GEOLOGY 1001
Second Exam.
falls? a. pyroxene to olivine b. olivine to pyroxene c. Ca-rich plagioclase to Na-rich plagioclase d. mica to amphibole e. b and c
2. Zoned plagioclase feldspars show _____ rich centers and _____ rich rims.
a. Na, Ca b. Fe, Mg c. Ca, Fe d. Ca, Na e. none of the above.
4. A discordant tabular igneous pluton is called a:
a. vesicle b. sill c. dyke d. batholith e. none of the above
5. A very dangerous phenomenon related to volcanism that can lead to severe loss of life is called:
a. vesicle b. xenolith c. pyroclastic flow d. graded bedding e. none of the above.
6. A shield volcano is basically made up of ______ lava flows.
a. andesitic b. granitic c. felsic d. basaltic e. ultramafic
7. A(n) ______ volcano is formed by eruption of intermediate type of magma:
a. shield b. cinder cone c. composite (strato) d. rhyolite e. andesite
8. What type of magmatism (lavas) are associated with divergent plate boundaries?
a. ultramafic b. mafic c. intermediate d. felsic e. none of the above
9. A circular depression formed from fissure eruptions, by gravitational collapse into an empty
magma chamber is called a:
a. phoenix b. pyroclastic flow c. caldera d. strato volcano e. none of the above
10. The volcanoes in Hawaii, formed from mafic lavas are of the ____ variety.
a. composite (strato) b. cinder cone c. volcanic dome d. shield e. none of the above
11. What type of volcanic rock is commonly formed at transform fault boundaries?
a. andesite b. gabbro c. basalt d. shale e. none of the above
12. The viscosity of lavas decreases with:
a. decreasing temperature b. increasing temperature c. increasing silica content d. a and c e. b and c.
13. Massive volcanic eruptions can lead to global climatic changes.
a. True b. False
14. Features associated with lava flows include:
a. vesicles b. xenoliths c. sorting d. a and b e. a, b and c.
15. In Bowen’s discontinuous reaction series, the minerals formed as the temperature falls, show
increasing polymerization of the SiO 4 tetrahedra. a. True b. False
a. calcite b. halite c. sylvite d. gypsum e. pyrite
17. Strata that dip quite steeply from the horizontal in a sequence of sedimentary beds that are otherwise horizontal, display:
a. sorting b. graded bedding c. cross bedding d. turbidites e. fans.
18. Which is the correct sequence for the formation of a clastic sedimentary rock ?
a. weathering of rock, transport, deposition, lithification
b. lithification, weathering of rock, transport, deposition
c. weathering of rock, deposition, lithification, transport
d. transport, deposition, lithification, weathering of rock
19. Which of the following sedimentary rocks will show the maximum amount of compaction
during lithification? a. sandstone b. slate c. shale d. bauxite e. laterite.
20. Which of the following silicate minerals is most resistant to chemical weathering?
a. iron (hydr)oxide b. feldspar c. quartz d. calcite e. olivine
21. The most common type of sedimentary rock is: a. shale b. slate c. sandstone d. limestone e. halite
22. Poorly sorted detrital sediments contain grains of almost exactly the same size.
a. True b. False
23. Which of the followingminerals is most resistant to chemical weathering?
a. halite b. olivine c. feldspar d. quartz e. iron (hydr)oxide
24. The two most common detrital products of chemical weathering are:
a. quartz and olivine b. clay minerals and calcite c. quartz and clay minerals d. calcite and quartz
25. Physical weathering includes:
a. action of (tree) roots b. freezing and thawing c. lineation d. a and b. e. a, b and c.
26. Which is the most common type of biochemical sedimentary rock?
a. halite b. gypsum c. limestone d. marble e. shale
27. In which type of climate is chemical weathering least severe?
a. cold and wet b. cold and dry c. hot and wet d. hot and heavy
28. Which of the following minerals disappears without a trace during chemical weathering?
a. olivine b. feldspar c. quartz d. calcite e. iron oxide.
