Interlocking spurs:
● Interlocking spurs = projections of high land
that alternate from either side of valley and
project into the valley floor
○ Formed by fluvial erosion
○ Found in upper course → rocks are
hard
→ Characteristics:
● Steep gradient
● Convex slopes
● Project from alternate sides of valley
● Separated by narrow valley floor , taken up by
river
● Sometimes wooded
● May have scree slopes
→ Formation:
● Stage 1
○ Upper course → river’s water volume and discharge are low
○ River uses most of energy overcoming friction with channel
○ Energy left over is used by hydraulic action to deepen channel
● Stage 2
○ Freeze-thaw weathering gradually broadens out valley
○ Gives valley steep V-shaped cross profile
○ Repeated weathering weakens rock → breaks as fragments and river carries it away
● Stage 3
○ Winding path taken by river due to hard rock creates spurs
○ River takes easiest route over the land
○ Results in projections of high land = interlocking spurs
Rapids:
● Rapids = fast-flowing , turbulent sections of a river where the river bed
has a relatively steep gradient
○ Ability of a river to erode depends on:
■ River’s energy
■ Hardness of bedrock
● Vertical bedding = alternate bands of hard and soft rock across the
channel → causes differential erosion
○ Soft rock is more easily eroded than hard rock
○ Makes river bed uneven and river’s flow becomes turbulent
○ Results in white water and sections of typical rapids
→ Characteristics:
● Turbulent flow of water
● White water
● Uneven river bed
● Steep gradient
