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A hotspot's position on the Earth's surface is independent of tectonic plate boundaries, and so hotspots may create a chain of volcanoes as the plates move above them. There are two hypotheses that attempt to explain their origins. One suggests that hotspots are due to mantle plumes that rise as thermal diapirs from the core–mantle boundary. [2]
In 1977 researchers M. Kumazawa and Y. Fukao [1] introduced the term "mesoplate" in the context of what they termed a "Dual Plate Tectonic Model." Their rationale is a postulated low-velocity zone near and above the 650 km discontinuity with additional properties including local low melting temperature, active chemical migration and fractionation, and low-viscosity.
John Tuzo Wilson (October 24, 1908 – April 15, 1993) was a Canadian geophysicist and geologist who achieved worldwide acclaim for his contributions to the theory of plate tectonics. He added the concept of hot spots , a volcanic region hotter than the surrounding mantle (as in the Hawaii hotspot ).
In plate tectonics, the outermost part of the Earth known as the lithosphere (the crust and uppermost mantle) act as a single mechanical layer. The lithosphere is divided into separate "plates" that move relative to each other on the underlying, relatively weak asthenosphere in a process ultimately driven by the continuous loss of heat from the ...
Plate tectonics (from Latin tectonicus, from Ancient Greek τεκτονικός (tektonikós) 'pertaining to building') is the scientific theory that Earth's lithosphere comprises a number of large tectonic plates, which have been slowly moving since 3–4 billion years ago.
The plate theory is a model of volcanism that attributes all volcanic activity on Earth, even that which appears superficially to be anomalous, to the operation of plate tectonics. According to the plate theory, the principal cause of volcanism is extension of the lithosphere .
Tectonic plates generally focus deformation and volcanism at plate boundaries.However, the Hawaii hotspot is more than 3,200 kilometers (1,988 mi) from the nearest plate boundary; [1] while studying it in 1963, Canadian geophysicist J. Tuzo Wilson proposed the hotspot theory to explain these zones of volcanism so far from regular conditions, [3] a theory that has since come into wide acceptance.
Where hotspots are developed beneath the continents the products are different, as the mantle-derived magmas cause melting of the continental crust, forming granitic magmas that reach the surface as rhyolites. The Yellowstone hotspot is an example of continental hotspot magmatism, which also displays time-progressive shifts in magmatic activity.