Homework for Geology

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KEY to Homework Questions for Sedimentary and Metamorphic Rocks Lecture 6-7

Use these questions to test your knowledge of Sedimentary and Metamorphic Rocks

A. Short answer:

1. A rounded pebble would be a type of particle found in a conglomerate.

2. Salt and other minerals that form when a body of water dries up are called evaporites.

3. Sands are the size of detrital sediments larger than mudstones and smaller than conglomerates and breccias.

4. Coals are chemical sediments formed from trees that lived in coastal swamps.

5. Dynamothermal metamorphism develops from increased heat and pressure in an area of plate convergence.

6. Contact metamorphism takes place where rocks are heated by close contact with magma.

7. Foliation in gneisses is marked by the formation of distinct, single mineral bands of alternating felsic and mafic minerals.

8. Minerals stable in a narrow range of temperatures and pressures are called index minerals.

9. Quartzite is formed by metamorphism of relatively pure quartz sandstone, a type of sedimentary rock.

10. Contact metamorphism takes place where rocks are heated by close contact with magma.

B. Match the terms

1. Evaporite minerals f a. partially melted

2. Cementation g b. stable in narrow range T,P

3. Rounded particles > 2 mm e c. mud

5. Still water detrital sediment c d. dynamothermal metamorphism

4. New England d e. conglomerate

5. Banded metamorphic rock h f. gypsum and salt

6. Index mineral b g. glue grains together

7. Migmatite a h. gneiss

C. True or False?

1. Mudcracks are useful for "right-side-up" determinations. True or False?

2. The most abundant types of sedimentary rock are conglomerates. True or False? Mudstones = Mudrocks are most abundant

3. The degree to which sediment particles become rounded depends on their hardness, how far they are transported, and the energy of their collisions with other particles. True or False?

4. Deep lagoons are more effective in rounding sediment particles than swiftly flowing rivers. True or False? The water in deep lagoons is very slow

5. Detrital sedimentary rocks are classified on the basis of their particle sizes. True or False?

6. Conglomerates form in high energy (fast water) environments, such as under breaking waves at the beach. True or False?

7. Mudstones form in very low energy (slow water) environments, such as in very deep water. True or False?

8. In metamorphism, heat melts the minerals. True or False?

9. Foliation refers to a consistent orientation of the mineral grains perpendicular to the direction of greatest pressure. True or False?

10. Water facilitates metamorphic reactions by allowing movement of atoms and ions. True or False?

11. The ultimate composition of a metamorphic rock is determined by the parent rock. True or False?

12. The metamorphism that results entirely from the heat of hot circulating fluids is called contact metamorphism. True or False? That's hydrothermal

D. Multiple choice:

1) The main difference between a breccia and a conglomerate is: a) particle size.
b) particle shape.
c) color.
d) mineral composition.

2) Ripple marks in sediments that were transported by water (in cross-section they appear as "cross-beds"), can tell us: a) the direction of flow.
b) the current velocity
c) whether tides were important there.
d) All of the above

3) Of the following, the most likely environment of deposition for mudstone is: a) in the...
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