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 Cool climate. This makes the frost and freeze cycle. Slopes. Things like to fall downhill. Exfoliation. Pressure is released from stuff underneath. 4. Biological. Things growing in cracks.

Things that contribute to chemical weathering. Warm wet climate. Things grow, and die, releasing CO2 Acid rain. Things dissolve in the acid. Type of rock. Some rocks dissolve faster than others. Warmth. Reactions go faster with heat. 5. Wet. Reactions usually need water.

Acid Rain ~ a summary Power plants give off sulfur dioxide. Lots of it. SO2. It combines with H2O to make H2SO4. The strongest acid Cars and homes give off CO2. It combines with H2O to make H2CO3. Carbonic acid Fossile fuels also give off nitric oxide. NO2. 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