Name: _________________________________________ Date: _______________ Period: _______
Erosion and Deposition
Waves
The energy in waves comes from wind that blows across the water’s surface. Waves are the major force of
erosion along the coasts. Waves can erode land by impact and abrasion. Eventually, waves may erode so much
of the base of a cliff that the rock above collapses. The result is a wave-cut cliff. Another feature created by
wave erosion is a sea arch. A sea arch forms when waves erode a softer rock that underlies a layer of harder
rock. Waves not only erode the land, they also deposit sediment. As waves reach the shore, they drop the
sediment they carry, forming a beach. A beach is an area of wave-washed sediment along a coast. The
sediment deposited on beaches is usually sand. Some beaches however are made of small fragments of coral or
sea shells piled up by wave action. Waves usually hit shores diagonally because a shoreline’s shape varies.
1. Circle the two of the processes by which waves can cause erosion.
2. Underline how is sediment deposited along the coast.
3. The sediment that travels onto the beach with the wave is
______________.
4. Waves often push water up onto a beach an angle, but gravity pulls
it back perpendicular to the shore. Draw an arrow that shows this
perpendicular movement of water.
5. Relationship: The _______________ the wave size and the
_____________ the erosion?
Wind
Wind is the weakest agent of erosion but is still very powerful at shaping the land in areas where there are few
plants to hold the soil in place. The main way that wind causes erosion is by deflation. Deflation is the process
by which wind removes surface materials. The stronger the wind, the larger the particles it picks up. Abrasion
by wind carried sand can polish rock but causes little erosion. All of the sediment picked up by wind eventually
falls to the ground. Wind erosion and deposition may cause sand dunes and loess deposits. When the wind
strikes an object, the result is usually a sand dune. Sand dunes are typically made up of coarser sediments
carried by wind. The finer sediments are sometimes deposited in layers far from their source. This is called
loess. Large loess deposits help form fertile soil.
1. Circle the two processes by which wind causes erosion.
2. Underline how sand dunes and loess deposits form.
As wind speed increases over soil with no vegetation, small
sand particles (0.1–0.5 mm in diameter) begin to move. At
first, particles on the surface creep forward. As wind speed
continues to increase, small particles fly through the air for a
few centimeters before falling back to the surface. This is
called saltation. When the saltating particles hit the ground,
they may dislodge other particles, especially smaller
particles. Finally, if the wind speed is high enough, small
particles become suspended in the air. Suspended particles
are carried high into the air where they become the dust of a
dust storm.
2
1
3
3. Which of the three ways shown in Figure A would likely carry the sediment and create a loess?
Glaciers
Glaciers can form only in an area where more snow falls and then melts. The movement of a glacier changes
the land beneath it. They move slowly but are a major force of erosion. Plucking and abrasion are the two
processes by which glaciers erode the land. Plucking is when a glacier flows over the land and picks up rocks.
The rock fragments can freeze to the bottom and is carried along with the glacier, it was “plucked” from the
ground. Abrasion is when rocks remain on the bottom of a glacier and are dragged across the land. Along the
way it scratches the bedrock below. As it travels glaciers collect a large amount of rock and soil. When a
glacier melts it will deposit this sediment creating different landforms. A till is the mixture of sediments that a
glacier deposits on the surface. The till on the edges of a glacier form a ridge called a moraine.
1. Circle the two processes by glaciers can cause erosion.
2. Use the labeled diagram to choose three features formed by glacial deposition and describe them.
1. ______________________________________________________________________________
______________________________________________________________________________
2. . ______________________________________________________________________________
______________________________________________________________________________
3. . ______________________________________________________________________________
______________________________________________________________________________
Water Erosion
Moving water is the major agent of the erosion that has shaped Earth’s land surface. However, water in all its
forms can cause erosion. Raindrops (especially in dry environments) create splash erosion that moves tiny
particles of soil. In streams, water is a very powerful erosional agent. The faster water moves in streams the
larger objects it can pick up and transport. Fine sand can be moved by streams flowing as slowly as threequarters of a mile per hour. Streams erode their banks in three different ways: 1) the hydraulic action of the
water itself moves the sediments, 2) water acts to corrode sediments by removing ions and dissolving them and
3) particles in the water strike bedrock and erode it. Through erosion, a river creates valleys, waterfalls, flood
plains, meanders, and oxbow lakes. As water moves, it carries sediments with it. Any time moving water slows
down it drops or deposits some of its sediment. Deposition creates landforms such as alluvial fans and deltas.
It can also add soil to a river’s flood plain.
Groundwater is when some rain and snow soaks into the ground. Groundwater can cause erosion through a
process of chemical weathering. When water sinks into the ground it combines with carbon dioxide to form a
weak acid called carbonic acid. This can break down limestone hallowing out pockets in the rock. Over time
these pockets become very large forming caves and caverns. Deposits called stalactites and stalagmites often
form.
1. Circle the major cause of erosion on Earth’s surface.
2. Underline the results of deposition along the course of a
stream or river.
3. Underline how can groundwater contribute to erosion.
4. Using figures to the right answer the following questions.
a) What does the Mississippi River do as it flows through
its delta?
_______________________________________
_______________________________________
_______________________________________
b) Label the river’s main channel on Figure 1.
Figure 1