THE HIGH MOUNTAIN-DEEP BASIN SALINE ENVIRONMENT—A NEW GENETIC MODEL OF SALT DEPOSITS
Yuan Jianqi Huo Chengyu Cai Keqin (Beijing Graduate School, Wuhan College of Geology)
The major effects of the geomorphology of basins on saline deposits were for a long time neglected. In fact, many saline basins show the high mountain-deep basin feature, which is not only exemplified by some modern saline basins but also by some famous Meso-Cenozoic or even Paleozoic salt deposits which have been proved to be products of evaporation of brines in such an environment. The difference between the elevations of the deep basin and its surrounding mountains may reach a height of 1000—2000 m or even more and the differences in local climate, vegetation and hydrological conditions are prominent as well, so the surrounding mountains are favourable for the supply and transportation of salts, while the depression in a basin is favourable for the concentration and deposition of salts. Furthermore, the high mountain-deep basin geomorphology is usually controlled by deep fractures, which also facilitates the supply of salts from the depth, migration of brines in a basin and differentiation and concentration of salts. As multiple rejuvenation of fractures controlling the high mountain-deep basin geomorphology intensifies the landform, the saline basin is not stable for a long period. Recent studies of rift valleys show that saline deposits are precipitated in a certain stage of development of various rifts and are a characeritstic formation originating under an arid climate as well as the product formed in the process of plate motion. So it is closely related to tectonic movement and magmatic activity. The idea proposed in this paper is conducive to the solution of certain long-standing controversial problems on the genesis of salts; it has provided the basis for formulating a new genetic model of salt deposits and meanwhile opened up a new channel for the study of the temporal and spatial regularity governing the formation of salt deposits.