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Published November 1996 | public
Journal Article

Oxygen isotope constraints on the sources of Hawaiian volcanism


We have measured oxygen isotope ratios in 99 separates of olivine and 14 separates of plagioclase or glass from Hawaiian lavas. These data confirm that the source(s) of some Hawaiian basalts are lower in δ^(18)O than peridotite xenoliths and the source region for mid-ocean ridge basalts (MORB). Our data document correlations between oxygen and radiogenic isotope ratios and consistent differences in δ^(18)O between volcanoes. Low values of δ^(18)O are associated with a 'depleted' component that is relatively high in ^(206)Pb/^(204)Pb, low in ^3He/^4He, and anomalously low in ^(207)Pb/^(204)Pb relative to ^(206)Pb/^(204)Pb. This component is preferentially sampled in lavas from the so-called Kea trend volcanoes (Kilauea, Mauna Kea, Kohala and Haleakala). Low δ^(18)O values in the 'Kea' component suggest that it is hydrothermally altered oceanic crust. The similarity of the Kea end member to Pacific MORB in terms of Sr, Nd, and Pb isotope ratios further suggests that this component is assimilated from the local Pacific plate in subcrustal magma chambers. Anomalous ^(206)Pb/^(204)Pb-^(207)Pb/^(204)Pb relationships indicate recent enrichment in U/Pb in this component and further support the hypothesis that this component is young ( < 10^8 yr) Pacific crust. The isotopic distinctions between Loa and Kea trend volcanoes implies a systematic difference in the magma supply and plumbing systems of volcanoes on these two trends. Samples from Lanai and Koolau have 'enriched' radiogenic isotope compositions (radiogenic Sr and non-radiogenic Nd and Pb) and higher δ^(18)O than typical upper mantle values, suggesting the incorporation of recycled sediment and/or oceanic crust in their sources. Other isotopic end members to Hawaiian lavas (e.g., high ^3He/^4He and post-erosional lavas) have δ^(18)O values within the range typical of the upper mantle.

Additional Information

© 1996 Elsevier Science B.V. Received 16 February 1996. Revised 5 September 1996. Accepted 7 September 1996. Available online 26 February 1999. We thank Dave Clague, Fred Frey, Mike Garcia, and Don Thomas for graciously supplying samples for this study, John Lassiter, Mark Kurz, Erik Hauri and Mike Rhodes for sharing data prior to their publication, Mike Spicuzza and Nami Kitchen for assistance in the stable isotope laboratory at the University of Wisconsin, and Fred Frey, Emi Ito and Colin MacPherson for thorough reviews of this manuscript. This work was funded by NSF-9303975 and -9 I 17588 to EMS and 93-04372 to JWV, and DOE grants DEFG03-85ERl3445 to EMS and 93ERl4389 to JWV.

Additional details

August 22, 2023
October 18, 2023