Waterfall,Gorges & Interlocking Spurs

Question 1

How is a waterfall and gorge formed

Answer 1

1- A waterfall is created when there is a layer of hard rock above soft rock.

2- The hard rock is not eroded but the soft rock is using abrasion and hydraulic action.

3- The soft rock is carried away downstream leaving a large space behind.

4- As this continues, the drop gets bigger giving the water more force creating a deeper plunge pool.

5- The water starts to undercut, eroding the soft rock behind the waterfall creating an overhang , the hard rock becomes unstable.

6- Eventually the hard rock is undermined and unstable and collapses. The waterfall moves further upstream.

7- As it moves upstream the steep sides create a gorge.

Question 2

Interlocking spurs

Answer 2

Upper Course
-the river meets fingers of hard resistant rock called spurs the river channel doesn’t have enough energy to erode through these ridges so it flows around them instead.
-this erodes the soft rock inbetween