2. The Holderness Coast is one of Europe's
fastest eroding coastlines. The average
annual rate of erosion is around 2 metres
per year. This is around 2 million tonnes of
material every year. Under lying the
Holderness Coast is bedrock made up of
Cretaceous Chalk. However, in most place
this is covered by glacial till deposited over
18,000 years ago. It is this soft boulder
clay that is being rapidly eroded.
7. Spurn Point provides evidence of longshore
drift on the Holderness Coast. It is an
excellent example of a spit. Around 3% of
the material eroded from the Holderness
Coast is deposited here each year.
9. 9
Landslips: also known as rotational slumps, are occasional
rapid movements of a mass of earth or rock dropping down
along a concave plane. Water percolating through sandstone
gets into the clay beneath, saturating it. With the weight of the
rock above forcing down on it the clay moves seawards as a
mud flow. With the clay moving sideways the sandstone above
slumps down. Undercutting of a steep slope by the sea
weakens the rock above, making a slump more likely.
10. 10
Rockfall: rapid, free-fall of rock from a steep cliff face due to
gravity. This is made worse by freeze-thaw action loosening
the rock - water enters the joint (vertical crack), freezes and
expands, breaking up the rock. A scree slope of fallen rock is
formed at the bottom of the cliff. It is also possible for free
falls to occur in very dry conditions – for example clay cracks
as it dries out and then crumbles easily
11. 11
Mudflow: occurs on steep slopes over 10°. It's a
rapid sudden movement which occurs after periods
of heavy rain. When there is not enough vegetation
to hold it in place, saturated clay flows out of the cliff
face, almost like a river of mud.
