upland features Flashcards
what are examples of upland features
V-shaped valleys, interlocking spurs and waterfalls.
stages of upland features
As the river moves through the upper course, it cuts downwards. The gradient here is steep and the river channel is narrow. Vertical erosion in this highland part of the river helps to create steep-sided V-shaped valleys, interlocking spurs, rapids, waterfalls and gorges
what is a spur
A spur is land jutting out causing a river to meander.
how is an interlocking spur formed
As the river erodes the landscape in the upper course, it winds and bends to avoid areas of hard rock. This createsinterlocking spurs, which look a bit like the interlocking parts of a zip.
what are the stages of formation of a V shaped valley
- Water cuts downwards – this is called vertical erosion.
- Wind and rain loosens rocks on the valley sides through weathering
- The sides collapse and the material slides into the river
- A V-shaped valley is formed
what is stage 1 for the formation of a waterfall
A waterfall will form where there is water flowing over a band of hard rock (e.g granite) overlying softer rock (e.g sandstone)
Due to differential erosion, the soft rock will erode faster than the hard rock.
what is stage 2 for the formation of a waterfall
Over time, erosional processes such as hydraulic action and abrasion will dominate the soft rock and a plunge pool will be created.
what is stage 3 for the formation of a waterfall
The softer rock is further eroded and creates an undercut. This causes an overhang of the hard rock to form.
Eventually the hard rock overhang collapses as it’s weight is unsupported.
what is the final stage for the formation of a waterfall
This process will repeat continually with the soft rock undercut and hard rock collapsing. This will cause the waterfall to slowly retreats (moves back) upstream creating a steep sided gorge.
what is the formation of a gorge
As a waterfall retreats upstream it leaves a gorge. Every time a section of overhanging rock breaks away the gorge grow larger.