华南地质2026，Vol.42Issue(4)：634-647,14.DOI:10.3969/j.issn.2097-0013.2026.04.006
鄂西P2/P3界线特征、锆石U-Pb定年及其对构造演化与页岩气勘探的启示
Characteristics of the P2/P3 Boundary,Zircon U-Pb Geochronology and Its Implications for Tectonic Evolution and Shale Gas Exploration in Western Hubei
摘要
Abstract
[Objective]The boundary between the Middle Permian Gufeng Formation(P2g)and the Upper Permian Longtan Formation(P3l)is a key stratigraphic marker for identifying the Dongwu Movement in western Hubei.Determining the position of the Middle-Upper Permian boundary in this area and revealing the manifestations of the Dongwu Movement are of great significance for shale gas exploration in the region.[Methods]Typical sections in Enshi,Hubei Province were selected for detailed geological section measurement.Combined with zircon U-Pb dating,sediment grain size analysis and clay mineral assemblage analysis,the boundary characteristics between the Gufeng Formation and the Longtan Formation were systematically investigated.[Results](1)A para-unconformity exists between the Gufeng Formation and the Longtan Formation.The weighted average zircon U-Pb age of the volcanic event layer at the top of the Gufeng Formation is 259.98±1.21 Ma,corresponding to the end of the Guadalupian Epoch,which is highly consistent with the latest published age of the Middle-Upper Permian boundary by the International Commission on Stratigraphy.(2)Two types of weathering crust,namely ferromanganese and argillaceous weathering crusts,are developed near the boundary with obviously different spatial distributions,indicating differential tectonic uplift during the Dongwu Movement.(3)The grain size and mineral assemblages of clastic sediments in the Longtan Formation show characteristics of mixed provenances,and the lithofacies gradually change from the peripheral paleo-uplifts to the depocenter.[Conclusions]This study defines the precise age and identification markers of the Middle-Upper Permian boundary in Western Hubei.It provides new evidence for analyzing the tectonic attributes and temporal-spatial evolution of the Dongwu Movement in this region,and lays a stratigraphic and tectonic foundation for the evaluation of shale gas exploration potential of the Gufeng Formation.关键词
鄂西地区/孤峰组/龙潭组/锆石U-Pb定年/东吴运动/页岩气勘探Key words
Western Hubei/Gufeng Formation/Longtan Formation/zircon U-Pb dating/Dongwu Movement/shale gas exploration分类
天文与地球科学引用本文复制引用
石先滨,翁茂芝,段先锋,罗红,孙腾,文剑航,周晓宁,余江浩..鄂西P2/P3界线特征、锆石U-Pb定年及其对构造演化与页岩气勘探的启示[J].华南地质,2026,42(4):634-647,14.基金项目
中国地质调查局项目(12120113061800) （12120113061800）
