Mantle
Topic: Interior of the Earth: Earthquakes, Volcanoes and the Layered Earth · NCERT: Class 9, Ch 2 "Shaping of the Earth's Surface"; Class 11, Ch 3 "Interior of the Earth"
Meaning
The mantle is the layer between the crust and the core. It runs from the Moho down to about 2,900 km. It makes up about 84 per cent of the earth's volume and is denser than the crust. It is made of silicate rock rich in iron and magnesium. Most of it is solid. But the upper part, the asthenosphere (down to about 400 km), is weak, plastic (able to flow slowly) and partly molten. The plates move over this layer, and it is the main source of magma.
Example
Magma from the upper mantle feeds Barren Island volcano in the Andaman Sea, about 140 km north-east of Port Blair. It is India's only confirmed active volcano.
Don't confuse with
- Lithosphere: the lithosphere includes only the uppermost mantle, together with the crust, and it is rigid. The asthenosphere below it is weak and plastic.
Related concepts
- Crust
- Oceanic crust
- Continental crust
- Conrad discontinuity
- Mohorovicic discontinuity
- Asthenosphere
- Lithosphere