GS1100  Principles of Geology (section 2)

2007 Fall Mid-Term Test

 

Make sure you have marked your name and student ID correctly on the provided answer sheet. Turn in your answer sheet to your Lab TA when you are done for him to check your name and ID number.  Note that the choices A, B, C, D in the question sheet correspond to 1, 2, 3, 4 on the answer sheet. Be careful not to mark “5” for your “Ds”.

 

Multiple Choices (chose the correct or the best answer)

 

1.  Which of the following best defines a mineral and a rock?

A) A rock has an orderly, repetitive, geometrical, internal arrangement of minerals; a mineral is a lithified or consolidated aggregate of rocks.

B) A mineral consists of its constituent atoms arranged in a geometrically repetitive structure; in a rock, the atoms are randomly bonded without any geometric pattern.

C) In a mineral the constituent atoms are bonded in a regular, repetitive, internal structure; a rock is a lithified or consolidated aggregate of different mineral grains.

D) A rock consists of atoms bonded in a regular, geometrically predictable arrangement; a mineral is a consolidated aggregate of different rock particles.

 

2. Which of the following is not a mineral?  

A) olivine              B) limestone                         C) calcite                                D) quartz

 

3. Which geologic concept is described by "the present is the key to the past"?

A) biblical prophesy            B) uniformitarianism                         C) Aristotelian logic            D) catastrophism

 

4. The average thickness of the continental crust is about

A) 35-40 km         B) 100-200 km                        C) 1000-2000 km                    D) 5-10 km

 

5. In correct order from the center outward, Earth includes which layers?

A) core, inner mantle, outer mantle, crust        B) inner core, outer core, mantle, crust

C) inner core, crust, mantle, hydrosphere        D) core, crust, mantle, hydrosphere

 

6.  The tectonic plates

A) are the outermost shell of the solid Earth.                                  B) are a rigid, solid layer about 100 km thick

C) includes the crust and the uppermost mantle                            D) all of the above

 

7. At mid-ocean ridges, two plates are 

A) moving towards each other.                         B) moving away from each other.                    

C) sliding along each other.                               D) stationary. 

 

8.  According to Plate Tectonics theory, most active volcanoes occur

A) on continents.                                                 B) in large tectonic plates.

C) along plate boundaries.                                 D) randomly over continents.

 

9.  What are the two most abundant elements in the Earth’s crust?

A) iron and magnesium                       B) oxygen and silicon        

C) nitrogen and oxygen                      D) silicon and calcium

 

10.  Atoms of the same element (oxygen, for example) have the same number of __________.

A) electrons in the nucleus                                                B) protons in the nucleus

C) neutrons in the outer nuclear shell                              D) electrons in the valence bond level

 

11.  In table salt (NaCl), sodium and chlorine atoms bond by

A) sharing the electrons in their outer shells.

B) transferring an electron in the outer shell of the sodium atom to the outer shell of the chlorine atom.

C) having valence electrons freely migrating among the ions of sodium and chlorine.

D) all above.

 

12.  What mineral is the hardest known substance in nature?

A) graphite                            B) native gold                       C) diamond                            D) muscovite

 

13. Why is basalt finer grained than gabbro?

A) gabbro formed from quick cooling of magma.  

B) basalt formed from quick cooling of magma.

C) basalt has a mafic composition.

D) gabbro has a mafic composition.

 

14. Visible quartz and potassium feldspar grains are the main constituents in a ____________.

A) granite                             B) gabbro                              C) basalt                                D) rhyolite

 

15.  Which of the following minerals would crystallize early from a cooling silicate magma?

A) biotite                               B) quartz                                C) olivine                               D) muscovite

 

16. Magma generation in subduction zones are mainly caused by

A) releasing of water and volatiles from the subducting plate

B) pressure release in the subducting plate

C) temperature increase in the surrounding mantle

D) all above

 

17.  Which of the following tend to increase the explosive potential of a magma body beneath a volcano.  

A) High viscosity and dissolved gas

B) High viscosity; low dissolved gas content

C) Low silica content, low viscosity

D) Low viscosity; low dissolved gas content

 

18.  Eruptions dominated by basaltic lava flows typically form what type of volcanoes?

A) composite                                        B) stratospheric

C) cinder cone                                      D) shield

 

19. Why do magmas rise toward Earth's surface?

A) Magmas are more viscous than solid rocks in the crust and upper mantle.

