COMPOSITION OF EARTH The structure of the earth’s interior is three layered and are named as crust, mantle and the core.
Crust
Crust is the outer thin layer with a total thickness of around 100 km. It forms 0.5% of the earth’s volume. The outer covering of the crust is of sedimentary material and below that lies crystalline, igneous and metamorphic rocks.
Composition of earth crust:
The earth’s crust is principally composed of mineral matter. The mineral matter is made up of various elements combined together to form compounds. Some elements exist as such without forming compounds. Out of 106 elements known, 8 are sufficiently abundant and constitute about 99 percent by weight of the earth’s crust.
Element Amount
Non-metallic
Oxygen ( 75 % of earth crust) 46.60
Silicon 27.72
Oxygen is most abundant in earth crust.
Metals
Aluminium 8.16 25% of earth’s crust
Iron 5.00
Calcium 3.50
Sodium 2.83
Magnesium 2.09
Potassium 2.59