A plate process links to a landform through a short chain: the plates move, something happens to the crust, and a feature appears at the surface. Name each link in your answer.
This lesson belongs to plate movement and tectonic processes. It assumes you can already tell the boundaries apart in diagrams.
Which process makes which landform?
| Boundary | Process | Landform |
|---|---|---|
| Convergent, ocean and continent | Dense ocean plate is subducted | Deep ocean trench, volcanic mountains |
| Convergent, continent and continent | Crust is squeezed and folded | Fold mountains |
| Divergent, under the sea | Magma rises and adds new crust | Mid-ocean ridge |
| Divergent, on land | Crust is stretched, blocks drop | Rift valley |
| Transform | Plates grind sideways | Fault, offset features |
Worked example: an original island chain
An original diagram shows a chain of volcanic islands. A deep trench runs parallel to the chain, on the side facing a wide ocean. An arrow on the ocean plate points towards the islands.
Chain of reasoning:
- The arrow on the ocean plate points towards the islands, so the plates converge.
- The ocean plate is thin and dense, so it is subducted beneath the plate carrying the islands.
- Where the plate bends down, a trench forms. As it sinks, it melts, and magma rises to build the volcanic islands.
Each link uses a clue from the diagram: the arrow, the trench and the volcanoes. The trench and the volcano line sit parallel because both follow the edge where the plate sinks.
The mistake: naming the landform without the process
A common slip is to write “a trench forms at a convergent boundary” and stop. The fact is correct, but the answer skips the process, and the marks are for the link.
A second slip is to treat every mountain range the same. The table shows two different convergent cases: a volcanic mountain line comes from subduction, and a fold mountain belt comes from a collision of continents.
| Case | Incomplete | Complete |
|---|---|---|
| Trench | “Convergent boundary” | “Plates converge, the ocean plate sinks, and a trench forms” |
| Fold mountains | “Plates collide” | “Two continents collide, neither sinks, so the crust is folded upward” |
Check yourself
An original diagram shows a long underwater ridge with arrows pointing away from its centre, and newly formed rock on either side. Name the boundary and the landform, and write a three-link explanation.
Answer
The boundary is divergent, and the landform is a mid-ocean ridge.
Chain: the arrows point away from the centre, so the plates move apart. Magma rises through the gap and cools. The new rock builds the ridge and adds crust on both sides.
What to study next
Move on to explaining earthquake patterns from supplied location data, which uses the same subduction idea on a table of depths. Or test yourself on the tectonic practice set.
If you want a teacher to check your reasoning chains, see online one-to-one Geography tuition.