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新生代亚洲内陆干旱化的时空演化历史及其驱动机制,是国际古环境研究的热点和重点,然而至今缺少直接来自中国境外干旱区的新生代干旱化记录.对塔吉克盆地东北缘代表性剖面的沉积相分析结果表明,该地区早新生界地层底部以副特提斯海沉积序列为主,中部为厚层风成砂与河流砂交互沉积,上部以风成黄土、砂黄土状堆积为主,顶部为河湖相沉积和风成黄土状堆积交互沉积.根据已发表的火山灰U-Pb年代、初步的古地磁年代框架及区域地层划分证据,风成砂和黄土、砂黄土状堆积物形成于晚始新世和渐新世,表明中亚的干旱环境可能从始新世晚期已经开始,其形成和发展与构造活动驱动的晚始新世副特提斯海退缩密切相关.
The history and driving mechanism of the Cenozoic aridification in inland space-time evolution are the focus and hotspot of the paleo-environmental studies in the world, but so far there is a lack of Cenozoic arid records coming directly from the arid regions outside of China. The results of sedimentary facies analysis show that the bottom of the Early Cenozoic strata in the area are mainly the Tethys sedimentary sequences, and the middle is thick sedimentary sand and river sand, the upper part is mainly aeolian loess and sandy loam. And the top is the deposition of fluvial lacustrine sediments and loess-like sediments.According to the published volcanic ash U-Pb age, preliminary paleomagnetic dating framework and regional stratigraphic division evidence, aeolian sand and loess, sandy loess sediments formed in Late Eocene and Oligocene, indicating that the arid environment in Central Asia may have started from the Late Eocene, and its formation and development are closely related to the tectonic-driven Late Eocene Side Tethys.