Volatile Cycling and Planetary Evolution

The thermal history of terrestrial planets is investigated using a parameterized model that couples thermal convection and volatile cycling. The model breaks volatile inventory into surface and interior reservoirs and calculates the exchange between them. A volatile-dependent mantle rheology is incorporated. We focus on water at this stage. Water recycling into the mantle is assumed to occur principally through subduction of a hydrated serpentine layer whose thickness is self-determined based on serpentine stability. Degassing occurs through magmatism which is parameterized using a volatile dependent solidus. We present preliminary results that explore model parameter space. We have also coupled a radiative-convective climate model to our mantle-volatile model to explore the feedback effects between changing climate conditions, due to mantle degassing, and volatile cycling through the mantle. The model stress state is monitored for all parameter sweeps so as to evaluate the potential of changes in the tectonic mode of a planet (plate tectonics or a single plate mode).