青藏高原古新世构造岩相古地理

Paleocene tectonic lithofacies paleogeography of the Tibetan Plateau

在系统分析青藏高原及邻区古新世残留盆地类型、形成构造背景、岩石地层序列的基础上,对青藏高原古新世构造岩相古地理演化特征进行讨论:青藏高原西北部的西昆仑,北部的阿尔金、祁连、西秦岭,东北部的松潘-甘孜和南部的冈底斯陆缘弧带,以及北部的阿拉善古陆和南部的上扬子古陆和印度古陆为隆起剥蚀区。西宁-兰州、成都和班戈地区零星分布个别构造压陷湖盆。高原西部和南部为新特提斯海。南部的特提斯-喜马拉雅海区的古地理格局为萨嘎以西为残余洋盆,以东为前陆盆地。由此提出,白垩纪晚期—古新世印度板块与欧亚板块的碰撞起始于东部构造结,新特提斯洋的闭合是自东向西进行的。

Based on an integrated study of the geological maps and previous achievements, the authors analyzed the attributes, tectomc settings and lithofacies-stratigraphic sequences of the renmant basins in the Tibetan plateau. In Paleocene, the Tibetan Plateau was characterized by the erosional areas in western Kunlun, Altun, Qilian, western Qinling, Songpan-Garze and Gangdise, the Alxa and Indian ancient lands and the depressed basins （lakes and pluvial plains） in Xining-Lanzhou, Chengdu and Baingoin. There existed Neo-Tethyan remnant sea in western and southern Tibetan Plateau. It is held that the paleogeography of the Neo-Tethyan remnant sea was a remnant oceanic basin to the west of the Saga area and a foreland basra to the east of Saga during the Paleocene. The authors argue that the closure of the Neo-Tethys progressed from east to west.