Page "Mantle plume" Paragraph 14

The source of mantle plumes, is postulated to be the core-mantle boundary at 3, 000 km depth.

Because there is little material transport across the core-mantle boundary, heat transfer must occur by conduction, with adiabatic gradients above and below this boundary.

The core-mantle boundary is a strong thermal ( temperature ) discontinuity.

The temperature of the core is approximately 1, 000 degrees Celsius higher than that of the overlying mantle.

Plumes are postulated to rise as the base of the mantle becomes hotter and more buoyant.