Which of the following coalfields contain tertiary coals? A. Raniganj coalfields, West Bengal B. Neyveli coalfields, Tamil Nadu C. Talchir coalfields, Odisha D. Makum coalfields, Assam Choose the correct answer from the options given below:

The correct answer is: 4) B and D only Key Points Neyveli coalfields, Tamil Nadu: This statement is correct . The Neyveli coalfields are known for lignite deposits. Lignite, being a form of brown coal, typically forms in the Tertiary period, making this coalfield a source of tertiary coal. Makum coalfields, Assam: This statement is correct . The Makum coalfields are also known for their tertiary coal deposits. Assam is home to significant deposits of lignite and lesser rank coals that have formed during the Tertiary period. Raniganj coalfields, West Bengal: This statement is incorrect . The Raniganj coalfields are part of the Damodar Valley and are well known for their Gondwana coals, which are older than tertiary coals. Talchir coalfields, Odisha: This statement is incorrect . The Talchir coalfields also belong to the Gondwana coal group which is much older than the tertiary period. Additional Information Types of Coals: Coals are classified into different types based on their geological age, carbon content, and other properties. The main types include Anthracite, Bituminous Coal, Sub-bituminous Coal, and Lignite. Lignite, often referred to as brown coal, is the lowest rank of coal and is typically found in tertiary deposits. Geological Age of Coal: Coal formed from plant material under high pressure and temperature over millions of years. The Tertiary period occurred from about 66 to 2.6 million years ago, after the much older Gondwana period, which was around 350 to 290 million years ago. The coal deposits can thus be categorized as either Gondwana or Tertiary based on their age. Significance of Tertiary Coal: Tertiary coals, such as lignite, are important for many energy industries because they are plentiful and widely distributed, even though they have a lower carbon content and calorific value compared to older, higher-rank coals.