The effects of plate interface rheology on subduction kinematics and dynamics

SUMMARY Tectonic plate motions predominantly result from a balance between the potential energy change of subducting slab and viscous dissipation in mantle, bending lithosphere slab–upper interface. A wide range observations active subduction zones exhumed rocks suggest that interface shear zone rheology is sensitive to composition crustal material—for example, sediments versus mafic igneous oceanic crust. Here we use 2-D numerical models dynamically consistent systematically investigate how viscosity influences large-scale kinematics dynamics. Our model consists an beneath overriding continental plate. The includes crustal/weak layer controls We implement strengths explore respond for initial upper mantle stage, subsequent quasi-steady-state ponding near jump at 660-km-discontinuity. If material properties are suitably averaged, our results confirm effect strength on as based simplified analysis: ∼2 order magnitude increase can decrease convergence speeds by ∼1 magnitude. However, full dynamic solutions show interesting behaviour including interplay topography end-member weak interface-weak case break-off/tearing. Additionally, with spatially limited, sediment strip embedded regular material, might be expected different types materials through Earth’s history, transient response enhanced rollback velocity strong slabs. work substantiates earlier suggestions importance interface, expands quantifiable links reorganizations, nature incoming geological record.