The Chilean convergent margin south of the strait of Magellan represents an excellent opportunity to study a style of subduction where most of the parameters controlling this process remain approximately constant except one: obliquity. Modelling of Free Air anomaly data constrained with seismic data along a track perpendicular to the margin shows a well developed bathymetric terrace (Fuegian terrace) with a pronounced negative gravity anomaly, a common feature of active trenches, and a gently dipping (8U) slab subducting beneath the Scotia plate