Earths Structure Flashcards
1
Q
What is the lithosphere?
A
- rigid
- directly above the Asthenosphere/ below crust
- thickness varies
2
Q
What is the asthenosphere?
A
- semi-molten rock capable of flowing slowly
- thickness between 80-200km
- depth between 100km - 300km
3
Q
What is the mantle?
A
- solid
- 80% Earth’s volume
- depth of 2600km
- density of 3.3kg/m³
- consists of low density materials (magnesium /iron)
4
Q
What is the outer core?
A
- liquid
- thickness of 2260km
- composed of iron and nickel
- density of 10-12kg/m³
- movement is responsible for the Earth’s magnetic field
5
Q
What is the inner core?
A
- solid
- thickness of 1220km
- iron-rich
- density of 13.6kg/m³ (5x denser than surface rocks)
6
Q
What are the characteristics of continental crust?
A
- carries land
- makes up 40% of the Earth’s surface
- thickness between 30 - 70km
- density of 2.6kg/m³
- rock type is granite
- mineral content of silica & aluminium (sial)
- has greater buoyancy than the oceanic crust, hence its longevity of over 1500 million years old
7
Q
What are the characteristics of oceanic crust?
A
- makes up the sea floor
- thickness of only 5 - 9km
- density of 3kg/m³ floats scarcely on the mantle
- consists of dark-coloured rocks made up of the igneous rock, basalt
- mineral content of silica & magnesium (sima)
- less than 200 million years old (occasionally sinks into hot molten mantle were it melts and is recycled)
