Download Weathering and Erosion

Erosion
Erosion
• The process by which natural forces move
weathered rock and soil from one place to
another.
EROSION AND SEDIMENT

The material moved by erosion is sediment.
Sediment may consist of pieces of rock or soil
or the remains of plants and animals.

Both weathering and erosion produce
sediment.
Deposition
• Deposition occurs where the agents of
erosion, deposit or lay down sediment.
Deposition changes the shape of the land.
Shaping Earth’s Surface

Weathering, erosion and deposition act
together in a cycle that wears down and
build’s up Earth’s surface.

Erosion and deposition are at work
everywhere on Earth. As a mountain wears
down in one place, new landforms build up
in other places.

The cycle of erosion and deposition is neverending.
TYPES OF EROSION

The erosion process occurs when water, ice, wind or
gravity moves fragments of rock and soil.

The types of erosion are:
Water Erosion
 Ice Erosion
 Wind Erosion
 Mass Movement

Water Erosion
• Runoff, rivers, streams
Runoff

Moving water is the major agent of the
erosion that has shaped Earth’s land surface.

Erosion by water begins with the splash of
rain. Some rainfall sinks into the ground.
Some evaporates or is taken up by plants.

As water moves over the land, it carries
particles of sediment with it. This moving
water is called runoff.
EROSION BY RIVERS
As
the river flows from the
mountains to the sea, the
river forms a variety of
features.
Through erosion, a river
creates valleys, waterfalls,
flood plains, meanders, and
oxbow lakes.

 As
water moves it carries sediment with
it. Any time moving water slows down, it
deposits some of the sediment.
 Deposition
creates landforms such as
alluvial fans and deltas. It can also add
soil to the river’s flood plain.
Ice Erosion
• Glaciers




Geologist define a glacier as any large mass of ice that
moves slowly over land.
There are two kinds of glaciers- continental glaciers
and valley glaciers.
A continental glacier covers much of the continent or
large island.
A valley glacier is a long, narrow glacier that forms
when snow and ice build up high in a mountain valley.
How Glaciers Shape the Land

As a glacier flows over the land, it picks up rocks in a
process called plucking. Beneath a glacier, the weight
of the ice can break rocks apart. These rock fragments
freeze to the bottom of the glacier. When the glacier
moves it carries the rocks with it.

Glacial Deposition occurs when a glacier melts,
it deposits the sediment it eroded form the land,
creating various landforms.
Wind Erosion
HOW WIND CAUSES EROSION

Wind cause erosion by deflation and abrasion.

Deflation is the process by which wind picks up the
smallest particles of sediment.

Abrasion by wind-carried sand can polish rocks, but
causes little erosion.

Wind Erosion and Deposition may form sand dunes,
and loess deposits.


Gravity is the force that moves rock and other
materials downhill. Gravity causes mass
movement.
The different types of mass movement include
landslides, mudflows, slump and creep.
Types of Mass Movement


Landslides- The most destructive type of mass
movement which occurs when rock and soil slide
quickly down a steep slope.
Mudflows- A mudflow is the rapid downhill
movement of a mixture of water, rock and soil.
Mudflows occur after heavy rains in a normally dry
area and can contain as much as 60% of water.
 Slump-
Occurs when a mass of rock and
soil suddenly slips down a slope. Unlike a
landslide, the material in a slump moves
down in one large mass.
 Creep-
Is the very slow downhill
movement of rock and soil. Creep often
results from the freezing and thawing of
water.
Mass Movements
• Landslides, mudslides, slump and creep
landslide clip.mpeg