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Oxygen isotope constraints on the structure and evolution of the Hawaiian plume

Wang, Zhengrong and Eiler, John M. and Garcia, Michael O. and Takahashi, Eiichi and Asimow, Paul D. (2010) Oxygen isotope constraints on the structure and evolution of the Hawaiian plume. American Journal of Science, 310 (8). pp. 683-720. ISSN 0002-9599. https://resolver.caltech.edu/CaltechAUTHORS:20110303-110017789

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Abstract

The oxygen isotope stratigraphy of Ko‘olau volcano, Hawaii, is constructed by analyzing olivine phenocrysts from the KSDP drill core and submarine land-slide deposits. Along with those of subaerial (Makapu‘u) Ko‘olau olivines (Eiler and others, 1996a), they span the full range of the δ^(18)OVSMOW variation previously observed in "Loa-trend" Hawaiian volcanoes (Lō‘ihi, Mauna Loa, Hualalai, and Ko‘olau), vary systematically with the stratigraphic position, and correlate with other geochemical properties of their host lavas (Tanaka and others, 2002; Haskins and Garcia, 2004; Huang and Frey, 2005; Salters and others, 2006; Fekiacova and others, 2007). These observations can be explained if the "Loa-trend" volcanoes (including Ko‘olau) are constructed of magmas made by mixing peridotite melt with variable proportions of eclogite melt derived from a mafic constituent of the Hawaiian plume having a composition resembling recent mid-ocean-ridge basalts. We present a model of this magma mixing process that simultaneously explains the correlations among oxygen isotopes, major elements, trace elements and radiogenic isotopes. Although a number of models of this kind, differing in several parameters, describe the data equally well, all statistically acceptable models require an "enriched" component with a MORB-like HREE pattern and enriched oxygen isotope composition (δ^(18)OVSMOW = 7.8-9.7‰), consistent with this component being an upper crustal (layer 1 or 2) basalt or gabbro with a low-temperature alteration history, possibly containing a small amount of sediment. Abundances of some minor elements—Ni and Ti—are not well described by this model; we show that these shortcomings are derived from the compositional assumption and operational difficulties, that is, TiO_2 content is too high in our assumed eclogite end-member, and the inversion of NiO content in the melt by the olivine addition calculation is imprecise due to the sensitivity of D_(NiO)^(olivine/melt) to the melt composition and to crystallization process. Previous studies have advocated that Hawaiian lavas were derived from partial melts of an olivine-free pyroxenite formed by reaction of eclogite-derived melt with peridotite (for example, Sobolev and others, 2005). Our study shows that the peridotite-derived and eclogite-derived melt-mixing model can explain the geochemistry of Hawaiian lavas as well, including high-Ni Ko‘olau olivines. We find that an olivine-free mantle source for Hawaiian lavas is unnecessary, although melt-rock interaction could be important in modifying melt composition. Inverting for mixing proportions and degree of melting, we estimate that the amount of recycled crust in the Hawaiian plume is <24 weight percent. Comparison of the late shield-stage "Loa-trend" (particularly Ko‘olau lavas) and "Kea-trend" (particularly Mauna Kea lavas) suggests that the geochemical diversity of Hawaiian lavas is produced by a thermally and chemically-zoned plume.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.2475/08.2010.01 DOIArticle
http://www.ajsonline.org/cgi/content/abstract/310/8/683PublisherArticle
ORCID:
AuthorORCID
Wang, Zhengrong0000-0003-3149-0236
Asimow, Paul D.0000-0001-6025-8925
Additional Information:© 2010 American Journal of Science. ZW is grateful for instructive comments from Stanley Hart, Ed Stolper, Mike Baker, George Rossman, Donald S. Burnett, Ken Farley, Fred Frey, Shichun Huang, Ilya Bindeman, Glenn A. Gaetani, Alberto Saal, Nobu Shimizu, Paul Hess, and Yan Liang. We also want to thank Dr. Michael Roden, Keith Putirka and an anonymous reviewer for their helpful reviews that significantly improve the quality of the paper.
Subject Keywords:Oxygen isotope; KSDP; olivine; Ko'olau; O'ahu; Hawaiian basalts; mantle plume
Issue or Number:8
Record Number:CaltechAUTHORS:20110303-110017789
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20110303-110017789
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:22633
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:03 Mar 2011 19:15
Last Modified:03 Oct 2019 02:39

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