The correct option is (b).
Explanation
Loess is a geomorphological feature formed by the accumulation of wind-blown dust. It is an extensive, unstratified, geologically recent deposit of silty or loamy material that is usually buff or yellowish in color.
Statement-wise Analysis:
- Statement 1 is Incorrect. Loess is not formed by heavy rocks. It consists of fine-grained materials such as silt and clay. Because these particles are extremely light, they are carried in suspension by the wind over very long distances, often hundreds or thousands of kilometers from their source. Heavy rocks are typically moved by traction or saltation over short distances and do not form loess.
- Statement 2 is Correct. Loess is a classic example of an aeolian (wind) depositional landform. It forms when the wind loses velocity and the suspended dust particles settle over a vast area, creating thick blankets of sediment.
- Statement 3 is Incorrect. Large deposits of loess are primarily found in north-western China (the Loess Plateau), the Pampas of Argentina, central Europe, and parts of the United States (Mississippi Valley). Antarctica is predominantly covered by ice sheets and is not characterized by large loess deposits.
Key Takeaway:
Loess is a wind-deposited accumulation of fine silt and clay, transported in suspension over long distances. The most extensive loess deposits in the world are found in the Loess Plateau of China.