Which of the following is not correct?

1. Fundamentals of Glacial Geomorphology (basic)

To understand glacial geomorphology, we must first view a glacier not just as a block of ice, but as a powerful geomorphic agent. Unlike rivers that flow quickly and cut narrow channels, glaciers are massive, slow-moving bodies of ice that exert enormous pressure on the landscape. This movement, driven by gravity and gradients, allows glaciers to remove, transport, and deposit earth materials, effectively reshaping high mountains into low hills over geological time FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.), Chapter 6, p.38. These are often referred to as cryogenic processes, which include cycles of glaciation (cold periods) and inter-glaciation (warmer periods when ice retreats) Environment and Ecology, Majid Hussain, Climate Change, p.12.

One of the most fascinating aspects of glacial landforms is their 'parasitic' nature. Glaciers rarely create entirely new valleys; instead, they 'live off' and modify pre-existing fluvial (river-cut) landscapes. A classic example is the transformation of a narrow, V-shaped river valley into a broad, steed-sided U-shaped Glacial Trough. Because the glacial mass is so heavy and moves as a solid block, its erosional activity is uniform across the valley floor and walls, widening and deepening the landscape simultaneously Physical Geography by PMF IAS, Manjunath Thamminidi, Chapter 17, p.231.

When we look at specific erosional landforms, we see the 'fingerprints' of ice. Cirques (or corries) are deep, long, and wide amphitheater-like basins found at the heads of glacial valleys FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.), Chapter 6, p.54. Another striking feature is the hanging valley. This occurs because a massive main glacier erodes its valley much deeper than its smaller tributary glaciers. When the ice melts, the tributary valley is left stranded at a higher elevation, often creating spectacular waterfalls as streams drop into the main trough below.

Finally, we must distinguish between how glaciers drop their load. When a glacier melts, it leaves behind Glacial Till—an unassorted, messy mix of coarse and fine angular debris. However, if that debris is carried and dropped by meltwater streams, it forms Outwash Deposits. Unlike till, outwash is roughly stratified (layered) and the rocks are more rounded due to the action of flowing water FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.), Chapter 6, p.55.

Feature	Glacial Till	Outwash Deposits
Agent	Directly by Ice	Meltwater Streams (Glacio-fluvial)
Sorting	Unassorted/Unstratified	Roughly Stratified/Sorted
Shape	Angular to sub-angular	Somewhat rounded

Sources: FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.), Chapter 6: Landforms and their Evolution, p.38, 54, 55; Physical Geography by PMF IAS, Manjunath Thamminidi, Chapter 17: Major Landforms and Cycle of Erosion, p.231; Environment and Ecology, Majid Hussain (Access publishing 3rd ed.), Climate Change, p.12

2. Major Erosional Landforms: Cirques and Horns (intermediate)

To understand glacial landscapes, we must first look at the mountain peaks where glaciers are born. Unlike the smooth, rounded hills often carved by rain and rivers, glaciated mountains are characterized by sharp, jagged, and dramatic features. The most fundamental of these is the Cirque (also known as a Corrie in Scotland or a Cwm in Wales). Think of a cirque as a massive, natural armchair carved into the side of a mountain. It is a deep, long, and wide basin with very steep, almost vertical walls on three sides and an open side where the glacier flows out FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Chapter 6: Landforms and their Evolution, p. 54.

The formation of a cirque is a masterpiece of two glacial processes: plucking and abrasion. As ice accumulates in a small depression, it freezes onto the rocks of the back wall. When the glacier moves, it literally "plucks" or pulls away large chunks of rock, making the wall steeper. Simultaneously, the weight of the moving ice grinds against the floor of the depression (abrasion), scooping it out deeper Certificate Physical and Human Geography, Landforms of Glaciation, p. 61. Once the glacier melts away, these basins often fill with water to form beautiful high-altitude lakes known as Tarn lakes or cirque lakes.

As these cirques continue to erode headward (backwards into the mountain), they begin to meet. This leads to the formation of sharper, more skeletal features:

• Arêtes: When two cirques erode toward each other from opposite sides of a ridge, the dividing wall becomes a narrow, knife-edged ridge.
• Horns: When three or more cirques erode headward until their walls meet at a single central point, they leave behind a sharp, pointed, pyramidal peak known as a Horn Physical Geography by PMF IAS, Chapter 17: Major Landforms and Cycle of Erosion, p. 231. The famous Matterhorn in the Alps is the textbook example of such a peak.

Landform	Visual Analogy	Key Characteristics
Cirque	Armchair / Scoop	Steep back-walls, flat floor, may hold a Tarn lake.
Arête	Knife-edge	Narrow ridge separating two adjacent cirques.
Horn	Pyramid	Sharp peak formed by the meeting of 3+ cirques.

