RAS question
The Gondwana coal fields of India are primarily of which geological age?
Correct answer: (D) Permian-Carboniferous (about 250 million years).
India's Gondwana coal fields are primarily Permian-Carboniferous in geological age, with the main coal seams occurring in Lower and Upper Permian Gondwana sediments.
Explanation
Gondwana coal is the dominant coal category in India: about 98% of India's coal reserves are Gondwana coals, formed in the Permian period about 25 crore years ago. The National Data Repository, Directorate General of Hydrocarbons, Ministry of Petroleum and Natural Gas, Government of India places Gondwana rocks in the Permo-Carboniferous to Early Cretaceous range in the Pranhita-Godavari Valley, and then narrows the coal-bearing layers: Lower Permian Gondwana sediments include coal seams, Middle Permian sediments are largely coal-free, and Upper Permian Gondwanas are again coal-bearing. That is why the exam answer is not a broad younger age but the Permian-Carboniferous association, especially the Permian coal-bearing sequence found in major Gondwana basins such as Damodar, Mahanadi and Godavari valleys.
Why the other options are wrong
- (A) Tertiary coal is a younger category associated with Assam, Meghalaya and Jammu, not the main Gondwana coal-fields sequence.
- (B) Jurassic does occur later in the Gondwana stratigraphic range on the NDR/DGH page, but the coal seams occur in Lower and Upper Permian Gondwana sediments, not Jurassic beds.
- (C) Quaternary is far too recent for the coal formation described here, which belongs to the much older Gondwana-Permian sequence.
Concept
This tests the RAS geography link between India's mineral distribution and geological history. Gondwana coal recurs because it connects coal-field locations with the age and stratigraphy of peninsular basins.