How Sedimentary Rocks are Formed

Sandstone

An area of sand is deposited.

The sand is made of loose particles

The particles are compacted over time.

A matrix is introduced to the sand.

Over time, the particles are cemented together.

A layer of sandstone is formed.

Shale

A basin is a low area of land.

Sometimes, a basin can be flooded by high water.

This water can contain particles of silt and clay.

This becomes an area of shallow, slow moving water.

Plants and dead organisms are absorbed into the clay and silt.

Over time,the water evaporates and the clay dries to become shale.

Limestone

Fish and shell creatures have calcium in their bones and shells.

These organisms die and settle to the sea floor.

Calcium (Ca) from the shells is dissolved into the sea water.

Live fish breathe out carbon dioxide (CO2) into the water.

Calcium (CA) mixes with the carbon dioxide (CO2) to form………………

CALCITE

Calcite settles to the bottom and mixes with sand and clay.

Over time, the weight of the sea water compacts the calcite, clay, and sand.

The sediments eventually compact enough to form solid rock – Limestone.