Changing Landscapes Of The Uk - Rivers Flashcards
Mass movement
The movement of rocks and soil downslope due to gravity
Soil creep
Individual particles of soil move slowly down a slope
Sliding
Material moving rapidly down a slope in one go e.g landslide
Flows
Masses of rocks moving downslope as they mix with water and flow like a liquid
Deposition
When a river no longer has enough energy to carry its load (material) so drops the material the process of material being dropped by the river
Transportation
A river picks up and carries material as it flows downstream
Hydraulic action
Air is forced into cracks in rocks in the river,forcing rocks apart
Attrition
Rocks and pebbles in the river crash into each other, causing the rocks to become smoother and smaller
Abrasion
Rocks in the river crash into river banks and are dragged along the river bed causing erosion like sand paper
Solution
Acidity in the river dissolves soft rock
Weathering
The breakdown of rocks at or near the surface by natural processes (usually on the river valley sides)
Biological weathering
Living things, such as the roots of trees,breaking soil and rocks apart
Chemical weathering
Rainfall is slightly acidic therefore it dissolves softer rocks
Mechanical weathering (Freeze-thaw)
Water that’s has seeped into the cracks of rocks as it freezes it expands in volume by 9% in volume cracking and forcing the rock apart it is repeated until the rock splits in two
Saltation
Small rocks are bounced along the river bed
Suspension
Small sediments are carried in the river (held up) downstream
Solution (transportation)
Small grains of sediment are dissolved and carried down the river downstream
Traction
Large boulders being rolled along the river bed downstream
point bars
Point bars are made up of the deposited material that accumulates on the inside bend of a river meander.
They are crescent-shaped, are very gently sloping and found below the slip-off slope.
They are made of alluvium.
levees
Levees are piles of sediment that form at the side of river channels after repeated flooding.
mouth
the end point of a river where it meets the sea or ocean
levee
a raised bank of sediment along the side of a river
waterfall
a flow of water falling from a height into a plunge pool
source
the starting point of a river