QUIZ 22a. Plate Tectonics and the Rock Cycle

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(a) When molten lava or cools type rocks are formed. If the lava cools quickly the crystals are eg like in rock. If the lava cools slowly deep under ground it forms larger crystals of the . type of rock. This massive underground lava 'upwelling' is sometimes called an igneous .

(b) On a much larger scale of things the edges of some land masses () which are separated by of kilometres of ocean (eg the east coast of South and the west coast of ) have which fit quite closely 'together't.

(c) They also have similar of rocks and fossils. This suggests the land masses were once part of a land mass which has and the sections been apart. Also by the rocks and you can also show that they despite being huge distances apart.

(d) The Earth's (the crust and the upper part of the mantle) is 'cracked' into a number of large pieces called . These are constantly moving at relative speeds of a per year as a result of currents deep within the Earth's semi-liquid mantle. These currents driven by released by natural processes in the metallic .

(e) At plate boundries and/or eruptions occur. Unfortunately there is great difficulty in these events and so there are sadly, regular tragedies and mass destruction in the most parts of the world.