Geos. 101, Lecture 1 (MWF - Kresan)
Review Questions for Second Exam (Fall 1998)
Multiple Choice – Circle the BEST answer.
1. Which of the following is a sheet silicate mineral?
A. Clay mineral.
B. Feldspar.
C. Amphibole.
D. Gypsum.
E. Graphite.
2. The most abundant class of minerals is the
A. oxides.
B. silicates.
C. carbonates.
D. sulfates.
3. The most abundant mineral in the upper mantle is
A. feldspar.
B. calcite.
C. hematite.
D. olivine.
4. The continental crust consists mostly of
A. olivine.
B. basalt.
C. Fe + Ni.
D. granite.
5. Amphibole and pyroxene are
A. chain silicates.
B. sheet silicates.
C. framework silicates.
D. non-silicates.
6. A rock with the same mineralogy as granite but with fine grain size is
A. basalt.
B. obsidian.
C. gabbro.
D. rhyolite.
E. pumice.
7. A rock that contains no minerals is called
A. granite.
B. andesite.
C. basalt.
D. obsidian.
E. quartz.
8. The most common mineral in volcanic rocks is
A. feldspar.
B. quartz.
C. micas.
D. olivine.
E. pyroxene.
9. As a magma crystallizes and differentiates, following the Bowen reaction series, the lower temperature fractions of liquid magma are progressively
A. enriched in magnesium.
B. depleted in potassium.
C. depleted in silica.
D. enriched in silica.
10. Which of the following are the first minerals to form (i.e., at the highest temperatures) in Bowen's reaction series?
A. Quartz and feldspar.
B. Halite and gypsum.
C. Olivine and plagioclase.
D. Mica and chert.
E. Amphibole and plagioclase.
11. Most of the rock exposed on a shield volcano is
A. pyroclastic in origin.
B. ash and bombs.
C. felsic in composition.
D. basalt.
E. gabbro.
12. The most common gas released during eruptions is
A. water.
B. hydrogen.
C. carbon dioxide.
D. nitrogen.
E. sulfur.
13. Basalt can be produced by the partial melting of
A. rhyolite.
B. ultramafic rocks.
C. gabbro.
D. a mixture of gabbro and oceanic sediments.
14. Which of the following is likely to lower the melting temperature of a rock?
A. High pressure.
B. Only one mineral present in the rock.
C. Water under pressure.
D. Bowen's Reaction Series.
15. A rock containing no quartz and approximately equal amounts of plagioclase feldspar and ferromagnesian minerals would be
A. shale.
B. rhyolite.
C. ultramafic rock.
D. andesite.
16. Which characteristic best distinguishes intrusive from extrusive igneous rocks?
A. Composition.
B. Grain size.
C. Specific gravity.
D. Color.
E. Porphyritic versus non-porphyritic texture.
17. Which pair of rocks are associated with high silica content?
A. Basalt and gabbro.
B. Granite and andesite.
C. Ultramafic rocks and rhyolite.
D. Rhyolite and granite.
E. Diorite and andesite.
18. Andesites are predominantly the product of
A. partial melting of ocean crust and sediments.
B. partial melting of ultramafic rocks from the mantle.
C. partial melting of granite and granodiorite.
D. fractional crystallization of granite.
19. Rhyolite volcanoes build much steeper lava cones than basalt volcanoes because rhyolite lava
A. contains less gas than basalt lava.
B. is richer in silica than basalt lava.
C. cools more quickly than basalt lava.
D. is less dense than basalt lava.
20. Active volcanoes are concentrated
A. along zones of tension in the lithosphere.
B. along zones of compression in the lithosphere.
C. along both zones of tension and compression in the lithosphere.
D. where the Earth's crust is very thin.
21. Which of the following is a form of pluton?
A. Stock.
B. Batholith.
C. Dike.
D. Sill.
E. All of the above.
22. Composite volcanoes are commonly associated with
A. the San Andreas fault.
B. ocean spreading centers.
C. convergent plate boundaries.
D. the Atlantic Ocean basin.
23. Explosive volcanic eruptions are usually associated with
A. basaltic lavas.
B. magmas which are low in both silica and dissolved gases.
C. magmas rich in silica and dissolved gases.
D. shield volcanoes.
24. Calderas are usually associated with
A. basaltic lava forming as flows.
B. abundant ash and related pyroclastic debris.
C. relatively quiet eruptions.
D. shield volcanoes.
25. If someone informed you that an eruption had taken place at an undisclosed location and that the lava merely flowed out of a fissure and spread rapidly over a large area, you would inform that person that the rock type being formed would most probably be
