the countinental types. But the author thinks those distributions are verygeneral,they can not distinguish the features of the permafrost and the periglactal landfozm inthe semiarid,the arid and the extreme arid zones.So the countinental permafrost and theperiglacial landform should be divided into the subcontinental(semiarid), the continental(arid) and the extreme countinental (extreme arid) types. The study show that thepermafrost,the existence and the divide of the permafrost are directly controled by the verticalzonality,the latitudinal zonality and the distributions of sea and land, the elevations of thepermafrost are very different in different areas even though they are in the same latitude zonein Qinzang Plateau.