Re-evaluating plume-induced uplift in the Emeishan large igneous province

Numerical and fluid dynamic modelling predicts that mantle plumes should generate a broad domal uplift (> 1,000 km wide, 500 to >= 1,000 m high) preceding volcanism in large igneous provinces. The Emeishan large igneous province (southwest China) has been offered as the best example of plume-induced uplift, where kilometre-scale pre- and syn-volcanic relief was interpreted to develop in response to the impingement of a plume head. Here, we document voluminous mafic hydromagmatic deposits and submarine extrusions that formed during the initiation and early stages of the Emeishan large igneous province: these deposits were previously interpreted to be alluvial fan sediments shed from a pre-volcanic domal high. The abundance of such deposits-consisting of variable proportions of marine limestone and basaltic fragments-strongly suggests that the bulk of this province was emplaced at sea level. Evidence for dynamic pre-volcanic uplift as predicted by plume models is lacking, and such a lack may be the more general case. Any positive relief that developed was more likely the result of the formation of a volcanic edifice and rapid accumulation of the volcanic pile.