Full-Text Search:
Home|Journal Papers|About CNKI|User Service|FAQ|Contact Us|中文
《Acta Sedimentologica Sinica》 1984-03
Add to Favorite Get Latest Update

PALEOGEOGRAPHY AND PETROGRAPHICAL FACIES OF THE EARLY PERMIAN PERIOD IN CHINA

Han Keyou (Institute of Geological Exploration and Development, Sichuan Petroleum Administrative Bureau)  
The sedimentary rock area of the Early Permian system makes up about 81% of the total area of China, in which sedimentary rocks of sea facies account about 80%, To the south of 40°N, carbonates predominate with rich biota of sea facies as well as bioherm; while to the north of 40°N are the detrital rocks. The area of land facies accounts for 20% and it is chiefly distributed in the ancient land of China. The study shows that the paleotectonic and paleogeographic conditions are the main factors to control petrographical facies. The paleotectonic condition of the Early Permian is more particular. There exist two effusive rock belts in China,i. e. "Jinsha Jiang, Nu Jiang and Lancang Jiang-Kelakunlun Shan" and "South Tian Shan-Xinganlin" great rift-valleys of abyssal effusive rocks, in which the sediments are basalt, olivine basalt,andesite and basait-andesite associated with abyssal sediments of grey black bind, siliceous rock and dark grey siliceous limestone. T heir thickness is 2-6km and some even surpass 10 km. Their distribution appears as belts. The first belt is ''Jinsha Jiang.Nu Jiang and Lancang Jiang-Kelakunlun Shan" great rift-valley. It starts from the west Guangxi in the southeast, and passes westward through the valleys of "Three Jiang", that is Jinsha Jjang, Xu Jiang and Lancang Jiang and further westward through Tanggula Shan, Kelakunlun Shan up to the Pamir Plateau. It is 200-300 km wide and 3200 km long, its two ends stretch out of China. The second belt is the abyssal trough of " South Tian Shan-Xinganlin". It starts from the South Tian Shan of Xinjiang in the west and passes eastward through Liuyuan of Gansu, China-Monggolia border up to Hailar. It is 50-300km wide and 2400 km long. These two troughs cut the then architectonic framework of China into three lumps: Xizang continental segment of epeiric sea, Zhungeer relic sea basin and the ancient land of China as well as the platforms fringing epeiric sea. Owing to the characteristic features of" two belts and three lumps", the paleogeographic environment and the distribution of petrographical facies belts have to be decided as they are. The platform with the ancient land of China as its core is an open epeiric sea, except the ancient land. There are altogether 6 physical geographical areas including the ancient land and 15 petrographical facies belts; Zhungeer Basin is another physical geographical area with 3 petrographical facies belts; Xizang segmcnt is also a physical geographical area with two petrographical facies belts, the two trough arc also two physical geography areas, so there are 10 physical geographical areas with 25 petrographical facies belts in total. The brief condition of each geographical area and petrographical facies belt is as follows: 1. The South China abysmal sea and bathyal plain There are two petrographic facies in the plain. One is the black shale and siliceous rock facies of the abysmal basin in the central Hunan and the other is grey siliceous limestone and bioclastic limestone facies in the bathysal sea fringing the basin. The former is an oil and gas-bearing basin. 2. Lower Yangzi abysmal sound This sound lies between the old land of China and the old islands of Southern Yangzi Jiang Delta.The major facies is siliceous limestone intercalated with siliceous rocks. It is abundant in fossils of coral, fusulina and brachiopodas. 3. Upper Yangzi platform This is an epeiric sea platform with mild climate and thrifty organism. It is an area with better oil and gas-bearing and reservoir conditions. There are five petro-graphical facies in it. a. The bioclastic limestone and siliceous limestone facies of the epeiric sea in Sichuan, Hunan, Hubei and Guizhou with better oil and gas-bearing conditions. b. Eophyton-limestone shallow water facies in the central Sichuan. c. Xuefeng shallow water facies of white biodetritus limestone, d. Xanpan Jiang bioherm and biodetritus oolitic bank facies. The reef is composed of the framework of spongy and Rhodophyceae. e. The shallow water facies of the dolomi
Download(CAJ format) Download(PDF format)
CAJViewer7.0 supports all the CNKI file formats; AdobeReader only supports the PDF format.
©2006 Tsinghua Tongfang Knowledge Network Technology Co., Ltd.(Beijing)(TTKN) All rights reserved