Interaction of mantle plume heads with the Earth's surface and onset of small-scale convection

Abstract

Investigates the behaviour of a spherical blob of buoyant fluid as gravity forces it toward either a rigid horizontal boundary or a free surface. The diapir fluid is assumed much less viscous than the ambient fluid. As the diapir approaches the boundary, it collapses in the vertical and spreads horizontally while a layer of the surrounding mantle is slowly squeezed out from between the diapir and the surface. Experimental results for the thinning and lateral spreading of the buoyant fluid, and for the thinning of the squeeze layer, are given for both the case of a rigid, nonslip boundary and that of a free surface. These are compared with similarity scaling laws based on a balance beteen the buoyancy of the diapir and viscous stresses in the diapir's surroundings. -from Authors Show more