华南地质2025，Vol.41Issue(4)：693-706,14.DOI:10.3969/j.issn.2097-0013.2025.04.001
鄂西盆地中二叠统孤峰组硅质来源及富硅岩石成因模式
Silicon Sources and Genetic Model of Silica-Rich Rocks in the Middle Permian Gufeng Formation of the Western Hubei Basin
摘要
Abstract
The Middle Permian Gufeng Formation in South China is an important potential stratum for future shale gas exploration.This study focuses on the dark siliceous rocks and siliceous shales with anomalously high organic matter enrichment in the Gufeng Formation of the Western Hubei Basin.Through petrological and geochemical analyses,the silica sources and genetic mechanisms are investigated to provide a theoretical basis for shale gas exploration in this area.The results indicate that the lower siliceous rock section of the Gufeng Formation in the Jiugepo profile is composed of black thin-layer siliceous rocks interbedded with shales,rich in siliceous sponge spicules and radiolarians,while the upper shale section lacks fossil.Geochemical indicators such as the Al-Fe-Mn ternary diagram,Al/(Al+Fe+Mn)ratio,and Si/(Si+Fe+Al)ratio consistently suggest that the silica-rich rocks are of biogenic origin.The sedimentary environment distinguishing diagrams of Al2O3/(Al2O3+Fe2O3)versus Fe2O3/TiO2 indicate that the study area was located on a continental margin.Combined with the lithological assemblage of the Gufeng Formation and the low Co×Mn values,it is inferred that upwelling currents persistently developed in the study area during the Middle Permian.The presence of silicified calcareous organisms in the lower shales and upper siliceous rocks of the Gufeng Formation suggests weak intermittent hydrothermal activity during the sedimentary process.The upwelling currents and hydrothermal activities provided the essential material basis for the large-scale formation of siliceous deposits in the Western Hubei Basin.Simultaneously,they transported abundant nutrients to the ocean surface,significantly enhancing primary productivity,which served as the key factor for the anomalously high organic matter enrichment in the study area.关键词
硅质页岩/上升流/热液流体/元素地球化学/孤峰组/鄂西盆地Key words
siliceous shales/upwelling/hydrothermal fluids/elemental geochemistry/Gufeng Formation/West Hubei Basin分类
天文与地球科学引用本文复制引用
龚嘉欣,韦恒叶..鄂西盆地中二叠统孤峰组硅质来源及富硅岩石成因模式[J].华南地质,2025,41(4):693-706,14.基金项目
四川省自然科学基金项目(2023NSFSC0279) （2023NSFSC0279）
国家自然科学基金项目(42272118) （42272118）
