This program will develop three-dimensional numerical models of triple junctions to examine patterns of mantle flow and melting and crustal accretion. While important in the plate tectonic record, triple junctions have not been fully examined in terms of their impact on such processes as crustal accretion. The numerical models will take into account variable viscosity, melting, buoyancy, and migration of triple junctions in the absolute plate reference frame. Through the addition of a thermally buoyant melt source, the numerical models will also consider plume-ridge interaction and the formation of marine large igneous provinces. Broader impacts of the proposed work include contributing to the resolution of fundamental questions about triple junctions and large igneous provinces, training of a graduate student, and support for a new investigator.