29. A common mineral in rocks that survives chemically unchanged through weathering to form an important part of detritus is:
a. feldspar b. calcite c. olivine d. halite e. quartz
30. Which of the following minerals must be present in a metamorphic rock in order for it to develop foliation?
a. quartz b. amphibole c. mica d. olivine e. pyroxene
31. Which of the following is the correct sequence for displaying decrease in intensity (grade) of metamorphism:
a. schist, gneiss, slate b. gneiss, schist, slate c. gneiss, slate, schist d. slate, schist, gneiss e. schist, slate, gneiss
32. Which of the following is a good index mineral in metamorphic rocks?
a. quartz b. iron oxide c. garnet d. feldspar e. pyroxene
33. A rock that is metamorphosed to the mphibolite facies reached a peak temperature of about:
a. 450 o C b. 100 oC c. 650 o C d. 800 oC e. 1000 oC
34. The most noticeable changes in the texture and mineralogy of a regional metamorphic rock, occurs during the retrogressive phase.
a. True b. False
35. Blueschist facies rocks are commonly found near what type of plate boundary?
a. divergent b. convergent c. transform fault d. a and c. e. b and c.
36. Directed pressure during regional metamorphism leads to what type(s) of rock texture?
a. lineation b. sorting c. foliation d. hornfels e. a and c.
37. The average value of the geothermal gradient is about :
a. 30 oC/m b. 3 oC/km c. 30 oC/km d. 30 oC/cm e. 300 oC/ km
38. Which of the following metamorphic shows no foliation/lineation?
a. granulite b. greenschist c. hornfels d. a and c e. a, b and c
39. Which of the following is a regional metmorphic rock?
a. shale b. andesite c. hornfels d. sandstone e. none of the above.
40. Which of the following is not a metamorphic rock?
a. slate b. shale c. quartzite d. schist e. marble
41. A surface separating tilted sedimentary rocks (below) from horizontal sedimentary rocks
(above) is called a disconformity. a. True b. False
42. Which of the following places the Periods in the right order from youngest to oldest?
a. Tertiary, Cambrian, Triassic b. Juarssic, Ordovician, Permian c. Quaternary, Cretaceous, Silurian d. Devonian, Carboniferous, Permian
e. none of the above.
43. The half-life of the potassium-argon dating system is about:
a. 6000 y b. 4.5 b.y. c. 1.3 b.y. d. 600 m.y. e. 200 m.y.
44. A sandstone bed is thought to be of Permian age. What dating system would yield its correct radiometric age?
a. Radiocarbon b. Potassium-Argon c. Uranium-Lead d. b and c e. none of the above.
45. A mineral contains 300,000 atoms of the daughter and 20,000 atoms of the parent material. If the system has a half-life of 70,000 years, the age of the mineral is ___ thousand years.
a. 70 b. 140 c. 210 d. 280 e. 350
46. The Paleozoic and Mesozoic Eras lasted about _____ and ____ m.y. respectively.
a. 550, 250 b. 300, 185 c. 100, 300 d. 300, 65 e. 185, 300
47. Important principles involved in relative dating techniques include the laws of:
a. original horizontality b. superposition c. faunal correlation d. radioactivity e. a, b and c
48 and 49. See Figure below.
48. Which beds could contain dinosaur fossils?
a. A thru L b. B thru K c. C thru K d. D thru J e. F thru J.
49. The surface marked “O” is called a(n):
a. angular unconformity b. nonconformity c. disconformity d. nonconformist e. graded bed.
50. Pangaea began to beak up about ____ m.y. ago.
a. 2000 b. 20 c. 200 d. 400 e. 600
51. An explosion of life forms at the Earth’s surface took place about _____ m.y. ago.
a. 4500 b. 550 c. 950 d. 250 e. 5
52. A good index fossil is called:
a. crawfish b. vesicle c. trilobite d. garnet e. glaucophane
53. The best method of dating “events” in the Mississippi delta over the last ~10 k.y. should be
the ___ method. a. Radiocarbon b. Potassium-Argon c. Uranium-Lead.
54. Marble is a metamorphic rock formed from:
a. sandstone b. limestone c. halite d. granite e. basalt