Erosional landforms

• Erosional landforms


  the erosional features are normally found in the upper course of the river.
• Waterfall


  A sudden drop along the river course. Forms when there are horizontal bands of resistant rock positioned over exposed, less resistant rock.
• 1. the soft rock is eroded quicker than the hard rock, this creates a step.
  2. as erosion continues, hard rock is undercut causing an overhang
  3. abrasion and hydraulic action erode to create a plunge pool
  4. this gets bigger, increasing in size until it is no longer supported and collapses.
  5. continues and waterfall retreats upstream.
  6. steep sided valley is left (gorge)

  
• interlocking spurs


  in the upper course there is more vertical erosion. The river cuts down into the valley. If there are areas of hard rock (which is harder to erode) the river will bend around it.