Davisian cycle

The Davisian cycle of land form evolution also referred to as t e geomorphic cycle or Erosional cycle was proposed by William Morris Davis

• He observed that the physical landscape undergoes modification as a result of the nature the agencies in an orderly progressive sequence or stages- e.g. youthful, mature and old / senile stage.
• Slopes evolve towards a level surface that returns to their point of origin.
• The cycle begins with uplift leading to building of highlands/uplands due to earth movements or orogenic processes.
• The uplift bas to be simple and fast/ rapid enough that it does fast/rapid enough that it does not experience significant erosion during this phase.
• The uplifted land then undergoes the cycle of erosion/ down cutting by rivers, glaciers, wind and the weathering processes.
• Rivers at this stage (i.e. Youthful) deepen their valleys through vertical erosion, flow at high speed forming V-shaped valleys.
• As the process continues the relief decreases, slopes and valleys become more gentle.
• Lateral erosion becomes more dominant and valleys become relatively broadened (U-shaped) due to reduced gradient This is the mature stage of slope development
• With continued erosion and deposition the relief later becomes relatively smooth and flood plains begin to develop the land form evolution reaches the old/ senile stage.
• Rivers then deposit the eroded materials from the youthful and mature stages.
• Deposition results into meandering as the relief becomes more gentle/ flatter.
• Lowland finally develops and Davis calls this a peneplain or a level surface.
• When the peneplain stage is achieved uplift occurs so that the cycle starts again, hence a return to a level or point of origin.
• The Davisian cycle therefore clearly points out the value of structure, process and time/ stage in land form