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Boninites and adakites from the northern termination of the tonga trench: Implications for adakite petrogenesis


Falloon, TJ and Danyushevsky, LV and Crawford, AJ and Meffre, SJM and Woodhead, JD and Bloomer, Sh, Boninites and adakites from the northern termination of the tonga trench: Implications for adakite petrogenesis, Journal of Petrology, 49, (4) pp. 697-715. ISSN 0022-3530 (2008) [Refereed Article]

DOI: doi:10.1093/petrology/egm080


Adakitic rocks were recovered by dredging from the northern termination of the Tonga Trench during the 1984 voyage of the R.V. Natsushima and the 1996 voyage of the R.V. Melville. These contain magmatic zircons that have been dated at 2·5 Ma by U-Pb methods, indicating that they are contemporaneous with boninite magmatism previously described from this area. This is the first time adakites and high-Ca boninites have been reported from the same active tectonic setting. The Tonga adakites are classified as high-SiO2 adakites, and are compositionally consistent with an origin as partial melts of subducted Pacific oceanic crust and sediment. Geochemical modelling suggests that the adakites are not involved in the petrogenesis of the Tongan high-Ca boninites. However, the recovery of adakites and boninites from the termination of the northern Tonga Trench suggests that both magma types are related to the unique tectonic setting of this region, where a transition from steep subduction to a transform fault plate boundary has created a slab window with an associated slab edge. Boninites are generated as a result of hot Samoan plume mantle moving through the slab window and subsequently being fluxed by H2O-rich fluids from the subducting Pacific oceanic crust. The Tonga adakites, in contrast, result from the direct melting of the slab edge as a result of the juxtaposition of the subducting slab against hot mantle derived from the Samoan plume. © The Author 2008. Published by Oxford University Press. All rights reserved.

Item Details

Item Type:Refereed Article
Research Division:Earth Sciences
Research Group:Geology
Research Field:Igneous and metamorphic petrology
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the earth sciences
UTAS Author:Falloon, TJ (Dr Trevor Falloon)
UTAS Author:Danyushevsky, LV (Professor Leonid Danyushevsky)
UTAS Author:Crawford, AJ (Professor Anthony Crawford)
UTAS Author:Meffre, SJM (Dr Sebastien Meffre)
ID Code:56630
Year Published:2008
Web of Science® Times Cited:114
Deposited By:Centre for Ore Deposit Research - CODES CoE
Deposited On:2009-05-18
Last Modified:2009-05-21

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