NUMERICAL MODEL OF EARLY CONTINENT FORMATION

The mantle’s water content and temperature are both highly influential and poorly constrained factors that affect the time of formation of early continents, their persistence at the surface, and their rate of accretion. One challenge in understanding the effect of these factors is their competing influences. Water content can increase erosion by decreasing viscosity, while also increasing crustal production by lowering melting points. High temperatures lowers rock viscosity while also decreasing water content, making its ultimate effect unclear. I am constructing a simple box model that seeks to understand how varying these factors, along with silica content, changes the time and speed of continental formation and the persistence of generated crust.

Material in the box evolves over time according to a fluid mechanical model, where we numerically solve equations of mass, momentum, and energy. Currently I am developing the model to keep numerical errors sufficiently small for accurate advection of compositional fields and the compounding error of interpolation and integration. Further developments of the model will include components that will allow temperature and chemical composition to dictate mantle melting and simulate the formation of continental crust. From there I will be able to study the model’s predictions of how water content, temperature, and silica content affect the formational time, persistence, and rate of accretion of early continents. I will analyze the model results in terms of available geological record in order to deduce the model’s limitations. I plan to present the known limitations as well as the model’s conclusions at the GSA convention.