All questions of Landforms of Glaciation for UPSC CSE Exam

Explanation:

Terminal moraines are ridges of debris deposited at the glacier's end by the moving ice sheet or glacier. They are formed when a glacier or ice sheet reaches its maximum extent during the advance phase and deposits the debris it has eroded from the valley floor and sides as well as the material it has picked up along its path. Terminal moraines mark the furthest extent of glacier or ice sheet advance and are typically found at the lower end of the glacier's snout.

Composition of Terminal Moraines:

Terminal moraines are composed of a mix of materials, including boulders, gravel, sand, and clay. The size and composition of the debris depend on the nature of the underlying bedrock, the strength of the glacier, and the distance the debris has traveled.

Formation of Terminal Moraines:

Terminal moraines are formed by the accumulation of debris at the glacier's snout as it melts or retreats. As the ice melts, it deposits the debris that it has carried along in a pile at its end. The pile of debris gradually builds up, forming a ridge or ridge-like feature.

Location of Terminal Moraines:

Terminal moraines are typically found at the lower end of the glacier's snout, marking the furthest extent of glacier or ice sheet advance. They can also be found in other locations where glaciers or ice sheets have been active, including valleys, fjords, and coastal plains.

Conclusion:

In conclusion, terminal moraines are made up of the coarse debris deposited at the edge of an ice sheet or glacier. They are formed by the accumulation of debris at the glacier's snout as it melts or retreats and are typically found at the lower end of the glacier's snout, marking the furthest extent of glacier or ice sheet advance.

< b="" />Explanation:< />

The correct answer is option 'D', neither of them.

< b="" />Statement 1:< />
The statement is correct. When two corries cut back on opposite sides of a mountain, knife-edged ridges are formed called aretes. A corrie is a bowl-shaped hollow found on the side of a mountain, formed by glacial erosion. As the glaciers move down the mountain, they erode the sides of the corrie, creating steep knife-edged ridges called aretes. These aretes are often narrow and sharp, resembling the edge of a knife.

< b="" />Statement 2:< />
The statement is incorrect. When three or more cirques cut back together, their ultimate recession will not necessarily form an angular horn or pyramidal peak. A cirque is a bowl-shaped hollow found at the head of a glacier, formed by glacial erosion. As the glaciers move down the mountain, they erode the sides and bottom of the cirque, creating a steep-sided hollow. If three or more cirques cut back together, they may form a broad, rounded peak known as a horn. This is characterized by steep slopes on all sides. However, the ultimate shape of the peak will depend on various factors such as the nature of the rock, the direction of glacial movement, and the erosional processes involved. It is not necessary that it will always form an angular horn or pyramidal peak.

Therefore, both statements are not correct.

Introduction:
Boulder clay is a type of glacial deposit that is formed by the movement and melting of glaciers. It is an unsorted deposit, meaning it contains a range of different eroded materials. In this response, we will examine the two statements provided and determine which one(s) are correct.

Statement 1: This is an unsorted glacial deposit comprising a range of eroded materials
This statement is correct. Boulder clay is indeed an unsorted glacial deposit. When glaciers move, they pick up large amounts of sediment, including rocks, stones, clay, and sand, from the surfaces they pass over. As the glaciers melt, they deposit this sediment in the form of boulder clay. The materials within boulder clay can vary greatly in size, shape, and composition, as they have been eroded and transported by the glacier.

Statement 2: It is spread out in mounds
This statement is incorrect. Boulder clay is not typically spread out in mounds. Instead, it forms a relatively flat or gently undulating landscape. This is because boulder clay is deposited by glaciers as they melt and retreat, leading to a relatively uniform layer of sediment covering the ground. This layer can be several meters thick and can extend over large areas, creating a distinct glacial landscape.

Conclusion:
In conclusion, statement 1 is correct while statement 2 is incorrect. Boulder clay is an unsorted glacial deposit consisting of a range of eroded materials. However, it is not spread out in mounds but rather forms a relatively flat or gently undulating landscape.

