论中—下扬子“一盖多底”格局与演化

本文是“长江中小下游及邻区构造地质图1／100万”（85－901－03）的研究成果。在区内划分出4种变质基底，结合深部资料确定4个构造—地层地体．讨论了各自组成、历史和相互拼接时代，强调了晚元古代普宁运动在地质发展中的重大意义。认为晋宁运动Ⅰ幕（1000－900Ma）是杨子区内各地体向崆岭—董岭古陆拼贴的增生期．扬子地块形成；晋宁运动Ⅱ幕（800－700Ma）是华北—扬子—华夏地块对接时代．形成古中国大陆。古生代以来为盖层发育阶段。提出中下扬子的“一盖多底”的地壳结构。纵览扬子地块地质发展和演化．可分为四个历史时期：基底发育与古中国大陆形成期；盖层发育与加里东运动；欧亚大陆形成与印支运动；陆缘—板内变形与燕山运动。

ON TECTONICS OF "POLY-BASEMENT WITH ONE COVER" IN MIDDLE-LOWER YANGTZE CRATON CHINA

his paper is partial results of introduction of "Tectonic map of Middle-Lower Yangtze River and its adjacent areas on the scale of one-millionth, compiled by Dong S. W. and Huang D. Z., with prof. Chang Y. F as the supervisor, 1995. Four kinds of metamorphic basements have been identified based on geological-and geophisical data. They are really 4 tectono-strati-graphic terrerns within the Yangtze craton. Their stratigraph, evolution and assembling time were disscussed. It was shown that late Proterozoic"Jinling Revolution" is a very active period in geological evolution. Authors believed that the first episode of Jinling revolution (1000- 900Ma) was the time for formation of Yangtze craton as a result of its terrerns accreting onto the old land of Kongling-Dongling and the second episode of Jinling revolution (800-700Ma)was assambling time among North China, Yangtze and Cathaysia cratons, and forming China Pangea.Since Palaeuzuic the sedimentary cover developed continuously the concept of tectonics of "polybasement with one cover" in Middle-Lower Yangtze craton has been set out. The geo-logical evolution of Yangtze craton could be divided into 3 stages: first stage, besement devolp-ment and China Pangea formation; second, cover sedimentary and Caledonian revolution;third, Eurasia cuntinent growth and indosinian revolution ;and the last, continental margin-interplate deformation and Sinian revolution.