A genetic link between silicic slab components and calc-alkaline arc volcanism in central Mexico

Straub, S. M., Zellmer, G. F., Gomez-Tuena, A., Espinasa-Perena, R., Martin-del Pozzo, A. L., Stuart, F. M. and Langmuir, C. H. (2014) A genetic link between silicic slab components and calc-alkaline arc volcanism in central Mexico. Geological Society, London, Special Publications, 385(1), pp. 31-64. (doi:10.1144/SP385.14)

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Abstract

A fundamental question in the formation of orogenic andesites is whether their high melt SiO2 reflects the recycling of silicic melts from the subducted slab or the processing of basaltic mantle melts in the overlying crust. The latter model is widely favoured, because most arc magmas lack the 'garnet' signature of partial slab melts. Here we present new trace element data from Holocene high-Mg# >64-72 calc-alkaline basalts to andesites (50-62 wt% SiO2) from the central Mexican Volcanic Belt that crystallize high-Ni olivines with the high 3He/4He = 7-8 of the upper mantle. These magmas have been proposed to be partial melts from 'reaction pyroxenites', which formed by hybridization of mantle peridotite (c. 82-85%) and heavy rare earth elementdepleted silicic slab melt (>15-18%). Forward and inverse models suggest that the absence of a garnet signature in these melts reflects the efficient buffering of the heavy rare earth elements (Ho to Lu) in the subarc mantle. In contrast, all elements more incompatible than H-excepting TiO2-are more or less strongly controlled by the silicic slab flux that also directly contributes to the silicic arc magma formation. Our study emphasizes the strong link between slab recycling and the genesis of orogenic andesites.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Stuart, Professor Finlay
Authors: Straub, S. M., Zellmer, G. F., Gomez-Tuena, A., Espinasa-Perena, R., Martin-del Pozzo, A. L., Stuart, F. M., and Langmuir, C. H.
College/School:College of Science and Engineering > Scottish Universities Environmental Research Centre
Journal Name:Geological Society, London, Special Publications
Publisher:Geological Society of London
ISSN:0305-8719
ISSN (Online):2041-4927

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