Two pulsed activities of the Emeishan large igneous province in southwestern China inferred from dolomite U-Pb geochronology and significance

Abstract

The Emeishan large igneous province (ELIP) was a major geological event that took place around the Middle−Late Permian boundary. The major episode of the ELIP is generally considered to have occurred at 260−259 Ma, although an increasing number of geological data have suggested that multiple episodes of magmatic activity might have occurred. Here we report a study of a Lower Permian dolomite whose formation was influenced by the ELIP in the Sichuan Basin of southwestern China. Results show two new pulsed activities at 273.2 ± 9.7 Ma to 269.1 ± 12.0 Ma (ELIP-I) and 263.2 ± 10.3 Ma to 258.7 ± 8.1 Ma (ELIP-II). The two stages of the ELIP magmatism and thermal activity controlled the regional tectonic, sedimentary, and diagenetic evolution and exerted a profound influence on the oil and gas reservoirs, source rocks, and lithofacies paleogeography. This study is the first to interpret the timing of the ELIP from analysis of hydrothermal dolomite and provides new clues and data for improving our understanding of the dynamic formation mechanism and Earth system of the ELIP.