Glacial Influences on Economic Activities
Glacial influences significantly impact men's economic activities in various ways, shaped by factors such as intensity of glaciation, relief of the region, and the erosional or depositional nature of glacial processes.
1. Intensity of Glaciation
- The intensity of glaciation determines the extent of glacial coverage and the climatic conditions of the region.
- Areas with intense glaciation may have limited agricultural potential and can drive communities toward alternative economic activities like tourism, mining, and hydroelectric power due to the landscape's unique features.
2. Relief of the Region
- The relief or topography of a region influences accessibility and types of economic activities.
- Steep, rugged terrains may restrict agricultural practices while promoting activities like forestry, mining, and adventure tourism.
3. Erosional or Depositional Nature
- The erosional nature of glaciers shapes the landscape, creating valleys and fjords that can affect settlement patterns and infrastructure development.
- Conversely, depositional features like moraines and glacial till can enrich soil quality, supporting agriculture in certain areas.
Conclusion
In conclusion, all three factors—intensity of glaciation, relief of the region, and the erosional or depositional nature—play a crucial role in determining how economic activities are structured in glaciated regions. The interplay of these elements creates diverse opportunities and challenges that shape human livelihoods. Therefore, the correct answer is option 'D': All of them.

Explanation:

Ribbon Lakes:
- Ribbon lakes are long, narrow lakes that form in a glacial trough.
- They are created by glaciers moving through and reshaping the landscape.
- The distinctive shape of ribbon lakes is due to the erosion caused by the moving glacier.

Also referred to as:
- Trough lakes: Ribbon lakes are sometimes referred to as trough lakes because of their formation in glacial troughs.
- Finger lakes: This term is also used to describe ribbon lakes due to their long, narrow shape resembling a finger.

Correct Answer: Both of them
- Since ribbon lakes are also known as trough lakes and finger lakes, the correct answer is option 'C' - Both of them.

Understanding Hanging Valleys
Hanging valleys are distinctive geological features formed by the differential erosion of valleys affected by glacial activity. Here’s a detailed explanation:
Formation Process
- Erosion Rates: The main valley, which hosts a larger glacier, experiences more significant erosion due to the greater weight and movement of the ice. This results in a deeper, more pronounced valley floor.
- Tributary Valleys: In contrast, tributary valleys, which contain smaller glaciers, erode less intensely. As a result, they remain at a higher elevation compared to the main valley after glacial retreat.
Consequences of Erosion
- Waterfalls: When the ice melts away, the streams from these tributary valleys flow into the main valley. Since the tributary valleys are elevated, the water cascades downwards, creating stunning waterfalls.
- Visual Dynamics: The abrupt drop creates striking landscapes often admired in national parks and regions with glaciated terrain.
Importance of Hanging Valleys
- Ecological Significance: These areas often support unique ecosystems due to their varied elevation and microclimates.
- Geological Indicators: Hanging valleys serve as indicators of past glacial activity and help geologists understand the dynamics of glacial erosion and landscape formation.
In conclusion, hanging valleys exemplify the powerful forces of glacial erosion, leading to breathtaking waterfalls and unique geological features that contribute to the natural beauty of mountainous regions.

Explanation:

The correct answer is option D, neither of them. None of the statements is correct.

Let's analyze each statement:

1. By plucking, the glacier scratches, scrapes, polishes, and scours the valley floor with the debris frozen into it.

Plucking is a process by which a glacier erodes the underlying rocks by freezing onto them and then pulling them out as the glacier moves. However, plucking does not involve scratching, scraping, polishing, or scouring the valley floor. These processes are more closely associated with abrasion, which is the grinding action of rocks and debris carried by the glacier against the valley floor. Plucking and abrasion are distinct processes, and the statement incorrectly combines the two.

2. By abrasion, the glacier freezes the joints and beds of the underlying rocks, tears out individual blocks, and drags them away.

Abrasion is the process by which rocks and debris carried by a glacier scrape and grind against the valley floor, causing erosion. However, the statement is incorrect in stating that the glacier freezes the joints and beds of the underlying rocks. Freezing of joints and beds is associated with frost wedging, which is a process that occurs in cold climates when water seeps into cracks in rocks and freezes, causing the cracks to widen and eventually break apart. The tearing out of individual blocks and dragging them away is more closely associated with plucking, not abrasion.

In summary, statement 1 incorrectly combines plucking and abrasion processes, and statement 2 incorrectly attributes freezing of joints and beds to abrasion. Therefore, neither of the statements is correct.

