Date post: | 15-Jul-2015 |
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True or False: The Earth’s surface has stayed the same for thousands of
years
The Earth’s surface is always changing!
Wind causes weathering
What evidence of weathering do you see
in this picture?
Why wasn’t this mass of land weathered
away?
ErosionThe process by which water, ice, wind or
gravity moves fragments of rock and soil.
What evidence of erosion do you see in
this picture?
Erosion is Movement of Sediment!
• This process, known as Erosion, is gradually
wearing down the surface of the earth.
• Erosion is the process by which weathered rock and soil (sediment) are moved from one place
to another. • Erosion carves the Earth's surface creating canyons, gorges, and
even beaches.
What do you think has caused this rock to look this way?
Wind Erosion
• As the wind blows it picks up small particles of
sand/sediment and blasts large rocks with the abrasive particles, cutting and shaping
the rock.• The intensity of wind erosion
is determined by:• Sum (amount)
• Speed• Slope
• Surface
Water causes Erosion
When rain falls to the Earth it can evaporate, sink into the ground, or flow over
the land as Runoff. When it flows over land,
erosion occurs.
Runoff picks up pieces of rock and "runs" downhill cutting tiny grooves (called rills) into the land.
Water causes Erosion
How much erosion takes place is
determined by the: • Sum (amount)
• Slope• Speed
• Surface
Can you act increasing and decreasing the
four S’s?
Ice Causes Erosion
Glaciers wear down the landscape; by picking up and
carrying debris that moves across the land along with
the ice.
Ice Causes ErosionGlaciers can pick up and carry sediment that ranges in size
from sand grains to boulders bigger than houses.
Moving like a conveyor belt and a bulldozer, a single glacier can move millions of tons of material!
Ice Causes Erosion
How much erosion takes place is determined by
the: • **Sum (Glaciers are
massive!)
• Slope• Speed
• Surface
Gravity causes erosion
landslide clip.mpeg
Creep, Slump, Landslides, Mudslides, and Avalanches.
These are examples of mass movement (or called mass wasting)
Slower Faster
Gravity causes Erosion
How much erosion takes place is determined by
the:
• Sum• **Slope• Speed
• **Surface
Deposition
Rock particles that are picked up and transported during erosion will ultimately be deposited
somewhere else
Deposition is the process by which sediments (small particles of rock) are laid down in new locations. • Together, Erosion and Deposition build new
landforms. • Deltas
• Canyons• Meanders
• Floodplains
Delta
Where rivers meet the ocean is called the mouth of the river.
Soil and dirt carried by these rivers is deposited at the
mouth, and new land is formed. The new,
soil-rich land is known as a Delta
Canyons
This simple animation provides you with a visualization of how the
Colorado River has "downcut" into the rock layers of the Grand
Canyon.
How long it took to carve the Grand Canyon is debated by
geologists. Some estimates are between 6
and 8million years, which is very recent
by comparison.
Canyons are large valleys created by a
river or stream.
Meanders
Meandering streams wander side to side as they constantly seek out the lowest elevation.
This constant motion creates a series of S-shaped “loops”.
Meanders
Stream Velocity varies from one side to the other side of the “S”, resulting in erosion in some places and
deposition of sediments in others.
Floodplains
• Floodplains form along the banks of mid-order streams and larger rivers.
• These are low-lying areas along the sides of a river channel that have regular times of heavy waterflow to cause the river to spill over and flood the land.