mantleplume

A mantle plume is a theoretical structure in geology and geophysics that describes a rising column of abnormally hot rock within the Earth's mantle. These plumes are thought to originate deep within the mantle, possibly near the core-mantle boundary, and ascend toward the surface due to their buoyancy. Mantle plumes are believed to play a significant role in plate tectonics and volcanic activity, particularly in the formation of hotspot volcanoes.

The concept of mantle plumes was first proposed in the 1970s by geophysicists to explain the existence of intraplate volcanic activity, such as the Hawaiian Islands and Iceland. Unlike most volcanic activity, which occurs at plate boundaries, hotspot volcanoes form far from tectonic plate edges. The plume theory suggests that these hotspots are fed by stationary plumes of magma rising from deep within the mantle, while the overlying lithospheric plate moves over them, creating chains of volcanoes.

Mantle plumes are characterized by their high temperatures, which can exceed those of the surrounding mantle by several hundred degrees Celsius. As they rise, they may partially melt due to decompression, generating magma that can erupt at the surface. The plume's interaction with the lithosphere can also cause uplift, forming broad regions of elevated terrain known as swells.

Evidence supporting the mantle plume hypothesis includes seismic tomography, which reveals anomalous structures beneath hotspots, and geochemical studies that show distinct isotopic signatures in hotspot lavas. However, the exact mechanisms driving plume formation and their dynamics remain topics of ongoing research. Alternative models, such as lithospheric-scale convection or crustal-scale processes, have also been proposed to explain certain volcanic phenomena.

While mantle plumes are widely accepted as a key geological process, their full complexity and variability continue to be studied through field observations, laboratory experiments, and computational modeling.