Origin and temporal evolution of Koʻolau Volcano, Hawaiʻi: Inferences from isotope data on the Koʻolau Scientific Drilling Project (KSDP), the Honolulu Volcanics and ODP Site 843

Double layering of a thermochemical plume in the upper mantle beneath Hawaii

“…1 versus 6). The predicted difference in origin for the rejuvenated-stage and arch volcanism (i.e., from the plume outskirts) versus shield-stage volcanism (i.e., from the plume core) is consistent with geochemical evidence that these two forms of volcanism have distinct source materials (Yang et al, 2003;Hanyu et al, 2005;Fekiacova et al, 2007;Dixon et al, 2008).…”

Inherited Pb isotopic records in olivine antecryst-hosted melt inclusions from Hawaiian lavas

“…These trends are consistent with the previously identified temporal isotopic trend modeled by Tanaka et al (2002), which showed that the 207 Pb/ 206 Pb and 208 Pb/ 206 Pb of the Koolau magma systematically increased with time. In particular, the Pb isotope systematics of Type B inclusions in the Nuuanu 3 sample indicate that the earlier stage of Koolau magma generation was dominated by a 207 Pb/ 206 Pb and/or 208 Pb/ 206 Pb depleted component than what was expected from the bulk Pb isotopic composition (Tanaka et al, 2002;Fekiacova et al, 2007).…”

“…Two magmatic stages have been recognized during the formation of the Koolau shield: the older to younger main shield stage and the Makapuu stage (Shinozaki et al, 2002;Tanaka et al, 2002;Haskins and Garcia, 2004;Huang and Frey, 2005;Fekiacova et al, 2007). Sample D6-1 collected from Nuuanu 3 landside deposit has been suggested to be the oldest of the studied samples (Tanaka et al, 2002).…”

“…Kilauea and Mauna Kea) is dominated in peridotitic material intrinsic to the Hawaiian plume and that the involvement of a mafic component in the source could produce small-scale isotopic heterogeneity (e.g. Lassiter and Hauri, 1998;Kogiso et al, 2004 Stille et al, 1986;Lassiter and Hauri, 1998;Eisele et al, 2003;Fekiacova et al, 2007;Tanaka et al, 2008). Although the correlation between TiO 2 /Na 2 O and 207 Pb/ 206 Pb is less significant, TiO 2 /Na 2 O also suggests that many of the melt inclusions in Kilauea antecrysts show more Loa-type (i.e.…”

Probing the Earth’s Deep Interior Through Geochemistry

“…While this model can, perhaps, explain Sr and Nd isotopic systematics, it fails to explain combined Pb, Sr, and Nd systematics (and hence also correlated Hf isotopes), both in Hawaii (Roden et al, 1984) and elsewhere (White, 2010). An alternative proposed by White and Duncan (1996) for the Society Islands and Fekiacova et al (2007) for Hawaii is that rejuvenescent magmas are generated by melting of the sheath of more depleted material entrained by the plume as it rises through the deep mantle. In the Bianco et al (2005) model, the plume consists of a mixture of pods and lenses of pyroxenite and/or incompatible element-enriched peridotite distributed more or less uniformly in a matrix of depleted peridotite, the latter with a higher solidus temperature than the two former.…”