---
title: "Erosional and depositional landforms of glaciers"
subject: "Engineering Geology I"
chapter: 6
key: "semester_3/engineering_geology_i:erosional-and-depositional-landforms-of"
source: https://www.bctengineer.com/q/semester_3/engineering_geology_i/erosional-and-depositional-landforms-of
site: BCT Engineering
---

# Erosional and depositional landforms of glaciers

Engineering Geology I · Chapter 6: Physical Geology

- Asked in: 2080 Bhadra, 4 marks; 2080 Baisakh, 2 marks; 2075 Asoj, 4 marks (asked 3 times)
- Video: [Glacial Landforms](https://www.youtube.com/watch?v=OvRXWbTZ8YY) — GeoScience Videos
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/engineering_geology_i/erosional-and-depositional-landforms-of
- Whole chapter: https://www.bctengineer.com/md/semester_3/engineering_geology_i/chapter-6

## Question

Define glacier. Describe the erosional and depositional landforms formed by glaciers.

## Short answer

A glacier is a moving mass of ice. Erosional landforms include cirques, arêtes, horns, U-shaped valleys, hanging valleys, and striations. Depositional landforms comprise various moraines, drumlins, eskers, kames, and erratics.

## Answer

A **glacier** is a large mass of ice formed by compaction and recrystallisation of snow, which moves slowly downslope under its own weight. Types: valley (alpine) glaciers, as in the Nepal Himalaya, and continental ice sheets.

#### Erosional landforms
Glaciers erode by **plucking** (ice freezes to the rock and pulls out blocks) and **abrasion** (rock fragments in the ice scrape the bed).

- **Cirque (corrie):** armchair-shaped hollow at the head of a glacier, made by plucking and abrasion; a lake in it is a *tarn*.
- **Arête:** knife-edge ridge between two cirques.
- **Horn (pyramidal peak):** sharp peak left when cirques cut back on all sides, e.g. Matterhorn.
- **U-shaped valley (glacial trough):** the glacier widens and deepens a river valley.
- **Hanging valley:** side valley left high above the main trough; it often ends in a waterfall.
- **Fjord:** glacial trough drowned by the sea.
- **Roche moutonnée, striations and grooves:** smoothed and scratched bedrock surfaces.
- **Rock basins and tarns.**

#### Depositional landforms
Material carried by ice is called **till** (unsorted, unstratified clay, sand, pebbles and boulders). Features:

- **Moraines:** lateral, medial, terminal (end) and ground moraines.
- **Erratics:** large boulders carried far from their source rock.
- **Drumlins:** smooth, elongated hills of till, shaped like an inverted spoon.
- **Eskers:** long, winding ridges of sand and gravel left by streams under the ice.
- **Kames and outwash plains:** mounds and flat areas of sorted sand and gravel built by meltwater.
- **Kettle holes:** depressions left where buried ice blocks melted.

```text
  Section of a glaciated valley
  \   /\        /\   arete   /
   \_/  \______/  \_ cirque /
        U-shaped valley floor
```

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. What is a glacier?
   A. A river of meltwater
   B. A snowfield that does not move
   C. Mass of ice formed by compaction and recrystallisation of snow that moves slowly downslope
   D. Frozen sea water
   Answer: C. It moves under its own weight. (Key point: Glacier)

2. Which two processes do glaciers use to erode?
   A. Hydraulic action and attrition
   B. Deflation and saltation
   C. Solution and carbonation
   D. Plucking and abrasion
   Answer: D. Plucking pulls out blocks; abrasion scrapes the bed. (Key point: Erosion mechanisms)

3. What is an arete?
   A. Knife-edge ridge between two cirques
   B. Armchair hollow at the glacier head
   C. Side valley high above the trough
   D. Glacial trough drowned by sea
   Answer: A. Cirques cutting back to back leave a sharp ridge. (Key point: Cirque and arete)

4. What is till?
   A. Sorted sand from meltwater
   B. Unsorted, unstratified material deposited by ice
   C. Dissolved salts
   D. Wind-blown silt
   Answer: B. Meltwater deposits are sorted; till is not. (Key point: Till)

5. What is an esker?
   A. Smooth hill shaped like an inverted spoon
   B. Depression from melted ice block
   C. Long winding ridge of sand and gravel left by streams under the ice
   D. Large boulder carried far
   Answer: C. Drumlins are spoon-shaped till hills; kettle holes are depressions. (Key point: Eskers)

## Related in Engineering Geology I

- [Erosional and depositional features of river and glacier](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Aerosional-and-depositional-features-of) — Engineering Geology I, chapter 6, asked 2×
- [Erosional features of glacier and underground water](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Aerosional-features-of-glacier-and) — Engineering Geology I, chapter 6
- [Geological work of wind and its landforms](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Ageological-work-of-wind-and) — Engineering Geology I, chapter 6, asked 6×
- [Geological work of running water and its landforms](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Ageological-work-of-running-water) — Engineering Geology I, chapter 6, asked 5×