Backarc Lithospheric Thickness and Serpentine Stability Control Slab‐Mantle Coupling Depths in Subduction Zones

A key feature of subduction zone geodynamics and thermal structure is the point at which slab mantle mechanically couple. This defines depth traction between begins to drive wedge circulation also corresponds with a rapid increase in temperature along slab-mantle interface. Here, we consider effects backarc parameter on coupling using two-dimensional thermomechanical models oceanic-continental convergent margins. Coupling strongly correlated lithospheric thickness, weakly parameter. Slab-mantle becomes significant where weak, hydrous antigorite reacts form strong, anhydrous olivine pyroxene Highly efficient (predominantly advective) heat transfer asthenospheric inefficient conductive) results competing feedbacks that stabilize antigorite-out reaction depths determined primarily by mechanical thickness lithosphere. For segments can be inverted from surface flow, our provide regression model applied predict depth. Consistently high flow circum-Pacific zones suggests uniformly thin overriding plates likely regulated erosion caused hydration melting processes under volcanic arcs. may explain common globally.