How are landforms created by rivers? Flashcards
Where do waterfalls occur?
Where hard rock overlays soft rock in the upper course
How does a waterfall retreat over time?
- Softrock is undercut by erosion (hydraulic action/abrasion) A deep plunge pool develops where soft rick used to be.
- The overhanging hard rock collapses and the waterfall retreats upstream to create a gorge
What landform is left as a waterfall retreats upstream and why?
A steep sided cutting is left as the waterfall moves back. This is called a gorge
Where does a river flow faster and slower?
The river flows faster on the outside bend and slower on the inner bend.
What occurs on the inner and outer bend of a river?
Sediment is deposited on the inner bend creating a slip off slope. Because water flows faster on the outer bend it is eroded and a river cliff begins to form.
How does a meander form?
The outer bend is eroded because of the faster flow of water and creates a bend and the inner bend creates a slip off slope because sediment is deposited there.
How is an oxbow lake formed?
A meander will become so sharp that water will erode a faster path straight along instead of round the corner. It will break through and water will begin to flow straight. Sediment will be deposited to create an oxbow lake.
