1 Flashcards
(57 cards)
How do constructive plate boundaries create new land (oceanic)?
As the plates move away from each other, they make a gap in the crust. This means the water will come into contact with the mantle. The water cools the mantle, turning it into rock and creating new crust.
How do constructive plate bounaries result in the formation of mountains or islands?
When the mantle rises through the gap between the plates, there are sometimes volcanic eruptions. This means that more magma has risen and can make a mountain. Lots of these eruptions can make an island, such as Iceland.
What occurs at constructive plate boundaries?
Volcanoes and Earthquakes
____ volcanoes can form at constructive plate boundaries, sometimes creating islands.
Shield
Give an example of a constructive plate boundary
The mid atlantic ridge
How fast do tectonic plates move in the mid atlantic ridge? (Constructive boundary)
Approx. 7 cm a year
What type of crust do collision plate boundaries use?
Both continental
What type of crust do constructive plate boundaries use?
Both oceanic
What happens at a collision plate boundary?
Two pieces of continental crust push together, forming fold mountains. Some of one of the plate could be also subducted underneath the other one.
What are fold mountains made of? Where do you find them?
-Collision boundaries
-Made of sedimentary rocks from the ocean. These oceanic rocks are uplifted when the mountains form (or fold).
Give an example of a collision boundary
The Himalayas
(Indian plate and Eurasian plate)
What hazards occur at collision boundaries?
Eathquakes (because of tension between the two moving plates)
What is a conservatinve plate boundary? What happens here?
Two plates move opposite each other or in the same direction at different speeds. They basically slide side by side.
Conservative
What is is called when two plates meet?
The fault line
Give an example of a conservative boundary
San Andreas fault line in California
What hazards occur at conservative boundaries?
Earthquake from the build up of friction and tension. The two plates could get jammed and then suddenly unjam, releasing lots of energy.
What is a destructive plate boundary?
It is when one plate goes under another (subduction). It happens with dense oceanic crust and less dense continental crust.
What is oceanic crust made of and what does this mean at a destructive plate boundary?
- CO2, fossils and Calcium Carbonate
- When the oceanic plate melts while subducting, it realeases the CO2, producing an eruption.
Oceanic crust is more __ but __
- Dense
- Thinner
What happens to the oceanic crust at a destructive plate margin?
It is less dense than the continental crust, so it gets subducted. This causes it to melt due to high temperatures (due to friction).
What is it called where the oceanic crust is getting subducted under the continental crust (destructive)
The subduction zone
What is formed when the two plates meet at a destructive margin?
A deep ocean trench
Give an example of a destructive plate margin
South American plate and Nazca plate
What occurs at destructive plate boundaries?
Give example of mountains formed by destructive plate boundaries
Fold mountains, volcanoes, earthquakes and possibly tsunamis (Nazca plate)
The Andes are an example of these mountains
The Andes
