Go to  Advanced Search

East Molokai and other Kea-trend volcanoes: Magmatic processes and sources as they migrate away from the Hawaiian hot spot.

Show simple item record

dc.contributor.author Weis, Dominique
dc.date.accessioned 2011-11-16T22:49:07Z
dc.date.available 2011-11-16T22:49:07Z
dc.date.issued 2005
dc.identifier.citation Xu, Guangping; Frey, Frederick A.; Clague, David A.; Weis, Dominique; Beeson, Melvin H. (2005). East Molokai and other Kea-trend volcanoes: Magmatic processes and sources as they migrate away from the Hawaiian hot spot. Geochemistry, Geophysics, Geosystems, 6(5), Q05008, dx.doi.org/10.1029/2004GC000830. en_US
dc.identifier.uri http://hdl.handle.net/2429/39101
dc.description.abstract There are geochemical differences between shield lavas from the two parallel trends, Kea and Loa, defined by young Hawaiian volcanoes. The shield of East Molokai volcano, at greater than 1.5 Ma, is the oldest volcano on the Kea trend. Sequences of older tholeiitic to younger alkalic basalt that erupted as this volcano evolved from the shield to postshield stage of volcanism are well exposed. Much younger, ∼0.34–0.57 Ma, alkalic basalt and basanite erupted during rejuvenated stage volcanism. Like rejuvenated stage lavas erupted at other Hawaiian volcanoes, rejuvenated stage East Molokai lavas have relatively low 87Sr/86Sr and high 143Nd/144Nd. Such ratios reflect a source component with a long-term depletion in abundance of incompatible elements. On the basis of positive correlations of 87Sr/86Sr versus 206Pb/204Pb and negative correlations of these isotopic ratios with Nb/Zr, a smaller proportion of this depleted component also contributed to the late shield/postshield lavas erupted at East Molokai and the other Kea-trend volcanoes, Haleakala and Mauna Kea. At each of these Kea-trend volcanoes, as the volcano moved away from the hot spot, the extent of melting and magma supply from the mantle decreased, the depth of melt segregation increased, and there was an increasing role for a component with long-term relative depletion in incompatible elements. This depleted component has Kea-trend Pb isotopic characteristics and relatively low 208Pb/204Pb at a given 206Pb/204Pb, and it is probably not related to oceanic lithosphere or the source of mid-ocean ridge basalt. The overlap in Sr, Nd, and Pb isotope ratios of recent Kilauea shield lavas and 550 ka Mauna Kea shield lavas has been used to argue that Kea-trend shield volcanism samples a vertically continuous, geochemically distinct stripe which persisted in the hot spot source for 550 kyr (Eisele et al., 2003; Abouchami et al., 2005). As Kea-trend volcanoes migrate away from the hot spot and evolve from the shield to postshield stage, there are systematic changes in Sr, Nd, and Pb isotope ratios. However, the overlap of Sr, Nd, and Pb isotope ratios in late shield/postshield lavas from Mauna Kea (<350 ka) and East Molokai (∼1.5 Ma) show that the periphery of the hot spot sampled by Kea-trend postshield lavas also had long-term geochemical homogeneity. An edited version of this paper was published by AGU. Copyright 2005 American Geophysical Union. en_US
dc.language.iso eng en_US
dc.publisher American Geophysical Union en_US
dc.title East Molokai and other Kea-trend volcanoes: Magmatic processes and sources as they migrate away from the Hawaiian hot spot. en_US
dc.type text en_US
dc.type.text article en_US
dc.description.affiliation Earth and Ocean Sciences, Dept. of (EOS), Dept of en_US
dc.description.reviewstatus Reviewed en_US
dc.rights.copyright Weis, Dominique en_US
dc.description.scholarlevel Faculty en_US


Files in this item

Files Size Format Description   View
Weis_AGU_2004GC000830.pdf 2.303Mb Adobe Portable Document Format   View/Open
 

This item appears in the following Collection(s)

Show simple item record

All items in cIRcle are protected by copyright, with all rights reserved.

UBC Library
1961 East Mall
Vancouver, B.C.
Canada V6T 1Z1
Tel: 604-822-6375
Fax: 604-822-3893