Exam 1: Geology 101, Fall 2004

Exam 2 (the rock test!): Geology 101, Fall 2004

name____________________________

Select the best answer and fill in the appropriate answer on the scan sheet provided. Make sure you have all SEVEN pages of the test and your ID # and name are correctly entered on the scan sheet!

1. _____ is the type of rock that comprises Moscow Mountain.

A. Basalt

B. Granite

C. Shale

D. Schist

E. none of the above

2. _____ is the type of rock that the City of Moscow lies on.

A. Basalt

B. Granite

C. Shale

D. Schist

E. none of the above

3. Which of the following sequences of events (from oldest to youngest) best describes the local geology?

A. formation of the Belt rocks, intrusion of granite, lava flows forming basalts

B. lava flows forming basalts, intrusion of granite, formation of the Belt rocks

C. lava flows forming basalts, formation of the Belt rocks, intrusion of granite

D. formation of the Belt rocks, lava flows forming basalts, intrusion of granite

E. none of the above

4. The fossils we saw at Clarkia were deposited in lake sediment. The lake was formed when a/an _____ dam blocked a stream.

A. ice

B. basalt

C. rock slide

D. earthen

E. none of the above

5. Although we didnπt see this area on our field trip, the Scablands in central Washington formed in a major flood approximately 10,000 years ago. The flood was caused when a lake formed behind a/an _____ dam in Montana emptied within a few hours.

A. ice

B. basalt

C. rock slide

D. earthen

E. none of the above

6. Palouse hills near Moscow formed over the past 10,000 years, mainly by:

A. water deposition of sediment

B. ice deposition of sediment

C. wind deposition of sediment

D. wind erosion of sediment

E. none of the above

7. The oldest rocks we saw on the field trip were approximately (a)_____ years old, while the youngest rocks were approximately (b)_____ years old.

A. (a) one million, (b) 100,000

B. (a) 200 million, (b) 5-15 million

C. (a) one billion, (b) 5-15 million

D. (a) one billion, (b) 65 million

E. (a) one billion, (b) 100 million

8. Approximately 800 million years ago a/an (a)_____ plate boundary existed in our area, while approximately 100 to 200 million years ago a/an(b)_____ plate boundary existed in our area.

A. (a) diverging, (b) transform

B. (a) transform, (b) diverging

C. (a) converging, (b) diverging

D. (a) diverging, (b) converging

E. none of the above combinations

9. The tree leaves we see preserved at Clarkia can be used to infer past climatic conditions. Based on those fossils, we know the climate in northern Idaho 15 millions years ago was:

A. warmer and drier

B. warmer and wetter

C. cooler and drier

D. cooler and wetter

E. none of the above

10. There are two main types of igneous rocks: (a)_____ igneous rocks, which formed at or near the earthπs surface, and (b)_____ igneous rocks, which formed deep in the earth.

A. (a) granite, (b) basalt

B. (a) granite, (b) rhyolite

C. (a) extrusive, (b) intrusive

D. (a) intrusive, (b) extrusive

E. none of the above combinations

11. Igneous rocks that form on the earthπs surface are composed of (a)_____ with the naked eye because the lava that formed them (b)_____

A. (a) minerals that are large enough to see, (b) cooled very rapidly

B. (a) minerals that are too small to see, (b) cooled very rapidly

C. (a) minerals that are too small to see, (b) cooled very slowly

D. (a) minerals that are large enough to see, (b) cooled very slowly

E. none of the above combinations

12. Because the appearance of rocks often gives clues to where they formed, geologists often use the words extrusive and _____ as synonyms.

A. aphanitic

B. phaneritic

C. plutonic

D. clastic

E. none of the above

13. We talked about three different magma compositions. (a)_____ was the highest in Fe, while (b)_____ was the lowest in Fe.

A. (a) Felsic, (b) intermediate

B. (a) Felsic, (b) mafic

C. (a) Mafic, (b) felsic

D. (a) Mafic, (b) intermediate

E. none of the above combinations

14. There are several different types of volcanoes, and some of them are composed of different rock types. For instance, a shield volcano is composed mainly of (a)_____, while a composite volcano is composed mainly of (b)_____.

A. (a) basalt, (b) rhyolite

B. (a) rhyolite, (b) basalt

C. (a) andesite, (b) basalt

D. (a) basalt, (b) andesite

E. none of the above combinations

15. (a)_____ forms from (b)_____ magma and is the lightest colored extrusive igneous rock.

A. (a) Basalt, (b) mafic

B. (a) Basalt, (b) felsic

C. (a) Rhyolite, (b) felsic

D. (a) Rhyolite, (b) mafic

E. none of the above combinations

16. The grain size of igneous rocks is correlated to cooling rates. The (a)_____ the magma cools, the (b)_____ the grains. Thus obsidian, often called volcanic glass, formed from magma that cooled (c)_____.

