Source and tectonic background analysis of the Sinian Doushangtuo Formation in Well WT1 in Kaijiang area,Sichuan Basin
He Yuan1, Wen Long1, Luo Bing1, Zhou Gang1, Wang Qi-Yu2, Li Kun-Yu1, Jia Min1, Chen You-Lian1, Bai Xiao-Liang1
1 Exploration and Development Research Institute,PetroChina Southwest Oil & Gas Field Company,Chengdu 610041,China; 2 Chengdu Center of China Geological Survey,Chengdu 610081,China
Abstract：The clarification of the geologic tectonic background of the Doushantuo Formation in Well WT1 in Kaijiang area,Sichuan Basin,and reconstruction of its archetypal sedimentary basin,will provide scientific basis for the palaeogeography reconstruction and the further exploration and development of oil and gas. Petrology,petrogeochemistry and U-Pb geochronology of detrital zircons were used to analyze the provenance of Doushantuo Formation. The petrogeochemical results show the source rocks of Doushantuo Formation in Well WT1 are intermediate-basic volcanic rocks and have undergone moderate chemical weathering. The detrital zircon U-Pb ages mainly record three stages of tectonic magmatic activity,including 915-850Ma,794-714.5Ma and 622-700Ma,which are mainly related to the disintegration and evolution of the Rodinia supercontinent in the northern margin of Yangtze Craton and its adjacent area. The intermediate-basic volcanic rocks in this tectonic background are the main source of the Doushantuo Formation deposition in Well WT1. The results show that the Doushantuo Formation in Kaijiang area of Sichuan Basin is developed in the extensional tectonic setting and belongs to the craton inner rifting basin deposits,which is favorable for the development of hydrocarbon source rocks. At the same time,this work provides important chronologic evidence for the break up evolution of the Rodinia supercontinent. This study is of great scientific significance in understanding of the geological structure,tectono-sedimentary evolution and the strategic development of oil and gas exploration in the Sichuan Basin.
He Yuan,Wen Long,Luo Bing et al. Source and tectonic background analysis of the Sinian Doushangtuo Formation in Well WT1 in Kaijiang area,Sichuan Basin[J]. JOPC, 2021, 23(4): 683-702.
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