48 terms

Unit Five: Test Five - Erosion

What is erosion?
the process that transports Earth's weathered materials from one place to another.
Name the three erosion types in Wind erosion.
Creep, Saltation, and Suspension
What is loess?
A light colored dust that retains water well and forms the basis of great soil that was transported by wind.
Describe Saltation.
Larger particles are pushed and bounced along the ground. This accounts for most wind transport of sand.
Name and describe the four main types of sand dunes.
Barchan dune - Most common, crescent shaped, constant wind
Parabolic dune - Always in moist environment, requires vegetation to anchor ends.
Transverse dune - Long, asymmetrical, form at right angles to the wind direction., abundant supply of sand.
Lateral (Longitudinal) dune - Abundant sand, strong cross winds from at least two directions, sand in long lines or ridges, straight or slightly wavy.
Describe how rivers erode the land.
Water moves faster on the inside of outside curves - increases erosion. Water moves slower on inside curves - greater deposition.
Which part of the river has faster flowing water and also more erosion?
The outside curve of a meander.
Which part of the river has slower moving water and also more deposition?
The inside curve of a meander
Describe how rivers mature.
Over time, rivers become wider and deeper.
What is an oxbow lake?
A lake formed when the river bypasses its wide meanders.
How is an oxbow lake formed?
An oxbow lake is formed when a meander in the river is eroded enough that it meets and then bypasses the curve.
What is river delta?
A river delta is where a stream or river empties into a larger body of water.
What is an alluvial fan?
An alluvial fan forms where streams descend steep slopes onto a flat plain.
What is the difference between a delta and an alluvial fan?
A delta is where the river empties into a body of water and an alluvial fan is where the river empties onto flat land.
What is stream flow velocity?
how fast water in a river is moving.
What does sediment transport in a river depend on?
It depends on the velocity of the water in the stream.
- Slower moving water holds less and smaller sediments.
- Faster moving water transports more and bigger sediments and erodes the river channel more quickly.
How does a river deposit its load?
As water slows down, the largest particles or sediment is dropped first.

So the further away from the source, the smaller and more rounded the particles are.
What is mass wasting?
Mass wasting is the movement of large amounts of material downhill under gravity.
What is the biggest force responsible for mass wasting?
Name five main types of mass wasting.
Slump, solifluction, creep, rock fall, and mudslide
Which two types of mass wasting require conditions to be wet?
solifluction and mudslides
Which two types of mass wasting require conditions to be dry?
creep and rock fall
Which two types of mass wasting happen slowly over time and cannot be directly observed?
Creep (dry conditions) and solifluction (cold, wet conditions)
What is the angle of repose?
The Angle of Repose is the steepest angle at which a pile of grains remains stable.
Name two main factors that can affect the angle of repose.
the size of the particle and the amount of water in between the grain sizes
How does the size of particle affect the angle of repose?
The smaller the particle, the smaller the angle of repose.
How does water affect the angle of repose?
SMALL amounts can increase stability.
Excessive water leads to slope failure because friction is reduced.
Which agent of erosion (transport) has the lowest energy?
Which agent of transport has a poor degree of sorting?
Glacial Ice
Rank the agents of erosion (transport) on their ability to sort particles into similar sizes.
Worst to Best: Glacial Ice, Flowing Water, Wind
Which agent of erosion (transport) has the worst sorted particles (meaning it has all sizes)?
Glacial Ice
Which rock type is made from deposits of sediments from rivers, glacial ice, and wind?
Sedimentary rocks
These rocks are clastic (made of large rock particles) that can be angular or smooth
Breccia (angular) and Conglomerate (smooth)
Which sedimentary rock is formed from fine particles like clay?
Which sedimentary rock is rough wit a gritty feel and tends to be porous?
Which type of sedimentary rock is formed when water evaporates and leaves behind minerals?
Chemical sedimentary rocks (like halite and gypsum)
Which type of sedimentary rock is formed when organic matter like shells, plant material or bones accumulate?
Organic sedimentary rocks (like limestone and coal).
What does the degree of sorting and size of sediment tell you?
It tells you about the environment rocks formed in.
Put these words in correct order to explain how sedimentary rocks are formed: Cementation, Compaction, Deposition, Erosion, Weathering
Weathering, Erosion, Deposition, Compaction, Cementation
What is a glacier?
A glacier is a large mass of moving ice.
What are glaciers made of?
Glaciers are made up of fallen snow that, over many years, compresses into large, thickened, ice masses.
What causes a glacier to grow?
Snow added greater than snow melted = glacier grows.
What causes a glacier to move?
A glacier begins to move downslope and outward under its own weight.
What is Glacial Drift?
Sediment carried and deposited by glaciers. Can be TILL (carried by ice) or OUTWASH (carried by water).
What is a drumlin?
A drumlin is a sediment mound.
What is an esker?
An esker is a long, winding ridge of gravel and sand - like a raised roadway.
What is a kettle?
A kettle is a depression - can form lakes.
What is a moraine?
A moraine is a ridge of deposits - like a wall. It can be at the leading edge of glacier.

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