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Geochemical variation at the Hawaiian hot spot caused by upper mantle dynamics and melting of a heterogeneous plume

Bianco, T.A; Ito, G.; van Hunen, J.; Ballmer, M.D.; Mahoney, J.J.

Geochemical variation at the Hawaiian hot spot caused by upper mantle dynamics and melting of a heterogeneous plume Thumbnail


Authors

T.A Bianco

G. Ito

M.D. Ballmer

J.J. Mahoney



Abstract

Geochemical variations within the young Hawaiian Islands occur in two particularly prominent forms: differences between volcanic stages and differences between the “Loa” and “Kea” subchains. These observations have been interpreted to reveal spatial patterns of compositional variation in the mantle, such as concentric zoning about the hot spot or elongate streaks along the hot spot track. Our numerical models of a hot plume of upwelling mantle that is interacting with, and melting beneath, a moving lithospheric plate suggest some of the above interpretations should be reevaluated. The mantle plume is assumed to be uniformly isotopically heterogeneous, thus without any compositional zoning. Nonetheless, our models predict geographic zoning in lava isotope composition, an outcome that is caused by differences in melting depths of distinct source components and plume-lithosphere interaction. Isotope compositions of model volcanoes that grow as they pass over the melting zone can explain some of the gross aspects of isotope variation at Hawaii. The results illustrate that chemical zoning at the surface is not necessarily a map of zoning in the mantle, and this affects further inferences about the chemical structure of the mantle.

Citation

Bianco, T., Ito, G., van Hunen, J., Ballmer, M., & Mahoney, J. (2008). Geochemical variation at the Hawaiian hot spot caused by upper mantle dynamics and melting of a heterogeneous plume. Geochemistry, Geophysics, Geosystems, 9(11), https://doi.org/10.1029/2008gc002111

Journal Article Type Article
Publication Date Nov 13, 2008
Deposit Date Aug 17, 2015
Publicly Available Date Mar 29, 2024
Journal Geochemistry, Geophysics, Geosystems
Publisher American Geophysical Union
Peer Reviewed Peer Reviewed
Volume 9
Issue 11
DOI https://doi.org/10.1029/2008gc002111
Keywords Mantle, Dynamics, Heterogeneity, Melting, Hawaii, Hot spot.

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Published Journal Article (629 Kb)
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Copyright Statement
Bianco, T. A., Ito, G., van Hunen, J., Ballmer, M. D. and Mahoney, J. J., (2008), Geochemical variation at the Hawaiian hot spot caused by upper mantle dynamics and melting of a heterogeneous plume, Geochemistry, Geophysics, Geosystems, 9(11), Q11003, 10.1029/2008GC002111 (DOI). To view the published open abstract, go to http://dx.doi.org and enter the DOI.





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