Landforms

Cards (21)

  • Erosional Landforms: Headland and bay
  • Headland and bay
    • Found in areas of alternating bands of resistant (hard) and less resistant (soft) rocks running perpendicular to oncoming waves (discordant coastline)
    • Initially, less resistant rock (e.g. clay) is eroded back, forming a bay
    • The more resistant rock (e.g. limestone) is left protruding out to sea as a headland
  • Erosional Landforms: Cove
  • Cove
    • Forms where the coastline has bands of resistant and less resistant rock running parallel to the oncoming waves (concordant coastline)
    • There is usually a band of resistant rock facing the oncoming waves, with a band of softer rock behind
    • Wave processes of abrasion, corrosion and hydraulic action will exploit faults in the resistant rock and erode through to the softer rock
    • Further wave action will erode the softer rock quickly, which will leave behind a circular cove with a narrow entrance to the sea
    • Wave refraction within the cove spreads out the erosion in all directions, creating the typical horseshoe shape
  • Erosional Landforms: Cliff and wave-cut platform
  • Cliffs
    • Shaped through erosion and weathering processes
    • Less resistant rock erodes quickly and will form sloping cliff faces
    • Steep cliffs are formed where there is harder rock facing the sea
  • Wave-cut platform
    • A wide gently sloped surface found at the foot of a cliff
    • As the sea attacks the base of a cliff between the high and low water mark, a wave-cut notch is formed
    • Abrasion, corrosion and hydraulic action further extend the notch back into the cliff
    • The undercutting of the cliff leads to instability and collapse of the cliff
    • The backwash of the waves, carries away the eroded material, leaving behind a wave-cut platform
    • The process repeats and the cliff continues to retreat, leading to a coastal retreat
  • Erosional Landforms: Cave, arch, stack and stump
  • Cave, arch, stack and stump
    • Found on a headland due to wave action and sub-aerial weathering
    • Any weaknesses in the headland are exploited by erosional processes of hydraulic action, abrasion and corrosion
    • As the crack begins to widen, abrasion will begin to wear away at the forming cave
    • The cave will become larger and eventually break through the headland to form an arch
    • The base of the arch continually becomes wider and thinner through erosion below and weathering from above
    • Eventually, the roof of the arch collapses, leaving behind an isolated column of rock called a stack
    • The stack is undercut at the base by wave action and sub-aerial weathering above until it collapses to form a stump
  • Depositional Landforms: Beach
  • Beach
    • Form in sheltered areas such as bays
    • Deposition occurs through constructive wave movement, where the swash is stronger than the backwash
    • Beach formation usually occurs in the summer months when the weather is calmer
    • Sometimes sand from offshore bars can blow onto the shore by strong winds
    • Blown sand can create sand dunes at the backshore of a beach
  • Depositional Landforms: Spit
  • Spit
    • An extended stretch of sand or shingle that extends out to sea from the shore
    • Spits occur when there is a change in the shape of the coastline or the mouth of a river, which prevents a spit from forming across the estuary
    • A spit may or may not have a 'hooked' end, depending on opposing winds and currents
    • Sediment is transported by longshore drift
    • Where the coastline changes direction, a shallow, sheltered area allows for deposition of sediment
    • Due to increased friction, more deposition occurs
    • Eventually, a spit slowly builds up to sea level and extends in length
    • If the wind changes direction, then the wave pattern alters and results in a hooked end
    • The area behind the spit becomes sheltered, and silts are deposited here to form salt marshes or mud flats
  • Depositional Landforms: Bar
  • Bar
    • When a spit grows across a bay, and joins two headlands together, a bar of sand is formed (sandbar)
    • Sandbars can also form offshore due to the action of breaking waves from a beach
  • Depositional Landforms: Lagoon
  • Lagoon

    • A small body of water cut off from the sea
    • A lagoon may form behind a bar or tombolo
    • Lagoons do not last forever and may fill with sediment and form new land
  • Depositional Landforms: Tombolo
  • Tombolo
    • Formed when a spit joins the mainland to an island
  • Depositional Landforms: Barrier Island
  • Barrier Island
    • Form parallel to the coast
    • The main difference between a bar and barrier island is that a bar joins two headlands, whereas a barrier island is open at one or both ends