Edexcel GCSE Geography - Physical Landscapes Revision

Physical Landscapes

Classification of Rocks:

  • Igneous Rocks -   * Formed by magma from the molten interior of the Earth   * If magma cools inside the Earth it forms intrusive rock, which may later be exposed by erosion and weathering, e.g. granite.   * If magma erupts on the surface as lava, it will form extrusive rock, e.g. basalt.   * As the magma cools, mineral crystals will begin to grow. These crystals will grow and interlock to form a hard crystalline rock.
  • Sedimentary Rocks -   * Sedimentary rocks are formed from sediment (from eroded rocks and cliffs) that has settled at the bottom of a lake, sea or ocean, and have been compressed with pressure over millions of years.   * Examples of sedimentary rocks include limestone, sandstone, chalk and mudstone.   * The weathered and eroded material is built up in layers. As more material is added on top – this will push any air and/or water out and will compact the material together into a hard rock.   * Often contain fossils
  • Metamorphic Rocks -   * Metamorphic rocks have been subjected to lots of heat and / or pressure, causing them to change into another type of rock.   * They are usually resistant to weathering and erosion and are therefore very hard-wearing, making them good building materials.   * Examples of metamorphic rocks include marble, which originates from limestone and slate, which originates from clay.   * These are formed when either igneous or sedimentary rocks are changed.

\ has

Coasts:

Longshore Drift:

  • Waves are forced against the cliffs at angles due to prevailing winds
  • This takes sediment with it and pushes it further down the cliff
  • This continues over years, pushing this further down the cliff

\

Weathering:

  • Physical Weathering -   * Water gets into a crack in a rock   * At night, this freezes and expands   * This continues until the rock falls off the cliff
  • Chemical Weathering -   * Rainwater is slightly acidic   * As this falls against the cliffs, it slowly wears it down   * Over years, these rocks become dissolves
  • Biological Weathering -   * A plant grown in a crack in a rock   * As this grows, it requires more space, widening this crack   * Over time, this plant pushes the rock away from the cliff

\

Mass Movement:

  • The downhill movement of sediment moving because of gravity.
  • Rockfall -   * Bits of rock fall off the cliff face, usually due to freeze-thaw weathering.
  • Mudflow -   * Saturated soil (soil filled with water) flows down a slope.
  • Landslides -   * Large blocks of rock slide downhill.
  • Rotational Slip -   * Saturated soil slumps down a curved surface.

\

Wave Types:

  • Destructive Waves -   * Waves that attack the cliff face to erode rock
  • Constructive Waves -   * Waves that take up the sediment from eroded rock

\

Rivers:

Floodplains and Levees:

  • A river deposits sediment to its banks
  • Every 2 - 3 years, this river floods
  • This deposits sediment onto the sides of the river
  • This sediment forms natural walls on the sides of the rivers, called floodplains or levees
  • This is a natural flood defence

\ \ \ \