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Published July 3, 1981 | public
Journal Article

Hotspots, Basalts, and the Evolution of the Mantle

Abstract

The trace element concentration patterns of continental and ocean island basalts and of mid-ocean ridge basalts are complementary. The relative sizes of the source regions for these fundamentally different basalt types can be estimated from the trace element enrichment-depletion patterns. Their combined volume occupies most of the mantle above the 670 kilometer discontinuity. The source regions separated as a result of early mantle differentiation and crystal fractionation from the resulting melt. The mid-ocean ridge basalts source evolved from an eclogite cumulate that lost its late-stage enriched fluids at various times to the shallower mantle and continental crust. The mid-ocean ridge basalts source is rich in garnet and clinopyroxene, whereas the continental and ocean island basalt source is a garnet peridotite that has experienced secondary enrichment. These relationships are consistent with the evolution of a terrestrial magma ocean.

Additional Information

© 1981 American Association for the Advancement of Science. This research was supported by NASA grant NGL 05-002-069. I thank E. Stolper, A. E. Ringwood, P. Wyllie, A. Boettcher, G. J. Wasserburg, C. Allégre, S. Jacobson, L. Silver, H. Taylor, and D. Green for helpful conversations. R. Oxburgh, J. G. Schilling, P. Wyllie, and G. Ernst reviewed earlier versions of the manuscript. A. Boettcher kindly provided a most useful preprint coauthored with J. O'Neil and made some important suggestions. I thank an anonymous reviewer for his editorial comments. Contribution No. 3432, Division of Geological and Planetary Sciences, California Institute of Technology.

Additional details

Created:
August 19, 2023
Modified:
October 19, 2023