Melt generation at volcanic continental margins: no need for a mantle plume?

Melt generation in a rifting environment is studied using a dynamic 2-D fin ite element model. The lithosphere is extended to large, realistic thinning factors assuming a mantle temperature of 1333 degreesC. The focussing of d eformation results in a distribution of thinning factors along the margin a t breakup time consistent with observations. The timing of melt production (late synrift) and the amounts of melt are consistent with observations at volcanic margins. The dynamical. processes related to lithospheric rifting enhance the. produced melt volumes sufficiently to explain the sometimes en igmatic melt volumes found at volcanic margins.