High μ (HIMU) ocean island basalts in southern Polynesia: New evidence for whole mantle scale recycling of subducted oceanic crust
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In this paper, major elements, trace elements, and Pb isotopic compositions were determined for ocean island basalts (OIBs) from Polynesia in the southern Pacific in order to document the chemical characteristics of OIB sources and to understand their origin.Abstract:
Major elements, trace elements, and Pb isotopic compositions were determined for ocean island basalts (OIBs) from Polynesia in the southern Pacific in order to document the chemical characteristics of OIB sources and to understand their origin. High μ (HIMU: μ=238U/204Pb) basalts, which have distinctly high Pb isotopic ratios, have systematically different compositions from non-HIMU basalts; HIMU basalts are more enriched in Fe2O3*, MnO, and CaO and more depleted in SiO2, K2O, P2O5, Ni and incompatible trace elements than non-HIMU, except for Nb. Major element characteristics of HIMU basalts suggest that the HIMU source is more fertile, i.e., more enriched in a basaltic component, than non-HIMU sources. This is consistent with the suggestion that subducted oceanic crust may contribute to the formation of the HIMU reservoir. Relative depletion of incompatible trace elements in HIMU is consistent with involvement of sedimentary components in non-HIMU sources. However, enrichment of Nb relative to other incompatible elements in HIMU cannot be explained by simple addition of the crustal component nor partial melting processes in the upper mantle, implying that lower mantle processes may contribute to the formation of the HIMU source.read more
Citations
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FOZO, HIMU, and the rest of the mantle zoo
TL;DR: In this article, the American Geophysical Union published a paper on Geochemistry Geophysics Geosystems 6 (2005): Q05007, doi:10.1029/2004GC000824.
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Trace element transport during dehydration processes in the subducted oceanic crust: 1. Experiments and implications for the origin of ocean island basalts
TL;DR: In this paper, it was shown that the very high Pb isotopic ratios observed in some ocean island basalts, known as HIMU, can be readily achieved by incorporation of ancient subducted crust into their mantle source.
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High-pressure partial melting of garnet pyroxenite: Possible mafic lithologies in the source of ocean island basalts
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Anhydrous partial melting experiments on MORB-like eclogite: Phase relations, phase compositions and mineral-melt partitioning of major elements at 2-3 GPa
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Large igneous provinces: crustal structure, dimensions, and external consequences
Millard F. Coffin,Olav Eldholm +1 more
TL;DR: In this article, the authors compile all known in situ LIPs younger than 250 Ma and analyze dimensions, crustal structures, ages, and emplacement rates of representatives of the three major LIP categories: Ontong Java and Kerguelen-Broken Ridge oceanic plateaus, North Atlantic volcanic passive margins, and Deccan and Columbia River continental flood basalts Crustal thickness ranges from 20 to 40 km, and the lower crust is characterized by high (70-76 km s?1) compressional wave velocities.