---
title: "Geological agents and their geological work"
subject: "Engineering Geology I"
chapter: 6
key: "semester_3/engineering_geology_i:geological-agents-and-their-geological"
source: https://www.bctengineer.com/q/semester_3/engineering_geology_i/geological-agents-and-their-geological
site: BCT Engineering
---

# Geological agents and their geological work

Engineering Geology I · Chapter 6: Physical Geology

- Asked in: 2081 Bhadra, 2.5 marks; 2078 Bhadra, 1 marks; 2079 Bhadra, 2 marks; 2076 Chaitra, 1 marks; 2076 Asoj, 1.5 marks; 2075 Asoj, 2 marks; 2068 Baisakh, 2 marks (asked 7 times)
- Video: [Geological Agents](https://www.youtube.com/watch?v=cknyRm-LNpE) — Imran Syed
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/engineering_geology_i/geological-agents-and-their-geological
- Whole chapter: https://www.bctengineer.com/md/semester_3/engineering_geology_i/chapter-6

## Question

Mention the different geological agents and describe their geological work.

## Short answer

Geological agents include running water, groundwater, glaciers, wind, sea waves, gravity, volcanism, and organisms. They perform erosion, transportation, and deposition to shape landforms; running water is the dominant agent creating valleys, floodplains, and deltas.

## Answer

Geological agents are natural forces that wear down, move and rebuild the earth's surface. They are:

1. **Running water (rivers)**, the most important agent.
2. **Groundwater**, working below the surface.
3. **Glaciers (ice)**.
4. **Wind**.
5. **Sea waves, tides and currents**.
6. **Gravity** (mass movement), **volcanism** and **organisms** (including humans).

Each agent does three kinds of work: **erosion** (wearing away), **transportation** (carrying) and **deposition** (laying down), which together make a landform.

#### Geological work of the agents
| Agent | Erosion | Transport | Deposition |
|---|---|---|---|
| Running water | V-valleys, gorges, waterfalls | Solution, suspension, saltation, traction | Fans, floodplains, deltas |
| Groundwater | Caves, sinkholes, karst | Dissolved material | Stalactites, stalagmites, travertine |
| Glacier | Cirque, U-valley, arête | Ice carries blocks and till | Moraines, drumlins, eskers |
| Wind | Deflation, mushroom rocks, yardang | Suspension, saltation, surface creep | Dunes, loess |
| Sea waves | Cliffs, wave-cut platform, caves | Longshore drift | Beaches, bars, spits |
| Gravity | Landslides, rockfalls, creep | Downslope movement | Talus, colluvium |

- **Running water** is the most powerful agent: it makes valleys, carries sediments and builds the floodplain and delta.
- **Glaciers** move slowly but carry huge loads and make U-shaped valleys.
- **Wind** acts mainly in dry, sparsely vegetated areas.
- **Groundwater** works mainly by solution in limestone.
- **Sea** shapes the coast.

## Check yourself

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

1. Which is the most important geological agent?
   A. Running water
   B. Wind
   C. Glaciers
   D. Gravity
   Answer: A. Running water is the most powerful agent. (Key point: Most important agent)

2. What are the three kinds of work of agents?
   A. Folding, faulting and jointing
   B. Erosion, transportation and deposition
   C. Melting, cooling, crystallising
   D. Weathering, metamorphism, cementation
   Answer: B. Agents erode, carry and deposit. (Key point: Three works)

3. Which valley shape do glaciers make?
   A. V-shaped
   B. Flat plain
   C. U-shaped
   D. Delta
   Answer: C. Glaciers carve U-valleys; rivers carve V-valleys. (Key point: Glacier landform)

## Related in Engineering Geology I

- [Geological agents; geological cycle](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Ageological-agents-geological-cycle) — 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×

## Related in other subjects

- [Work and heat transfer; sign conventions](https://www.bctengineer.com/question.md?key=semester_2%2Ffundamental_of_thermodynamics_and_heat_transfer%3Awork-heat-sign-conventions) — Fundamental of Thermodynamics & Heat Transfer, chapter 2