Rocks Flashcards
How are igneous rocks formed?
Magma or Lava solidifies
What type of crystals do they have and how big are they?
Interlocking crystals and if the rock cooled quickly they will be small and if it cooled slowly they will be big
Give an example of an igneous rock with small and large crystals
Small- basalt
Big- granite
What do interlocking crystals do?
Makes the rock hard and resistant to erosion
How are sedimentary rocks formed?
When layers of sediment are compacted together over a very long time by being burned under more layers
What may sedimentary rocks contain?
Fossils
What is an example of a sedimentary rock
Chalk and limestone which are natural forms of calcium carbonate
How are metamorphic rocks formed?
From existing rocks by the action of heat (from being burned or nearby magma) and pressure (from being buried) which causes new interlocking crystals to grow.
Give an example of a metamorphic rock
Marble which is formed from chalk or limestone
