MANTLE STUDIES

Convection in the Earth's mantle provides the driving force for plate- tectonic processes and the heat source for fluid transport in the Eart h's crust. Understanding the relationships between mantle composition and convection and its interaction with continental and oceanic crust provide a major challenge to modern petrologists and geochemists. This challenge can only be resolved by indirect studies, such as tomograph y and geochemical inversions on mantle-derived products, or by direct studies on rarely sampled upper mantle products in mantle xenolith sui tes and the barely accessible in situ outcrops on mantle in oceanic fr acture zones.