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Age and geochemistry of the oceanic Manihiki Plateau, SW Pacific: New evidence for a plume origin

Citation

Timm, C and Hoernle, K and Werner, R and Hauff, F and van den Bogaard, P and Michael, P and Coffin, MF and Koppers, A, Age and geochemistry of the oceanic Manihiki Plateau, SW Pacific: New evidence for a plume origin, Earth and Planetary Science Letters, 304, (1-2) pp. 135-146. ISSN 0012-821X (2011) [Refereed Article]


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Copyright Elsevier 2011 The definitive version is available at http://www.sciencedirect.com

DOI: doi:10.1016/j.epsl.2011.01.025

Abstract

We present 40Ar/39Ar age and geochemical (major and trace element and SrNdHfPb isotope) data from submarine samples recovered from the basement of the Manihiki Plateau during the R/V Sonne research expedition SO193. The samples, predominately tholeiites, with minor occurrences of basaltic andesites and hawaiites, give a mean age of 124.6 1.6 Ma from four different localities on the plateau. Based on TiO2 content, we define two groups of volcanic rocks that differ in trace element and isotopic compositions. Partial melting modeling suggests that the low-Ti group lavas were derived through large degrees of melting (c. 30%) of a peridotitic source at mantle potential melting temperatures of c. Tp = 1510 C, more than 100 C above the ambient mantle potential melting temperature. Since the primary water contents of both groups of lavas are low (0.10.3g wt.%) and the source is peridotitic, excess temperature is most likely the reason for the large degrees of melting producing the large volume of plateau basalts, consistent with the involvement of a mantle plume. The incompatible element contents of the low-Ti group lavas show a multistage history with enrichment in the most incompatible elements of a previously highly depleted source. They have isotopic compositions similar to enriched mid-ocean-ridge basalt (EMORB) and similar to the common focal zone (FOZO) component. The high-Ti group lavas have more enriched incompatible element compositions overall. Their isotopic compositions tend towards an enriched mantle (EMI)-type endmember, similar, although less extreme, than lavas from the Pitcairn Islands. The geochemistry of the Manihiki Plateau can best be explained by a plume containing three components: 1) a dominant peridotitic FOZO-type component, 2) delaminated EMI-type subcontinental lithospheric mantle (SCLM), and 3) a HIMU (recycled oceanic crustal)-type component possibly in the form of eclogite/pyroxenite. The similarity in age and geochemical composition of Manihiki, Hikurangi and Ontong Java basement lavas, including volcanism in some adjacent basins, suggests that the Greater Ontong Java Volcanic Event covered c. 1% of the Earth's surface with volcanism.

Item Details

Item Type:Refereed Article
Keywords:Oceanic large igneous province, Greater Ontong Java Event, lower mantle plume origin, secondary plumes, argon dating, geochronology, igneous geochemistry, isotopic composition, mantle plume, partial melting, submarine plateau, trace element, volcanic
Research Division:Earth Sciences
Research Group:Geology
Research Field:Marine Geoscience
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Earth Sciences
Author:Coffin, MF (Professor Mike Coffin)
ID Code:73757
Year Published:2011
Web of Science® Times Cited:26
Deposited By:IMAS Research and Education Centre
Deposited On:2011-10-25
Last Modified:2017-10-31
Downloads:3 View Download Statistics

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