Assignments:

1. Porphyritic texture forms from

• A. initial rapid cooling then slow cooling of magma
• B. initial slow cooling then rapid cooling of magma
• C. extremely rapid cooling of magma
• D. escape of gas bubbles during cooling of lava

2. During crystallization of a basaltic magma _____________ is the first mineral to crystallize.

• A. olivine
• B. pyroxene
• C. plagioclase
• D. quartz

3. How does water influence the formation of magma?

• A. rocks with higher water content melt at higher temperatures
• B. rocks with higher water content melt at lower temperatures
• C. rocks with higher water content produce basaltic magma
• D. rocks with higher water content produce rhyolitic magma

4. According to theory, if fractional crystallization occurs (e.g. by early-formed crystals settling to the bottom of the magma chamber)

• A. the remaining magma becomes more mafic-rich
• B. the remaining magma does not change in composition
• C. the remaining magma becomes more rich in silica
• D. the magma cools faster

5. A very large igneous intrusion, such as the one that forms the core of the Sierra-Nevada mountain range, is called a

• A. sill
• B. dike
• C. stock
• D. batholith

6. Obsidian, or volcanic glass forms by

• a. lava cools so fast minerals can't crystallize
• b. lava cools so fast minerals are very fine-grained
• c. rock is shattered during an eruption
• d. volcanic mudflow deposition

7. Extrusive igneous rocks have smaller crystals than intrusive igneous rocks because _______.

• A. Intrusive igneous rocks cool slower than extrusive rocks
• B. Extrusive igneous rocks cool slower than intrusive rocks
• C. Intrusive igneous rocks melt slower than extrusive rocks
• D. Extrusive igneous rocks melt slower than intrusive rocks

8. Most common rock-forming minerals are ______.

• A. carbonates
• B. oxides
• C. silicates
• D. sulfides

9. What type of rocks form from the solidification of molten rock?

• A. igneous
• B. mineralogic
• C. sedimentary
• D. metamorphic

10. What types of rocks form from pre-existing rocks that are subjected to high temperature and pressure?

• A. igneous
• B. mineralogic
• C. sedimentary
• D. metamorphic

11. A basalt is an example of a(n) _______ rock.

• A. igneous
• B. mineralogic
• C. sedimentary
• D. metamorphic

12. Which best describes basalt?

• A. a foliated metamorphic rock
• B. a non-foliated metamorphic rock
• C. a coarse-grained light colored igneous rock
• D. a fine-grained dark colored igneous rock

13. Clastic sediments form from _______.

• A. rapid cooling of molten sediments
• B. physically deposited particles of sediment
• C. precipitation of sediments from sea water
• D. accumulation of calcium carbonate shells

14. Limestone, a rock that forms from the shelly remains of organisms, is an example of a(n) _______.

• A. extrusive igneous rock
• B. intrusive igneous rock
• C. clastic sedimentary rock
• D. chemical sedimentary rock

15. An igneous rock that is coarse-grained and contains abundant quartz is _______.

• A. granite
• B. rhyolite
• C. basalt
• D. gabbro

16. Which of the following properties is diagnostic of a sedimentary rock?

• A. layering
• B. foliation
• C. glassy texture
• D. orogeny

17.Sediment forms as a result of rock weathering.

• A) TRUE
• B) FALSE

18.Clastic sedimentary rocks do not contain particles that have been altered as a result of chemical weathering.

• A) TRUE
• B) FALSE

 

19.Weathering is an important part of the process whereby sediment becomes sedimentary rock.

• A) TRUE
• B) FALSE

20.Sedimentary rocks never contain valuable natural resources because they are highly weathered.

• A) TRUE
• B) FALSE

21.Sediments only form as a result of the weathering of igneous rocks.

• A) TRUE
• B) FALSE

22.Quartz is a common component of sedimentary rocks because it is resistant to chemical weathering.

• A) TRUE
• B) FALSE

23.There is no upper limit to the size a sediment particle can have.

• A) TRUE
• B) FALSE

24.Chemical sedimentary rocks are less common than Detrital sedimentary rocks.

• A) TRUE
• B) FALSE

25.Chemical sedimentary rocks are always formed as a result of chemical weathering of other rocks.

• A) TRUE
• B) FALSE

26.Chemical sedimentary rocks typically form as precipitates from solutions.

• A) TRUE
• B) FALSE

27.Sedimentary rocks reveal a great deal about Earth surface conditions as they were forming.

• A) TRUE
• B) FALSE

28.Ripple marks preserved in a sandstone may be used to determine the direction a current was flowing.

• A) TRUE
• B) FALSE

29.Sediment can be transported great distances from its source area before being deposited.

• A) TRUE
• B) FALSE

30.Cement that forms to bind sediments is usually precipitated from solution.

• A) TRUE
• B) FALSE

31.Boulders cannot be transported or deposited to form sedimentary rocks.

• A) TRUE
• B) FALSE

32.The grain size of clastic sedimentary rocks may provide clues to the environment in which the sediments were deposited.

• A) TRUE
• B) FALSE

33.Geologists use sedimentary rocks to reconstruct the geologic history of Earth.

• A) TRUE
• B) FALSE

34.Some successions of sedimentary rocks allow geologists to interpret the history of sea-level oscillations on Earth.

• A) TRUE
• B) FALSE

35.Coral reefs are a type of chemical sedimentary rock.

• A) TRUE
• B) FALSE

36.Earth is the only planet with sedimentary rocks.

• A) TRUE
• B) FALSE