THE INTERNAL STRUCTURE OF THE EARTH

Question 1

The crust

Answer 1

5-20km thick beneath the ocean and 70km thick under continant

Question 2

2 types of crust

Answer 2

oceanic and continental

Question 3

oceanic crust

Answer 3

broken layer of basaltic rocks known as sima
6-10km thick
less than 200million years old
3.0 density (heavier)
composition is mainly basalt: silicon, magnesium, oxygen

Question 4

continental crust

Answer 4

mainly granite rocks known as seal.
30-70km thick
over 1500 million years old
2.6 density (lighter)
composition is mainly granite silicon aluminium and oxygen

Question 5

what’s the lithosphere

Answer 5

consists of the crust and rigid upper section of the mantle

Question 6

how thick is the lithosphere

Answer 6

80-90 km thick

Question 7

what’s the lithosphere divided into

Answer 7

7 large plates and number of small ones.
consists of two types -continental and oceanic

Question 8

what is the Moho boundary

Answer 8

boundry zone between earths crust and mantle
marks a change n seismic wave velocity from crust to mantle within the lithospheric plate.

Question 9

asthenosphere

Answer 9

up to 5% semi molten layer of the mantle
lies beneath the lithosphere and semi molten of which the plates are able to move

Question 10

mantle

Answer 10

rust coloured
gets close to melting but doesn’t actually melt
thickest section of earth at 2900km
rocks are in a thick semi molten due to its si.icate rock content
upper mantle rocks are solid and sit on top of the athesonsphere.
the asthenosphere moves very slowly carrying lithosphere on top.