erosional landforms pg

Question 1

how do v shape valleys form

Answer 1

sediment transported by the river is scraped along bed and banks causing both lateral and vertical erosion by abrasion
valley sides become weakened by weathering and loose soil and rocks will slump down the sides into river
continuing processes cause valley sides to become steeper and have an increasing v shape

Question 2

formation of waterfalls / gorges

Answer 2

step or notch forms in softer rock creating river rapid
height of drop increases until eventually a waterfall forms
less resistant rock is undercut leaving harder rock unsupported
overhanging harder rock breaks off hits base
abrasion created plunge pool
process repeats over long time a gorge may form

Question 3

ox bow lake formation

Answer 3

erosion causes bends to move closer together to create swan neck meander
during flood high energy water breaches meanders neck
river flows in straighter and faster course
deposits fill in meander bend
meander becomes cut off from river forming ox bow lake