ORIGIN OF BASALTIC AND NEPHELINITIC MAGMAS IN EARTHS MANTLE

Over the past ten years, the availability of solid-media high pressure apparatus capable of generating pressures up to 50 kbar at closely controlled temperatures (to 1,700°C) has led to a rapid acceleration of direct experimental studies of both simple systems and natural rocks under high pressure conditions. These studies have been most fruitful in elucidating possible genetic relationships among basalts and it is now possible to erect a rather complete and self-consistent model in which a peridotitic mantle, by processes of partial melting, magma segregation and further magma fractionation, may produce liquids ranging in composition from olivine melilite nephelinite to olivine tholeiite. © 1969.