Discovery of Paleo-volcanic edifice and determination of its eruptive circles of Emeishan basalt in Zhaojue-Meigu Area, Sichuan Province

The geological survey revealed that several paleo-volcanic edifices related to Emeishan basalt were identified in the Zhaojue-Meigu area on the western margin of Yangtze Block, which provides an excellent window for studying their eruption cycles and modes. The rock types of paleo-volcanic edifices are mainly composed of thick basalts, small amounts of pyroclastic rocks and volcanic clastic lavas. They have the characteristics of explosive facies, lava overflow facies and volcanic depression facies. Systematic geological profile suggest that there are three rapid eruption cycles (without any interval) and 25 volcanic rhythms during the formation of the Emeishan basalt Formation. Among them, the eruption patterns of the first and third cycles are dominated by the explosive facies and lava overflow facies, while the second cycle is dominated by the overflow phase. The systematic confirmation and study of the paleo-volcanic edifices reveal the volcanic eruption pattern and cycle rhythm characteristics of Emeishan large igneous province, which provides important data for the further study of the Wupo copper deposits in the western margin of Yangtze Block.