B) Most magmas are richer in silica than most crustal and upper mantle rocks.

C) Magmas, being melts and having gases, are less dense than the adjacent solid rock.

D) magmas have higher content of pyroxenes than the surrounding rocks.    

 

20. Which of the following is NOT a process of physical (mechanical) weathering?

A) Frost wedging

B) unloading

C) thermal expansion

D) dissolution  

 

21. Which of the following silicate minerals are most resistant to chemical weathering?

A) quartz               B) olivine               C) hornblende                       D) potassium feldspar        

 

22. In the soil profile, the A horizon

A) is located below the O horizon                                     B) is called the zone of leaching

C) is part of the “top soil”                                                  D) all above

 

23.  What is probably the single most important, original, depositional feature in sedimentary rocks?

A) sizes of the sand grains

B) degree of lithification

C) bedding or stratification

D) compaction of the mud and clay

 

24.  What is the main difference between a conglomerate and a sedimentary breccia?

A) Breccia clasts are angular; conglomerate clasts are rounded.

B) A breccia is well stratified; a conglomerate is poorly stratified.

C) Breccia clasts are the size of baseballs; conglomerate clasts are larger.

D) Breccia has a compacted, clay-rich matrix; conglomerate has no matrix.

 

25.  Detrital sedimentary rocks are classified (named) based on the _________

A) colors of the cementing minerals

B) grain sizes of the detrital particles

C) compositions of soluble minerals

D) degree of compaction and lithification

 

26.  Flint, chert, and jasper are microcrystalline forms of __________.

A) quartz; (SiO2)                                                 B) hematite (Fe2O3)

C) halite (NaCl)                                                     D) calcite (CaCO3)

 

27. Which of the following is the most common type of chemical sedimentary rock.

A) Limestone                                                        B) Chert

C) Phosphate rock                                               D) Quartz sandstone

 

28. Which of following sedimentary rocks indicate long-distance transportation of the sediements?

A) quartz sandstone

B) breccia

C) arkose (sandstone with lots of feldspar particles)

D) none of above

 

29.  Which of the following forms at the highest grade of regional metamorphism?

A) gneiss                                                               B) schist

C) slate                                                                   D) phyllite

 

30.  What major change occurs during metamorphism of limestone to marble?

A) calcite grains recrystallize to larger and interlocked grains.

B) clays crystallize to micas, forming a highly foliated, mica-rich rock

C) limestone grains react to form quartz and feldspars

D) calcite grains are dissolved away leaving only marble crystals

            

31. What type of foliation results from the parallel alignment of abundant, coarse-grained, mica flakes in a metamorphic rock?

A) schistosity                                                       B) gneissic banding

C) slaty cleavage                                                  D) phyllitic structure

 

32. Metamorphic rocks can form from

A) sedimentary rocks          B) igneous rocks                  C) metamorphic rocks                          D) all above.

 

33. For undisturbed, horizontal strata of sedimentary rocks, their age

A) increases from top to bottom

B) decreases from top to bottom

C) can be determined from their color

D) is the same

 

34. What makes a good index fossil?

A) big and easy to see in the field

B) with a hard shell that can be easily preserved

C) spans over a long geological time period

D) widespread geographically and limited to a short span of geological time. 

 

35. An igneous rock contains a radioactive isotope that has a half-life of 10 million years. Careful analysis shows that only one quarter of the original concentration of the parent isotope is left. How old is this igneous rock?

A) 5 million years old          B) 20 million years old                       C) 40 million years old         D) 2.5 million years old

 

36. Which of the geological era is the youngest in the geologic time scale?

A)  Precambrian.                   B)  Mesozoic.                        C) Paleozoic.                         D) Cenozoic.

 

37. Lateral offset in drainage lines is commonly associated with

A) normal faults.                                  B) reverse faults.                 

C) thrust faults.                                    D) strike-slip faults.

 

38. Ductile deformation become important when

A) the temperature is hign

B) the confining pressure is high

C) deformation happens slowly

D) all above

 

39. In an structural basin, the youngest strata is found

A) at the center of the basin

B) on the margins of the basin

C) half-way between the center and the margins of the basin

D) beneath the older strata.

 

40. Which statement best describes motion on a normal fault?

A) The hanging wall block moved downward relative to the footwall block.

B) The hanging wall block moved upward relative to the footwall block.

C) The hanging wall block moved horizontally relative to the footwall block.

D) Faults are simple breaks in the crust along which no movement has occurred.