Unit 3 - Essays - Plate Tectonics SIMPLE ENGLISH UPDATED

Question 1

“With the aid of examples, assess the extent to which subduction is involved in the formation of tectonic landforms.”

Answer 1

Main Body Paragraph 1: Subduction Helps Create Volcanoes
Main Idea: Subduction is very important for making volcanoes at destructive plate boundaries.

How does it work?
An oceanic plate (which is heavy) moves under another plate.
The plate melts because of friction and heat.
The melted rock (magma) rises to the surface and forms a volcano.
Examples:
The Andes Mountains (South America):
The Nazca Plate moves under the South American Plate at 7–9 cm per year.
This has created big volcanoes like Cotopaxi in Ecuador.
The Pacific “Ring of Fire”:
This is an area with 75% of the world’s volcanoes.
Includes volcanoes like Mount St. Helens (USA) and Mount Fuji (Japan).
How long does this take?
Subduction happens over millions of years.
Volcanoes grow bigger as more magma comes up.
Why does this matter?
Shows that subduction is very important for creating volcanoes.

Main Body Paragraph 2: Subduction Creates Deep Ocean Trenches
Main Idea: Subduction makes deep valleys in the ocean called trenches.

How does it work?
When an oceanic plate moves under another plate, it pulls the ocean floor down.
This makes a deep trench in the sea.
Examples:
Mariana Trench (Pacific Ocean):
It is the deepest place on Earth at 10,994 meters.
It was made when the Pacific Plate moved under the Mariana Plate.
Peru-Chile Trench:
It is 5,900 km long, off the coast of South America.
Formed because the Nazca Plate is sinking under the South American Plate.
How long does this take?
Trenches take millions of years to form and keep getting deeper.
Why does this matter?
This proves subduction is very important for making ocean trenches.

Main Body Paragraph 3: Mid-Ocean Ridges Are NOT Made by Subduction
Main Idea: Mid-ocean ridges form when plates move apart, not when one moves under another.

How does it work?
Two plates move away from each other.
Magma rises from the mantle and makes new ocean floor.
Examples:
Mid-Atlantic Ridge:
It is 16,000 km long and runs through the Atlantic Ocean.
The North American and Eurasian plates move apart at 2 cm per year.
East Pacific Rise:
Plates move apart very fast (6–16 cm per year).
New ocean crust forms instead of subduction happening.
How long does this take?
This happens over millions of years, slowly making huge underwater mountain chains.
Why does this matter?
It proves that not all landforms need subduction.

Main Body Paragraph 4: Rift Valleys Are NOT Made by Subduction
Main Idea: Rift valleys are formed when plates pull apart, not when one moves under another.

How does it work?
The land stretches and breaks, making large cracks in the Earth’s surface.
The middle part of the land sinks down, forming a valley.
Examples:
East African Rift Valley:
6,400 km long, stretching from Syria to Mozambique.
The African Plate is splitting into two smaller plates (Nubian and Somali) at 0.5 cm per year.
This is why we see deep valleys and volcanoes like Mount Kilimanjaro.
Baikal Rift Valley (Russia):
Deepest rift valley in the world at 1,642 meters deep.
It was formed by stretching, not subduction.
How long does this take?
Rift valleys take millions of years to fully form.
Why does this matter?
Rift valleys show that subduction is not needed for all landforms.

Conclusion
Subduction is very important for volcanoes and ocean trenches.
But some landforms do not need subduction (mid-ocean ridges, rift valleys).
Final Judgement:
Subduction is crucial for some landforms, but not all.
Different landforms are made in different ways, and subduction is only one part of Earth’s tectonic processes.