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

# Geological cycle

Engineering Geology I · Chapter 6: Physical Geology

- Asked in: 2078 Bhadra, 1 marks; 2074 Chaitra, 2 marks (asked 2 times)
- Video: [What is Geological cycle: Geologic Cycle](https://www.youtube.com/watch?v=2Mjo8MT4whk) — Geotourism and Modern Geotechniques
- 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-cycle
- Whole chapter: https://www.bctengineer.com/md/semester_3/engineering_geology_i/chapter-6

## Question

What is the geological cycle?

## Short answer

The geological cycle is the continuous process of rock formation, destruction, and re-formation through igneous, sedimentary, and metamorphic stages, linking tectonic uplift, weathering, erosion, and melting.

## Answer

The **geological cycle** is the continuous, slow, cyclic process by which the rocks of the earth's crust are formed, destroyed and re-formed into other kinds of rock. It has no start or end. It links the rock cycle, the hydrological cycle and plate tectonics.

```text
 Magma --cooling--> Igneous rock
   ^                    |
 melting         weathering, erosion
   |                    v
 Metamorphic <--heat,-- Sediments
 rock         pressure     |
   ^                       |compaction,
   |                       v cementation
   +------heat,--------Sedimentary rock
        pressure
```

- Magma cools to **igneous rock**.
- Weathering, erosion, transport and deposition give **sediments**, which become **sedimentary rock** by lithification.
- Heat and pressure change any rock into **metamorphic rock**.
- Deep burial and melting return the rock to **magma**.

Uplift brings deep rocks back to the surface. Engineers use this idea to understand why different rock types occur at a site.

## Check yourself

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

1. What is the geological cycle?
   A. A one-time sequence ending in sedimentary rock
   B. The movement of water only
   C. The daily temperature cycle
   D. Continuous cyclic process by which crustal rocks are formed, destroyed and re-formed
   Answer: D. It has no start or end. (Key point: Meaning)

2. How do sediments become sedimentary rock?
   A. Compaction and cementation (lithification)
   B. Cooling
   C. Melting
   D. Heat and pressure
   Answer: A. Heat and pressure would give metamorphic rock. (Key point: Lithification)

3. How does rock return to magma?
   A. Weathering
   B. Deep burial and melting
   C. Erosion
   D. Deposition
   Answer: B. Melting closes the cycle. (Key point: Return to magma)

4. What forms metamorphic rock?
   A. Cooling of magma
   B. Cementation of sediments
   C. Heat and pressure acting on any rock
   D. Evaporation
   Answer: C. Any rock can be metamorphosed. (Key point: Metamorphic)

## 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