Tomanikova, L, Savov, IP orcid.org/0000-0003-4218-4365, Harvey, J orcid.org/0000-0002-0390-3438 et al. (4 more authors) (2019) A limited role for metasomatized sub-arc mantle in the generation of boron isotope signatures of arc volcanic rocks. Geology, 47 (6). pp. 517-521. ISSN 0091-7613
Abstract
Metasomatized sub-arc mantle is often regarded as one of the mantle reservoirs enriched in fluid mobile elements (FME, e.g. B, Li, Cs, As, Sb, Ba, Rb, Pb) which, when subject to wet melting, will contribute to the characteristic FME-rich signature of arc volcanic rocks. Evidence of wet melts in the sub-arc mantle wedge is recorded in metasomatic amphibole-, phlogopite- and pyroxene-bearing veins in ultramafic xenoliths recovered from arc volcanoes. Our new B and δ11B study of such veins in mantle xenoliths from Avachinsky and Shiveluch volcanoes, Kamchatka arc, indicates that slab-derived FME, including B and its characteristically high δ11B, are delivered directly to a melt that experiences limited interaction with the surrounding mantle before eruption. The exceptionally low B contents (from 0.2 to 3.1 µg g-1) and low δ11B (from -16.6 to +0.9 ‰) of mantle xenolith vein minerals are, instead, products of fluids and melts released from the isotopically light subducted and dehydrated altered oceanic crust (AOC) and, to a lesser extent, from isotopically heavy serpentinite. Therefore, melting of amphibole-, and phlogopite-bearing veins in metasomatized mantle wedge cannot alone produce the characteristic FME geochemistry of arc volcanic rocks, which require a comparatively large, isotopically heavy and B-rich serpentinite-derived fluid component in their source.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2019 The Authors. This is an open access article under the terms of the Creative Commons Attribution License (CC-BY). |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Inst of Geophysics and Tectonics (IGT) (Leeds) |
Funding Information: | Funder Grant number NERC NE/M000427/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 03 Apr 2019 10:13 |
Last Modified: | 25 Jun 2019 15:58 |
Status: | Published |
Publisher: | Geological Society of America |
Identification Number: | 10.1130/G46092.1 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:144318 |