How Mountains are Formed (3.2) Flashcards
Crust
(Layers of the Earth’s Surface)
- Crust is broken into large slabs, called plates
- Outer layer of the Earth’s surface
- The movement of these tectonic plates creates mountains and valleys
Mantle
(Layers of the Earth’s Surface)
- Most of the Earth’s interior
- It is so hot that rocks melt and move slowly in giant currents
- Layer after Crust
Outer Core
(Layers of the Earth’s Surface)
- Mainly made up of liquid metals (iron)
- Very hot (up to 6000°C)
- Layer after Mantle
Inner Core
(Layers of the Earth’s Surface)
- Centre of the Earth
- High temperatures (up to 10 000°C)
- Extreme pressure as the rest of the Earth pushes down on it
What are Converging and Diverging Tectonic Plates?
Converging= Pushed into one another
Converging Tectonic Plates create huge mountain ranges (eg. Himalayas and Andes).
Diverging= Pulled apart from one another
Diverging creates rifts that allow hot magma to ooze to the surface and create new land.
How are Earthquakes triggered through the movement of Tectonic plates?
Earthquakes are triggered when the edges of tectonic plates push and grind against one another.
(converging- 80% of the time)
How are Earthquakes formed through the movement of Tectonic plates?
Earthquakes occur along fault lines. They occur where plates are subducting, spreading, slipping, or colliding. As the plates grind together, they get stuck and pressure builds up (rumble). Finally, the pressure between the plates is so great that they break loose.
How are Volcanoes formed through the movement of Tectonic plates?
Volcanoes are formed when magma is pushed through an opening in the Earth’s crust.
(converging)
What are 5 facts about Tectonic Plates?
- Crust is broken into large pieces called tectonic plates
- Plates are around 100 km thick
- Current in magma under these tectonic plates causes them to move
- Movement of tectonic plates impacts and creates landscapes
- Responsible for volcanoes and earthquakes
How are the Three Types of Mountains classified?
Classified according to how they are formed.
- Fold Mountains
- Block Mountains
- Volcanic Mountains
What are Fold Mountains?
- Created by upward pressure where two tectonic plates collide
- Layers of rock are buckled and pushed upwards
- Highest Mountain Ranges
Eg.
1. Mantle currents moving the Indo-Australian plate northwards
2. Front edge is bulldozing into the Eurasian plate
3. This folds both plates upwards
What are Block Mountains? (faulting)
- Created when cracks – known as faults – force blocks of land upwards
- Cooler rocks tend to crack and break apart when compressed
- Lifted up in giant blocks along fault lines
- Geologists refer to this mountain-building process as faulting
What are Volcanic Mountains?
How do volcanic mountains erupt?
- Created by volcanoes
- Magma pushes its way from beneath the Earth to the crust
- Lava builds upon surface and creates new landforms
- Located near plate boundaries
- Plates collide and one plate is forced downwards into the mantle
- Causing magma to force its way out through a weakness in the crust
What are the two types of
Volcanic Mountains?
Shield Volcanoes and Volcanic cones
What are Shield Volcanoes
What are Volcanic Cones?
Shield Volcanoes
1. Eruption brings lava to surface
2. Lava builds up the height of the land in layers
3. Runny lava travels many km leaving behind shallow layers of new rocks
4. Eg. Hawaiian volcanoes and Mount Kilimanjaro in Tanzania
Volcanic cones
1. Formed when lava and ash are left as a new layer on the sides of the cone, building it higher
2. Eg. New Zealand’s Mount Taranaki and Mount Fuji in Japan
