Magmatism is an important component of collision zones, and can occur for 10s of millions of years after initial plate collision, but during continued plate convergence. Hence the magmatism is closely related to the tectonic processes that occur in the colliding lithospheric plates and underlying asthenosphere. This session therefore solicits contributions from all disciplines which have a bearing on the origins and composition of the magmatic rocks, certainly petrology and geochemistry, but also structural geology and geophysics.