Ascending columns of superheated mantle originating at the core-mantle boundary.

• A. Mantle Plume
• B. Mantle Convection
• C. Plume Head
• D. Core Flow

Answer: (A)

This item tests how heat from deep inside the Earth moves upward through the mantle. Ascending columns of superheated mantle originating at the core–mantle boundary are mantle plumes. A mantle plume is a buoyant, hot rock that rises from near the core–mantle boundary toward the surface, forming a vertical column of upwelling material. As the plume continues upward, it may develop a broader plume head near the lithosphere that can cause surface volcanism, but the rising column itself is the core feature described here. This is distinct from mantle convection in general, which describes broader patterns of upwelling and downwelling in the mantle, and from core flow, which occurs in the outer core rather than in the mantle.