Fluid Release from Subducted Slabs Without Percolation Flow – GWC Mag

Editors’ Highlights are summaries of recent papers by AGU’s journal editors.

Source: Journal of Geophysical Research: Solid Earth

What is a plausible alternative mechanism to the percolation flow of a water bearing fluid released out of a subducting slab? Chen et al. [2023] explore the possibility of stacking the released water in the effective 2D fluidic phase within intercalated crystalline interfaces of phyllosilicate minerals like graphite, mica, or brucite. Using molecular dynamic simulations, they demonstrate a possible conduit of water flow through an effective quasi-2D fluidic phase.

The authors find that, indeed, the water intercalation under pressure-temperature-conditions of subducting slabs is thermodynamically driven in the considered three kinds of crystalline interfaces: graphite, brucite, and muscovite mica interlayers. The indispensable condition for this water intercalation into the crystalline interface is that the crystalline surface and water should not be well connected by hydrogen bonds. The most important issue is that H₂O intercalation into the crystalline interface might facilitate aseismic slip, which may transmit easily earthquake-triggering stress changes making the dehydration embrittlement hypothesis less necessary.

Citation: Chen, M., Zhu, R., Zhu, J., & He, H. (2023). Percolation of low-dimensional water at crystalline interfaces mediates fluid migration in subducting slabs. Journal of Geophysical Research: Solid Earth, 128, e2023JB027124. https://doi.org/10.1029/2023JB027124

—Nikolai Bagdassarov, Associate Editor, JGR: Solid Earth

Text © 2023. The authors. CC BY-NC-ND 3.0
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