Journal article
Hf isotopic evidence for small-scale heterogeneity in the mode of mantle wedge enrichment: Southern Havre Trough and South Fiji Basin back arcs
E Todd, JB Gill, RJ Wysoczanski, J Hergt, IC Wright, MI Leybourne, N Mortimer
Geochemistry Geophysics Geosystems | Published : 2011
DOI: 10.1029/2011GC003683
Abstract
Magmas from SW Pacific back-arc basins have geochemical and isotopic signatures indicating variable mantle and subduction-derived components. Basalts from South Fiji Basin (SFB) are little influenced by subduction, but come from variably enriched mantle, resulting from mixing between enriched mantle, like FOZO, and depleted mantle, like DMM. The same components are present in the Havre Trough mantle, but Havre Trough basalts come from a mantle wedge to which a greater proportion of subduction-derived components are added. Their slab-derived components are isotopically similar to locally subducting sediment, with variable Sr and Pb from altered oceanic crust. Their compositional diversity cor..
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Awarded by Natural Environment Research Council
Funding Acknowledgements
We are especially grateful to the Captain, crew and science party of R/V Yokosuka and manned submersible Shinkai 6500, particularly Captain Fusao Saito and operations manager Yoshiji Imai. Constructive reviews by C. Chauvel and O. Ishizuka greatly improved the scope of the paper. This paper also greatly benefitted from detailed discussions with Brian Dreyer and Elizabeth K. Drewes. Samples 37D and 41D were graciously donated by Warren Smith from Scripps Institute of Oceanography (San Diego). I. C. Wright, R. J. Wysoczanski, J. A. Gamble, and M. R. Handler helped the first author in obtaining the samples used for this project and in their XRF analyses. We appreciate the technical assistance of Caroline Harris, Daniel Sampson, Rob Franks, Darren Tollstrup, and Emily Peterman at the UCSC labs. We are also grateful to Christine Laporte-Magoni, Delphine Bosch and Nick Walker for providing Nd, Sr, and Pb isotope measurements for some South Fiji Basin and Havre Trough samples. This work was funded in part by NSF award 0751600 to UCSC.