Plume or no plume: Emeishan Large Igneous Province in Southwest China revisited from receiver function analysis

Abstract

The Late Permian Emeishan Large Igneous Province at the western margin of the Yangtze craton and eastern Tibet is popularly regarded as the signature of mantle plume impingement onto the lithosphere. In this study, we investigate the crustal structure and upper mantle discontinuities of this region by employing H–k stacking of receiver function and depth domain receiver function. Our results image the mantle transition zone. However, no vestiges of any mantle plume upwelling in this area are recorded in our results, and the region is characterized by a largely cold domain. In contrast, our data reveal a region of lower crustal delamination that coincides with the cold mantle transition zone. We therefore suggest that the delaminated lower crustal material was recycled into the upper mantle or the mantle transition zone, turning the latter into a cold domain. The delamination of the lower crust might have also led to asthenospheric upwelling and plume-like upwelling from the mantle transition zone that generated the basalts in the Emeishan Large Igneous Province.