Geography

• The UK is made up of many rock types, but the three main groups are sedimentary, igneous and metamorphic
• Main UK rock types

  • Sedimentary - chalk, sandstone
  • Igneous - granite, basalt
  • Metamorphic - schist, slate
• Sedimentary rocks are formed in layers called beds. They often contain fossils
• Chalk


  Made up of calcium carbonate, susceptible to chemical weathering
• Sandstone


  Made of sand-sized grains cemented together, can be hard and resistant to weathering, but is permeable
• Igneous rocks are hard and formed of crystals so are resistant to erosion. They are usually impermeable - water doesn't pass through them
• Granite


  Affected by chemical weathering, landscapes drain badly so tend to be boggy
• Basalt


  A grey rock made from very small crystals, formed from lava flows cooling
• Metamorphic rocks


  Formed by great heat and pressure, examples are schist and slate
• Slate


  Formed from mudstone at convergent plate boundaries
• Schist


  Formed at higher pressure at the same plate boundary as slate
• The UK is split into two halves geologically. The north-western UK is mainly harder igneous and metamorphic rocks, forming upland landscapes. The south-eastern UK is mainly softer sedimentary rocks, forming lowland landscapes
• Millions of years ago the UK was close to plate boundaries. Plate movements caused mountains (huge folds) and faults in the rocks
• 520 million years ago two plates converged to form upland mountain landscapes - northern Scotland, the Lake District and North Wales
• 50-60 million years ago diverging plate boundaries caused the Atlantic Ocean to open. Rising lava produced the distinctive basalt geology of the Giant's Causeway
• Sedimentary rocks are much softer and more easily eroded than igneous and metamorphic rocks. Therefore sedimentary rocks are worn down rapidly to form low hills and lowland basins
• Upland Britain is made up of igneous and metamorphic rocks because these harder rocks are more resistant to erosion than the softer sedimentary rocks
• Glacial erosion carved out a corrie (Stickle Tarn) in the Lake District during the Ice Age
• Weathering leads to rock fragments breaking off and falling to the base of cliffs to form a scree slope
• High precipitation in the Lake District means there is a lot of surface drainage over the impermeable rocks, resulting in many streams
• The flat bottom and steep sides of the valley in the Lake District show it is a U-shaped valley formed by a glacier
• River erosion has eroded a wide valley between low hills in Herefordshire
• Prolonged heavy rain can cause rivers to flood, depositing silt to form a wide, flat floodplain
• Granite landscapes on Dartmoor formed when a dome of magma developed underground, cooled and contracted to form granite with cooling joints. Chemical weathering widened the joints, and freeze-thaw weathering, erosion and mass movement removed the broken granite, leaving behind outcrops of rock less affected as tors
• Chalk is not formed of crystals
• Settlements grew up in lowland landscapes where the land was flat and easy to build on, with advantages like river meander loops, coastal plains, natural harbours and shallow river fords. Over time, settlements spread across the landscape, with many streams and small rivers now running in underground tunnels
• Upland landscapes of hills and mountains make it more difficult to construct settlements, so are less built up than lowland landscapes
• Shrewsbury was likely chosen as a settlement site due to its location on a river, which would have provided advantages like water supply, transport and defence
• Weathering helps wear away rocks but leaves weathered material in situ. There are three types: chemical, biological and mechanical
• Mass movement is the downhill movement of material under the influence of gravity. Types include sliding and slumping
• Slumping happens when rocks are saturated, causing loose, wet rocks to slump down under gravity along curved slip planes, often on clay coasts
• Sliding happens when loosened rocks and soil suddenly slide down the slope, with blocks of material all sliding at once
• Waves transport eroded material along the coast by traction, saltation, suspension and solution
• Longshore drift is the process by which beach sediment can be transported along the coast by waves, with the sediment moving in a zigzag pattern determined by the prevailing wind direction
• Waves deposit material in sheltered spots, calm conditions and gentle offshore gradients, which reduce the wave's energy
• Geological structure, rock type and wave action all influence coastal landforms. Soft rock is eroded much faster than hard rock
• Longshore drift transports material along the coastline

  1. Direction of material movement is determined by prevailing wind direction

  2. Waves approach coastline at acute angle, bringing sediment onto beach in swash

  3. Sediment dragged back to sea in backwash under gravity at right angle

  4. Process continues in zigzag pattern, moving sediment along beach
• Concordant coasts


  • Made up of same soft rock type
• Discordant coasts


  • Rock type alternates, forming headlands and bays
• Destructive waves


  Swash is weak, backwash is strong, material dragged into sea, eroding coast. High energy, occur in stormy conditions.