Late Permian Emeishan Flood Basalts in Southwestern China

Abstract

Current debates over mantle plumes are centered on three assumptions namely: (1) cylindrical thermally anomalous materials which arise from the core mantle boundary; (2) high temperature of mantle plumes; (3) mantle plumes are stationary. A full test of the validity of these assumptions requires a comprehensive evaluation using techniques including high resolution seismic tomography, petrology and paleomagnetism. It is argued in this paper that the plume hypothesis can fairly well explain first order geologic observations. Geoscientists against the plume hypothesis often tend to over emphasized some details that may be also influenced by other factors, in addition to mantle plumes. Five criteria can be used to identify ancient mantle plumes: (1) crustal uplift prior to volcanism; (2) dyke swarms; (3) volcanic chain; (4) physical characteristics of volcanism and (5) chemical characteristics of plume derived basalts. Our investigation shows that at least three, and perhaps, four of these criteria are met for the Emeishan large igneous province, suggesting that a mantle plume played a central role in the generation of the Emeishan basalts.