Subduction cycling of volatiles and trace elements through the Central American volcanic arc: evidence from melt inclusions |
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| Authors: | Seth J Sadofsky Maxim Portnyagin Kaj Hoernle Paul van den Bogaard |
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| Institution: | (1) SFB 574, University of Kiel, Wischhofstr. 1-3, Kiel, 24148, Germany;(2) Leibniz Institute for Marine Sciences (IFM-GEOMAR), Wischhofstr. 1-3, Kiel, 24148, Germany;(3) Vernadsky Institute, Kosigin st. 19, 119991 Moscow, Russia |
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| Abstract: | Compositions of melt inclusions in olivine (Fo90-64) from 11 localities in Guatemala, Nicaragua and Cost Rica along the Central American Volcanic Arc are used to constrain combined
systematics of major and trace elements and volatile components (H2O, S, Cl, F) in parental melts and to estimate volcanic fluxes of volatile elements. The melt inclusions cover the entire
range of compositions reported for whole rocks from Central America. They point to large heterogeneity of magma sources on
local and regional scales, related to variable contributions of diverse crustal (from the subducting and overriding plates)
and mantle (from the wedge and incoming plate) components involved in magma genesis. Water in parental melts correlates inversely
with Ti, Y and Na and positively with Ba/La and B/La (with the exception of Irazú Volcano), which indicates mantle melting
fluxed by Ba-, B- and H2O-rich, possibly, serpentinite-derived fluid beneath most parts of the arc. Different components with melt-like characteristics
(high LREE, La/Nb and probably also Cl, S and F and low Ba/La) control the geochemical peculiarities of Guatemalan and Costa
Rican magmas. The composition of parental magmas together with published data on volcanic volumes and total SO2 flux from satellite measurements are used to constrain fluxes of volatile components and to estimate total magmatic flux
in Central America. We found that volcanic flux accounts for only 13% of total magmatic and volatile fluxes. The remaining
87% of magmas remained in the lithosphere to form cumulates (∼39%) and intrusives (∼48%). The intrusive fraction of magmatic
flux may be significantly larger beneath Nicaragua compared to Costa Rica. Interestingly, total fluxes of magmas and volatiles
in Central America are quite similar to the global average estimates.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. |
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