Sources: FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Chapter 6: Landforms and their Evolution, p.54; Certificate Physical and Human Geography, Landforms of Glaciation, p.61; Physical Geography by PMF IAS, Chapter 17: Major Landforms and Cycle of Erosion, p.231

3. The Glacial Trough: U-shaped Valleys (intermediate)

When we look at high-altitude or high-latitude landscapes, one of the most majestic sights is the Glacial Trough. Unlike the narrow, sharp V-shaped valleys carved by rivers NCERT Class XI, Chapter 6, p.48, a glacier creates a massive, broad-floored, and steep-sided U-shaped valley. This happens because a glacier is not just a stream of water; it is a heavy, slow-moving solid mass of ice. While a river primarily erodes the valley floor (vertical erosion), a glacier’s immense weight allows it to erode both the floor and the valley walls with equal intensity, effectively "bulldozing" and grinding the pre-existing landscape PMF IAS, Chapter 17, p.231.

As the glacier moves through an old river valley, it smooths out the rough edges. A key feature left behind is the Hanging Valley. This occurs because the main glacier is much larger and deeper than the smaller tributary glaciers feeding into it. The main glacier carves a much deeper trough; once the ice melts, the tributary valley is left "hanging" at a significantly higher elevation than the main valley floor GC Leong, Chapter 6, p.62. These often become the sites of spectacular waterfalls as streams drop from the higher hanging valley into the deeper main trough.

The transformation of the landscape is so thorough that the ridges of land (spurs) that once jutted into the river valley are planed off by the passing ice. This creates truncated spurs, which look like triangular facets on the steep valley walls NCERT Class XI, Chapter 6, p.55. In some cases, the floor of these troughs is eroded below sea level. If the sea later floods these deep glacial valleys, they are known as fjords, a common feature along the coasts of Norway or New Zealand.

Feature	River Valley (Fluvial)	Glacial Trough (Glacial)
Shape	V-shaped	U-shaped
Floor	Narrow and tapered	Broad and flat
Sides	Sloping (Interlocking spurs)	Steep/Vertical (Truncated spurs)

Sources: FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.), Chapter 6: Landforms and their Evolution, p.48, 55; Physical Geography by PMF IAS, Chapter 17: Major Landforms and Cycle of Erosion, p.231; Certificate Physical and Human Geography, GC Leong, Chapter 6: Landforms of Glaciation, p.62

4. Glacial Depositional Landforms (intermediate)

When a glacier begins to melt or loses its momentum, it can no longer carry the massive load of rock, sand, and clay it has been hauling. This material, known as glacial till (unsorted debris) or outwash (sorted debris from meltwater), is deposited to create unique landforms. Unlike erosional landforms that are "carved out," depositional landforms are "built up."

The most prominent of these are Moraines. These are long ridges of glacial till. Depending on where the debris settles, we categorize them into four types. Terminal moraines are found at the very toe or end of the glacier, marking its furthest point of advance. Lateral moraines form along the sides of the glacial valley, while medial moraines form in the center when two tributary glaciers join and their lateral moraines merge FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.), Chapter 6, p.55-56. If the glacier retreats rapidly, it leaves behind an irregular sheet of debris across the valley floor called a ground moraine.

Other fascinating features include Drumlins and Eskers. Drumlins are smooth, oval-shaped hills that look like inverted spoons. They usually appear in clusters, creating a "basket of eggs" topography Certificate Physical and Human Geography, GC Leong, Landforms of Glaciation, p.64. Crucially, their orientation tells us the direction of ice flow—the steeper "stoss" end faces the direction the ice came from, while the tapered "tail" points downstream. Eskers, on the other hand, are winding, sinuous ridges of sand and gravel. They are formed by meltwater streams flowing in tunnels beneath the ice; when the ice melts, the sediment from the stream bed is left behind as a ridge FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.), Chapter 6, p.56.

Landform	Appearance	Origin
Drumlin	Oval, "inverted spoon" shape.	Reshaped till under moving ice.
Esker	Winding, sinuous ridge.	Sub-glacial meltwater stream deposits.
Moraine	Long ridges of unsorted debris.	Accumulation at the edges/front of ice.

Sources: FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.), Chapter 6: Landforms and their Evolution, p.55-56; Certificate Physical and Human Geography, GC Leong, Landforms of Glaciation, p.64

5. Fluvial vs. Glacial Landscapes (intermediate)

To understand the difference between fluvial (river-driven) and glacial (ice-driven) landscapes, we must first look at the physical state of the eroding agent. Running water is a liquid that follows the path of least resistance, primarily cutting downward into the earth. In contrast, a glacier is a massive, slow-moving solid block of ice that acts like a giant piece of sandpaper, scouring everything in its path—both the floor and the sides of its valley.

