COASTS AS AN OPEN SYSTEM

Slide 1

• Coasts can be classed in many ways:
• -Erosional/depositional
• -Sediment type - clastic (fragments like sand or shingle) or muddy
• -Submergent or emergent - linked to isostatic / eustatic change
• -Tectonic setting
• -Process based - tide/wind etc?

Slide 2

• Dynamic Equilibrium - when inputs balance outputs - overall system does not change
• Positive Feedback - harmful, detrimental to coastal systems. an action leads to something becoming more than it was before, e.g global temp rise = increase ocean temps = warm water less able to dissolve co2 = co2 released by warmer oceans = co2 into atmosphere = more co2 as greenhouse gas
• Negative Feedback - equilibrium, action leads to something becoming less than it was before. e.g sediment eroded, deposited, forming a bar, waves break earlier, reduces erosion, when storm calms normal wave conditions bring sediment back to beach

Slide 3

• Inputs - Marine = waves,tides . Land = rock type. Atmospheric = weather climate, solar energy. People = human activities
• Process = weathering and mass movement. Erosion. Transportation.
• Output = landforms. sediment. shape of coastline. Depositional landforms

LANDFORMS

• French, 1997 - Order of energy from highest to low: WAVE DOMINATED, TIDE DOMINATED, WIND DOMINATED
• Wave --> Shore platforms, cliffs, beaches, spits
• Tide --> Mudflats, sandflaTS, salt marshes, mangroves, deltas
• Wind --> spits, sand dunes