Plate margins and plate tectonics

Plate margins and plate tectonics
 There are 4 layers of the Earth - Crust, Mantle, Outer Core and Inner Core

Inner Core

o Located at the centre of the Earth.
o Hottest layer which has temperatures up to 5500 degrees Celsius
o Made up of iron and nickel

Outer Core

 Layer surrounding the inner core.

Mantle

 Liquid layer made up of nickel and iron.
 Thickest layer of the earth at approximately 2900 Km.
 Made up of semi - molten rock called magma.

Crust

 0-60 Km thick
 Thin layer is solid.
 Made of huge pieces of land called tectonic plates which fit together like a jigsaw
puzzle.
 Thin upper layer is crust (located above lithosphere), 5Km and 30 Km.
o lithosphere (located just below the crust) thickness, 50 Km and 200 Km.
o Lithosphere is brittle and is is prone to breakage.




There are 2 types of crust:
 In 1965, the term ‘plate tectonics’ was first used.
 The Earth’s surface was believed to be divided into 7 major and 8 minor lithospheric
plates
 Plates sit on top of the mantle (semi-molten rock). This makes it easier for the plates
to move easily.