Convection generated stress field and intra-plate volcanism

Abstract

Convection generated stresses in the lithosphere are inferable from the high degree harmonics of the geopotential. Hot spots on the earth's surface, marked by anomalous volcanism, could be surface expressions or flaws of stress concentration in tension caused by the hotter upwelling mantle convection currents. Widespread Cenozoic intra-plate volcanism in Africa, Asia, Australia and the Western United States is almost exclusively restricted to areas of the convection generated tensional stress field. This non-random distribution indicates that during Cenozoic the convection generated stresses in the lithosphere have exerted a control on the locations of these volcanic areas. In this case intraplate volcanism would be associated with tensional tectonics. The absence of volcanism in the convection generated compressional stress regimes implies that the environment of compression in the lithosphere is unfavorable for basalt magmas to migrate from the asthenosphere to the surface of the earth. Based on the results of this study, it seems reasonable to suggest that the convection generated subcrustal tensional stress field as inferred from the satellite and surface gravity data may be the genesis of the Cenozoic intra-plate volcanism.