Geology maps
The British Geological Survey (BGS) create detailed maps of the rocks found below Great Britain.
British geology
Great Britain lies over a variety of rock types. These rocks formed at different times under different environmental conditions. For example, mudstone is a A type of rock formed by the deposition of material at the earth's surface. that formed over 200 million years ago when the UK was a desert.
Rocks determine the shape of the land and also the soil type and The way in which water drains from the land. For example, soils that form over A type of sedimentary rock. rock are Having a pH greater than 7. and dry. Certain crops prefer these conditions, eg asparagus crops will grow in alkaline soils and they have deep roots so they survive dry conditions.
It is not easy to work out what type of rock lies below ground, except in areas where the soil and vegetation is very thin, eg mountains. This is why The study of rocks. maps are useful.
What do geological maps look like?
Geological maps are colourful. Each different rock type is shown using a colour and/or a number. The network of roads and settlements is shown as a faint layer beneath these colours.
Geological maps also show major A fracture in the Earth's crust. which are cracks in the rock, and major Rocks that have been pushed upwards and over the rocks above. where rock has been forced upwards. Faults are shown as a solid black line and thrusts are shown as alternative dashes and dots.
This geology map shows that the Isle of Wight (to the east of the map) has the same geology as Swanage (the coastline to the west of the map). The bright green rock that protrudes from the coastline at both Swanage and the Isle of Wight is hard chalk that is Able to withstand change, eg resistant rocks are hard and are not easily eroded. to coastal The wearing away of pieces of rock, soil or other solid materials.