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
- 20 parts to scroll through
- 4 quick checks
- Marked quiz at the end
- Gentle pace: short sittings with pauses
Words to know
Scroll down — the lesson carries on below
Watch & discover
Part 1 of 20
Visual introductionPicture this
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.
In a nutshell
Explain the processes and landforms at each type of plate margin.
Learning cycle
Part 2 of 20
Learning cycle 1 of 2
Part 1 · Destructive margins
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 3 of 20
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.
Reset break
Part 4 of 20
Pause
That's sitting 1 of 5 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.
Explore the idea
Part 5 of 20
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.
Quick check
Part 6 of 20
Quick check
Part 7 of 20
Reset break
Part 8 of 20
Pause
That's sitting 2 of 5 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.
Learning cycle
Part 9 of 20
Learning cycle 2 of 2
Part 2 · Conservative margins
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 10 of 20
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.
Explore the idea
Part 11 of 20
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.
Reset break
Part 12 of 20
Pause
That's sitting 3 of 5 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.
Quick check
Part 13 of 20
Quick check
Part 14 of 20
Explore the idea
Part 15 of 20
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).
Reset break
Part 16 of 20
Pause
That's sitting 4 of 5 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.
Challenge round
Part 17 of 20
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
Challenge round
Part 18 of 20
Game · Recall cards
Abrasion is…
Card 1 of 4
Mastery quiz
Part 19 of 20
Marked quiz
End of lesson quiz: Plate margins: destructive, constructive, conservative and collision
4 questions, marked with the reasoning shown. No timer.
1. Abrasion is…
2. Deposition happens when…
3. Attrition affects…
4. Managed retreat is…
Lesson round-up
Part 20 of 20
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 LunaPart 1 of 20 · 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