Depositional environment and hydrothermal controls on organic matter enrichment in the lower Cambrian Niutitang shale, southern China

The purpose of this research was to examine paleoenvironments, hydrothermal activity, and seawater restriction the lower Cambrian Niutitang Formation shale gas reservoir in eastern Xuefeng uplift determine factors affecting organic matter (OM) enrichment. In studied borehole Xiangan 1 well western Hunan Province, can be subdivided into Niu1, Niu2, Niu3 Members based on geological geochemical features, including trace element enrichment, lithology, fossil content. Total carbon values are variable, averaging 1.5 wt. % Niu1 Member, 12.7 Niu2 5.1 Member. Paleoclimatic changes were responsible for biota, which impacted patterns OM Climate proxy (chemical index alteration) productivity proxies (biogenic Ba, Cu/Al, Ni/Al) consistently indicate higher paleoproductivity may affected by events, whereas activity absent during deposition Hydrothermal provide nutrients silica but also enhance reducing condition water column. addition, events have possibly influenced biological survival different environments, turn increased their reproduction within early ocean production. Redox (Mo U enrichment factors) imply that deposited suboxic, euxinic, ferruginous respectively. conditions, strongly restricted conducive Cambrian.