Shingle Beach:
When sea levels fell as the volume of land-based ice grows, areas of ‘new’ land emerged
from the sea. As sea levels rose former coastal sediment is pushed onshore by wave action.
• Sediment accumulates on new land due to river deposition, meltwater streams and
low-energy waves. As sea levels rose at the end of the last glacial period wave action
pushed sediment onshore.
• In some places they beached at the base of former cliff lines, elsewhere they formed
bars and tombolos.
E.g = Chesil Beach Tombolo
• Formed during Flandrian Transgression, sediment carried into English Channel by
meltwater in Würm glacial period accumulated in Lyme Bay.
• Sea levels rose, and sediment carried northeast by south-westerly prevailing winds
and resultant waves.
• Moved 50 km and attached to Isle of Portland at one end and the mainland near
Abbotsbury at the other.
• Previously thought to have formed via spit extension.
• Future sea level rise will move shingle further northeast and a tombolo breach is
likely in storms.
Rias:
Submerged river valleys formed as sea levels rise.
• Lowest part of the rivers course and floodplains alongside may be flooded, but the
higher land of valley sides and upper course remains exposed.
• Exposed valley sides slowly sloping formed by fluvial processes. Underlain by alluvial
deposits in buried channels that were eroded by rivers.
• Further deposition occurred in interglacial periods when sea levels rose, and rivers
had less surplus energy for erosion.
E.g = South Devon, Salcombe
• Sand washed in from Atlantic Ocean
• Ria deep at Salcombe with a shallow entrance due to sand bar deposited in low
energy environment at Kingsbridge estuary mouth.
Fjords:
Submerged glacial valleys with steep sides and deep water (often over 1000m)
• U shaped cross section reflects original glacial valley. Lower erosion rated at seaward
end where ice is thinned in warmer conditions.
• Much straighter platforms as the glacier truncated and interlocking spurs. Due to
water depth in fjords during Flandrian Transgression, marine erosion rates remain
high.
• Today valley sides may also be affected by sub-aerial processes. This reduces
steepness of valley sides. Marine erosion is also likely to increase due to storm
conditions and larger waves.
E.g = South Island West Coast, New Zealand, Milford Sound
Infilling with sediments deposited by meltwater from Southern Alps glaciers.