Geography: Coastal Features and Processes

Graph Essentials

• A graph typically includes a border, orientation, legend, title, scale, and source.

Longshore Drift

• Dominant prevailing wind direction pushes waves at an angle, creating a swath.
• Sediment is picked up and dragged back into the sea through backwash.
• Fetch is the distance in which the wind blows over the sea.
• Waves are formed by wind blowing across the surface of the sea, creating small ripples that develop into waves.
• Constructive waves have little energy and are responsible for building up beaches.
• Destructive waves have a lot of energy, breakwaters, and a weak swash but a strong backwash.

Coastal Erosion

• Abrasion: relative particles in the water scrape and rub against the rock, removing small pieces.
• Hydraulic action: waves crashing against rocks and compressing the air into the cracks.
• Attrition: eroded particles in the water smash into each other and break into smaller pieces, with edges getting rounded off.
• Corrosion: sea water dissolved rocks like chalk and limestone using carbonic acid.

Erosion Landforms

• Caves: created by the dissolution of soluble rocks like limestone by acidic water.
• Arches: formed by the erosion of softer rock beneath harder layers.
• Stacks and Stumps: remnants of sea cliffs eroded by wave action, with stacks being isolated pillars and stumps being the base of eroded stacks.
• Spits: formed by the deposition of sediment by longshore drift, extending from the shoreline into open water.

Deposition Landforms

• Beaches: serve as recreational areas, wildlife habitats, and buffers against erosion, and are important for tourism and coastal economies.
• Spits: provide protection to coastlines.
• Bars: influence coastal dynamics by affecting wave patterns and sediment transport.
• Tombolos: connect islands or offshore rocks to the mainland, providing accessibility and sometimes acting as protective barriers against wave action.
• Sand dunes: stabilize coastal ecosystems, protect inland areas from storm surges and erosion, and provide habitats for specialized plant and animal species.

Plate Tectonics

• Convection currents: circular motion of magma in the mantle driven by heat from the Earth's core, responsible for the movement of tectonic plates.
• Plate boundaries: include constructive, destructive, and transform boundaries.
• Continental drift: theory proposing that continents were once joined as Pangaea and drifted to their current positions.
• Sea floor spreading: new oceanic crust forms at mid-ocean ridges through volcanic activity, supporting plate tectonics.
• Fold mountains: formed by the folding of rock layers due to tectonic compression.
• Earthquakes: sudden shaking of the ground caused by the release of energy from tectonic plates.