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Quest for low-degree mantle melts
journal contribution
posted on 2023-05-22, 01:43 authored by Trevor FalloonTrevor Falloon, Green, DH, O'Neill, HSTC, Ballhaus, CGBaker et al. report an experimental study at pressures of 1 GPa (1,000 million Pa) to determine the composition of a silicate melt produced at anhydrous, near-solidus conditions from a lherzolite composition. They obtained a composition at 1,250 °C with -57% Si02 and -5.7% Na20, which is 'andesitic' in the sense of its low normative diopside (5% ), high normative hypersthene (> 15%) and high normative plagioclase (> 75%, andesine). These results conflict with earlier conclusions that anhydrous melts of fertile lherzolite at 1 GPa are basaltic, with ~15-20% normative diopside, > 10% normative olivine and, at low degrees of melting, nephelinenormative. From our own experience and experimental tests, we suggest the following possible explanations for the observations of Baker et al.
History
Publication title
NatureVolume
381Issue
6580Pagination
285ISSN
0028-0836Department/School
School of Natural SciencesPublisher
Nature Publishing GroupPlace of publication
London, UKRights statement
Copyright 1996 Nature Publishing groupRepository Status
- Restricted