Origins of the hydrothermal dolomites in Middle Permian, Sichuan Basin (SW China): Implication for the relationship with the Emeishan Large Igneous Province.

ABSTRACT: The Middle Permian dolomites in the Sichuan Basin (SCB) of China include several replacive phases and pore-filling saddle dolomite (Rd3 and Sd). This study investigates the origin of the main hydrothermal phases (Rd3 and Sd), which are composed of medium to coarse, non-planar crystals and are heterogeneously distributed, with abundance decreasing sequentially from the southwestern (SW) to the central and northwestern (NW) SCB. A comprehensive petrographic and geochemical analysis reveals a systematic spatial gradient across the basin: fluid inclusion temperatures, salinities, dolomite ordering degrees, and calculated δ¹⁸Ofluid values all increase from the NW to the SW. This trend reflects a transition from a distal, rock-buffered diagenetic system in the NW, dominated by heated Permian sea

SUBMITTER: Zheng H 

PROVIDER: S-EPMC12633893 | biostudies-literature | 2025

REPOSITORIES: biostudies-literature