Chapter 12 Test Review

1. Chapter 12 Test Review

2. What does the test comprise? • 20 multiple choice • 1 Diagram to label and answer questions • 2 essay questions

3. Exfoliation of granite occurs because of upward expansion. Basalt is a common rock on surface lava flows. Frost wedging, hydrolysis, and oxidation are weathering processes associated with this rock. Sharp-edged boulders on bare mountaintops are likely to be the result of frost wedging. A river carrying silt to the ocean is an example of erosion.

4. Mississippi flowing into the Gulf

5. Exfoliation

6. Basalt

7. The cracking of concrete sidewalks is an example of mechanical weathering. Water expands as it freezes, making ice wedging possible. Calcite is a mineral that dissolves most rapidly in carbonic acid. Hematite forms as a result of oxidation. Quartz pebbles with silica cement is a type of conglomerate most resistant to all weathering processes.

10. Hematite

12. Gravity is responsible for all mass movements. Ice, water, and wind are considered agents of erosion. About 25% of the Earth’s surface can be used to grow crops. Tropical forest soils are found in regions that are hot and rainy year-round. Talus is found at the base of a rocky cliff. Residual soil has underlying bedrock as its parent material.

14. Residual Soil

15. When large amounts of carbon dioxide, sulfur dioxide, or nitrogen compounds are released into the atmosphere, acid rain may form. Planting trees along edges of fields can reduce soil erosion. Mudflows occur when water carrying clay and silt moves rapidly downhill. Soil depletion occurs when planting and harvesting corn year after year removes nutrients from the soil in a field.

19. Soil Horizon A contains more humus than other layers.Soil Horizon B contains more clay and soluble minerals.

20. Essays Describe two techniques farmers can use to prevent soil erosion. Explain how these techniques are effective. Planting crops in rows parallel to land contours inhibits water flow from going downhill and carrying soil with it. Planting windbreaks on the windward sides of fields prevents wind erosion.

21. Flattening slopes into terraces inhibits erosion of soil by running water. No-till leaves crop areas less vulnerable to erosion because the soil is left relatively undisturbed. Planting different crops – one crop that leaves soil bare between rows, and one crop that covers the ground – in alternating strips inhibits erosion.

22. In what way is the mechanical weathering process of wetting and drying like the chemical weathering process of hydrolysis? How are the two processes different? Both processes are alike in that they both involve water. In wetting and drying, rock materials expand and shrink as they change from wet to dry. In hydrolysis, water is involved in chemical reactions that change minerals in a rock into new minerals.

23. The two processes are different in that wetting and drying breaks a rock into smaller pieces. The chemical composition of the small pieces is the same as the original rock. In contrast, hydrolysis changes the chemical composition of the original rock. These two processes are also alike because they both affect clay minerals