Are the regional variations in Central American arc lavas due to differing basaltic versus peridotitic slab sources of fluids?.

Rüpke, Lars H., Phipps Morgan, Jason, Hort, Matthias and Connolly, James A. D. (2002) Are the regional variations in Central American arc lavas due to differing basaltic versus peridotitic slab sources of fluids?. Geology, 30 (11). pp. 1035-1038. DOI 10.1130/0091-7613(2002)030<1035:ATRVIC>2.0.CO;2.

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Abstract

Central American arc volcanism shows strong regional trends in lava chemistry that result from differing slab contributions to arc melting. However, the mechanism that transfers slab-derived trace elements into the mantle wedge remains largely unknown. By using a dynamic model for mantle flow and fluid release, we model the fate of three different slab-fluid sources: sediment, ocean crust, and serpentinized mantle. In the open subarc system, sediments lose almost all their highly fluid mobile elements by ∼50 km depth, so other fluid sources are necessary to explain the slab signal in arc-lava compositions. The well-documented transition from lavas with a strong geochemical slab signature (i.e., high Ba/La ratios) found in Nicaragua to lavas with a weaker slab signature (i.e., low Ba/La ratios) erupted in Costa Rica seems easiest to produce by a higher fraction of serpentine-hosted fluids released from the deeply faulted, highly serpentinized lithosphere subducting beneath Nicaragua than from the less deeply faulted, thicker, amphibolitic oceanic-crust and oceanic-plateau lithosphere subducting beneath Costa Rica.

Document Type: Article
Keywords: Central America, serpentinization, subduction zone, geochemistry, fluid release, modeling
Research affiliation: OceanRep > SFB 574 > C5
OceanRep > SFB 574
OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-GDY Marine Geodynamics
OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-MUHS Magmatic and Hydrothermal Systems
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1130/0091-7613(2002)030<1035:ATRVIC>2.0.CO;2
ISSN: 0091-7613
Projects: SFB574
Contribution Number:
ProjectNumber
SFB 57422
Date Deposited: 07 Apr 2010 11:50
Last Modified: 26 Sep 2017 08:18
URI: http://oceanrep.geomar.de/id/eprint/7692

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