关键词: 沉积盆地, 热液作用, 沉积环境, 地球化学, 有机质

Abstract:  As a material and energy exchange process between deep fluids and shallow depositional systems, hydrothermal activity exerts a crucial control on depositional environments, diagenesis, and organic matter enrichment, and shows significant spatial-temporal distribution in typical petroliferous basins of China. Based on mineralogical, lithological, and elemental-isotopic evidence, this study systematically summarizes and identifies hydrothermal mineral assemblages (e.g., dolomite, pyrite, and authigenic quartz) and geochemical fingerprints (e.g., enrichment of Fe, Mn, and light rare earth elements, Eu anomalies, and low δ18O values), and further outlines characteristic lithologic associations (e.g., siliceous rock-black shale and carbonate-organic matter interbeds). Within a regional comparative and multi-proxy framework, the geological records and paleoenvironmental changes related to hydrothermal activity in sedimentary basins are synthesized. Hydrothermal fluids alter redox gradients, supply nutrients (N, P, Fe, Si, etc.), and regulate temperature-salinity structures and water column stratification, thereby modifying salinity and local carbon cycling, which indirectly or directly affect primary productivity and organic matter preservation. Overall, hydrothermal activity exerts a dual “promotion-inhibition” effect on organic matter enrichment, with the final outcome controlled by multiple factors including temperature, fluid composition, and tectonic setting. Therefore, exploring the spatial-temporal distribution and environmental impacts of hydrothermal activity can improve our understanding of source rock formation and evolution, and provide a scientific basis for hydrocarbon potential assessment.

Key words: sedimentary basin, hydrothermal activity, sedimentary environment, geochemistry, organic matter