It seems possible that a sinking current of cooled mantle material on the upper side of the plate might be the cause of such deep basins.
看来，板块上侧冷却的地幔物质的下沉流可能是造成这种深盆地的原因。
2
Because of its proximity to Earth's core, the rock at the base of the mantle is much hotter than rock in the uppermantle.
由于靠近地核，地幔底部的岩石比上地幔岩石的温度高得多。
3
When a reservoir is sufficiently large, a sphere of this hot rock forces its way up through the uppermantle to Earth's surface, creating a broad bulge in the topography.