Mantle Plume, Planetary

Synonyms

Hotspot

Definition

Mantle plumes are columns of hot buoyant mantle that originate from a thermal boundary layer deep in the Earth. The most likely source of plumes is the core-mantle boundary at a depth of 2,900 km, although it has been suggested that small plumes may originate from the boundary between the upper and lower mantle at 670 km depth.

History

The Canadian geologist Tuzo Wilson suggested in 1963 that the age progression in the Hawaiian Islands was due to the oceanic lithosphere moving over a stationary “hot spot” in the mantle. Seven years later, the US geophysicist Jason Morgan recognized that Wilson’s hot spots were plumes of hot mantle that originated from the thermal boundary layer above the core.

Overview

Plumes must originate from thermal boundary layers, which in the case of Earth’s mantle is the core-mantle boundary or perhaps the boundary between lower and upper mantle. The core is hotter than the overlying mantle and it cools by conduction to the mantle,...