The sedimentary evolution characteristics of continental shelf facies black shale of Lower Cambrian Shuijingtuo Formation in Northeast Chongqing
Zhu Yu1,2,3,4, Zhang Fan1, Li Shaorong2,3,4
1. Southwest Petroleum University， School of Geoscience and Technology， Chengdu 610500；
2. Key Laboratory of Shale Gas Exploration， Ministry of Land and Resources， Chongqing Institute of Geology and Mineral Resources， Chongqing 400042；
3. Chongqing Engineering Research Center for Shale Gas Resource & Exploration， Chongqing Institute of Geology and Mineral Resources， Chongqing 400042；
4. Chongqing Shale Gas Research Center of State Key Laboratory of Petroleum Resource and Prospecting， Chongqing 400042
The northeast area of Chongqing is in the joint part of thrust—fold belt of Mesozoic Sichuan foreland basin and southern margin of Yangtze landmass， structurally forming asymmetric anticline and syncline which are dense in E-W trending and parallel in general. Lower Cambrian Shuijingtuo shale developed in stagnant marine basin formed by continental margin， intercratonic depression and foreland flexure with deep buried depth， varying lithofacies associations. In this paper， we make use of strata combination， lithology， fossil， marker bed， formation thickness and geochemical indicators to divide Shuijingtuo shale into two third—order sequences（SQ1 and SQ2）， and each sequence is further divided into two system tracts， TST and HST. Through analyzing sedimentary facies and the distribution， combining well tie profiles， black shale distribution and geochemical elements， the results show that Lower Cambrian Shuijingtuo Formation are neritic deep shelf deposit， and shallow shelf deposit as well as arenaceous shelf deposit.
Zhu Yu,Zhang Fan,Li Shaorong. The sedimentary evolution characteristics of continental shelf facies black shale of Lower Cambrian Shuijingtuo Formation in Northeast Chongqing[J]. Chinese Journal of Geology, 2016, 51(3): 961-977.