The dense, semi-molten layer below the crust that is about 5000 degrees
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What are convection currents?
Hot liquid rock rises from the core then cools, flowing outwards and downwards where it is re-heated
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What is magma?
Melted rock below the crust
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What is lava?
Magma that has reached the earths surface
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What is the core?
The densest part of the earth. The inner core is solid iron and nickle at 6000 degrees, the outer core is semi-molten and slightly cooler
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Name two oceanic plates
Nazca plate and the Pacific plate
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Name two continental plates
African plate and the Eurasian plate
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Which type of plate is denser?
Oceanic plate
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Which type of plate is thicker?
Continental plate
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What is a plate margin?
The boundary where two plates meet
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Name 4 plate boundaries
Constructive, destructive, collision and conservative plate boundaries
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What is a constructive plate boundary?
Two plates moving away from each other
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What happens at a constructive plate margin?
Magma comes up from the mantle and cools to form new crust between the plates
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Name a constructive plate boundary
North American and Eurasian plate boundary
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What is a destructive plate boundary?
An oceanic plate and a continental plate moving together
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What happens at a destructive plate margin?
The oceanic plate subducts under the continental plate creating an ocean trench. The excess magma is forced up through crack in the continental plate erupting as volcanoes
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Name a destructive plate boundary
Nazca plate and the South American plate
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What is a collision plate boundary?
Two continental plates moving towards each other
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What happens at a collision plate boundary?
Rocks and land are forced upwards. Rock strata becomes deformed and fold mountains are formed
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Name a collision plate margin and the mountain range formed as a result
Indian and Eurasian plate forming the Himalayas
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What is a conservative plate margin?
Two plates sliding past each other in opposite directions or at different speeds
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What happens at a conservative plate boundary?
The plates get stuck and pressure builds up until there is a sudden movement which causes earthquakes
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Name a conservative plate boundary
Pacific Plate and the North American plate forming the San Andreas Fault
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Where are fold mountains formed?
At both destructive and collision plate boundries
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Where are ocean trenches found?
At the subduction point of an oceanic plate at a destructive plate boundary
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What are young fold mountains?
Mountains formed in the last 65 million years, usually very tall e.g. Himalayas
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What are old fold mountains?
Mountains formed over 100 million years ago, usually less high due to erosion e.g. Cambrian mountains
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