HOLDERNESS

WHAT PHYSICAL FACTORS ARE AT WORK ALONG THE COASTLINE
1. GEOLOGY
  1. ROCK TYPE
    1. CHALK
      1. More resistant chalk has survived large scale eroision - FLANBOROUGH HEAD
        FLANBOROUGH HEAD
        The sea is eroding and undercutting the base of the cliffs = frequent rockfalls. High tide line is clearly shown by the dark staning at teh foot of the cliff
        Within the headland joints (vertical cracks) form which run through the chalk - FAULTS. They are readily exploited by the process of weathering and erosion forming narrow clefts in the coastline --> major faultline has been exploited to form SELWICKS BAY
      2. chalk forms - stacks, stumps, arches, headlands and wavecut platforms
      3. Stretches from Lincolnshire Wolds south to Flanborough Head
      4. Distinctive lithology - layers of chalk are clearly visible
      5. the chalk is part of the pre glacial coastline
        The scandinavian ice sheets deposited the boulder clay
    2. BOLDER CLAY (moraine)
      1. differential rate of erosion and much more easily eroded than the chalk
      2. 100 villages lost since Roman times
      3. Retreat has formed the sweeping bay of Holderness
      4. sediment carried and dumped by ice sheets originating in scandinavia
      5. forms - slumping, bays and mass movement
2. WEATHER
  1. winterstorms produce stronger waves and higher sea levels (surge). In addition the rain they bring intensifies land-based (sub aerial) processes. The saturated clay cliffs suffer increased runoff leading to slumping and other forms of mass movement.
3. WAVES
  1. TIDES
    1. Tides and the lower energy environment of the Humer estuary allow sediment to collect forming a spit, mudflats and sand dunes near to spurn head
      1. SPURN HEAD
  2. SEA LEVEL RISE
    1. FETCH - greatest fetch from north east
      1. greatest fetch - when the wind is blowingfrom teh nort east it can drive powerful waves towards holderness coast. Ocassionally, areas of extremely low pressure move down teh north sea, funnelling water and creating storm surges several metres high
      2. STORM SURGES
        INCREASED EROSION - These low frequency high magnitude events can lead to significant erosion - FLOODING - in 1953 300 people lost their lives along the east coastof england during such an event. As a result longshore drift changes to north to south
    2. Sea levels rose at the end of the last glacial period, the north sea took shape and started to erode the thick till deposits to help form the present day cliffs
  3. REFRACTION - wave refraction further acting concentrates waves on headlands allowing caves to develop progressively into arches, stacks and stmps
  4. DESTRUCTIVE - destructive waves erode the beaches and attack the foot of teh cliffs, removing the clay in suspension
  5. LONGSHORE DRIFT - longshore drift then carries the material southward, the revailing wind is NORTH EAST
  6. the dominant waves are from the north east which is also the direction of the largest fetch. Destructive waves erode the beaches and attack the foot of the cliffs, removing the clay in suspension. Longshore drift then carries this material southward.
WHAT FEATURES AND PROCESSES MAKE THIS COASTLINE SO DISTINCTIVE?
1. the 6km spit at Spurn Point
2. retreating clay cliffs of the Holderness Bay
3. the impressive chalk headland and cliffs near Flamborough
  1. THE HOLDERNESS CLIFFS
WHAT HUMAN FACTORS PLAY A PART ALONG THIS COAST?
1. THE PRESSENCE OF PEOPLE ALONG THE COAST - turns physical processes into hazards and threatens life and property. Increasing population levels due to retirement and teh development of leisure and holiday facilities have occured around Bridlington and Hornsea. Caravan parks are a particular feature of this area. The risks from erosion have been much publicised at Easington where the gas terminal has been under threat
2. INTEFERING WITH NATURAL PROCESSES - such as longshre drift or implementing unsuitable deffence strategies can have adverse effects. The downdrift impacts of groynes at Hornsea, Mapppleton and Withersea mean that sediment is being prevented from building beaches elsewhere. Rapid erosion rates at sites like great cowed maybe due to this sediment starvation effect.

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	Erstellt von Jess Peachey vor etwa 8 Jahre