Download weathering and erosion slides

Weathering and
Erosion
Monroe 2008
Mechanical Weathering
a.
Ice
b.
Plants
c.
Animals
d.
Gravity
e.
Water
f.
Wind
Ice wedging on the
faces of the
Rushmore
Monument causes
cracks that must be
constantly repaired.
Exfoliation of a large chunk of granitic rock
Exfoliation of Red Rock in Nevada
Abrasion is the breaking away, and wearing away of one rock
by another.
This rock does not have
long to stand.
Chemical Weathering
Hydrolysis ~ the change in rocks due to the chemical
action of water
Carbonation ~ changes due to weak carbonic acid in
water. H2O + CO2 --> H2CO3
Oxidation ~ changes when elements in the rocks
combine with oxygen. 4Fe + 3O2 --> 2Fe2O3
Acid Rain ~ changes when pollution mixes with
water in rain, and forms acid, that eats away at rocks.
Hydrolysis
leaches
minerals out
of the soils
above, and
deposits them
in this cave as
stalagtites.
How ice wedging works.
Trees break apart rocks and
soils.
Mars is red
because of
oxidation of its
Iron.
Things that contribute to mechanical weathering
1. Cool climate. This makes the frost and freeze cycle.
2. Slopes. Things like to fall downhill.
3. Exfoliation. Pressure is released from stuff underneath.
4. Biological. Things growing in cracks.
Things that contribute to chemical weathering.
1. Warm wet climate. Things grow, and die, releasing CO2
2. Acid rain. Things dissolve in the acid.
3. Type of rock. Some rocks dissolve faster than others.
4. Warmth. Reactions go faster with heat.
5. Wet. Reactions usually need water.
Acid Rain ~ a summary
1. Power plants give off sulfur dioxide. Lots of it. SO2.
2. It combines with H2O to make H2SO4. The strongest acid
2. Cars and homes give off CO2.
3. It combines with H2O to make H2CO3. Carbonic acid
4. Fossile fuels also give off nitric oxide. NO2.
5. It combines with H2O to make nitric acid. HNO3.
Section 12.1 Review
1. In what kind of climate does ice wedging usually occur?
2. How do plants and animals weather rocks?
3. What agents (things) promote abrasion?
4. What chemical weathering process occurs when
minerals in the rock react with carbon dioxide?
5. Automobile exhaust contains nitrogen oxides. How
might these pollutants affect chemical weathering processes?
Section 12.1 Review
1. In what kind of climate does ice wedging usually occur?
High Elevations, Wide Temperature Swings, With
moisture.
2. How do plants and animals weather rocks?
3. What agents (things) promote abrasion?
4. What chemical weathering process occurs when
minerals in the rock react with carbon dioxide?
5. Automobile exhaust contains nitrogen oxides. How
might these pollutants affect chemical weathering processes?
Section 12.1 Review
1. In what kind of climate does ice wedging usually occur?
2. How do plants and animals weather rocks?
Roots get into cracks and expand them, animals burrow in
soils. Long time period.
3. What agents (things) promote abrasion?
4. What chemical weathering process occurs when
minerals in the rock react with carbon dioxide?
5. Automobile exhaust contains nitrogen oxides. How
might these pollutants affect chemical weathering processes?
Section 12.1 Review
1. In what kind of climate does ice wedging usually occur?
2. How do plants and animals weather rocks?
3. What agents (things) promote abrasion?
Rock collisions, running waters, gravity and wind
4. What chemical weathering process occurs when
minerals in the rock react with carbon dioxide?
5. Automobile exhaust contains nitrogen oxides. How
might these pollutants affect chemical weathering processes?
Section 12.1 Review
1. In what kind of climate does ice wedging usually occur?
2. How do plants and animals weather rocks?
3. What agents (things) promote abrasion?
4. What chemical weathering process occurs when
minerals in the rock react with carbon dioxide?
Carbonation
5. Automobile exhaust contains nitrogen oxides. How
might these pollutants affect chemical weathering processes?
Section 12.1 Review
1. In what kind of climate does ice wedging usually occur?
2. How do plants and animals weather rocks?
3. What agents (things) promote abrasion?
4. What chemical weathering process occurs when
minerals in the rock react with carbon dioxide?
5. Automobile exhaust contains nitrogen oxides. How
might these pollutants affect chemical weathering processes?
They cause acid rain, that dissolves rocks, statues and buildings.
Section 12.2 Review
1. Which mineral in igneous and metamorphic rocks
is least affected by chemical weathering?
2. Why does fractured rock weather more rapidly
than smooth rock?
3. What climatic factors influence weathering rates?
4. How does the topography of a region affect
weathering rates?
5. How would Cleopatra’s Needle probably have
been affected if it had been in the cold, dry climate of Siberia
for 100 years?
Section 12.2 Review
1. Which mineral in igneous and metamorphic rocks
is least affected by chemical weathering?
2. Why does fractured rock weather more rapidly
than smooth rock?
3. What climatic factors influence weathering rates?
4. How does the topography of a region affect
weathering rates?
5. How would Cleopatra’s Needle probably have
been affected if it had been in the cold, dry climate of Siberia
for 100 years?
VERY LITTLE
Section 12.2 Review
1. Which mineral in igneous and metamorphic rocks
is least affected by chemical weathering?
2. Why does fractured rock weather more rapidly
than smooth rock?
3. What climatic factors influence weathering rates?
4. How does the topography of a region affect
weathering rates?
Steep slopes are more affected by gravity, running
water, may have less soil above, especially if the steep slope
is on the side of a mountain.
Section 12.2 Review
1. Which mineral in igneous and metamorphic rocks
is least affected by chemical weathering?
2. Why does fractured rock weather more rapidly
than smooth rock?
3. What climatic factors influence weathering rates?
Amount of heat, and amount of water in environment.
Section 12.2 Review
1. Which mineral in igneous and metamorphic rocks
is least affected by chemical weathering?
2. Why does fractured rock weather more rapidly
than smooth rock?
There is more surface area for the chemicals like acid
rain to work on.
Section 12.2 Review
1. Which mineral in igneous and metamorphic rocks
is least affected by chemical weathering?
Quartz