The Three Different Types Of Rock

Question 1

Give two examples of sedimentary rock and describe their characteristics.

Answer 1

Limestone and chalk.

• contain fossils (not formed at high temperatures, so remains/imprints of animals are still intact)
• easily eroded

Question 2

How are metamorphic rocks formed?

Answer 2

Metamorphic rocks are formed by heat and pressure on sedimentary rocks over long periods of time.
The mineral structure and texture may have changed, but the chemical composition of the rock often remains the same.

Question 3

Give and example of metamorphic rock.

Answer 3

Marble.

• formed from limestone or chalk.
• high temperatures break down the limestone and it reforms as small crystals.
• marble has a more even texture and makes it much harder

Question 4

How are igneous rocks formed?

Answer 4

Igneous rocks form when molten magma pushes up into the crust (or right through it) before cooling and solidifying.
They contain various different minerals in randomly arranged interlocking crystals.

Question 5

Name and define the two types of igneous rock.

Answer 5

EXTRUSIVE Igneous rocks cool QUICKLY ABOVE GROUND forming SMALL crystals, e.g basalt and rhyolite

INTRUSIVE igneous rocks cool SLOWLY UNDERGROUND, forming BIG crystals, e.g granite and gabbro

Question 6

Give an example of igneous rock.

Answer 6

Granite

• very hard
• ideal for steps or buildings

Question 7

How are sedimentary rocks formed?

Answer 7

From layers of sediment laid down in lakes or seas. Over millions of years, the layers get buried under more layers and the weight pressing down squeezes out the water. Fluids flowing through the pores deposit natural mineral cement.