Seismo Lab Brown Bag Seminar

Venus' tectonic evolution is not well understood. Thousands of kilometers of possible subduction sites on Venus have been identified along networks of rift zone trenches called chasmata. Proposed subduction sites such as Artemis and Latona Corona have high elastic thicknesses and bending moments comparable to certain subduction zones on Earth. Yet, it is unclear how subduction at these locations would operate in the presence of a thick layer (~20-30 km) of positively buoyant basaltic crust. Here, we use 2D and 3D numerical models to show how regional-scale lithospheric recycling can be initiated at chasma rift zones. Rather than subduction, we observe a new tectonic regime called "peel-back delamination", where the negative thermal buoyancy of the lithospheric mantle causes it to decouple and peel away from a layer of highly-deformed, positively buoyant crust at the surface. In this talk, I will present the conditions required for delamination initiation and use these constraints to suggest the locations on Venus where peel-back delamination is most likely to operate.