| Abstract: | The source of hotspot volcanism lies in metasomatized regions of the continental mantle proximal to ancient sutures and failed rifts. Such regions are prone to melting under hotcell conditions on continental rifting, and to erosion into the deeper mantle by asthenospheric flow. In opening basins, rifting parallel to such sutures or failed rifts delaminates and cycles continental mantle into the MORB source. Rifting at some angle to a suture or failed rift generates a hotspot track by preferential melting of the metasomatized mantle as it is cycled toward the rift axis. Continental mantle eroded into the asthenosphere becomes displaced from the continent by net westward drift of the lithosphere relative to the deep mantle to give rise to hotspot volcanism in long-lived ocean basins. |
