(150 wORDS) 10 MARKS 2018 GENERAL STUDIES 1 UPSC CSE
A mantle plume is a large column of hot rock rising through the mantle. The heat from the plume causes rocks in the lower lithosphere to melt. The largest mantle plumes are presumed to form where a large volume of mantle rock is heated at the core-mantle boundary.
Most volcanos occur at plate boundaries, where two tectonic plates meet. But some volcanoes appear in the middle of a tectonic plate. In 1963, J. Tuzo Wilson proposed the mantle plume hypothesis to explain this phenomenon. Heat transferred from the plume raises the temperature in the lower lithosphere to the above melting point, and magma chambers are formed that feed volcano at the surface. This area is also known as a hot spot or flood basalt. Hotspots exist in Hawaii and Iceland.
The mantle plume hypothesis is useful in understanding the formation of volcanic chains, growth and breakdown of supercontinents, active rifting, the formation of passive volcanic-type continental margins, and the origin of time progressive volcanic chains on oceanic and continental plates. Although the evidence for mantle plumes is largely circumstantial, it still plays a vital role in the processes of plate tectonics.