Mantle plume
Topic: Continental Drift, Sea-floor Spreading and Plate Tectonics · NCERT: Beyond NCERT
Meaning
A mantle plume is a column of unusually hot rock that rises slowly from deep inside the mantle. As it nears the surface, the pressure drops and part of the rock melts. The magma feeds hotspot volcanoes and huge lava floods. The plume stays nearly fixed while the plate above moves. So it leaves a line of volcanoes that get older the farther they are from the plume. This topic is beyond NCERT.
Example
The Reunion plume made the Deccan Traps of western and central India. As India moved north, it left behind the Chagos-Laccadive Ridge (Lakshadweep, Maldives, Chagos). The hotspot now lies under Reunion Island. The Kerguelen plume made the Ninety East Ridge in the Indian Ocean.
Don't confuse with
- Convection cell: a large loop of mantle movement (rise, spread, cool, sink) thought to help drive the plates. A plume is a narrow column of hot rock that feeds volcanoes at a single spot.