[SGC49-10] Bulk Os isotopes and Highly shiderophile elemens abundance of Hawaiian mantle xenoliths
Keywords:Hawaii, Xenolith, Os isotope
Whole-rock samples of the peridotite xenoliths from the SLC and Kaula Island possess similar petrological and geochemical characteristics regarding the variations in the abundances of major and trace elements as well as the HSE ratios. The variations of these parameters (e.g., Ca, Al, Yb, V, and Pd/Ir) show broad positive correlations against the whole-rock 187Os/188Os ratios (0.115-0.128), indicating that the peridotites are residues of variable degrees of melting. Unlike global abyssal peridotites, a substantial proportion of the mantle xenoliths from the SLC and Kaula Island (36%) are characterized by unradiogenic 187Os/188Os ratios (< 0.12). Moreover, the unradiogenic samples show trends clearly resolvable from those of the global abyssal peridotites in the diagrams of Ca, Al, Yb, V, and Pd/Ir versus 187Os/188Os ratios. Taken together, it is conceivable that the peridotite xenoliths from the SLC and Kaula Island represent ancient depleted components in a chemically heterogeneous mantle plume as proposed by previous studies [4, 5].
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