The Structure of The Earth
OCEANS
Depths:
Average depth - 3.8 kilometres
Oceanic trenches - over 11 km
CRUST
A lighter layer of rock which makes up the
continents on which we live, and extends under all
the oceans and seas.

Average thickness:
Continental crust - 35 kilometres deep
Oceanic crust - 7 kilometres deep

MANTLE The mantle is a layer of solid silicate-type rock
between the core and the crust.

It contains more of the lighter elements: oxygen,
calcium, aluminium and silicon.

A weakness in the earth’s outer crust can cause the
upper mantle to melt to the consistency of hot tar.
This can then break through the surface as volcanic
eruptions.
CORE
Outer core:
molten and heavy, composed mainly of iron-
nickel alloys at temperatures above 4000°C
Inner core:
solid, as its temperature is below 4000°C