One of the most striking differences lies in the shape of the valleys they create. Rivers typically produce V-shaped valleys because their energy is concentrated on downcutting (vertical erosion) at the base of the stream Physical Geography by PMF IAS, Chapter 17, p.197. Glaciers, however, are so massive and powerful that they widen and deepen these pre-existing V-shaped valleys into broad U-shaped valleys or glacial troughs FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.), Chapter 6, p.55. Because glaciers often "remodel" existing river valleys, glacial topography is sometimes described as 'parasitic'—it lives off and modifies the work previously done by fluvial processes.

A unique erosional feature of glacial landscapes is the hanging valley. This occurs because the massive main glacier erodes its valley much more deeply than the smaller tributary glaciers feeding into it. When the ice melts, the floor of the tributary valley is left "hanging" high above the floor of the main valley, often creating spectacular waterfalls Physical Geography by PMF IAS, Chapter 17, p.231. Students often mistake these for depositional features, but they are purely erosional. On the depositional side, while rivers create alluvial fans at the base of mountains, glaciers (and their meltwater) create outwash plains—broad, flat areas covered with gravel, sand, and clay left behind as the ice retreats FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.), Chapter 6, p.56.

Feature	Fluvial (River)	Glacial (Ice)
Valley Shape	V-shaped (steep sides, narrow floor)	U-shaped (steep sides, broad flat floor)
Primary Action	Vertical downcutting and lateral erosion	Plucking, abrasion, and massive scouring
Key Erosional Form	Gorges, Potholes, Interlocking spurs	Cirques, Arêtes, Hanging Valleys
Depositional Form	Deltas, Alluvial fans, Floodplains	Moraines, Eskers, Outwash plains

Sources: FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.), Chapter 6: Landforms and their Evolution, p.54-56; Physical Geography by PMF IAS, Chapter 17: Major Landforms and Cycle of Erosion, p.197, 203, 231

6. Hanging Valleys and Parasitic Topography (exam-level)

To understand glacial landforms, we must first recognize that glaciers are often 'copycats'—they rarely create a landscape from scratch. This is why glacial topography is sometimes described as parasitic. Glaciers typically occupy pre-existing V-shaped river valleys. Because glacial ice is a massive, slow-moving solid, it erodes the valley uniformly, both vertically and horizontally, eventually reshaping the 'V' into a broad, steep-sided U-shaped glacial trough Physical Geography by PMF IAS, Major Landforms and Cycle of Erosion, p.231. It 'lives off' the fluvial (river) landscape, truncating interlocking spurs into triangular facets as it bulldozes through the path of least resistance.

A hanging valley is a classic erosional feature of this process. It occurs because of the difference in erosive power between a main glacier and its smaller tributaries. The main glacier, having much greater mass and weight, carves its valley significantly deeper than the smaller tributary glaciers can. When the ice eventually melts, the floor of the tributary valley is left 'hanging' high above the floor of the main trough. These are known as discordant tributaries because their levels do not match the main valley floor Certificate Physical and Human Geography, GC Leong, Landforms of Glaciation, p.62.

These landforms are not just geological curiosities; they have immense practical value. Because the stream from a hanging valley must 'jump' down to the main valley floor, it creates spectacular waterfalls. These sites are often ideal locations for generating hydro-electric power due to the natural head of water provided by the vertical drop Certificate Physical and Human Geography, GC Leong, Landforms of Glaciation, p.62.

Sources: Physical Geography by PMF IAS, Major Landforms and Cycle of Erosion, p.231; Certificate Physical and Human Geography, GC Leong, Landforms of Glaciation, p.62; NCERT Fundamentals of Physical Geography, Landforms and their Evolution, p.55

7. Solving the Original PYQ (exam-level)

This question is a classic application of the landform classification system you have just mastered. The core building blocks here involve distinguishing between erosional and depositional features. As you learned in NCERT Class XI Geography, glaciers are powerful agents of denudation that transform pre-existing landscapes. To solve this, you must evaluate each statement against the fundamental process: is the glacier removing material (erosion) or leaving it behind (deposition)?

Walking through the logic, Cirques (amphitheater-like basins) and U-shaped valleys (deepened troughs) are clearly the result of the glacier's massive weight scouring the earth, making Statements (A) and (B) factually accurate. The term parasitic nature in Statement (C) might seem unfamiliar, but as noted in Physical Geography by PMF IAS, it refers to how glacial topography modifies or "lives off" earlier fluvial (river-cut) landscapes. The reasoning breaks down at Statement (D); while hanging valleys are distinct glacial features, they are formed when a primary glacier erodes a deeper floor than its smaller tributary glacier. Because this is an erosional carving process, claiming it is depositional is false, making (D) the correct answer to this "not correct" query.

A common trap UPSC sets is the process-feature mismatch. Students often focus so much on what a landform looks like that they forget how it was made. You might see a hanging valley and think of the water it "deposits" as a waterfall, but in geomorphology, you must always look at the underlying structure. Remember: if the glacier carves out space, it is erosional; if it drops off debris (like moraines or eskers), it is depositional. Precision in these categories is your best defense against such traps.

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