A glacier is a massive ice mass that travels slowly across land. Glaciers are commonly referred to as ice rivers. Glacial depositional landforms such as Outwash Plain, Eskers, Kame Terraces, Drumlin, Kettle Holes, and Moraine resulting from the accumulation of sediment transported by these moving ice masses, dot landscapes from the poles to temperate zones. Though a glacier is not liquid, it moves over time due to the constant pressure exerted by the snow that has collected above it which is responsible for the creation of various landforms. In this article, we will discuss various Glacial Depositional Landforms that will be helpful for UPSC IAS exam.

What is Glacial Deposition?

• The settling of sediments left behind by a moving glacier is known as a glacial deposition.
• Glaciers gather up sediments and rocks as they move across the earth.
• Glacial till is a combination of unsorted sediment deposits transported by the glacier.
• Moraines are piles of till deposited at the borders of former glaciers.

Glacial Depositional Landforms

Moraines

• Moraines are made up of granite fragments fractured by frost, lodged in glaciers, and carried down the valley.
• The one that falls on the glacier's sides generates lateral moraines.
• The interior lateral moraines of two glaciers converge to produce a medial moraine when they meet.
• When the glacier melts, rock fragments carried beneath the frozen ice are released and scattered across the valley floor as ground moraine.
• When the glacier reaches the valley's foot, it melts, and the mound of transported debris left behind at the snout is known as terminal moraine or end moraine.

Drumlins

• Drumlins are oval-shaped hills produced beneath a glacier or ice sheet and are oriented in the direction of ice flow, mostly made up of glacial drift.
• They are common in historically glaciated locations, with populations particularly high in Canada, Ireland, Sweden, and Finland.
• They are low hills that are up to 1.5 km long and 60 mm in height, with a steeper onset side and a flatter leeward side.
• This topography is usually referred to as a basket of eggs since they are positioned diagonally.
• The topography of drumlins, which are usually found in clusters, is known as ‘basket of egg topography.’
• Drumlin fields are regions where there are a lot of drumlins.

Eskers

• Eskers are sinuous ridges formed by meltwater currents depositing glacial material, primarily sands and gravel, in glacial tunnels.
• Subglacial meltwater streams were once channeled through glacial tunnels.
• Their length can sometimes surpass 100 kilometers and their orientation is normally parallel to the path of glacier movement.

Outwash plains

• When a glacier melts at its lowest point, it leaves behind a stratified deposition material consisting of rock debris, clay, sand, gravel, and other materials.
• Till plain or an outwash plain refers to this stratified surface.

Kettle Lake

• A kettle lake (also known as a kettle, kettle hole, or pothole) is a dip or hole produced by retreating glaciers or draining floodwaters in an outwash plain.
• The kettles are formed by dead ice blocks left behind by retreating glaciers, which become encircled by sediment deposited by meltwater streams as friction increases.

Kames

• A kame, or knob, is a glacial landform that consists of an unevenly shaped hill or mound made up of sand, gravel, and till that collects in a depression on a retreating glacier and is subsequently deposited on the land surface when the glacier melts further.
• Kame terraces are layered deposits of meltwater streams running between the ice and the surrounding valley slope that are commonly observed along the side of a glacier valley.

Types of Glaciers

Continental Glaciers

• Continental glaciers are continuous masses of ice that are much larger than alpine glaciers.
• There are no mountains or other features that surround these glaciers.
• As a result, they tend to spread out and cover everything in their path.
• When ice sheets spread out from the center, they cover entire valleys, plains, and even mountain ranges with snow.
• By definition, they have areas larger than 50,000 km square.
• Some examples of continental glaciers are Antarctica, Iceland, Greenland, etc.

Ice Caps

• The ice caps are the snow and ice covers on mountain ranges that give rise to valley or mountain glaciers.
• These massive glacial formations can feed a variety of different glaciers that branch out from their center.
• They can be found at lower elevations as well.
• The area of the ice caps is less than 50,000 km square.

Piedmont Glaciers

• At the foot of the mountains, the piedmont glaciers form a continuous sheet of ice.
• A mass of ice that has moved downslope towards low-lying plains is referred to as a Piedmont Glacier.
• It spreads out throughout the landscape, forming broad lobes of solid ice.
• One of the most well-known instances of this type of glacier is Alaska's Malaspina Glacier.

Valley Glaciers

• A valley glacier is a glacier that fills a valley. Valley glaciers, also known as Alpine Glaciers, are located in valleys formed by high mountains such as the Himalayas in India.
• Because of their long and narrow, ribbon-like shape, these glaciers are generally simple to spot.
• The majority of valley glaciers originate in mountain glaciers and extend to gorges, basins, and, of course, valleys.

