Sedimentary facies of the Lower Cambrian Longwangmiao Formation in eastern Sichuan Basin and its adjacent areas
Ren Ying1,2, Zhong Dakang1,2, Gao Chonglong1,2, Dang Lurui3 Peng Ping3, Chen Weidong3, Mao Yakun1,2, Hu Xiaolin1,2
1 College of Geosciences,China University of Petroleum(Beijing),Beijing 102249 2 State Key Laboratory of Petroleum Resource and Prospecting,China University of Petroleum(Beijing),Beijing 102249 3 Chongqing Gas District,Southwest Oil and Gas Field Co.,Ltd.,PetroChina,Chongqing 400021
Abstract：Based on outcrops,logging data,seismic data and regional survey reports, the main rocks of the Lower Cambrian Longwangmiao Formation in eastern Sichuan Basin and its adjacent areas carbonate rocks(i.e., silt￣sized crystalline dolostone, grain dolostone, micritic limstone and grain limestone), and some locally-developed large sets of evaporites(gypsum rock and dolomitic gypsum rock)and mixed carbonate-clastic deposits can be seen. Four types of sedimentary facies are identified from northwest to southeast, i.e.,mixed platform,restricted platform,evaporitic platform and open platform,among which,the restricted platform is most widely developed. Generally,all the facies are distributed in a southwest-northeast trending. The mixed platform is mainly distributed in the northwestern study area,the evaporitic platform is mainly distributed on the eastern side of Huayingshan Fault in the western study area,and eastwards, the restricted platform and the open platform are developed respectively.
