Model Answer
0 min readIntroduction
Uranium, a crucial element for nuclear power generation, is a naturally occurring radioactive metal found in low concentrations in various rocks and minerals. India possesses significant uranium reserves, estimated at around 0.28% of the world’s total, though its resource base is relatively limited compared to countries like Australia, Kazakhstan, and Canada. The exploration and exploitation of these resources are vital for India’s energy security. Uranium mineralization in India is diverse, occurring in various geological settings, and is primarily associated with Precambrian rocks, Gondwana sediments, and coastal placer deposits. Understanding the mineralogy and genesis of these deposits is crucial for effective exploration and resource management.
Uranium Mineralogy in India
The primary uranium-bearing minerals in India include:
- Uraninite (UO2): The most important uranium mineral, often associated with pyrite, chalcopyrite, and other sulfide minerals.
- Coffinite (U(SiO4)1-x(OH)4x): A hydrous uranium silicate, commonly found in sedimentary environments.
- Carnotite (K2(UO2)2(VO4)2·3H2O): A potassium uranium vanadate, typically found in sandstone-type deposits.
- Brannerite ((U,Th)TiO5): A uranium-thorium titanosilicate, often associated with alkaline igneous rocks.
- Rosinite (Ca(UO2)2(PO4)2·11H2O): A calcium uranium phosphate, found in sedimentary environments.
The specific mineral assemblage varies depending on the geological environment and the physicochemical conditions during mineralization.
Genesis of Uranium Mineralization in India
Uranium mineralization in India can be broadly classified into several genetic types, each with distinct geological characteristics:
1. Precambrian Unconformity-Related Deposits
These are the most significant uranium deposits in India, accounting for a large proportion of the country’s uranium reserves. They are typically found in the Proterozoic basins overlying Archean crystalline basement. The key features include:
- Geological Setting: Occur along unconformities between Archean granites/gneisses and overlying Proterozoic sedimentary rocks (sandstones, shales, conglomerates).
- Genesis: Uranium is leached from the granitic basement during weathering and transported by groundwater. It precipitates at the unconformity surface due to changes in redox conditions and pH.
- Examples: Jaduguda, Narwapahar, Bhatin (East Singhbhum district, Jharkhand). These deposits are hosted within the Singhbhum Granite-Gondwana sequence.
2. Sandstone-Type Deposits (Gondwana Sediments)
These deposits are associated with the Permian-Jurassic Gondwana sediments, particularly in the Pranhita-Godavari Valley.
- Geological Setting: Found within coarse-grained sandstones and conglomerates of the Gondwana group.
- Genesis: Uranium is sourced from the weathering of surrounding granitic terrains and transported by fluvial systems. Carnotite is the dominant uranium mineral.
- Examples: Lambapur, Kesorai, and Peddagudem in Andhra Pradesh and Telangana.
3. Vein-Type Deposits
These deposits are less common but significant in certain areas.
- Geological Setting: Occur in quartz veins associated with fault zones and shear zones within granitic and metamorphic rocks.
- Genesis: Uranium is transported in hydrothermal fluids and precipitates along fractures and fissures.
- Examples: Hazaribagh area, Jharkhand.
4. Coastal Placers
These deposits are found along the coastal stretches of Kerala and Tamil Nadu.
- Geological Setting: Heavy mineral sands containing monazite, ilmenite, rutile, and zircon, with minor amounts of uraninite.
- Genesis: Uranium is derived from the weathering of rocks in the Western Ghats and transported by rivers to the coast, where it is concentrated in placer deposits.
- Examples: Chavara, Manavalakurichi.
5. Alkaline Igneous Related Deposits
These are relatively new areas of exploration.
- Geological Setting: Associated with alkaline igneous complexes.
- Genesis: Uranium is concentrated during the magmatic differentiation process.
- Examples: Several occurrences in Rajasthan.
Regional Distribution of Uranium Deposits
| Region | Dominant Deposit Type | Key Deposits |
|---|---|---|
| Singhbhum (Jharkhand) | Precambrian Unconformity-Related | Jaduguda, Narwapahar, Bhatin |
| Pranhita-Godavari Valley (Telangana & Andhra Pradesh) | Sandstone-Type | Lambapur, Kesorai, Peddagudem |
| Rajasthan | Vein-Type, Alkaline Igneous | Various occurrences in the state |
| Kerala & Tamil Nadu | Coastal Placers | Chavara, Manavalakurichi |
Conclusion
Uranium mineralization in India is geologically diverse, with Precambrian unconformity-related and sandstone-type deposits being the most economically significant. Understanding the mineralogy and genesis of these deposits is crucial for effective exploration strategies and sustainable resource management. Continued research and exploration, coupled with advancements in extraction technologies, are essential to meet India’s growing energy demands and reduce its reliance on imported uranium. The exploration of less conventional deposit types, like those associated with alkaline igneous rocks, also holds promise for future resource expansion.
Answer Length
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