---
title: "Constructive and destructive boundary; Himalaya formation"
subject: "Engineering Geology I"
chapter: 2
key: "semester_3/engineering_geology_i:constructive-and-destructive-boundary-himalaya"
source: https://www.bctengineer.com/q/semester_3/engineering_geology_i/constructive-and-destructive-boundary-himalaya
site: BCT Engineering
---

# Constructive and destructive boundary; Himalaya formation

Engineering Geology I · Chapter 2: Basic Reviews of the Earth

- Asked in: 2080 Bhadra, 3 marks
- Video: [The Himalayas: The Geological Story of Earth’s Greatest Mountain Collision | GEO GIRL](https://www.youtube.com/watch?v=3rwyZsnNgVg) — GEO GIRL and geosociety
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/engineering_geology_i/constructive-and-destructive-boundary-himalaya
- Whole chapter: https://www.bctengineer.com/md/semester_3/engineering_geology_i/chapter-2

## Question

Differentiate between constructive and destructive plate boundary. Write briefly on the formation of the Himalaya.

## Short answer

Constructive boundaries have plates moving apart with new crust creation; destructive boundaries converge, consuming or thickening crust. The Himalaya formed by India colliding with Eurasia, folding Tethys sediments along thrust faults; the range still rises at 4–5 cm per year.

## Answer

#### Constructive versus destructive boundary

| Basis | Constructive (divergent) | Destructive (convergent) |
|---|---|---|
| Movement | Plates move apart | Plates move together |
| Crust | New crust created | Crust consumed or thickened |
| Features | Mid-ocean ridge, rift valley | Trench, volcanoes, fold mountains |
| Earthquakes | Shallow | Shallow to deep |
| Example | Mid-Atlantic Ridge | Himalaya, Andes |

#### Formation of the Himalaya
The Indian plate separated from Gondwanaland and moved north across the Tethys Sea. Tethys oceanic crust was subducted under Eurasia. About 50 million years ago India collided with Eurasia. Because both are light continental crust, neither sank, so the thick Tethys sediments were folded, thrust and uplifted, forming the Himalaya along thrusts such as the MCT, MBT and MFT. The movement continues at about 4-5 cm per year, so the range still rises and has earthquakes.

## Check yourself

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

1. Constructive boundary is also:
   A. Convergent
   B. Divergent
   C. Transform
   D. Collisional
   Answer: B. New crust created. (Key point: Constructive)

2. Himalaya formed ~50 Ma when:
   A. India separated from Africa
   B. Tethys opened
   C. India collided with Eurasia
   D. Plates diverged
   Answer: C. Collision. (Key point: Himalaya cause)

3. Neither plate sank because:
   A. Both are dense
   B. Tethys was cold
   C. There was no sediment
   D. Both are light continental crust
   Answer: D. Sediments folded and thrust. (Key point: Why uplift)

## Related in Engineering Geology I

- [Himalaya formation and plate tectonic evidence](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Ahimalaya-formation-and-plate-tectonic) — Engineering Geology I, chapter 2
- [Plate boundary and mountain formation](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Aplate-boundary-and-mountain-formation) — Engineering Geology I, chapter 2
- [Formation and evolution of the Himalaya](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Aformation-and-evolution-of-the) — Engineering Geology I, chapter 2, asked 5×
- [Transform versus divergent plate boundary](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Atransform-versus-divergent-plate-boundary) — Engineering Geology I, chapter 2
- [Convergent versus divergent plate boundary](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Aconvergent-versus-divergent-plate-boundary) — Engineering Geology I, chapter 2, asked 3×

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- [Conditions for constructive and destructive interference](https://www.bctengineer.com/question.md?key=semester_1%2Fengineering_physics%3Aconstructive-destructive-path-difference) — Engineering Physics, chapter 4
- [Hydrodynamic and thermal boundary layers](https://www.bctengineer.com/question.md?key=semester_5%2Fheat_transfer%3Ahydrodynamic-thermal-boundary-layer) — Heat Transfer, chapter 3
- [Boundary fill vs flood fill](https://www.bctengineer.com/question.md?key=semester_5%2Fcomputer_graphics%3Aboundary-fill-vs-flood-fill) — Computer Graphics, chapter 2
- [Essential and natural boundary conditions](https://www.bctengineer.com/question.md?key=semester_8%2Ffinite_element_method%3Aessential-natural-boundary-conditions) — Finite Element Method, chapter 2