Melting and continent generation |
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| Authors: | RK O'Nions DP McKenzie |
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| Institution: | aDepartment of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ U.K. |
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| Abstract: | The fractionated rare earth distribution in the continents requires that a small melt fraction ( 1%) separates at some stage in their development, either in the crust or in the mantle, and carries with it the continental budget of those elements. It is proposed that the very small melt fractions which control the continent's fractionated trace element budget are generated in response to lithospheric extension, plumes or aqueous fluids beneath island arcs, and emplaced into the deeper parts of the continental lithosphere. This budget is subsequently inherited by granite melts which only separate on relevant geological time scales when melt fractions reach 10% or more. The residence times of trace incompatible and major elements in the continents might be quite different. |
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