The petrogenesis of peridotitic komatiites: Evidence from high-pressure melting experiments |
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| Authors: | MJ Bickle CE Ford EG Nisbet |
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| Institution: | Department of Earth Sciences, University of Leeds, Leeds LS2 9JTGreat Britain;Grant Institute of Geology, University of Edinburgh, Edinburgh EH9 3JWGreat Britain;Institute für Kristallographie und Petrographie, E.T.H. Zürich, CH-8092 Zürich Switzerland |
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| Abstract: | The compositions of liquidus olivines and orthopyroxenes of natural specimens of spinifex- and quench-textured peridotitic komatiites from the Belingwe Greenstone Belt, Rhodesia have been determined for pressures between 10 and 40 kbars. In conjunction with the chemical variation exhibited by these peridotitic komatiites it is concluded that the more magnesian lavas cannot be derived by concentration of olivine phenocrysts, fractional crystallisation or equilibrium partial melting. The peridotitic komatiites could evolve by polybaric assimilation and complete melting of garnet lherzolite into an initial liquid containing about 24% MgO. |
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