Correct Option
The correct option is 1 and 3 only.
Explanation
Glaciers act as powerful agents of erosion in high-altitude and high-latitude regions. Through processes such as plucking and abrasion, they carve out distinctive erosional landforms in the bedrock. Understanding the specific characteristics of these landforms distinguishes them from depositional features.
Statement-wise Analysis
- Statement 1 is Correct: Cirques are the most common landforms in glaciated mountains. They are typically found at the heads of glacial valleys. Morphologically, they are deep, long, and wide troughs or basins characterized by very steep, concave, or vertically dropping high walls at their head and sides. After the glacier melts, water often accumulates in these depressions to form tarn lakes.
- Statement 2 is Incorrect: Horns are erosional landforms, not depositional. They are formed through the headward erosion of cirque walls. When three or more radiating glaciers cut headward until their cirques meet, they create high, sharp-pointed, and steep-sided peaks known as horns (e.g., the Matterhorn in the Alps). Glacial till is unsorted sediment associated with depositional landforms like moraines, not erosional features like horns.
- Statement 3 is Correct: Arêtes are sharp, saw-toothed ridges that separate adjacent glacial valleys or cirques. They form when the divide between the side walls of two cirques narrows due to progressive erosion. These ridges often exhibit a zig-zag outline resembling a saw blade.
Key Takeaway
Key Takeaway: Cirques, Arêtes, and Horns are distinct erosional features of glaciated landscapes formed by the removal of bedrock, whereas landforms created by glacial till (such as moraines and drumlins) are depositional in nature.