Classification of Indian Rock System

⦿ India’s geographical land area can be classified into the:- 

Archaean rock system

The Purana rock system

The Dravidian rock system

The Aryan rock system.

Archaean rock system

⦿ The Archaean rock system is also known as Pre- Cambrian rocks.

⦿ It is the oldest rock system.

⦿ They are Archaean Gneisses and Archaean Schists which are formed nearly 4 billion years ago.

⦿ They are formed during the pre-Cambrian era by the cooling and solidification of the upper surface of Earth’s crust.

⦿ They are azoic, which means they are formed when magma underneath the Earth’s surface solidified and has no fuel.

⦿ They are also faulted and generally have a well-defined foliated structure which means they are crystalline and form thin sheets.

⦿ This type of rock is found in Karnataka, Tamil Nadu, Madhya Pradesh, Orrisa, Southern -eastern part of Rajasthan, and the Chhotanagpur plateau of Jharkhand.

⦿ They contain gneisses (which range from granite to gabbro) and schists (crystalline rocks such as mica, talc, etc.).

⦿ These rocks have metallic and non-metallic minerals like copper, tin, graphite, lead, zinc, etc.

⦿ They are also known as “Basement complexes” as they are the oldest and form the base for new layers.

⦿ In this, volcanic rocks are also found inside when going in deep which results in plutonic intrusions.

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