成果归属作者：

高平

成果归属机构：

能源学院

作者：

Li, Jinku ; Gao, Ping ; Xiao, Xianming ; Lash, Gary G. ; Li, Shuangjian ; Liu, Wei

单位：

China Univ Geosci Beijing, Sch Energy Resources, Beijing 100083, Peoples R China;China Univ Geosci Beijing, Frontiers Sci Ctr Deep time Digital Earth, Beijing 100083, Peoples R China;State Univ New York Fredonia, Dept Geol & Environm Sci, Fredonia, NY 14063 USA;SINOPEC, Petr Explorat & Prod Res Inst, Beijing 102206, Peoples R China

关键词：

BLACK SHALES; NIUTITANG FORMATION; REDOX ENVIRONMENTS; SEDIMENTARY-ROCKS; EARLY DIAGENESIS; XIAOTAN SECTION; RICH SEDIMENTS; CARBON-ISOTOPE; BARIUM FLUXES; SICHUAN BASIN

摘要：

Early Cambrian Earth history witnessed significant changes in marine environments and biological evolution contemporaneous with extensive accumulation of organic-rich shale. However, major factors controlling hyperenrichment of organic matter (OM) of lower Cambrian shale deposits remain controversial. Black shale of the lower Cambrian Niutitang Formation (NTT) of the marginal Yangtze Platform (South China) deposited during the Cambrian middle Age 2 are especially organic-rich, with total organic carbon (TOC) concentrations of as much as 13.0 wt%. Geochemical evidence suggests that cool, dry paleo-climatic conditions that prevailed on the Yangtze Platform during the Cambrian Fortunian-late Age 2, induced vigorous coastal upwelling. Paleo-productivity level assessments indicate that the magnitude of primary productivity contemporaneous with deposition of the NTT shale deposits exceeded that of modern upwelling systems (e.g., Peruvian Margin). The widespread occurrence of phosphate nodules within these deposits and decreased Co-EF x Mn-EF values of associated lower Cambrian black shale successions deposited along the margin of the Yangtze carbonate platform suggest extensive coastal upwelling. Widespread and strong coastal upwelling in tandem with elevated surface water primary productivity and anoxic (even euxinic) bottom water conditions are manifested by deposition of OM hyper-enriched black shale during Cambrian Fortunian to middle Age 2 time. However, weakened seasonal upwelling that appears to have prevailed during the late Cambrian Age 2 was accompanied by accumulation of NTT shale deposits of diminished TOC content. In summary, this study provides robust evidence of extensive coastal upwelling along the marginal Yangtze Platform during early Cambrian time that favored accumulation of OM hyper-enriched shale. These results help to elucidate the distribution of high-quality lower Cambrian natural gas source rocks in South China.

基金：

National Natural Science Foundation of China [42030804, 42272140]; CNPC Innovation Fund [2022DQ02-0107]; Deep-time Digital Earth Science and Technology Leading Talents Team Funds for the Central Universities for the Frontiers Science Center for Deep-time Digital Earth, China University of Geosciences (Beijing) (Fundamental Research Funds for the Central Unive [2652023001]

语种：

英文

DOI：

10.1016/j.palaeo.2024.112569

来源：

PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY,2024():.

出版日期：

2024-12-15

提交日期：

2024-11-19

引用参考：

Li, Jinku; Gao, Ping; Xiao, Xianming; Lash, Gary G.; Li, Shuangjian; Liu, Wei. Widespread coastal upwelling along the marginal Yangtze Platform (South China) during the early Cambrian: Implications for hyper-enrichment of organic matter[J]. PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY,2024():.