A. (a) faster, (b) smaller, (c) very fast

B. (a) slower, (b) larger, (c) very fast

C. (a) faster, (b) smaller, (c) very slow

D. both A and B ((note: was ≥A and C≤ on your test copy, but changed to ≥A and B≤ before the test)

E. none of the above combinations

17. Rocks are melted in nature by a/an (a)_____ in temperature and/or a/an (b)_____ in pressure.

A. (a) increase, (b) increase

B. (a) decrease, (b) decrease

C. (a) decrease, (b) decrease

D. (a) increase, (b) decrease

E. none of the above combinations

18. Increases in temperature in the earth can be caused by:

A. the geothermal gradient

B. radioactivity

C. friction

D. hot spots

E. all of the above

19. Geologists use Bowenπs reaction series to explain:

A. how a magma crystallizes

B. the grain size in metamorphic rocks

C. how a rock melts

D. both A and C

E. none of the above

20. In a cooling magma, _____ would crystallize first.

A. biotite

B. amphibole

C. pyroxene

D. olivine

E. none of the above

21. If a granite is heated, (a)_____ would melt before (b)_____.

A. (a) quartz, (b) biotite

B. (a) biotite, (b) quartz

C. (a) olivine, (b) amphibole

D. (a) olivine, (b), pyroxene

E. none of the above combinations

22. Magma generally evolves from _____ in composition.

A. felsic to mafic

B. mafic to felsic

C. low in Fe to high in Fe

D. high in Si to low in Si

E. none of the above

23. Which of the following processes does not require Bowenπs reaction to explain how it works?

A. crystal settling

B. assimilation

C. partial melting

D. magma mixing

E. none of the above

24. If a mafic magma crystallizes deep in the earth, it would form (a)_____, but if it erupted at the earthπs surface it would form (b)____.

A. (a) rhyolite, (b) granite

B. (a) granite, (b) rhyolite

C. (a) basalt, (b) gabbro

D. (a) gabbro, (b) basalt

E. none of the above

25. (a)_____ is the most common intrusive igneous rock, and (b)_____ is the most common extrusive igneous rock.

A. (a) Granite, (b) basalt

B. (a) Basalt, (b) granite

C. (a) Shale, (b) schist

D. (a) Schist, (b) shale

E. none of the above combinations

26. (a)_____ is both lighter in color and lighter in weight than (b)_____. This is true because of the two, (b)_____ contains more iron, and iron has the largest atomic weight of the common rock-forming elements.

A. (a) Granite, (b) gabbro

B. (a) Rhyolite, (b) basalt

C. (a) Andesite, (b) basalt

D. all of the above combinations

E. none of the above combinations

27. The common extrusive and intrusive rocks can be added to Bowenπs reaction series. When this is done, (a)_____ is/are on the top associated mainly with olivine and Ca-feldspar and (b)_____ is/are on the bottom associated mainly with quartz, muscovite, and K-feldspar.

A. (a) rhyolite,(b) gabbro

B. (a) granite, (b) basalt

C. (a) basalt and granite, (b) gabbro and rhyolite

D. (a) basalt and gabbro, (b) rhyolite and granite

E. none of the above combinations

28. Most commonly, (a)_____ forms at diverging plate boundaries, while (b)_____ forms where a continental plate collides with an oceanic plate.

A. (a) basalt, (b) andesite

B. (a) basalt, (b) granite

C. (a) andesite, (b) granite

D. (a) granite, (b) basalt

E. none of the above combinations

29. In my sediment-sedimentary rock cycle, I included which of the following:

A. weathering

B. erosion & transportation

C. deposition

D. lithification & crystallization

E. all of the above (note: was ≥none of the above≤ on your test copy, but changed to ≥all of the above≤ before the test)

30. Rocks break down into sediment in two broad ways. (a)_____ deals with rock breakdown by applied stress such as that caused by changes in pressure and temperature, while (b)_____ refers to minerals dissolving in solutions, often rainwater.

A. (a) Chemical weathering, (b) mechanical weathering

B. (a) Lithification, (b) crystallization

C. (a) Crystallization, (b) lithification

D. (a) Mechanical weathering, (b) chemical weathering

E. none of the above combinations

31. Geologists often use rounding of sediments to gain some idea of how far a material was transported. For instance, a material that was transported a long distance by water often becomes:

A. very angular

B. well rounded

C. blocky

D. rectangular shaped

E. none of the above

32. Sedimentary structures _____, and they can thus be used to help determine the so-called environment of deposition.

A. are caused by directed stress applied to a rock

B. form during lithification

C. form during sedimentation

D. are caused by non-directed stress fields

E. none of the above combinations

33. Two common types of bedding occur in sedimentary rocks: horizontal and cross. In general, horizontal bedding occurs in (a)_____ and cross bedding occurs in (b)_____

A. (a) rivers, (b) lakes

B. (a) flowing water, (b) still water

C. (a) still water, (b) flowing water

D. (a) sand dunes, (b) rivers

E. none of the above combinations

34. Mud cracks are a common sedimentary structure and indicate sediment was deposited at the:

A. bottom of an ocean

B. bottom of a lake

C. surface of a glacier

D. land/water interface (e.g., a lake)

E. none of the above

35. Sediment sorting can be used as an aid to determine what transported the material. For instance, well-sorted sediment may have been deposited by (a)_____, whereas poorly-sorted sediment may have been deposited by (b)_____.

