Geomorphology: UPSC Previous Year Questions (Geography)

Explanation

Statement 1 is correct: The distinctive red colour is one of the key characteristics of laterite soils. It appears red due to the high concentration of iron oxides. In tropical climates, heavy rainfall causes intense leaching, washing away silica and other bases while leaving behind iron and aluminum oxides, which give the soil its distinctive red color.

Statement 2 incorrect: Laterite soils are poor in nitrogen, phosphorus, and potash (potassium). The intense leaching caused by heavy rainfall in tropical regions washes away these soluble nutrients.

Statement 3 is incorrect: Laterite soils are primarily found in the humid tropical regions of India, such as the Western Ghats, parts of Eastern Ghats, and some northeastern states. Rajasthan and Uttar Pradesh (UP) have a drier climate which is not suitable for the formation of laterite soils.

Statement 4 is correct: The agro-climatic conditions of laterite soils support the cultivation of crops such as tapioca, cashew nuts, groundnut, coffee, and rubber. These crops are well-adapted to the moisture-retaining and nutrient-poor nature of laterite soils.

Explanation

Statement 1 is incorrect: The Gondwana beds are primarily famous for containing coal reserves, with nearly 98% of India’s coal reserves found in them. They are not significant for natural gas reserves. Natural gas in India is more commonly associated with other formations such as sedimentary basins such as the Cambay Basin or the Krishna-Godavari Basin.

Statement 2 is correct: Kodarma in Jharkhand is a well-known region for mica production, which has been an important mineral in India’s mineral resources. Mica is found abundantly here and Kodarma is often referred to as the "mica capital" of India.

Statement 3 is incorrect: The Dharwar system of rocks is not known for petroleum production. The Dharwar rocks are particularly valuable for metallic minerals like high-grade iron ore, manganese, and copper. Petroleum is not found in the Dharwar rock system but in other formations like the Cambay Basin or the Rajasthan Basin.

Explanation

Factors of The Dynamic Changes of the Earth:

Electromagnetic radiation from the sun, particularly in the form of solar energy, drives atmospheric and surface processes such as weathering, erosion, and the water cycle. These processes contribute to the continuous reshaping of Earth’s surface. Geothermal energy originates from Earth’s internal heat, which fuels volcanic activity and drives plate tectonics. These internal processes lead to the formation of new landforms, mountain building, and seafloor spreading, all of which dynamically alter Earth’s surface. Gravity influences the movement of water, sediments, and tectonic plates. It plays a crucial role in processes like mass wasting (landslides), river flow, and glacial movement which contributes to the dynamic changes on Earth’s surface. The movement of tectonic plates leads to continental drift, mountain formation, earthquakes, and volcanic activity. Rotation of the Earth causes the Coriolis effect, which deflects moving air and water, influencing weather patterns, ocean currents, and thus affecting erosion and deposition. It also contributes to the tides. Revolution of the Earth around the sun, combined with its axial tilt, causes the seasons. Seasonal variations in temperature and precipitation influence weathering, erosion, and the activity of living organisms, all of which contribute to surface changes. Thus, all of the above are responsible for bringing dynamic changes on the surface of the earth. Since all the listed factors contribute to dynamic changes, the correct answer is option (d).