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Flashcards in Erosional Agents Deck (33):
1

What are the five erosional agents?

Running water, wind, waves, glaciers, mass wasting

2

What is the most important single agent of Erosion?

Running water

3

True or false: ALL erosional agents work in the same way.

True

4

What is the process erosional agents work in?

Erosion > Transportation > Deposition

5

What is fluvial erosion?

Higher velocity = higher potential erosion (flow velocity)

6

Flow velocity is the function of what two functions?

Slope gradient and discharge

7

What are two types of erosion?

Hydraulic action and abrasion

8

Hydraulic action?

"force of water can erode rocks" high velocity = high erosion

9

Abrasion?

Add sediments (clasts > rocks)
Chipping and grinning effect. (pot wholes)

10

What is slope gradient?

Steepness

11

What is discharge?

Volume > amount of water (cfs)

12

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.

13

What is fluvial transportation?

"channel flow"

14

A bed-load consists of what three functions?

Traction, sailtation, and suspended load.

15

Traction?

Rolling and sliding of large materials

16

Sailtation?

hopping and skipping of small materials

17

Suspended load?

Very fine particles suspended in flow, slow to settle, gives color to the water.

18

In most streams what is the largest portion of the bed-load?

Suspended load

19

What is a thalweg?

Area of the fastest current. Flows from outside curve to outside curve.

20

What do thalwegs create?

The erosion from the thalweg creates a cutbank on the outside curve.

21

What do cutbanks create?

Oxbows (meandering river)

22

Fluvial Deposition?

Erosion wears down landforms. deposition creates new landforms

23

Deposition occurs when?

when velocity is in adequate to transport the land

24

What two changes can cause a change in velocity?

Discharge and slope

25

Sediments are deposited and sorted how?

By size and weight

26

Landform of deposion is made up of what three functions?

Sand Bar (Point bar), Delta, Alluvial fan

27

What is a sand bar?

Develops on the inside curve.

28

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.

29

What is the largest delta in the world?

Indus river delta

30

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.

31

What is alluvial fan?

Alluvium = stream deposits.
Ephemeral stream (dry creek)
Short lived, but high velocity episodes

32

How does a alluvial fan develop?

In avid regions, mts./desert floor.
Develops where mts. canyons open onto the desert floor

33

What happens when alluvial fans over lap?

Causes a Bajada. ex.) Death Valley