66 terms

Unit 8: Erosion and Depostion

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Terms in this set (...)

Erosion
A process that wears away surface materials and moves them from one place to another
Deposition
When sediments are dropped by erosional forces moving them
1. Gravity 2. Wind 3. Water 4. Glaciers 5. Human Activity
Major causes of erosion (5)
Mass Movement/ Mass Wasting
Any type of erosion that happens as gravity moves materials downslope
Slump
When a mass of material slips down along a curved surface
Creep
Occurs when sediments slowly shift their positions downhill
Rockfalls
Happen when blocks of rock break loose from a steap slope and tumble through the air. They happen fast
Rock Slides
Occur when layers of rock slip downslope suddenly. They happen fast
Mudflows
A thick mixture of sediments and water flowing down slope
Landslides
Mass movements that is usually a combination of a Slump, Creep, Rockfall, Rock Slide, and a mudflow
Glacier
A large mass of ice and snow moving on land under its own weight
1. Snow remains on the ground year round and piles up 2. Snow accumulates and lower layers are compressed into ice 3. Ice becomes plastic-like (Soquid) because of increasing pressure 4. The mass slowly begins to flow
What is the formation of a glacier
Plucking
Peices of broken rock that are lifted away from the bedrock by glacial ice
Grooves
Deep, long, parallel scars on rocks
Straitions
Shallow grooves
Glacial Movement
Grooves and Striations are always parallel to the direction of what
Till
A mixture of sediment ranging from clay to boulder size, left behind by a retreating glacier
Moraine
Till deposite at the leading edge or along the sides of the glacier when its not moving forward
Outwash
Material deposited by th meltwater from a glacier, most often beyond the end of a glacier (Often forms a fan-shape)
Eskers
A glacial deposit that looks like a long winding ridge
Kettle
A shallow body of water that occurs as a result of blocks of ice being burried by glacial outwash
Drumlin
An elongated hill in the shape of a half buried egg
Kame
An irregularly shaped hill or mound
Continental Glaciers
Huge, Dome-shaped mases of ice and snow, Cover 10% of Earth, and Form at high latitude
Valley/Alpine Glaciers
Form at high altitude
Cirque
Bowl-shaped basin eroded by a valley glacier
Arete
A long ridge that forms between two adjacent valley glaciers
Horn
A sharp peak that forms when valley glaciers erode a mountain from several directions
U-Shaped Valley
A glacially eroded valley
Hanging Valley
A triditary glacial valley whose mouth is high above the floor of the mountain
Deflation
Blows across loose sediment, removing small particles such as silt and sand
Abrasion
When windblown sediment strikes rock, the surface surface of the rock gets stripped and worn away
Sandstorm
When the wind blows forcefully, in the sandy parts of desserts, sand grains rise in the air
Dust Storm
Blows topsoil from feilds, overgazed feilds and places where vegitation has dispeared, and is usually bigger than sandstorms
Loess
Wind deposits of tightly packed fine grained sediments
Dune
A mound of sediments drifted by wind, and is common in desserts regions or along the shores of oceans, seas, and lakes
Barchan
A cresent shaped dune
Transverse
Long dunes perpendicular to the wind direction
Star
Form pointed structures in areas where the wind blows from many directions
Sheet Erosion
When water flows in thin broad sheets and carries away sediments
Rill Erosion
When a grooves or small ditch forms on the side of a slope because of running water
Gully Erosion
When a rill channel becomes broader and deeper
Channel
A groove created by water moving down the same path over and over
Stream Erosion
When water continues to flow in a low place, picking up sediments from the bottom and side of the channel causing the channel to become deeper and wider
Load
The sediments being eroded by a stream
Suspended Load
Light weight sediments being carried by a stream
Bed Load
Heavier sediments that roll along the bottom of the stream channel
Drainage Basin
The area of land from which a stream or river collects runoff
Dam
A soil, sand, or concrete structure used to control water flow downstream
Levee
A mound of Earth built along the sides of a river
1) Young Stream 2) Mature Stream 3) Old Stream
What are the three stages of Stream Development
Meander
A broad arc or band
Flood Plain
A broad, flat valley floor formed by a meandering stream
Oxbox Lake
A meander that had been cut off from the main river as it changes cource
Delta
A triangular area of fertile land, extending into the ocean where rivers empty into large bodies of water
Ocean Shorline
Where land meets the ocean
Long shore Current
A current of water that runs parallel to the shoreline and moves sediments along the shoreline
Beaches
Deposits of sediment that are parallel to the shore
Barrier Islands
Sand deposits that are parallel to the shoreline, but are separated from the main land
Spit
Where a beach extends from land and exterminates in open water
Sandbar
Submerged or partly exposed ridge of sand or coarse sediment that is built by waves offshore from a beach
No-till Farming
Farmers leave plant stalks in the fields over winter months and plant "over" them in spring which protects the soil year round
Shelter Belts
Rows of trees planted along agricultural land to break the force of wind
Contour farming
Planting along natural contours of the land, which slows the flow of water down the land
Terracing
A farming method in which steep-sided, level-topped steps are built on the 2 sides of steep slopes
Planting Vegitation
What is the best way to prevent erosion