Rocks

Question 1

What are the 3 types of rock?

Answer 1

1. Sedimentary rock
2. Igneous rock
3. Metamorphic rock

Question 2

What is sedimentary rock?

Answer 2

Rocks that are formed through the deposition of sediments, eg limestone, chalk and sandstone.

Question 3

What is igneous rock?

Answer 3

Rocks that formed under very hot conditions within the Earth.

Question 4

What is metamorphic rock?

Answer 4

A type of rock formed under intense heat or pressure.

Question 5

What is compaction?

Answer 5

Compaction is what happens when sediments are squashed by the layers of sediment above them.

Question 6

What happens when sediments are compacted?

Answer 6

When sediments are compacted, water between the grains is squeezed out and crystals of different salts form.

Question 7

What can limestone be formed from?

Answer 7

Some limestones are formed from the shells of sea creatures

Question 8

What are the 6 processes of sedimentary rock formation in order?

Answer 8

weathering → erosion → transportation → deposition → compaction → cementation

Question 9

What is cementation?

Answer 9

After compaction the crystals stick the pieces of rock together like a glue. This process is called cementation.

Question 10

What is transportation?

Answer 10

A river carries, or transports, pieces of eroded rock as it flows along.

Question 11

What is deposition?

Answer 11

When the river reaches a lake or the sea, its load of transported rocks settles to the bottom. We say that the rocks are deposited.

Question 12

What chemical makes up limestone?

Answer 12

Calcium carbonate

Question 13

What is magma?

Answer 13

The inside of the Earth (mantle) is very hot - hot enough to melt rocks. Molten (liquid) rock is called magma. When the magma cools enough, it solidifies and igneous rock forms.

Question 14

How are crystals formed?

Answer 14

Igneous rocks contain randomly arranged interlocking crystals. The size of the crystals depends on how quickly the molten magma solidified.

Question 15

How are small crystals formed?

Answer 15

Lava that cools quickly will form an igneous rock with small crystals

Question 16

How are large crystals formed?

Answer 16

Magma that cools slowly will form an igneous rock with large crystals.

Question 17

What is lava?

Answer 17

The magma that comes out of volcanoes.

Question 18

What is a volcano?

Answer 18

Magma builds up under the surface and gets forced through the crust.

Question 19

Give examples of rock from cooled lava. Describe them.

Answer 19

Basalt and pumice both come from lava, which means they cooled quickly on the surface.

Basalt is a dark glassy rock which has very fine crystals often formed in columns.

Pumice is soft and cooled really fast.

Question 20

Is granite cooled quickly or slowly?

Answer 20

Granite is found deep underground. It cooled very slowly and is very hard.

Question 21

Does igneous rock contain fossils?

Answer 21

Igneous rocks do not contain any fossils. This is because any fossils in the original rock will have melted when the rock melted to form magma.

Question 22

How are metamorphic rocks formed?

Answer 22

Shifting tectonic plates can cause rocks to be deeply buried or squeezed. As a result, the rocks are heated and put under great pressure. They do not melt, but the minerals they contain are changed chemically, forming metamorphic rocks.

Question 23

Give examples of metamorphic rock

Answer 23

Marble is formed from limestone

Quartz is formed from sandstone