Eiler, John M. and Valley, John W. and Stolper, Edward M. (1996) Oxygen isotope ratios in olivine from the Hawaii Scientific Drilling Project. Journal of Geophysical Research B, 101 (B5). 11,807-11,813. ISSN 0148-0227 http://resolver.caltech.edu/CaltechAUTHORS:20120824-074858864
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Oxygen isotope ratios of olivine in 23 tholeiites from the Hawaii Scientific Drilling Project (HSDP) core (15 from Mauna Kea, 8 from Mauna Loa) and three samples of outcropping subaerial or dredged submarine Mauna Kea lavas have been measured by laser fluorination. The δ^(18)O values are 4.6–5.4 ‰, confirming previous observations that some Hawaiian lavas are derived from sources with δ^(18)O values lower than typical upper mantle (δ^(18)Oolivine ≈ 5.2±0.2 ‰). The Mauna Kea-Mauna Loa transition marks a shift from δ^(18)O values lower than the mantle average in Mauna Kea olivines (∼4.8) to more typical mantle values in Mauna Loa olivines. Lavas containing olivines with δ^(18)O values similar to the typical upper mantle are associated with more “primitive” or less depleted radiogenic isotope characteristics; i.e., with higher ^3He/^4He (>13 Ra), higher ^(87)Sr/^(86)Sr (>0.7036) and lower є_(Nd) (<6.5), and with ^(206)Pb/^(204)Pb ratios less than -18.3. These relationships indicate that the δ^(18)O values of the relatively enriched source components of the Hawaiian plume sampled by Mauna Loa lavas are comparable to (or greater than) the mantle average. This conclusion is supported by δ^(18)O values of olivine from other high ^3He/^4He islands, which are also comparable to the upper mantle average. The low δ^(18)O values in Hawaiian lavas are derived from a source having more MORB-like, or depleted, He, Nd, and Sr isotope ratios, but more radiogenic Pb than is seen in the Mauna Loa lavas Assimilation of ^(18)O-depleted lower oceanic crust from the underlying Pacific crust by hot, MgO-rich parental magmas or melting of older, recycled oceanic crust entrained in the Hawaiian plume are both possible sources of this ^(18)O-depleted, MORB-like component in Hawaiian magmas.
|Additional Information:||© 1996 American Geophysical Union. Received 15 May 1995; accepted 11 October 1995; published 10 May 1996. We gratefully acknowledge helpful reviews of this manuscript by Don DePaolo, Bruce Nelson, Mark Conrad, Ken Farley, Mike Garcia, Nuni-Lyn Anders, and Peter Reiners. We also thank Mike Garcia for providing additional samples of Mauna Kea analyzed for comparison with the samples from the HSDP core; Mike Baker, Erik Hauri, AI Hofmann, Mark Kurz, John Lassiter, and Mike Rhodes for providing isotopic and compositional data on samples from the HSDP core prior to their publication in this special section; and Mike Spicuzza and Narni Kitchen for assistance in the stable isotope laboratory at the University of Wisconsin. This work was supported in part by NSF grant EAR-91175SS supporting the HSDP project and grants from DOE (93ER143S9 to J.W.V., DEFG03-S5ERI3445 to E.M.S.) and NSF (93-04372 to J.W.V., EAR 93-03975 to E.M.S.). Caltech Division of Geological and Planetary Sciences contribution 5541.|
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|Official Citation:||Eiler, J. M., J. W. Valley, and E. M. Stolper (1996), Oxygen isotope ratios in olivine from the Hawaii Scientific Drilling Project, J. Geophys. Res., 101(B5), 11,807–11,813, doi:10.1029/95JB03194.|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Ruth Sustaita|
|Deposited On:||24 Aug 2012 15:32|
|Last Modified:||26 Dec 2012 16:02|
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