浑善达克沙地的形成时代与成因初步研究

PRELIMINARY STUDIES ON FORMATIVE AGE AND CAUSES OF OTINDAG SANDY LAND IN CHINA

根据较广泛的含风成砂地层的野外调查与有关室内样品分析结果，浑善达克沙地至少形成于晚第三纪。当时受暖干亚热带动力高压控制和较弱东亚季风影响，出现温暖干旱荒漠、半干旱草原及森林草原之间的环境变化，形成亚热带红色季风性沙漠沉积。第四纪，受东亚季风及其变迁影响，环境在温带荒漠草原至森林草原之间波动变化，出现一系列沙丘活化、沙漠扩展与沙丘固定、沙漠收缩的波动过程，形成温带黄色季风型沙漠沉积。

The results of comprehensive field investigation and some relative sample tests of strata containing eolian sand showed that the Otindag Sandy Land was formed as far as in the Later Tertiary Period at least. During the period, chiefly controlled by subtropical warm/dry high pressure and weakly influenced by East Asian monsoon, the sandy land experienced fluctuational environmental change among warm/arid desert,warm/semiarid steppe and warm/semihumid forest steppe, and was deposited with monsoonal red desert deposits. In the Quaternary, mainly affected by the East Asian monsoon and its variation, the sandy land experienced a series of fluctuations among dune mobilization, desert expandation and dune fixation or desert contraction. The environments changed between temperate desert steppe and forest steppe, the sediments was temperate monsoonal yellow desert types.