The correct option is Iron ore.
Explanation
The geological structure of a region dictates the types of minerals found there. In India, the Dharwar system of rocks constitutes the oldest metamorphosed sedimentary rocks and is economically the most significant geological formation because it serves as the primary host for metallic minerals.
Detailed Analysis
- Iron ore Iron ore: This is Correct. The Dharwar rock system is the storehouse of metallic minerals in India. It contains the largest and richest deposits of high-grade iron ore (Hematite and Magnetite), as well as manganese, copper, lead, and gold. The major iron ore belts of Odisha, Jharkhand, Chhattisgarh, and Karnataka are located within this system.
- Limestone Limestone: This is Incorrect. Limestone is primarily a sedimentary rock associated with the Vindhyan system and the Cuddapah system. The Vindhyan system is famous for building materials like limestone, sandstone, and marble.
- Mica Mica: This is Incorrect. While Mica is found in metamorphic terrains (schists and gneisses) often associated with Archean rocks, the specific distinction of the Dharwar system is its massive metallic ore reserves. Mica is most notably extracted from pegmatite veins in the Bihar-Jharkhand belt.
- Gypsum Gypsum: This is Incorrect. Gypsum is a sedimentary mineral typically associated with younger geological formations, such as the Tertiary rocks found in Rajasthan and Gujarat.
Key Takeaway
The Dharwar Rock System is the most metalliferous rock system in India, hosting the country's major deposits of Iron ore, Manganese, Gold, and Copper.