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Garnet-pyroxenite-derived end-member magma type in Kamchatka: evidence from composition of olivine and olivine-hosted melt inclusions in Holocene rocks of Kekuknaisky Volcano

Citation

Nekrylov, NA and Popov, DV and Plechov, PY and Shcherbakov, VD and Danyushevsky, LV and Dirksen, OV, Garnet-pyroxenite-derived end-member magma type in Kamchatka: evidence from composition of olivine and olivine-hosted melt inclusions in Holocene rocks of Kekuknaisky Volcano, Petrology, 26, (4) pp. 329-350. ISSN 0869-5911 (2018) [Refereed Article]

Copyright Statement

Copyright 2018 Pleiades Publishing, Ltd.

DOI: doi:10.1134/S0869591118040057

Abstract

Late Quaternary volcanoes of Sredinny Range (Kamchatka) attract geoscientists’ attention by their unusual geochemical features and geodynamic setting. They produced volcanic rocks that are enriched relative to N-MORB in most of incompatible trace elements (except HREE), including strong enrichment in large-ion lithophile elements, and show a negative Nb–Ta anomaly, which is typical for rocks formed in supra-subduction settings. However, modern subduction of the Pacific Plate does not reach the most part of Sredinny Range, as inferred by mapping of Wadati–Benioff zone or seismic tomography. We constrain the source of parental magmas for Sredinny Range volcanic rocks by combining major and trace element geochemical data for olivine and naturally quenched olivine-hosed melt inclusions for Holocene tephra layers of the Kekuknaisky field. Composition of the most magnesian olivine (Ni > 2000 ppm, Fe/Mn ≈ 75 at Mg# ~ 84–85 mol %) and geochemical characteristics of the most primitive melts (FC3MS = 0.61 ± 0.04 (2σ)) are consistent with their derivation from a pyroxenite source, while elevated LREE/HREE ratios in lavas indicate that it contained garnet. This garnet-bearing pyroxenite likely originated from the lower crust or lithospheric mantle. Its melting could have occurred due to delamination and sinking into the hotter mantle.

Item Details

Item Type:Refereed Article
Keywords:olivine, melt inclusions, pyroxenite, source, Kamchatka
Research Division:Earth Sciences
Research Group:Geology
Research Field:Igneous and metamorphic petrology
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the earth sciences
UTAS Author:Danyushevsky, LV (Professor Leonid Danyushevsky)
ID Code:144718
Year Published:2018
Funding Support:Australian Research Council (CE0561595)
Web of Science® Times Cited:6
Deposited By:CODES ARC
Deposited On:2021-06-06
Last Modified:2021-08-10
Downloads:0

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