Rock Cycle

Earth is made up of rocks and minerals.

A rock consists of two or more minerals.Minerals are made of one or more chemicals.

Kinds of Rocks

Metamorphic Rocks

Igneous Rocks Sedimentary Rocks

Igneous Rocks

Igneous rocks are formed from liquid molten rock that cool slowly and harden.Igneous means made from fire and heat.

Sedimentary rocksSedimentary rocks are formed from sediments such as sand, pebbles, mud, shells and remains of dead plants and animals.

They hardened into rock due to pressure of water and weight of more sediments.

Categories of Sedimentary rocks

a. Clastic rocks- formed from broken fragments of pre- existing rocks and minerals.

b. Chemical rocks- formed when minerals precipitate or solidify from a solution like sea water or lake water.

c. Organic rocks- formed from accumulation of plant and animal remains.

- Limestone is made from shells of sea animals and plants. It forms only under water.

- Conglomerate is made of a mixture of smooth round stones and pebbles.

- Sandstone is made up of tiny bits of sand. It is cut into blocks and used in walls and buildings because it is strong and easy to quarry.

- Shale is made from mud and fine silt or clay. It is commonly called mudstone.

Metamorphic Rocks

Metamorphic rocks are igneous or sedimentary rocks changed by extreme heat and pressure.

Metamorphic means “to have been changed”

As a volcano pushes its way up through the earth, great heat changes a sedimentary rock into metamorphic rock.

- Marble is a metamorphic rock which comes from limestone. Minerals or impurities in the marble changes its color.

- Slate is made from shale. Slate and shale have the same colors, but they do not look alike because of how they break. Slate breaks into smooth flat sheets of rocks while shale breaks only into odd shapes.

- Quartzite comes from hard sandstone.

- Schist is made from mudstone or shale. As schist is made, some of the minerals change to become mica which make the schist shine and sparkle.

…from one type to another…And back again

Elements that make up rocks are never created or destroyed — instead, they are constantly being recycled.

The rock cycle helps us to see that the earth is like a giant rock recycling machine!

Rocks are continually…formed changed

destroyed reconstructed

In rock cycle, earth materials change back and forth among the different types of rock.