Earth Science Chapter 9 – Erosion and Deposition
Erosion – _____
Caused by (agents):
 _____
 _____
 _____
 _____
 _____
Sediment – _____
Deposition – _____
Gravity – force that moves rock and other materials downhill. Causes a mass movement
– any 1 of several processes that move sediment downhill
 Landslides – _____
 Mudflows – _____. Often occur in dry areas after a heavy rain.
 Slump – _____. The bottom falls out from under the soil.
 Creep – _____.
Water Erosion
Runoff – _____ (excess). Depends on 5 main factors
 Amount of rain received
 Vegetation (remember activity from last chapter to prevent erosion?)
 Type of soil
 Slope of the land
 How people use the land
 Increase runoff, increase erosion
 Causes
1. Rills and gullies – rills are _____ and gullies are _____. Water flows through it
and it moves sediment
2. streams and rivers – stream is _____, they flow together to make a river
3. tributaries – _____
Erosion by rivers causes
 _____
 _____
 _____ – wide flat area of land along a river
 _____ – large bend in a river
 _____ – meander that has been cut off from the rest of the river
Deposits by rivers make:
 Alluvial fans – _____
 Deltas – _____
 Add to a flood plain
Groundwater erosion
 Groundwater is _____
 Cause erosion through chemical weathering
 Water + carbon dioxide = _____
 Deposits cause stalactites and stalagmites (c=ceiling and g=ground)
 Limestone near groundwater at the surface can wear away and the overlying
ground can fall through = sinkhole
How water erodes
 Most sediment falls into a river as a result of mass movement and runoff. It can
erode from the bottom of sides of a river.
 Abrasion – _____ (think about sand in the waves at your feet at the beach).
 Amount of sediment that a river carries is a _____
 Ability of water to do this depends on
1. river slope – increase slope _____ flow and how much it carries
2. volume of flow – increase amount of moving water (such as a flood), increase
_____
3. shape of streambed – contact with sides and bottom of river _____ river flow. The
rougher the sides the more turbulence there is (water flowing in many directions)
4. water moves slowly at the sides and sediment is deposited. If a river curves water
moves fastest around the outside (erosion) and slowly around the inside (deposition).
Glacier – large mass of ice that moves slowly over land
 Continental glacier – _____. When they cover very large parts of the Earth it is
an ice age. Last one was 10,000 years ago.
 Valley glacier – _____.
 Form only in areas where more snow falls than melts. Once depth of snow and
ice reach more than 30-40 m brevity begins to pull glacier downhill.
Shaping the land
 Plucking – _____.
 Abrasion creates u-shaped valleys as rocks abraid the land underneath it.
 Till – _____
 Moraine – _____
 Kettle – _____
 Lakes
 Drumlin – _____
 Cirque – _____
 Arête – _____
 Horn – _____
 Fiord – _____
Erosion by waves
 Impact of wave can break apart rocks over time, making small cracks larger
 Abrasion by sand carried by wave can erode the rocks
 Headland – _____
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Sea stack
Cliff
Sea cave
Sea arch
Beach
Spit
Sandbar
Wind – causes erosion by _____ and _____ (weakest agent)
 Sand dune – _____ (crescent or star shaped depending no how the wind blows)
 Deflation –_____
 Loess – _____