A. granite.
B. quartzite.
C. andesite.
D. basalt.
E. rhyolite.
26. Fine-grained feldspar weathers more rapidly than coarse-grained feldspar because
A. relatively more surface area is available to be attacked by solution.
B. smaller grains are mechanically less stable, so they tend to fracture more easily.
C. chemical bonds are weaker in the smaller grains than large ones.
D. smaller grains pack less closely together, allowing water to percolate through the rock more easily.
27. The production of soil is described as a positive feedback process because
A. once a layer of soil is formed, the underlying rock is protected from further weathering.
B. rainwater becomes more acidic as it percolates through the soil, and weathering of underlying rock is promoted.
C. carbon dioxide in rainwater is used up by organisms so weathering of underlying rock is impeded.
D. soil consists of organic material as well as the breakdown products of rock weathering.
28. Which of the following minerals is most stable under Earth's surface weathering conditions?
A. Olivine.
B. Ca-feldspar.
C. Amphibole.
D. Quartz.
29. The rate of chemical weathering is fastest in a climate with
A. high temperature and low rainfall.
B. high temperature and high rainfall.
C. low temperature and low rainfall.
D. low rates of mechanical weathering.
30. The accumulation of calcium carbonate in a pedocal soil indicates that it formed in a
A. warm climate, with high precipitation.
B. warm climate, with low precipitation.
C. cool, forested region.
D. tropical climate.
31. The major source of salts dissolved in ocean water comes from
A. marine organisms.
B. weathering of the land surface and volcanic volatiles.
C. weathering of the ocean crust.
D. meteorites.
E. none of the above.
32. Acid rain __________ the potential for chemical weathering.
A. decreases.
B. has no affect on.
C. increases.
D. neutralizes.
33. The most important source of acid for chemical weathering is
A. Volcanic gases.
B. Plant decay.
C. Acidic water draining from mines.
D. Hot springs.
E. Carbon dioxide dissolved in water.
34. Which of the following is not a result of weathering of rocks?
A. Formation of clay minerals.
B. Solution of part of the rock with transport in solution in ground water or surface water.
C. Formation of feldspar minerals.
D. A decrease in the size of the rock and mineral particles.
E. Production of iron oxide minerals.
35. The type of soil that is widespread in the eastern United States is
A. pedalfer.
B. laterite.
C. alkali soil.
D. pedocal.
E. bauxite.
36. Pedocal soils are
A. typically enriched in aluminum in the C horizon compared to laterite soils.
B. typically enriched in calcium carbonate.
C. strongly leached soils and typically lack any significant amount of soluble material.
D. typically enriched in iron and aluminum in the B horizon compared to pedalfers.
37. Pedocal soils generally form in
A. warm climates, with high precipitation.
B. cool climates, in timbered areas.
C. warm climates, with low precipitation.
D. tropical climates, with extended periods of weathering.
38. Lateritic soils are typically produced in
A. warm climates, with high precipitation.
B. cool climates, in timbered areas.
C. warm climates, with low precipitation.
D. moderate climates, with moderate precipitation.
39. The most important factor in soil development is
A. topography.
B. climate.
C. parent rock.
D. time.
40. Soil fertility is controlled by
A. the clays and organic matter in the soil.
B. the degree of chemical weathering.
C. the climate.
D. all of the above.
41. The most fertile soils tend to occur in rock material which is
A. intensely weathered.
B. very weakly weathered.
C. moderately weathered.
D. not weathered at all.
42. You are an architect for a high-rise building in New York City. Which of the following naturally occurring materials would provide a facing to the building which is most resistant to weathering?
A. Granite.
B. Olivine basalt.
C. Limestone.
D. Halite.
43. Exfoliation refers to
A. trees losing their leaves due to soil deficiencies.
B. the parallel layering in metamorphic rock.
C. the tendency of some rocks to weather more rapidly than others.
D. the tendency of rocks such as granite to crack into slabs due to pressure release.
E. none of the preceding.
Short Answers – Briefly discuss the relationship between the following paired terms.
1. Andesite / Diorite
2. Granite / Rhyolite
3. Pyroxenes / Amphiboles
4. Volcanism / Ocean crust
5. Shield volcanoes / Basalts
6. Acid rain / Chemical weathering
7. Feldspars / Clay minerals
8. Lateritic soil / Tropical climate
9. Obsidian / Cooling
10. Soil fertility / Clay minerals
11. Physical weathering / Chemical weathering
12. Water / Physical weathering
Discussion Questions – See your lecture notes for review questions that I highlighted in lecture.