萨拉乌苏河地区晚更新世环境演化

对萨拉乌苏河地区上更新统地层作进一步划分的基础上,本文论述本区晚更新世前期萨拉乌苏组沉积时的古地理环境为暖湿的森林草原.后期城川组主要形成于干冷的荒漠草原-荒漠环境,期间经历了一系列温凉湿润的灌丛草原-疏林草原、森林草原等环境的交替演化过程.

SEDIMENTARY-PALAEOGEOGRAPHIC ENVIRONMENT OF UPPER PLEISTOCENE STRATA AND ITS EVOLUTION IN THE SALAWUSU RIVER AREA

According to the analyses and studies of the grain-size, sporopollen, vertebrate fossils and stratum sedimentary facies in the upper pleistocene strata of the Salawusu River area, this paper discusses the palaeogeographic environment and its evolution during the late pleistocene.1.The palaeogeographic environment of the fluviolacustrine facies strata of the Salawusu Formation formed in the early stage of the upper pleistocene is warm-hummid forest steppe.2.In the late stage of the late pleistocene, the Chengchuan Formation which mainly consists of aeolian sandy deposits chiefly forms under dry-cold desert, desert steppe and in the meantime, it underwent a series of alternating evolution processes of temperate-cool's shrub steppe,sparse woods steppe and forest steppe with this environment.3.The Malan loess in the area has the same geological age as that of dry cold desert steppe.4.The Salawusu Formation is assigned to the Riss/Wurm intcrglacial age, dating back to 1.1×10⁵-7×10⁴ yrs B.P.,thereas the Chengchuan Formation andthe Malan loess are in the Wurm glacial age with an assumed date of 7×10⁴-1×10⁴ yrs B.P..