Fluid escape from subduction zones controlled by channel-forming reactive porosity

摘要: Water within the oceanic lithosphere is returned to Earth’s surface at subduction zones. Observations of metamorphosed veins preserved in exhumed slabs suggest that fluid can escape via channel networks. Yet, it unclear how such channels form allow chemically bound water subducting slab as high pressures during reduce porosity rocks nearly zero. Here we use multiscale rock analysis combined with thermodynamic modelling show flow initiation dehydrating serpentinites controlled by intrinsic chemical heterogeneities, localizing dehydration reactions specific microsites. Porosity generation directly linked and resultant pressure variations force reactive release organize into vein networks across a wide range spatial scales (μm m). This channelization results large-scale sufficient fluxes drain plates. Moreover, our findings antigorite do not cause instantaneous embrittlement, often presumed trigger intermediate-depth zone seismicity. Pressure thought restrict from slab. Thermodynamic shows networks, which grow around local help plate.