Erratics
Erratics are large rocks or boulders that have been transported and deposited by glaciers. They are typically composed of materials that are entirely different from those found in the region where they are located. These rocks can range in size from small pebbles to massive boulders, and they are often found in areas far away from their original source.

Statement 1: They are called erratics because they are composed of materials entirely different from those of the region in which they are found
This statement is correct. Erratics are called erratics precisely because they are made up of materials that are different from the surrounding region. These materials are often distinct and can provide valuable insights into the geological history of an area. For example, an erratic composed of granite in an area where the bedrock is primarily limestone indicates that the rock must have been transported from a different location.

Statement 2: Such erratics are most useful in tracing the source and direction of the ice movement
This statement is also correct. Erratics are extremely useful in tracing the source and direction of ice movement. By studying the composition and characteristics of erratics, scientists can determine the type of rock and its origin. This information can then be used to reconstruct the movement of glaciers and ice sheets. The presence of erratics in a particular area can indicate the direction in which ice was flowing and provide evidence of past glacial activity.

Erratics can also help in identifying the extent of glaciation in an area. The distribution of erratics can give insights into how far the ice sheet extended during a particular glaciation event. By mapping the locations of erratics, scientists can create a picture of the past ice movement patterns and the areas that were affected.

Conclusion
In conclusion, both statements are correct. Erratics are composed of materials different from their surroundings, and they are valuable in tracing the source and direction of ice movement. These rocks provide important clues about past glacial activity and can help scientists reconstruct the geological history of an area.

Drumlins: Explanation

Drumlins are elongated, oval-shaped hills that are composed of boulder clay. They are formed by the movement of glaciers. The drumlins are aligned in the direction of the ice flow, which is on the downstream side. They are low hills that can vary from a few yards to 400 feet in height and maybe a mile or two long. They appear a little steeper at the onset side and taper off at the leeward end.

Formation of Drumlins

The formation of drumlins is still not fully understood, but it is believed that they are formed by the action of glaciers. The glaciers move over the land, picking up and carrying rocks and sediments. As the glacier moves, it creates a mound of sediment in front of it. This mound is known as a drumlin. The drumlin is formed by the accumulation of sediments and rocks that are carried by the glacier. The sediments and rocks are deposited on the ground, and then the glacier moves over them, forming a mound.

Characteristics of Drumlins

- Elongated, oval-shaped hills
- Composed of boulder clay
- Aligned in the direction of the ice flow
- Low hills varying from a few yards to 400 feet in height and maybe a mile or two long
- Steeper at the onset side and taper off at the leeward end

Conclusion

In conclusion, drumlins are elongated, oval-shaped hills that are composed of boulder clay. They are formed by the movement of glaciers and are aligned in the direction of the ice flow on the downstream side. They are low hills that can vary in height and length and appear steeper at the onset side and taper off at the leeward end.

Castle Rock of Edinburg: A Classic Example of Crag and Tail
Castle Rock in Edinburgh is a prominent geological feature that exemplifies the formation known as a crag and tail. Here’s a detailed explanation:
What is a Crag and Tail?
- A crag and tail is a landform created by glacial erosion.
- It consists of a hard, resistant rock (the crag) that has been shaped by the movement of glaciers, often resulting in steep cliffs.
- The softer material behind the crag (the tail) is typically a gentle slope formed from the sediment that was deposited by the glacier.
Formation of Castle Rock
- Castle Rock was formed during the last Ice Age when glaciers moved across the landscape.
- As the glacier advanced, it eroded the softer rock and soil, leaving behind the harder volcanic rock of the Castle Rock as a prominent feature.
- The tail, made of glacial till, extends downhill from the crag, demonstrating the classic characteristics of a crag and tail formation.
Significance of Castle Rock
- It provides a striking visual contrast against the surrounding landscape, contributing to Edinburgh’s dramatic skyline.
- The geological history of Castle Rock also offers insights into the processes of glaciation and erosion that shaped much of Scotland's topography.
In summary, Castle Rock of Edinburgh serves as an excellent example of a crag and tail, showcasing the effects of glacial activity on the landscape and highlighting the interplay between resistant and softer geological materials.