Differentiation
Also called: Planetary differentiation · Topic: Origin and Evolution of the Earth and the Solar System · NCERT: Class 11, Ch 2 "The Origin and Evolution of the Earth"
Meaning
Differentiation is the process that split the young Earth into layers. As the Earth's density grew, its inside heated up. Material then separated by weight: heavy iron sank to the centre and lighter material rose towards the surface. The Earth cooled, hardened and shrank, and a crust formed. The result was a crust, mantle, outer core and inner core, each denser than the one above it.
Example
Light rocks such as granite make up the continental crust under the Indian peninsula, for example around Bengaluru in Karnataka. Dense iron and nickel, on the other hand, sank to form the Earth's core.
Don't confuse with
- Evolution of the atmosphere: this happened in three stages: loss of the first atmosphere to the solar wind, degassing, and photosynthesis. Differentiation built the Earth's inner layers and is not a stage in the evolution of the atmosphere.