Transcript Ch. 11: Weathering and Erosion

Ch. 11: Weathering and Erosion
Vocabulary:
landform, weathering, erosion,
glacier, deposition, sediment, delta
Weathering
• Most landforms are made of rock.
• Rock is very hard, but can be
broken down by wind and water.
• This process is called weathering.
• Sand blows across rocks and eats
away at its surface.
• Rainwater gets into cracks in
rocks, then freezes; expanding
and cracking the rocks into pieces.
• Rocks located in rivers or
underwater are smoothed by
currents that flow through the
water running over them.
• Weathering is a process that takes
thousands of years.
Erosion and Deposition
• When weathering breaks
rocks into pieces, some of
those pieces stay where they
are, but some of them get
moved by the wind or water.
• Erosion is when rocks and
dirt gets picked up and
moved.
• Deposition is when rocks
and dirt get dropped backed
down.
Erosion and Deposition
• Erosion and deposition are
caused my many sources.
• Rivers pick up rocks and
dirt as they flow by.
• Glaciers pick up large rocks,
then melt leaving them
standing in fields.
• Sandstorms pick up large
amounts of sand and move it
from one area to another,
reshaping whole deserts.
• The dirt and rocks that get
left behind are called
sediment.
Reshaping the Earth’s Surface
Look at how much closer to
the rocks Niagra falls was
100 years ago.
Reshaping the Earth’s Surface
• Another major way the
Earth is reshaped is around
river deltas.
• A delta is an area at the end
of a river where dirt and
mud are deposited forming
forks in the waterway before
you reach the ocean.
• A delta is usually shaped
like a triangular fan.
The Amazon River Delta
Questions About Chapter 11
1. When a glacier melts and leaves a pile rocks,
this process is called?
2. Define the word weathering.
3. Which part of the natural earth-moving
process involves the actual picking up and
moving of weathered rock?
4. Which landforms develop near the mouth of
a river?
5. What are the two main causes of weathering?