Geology Ch 6 – Flashcards
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Which term best describes all the processes that move weathered rock materials and soils downslope?
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Mass Wasting
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What process created finely divided red, brown, and yellow minerals in soils?
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Precipitation of iron oxides during the chemical weathering process
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Why is the humus layer typically thicker in a cool, temperate forest soil then in a tropical rainforest soil?
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Less humus is produced in the cool, temperate forest but the rate of decay and oxidation is slower than in a tropical rainforest
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Which of the following best describes sets of fractures in relatively fresh bedrock, such as granite, that are roughly parallel to the land surface?
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Sheeting fractures
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From the land surface downward to the unweathered bedrock, which of the following is the correct order of the different soil horizons
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O, A, E, B, C, bedrock
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Which one of the following statements concerning soil erosion is NOT true?
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Sheet erosion, rills, and arroyos or gullies develop mainly during prolonged droughts
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Which term describes a soil formed by weathering of the underlying bedrock?
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Residual
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Which regolith material results from frost wedging?
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Talus slopes
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Which of the following best describes the process of mineral subtraction of eluviation?
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Mineral subtraction of eluviation is the removal of very fine-sized silt and play particles from the A and E soil horizons
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Which of the following statements concerning humus is NOT true?
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Humus is readily leached from the B horizon in weakly acidic soil solutions
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During the 1930s, the United States suffered its greatest natural catastrophe. What great natural disaster affected both the farmers and the urbanites and led to the creation of the Soil Conservation Service?
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The Dust Bowl
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What portion of an angular, fracture-bounded granitic block shows the highest rate of weathering?
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The corners
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Which one of the following statements concerning mechanical weathering is NOT true?
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Mechanical weathering involves a major change in the mineral composition of the weathered material
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Which one of the following is an important mechanical weathering process for enlarging fractures and extending them deeper into large boulders and bedrock in temperate and arctic environments?
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Frost Wedging
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What two factors speed up rates of chemical reaction and weathering in rocks and soils?
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Warm temperatures; abundant moisture
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Which of the following materials are most susceptible to chemical weathering my dissolution?
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Calcite
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Assume that water filling a crack in a rock undergoes cycles of freezing and melting. Which one of the statements is true?
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Water expands as it freezes, causing the crack wall to be pushed apart
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Which one of the following statements best describes erosion?
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Erosion is the process by which weathered rock and mineral particles are removed from one are and transported elsewhere
