1.3 Landforms and plate movements Flashcards
What are the 3 kinds of plate boundaries
Constructive
Destructive
Conservative
What is a constructive plate boundary and which 2 landforms does it produce
When 2 plates move apart from eachother
Oceanic - Mid ocean Ridge
Continental - Rift valley
What is a Mid-Ocean Ridge and how do they form
Mid-Ocean Ridges are elevated regions of the ocean
When oceanic plates move apart, the space between them is filled with basaltic lava. The new formed crust then spreads and creates transform faults at right angles to the plate boundary, creating a ridge
What is an example of a Mid-Ocean Ridge
The Mid Atlantic ridge
2.5km high
16,000km long
What is a Rift valley and how do they form
A rift valley is a lowland valley created by the splitting of the earths crust
When continental plates move apart, the crust fractures and drops between parallel faults to form the valley
What is an example of a Rift valley
The East African rift valley (east Africa is pulling away from the continent)
600m high
4,000km long
What is a destructive plate boundary and which 3 landforms does it produce
When 2 plates collide with each other
1.DEEP SEA TRENCH (oceanic to continental, just oceanic)
- FOLD MOUNTAINS (oceanic to continental, just continental)
- ISLAND ARC (oceanic)
What is a Deep sea trench and how do they form
A long narrow, deep part of the seafloor
When the oceanic plates subducts under the continental plate, or the faster oceanic plate subducts under another oceanic plate…
the plates create a downwarping effect, forming a deep trench
Give an example of a deep sea trench
The Marianas trench, which is 11,000metres deep
What is a fold mountain and how do they form
Large mountains
When 2 continental crust meet there is no subduction, so as they move towards each other, their edges and sediments are forced downward together to create fold mountains which grow over time
When oceanic subducts underneath continental , sediments which accumulated along the oceanic plate become uplifted
Give an example of a fold mountain
The Himalayas 8,850m high
What is an island arc and how do they form
An island arc Is a chain of volcanic islands located at a tectonic margin
During subduction, the descending plate melts. Once melted, it is less dense than the asthenosphere so rises to the surface as a pluton of magma, and eventually form a volcano
Give an example of an island arc
The Marianas islands is made up of 14 islands
What is a conservative plate boundary and what landforms does it produce
When 2 plates slide past each other in opposite directions, or in the same direction at a different speed
They do not create or destroy crust, but do cause major earthquakes and can form Fault lines
What is a fault line and give an example
A fault line is a fracture in a rock that traces a geological fault such as the San Andreas fault line, which is 12,000km
