---
title: "Cataclastic and plutonic metamorphism"
subject: "Civil Engineering Materials"
chapter: 2
key: "semester_3/civil_engineering_materials:cataclastic-plutonic-metamorphism"
source: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/cataclastic-plutonic-metamorphism
site: BCT Engineering
---

# Cataclastic and plutonic metamorphism

Civil Engineering Materials · Chapter 2: Building Stones

- Asked in: 2073 Shrawan, 2 marks
- Video: [Sedimentology lecture 4 - Rocks of Mechanical Origin, English](https://www.youtube.com/watch?v=h78PrTKCa6E) — Success Guru
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/cataclastic-plutonic-metamorphism
- Whole chapter: https://www.bctengineer.com/md/semester_3/civil_engineering_materials/chapter-2

## Question

Define cataclastic metamorphism and plutonic metamorphism of rock formation.

## Short answer

Cataclastic metamorphism is rock change by intense mechanical stress and crushing with little heat, forming mylonite. Plutonic metamorphism is recrystallisation at great depths under high uniform temperature and pressure, forming gneiss from granite.

## Answer

#### Cataclastic metamorphism
**Cataclastic (dynamic) metamorphism** is the change of a rock into a new form by intense mechanical stress and crushing, such as during faulting and mountain building (folding), without much heat. The minerals are broken and ground down, with little recrystallisation (examples: mylonite, fault breccia).

#### Plutonic metamorphism
**Plutonic metamorphism** is the change of rocks at great depths in the crust under very high temperature and very high, uniform (all-round) pressure caused by deep burial. The rock texture and minerals are recrystallised (example: gneiss from granite; granulite).

## Check yourself

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

1. Cataclastic metamorphism is caused mainly by:
   A. Very high temperature at depth
   B. Deposition of sediments
   C. Intense mechanical stress and crushing, without much heat
   D. Cooling of lava
   Answer: C. It occurs during faulting and folding by crushing. (Key point: Cataclastic cause)

2. Plutonic metamorphism occurs:
   A. At the surface by weathering
   B. By cooling of sea water
   C. Only by earthquakes
   D. At great depth under high temperature and pressure
   Answer: D. Deep burial and hot magma recrystallise rocks. (Key point: Plutonic cause)

3. Which is an example of plutonic metamorphism?
   A. Gneiss from granite
   B. Mylonite
   C. Fault breccia
   D. Sandstone from sand
   Answer: A. Gneiss forms from granite; mylonite and fault breccia are cataclastic. (Key point: Examples)

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