Model Answer
0 min readIntroduction
The Tertiary period, spanning from approximately 66 to 2.6 million years ago, witnessed significant geological activity in India, including the formation of sedimentary basins and volcanic terrains. These Tertiary rocks are crucial hosts to a variety of economically valuable deposits. The Indo-Gangetic plain, parts of the Himalayas, and coastal regions are particularly rich in these resources. Understanding the genesis and distribution of these deposits is vital for India’s economic development and resource management. This answer will detail the key economic deposits associated with Tertiary rocks in India, outlining their characteristics and significance.
Economic Deposits Associated with Tertiary Rocks of India
Tertiary rocks in India are primarily sedimentary and volcanic in nature, providing favorable conditions for the formation of various economic deposits. These deposits can be broadly categorized as follows:
1. Lignite
- Occurrence: Majorly found in the Neyveli lignite fields of Tamil Nadu (Cuddalore Formation – Miocene epoch), Palana in Gujarat, and parts of Jammu & Kashmir.
- Formation: Formed from the compaction and alteration of peat in swampy environments during the Tertiary period.
- Economic Importance: Used as fuel for power generation, and as a raw material for the production of chemicals.
2. Petroleum and Natural Gas
- Occurrence: Predominantly found in the sedimentary basins of Assam (Numaligarh Formation – Oligocene-Miocene), Gujarat (Cambay Basin – Eocene-Oligocene), and the Krishna-Godavari basin (Cretaceous-Tertiary).
- Formation: Formed from the remains of marine organisms buried under sedimentary layers, subjected to heat and pressure over millions of years.
- Economic Importance: Crucial energy sources, used in transportation, power generation, and as raw materials for petrochemical industries.
3. Bauxite
- Occurrence: Found in the lateritic deposits of the Eastern Ghats (Koraput, Odisha), Western Ghats (Ratnagiri, Maharashtra), and parts of Gujarat. Often associated with Tertiary basalt flows.
- Formation: Formed through intense weathering and leaching of aluminum-rich rocks under tropical conditions.
- Economic Importance: Primary ore for aluminum production, used in various industries like aerospace, packaging, and construction.
4. Iron Ore
- Occurrence: Tertiary iron ore deposits are less common but are found in parts of Rajasthan (e.g., near Bhilwara) and Madhya Pradesh. These are often in the form of oolitic iron ore.
- Formation: Formed through chemical precipitation from iron-rich solutions in shallow marine or lacustrine environments.
- Economic Importance: Essential raw material for the steel industry.
5. Silica Sand
- Occurrence: Found extensively in the coastal regions of India, particularly along the Kerala and Tamil Nadu coasts, derived from the weathering of Tertiary sandstones.
- Formation: Formed from the erosion and deposition of quartz-rich rocks.
- Economic Importance: Used in the glass industry, ceramics, and as a raw material for the production of silicon.
6. Gypsum and Limestone
- Occurrence: Found in sedimentary sequences of the Kutch region (Gujarat) and parts of Rajasthan, often associated with Tertiary marine deposits.
- Formation: Gypsum precipitates from saline water, while limestone is formed from the accumulation of marine organisms.
- Economic Importance: Gypsum is used in cement production and as a soil conditioner, while limestone is a key ingredient in cement, steel, and chemical industries.
| Deposit | Major Occurrence | Tertiary Epoch |
|---|---|---|
| Lignite | Neyveli (Tamil Nadu), Palana (Gujarat) | Miocene |
| Petroleum & Natural Gas | Assam, Gujarat, Krishna-Godavari Basin | Eocene-Oligocene, Miocene |
| Bauxite | Eastern & Western Ghats, Gujarat | Various |
Conclusion
The Tertiary rocks of India are a significant repository of diverse economic deposits, contributing substantially to the nation’s energy resources, industrial raw materials, and overall economic growth. Effective exploration, sustainable extraction practices, and responsible resource management are crucial to maximizing the benefits from these deposits while minimizing environmental impacts. Further geological investigations and technological advancements will be key to unlocking the full potential of these valuable resources in the future.
Answer Length
This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.