青藏高原东缘晚新生代地质特征与古环境变化

青藏高原东缘地区发育了完整的晚新生代湖相、黄土、红土和冰川沉积系列,不同成因的沉积物记录了晚新生代以来古环境时空变迁的信息。上新世昔格达湖相沉积发育于4.2～2.6MaBP,具有9个冷—暖气候环境变化阶段。川西风尘堆积始于1.15MaBP,连续记录了14个古季风变化旋回,成都平原红土记录了1.13Ma来的5个古环境演化阶段。青藏高原东缘发育了约4.3MaBP的老冰期,第四纪时期出现了5次极端古气候事件,对应为5期冰期。

Late Cenozoic geology and paleoenvironmental change on the eastern margin of the Qinghai-Tibet Plateau.

A complete sequence of late Cenozoic lacustrine deposits,loess,red clay and glacial deposits is developed on the eastern margin of the Qinghai-Tibet Plateau.Deposits of different origins recorded rich information of paleoenvironmental change since the late Cenozoic.The Pliocene lacustrine deposits at Xigeda occurred at 4.2-2.6 Ma BP.There were nine stages of cold-warm climatic and environmental changes.Eolian deposition in western Sichuan began at 1.15 Ma BP recorded fourteen continuous paleomonsoonal cycles.Red clay in the Chengdu basin recorded five stages of paleoclimatic change since 1.13 Ma BP.There was a 4.3 Ma old glaciation on the eastern margin of the Qinghai-Tibet Plateau.During the Quaternary,there appeared five extreme paleoclimatic events,corresponding to five glaciations.