The source of the Siberian Traps basalt was , probably , a mantle plume at the base of the crust which erupted through the Siberian craton ( the oldest part of the Siberian continental plate ) . The source of the Siberian Traps basalt has variously been attributed to a mantle plume which impacted the base of the crust and erupted through the Siberian Craton , or to processes related to plate tectonics .