UNIT 1C - River Landscapes in the UK Flashcards
What is Hydraulic action?
force of water breaks rock particles away from the river
What is abrasion?
eroded rocks are picked up and rubbed against the river, wearing it away (most erosion)
What is attrition?
eroded rocks picked up by the river smash into each other and break into smaller fragments, edges are rounded off, decrease slowly the closer it gets to the mouth
What is solution?
river water dissolves some rock ( chalk and limestone)
What is traction?
large particle boulders are pushed along river bed by force of water
What is suspension?
small particles like silt and clay are carried along
What is saltation?
pebble-sized particles bounce along the river bed by force of water
What is solution?
soluble materials dissolve in water and are carried along
What does the long profile of a river show you?
the gradient (steepness) changes over its course
Features of the upper course?
steep, v-shaped valley, steep sides narrow, shallow channel
Features of the middle course?
gently sloping valley sides, wider, deeper channel/ medium
Features of the lower course?
gentle, very wide, almost flat, valley very wide, deep channel
What is vertical erosion?
deepens river channel, making it v-shaped. Dominant in upper course, high turbulence causes rough, angular particles scraped along bed, intense downward erosion
What is lateral erosion?
widens the river valley (and channel) during formation of meanders, dominant in middle and lower course
What is deposition?
is when a river drops the eroded material its transporting when it slows down
Where are waterfalls and gorges found?
in the upper course
How are waterfalls formed?
where a river flows over hard rock and followed by soft, softer rock is eroded ( hydraulic action and abrasion) creating a step in the river, as water goes over it, it erodes more and more. A steep drop is eventually created, hard rock is eventually undercut by erosion, it becomes unsupported and collapses, this is repeated and waterfall reseeds more and more
What is interlocking spurs?
the upper course of the river, eroding downwards, it cant erode laterally so they wind round the high hillsides, they interlock with each other like a zip