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EAS 105A1_Midterm study exam_2008 1. A) B) C) D) The atomic number of an element indicates the number of _____. electrons in the outer shell protons in the nucleus neutrons in the nucleus excess charges 2. A) B) C) D) The density of most rocks is about 2-3 g/ccm 6 g/ccm 11.3 g/ccm 19.3 g/ccm 3. A) B) C) D) Evaporation of seawater will eventually produce a _____ sediment. clastic marine chemical glacial 4. A) B) C) D) In the second orbital shell, atoms strive to have ___ electrons. two four six eight 5. A) B) C) D) The sodium ion has a charge of _____. 1– 2– 1+ 2+ 6. A) B) C) D) Bonds formed by electron transfer between charged atoms are termed _____. covalent metallic ionic van der Waals Page 1 7. A) B) C) D) The facing stone of the HMTory building (the one you are in right now) is an Ordovician dolostone from Manitoba an Ordovician sandstone from Manitoba a Devonian limestone from the Rocky Mountains a Devonian dolostone from the Rocky Mountains 8. A) B) C) D) Geologist use the so-called acid test to aid in identification of dolomite apatite gypsum calcite 9. A) B) C) D) Siliceous oozes in the deep seas are often deposited by the accumulation of _____. feldspars diatoms clays fish 10. A) B) C) D) Diamond is a polymorph of graphite carbon soot coal 11. A) B) C) D) A hornfels is a(n) _____. brown sedimentary rock well-foliated, mica-rich rock product of an ash flow even-textured contact metamorphic rock 12. A) B) C) D) Sinkholes can 'swallow' dogs cars houses all of the above Page 2 13. A) B) C) D) Diapirs are important for xenocryst occurrences groundwater supply placer gold deposits nuclear waste disposal 14. A) B) C) D) The initial depositional stage in the formation of coal is _____. graphite lignite peat anthracite 15. A) B) C) D) Most of Alberta's oil is found in _________ . Devonian sandstones Cretaceous sands Jurassic sandstones Devonian reefs 16. A) B) C) D) Graded bedding results from a special type of transport by water ice mud wind 17. Where partial melting has taken place and the resultant melt is crystallized in with the original source metamorphic rocks, we term this _____. A) low-grade metamorphism B) a migmatite C) contact metamorphism D) metasomatism 18. A) B) C) D) Foliation within high-grade metamorphic rocks is known as _____. cleavage bedding jointing schistosity Page 3 19. Low-grade metamorphism refers to metamorphic changes that arise at _____ °C temperatures. A) 50–100 B) 100–200 C) 200–300 D) 300–500 20. A) B) C) D) The sedimentary precursor of a phyllite is _____. limestone arkose shale dolostone 21. A) B) C) D) The sedimentary precursor of a slate is _____. sandstone limestone dolostone shale 22. A) B) C) D) Gneiss is a rock with _____. weak foliation excellent sorting of crystals distinct layers of light and dark minerals abundant olivine 23. The first zone we encounter below the zone of burial metamorphism at a convergent plate boundary is the zone of _____. A) greenschist metamorphism B) cataclasis C) partial melting D) blueschist metamorphism 24. A) B) C) D) Changes that affect sediments after deposition and during lithification are termed _____. erosion diagenesis metamorphism sorting Page 4 25. A) B) C) D) The intermediate-grade metamorphism of a greenschist will produce _____. granite marble amphibolite muscovite schist 26. A) B) C) D) High-grade metamorphism of a shale will produce the assemblage _____. quartz + chlorite + muscovite + plagioclase chlorite + epidote + plagioclase + calcite quartz + biotite + garnet + sillimanite + plagioclase pyroxene + plagioclase + garnet 27. A) B) C) D) A rock containing ____ is probably metamorphic. kyanite halite K-feldspar olivine 28. Foliation developed during low-grade metamorphism of clay-rich sedimentary rocks is called _____. A) gneissosity B) schistosity C) slaty cleavage D) exfoliation 29. A) B) C) D) Metamorphism at temperatures above ~550° is termed _____. thermal low grade high grade dynamic 30. Changes that take place upon the cooling off after a metamorphic event would be classed as _____. A) prograde B) progressive C) retrograde D) retrogressive Page 5 31. A) B) C) D) One of the most common cements in sedimentary rocks is _____. silicon dioxide calcium carbonate iron sulfide calcium phosphate 32. A) B) C) D) The formation of thick peat deposits requires limited supply of _____. carbon dioxide nitrogen oxygen hydrogen sulfide 33. A) B) C) D) Lake waters can evaporate and thus precipitate _____. feldspar borax hematite pyrite 34. A) B) C) D) A sandstone with a high feldspar content is a(n) _____. arkose breccia felsite calcrete 35. A) B) C) D) Petroleum is generally derived from organic matter deposited in _____. inland swamps rivers the crystalline basement marine sediments 36. A) B) C) D) The dominant type of bonding within a gold nugget would be _____. van der Waals ionic covalent metallic Page 6 37. A) B) C) D) Mechanical weathering in the Sahara can be caused by _____. microseismic activity tree roots forest fires the crystallization of