Were There Moving 'Plumelets' in the South Brazilian Continental Lithosphere

It is proposed that melt fronts generated by Tristan da Cunha plume during Cretaceous times is the deep thermal process responsible for the observed features in the spatial distribution of heat flow anomalies and alkaline magmatism in southern Brazil. Model studies indicate that plume derived melts can move over large distances without losing much of their thermal energy. Changes in the flow rates of such plumelets along networks of deep lithospheric channels can account for the observed age pattern of alkaline intrusives. It is likely that melt fronts are currently located at or near areas of high heat flow and suitable geoelectrical sounding methods should be capable of detecting their presence.