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

Timm, Christian , Hoernle, Kaj , Werner, Reinhard, Hauff, Folkmar , van den Bogaard, Paul, Michael, Peter, Coffin, Millard and Koppers, Anthony (2011) 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. DOI 10.1016/j.epsl.2011.01.025. Date online first: 2010

[thumbnail of 2011_Timm_et_al_EPSL.pdf] Text
2011_Timm_et_al_EPSL.pdf - Published Version
Restricted to Registered users only

Download (1MB) | Contact

Supplementary data:

Abstract

We present 40Ar/39Ar age and geochemical (major and trace element and Sr–Nd–Hf–Pb 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 (0.1–0.3g 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.

Document Type: Article
Keywords: Meeresgeologie; Volcanology; Manihiki Plateau, oceanic large igneous province, 40Ar/39Ar age dates, major and trace element and Sr-Nd-Hf-Pb isotope geochemistry, volatiles, Greater Ontong Java Event
Research affiliation: OceanRep > The Future Ocean - Cluster of Excellence
OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-MUHS
Refereed: Yes
Open Access Journal?: No
Publisher: Elsevier
Related URLs:
Projects: Future Ocean
Expeditions/Models/Experiments:
Date Deposited: 24 Nov 2010 14:09
Last Modified: 26 Oct 2020 13:52
URI: https://oceanrep.geomar.de/id/eprint/10137

Actions (login required)

View Item View Item