Monday 11-10-14
• Fill out plans for week
• Update SN
• Turn in Erosion/Weathering Video WS
• Weathering & Erosion Notes
• p. 383 Textbook
preAP
• Return Data and Results
• Entire Research paper due Wednesday
– Fix anything from data and results sheet
– Add a title page
Retest Procedures
If you want to retest to bring your grade up to a maximum
of 85%:
1. Corrections to Original Test Any day during tutorials
(Explain right answer for all missed questions.)
2. Reteach Tuesday morning or afternoon.
– Must arrive within 5 minutes of tutorial start time.
– Reteach lesson by teacher
– Worksheet to complete at home & get signed by parents (so
they know your original grade)
3. Retest Thursday morning or afternoon
-Bring completed/signed worksheet as ticket to retake test
-Arrive within 5 minutes of tutorial start time.
Objectives
• Explain how weathering, erosion, and
deposition change the surface of the Earth
• Differentiate between chemical and
mechanical weathering
Weathering and Erosion
Weathering
Weathering is breaking down and
wearing away of rock material.
Climates affects the rate of weathering:
1. Hot damp
conditions tend
to rot material
quicker
Inca city of Machu Picchu in
the Andes Mountains of Peru
Mayan City of El Mirador in the
rainforest of Belize.
2. Cooler dry
conditions take a
longer time to
rot.
Types of Weathering
1. Physical
2. Chemical
Physical or Mechanical Weathering
The breaking up of rock material into
smaller pieces is physical or mechanical
weathering.
There is NOT a change in the chemistry
(composition) of the rock.
Types of Physical or Mechanical Weathering
a. Abrasion - works like sand paper and
wears the rock down by ‘rubbing’
water, ice, sand or
wind across it.
Balancing rocks of
Zimbabwe, Africa
Dust Storm in New Mexico
b. Temperature – a significant difference
between hot and cold temperatures over
a period of time.
Rock spikes in
Wyoming
Exfoliation
domes at
Enchanted
Rock, Texas
c. Frost action – the continuous
freezing and melting of water
d. Gravity – pulls rock material down
Talus slopes in the Sierra
Madres.
Land slide in Peru
e. Organic activity – burrowing animals and
root pry.
Worm tubes from the Sea
of Cortez
Root pry – Camp
Goddard, Oklahoma
Chemical Weathering
The breaking down of the composition of a rock into a
new and different substance is chemical weathering.
Types of Chemical Weathering
a. Oxidation – the combining of elements (like iron)
reacting with oxygen; ‘rusting of rock’- rock turns red.
Eastern Tennessee
Rusted Hematite
Acids: Rock reacts with water, gases and solutions to
form acids which can add or remove elements from
minerals
Carlsbad Caverns,
New Mexico: carbonic
acid
Water seeping from a
historic gold mine,
Reefton, New Zealand
has elevated arsenic and
antimony.
The Parthenon in
Greece shows
discoloration and
chemical weathering
effects from air pollution
and acid rain.
Garden of the Gods, Colorado
The transfer of rock material to another
location is erosion.
The 5 agents of erosion
Running water
Wind
Groundwater
Glaciers
Ocean waves and currents (beach/shoreline)
Erosion is a force that happens as a result
of 2 factors of motion
1. Gravity – downward pull
2. Momentum – speed/velocity
Gravity and momentum interact to carve out
and build up the earth’s surface by…..
1. Erosion – carving out process
2. Deposition – building up process
I. Wind Erosion & Deposition
In arid (dry) landscapes the primary erosional force
is wind.
Wind picks up dry particles and hurls
them along, blasting them against
exposed rock - the process is called
sand blasting.
Landscape Bridge, Arches National Park, Utah
Shoulder partners:
1. What feature was caused by wind erosion?
2. Predict how this feature will continue to change with
erosion.
Holes in the rocks
1. Hole will get bigger
2. Gravity might pull it down.
Landscape Bridge, Arches National Park, Utah
The most common deposits
of wind are sand dunes.
Particles of sand are carried
along and deposited by the
wind.
They move over the ground
as small ripples and larger
dunes.
NASA Satellite view of White Sands.
Depositional feature: sand dunes.
White Sands National Monument, New Mexico
Shoulder partners discuss and name the
depositional features below.
Sand dunes & Sand bar formation
Shoulder partners
1. What is the difference between summer and winter erosion?
More erosion in the winter.
II. Groundwater erosion is carried out by 3 processes.
Water percolates through rock and
dissolves it. (weathering)
Dissolved rock is moved as it drips through
Dissolved rock is then deposited.
Natural Bridge Caverns, San Antonio, Texas
Shoulder partners discuss and
name the erosional and
depositional features below.
erosional feature – dissolved rocks dripping
depositional feature – dissolved limestone
is redeposited to form stalagmites and
stalactites
III. Glaciers, “rivers of ice”, creep down from
mountains as a result of the pull of gravity, and
have a tremendous influence on the earth’s
surface.
Weight of the glacier exerts and great deal of
pressure causing the ice to move like putty.
The great weight grinds out the floor and sides
and bulldozes the debris down the slope.
This process created the Great Lakes.
McGinnis Glacier, Alaska Range, Alaska
As a glacier slowly retreats, it leaves
behind the material it ‘bulldozed’ as it
moved down the mountain.
This material is called moraine
This process created New York’s
Manhattan Island.
Hubbard Glacier, Alaska
Shoulder partners discuss
and name the erosional and
depositional features
below.
erosional feature –
bulldozing the debris down
the slope and cutting a U
shaped basin. (depression on
Earth’s surface)
depositional feature –
moraine – debris left behind
Amazon River, Brazil, South America
Rivers are flowing
bodies of waters
There are rivers on
every continent
(except Antarctica).
Rivers are an important part of the
Earth's water cycle – they are runoff.
Runoff sculpts the surface of earth as it transports
large amount of water and dirt to the ocean
Rivers generally start
at a high elevation
and flow downward to
sea level. They may
begin as snow melt or
a natural spring.
The early course of a river
(the youngest part) is
marked by greater
momentum (speed) due to
the steeper slope and
gravity.
Creates a “V” Shape. The
faster the river, the
steeper the “v”shape.
Source of the
Mississippi River
at Lake Itasca,
Minnesota
Snake River Canyon, Oregon
As the river ages it
stretches across flatter
land. With the
decreased slope the
river’s path develops
bends and curves called
meanders
Mississippi River as it flows through the Great Plains
Oxbow lakes are meanders
that are cut off from the
main channel.
_____________cuts
Erosion
on the
outside of the meander until
the meander is cut off.
_____________eventually
Deposition
seals off the meander
leaving a ‘lake’ behind.
The lake will eventually
dry up – becoming a
swamp and then dry land.
The mouth of a river is
where it flows into a large
body of water..
At the mouth of the
river, mud is
deposited forming
_________
a new land mass
called the delta.
Alluvial Fan
of Delta
Mississippi River Delta. Louisiana