Abstract

Slab windows have clear consequences for surface observations that are the manifestations of asthenospheric upwelling and uppermost mantle temperature anomalies. In this contribution we link geophysical and geochemical observations from modern slab windows to the asthenospheric flow, temperature field and extent of melting using different geometries. We use an analytical solution for the slab window geometry and implement this solution in 3D steady-state thermomechanical models to calculate the temperature and velocity field. Our results show that upwelling (>1 cm/yr) and temperature anomalies (>1400 C-degrees) are controlled by the ratio between the half-spreading rate and velocity of the overriding plate. The extent of melting depends on both the ratio of these velocities and ridge obliquity while flow patterns are controlled only by ridge obliquity. Finally, we construct ternary diagrams to estimate the efficiency of matrix/melt upwelling and maximum mean mantle temperatures based on plate kinematics and ridge obliquity. This novel approach was used to investigate the slab windows in Antarctica, South America and western North America.