Geochemical variations in the Cocos Plate subducting beneath Central America : implications for the composition of arc volcanism and the extent of the Galápagos Hotspot influence on the Cocos oceanic crust

Sadofsky, Seth, Hoernle, Kaj, Duggen, Svend, Hauff, Folkmar, Werner, Reinhard and Garbe-Schönberg, C.-Dieter (2009) Geochemical variations in the Cocos Plate subducting beneath Central America : implications for the composition of arc volcanism and the extent of the Galápagos Hotspot influence on the Cocos oceanic crust International Journal of Earth Sciences, 98 (4). pp. 901-913. DOI 10.1007/s00531-007-0289-5.

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Abstract

New geochemical data from the Cocos Plate constrain the composition of the input into the Central American subduction zone and demonstrate the extent of influence of the Galapagos Hotspot on the Cocos Plate. Samples include sediments and basalts from Ocean Drilling Program (ODP) Site 1256 outboard of Nicaragua, gabbroic sills from ODP Sites 1039 and 1040, tholeiitic glasses from the Fisher Ridge off northwest Costa Rica, and basalts from the Galapagos Hotspot Track outboard of Central Costa Rica. Site 1256 basalts range from normal to enriched MORB in incompatible elements and have Pb and Nd isotopic compositions within the East Pacific Rise MORB field. The sediments have similar Pb-206/Pb-204 and only slightly more radiogenic Pb-207/Pb-204 and Pb-208/Pb-204 isotope ratios than the basalts. Altered samples from the subducting Galapagos Hotspot Track have similar Nd and Pb isotopic compositions to fresh Galapagos samples but have significantly higher Sr isotopic composition, indicating that the subduction input will have a distinct geochemical signature from Galapagos-type mantle material that may be present in the wedge beneath Costa Rica. Gabbroic sills from Sites 1039 and 1040 in East Pacific Rise (EPR) crust show evidence for influence of the Galapagos Hotspot similar to 100 km beyond the morphological hotspot track

Document Type: Article
Keywords: central american subduction zonearc volcanism galapagos hotspot track plume-ridge interaction morb odp sites 1256, 1039, 1040 east pacific rise midocean ridge basalt costa-rica isotope geochemistry mantle sr nd asthenosphere existence evolution
Research affiliation: OceanRep > SFB 574 > C2
Kiel University
OceanRep > SFB 574
OceanRep > The Future Ocean - Cluster of Excellence
OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-MUHS Magmatic and Hydrothermal Systems
Refereed: Yes
DOI etc.: 10.1007/s00531-007-0289-5
ISSN: 1437-3254
Projects: Future Ocean
Contribution Number:
ProjectNumber
SFB 57494
Expeditions/Models:
Date Deposited: 16 Jul 2009 12:51
Last Modified: 23 Aug 2017 07:39
URI: http://eprints.uni-kiel.de/id/eprint/3811

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