A. (a) wind and water, (b) a glacier

B. (a) a glacier, (b) wind and water

C. (a) a glacier, (b) water

D. (a) a glacier, (b) wind

E. none of the above combinations

36. Sedimentary rocks are classified based on their (a)_____ (i.e., minerals present) and (b)_____ (i.e., the size of the grains in the rock), and two of the main classes are (c)_____ which are mainly made by lithification of sediments and (d)_____ which are mainly formed by crystallization.

A. (a) composition, (b) texture, (c) sandstone, (d) limestone

B. (a) composition, (b) texture, (c) shale, (d) schist

C. (a) texture, (b) composition, (c) clastics, (d) carbonates

D. (a) composition, (b) texture, (c) clastics, (d) carbonates

E. none of the above combinations

37. Quartz is more common in sedimentary rocks than feldspars, even though there are more feldspars than quartz in the earthπs crust. This is so because feldspars undergo (a)_____ weathering when exposed to water and from (b)_____ minerals.

A. (a) mechanical, (b) clay

B. (a) mechanical, (b) calcite

C. (a) chemical, (b) calcite

D. (a) chemical, (b) clay

E. none of the above combinations

38. In sedimentary rocks there are three sizes of grains: (a)_____ is/are greater than 2 mm, (b)_____ is/are between 1/16 mm and 2 mm, and (c)_____ is/are less than 1/16 mm.

A. (a) gravel, (b) silt, (c) mud

B. (a) rocks, (b) silt, (c) mud

C. (a) rocks, (b) silt, (c) clay

D. (a) gravel, (b) sand, (c) mud

E. none of the above combinations

39. The smallest size fraction (the one below 1/16 mm) is broken into two size fractions: (a)_____, the larger one, and (b)_____ the smaller one. A geologist (with bad teeth) can tell the difference between these sizes because the larger one tastes gritty.

A. (a) silt, (b) mud

B. (a) clay, (b) silt

C. (a) silt, (b) clay

D. (a) clay, (b) mud

E. none of the above combinations

40. In the classification scheme for igneous rocks, we basically divided the rocks into two groups: phaneritic, with minerals that could be seen, and the aphanitic, with minerals that could not be seen. Based on the sedimentary grain sizes, phaneritic rocks would be:

A. gravel sized

B. sand sized

C. sand and/or gravel sized

D. mud sized

E. none of the above

41. A sedimentary rock made from angular sized gravel is called a/an:

A. coquina

B. oolitic

C. breccia

D. conglomerate

E. none of the above

42. Coal forms from large masses of organic material. As the organic material turns to rock, its (a)_____ content goes up and its (b)_____ content goes down as temperature, pressure, and time increase.

A. (a) water, (b) carbon

B. (a) carbon, (b) water

C. (a) water, (b) heat

D. (a) organic, (b) heat

E. none of the above combinations

43. Metamorphic rocks form from alteration of existing rocks:

A. after they weather to sediment

B. after they melt

C. that are exposed at the earthπs surface

D. in the solid state

E. none of the above

44. Metamorphic rocks from by increases in temperature and pressure. Their shapes are also controlled by the type of stress that formed them. For instance, _____ makes objects smaller but does not change their shape (e.g., a circle would remain, only get smaller).

A. normal stress

B. confining pressure

C. directed stress

D. shear stress

E. none of the above

45. Geothermal and geopressure gradients vary as a function of plate boundary types. Diverging plate boundaries are locations of (a)_____, while converging plates boundaries are locations of (b)_____.

A. (a) higher T, lower P, (b) lower T, higher P

B. (a) lower T, lower P, (b) higher T, higher P

C. (a) lower T, higher P, (b) higher T, lower P

D. (a) higher T, higher P, (b) lower T, lower P

E. none of the above combinations

46. Different minerals are present in metamorphic rocks because of:

A. the original rock composition

B. the P-T conditions of metamorphism

C. magma composition

D. both A and B

E. none of the above

47. Foliated metamorphic rocks are formed by:

A. metamorphism of a quartz sandstone

B. melting of a shale

C. non-directed stress

D. directed stress

E. none of the above

48. During metamorphism of shale, (a) _____ is the first rock formed, followed by phyllite which, with increasing pressure, temperature, and time will convert to (b)_____ and finally gneiss.

A. (a) basalt, (b) granite

B. (a) sandstone, (b) quartzite

C. (a) schist, (b) slate

D. (a) slate, (b) schist

E. none of the above combinations

49. The guest lecturer on Monday before the test talked about Mt. St. Helens and gave the sequence of events in September and October of this year, which are (from oldest to youngest):

A. earthquakes, surface deformation, steam eruption, magma eruption

B. surface deformation, earthquakes, magma eruption

C. magma eruption, earthquakes

D. steam eruptions, earthquakes

E. none of the above

50. I have made sure that my ID and name are correctly entered on the scan sheet, I will take the test with me when I leave, and I have answered all the questions on the test and entered them on the scan sheet.

A. yes

B. no