In this section, you will learn: z how two types of sedimentary rock – limestone and sandstone – are formed
z the characteristics of limestone and sandstone and where they are found in Ireland
z how people interact with sedimentary rocks and use them to their advantage.
Limestone and sandstone are the most common sedimentary rocks in Ireland.
Limestone Colour: Grey Texture: Coarse grained
Formation: The limestone in Ireland was formed about 350 million years ago when Ireland was located close to the equator. Limestone is made from particles of shells and the remains of skeletons of sea creatures. When these particles sink to the seabed they are called sediment. The sediment piled up at the bottom of a warm, shallow sea over millions of years. The weight of the upper layers of sediment compressed and cemented the lower layers of sediment into strata (layers) of solid rock.
Limestone is permeable. This means that water can pass through it. It is also soluble, which means that it dissolves in water.
Use: Limestone is often used to make monuments. It is used in the construction of buildings, and to make cement. It is also ground down into lime and added to soil to improve soil fertility.
Go to Chapter 16 to learn more about the connection between soil and rocks.
Example: Limestone is the most common type of rock in Ireland. We will learn more about the limestone landscape in the Burren, one of the biggest tourists attractions in the west of Ireland, in Chapter 6.
Formation: Sandstone is formed from sand that has been worn away from the Earth’s surface. This sand is carried by the wind and rivers and then deposited as sediment in seas, lakes and deserts, where the layers build up over time. The layers are compressed and cemented together to form sandstone.
