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Published February 1981 | public
Journal Article

Plate tectonics and magma genesis

Wyllie, P. J.

Abstract

The framework of plate tectonics, with active boundaries and stable plates, is the best yet devised for explaining the different types and styles of magmatic activity. The dynamic mechanisms of plate tectonics transport rock masses across fusion boundaries in three distinct types of environment and source material, associated with plate boundaries. These are divergent boundaries where mantle peridotite is transported upwards, melting to yield basalt, convergent boundaries where oceanic crust is transported downwards, melting to yield magma of intermediate SiO_2 content, and ocean-continent convergent boundaries where the lower part of continental margins are melted to yield rhyolite magma. Hot spots beneath plates, possibly generated by mantle plumes, yield basaltic magma from mantle and rhyolite magma from overlying continental crust. Subducted H_2O is involved in the generation of andesites and batholiths, and CO_2 from uncertain sources is an influential component for the generation of kimberlite and other low SiO_2, high alkali magmas below continental plates. The chemical differentiation of the earth is accomplished through magmatic processes which are a direct manifestation of convection within the mantle. Igneous petrology is now a study of processes and products firmly rooted in geophysics, and calibrated by laboratory experiments at high pressures and temperatures.

Additional Information

© 1981 Springer Verlag. This research was supported by the Earth Sciences Section of the National Science Foundation Grants EAR 76-20410 and EAR 76-20413. I thanks also Professors P. Giese and V. Jacobshagen for inviting me to present this review paper.

Additional details

Created:
August 22, 2023
Modified:
October 17, 2023