Good Learning Co.
SavannahYear 8
← Geography
GeographyRestless Earth: plates, earthquakes and volcanoes25 min★★★ difficulty

Plate margins: destructive, constructive, conservative and collision

Four margins, four stories. Get these straight and you can predict the hazard at almost any point on a tectonic map without being told the answer.

Part of your national curriculum
  • Human and physical geography: Understand how geographical processes interact to create distinctive human and physical landscapes that change over time
  • Human and physical geography: Understand tectonic processes and hazards, including earthquakes and volcanic activity

Lesson overview

What you'll learn in this lesson

Explain the processes and landforms at each type of plate margin.

Key learning points

  • • Destructive margins
  • • Constructive margins
  • • Conservative margins
  • • Collision margins

This lesson at a glance

  • 25 minutes
  • 16 parts to scroll through
  • 4 quick checks
  • Marked quiz at the end
  • Gentle pace: short sittings with pauses

Words to know

processeslandformsmargindestructivemargins

Scroll down — the lesson carries on below

Part 1 of 16 · Discover6%
1

Watch & discover

Part 1 of 16

Watch first

Plate margins: destructive, constructive, conservative and collision

An English teaching video on this topic from Equatoro. Watch it, then scroll down for the lesson.

In a nutshell

Explain the processes and landforms at each type of plate margin.

2

Learning cycle

Part 2 of 16

Learning cycle 1 of 2

Part 1 · Destructive margins

A short piece of teaching, then a check to make sure it has landed.

3

Explore the idea

Part 3 of 16

Learn

Destructive margins

An oceanic plate meets a continental plate and is forced down into the mantle at a subduction zone. Friction and water released from the sinking slab melt rock above, producing sticky, gas-rich magma. Result: deep ocean trenches, violent composite volcanoes and the deepest, most powerful earthquakes on Earth, as at the west coast of South America where the Nazca plate dives under the South American plate to raise the Andes.

4

Explore the idea

Part 4 of 16

Learn

Constructive margins

Two plates separate and mantle rock melts as pressure falls, filling the gap with runny basaltic lava. Eruptions are frequent but usually gentle, and earthquakes are shallow and small. Iceland sits on the mid-Atlantic ridge and gains land, geothermal power and regular fissure eruptions from exactly this process.

5

Quick check

Part 5 of 16

Quick check

Which margin creates ocean trenches and composite volcanoes?

6

Quick check

Part 6 of 16

Quick check

Why are there no volcanoes at a conservative margin?

7

Reset break

Part 7 of 16

Pause

That's sitting 1 of 2 done

Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.

Stop here for now
8

Learning cycle

Part 8 of 16

Learning cycle 2 of 2

Part 2 · Conservative margins

A short piece of teaching, then a check to make sure it has landed.

9

Explore the idea

Part 9 of 16

Learn

Conservative margins

Plates slide past one another, sometimes in the same direction at different speeds. No crust is created or destroyed, so there are no volcanoes, but friction locks the plates until stress overcomes it and they jolt. That jolt is the earthquake. The San Andreas Fault in California is the standard example, and the shallow depth of these quakes makes them dangerous despite moderate magnitudes.

10

Explore the idea

Part 10 of 16

Learn

Collision margins

Two continental plates meet and neither can sink because both are low density. The crust crumples and thickens upwards into fold mountains. The Indian plate is still pushing north into Eurasia, which is why the Himalayas continue to rise and why Nepal suffers large, shallow earthquakes with no volcanic activity.

11

Quick check

Part 11 of 16

Quick check

Which landform dominates a collision margin?

12

Quick check

Part 12 of 16

Quick check

Iceland gains new land each year because it lies on a

13

Explore the idea

Part 13 of 16

Worked example

Worked answer: explain why volcanoes at destructive margins erupt more violently than those at constructive margins (4 marks)

At a destructive margin the melting slab produces magma that is rich in silica and dissolved gas, so it is thick and sticky (1). Sticky magma traps gas until pressure builds high enough to blast material out explosively as ash and pyroclastic flows (1). At a constructive margin the magma comes straight from the mantle, is low in silica and runny (1), so gas escapes easily and lava flows out steadily rather than exploding (1).

14

Challenge round

Part 14 of 16

Game · Sort it

Which of these are true?

Drag each card into the right column. Tap a card first if dragging is fiddly.

True

Not true

15

Mastery quiz

Part 15 of 16

Marked quiz

End of lesson quiz: Plate margins: destructive, constructive, conservative and collision

4 questions, marked with the reasoning shown. No timer.

  1. 1. Which margin creates ocean trenches and composite volcanoes?

  2. 2. Why are there no volcanoes at a conservative margin?

  3. 3. Which landform dominates a collision margin?

  4. 4. Iceland gains new land each year because it lies on a

16

Lesson round-up

Part 16 of 16

Lesson round-up

Ready when you are

Quiz score

Not sat

Games

Not played

Points this lesson

0

Best run

0 in a row

Luna: 0 out of 4 on the practice checks. Only if you feel up to it — one more?

Ask Luna

Do the work

Your written work for this lesson

This is the part you'd do in your book at school. Pick the pieces below, write here or on paper, and photograph anything you draw or work out.

Case study

Flooding on the River Calder

The town of Harbrook sits where a steep valley opens onto a flat floodplain. In December 2015, 120 mm of rain fell in 36 hours onto ground that was already saturated. The river rose 2.4 m in five hours, and 380 homes and 54 businesses flooded. Two roads and the railway closed for eleven days.

Geographers pointed to physical causes — steep slopes, impermeable rock, heavy rainfall — and human causes: moorland drained upstream, new housing built on the floodplain, and drains designed for smaller storms.

Since then the town has planted 40 hectares of woodland upstream, built leaky dams in small streams, and raised flood walls to 1.8 m. In the storm of 2020 the peak river level was 0.3 m lower and 40 homes flooded, not 380.

Written for Good Learning Co.

Reading questions

  1. List two physical and two human causes of the 2015 flood.
  2. Explain how planting woodland upstream lowers the river's peak level.
  3. Using the figures, judge how successful the scheme has been. Quote data in your answer.

  • Case study notes

    Writing

    Write the place, the facts and the figures from this lesson so you can revise them later.

    Half a page

  • Explain answer

    Writing

    Answer in full sentences, giving causes and effects. Use one figure or place name as evidence.

    8–10 sentences

  • Map or sketch

    Diagram

    Draw the map, cross-section or field sketch with a key, title and labels, then photograph it.

    1 map with a key

  • Data work

    Working out

    Plot your figures as a graph on paper and write one sentence about the pattern.

    1 graph + 1 sentence

Saved as you type.

Part 1 of 16 · Watch & discover

How this is going

  • Not looked at yet

    Understand how geographical processes interact to create distinctive human and physical landscapes that change over time

  • Not looked at yet

    Understand tectonic processes and hazards, including earthquakes and volcanic activity

Good Learning Co. — personalised UK curriculum learning, built around what each learner loves.