salts 38. A) B) C) D) A sediment with average grain size of 1 mm would be a _______. silt clay sand pebble gravel 39. A) B) C) D) Diamonds demonstrate what type of bonding? van der Waals ionic covalent metallic 40. During weathering of granites in the Sierra Nevada of California, thin shells of rock spall off the outcrops. This phenomenon is called _______. A) sloughing B) rock bursting C) conchoidal fracturing D) exfoliation 41. Strong chemical weathering takes place in regions with annual rainfalls exceeding ____ cm/yr. A) ~50 B) ~100 C) ~150 D) ~400 42. A) B) C) D) Lithification of a river gravel produces _____. sandstone conglomerate mudstone siltstone Page 7 43. Multiple cycles of erosion and deposition can result in a sediment composed almost entirely of _____. A) calcite B) quartz C) mica D) olivine 44. A) B) C) D) Chemical weathering would be most extreme in _____. Nevada New York Arkansas Cuba 45. A) B) C) D) Water-deposited sandstones often exhibit _____. graded bedding slumped bedding cross bedding varves 46. A) B) C) D) A rock dominated by 300-mm-diameter round clasts would be a _____. boulder conglomerate cobble conglomerate sandstone pebble conglomerate 47. A) B) C) D) Frost wedging is highly effective at temperatures in the range of ____ °C. 0 to 5 –5 to –10 –10 to –20 –20 to –30 48. When rocks that have been buried are exposed by erosion, structures develop that are known as _____. A) foliation B) cleavage C) joints D) faults Page 8 49. A) B) C) D) Chemical weathering is prevalent where there _____. are at least 30 days of frost is minimal plant growth is high precipitation and a hot climate is an arid, hot climate 50. A) B) C) D) The principal acidifying agent in groundwater is ___ acid. sulfuric nitric carbonic hydrochloric 51. A) B) C) D) Deposition of detritus produces a _____. chemical sediment talus dolostone clastic sediment 52. A) B) C) D) The basic building block for all silicate minerals is the _____. silicate tetrahedron metallic bond ionic bond chloride ion 53. A) B) C) D) Micas and clay minerals are ____ silicates. 3-D network double-chain sheet single-chain 54. A) B) C) D) Calcite may be attacked by carbonic acid to release _____. hydrogen ions and carbon dioxide calcium ions and bicarbonate ions oxygen ions and hydrogen ions carbon dioxide and calcium metal Page 9 55. A) B) C) D) The Mohs hardness of apatite is _____. 2 3 4 5 56. A) B) C) D) Garnets are commonly used as _____. electronic components abrasives electrical insulators ores of silicon 57. A) B) C) D) Amethyst is a purple variety of _____. pyroxene hornblende quartz amphibole 58. A) B) C) D) The constituent of magmas that is usually predominant is _____. H2O MgO SiO2 K2O 59. A) B) C) D) Gabbro contains about ____ percent SiO2. 40 50 60 70 60. A change in the chemical composition of a rock induced during metamorphism is termed _____. A) hydrothermal activity B) metasomatism C) cataclasis D) exsolution Page 10 61. A) B) C) D) The viscosity of erupting lavas is a function of ___ content. SiO2 K2O Al2O3 MgO 62. A) B) C) D) Natural gas may not form ____________ . from dead animals from dead plants during the liquid oil window in a well-oxygenated environment. 63. A) B) C) D) Zeolites are _____. a group of sulfides with high specific gravities similar in composition to feldspars, but contain water very similar to amphiboles with less Ca a group of sheet silicates related to micas 64. A) B) C) D) High-grade metamorphism of basaltic lava will produce the assemblage _______. chlorite + epidote + plagioclase + calcite quartz + chlorite + muscovite + plagioclase quartz + biotite + garnet + sillimanite + plagioclase pyroxene + plagioclase + garnet 65. A fine-grained, quartz-bearing igneous rock in which K-feldspar is a dominant phase is a(n) _____. A) granite B) rhyolite C) diorite D) andesite 66. A) B) C) D) Diagenesis involves two of the below differentiation compaction recrystallization Page 11 67. A) B) C) D) The coal mines in the Edmonton area are of Cretacous age Devonian age Tertiary age Jurassic age 68. A dark-colored, coarse-grained igneous rock that contains 55% pyroxene and olivine intergrown with plagioclase is a _____. A) granite B) diorite C) peridotite D) gabbro 69. This soil horizon is brown or reddish, enriched in clay and/or iron and aluminum hydroxides. It is the ____ horizon. A) E B) O C) A D) B 70. A) B) C) D) Volcanoes on the mid-Atlantic spreading center erupt _____. basalt andesite rhyolite dacite 71. A) B) C) D) Very rapidly cooled magmas produce _____. obsidian andesite scoria basalt 72. A) B) C) D) Rhyolites probably form by partial melting of _____. wet andesite dry dacite dry basalt wet granite Page 12 73. A) B) C) D) Lavas flow extremely slowly if their SiO2 contents exceed ____ percent. 40 50 60 70 74. A fine-grained pyroclastic rock with abundant fragments greater than 64 mm in diameter is termed a(n) _____. A) bomb B) agglomerate C) tephra D) lapilli tuff 75. A) B) C) D) Ignimbrites are deposited by _____. lahars pyroclastic flows fissure eruptions tephra cones Page 13