River Test. EQ4 & EQ5 Flashcards
(20 cards)
Hydraulic action
Power of the waves force water into cracks and increases the pressure and craft gets bigger and will break eventually
Abrasion
Rocks are picked up by the waves and smashed or rubbed against cliffs which will wear the rock away
Solution
When the scene becomes water acidic (caused by vegetation) which will dissolve the rocks such as chalk/limestone
Attrition
Rocks in the way with a smashed together and break into smaller rocks and become smoother
Formation of a meander
1)river erodes on the outside of the bend where the current flows strongest and fastest.
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2) The inside of the bend where the water flows slowest, deposits it’s load (rocks/sediments) forming a slip off slope.
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3) overtime the Deposition and erosion continue, changing the course of the river.
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4) when the river meander reaches the sides of the valley,it erodes them, widening the valley floor and floodplain
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5) overtime the meander will repeat the process until only a narrow neck of land is left.
Oxbow lake formation
1). Erosion through hydraulic action and abrasion causes the bends to get closer together.
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2) it will erode until there is a small bit of land left between the band (this is called the neck)
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3) The river breaks through usually during the flood.
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4) Deposition eventually cuts off the meander, which will then form an oxbow lake. (Eventually the oxbow lake will dry out)
Drainage basin
1) source – where the river begins
2) tributary – small river/stream that joins a bigger river
3) confluence – a point where to River meet
4) watershed - area of highland forming the edge of the river basin
5) Mouth - where river meets the sea.
Mass movement
Process of rock material moving down due to gravity
Slumping
Permeable sand let rain through and impermeable clay won’t let water through. waves then attack impermeable clay and will slide downwards.
Transportations
1) traction – stones roll along the river bed
2) Saltation - little particles bounce along the riverbed.
3) suspension - the water flow carries tiny particles
4) solution - the river water dissolves some minerals.
Types of weathering
Freeze thaw – water gets into cracks and freezes overnight and melted during the day and years later the crack will get bigger and the crack becomes unstable and breaks.
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Chemical – water hits land and rocks fall off caused by acidic rain because of carbon dioxide in the air
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Biological - when a plant grows inside of the crack of a rock and the roots of the plant will put pressure on the rock and will weaken it.
