The generation of continental flood basalts by decompression melting of internally heated mantle

Modeled primary magma compositions for flood basalts from the Central Atlantic magmatic province and the Ferrar large igneous province (Antarctica) require mantle potential temperatures (T (sub P) ) of 1450 + or - 50 degrees C, with melting taking place over a pressure range of approximately 2.0 GPa to <0.5 GPa. This range of T (sub P) is consistent with internal warming of mantle insulated by continental lithosphere, and does not necessarily require a mantle plume. The substantial crustal attenuation needed to allow decompression melting was facilitated by plate boundary forces that accompanied continental breakup. However, continental fragmentation and the plate boundary forces necessary to drive low-T (sub P) rift-related magmatism may still require the action of hot mantle plumes.