This award supports a two year project to investigate the dynamics of the marginal zone of the Siple Coast ice streams using existing velocity and temperature profiles. The flow and stress fields will be modeled using finite element methods and a thermo-mechanical model will be used to investigate the coupling of the flow and temperature fields. Direct comparison of these models with the observed velocity profiles will lead to estimates of the structure of the margins and the softening of the marginal ice. The distribution of basal and marginal shear stress will be investigated, leading to an estimate of the relative roles of the bed and the margins in the overall force balance of the ice streams.