Insights from trace element geochemistry as to the roles of subduction zone geometry and subduction input on the chemistry of arc magmas.

Wehrmann, Heidi, Hoernle, Kaj , Garbe-Schönberg, Dieter, Jacques, Guillaume, Mahlke, Julia and Schumann, Kai (2014) Insights from trace element geochemistry as to the roles of subduction zone geometry and subduction input on the chemistry of arc magmas. International Journal of Earth Sciences, 103 (7). pp. 1929-1944. DOI 10.1007/s00531-013-0917-1.

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Abstract

Subduction zones of continental, transitional, and oceanic settings, relative to the nature of the overriding plate, are compared in terms of trace element compositions of mafic to intermediate arc rocks, in order to evaluate the relationship between subduction parameters and the presence of subduction fluids. The continental Chilean Southern Volcanic Zone (SVZ) and the transitional to oceanic Central American Volcanic Arc (CAVA) show increasing degrees of melting with increasing involvement of slab fluids, as is typical for hydrous flux melting beneath arc volcanoes. At the SVZ, the central segment with the thinnest continental crust/lithosphere erupted the highest-degree melts from the most depleted sources, similar to the oceanic-like Nicaraguan segment of the CAVA. The northern part of the SVZ, located on the thickest continental crust/lithosphere, exhibits features more similar to Costa Rica situated on the Caribbean Large Igneous Province, with lower degrees of melting from more enriched source materials. The composition of the slab fluids is characteristic for each arc system, with a particularly pronounced enrichment in Pb at the SVZ and in Ba at the CAVA. A direct compositional relationship between the arc rocks and the corresponding marine sediments that are subducted at the trenches clearly shows that the compositional signature of the lavas erupted in the different arcs carries an inherited signal from the subducted sediments.

Document Type: Article
Additional Information: WOS:000343216700013
Keywords: Subduction Zones; trace element geochemistry; hydrous flux melting; marine sediment input; Chilean Southern Volcanic Zone; Central American Volcanic Arc, Izu-Bonin-Marianas Arc
Research affiliation: OceanRep > The Future Ocean - Cluster of Excellence
OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-MUHS
OceanRep > SFB 574 > C2
OceanRep > SFB 574
OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-GDY Marine Geodynamics
Kiel University
Refereed: Yes
Open Access Journal?: No
Publisher: Springer
Projects: Future Ocean, SFB574
Contribution Number:
Project
Number
SFB 574
254
Expeditions/Models/Experiments:
Date Deposited: 26 Jul 2012 07:25
Last Modified: 23 Sep 2019 17:34
URI: https://oceanrep.geomar.de/id/eprint/14826

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