Mantle Plumes

A mantle plume is a proposed mechanism of convection within the Earth's mantle, hypothesized to explain anomalous volcanism. Because the plume head partially melts upon reaching shallow depths, a plume is often invoked as the cause of volcanic hotspots such as Hawaii or Iceland, and large igneous provinces such as the Deccan Traps and Siberian Traps.

History of the Concept

The idea of mantle plumes was first proposed by J. Tuzo Wilson in 1963 and was further developed by W. Jason Morgan in 1971 and 1972. According to the mantle plume hypothesis, super-heated material forms at the core-mantle boundary and rises through the Earth's mantle.

Structure and Dynamics

A mantle plume is posited to exist where super-heated material forms (nucleates) at the core-mantle boundary and rises through the Earth's mantle. Rather than a continuous stream, plumes should be viewed as a series of hot bubbles of material. Reaching the brittle upper Earth's crust, they form diapirs, which are dome-shaped intrusions of molten rock.

Volcanic Hotspots

Mantle plumes are often associated with volcanic hotspots. These are volcanic locales thought to be fed by underlying mantle that is anomalously hot compared with the surrounding mantle. Some notable examples of such hotspots include:

• Hawaii Hotspot: Responsible for the creation of the Hawaiian Islands.
• Yellowstone Hotspot: Known for its supervolcanic eruptions and geothermal activity.
• Iceland Hotspot: Partly responsible for the high volcanic activity that has formed the Iceland Plateau.

Large Igneous Provinces

Mantle plumes are also thought to be responsible for the formation of large igneous provinces (LIPs). These are extensive regions of volcanic rock, formed by massive volcanic eruptions. Examples of LIPs include:

• Deccan Traps: Located in India, formed around 66 million years ago.
• Siberian Traps: Located in Russia, formed around 252 million years ago.

Intraplate Volcanism

Intraplate volcanism refers to volcanic activity that occurs within a tectonic plate, as opposed to at the boundaries of tectonic plates. Mantle plumes have been invoked to explain this type of volcanism. This phenomenon is observed in locations like the Hawaiian Islands, which are situated far from the edges of the Pacific Plate.

Mantle Convection and Plumes

Mantle convection is the slow, churning motion of Earth's mantle caused by the heat from the core. Mantle plumes are thought to be an integral part of this process. They act as conduits for the transfer of heat and material from deep within the Earth to the surface.

Related Topics

• Earth's Mantle
• Volcanic Hotspots
• Core-Mantle Boundary
• Large Igneous Provinces

Understanding mantle plumes is crucial for comprehending the geological processes that shape our planet, from the formation of volcanic islands to the creation of large igneous provinces.