The magmatic system beneath the Tristan da Cunha Island: Insights from thermobarometry, melting models and geophysics

Constraints on the depth and degree of melting at the source of Tristan basanites were derived from REE inverse modelling using our new trace element data. The model predicts 5% melt generation from a melting column with its base at 80-100 km and a top at 60 km, which is consistent with the lithospheric thickness resulting from cooling models and seismological observations. The thermobarometry and melting models combined suggest a mantle potential temperature of about 1360 °C for the Tristan hotspot.