中国南方大陆加里东晚期构造—古地理演化

TECTONIC AND PALEOGEOGRAPHIC EVOLUTION OF LATE CALEDONIAN IN THE SOUTH OF CHINA CONTINENT

周小进 杨帆

Zhou Xiaojin Yang Fan

中南大学, 地学与环境工程学院, 长沙, 410083 2. 中国石油化工股份有限公司, 石油勘探开发研究院, 无锡石油地质研究所, 江苏, 无锡, 214151

School of Geosciences & Environment Engineering, Central South University, Changsha, Hunan 410083, China 2. Wuxi Research Institute of Petroleum Geology, SINOPEC, Wuxi, Jiangsu 214151, China

通过对中国南方在加里东晚期(O3—S)5个时期的构造—古地理展布与演化特征分析,认为华夏陆块与扬子陆块东南缘的碰撞开始于晚奥陶世,且碰撞作用由东南向北西逐步推进,在湘赣地区发育了前陆盆地的巨厚砂岩、泥质岩沉积,江南—雪峰带和黔中地区为前陆隆起带,它们控制了扬子克拉通内盆地的沉积演化;受陆块碰撞影响,扬子克拉通东南缘由深海页岩沉积盆地向滨浅海粗碎屑岩沉积盆地转变,扬子克拉通内部则由浅海碳酸盐岩台地转化为以泥页岩沉积为主的滞流深水台内凹陷,且凹陷逐步向前陆隆起跟前迁移,以滨岸相和三角洲相的粗碎屑岩沉积为主.而川滇西部在志留纪表现为区域拉张和海侵沉积背景,具有与华南地区完全不同的构造—古地理演化格局.

Through the analysis of tectonic-paleogeographic distribution and evolutional characteristics during five periods of Late Caledonian in the south of China,a few conclusions are got as follows: Collision of Huaxia and Yangtze landmasses started from Late Ordovician and gradually developed from southeast to westnorth,where greatly thick sandstone and shale sediment of foreland basin develop in Hunan-Jiangxi Provinces.Jiangnan-Xuefeng belt and Central Guizhou zone belong to uplift behind foreland basin and control the sedimentary evolution of basins in Yangtze craton.Affected by the landmasses collision,the paleogeography in the southeast edge of Yangtze craton transforms from deep-sea to littoral or shallow sea basin,while the paleogeography inside Yangtze craton transforms from carbo-nate platform in shallow sea environment to depression with lag deposit in deep water environment.The depression inside Yangtze craton gradually moves to the front of foreland uplift,where coarse clastic rocks sediment of littoral and delta facies mainly forms.But tectonic-paleogeographic evolutional framework in the west of Sichuan-Yunnan is entirely different from the south of China,it presents the background of regional extension and marine transgression in Silurian.

中国石油化工股份有限公司科技项目(P05039)

https://doi.org/10.11781/sysydz200902128