Tectonics KO 1

Match the letters on the diagram to the layer of the earth

• D

• crust

• A

• outer core

• B

• mantle

• C

• Inner core

Inner core = hottest layer, a ball of _____ metal (iron and nickel)

• liquid

• solid

• molten

Outer core = L________ metal (iron and nickel)

Mantle = semi-liquid molten rock that slowly moves due to ________ currents.

Crust = thin layer of solid rock divided into slabs called tectonic plates which float on the mantle. Plates are made up of: a) Oceanic crust = thinner but ______. b) Continental crust = thicker but lighter.

Constructive plate boundary: Two plates move _____ from each other. Magma (molten rock) rises from the mantle to fill the gap and cools, creating new crust, volcanoes, mid ocean ridges and rift valleys. Earthquakes occur where tension builds as they move away from each other. E.g. the mid-Atlantic Ridge / Africa rift valley.

Collision plate boundary: Two continental plates ________. Neither can sink so the land buckles up forming fold mountains and earthquakes e.g. the Himalayas.

Conservative plate boundary: Two plates _____ past each other, or in the same direction but at different speeds. Tension builds up when the plates get stuck until, eventually, they jolt forward causing earthquakes. E.g. The North American and Pacific plates.

Volcanoes and earthquakes tend to occur in long narrow belts along plate ________.

The diagram is showing the Pacific ring of ____ .