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Göteborgs universitets publikationer

Slab mantle dehydrates beneath Kamchatka: yet recycles water into the deep mantle.

Författare och institution:
Matthias Konrad-Schmolke (Institutionen för geovetenskaper); Ralf Halama (-); Vlad Manea (-)
Publicerad i:
Geochemistry Geophysics Geosystems, Epub ahead of print
ISSN:
1525-2027
Publikationstyp:
Artikel, refereegranskad vetenskaplig
Publiceringsår:
2016
Språk:
engelska
Fulltextlänk:
Sammanfattning (abstract):
The subduction of hydrated slab mantle is the most important and yet weakly constrained factor in the quantification of the Earth's deep geologic water cycle. The most critical unknowns are the initial hydration state and the dehydration behavior of the subducted oceanic mantle. Here we present a combined thermomechanical, thermodynamic, and geochemical model of the Kamchatka subduction zone that indicates significant dehydration of subducted slab mantle beneath Kamchatka. Evidence for the subduction of hydrated oceanic mantle comes from across-arc trends of boron concentrations and isotopic compositions in arc volcanic rocks. Our thermodynamic-geochemical models successfully predict the complex geochemical patterns and the spatial distribution of arc volcanoes in Kamchatka assuming the subduction of hydrated oceanic mantle. Our results show that water content and dehydration behavior of the slab mantle beneath Kamchatka can be directly linked to compositional features in arc volcanic rocks. Depending on hydration depth of the slab mantle, our models yield water recycling rates between 1.1 × 103 and 7.4 × 103 Tg/Ma/km corresponding to values between 0.75 × 106 and 5.2 × 106 Tg/Ma for the entire Kamchatkan subduction zone. These values are up to one order of magnitude lower than previous estimates for Kamchatka, but clearly show that subducted hydrated slab mantle significantly contributes to the water budget in the Kamchatkan subduction zone.
Ämne (baseras på Högskoleverkets indelning av forskningsämnen):
NATURVETENSKAP ->
Geovetenskap och miljövetenskap
NATURVETENSKAP ->
Geovetenskap och miljövetenskap ->
Geokemi
Nyckelord:
rainfall-runoff;scaling;heterogeneity in soil hydraulic properties;surface sealing;run-on;patched vegetation cover
Postens nummer:
239931
Posten skapad:
2016-08-08 11:55
Posten ändrad:
2016-08-19 09:16

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