Holderness Coast Case Study

Holderness Coast Case Study

1. influence of climate on landforms/ landscape

   • freeze-thaw weathering particularly in the winter due to temperatures fluctuating above and below 0 expands cracks and weaknesses in chalk (resistant)
   • stormy conditions during the winter increase rates of erosion due to destructive waves causing hydraulic action and abrasion
   • Warmer temperatures during spring and summer cause vegetation growth increasing biological weathering

2. influence of geomorphic processes on landforms: spit

   • spurn head is narrow sand spit on the Yorkshire coast - extends across the Humber Estuary by 3 miles
   • made up of the material that has been transported along the Holderness Coast - includes sand, sediment and shingle
   • up the coast - 1. long shore drift takes place in a southerly direction
     • 2. where the coast line changes direction long shore drift continues and deposits sediment starting to form a spit
       • 3. As the spit has grown there have been a couple of hooked ends caused by a change in wind direction
         • 4. The protected waters behind the spit have trapped sediment coming down the river and a salt marsh ecosystem has developed there
   • LONG SHORE DRIFT
   • Spurn Head

3. influence of geology on landforms

   • Holderness is a discordant coastline - rocks are perpendicular to the sea, causing different rates of erosion
   • the geology runs in bands - Flamborough (north) = chalk - south = boulder clay or till (laid down in the last ice age)
     • Because the clay is weak (soft rock), it erodes more rapidly than the more resistant chalk (hard rock)
       • processes of erosion on the clay - hydraulic action, freeze thaw, abrasion, solution and carbonation
         • this has left a bay where the clay is and a headland jutting out to sea at Flamborough head
           • The incredibly weak nature of the clay means that it erodes faster than the chalk
           • Flamborough head is composed of chalk - sedimentary rock - layers are opened up by hydraulic action forming caves

4. influence of geomorphic processes on landforms - cave, arch, stack, stump

   • Cracks at the base of the chalk headland widened by hydraulic action and abrasion
     • Cracks further widened by chemical and mechanical weathering
       • Over time cracks widen and develop as wave-cut notches. Abrasion and hydraulic action will deepen the notch to form caves
         • Wave refraction concentrates destructive wave energy on the sides of the headland widening an deepening the wave. Eventually breaks through headland to form and arch
           • Roof of arch weakened by biological and mechanical weathering causing it to become unstable and it collapses under its own weight, leaving a pillar of rock called a stack
             • The stack is further eroded at its base creating new wave-cut notches. Weathering processes continue to weaken the stack from above
               • Eventually, the exposed stack will collapse to form a stump, which is only visible at low tide

5. headlands and bays - flamborough head and selwicks bay

   • 1. Coastline faces the wave attack with DISCORDANT beds of sediment
   • 2. Wave attack causes hydraulic action and abrasion which causes the cliff to retreat
   • 3. Less resistant rocks are eroded at a faster rate to create bays, more rocks stick out to sea as headlands
   • 4. During calm periods the sheltered bays allow deposition of beaches