Question.
Mention briefly the geological history of India with reference to eras, systems, and associated landforms, rocks, and Minerals with examples. ( 63rd BPSC, 2019)
Answer.
Geological history means the systematic study of the development of a landmass since its formation.
The geological history of India provides us a lot of information like it tells us how is the geological structure of India, how many types of rock systems are there, what is the mineral availability in different areas, and the landforms here during different phases. When and how did development happen?
In terms of era, the geological history of India can be divided into the following eras.
- Archean era (4.6 billion years to 600 million years)
- Paleozoic Era (600 million to 230 million years)
- Mesozoic Era (230 million years to 65 million years)
- Cenozoic Era (65 million years to the present day)
Archean Era ( 4.6 Billion years to 600 Million years):
Systems:
Under the Archean Era, there are two rock systems in India.
- Archaean rock system (4.6 billion to 1.8 billion years)
- Puranic Rock Systems (1.8 billion years to 600 million years)
Archean rock system (4.6 billion to 1.8 billion years):
Associated landforms:
The following landforms formed during the Archean era:
- Eastern Ghats
- Western Ghats
- Bundelkhand
Rocks:
Two types of rocks formed during this era:
- Archean Gneiss (the base of the peninsula)
- Dharwad Rocks (Metamorphic Sedimentary)
Minerals:
- No remains of fossils are found in this age.
- Important minerals like gold, iron ore, silver, dolomite, zinc, silver, etc.
- For example, the Kolar gold mines belong to the Archaean era and the Dharwad rock system.
Puranic Rock Systems (1.8 billion years to 600 million years):
Associated landforms:
- Vindhya Mountains
- Cuddapah region of Karnataka
Rocks:
It is further divided into two parts:
- Cuddapah Rock System
- Vindhya Rock System
Minerals:
- No fossil records are found.
- Famous minerals sandstone, lime, ornamental stone, etc. are found.
Paleozoic Era (600 million to 230 million years):
Systems :
- The Dravidian rock system belongs to the Paleozoic era,
Associated landforms:
- No significant landforms developed during this period.
- Pangea was broken during this period.
Rocks:
- Carboniferous rocks are the rocks of this period.
Minerals:
- The high quality of coal in India developed from Carboniferous rocks.
Mesozoic Era (230 million years to 65 million years) and Cenozoic Era (65 million years to the present day):
Systems :
The Aryan rock system dates back to the Mesozoic era and the Cenozoic era.
Associated landforms:
- Development of rift in Damodar, Mahanadi, Mahanadi.
- The Deccan Traps were formed at the end of the Mesozoic Era.
- desert formation
- Formation of Himalayas
- Formation of the Great Indian Northern Plains
Rocks:
The following types of rocks developed during this period:
- Gondwana Rocks
- Deccan Rocks (Saurashtra, Malwa Plateau)
- Tertiary and Quaternary rocks (for example, Himalayan rocks)
Minerals:
- 90% of Indian coal was related to Gondwana rocks.
- Other minerals like sandstone, slate, etc. are found in the Aryan rock system.
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