TY  - JOUR
A1  - Konrad-Schmolke, Matthias
A1  - Halama, Ralf
A1  - Manea, Vlad C.
T1  - Slab mantle dehydrates beneath KamchatkaYet recycles water into the deep mantle
JF  - Geochemistry, geophysics, geosystems
N2  - 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.
KW  - rainfall-runoff
KW  - scaling
KW  - heterogeneity in soil hydraulic properties
KW  - surface sealing
KW  - run-on
KW  - patched vegetation cover
Y1  - 2016
U6  - https://doi.org/10.1002/2016GC006335
SN  - 1525-2027
VL  - 17
SP  - 2987
EP  - 3007
PB  - American Geophysical Union
CY  - Washington
ER  -