Upper-Mantle Amphiboles: A Review

J. B. Dawson and J. V. Smith
Department of Geology, University of Sheffield, S1 3JD, UK
Department of the Geophysical Sciences, University of Chicago, Illinois, 60637, USA

Abstract: Textural and chemical data are reviewed for amphiboles occurring in Cr-diopside series and Al-augite series xenoliths; as megacrysts in a variety of igneous environments; and also as minor phases in tectonic slices of upper-mantle peridotite. New data are given for pargasite and associated phases in a lherzolite from Tanzania and in kelyphite replacing garnet in a S. African kimberlite xenolith. It is concluded that only pargasites and titaniferous pargasites occurring in Cr-diopside series blocks have formed under upper-mantle conditions. Although amphibole is present in the upper mantle, as suggested by Oxburgh (1964), its relative paucity suggests it is not a major alkali and water storage site; phlogopite is a more likely candidate, particularly in the deeper parts of the upper mantle.

Mineralogical Magazine; 1982 v. 45; no. 337; p. 35-46; DOI: 10.1180/minmag.1982.045.337.04
© 1982, The Mineralogical Society
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