Mass movement in evolution of cliffs - Coggle Diagram
Mass movement in evolution of cliffs
Sub Aerial process
Mechanical (Physical), Chemical and biological
Biological: Plant roots, cracks, joints. Halophytic plants - resistant to salt. birds making nests in the cliffs
Chemical - Carbonation - Dissolving of calcium - limestone. Hydrolysis - attacks felspar in granite. Weaken the structure of the rock. Oxidation of Iron
Mechanical - Freeze thaw (Frost Shatter) - Widens cracks (Water expands 9%) - Brakes of pieces of rock - provides tools for abrasion.
Salt Crystallisation - hot environments - Optimum temp 27 degrees
Exfoliation - Expanding and contracting
Heavy Rain - Increases weight - Permeable internal resistance - Landslides - Mudflows - Rotational Slumping - Unconsolidated Material such as glacial till
Hydraulic action - Sheer force of the water - Abrasion - rocks removing base of the cliff. Wave cut notch, removing base of the cliff, likely to result in cliff collapse, becomes unsupported - landslides and rock fall. Provides material for abrasion
Cavitation - Air forced into cracks - creates pressure in cracks and opens joints
Solution - links to chemical
Structure or rocks - Hard rocks dipping - away from sea- gentle profile. Hard rocks dipping towards the sea - steep profile - sheer face.
Permeability of rocks
Rock structure - Soft, porous top layer, overlying impermeable rock - Saturation - mudflows, slumping
Sot Rock - gentle profile - slumping
Conclusion: Without the material provided by mass movement the evolution of cliffs would be slow, limited to the effects of marine erosion. Incompetence of interrelationship between sub aerial processes from above with erosional processes from below.