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The Rock CycleThe Rock Cycle

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Sedimentary rocksSedimentary rocks

Sandstone

Conglomerate

Limestone

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Sedimentary rocksSedimentary rocksHow sedimentary rocks are formed:

1) Weathering

2) Transportation

4) Burial

3) Deposition

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Sedimentary rocksSedimentary rocks

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Metamorphic rocksMetamorphic rocks

Slate

Marble

Quartzite

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Metamorphic rocksMetamorphic rocksMetamorphic rocks are formed by the combined effect of heat and pressure on other rocks:

Pressure from rocks above…

…and heat from magma nearby

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Metamorphic rocksMetamorphic rocks

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Igneous rocksIgneous rocks

Granite

Pumice

Obsidian

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Igneous rocksIgneous rocks

Igneous rocks are formed when lava or magma cools down and solidifies

If the lava or magma cools QUICKLY it has SMALL crystals

If the lava or magma cools SLOWLY it has BIG crystals

08/04/23Crystal sizes in igneous Crystal sizes in igneous rockrock

The size of the crystals in igneous rock shows how quickly the rock had cooled.

SLOW cooling = BIG crystals

FAST cooling = SMALL crystals

e.g. this rock will cool ____, so the crystals will be ____

This rock will cool _____, so the crystals will be _______

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Igneous rocksIgneous rocks

Magma

Extrusive igneous

rock

Intrusive igneous

rock

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SummarySummarySedimentary,

igneous or metamorphic?

How they were formed

Appearance

(e.g. sandstone, limestone, chalk)

Small pieces of sediment were stuck together by salt and pressure from rocks above

Usually soft, can contain fossils, easily eroded

(e.g. basalt, granite)

Liquid rock (magma or lava) cooled down and turned back into a solid

Contain crystals, very hard, never contain fossils

(e.g. marble, slate)

Other rocks were acted on by heat and pressure over a long time

Sometimes have tiny crystals, no fossils, always hard and sometimes arranged in layers

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The Rock CycleThe Rock Cycle

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Rocks revision quizRocks revision quiz

1. What are the 3 types of rock?

2. What type of rock are the following:

Sandstone, limestone, granite, basalt, slate

3. What type of rock would a mountain probably be made out of?

4. What are the two conditions needed for a metamorphic rock to form?

5. Which metamorphic rock is formed from limestone?

6. Why wouldn’t you find any fossils in igneous or metamorphic rocks?

7. You find a rock containing crystals. What type of rock would it most probably be?

8. What is molten rock that is inside the Earth called?

9. What is molten rock that is outside the Earth (i.e. erupted) called?

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Rocks revision quizRocks revision quiz

10. Name one example of physical weathering.

11. Name one example of biological weathering.

12. Acid rain is an example of chemical weathering. What poisonous gas (given off by car exhausts and power stations) causes acid rain?

13. Granite is an igneous rock and contains large crystals. Did it cool down slowly or quickly?

14. In the rock cycle what causes igneous rock to become sedimentary rock?

15. In the rock cycle again what causes the sedimentary rock to become metamorphic rock?

16. Gravestones are usually made out of marble or granite instead of limestone or sandstone. Why?

17. A piece of rock contains layers. What type of rock would it probably be?