20 terms

ESCI 111 Quiz 6

Clay minerals formed from gabbro or diorite bedrock illustrate which kind of weathering?
Which of the following is/are most susceptible to chemical weathering by dissolution?
What portion of an angular, fracture-bounded granitic block shows the highest rate of weathering?
the edges and corners
Why is the humus layer typically thicker in a cool, temperate forest soil than in a tropical rainforest soil?
Less humus is produced in the cool, temperate forest but the rate of decay and oxidation is slower than in a tropical rainforest.
What two factors speed up rates of chemical reaction and weathering in rocks and soils?
warm temperatures; very moist
In which area are pedocal soils most likely to be found?
a tropical rainforest in the Amazon Basin of Brazil
The finely divided, red, brown, and yellow soil-coloring minerals originate by what process?
precipitation of iron oxides during the chemical weathering process
Which of the following best describes the "Dust Bowl"?
areas of severe wind erosion on the Great Plains, 1930s
Which one of the following is an important, mechanical weathering process for enlarging fractures and extending them deeper into large boulders and bedrock?
frost wedging
Which of the following best describes sets of fractures in relatively fresh bedrock, such as granite, that are roughly parallel to the land surface?
sheeting fractures
Which term best describes those processes that move weathered rock materials and soils downslope?
mass wasting
Under similar warm, moist climatic conditions, why would basalt and gabbro generally have higher chemical weathering rates than rhyolite and granite?
The ferromagnesian minerals in the gabbro and basalt are subject to oxidation and chemical breakdown.
Which term describes a soil formed by weathering of the underlying bedrock?
Which one of the following statements best describes erosion?
the process by which weathered rock and mineral particles are removed from one area and transported elsewhere
Which of the following best describe the A soil horizon?
leaching zone
What mineral particles are the dominant coloring agents in reddish, brownish, and yellowish soils?
dust-sized grains of iron oxides
Which term best describes an accumulation of angular rock fragments at the base of a steep, bedrock slope or cliff?
talus slope
Lateritic soils form under what climatic conditions?
warm and moist as in a wet, tropical forest
From the land surface downward to the unweathered bedrock, which of the following is the correct order of the different soil horizons?
0, A, E, B, C, bedrock
In which area would weathering by frost wedging probably be most effective?
in moist, temperate climates