Role of slab-derived fluids in the Emeishan Large Province

The role of fluids in the formation of large igneous provinces (LIPs) remains a topic of debate. The Emeishan Large Igneous Province (ELIP) in southwestern China, with a large volume of mafic intrusive and extrusive suites, provides an ideal window to explore this enigma. We predict the bulk rock characteristics of basalt and diabase in the ELIP using a model trained by machine learning methods (random forest [a collection of decision trees that work together to make predictions]) and using global data sets of basalts in diverse settings. The results indicate that the basalts and diabases in the ELIP generally exhibit some affinity to island arc basalt. Furthermore, there is a spatial decline in composition from west to east in the northern part of the ELIP and generally from south to northwest and northeast along the southern margin of the Yangtze craton in the southern part of the ELIP. This pattern may be linked to the subduction of oceanic lithosphere around the Yangtze craton during the Neoproterozoic. Our study reveals the interaction between the Neoproterozoic subducted slab and mantle plume, and highlights the contribution of fluids from the slab in the formation of the ELIP.