Flashcards in Erosional Agents Deck (33):
What are the five erosional agents?
Running water, wind, waves, glaciers, mass wasting
What is the most important single agent of Erosion?
True or false: ALL erosional agents work in the same way.
What is the process erosional agents work in?
Erosion > Transportation > Deposition
What is fluvial erosion?
Higher velocity = higher potential erosion (flow velocity)
Flow velocity is the function of what two functions?
Slope gradient and discharge
What are two types of erosion?
Hydraulic action and abrasion
"force of water can erode rocks" high velocity = high erosion
Add sediments (clasts > rocks)
Chipping and grinning effect. (pot wholes)
What is slope gradient?
What is discharge?
Volume > amount of water (cfs)
What is the chipping and grinning effect?
Turns rocks into rounded river rocks over a long period of time after chipping and grinning against others rock flowing down a body of water (river). Creates sculpted canyons.
What is fluvial transportation?
A bed-load consists of what three functions?
Traction, sailtation, and suspended load.
Rolling and sliding of large materials
hopping and skipping of small materials
Very fine particles suspended in flow, slow to settle, gives color to the water.
In most streams what is the largest portion of the bed-load?
What is a thalweg?
Area of the fastest current. Flows from outside curve to outside curve.
What do thalwegs create?
The erosion from the thalweg creates a cutbank on the outside curve.
What do cutbanks create?
Oxbows (meandering river)
Erosion wears down landforms. deposition creates new landforms
Deposition occurs when?
when velocity is in adequate to transport the land
What two changes can cause a change in velocity?
Discharge and slope
Sediments are deposited and sorted how?
By size and weight
Landform of deposion is made up of what three functions?
Sand Bar (Point bar), Delta, Alluvial fan
What is a sand bar?
Develops on the inside curve.
What is a delta?
Perennial river year around thus always there. Forms at the mouth of a river where the river empties into the ocean.
What is the largest delta in the world?
Indus river delta
What does it mean to be delta-less? and what would be an example?
A river with no connection to the ocean (has not delta) Amazon river in an example of this.
What is alluvial fan?
Alluvium = stream deposits.
Ephemeral stream (dry creek)
Short lived, but high velocity episodes
How does a alluvial fan develop?
In avid regions, mts./desert floor.
Develops where mts. canyons open onto the desert floor