Arc-parallel flow in the mantle wedge beneath Costa Rica and Nicaragua.

Hoernle, Kaj , Abt, D. L., Fischer, K. M., Nichols, H., Hauff, Folkmar , Abers, G. A., van den Bogaard, Paul, Heydolph, Ken, Alvarado, G., Protti, M. and Strauch, W. (2008) Arc-parallel flow in the mantle wedge beneath Costa Rica and Nicaragua. Nature, 451 (7182). pp. 1094-1097. DOI 10.1038/nature06550.

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Abstract

Resolving flow geometry in the mantle wedge is central to understanding the thermal and chemical structure of subduction zones, subducting plate dehydration, and melting that leads to arc volcanism, which can threaten large populations and alter climate through gas and particle emission. Here we show that isotope geochemistry and seismic velocity anisotropy provide strong evidence for trench-parallel flow in the mantle wedge beneath Costa Rica and Nicaragua. This finding contradicts classical models, which predict trench-normal flow owing to the overlying wedge mantle being dragged downwards by the subducting plate. The isotopic signature of central Costa Rican volcanic rocks is not consistent with its derivation from the mantle wedge1, 2, 3 or eroded fore-arc complexes4 but instead from seamounts of the Galapagos hotspot track on the subducting Cocos plate. This isotopic signature decreases continuously from central Costa Rica to northwestern Nicaragua. As the age of the isotopic signature beneath Costa Rica can be constrained and its transport distance is known, minimum northwestward flow rates can be estimated (63–190 mm yr-1) and are comparable to the magnitude of subducting Cocos plate motion (approx85 mm yr-1). Trench-parallel flow needs to be taken into account in models evaluating thermal and chemical structure and melt generation in subduction zones.

Document Type: Article
Research affiliation: OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-MUHS Magmatic and Hydrothermal Systems
OceanRep > SFB 574 > C2
OceanRep > SFB 574
Kiel University
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1038/nature06550
ISSN: 0028-0836
Related URLs:
Projects: MARGINS, SFB574, Future Ocean
Contribution Number:
ProjectNumber
SFB 574119
Expeditions/Models/Experiments:
Date Deposited: 03 Dec 2008 16:52
Last Modified: 23 Sep 2019 18:45
URI: http://oceanrep.geomar.de/id/eprint/2629

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