SEISMIC EVIDENCE FOR A FOSSIL MANTLE PLUME BENEATH SOUTH-AMERICA AND IMPLICATIONS FOR PLATE DRIVING FORCES

A teleseismic travel-time study reveals the presence of a fossil plume in the deep upper mantle beneath Brazil, which has apparently remaine d geographically fixed with respect to the overlying continent despite thousands of kilometres of plate motion. This result implies that the upper mantle and lithosphere beneath South America have remained coup led since the breakup of Gondwanaland and may provide an answer to the long-standing question of what forces drive continental plates.