Landforms in lower course Flashcards
(21 cards)
What characterizes the lower course of a river?
High volume and large discharge
The river channel is deep and wide, and the surrounding landscape is flat.
What happens to a river as it reaches the end of its journey?
Energy levels are low and deposition takes place.
Where are deltas typically found?
At the mouth of large rivers.
What is a delta?
A landform created when a river deposits its material faster than the sea can remove it.
What are the three main types of delta?
- Arcuate or fan-shaped
- Cuspate
- Bird’s foot
Describe an arcuate delta.
Land around the river mouth arches out into the sea, creating a fan effect.
Describe a cuspate delta.
Land around the mouth of the river juts out arrow-like into the sea.
Describe a bird’s foot delta.
The river splits and each part juts out into the sea, resembling a bird’s foot.
What is the role of waves in the formation of a cuspate delta?
Waves carry sediments away from the coast.
What should a labeled diagram of a delta include?
- Distributaries
- Shape of delta
- Flatland
- Sea
- Fertile soil
What type of load does the lower course of a slow-moving river carry?
Fine silt as suspension load.
What happens to the river’s speed as it enters the sea?
The speed reduces and deposition takes place.
What creates the bottom-set beds and top-set beds during deposition?
The heaviest sediment is dropped first, and the lightest last.
What process helps the deposition of fine sediment in a delta?
Flocculation.
What happens to fine clay particles during flocculation?
They stick together and become heavier, dropping to the sea bed.
How does sediment deposition affect the river channel over time?
The river channel becomes blocked by silt, leading to more flooding.
What do distributaries do as the river finds its way to the sea?
They wind around the islands created by deposited sediment.
What emerges as more sediment is deposited in the delta?
Islands of dry land.
imbetween distributaries
How does vegetation relate to delta formation?
Vegetation grows on the islands of dry land that emerge.
True or False: The delta is a static formation.
False.
What continually affects the delta over time?
Currents and floods.
