Geomorphological Evolution and Palaeoenvironmental Change in the Western Alashan Plateau, China

作者：Bingqi Zhu

摘要：Although neotectonic activity is considered to be the main factor of the terrain evolution of the Qinghai Tibet Plateau and its surrounding high-altitude areas,further geomorphological analysis and literature analysis are needed for the understanding of the geomorphic evolution and the Quaternary environment change of the western area of the Alxa Plateau near the northern Tibet Plateau.The purpose of this study is to investigate the distribution of site-specific geomorphic units of the landforms developed in the vast topography of Ejina Basin(Western Alxa),in order to identify the geostructural and climatic causes of the geomorphic landscape and its impact on the change of paleoenvironment.At present,the climate and hydrological conditions in Ejina are relatively monotonous and stable.In addition to tectonic dynamic factors,the most widely distributed landform in the basin is climate landform.There are both geomorphological and sedimentological anomalies of Aeolian landforms occurred in the whole basin,indicating that the underlying surface effect(retention effect)of river(Ejina River)and its related uneven ground and weak wind erosion(deflation)process in the nearby area may be the important factors controlling the formation of Ejina dunes,rather than the arid climate.It is believed that the extensive interaction between the aeolian and fluvial processes is the main mechanism of the regional geomorphic difference in Ejina Basin.According to the comparability of regional geomorphology and sedimentology,the period of the formation of relic geomorphology in the edge of Ejina Basin can be reasonably attributed to the local glacial maximum of the last glacial.The geomorphic transformation from quasi plain and desert valley to desert plain,the appearance of widely moving sand dunes and the presence of large ancient lake geomorphology all indicate that the drought index of Ejina Basin is increasing on the scale of geomorphic formation.Paleogeomorphological and chronological evidences show that the climatic and hydrolog

發文機構：Key Laboratory of Water Cycle and Related Land Surface Processes

關鍵詞：RelicLandformGeomorphicprocessesaeolian-fluvialinteractionLatePleistoceneHOLOCENEWesternAlashan

分類號： P53[天文地球—古生物學與地層學]