Igneous and metamorphic rocks give us some clues about what is happening deep within the earth, or at the surface, where magma forms new rocks. Sediments give us a record of what has been happening at the earth’s surface over the past thousands and millions of years.

Different sediments are laid down in different environments, with different climates. If we look at the rocks around us they give us a clue to the past ‘geological history’ and climate of Britain. The geology of Great Britain records the passage of our island from south of the equator to its current position.

• In the South East of Britain the rocks are mainly chalk, sandstone and clays. Chalk is a well known type of rock made up of minute skeletons of billions of tiny sea creatures.

• In the North of England, the commonest type of rock is limestone, which is also made up of the skeletons of sea creatures, shells and corals.

Both of these rocks were laid down in the warm seas of a tropical climate, imagine that England once had a climate like the Bahamas has today, with warm seas and coral reefs.

• Parts of Wales, Scotland and Ireland have rocks that indicate another period when the British climate was much hotter than it is today. Red sandstone in these areas was laid down in a hot, arid desert environment.

• At the other extreme, North Wales and the English Lake District have rocks like shales and mudstones, that were formed in deep cold water. Intruding into all these sedimentary rocks are igneous rocks like granite, and we even have ancient volcanoes and lava flows.

Of course our landscape is not only characterised by the rocks that form it, it has also been shaped by the weather. In the ice age, glaciers and great ice sheets carved out deep wide valleys in the landscape and left mounds of gravel and sheets of boulder clay when the ice melted and retreated. You can find out more in ’The Big Freeze – from Icehouse to Greenhouse’.

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