The correct answer to this question is Option 4: 1, 2 and 3.
Shale gas is a type of natural gas that is trapped within shale rock formations deep underground. In recent years, shale gas has emerged as an important source of natural gas, and many countries around the world, including India, are actively exploring their shale gas reserves.
In India, shale gas resources are primarily found in three regions: the Cambay Basin, the Cauvery Basin, and the Krishna-Godavari Basin.
1. Cambay Basin:
The Cambay Basin is located in the western part of India, primarily in the state of Gujarat. It is one of the most promising regions for shale gas exploration in India, with estimates suggesting that the basin could contain as much as 2.5 trillion cubic feet of shale gas reserves. The Cambay shale is a part of the Deccan Traps, which is a large igneous province consisting of flood basalts. The shale is located at depths ranging from 1000 to 3500 meters.
2. Cauvery Basin:
The Cauvery Basin is located in southern India, primarily in the states of Tamil Nadu and Karnataka. The shale formations in the Cauvery Basin are believed to be similar to those in the United States, which has significant shale gas resources. The shale in the Cauvery Basin is located at depths ranging from 2000 to 3500 meters. The Cauvery Basin is estimated to contain shale gas reserves of around 50 trillion cubic feet.
3. Krishna-Godavari Basin:
The Krishna-Godavari Basin is located in the eastern part of India, primarily in the state of Andhra Pradesh. It is one of the largest sedimentary basins in India and is estimated to contain significant shale gas resources. The shale in the Krishna-Godavari Basin is located at depths ranging from 2000 to 4000 meters. The basin is estimated to contain shale gas reserves of around 70 trillion cubic feet.
In conclusion, all three regions listed in the question, the Cambay Basin, the Cauvery Basin, and the Krishna-Godavari Basin, are known to have shale gas resources in India. Therefore, the correct answer is Option 4: 1, 2 and 3.