Impact of Permian Tarim and Emeishan Large Igneous Provinces on Petroleum Systems and Gas Emissions in Tarim and Sichuan Basins

Abstract

Igneous intrusions and associated hydrothermal activities have significantly influenced petroleum systems and climate conditions at both local and global scale, especially during the Permian period. This review examines the impacts of the Tarim Large Igneous Province (TLIP) and Emeishan Large Igneous Province (ELIP) on the petroleum systems and climate outcomes in the Tarim and Sichuan basins. In the Tarim Basin, the TLIP did not coincide with source rock development, whereas the ELIP in the Sichuan Basin coincided with the formation of organic-rich shales and coals. Thermal effects from igneous intrusions played a critical role in the maturation of source rocks, inducing hydrocarbon generation through the thermal transformation of organic matter. Hydrogen produced from magma or interactions between ultramafic rock and water may play a significant role in hydrocarbon generation within petroliferous basins. Hydrothermal fluids potentially altered mature source rocks in both basins, though the extent remains uncertain. Fractures generated by igneous intrusions not only serve as reservoirs and migration pathways for hydrocarbons, but also enhance reservoir quality through hydrothermal fluid-induced dolomitization in carbonates. Intrusions can also act as barriers, impeding petroleum migration. Trapping mechanisms vary between basins: in the Tarim Basin, folds and faults resulting from intrusion-related deformation are common, while the ELIP's impact on hydrocarbon accumulation in the Sichuan Basin remains less defined. Both TLIP and ELIP released substantial greenhouse gases, yet their climate impacts differ. The ELIP is strongly associated with mass extinctions, whereas the TLIP's environmental consequences were less severe. These differences underscore the need for further research to clarify the influence of igneous intrusions on petroleum systems, source rock maturation, and climate dynamics. Understanding these interactions is crucial for unraveling their roles in geological history and global climate change.