Significance of Glaciers

• Drinking water is provided by glaciers.
• Crops are irrigated by glaciers.
• Glaciers aid in the generation of hydroelectric power.
• They help in shaping the landforms.

Conclusion

Glaciers are incredibly powerful agents of erosion. Glaciers begin to form where more snow accumulates each year than they melt. Immediately after it falls, the snow either compresses or becomes denser and begins to crowd. With its great erosion power, ice movement in the form of glaciers has changed our mountainous land surfaces. The eroded material is later deposited in moraines, stratified drift, outwash plains, and drumlins as enormous glacial erratics.

FAQs

MCQs

1. What are outwash plains primarily formed from?

A) Wind erosion
B) River deposition
C) Glacial meltwater deposition
D) Coastal processes

2. Eskers are formed by which of the following processes?

A) Wind action
B) Subglacial meltwater deposition
C) Glacial erosion
D) Volcanic activity

3. Which feature is characterized by irregularly shaped mounds formed from sediment deposition?

A) Drumlins
B) Kames
C) Kettle holes
D) Outwash plains

4. Drumlins provide insight into what aspect of glacial geology?

A) Glacial retreat
B) Ice melt rates
C) Glacier flow patterns
D) Erosion processes

5. What is the primary cause of kettle holes formation?

A) River erosion
B) Melting of buried ice blocks
C) Wind action
D) Volcanic activity

GS Mains Questions and Model Answers

Q1: Explain the formation processes and significance of outwash plains and eskers in glacial landscapes.

Answer: Outwash plains and eskers are significant features in glacial landscapes formed by different processes of sediment deposition. Outwash plains are created by meltwater streams flowing from glaciers, which transport and deposit sediments in broad, flat areas. This deposition leads to fertile soils that can support agriculture and biodiversity. Eskers, on the other hand, are formed when sediments are deposited in subglacial tunnels. The formation of eskers showcases the dynamic processes beneath glaciers and provides insights into historical glacial movements. Both features are critical for understanding past climatic conditions and the evolution of the landscape, serving as indicators of the extent and behavior of ancient glaciers.

Q2: Discuss the ecological importance of kames and kettle holes in glacial environments.

Answer: Kames and kettle holes play vital ecological roles in glacial environments. Kames, formed from the accumulation of sediments, provide diverse habitats for flora and fauna, contributing to local biodiversity. Their varying elevations and soil types can support different plant communities, enhancing ecosystem resilience. Kettle holes, which may fill with water, create unique wetland habitats that are crucial for aquatic biodiversity, serving as breeding grounds for amphibians and habitats for migratory birds. Together, these landforms contribute to the ecological diversity of glaciated regions and can influence local hydrology, impacting water quality and availability for surrounding ecosystems.

Q3: Evaluate the impact of glacial landforms on human activities and settlement patterns.

Answer: Glacial landforms such as outwash plains, drumlins, and eskers significantly influence human activities and settlement patterns. Outwash plains are often fertile and suitable for agriculture, attracting farming communities and facilitating crop production. The flat terrain and rich soils make them ideal for settlement. Drumlins can affect local drainage patterns, impacting agriculture and infrastructure development. Eskers can serve as natural routes for transportation due to their elevated positions. However, the presence of kettle holes can pose challenges, such as flood risks or the need for special drainage considerations. Overall, understanding these glacial landforms is essential for effective land use planning, agricultural development, and sustainable management of natural resources in glaciated regions.

Previous Year Questions on Glacial Depositional Landforms

1. UPSC CSE Prelims 2021:

Question: What type of landform is created by the deposition of sediments in subglacial tunnels?

A) Kettle hole
B) Drumlin
C) Esker
D) Outwash plain

Answer: (C)

Explanation: An esker is formed by the deposition of sediments in subglacial tunnels beneath glaciers.

2. UPSC CSE Mains 2019 (GS Paper 1):

Question: "Analyze the significance of glacial depositional landforms in shaping the landscape and their implications for human activities." Discuss their role in ecology and settlement patterns.

Answer: Glacial depositional landforms, such as eskers, kames, and kettle holes, significantly shape the landscape by influencing topography and hydrology. These landforms create fertile soils and diverse habitats, promoting ecological richness. Their characteristics impact human activities by determining agricultural potential and settlement patterns. For instance, outwash plains are favored for agriculture due to their fertility, while kettle holes provide critical habitats for wildlife. Understanding these interactions helps inform land-use planning, resource management, and the sustainability of communities in glaciated regions.