Physics and chemistry of mantle plumes

Hot spot volcanic chains are a fundamental feature of the Earth's crust, but their origins are still poorly understood [ Okal and Batiza , 1987]. The Hawaiian‐Emperor volcanic chain, which dominates the topography of the central Pacific ocean floor, is the best developed and most intensely studied of the known hot spot tracks. It continues to be one of the world's most important field laboratories for the study of igneous processes, plate movements, mantle convection, structure, geochemical evolution, and the properties of the lithosphere. Despite continued effort, fundamental questions regarding the composition, structure, and evolution of Hawaiian volcanos and their magma sources remain unanswered. This is largely due to the fact that only lavas representing the late stages in the evolution of the volcanos can be sampled at the surface. Most of the internal structure of the volcanos and evidence of their growth history and geochemical evolution are hidden from view. The most deeply eroded volcanos are exposed only to depths of a kilometer or so, whereas the volcanos rise some 5–15 km above the old ocean floor [ Moore , 1987].