Formation of Coastal Landforms

Question 1

Formation of a spit

Answer 1

1) transport of beach material (sand, shingle) by longshore drift in one dominant direction
2) beach material transported towards the distal end of beaches into open water
3) deposition where wave energy is reduced
4) spit grows across a bay, estuary, river mouth or where there is an abrupt indentation of the coast
5) most spits associated with coastlines that have a LOW tidal range
- part of the spit closest to land is the PROXIMAL end
- part of spit furthest away is the DISTAL end
- all spits are DYNAMIC landforms, can change due to marine processes and supply of material

Question 2

Formation of a cliff

Answer 2

1) Cliffs typically form through erosion where waves break repeatedly on steeply sloping coastlines.
2) processes like hydraulic action and abrasion cause undercutting between the low and high tide levels, forming a wave-cut notch at the base of the cliff
3) continued undercutting weakens support for the rock, leading to collapse and the formation of a steep cliff face as the cliff retreats landward.
4) regular removal of debris at the foot of the cliff means the cliff profile stays steep, and that it retreats parallel to the cliff
5) Factors such as geology, wave energy, and coastal morphology influence the shape of the cliff and erosion rates

Question 3

Cave, Arch, Stack, Stump formation

Answer 3

1) form through erosion and weathering of coastal rock formations, often made of bands of more resistant and less resistant rock layers.
2) wave action exploits existing weaknesses in the rock, such as joints, faults, or bedding planes, creating erosional features like caves.
3) further erosion widens these caves, eventually breaking through headlands/cliffs, forming arches when caves align
4) isolated rock formations (stacks) are left behind as the arch becomes wider and the roof eventually collapses due to gravity+erosion (@ base=erosion, on face=weathering).
5) stacks undergo further erosion at the base, leading to collapse + formation of stumps.
6) happen over thousands of years, leading to series of distinctive coastal landforms, e.g. Old Harry, Dorset Coast.

Question 4

Shore platform formation

Answer 4

1) flat, wave-cut surfaces @ base of cliffs/rocky coastlines.
2) form through a combination of erosional processes, including hydraulic action, abrasion, and corrosion
3) the relentless pounding of waves weakens + wears the base of cliffs, resulting in the retreat of the cliff face.
4) As cliff retreats, a flat rocky platform is left behind at the former shoreline level.
5) platform is continually reshaped by wave action, which smooths and levels the surface through abrasion and transports eroded material away from the coastline.
6) Shore platforms often extend seawards, providing a relatively stable area for marine life and serving as a buffer against further erosion.

Question 5

formation of beaches

Answer 5

1) Beaches are depositional landforms made of loose sediment, typically sand or pebbles.
2) Sediment is transported to the coast by LSD, where waves approach the shore at an angle and move sediment along the coastline.
3) As waves approach the coast, their energy decreases, causing sediment to be deposited in a characteristic concave shape known as a beach.
4) Beaches can vary in size, shape, and composition depending on wave energy, sediment supply, and coastal morphology.
5) dynamic environments, are constantly reshaped by the flow of tides, storms, and seasonal variations in wave activity.

Question 6

formation of tombolos

Answer 6

1) depositional landforms that connect an island to the mainland or another island
2) typically occurs when sediment is transported by LSD and deposited between mainland and an offshore island.
3) Over time, sediment accumulates and builds up, creating a land bridge or isthmus that connects the island to the mainland.
4) Tombolos often have a curved or fan-shaped morphology, showing the direction of LSD and wave action.
5) can vary in size and shape depending on factors such as sediment supply, wave energy, and coastal currents.
6) play important roles in coastal geomorphology, providing access to islands and influencing coastal processes such as erosion and sediment transport.

Question 7

formation of bars

Answer 7

1) depositional landforms, parallel to the shoreline, extending across bays, estuaries, or coastal lagoons.
2) typically composed of sand, gravel, or other sediment deposited by LSD or tidal currents.
3) form when sediment transported along the coastline encounters a sheltered area or a change in coastal morphology, causing deposition to occur.
4) gradually as sediment accumulates it builds up above sea level, forming a submerged/emergent ridge parallel to the shoreline.
5) can act as barriers, separating coastal waters from open ocean + creating sheltered environments e.g lagoons or coastal wetlands.
6) dynamic features, constantly reshaped by movement of sediment + action of waves, tides, and currents.

Question 8

formation of salt marshes

Answer 8

1) coastal wetlands that form in sheltered areas such as estuaries, lagoons, and behind barrier islands.
2) develop in locations where sediment deposition > erosion rates, accumulating organic-rich mud and silt.
3) characterized by a unique vegetation community adapted to saline conditions, including salt-tolerant grasses, sedges, and shrubs.
4) These plants help stabilize sediment and trap organic matter, contributing to the formation of marsh soils and promoting habitat diversity.
5) provide important ecological functions, such as coastal protection, erosion control, nutrient cycling, and a habitat for diverse plant and animal species.
6) highly productive ecosystems, supporting a variety of marine and terrestrial organisms and providing valuable ecosystem services to coastal communities.