Degassing
Also called: Outgassing · Topic: Origin and Evolution of the Earth and the Solar System · NCERT: Class 11, Ch 2 "The Origin and Evolution of the Earth"
Meaning
Degassing is the release of gases and water vapour from the Earth's hot interior. It happened as the Earth cooled, and constant volcanic eruptions helped it along. It built the Earth's second atmosphere, made of water vapour, nitrogen, carbon dioxide, methane and ammonia, with very little free oxygen. It is the second of the three stages in the evolution of the atmosphere.
Example
Barren Island in the Andaman Sea is India's only active volcano. When it erupts, it gives off water vapour and gases such as carbon dioxide. This is a small, modern version of the degassing that filled the early atmosphere.
Don't confuse with
- Differentiation: this is the sorting of the Earth's interior into crust, mantle and core by weight. Degassing is the escape of gases out of the interior to form the air.