Landforms in the upper course Flashcards
What shape does a valley formed by a river typically take?
V-shaped valley
A V-shaped valley is created by the vertical erosion of a river.
What are interlocking spurs?
Protruding hillsides the river winds around
Interlocking spurs are formed when the river does not have enough energy to erode laterally.
How does a river erode the landscape vertically?
By hydraulic action and corrasion
Hydraulic action involves the force of water breaking down rocks, while corrasion involves the load eroding the river bed and banks.
What is hydraulic action?
The force of water breaking down rocks
It occurs when water enters small cracks and exerts pressure, causing erosion.
What is corrasion?
Erosion caused by the load hitting the river bed and banks
This process aids in the erosion of the landscape as materials collide with the river banks.
What process exposes valley sides to freeze-thaw weathering?
Vertical erosion by the river
Freeze-thaw weathering loosens rocks which can fall into the river, contributing to erosion.
What happens to rocks that fall into the river?
They assist in the process of corrasion
Fallen rocks contribute to further erosion of the river bed and banks.
What creates a waterfall?
Differential erosion of softer and harder rocks
The softer rock erodes quicker, creating a step or ledge that leads to a waterfall.
What are the three main ways a river erodes rocks?
Hydraulic action, corrasion, corrosion
Each method contributes differently to the erosion process.
What is a plunge pool?
A deep pool formed below a waterfall
It is deepened by the swirling rocks and increased hydraulic action during high discharge.
What happens to the overhang of harder rock at a waterfall?
It becomes unsupported and collapses
This process contributes to the formation of a plunge pool and the upstream movement of the waterfall.
What are potholes in a river?
Depressions formed in the river bed due to differential erosion
They usually start when a weakness or crack is exposed in the solid rock.
Fill in the blank: The process by which the river water dissolves minerals from the rocks is called _______.
corrosion
True or False: Interlocking spurs are formed because the river has enough energy to erode laterally.
False
The river does not have enough energy to erode laterally, leading to the formation of interlocking spurs.
What happens during times of high discharge at a waterfall?
Hydraulic action is most powerful
This results in further deepening of the plunge pool.
