PracticeExam3Geology3

PracticeExam3Geology3 - Test 3 Geology 101 Fall 2007...

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Unformatted text preview: Test 3 Geology 101 Fall 2007 Instructor: Dr. Andrew Hajash Name /0/ 7957‘3 070?”); scantron after finishing test Mark answers on test first, transfer answers to RETURN TEST and SCANTRON (with UIN) DO NOT put UIN on this test 1) In which setting would regional metamorphism be most likely? A) at shallow depths below an oceanic ridge or rift zone B) at shallow depths beneath the seafloor where water pressures are immense C) at great depths in the crust where two continents are colliding D) at shallow depths along major transform faults in the continental crust 2) Which one of the following best describes the mineralogy of detrital or clastic sedimentary rocks? A) mostly those at the top of Bowen's reaction series. B) Mostly calcite, with some dolomite and olivine C) mostly calcite, gypsum, and halite D) mostly quartz and clay minerals. E) Mostly amphiboles and biotite and other anyhdrous minerals 3) According to the movie "Mystery of the Megaflood," what caused the Megaflood? A) the Columbia River was suddenly diverted into this valley by subduction of the Pacific plate B) the sudden release of water from a large lake formed when a river was dammed by a glacier C) outpouring of many basaltic lava flows, part of the Columbia River Basalts D) the failure of a large earthen dam built on the Columbia river by early inhabitants E) the wholesale rapid melting of large glaciers the area 4) Which one of the following statements is true? A) Older features cut across younger features B) A dike is always older than the rock it intrudes C) The law of superposition applies to all types of rocks D) In general, in undeformed sedimentary rocks, older rocks are overlain by younger rocks 5) According to the movie "Mystery of the Megaflood," approximately how many megafloods occurred in this area? A) only 1 B) many megafloods ( 20 —30) C) 2 or 3 6) Which one of the following best describes what happens to sediment particles as they are transported greater and greater distances in a river? A) They get smaller and more rounded B) They get rounder and larger as they roll along the bottom. C) The grains get slightly larger as they bounce along the bottom and adhere to other grains D) Nothing much happens to the grains as they are transported from the mountains to the oceans; however, once they reach the ocean, the salt water causes them to swell. E) The grains get more angular as they break into smaller pieces. 1) 2) 4) 7) According to the movie "Mystery of the Megaflood," what caused the long horizontal marks on 7) the hillsides near Missoula Montana? A) outpouring of many basaltic lava flows, part of the Columbia River Basalts B) wave-cut "terraces" along the shore of an ancient lake C) the movement of a glacier through the area D) normal river sediments deposited slowly over a long period of geologic time E) flood-related sediments deposited rapidly from a mega flood 8) Which one of the following statements is false about sedimentary rocks? 8) A) they are deposited at or near the earth's surface B) they are the most abundant rock type (by volume) in the crust of the Earth C) they are the most common rock type exposed on the surface of the Earth D) most are either limestones, sandstones, or mud rocks (silts and shales) E) they contain most of the Earth's energy resources used by man today 9) Which of the following sedimentary rocks would you expect to have originally been deposited 9) by fast-moving streams such as those on alluvial fans? A) mudstone B) graywacke C) oolitic limestone D) conglomerate 10) Which of the following best characterizes the boundary between the Cambrian Tapeats 10) sandstone which lies unconformably on the Vishnu Schist in the Grand Canyon A) angular unconformity B) nonconformity C) disconformity 11) Which of the follow best represents a marine REGRESSION in the field? 11) A) shale overlain by sandstone overlain by arkose B) limestone overlain by shale overlain by sandstone C) sandstone overlain by shale overlain by limestone D) sandstone overlain by conglomerate overlain by breccia 12) How many of the following statements about regional metamorphism are correct? 12) 1. Takes place over a large geopraphic region (hundreds of miles) 2. Usually forms nonfoliated rocks 3. Takes place where the geothermal gradient is very high 4. Is usually associated with convergent plate margins where two continental masses collide. 5. Is caused primarily by hydrothermal fluids A) 1 B) 2 C) 3 D) 4 E) 5 13) Which type of sediment undergoes the most compaction as it lithifies to sedimentary rocks? 13) A) marine mud B) desert dune sand C) coarse gravel D) reef limestone 14) If the age of the Earth were scaled to one year, which one of the following best describes the 14) time the Earth was inhabited by dinosaurs? A) April through June B) March 4 through March 20 C) November 18 through November 30 D) December 13 through December 25 E) September through October 15) How many of the following about metamorphism are correct? 1. Mineral recrystallize to try to reach equilibrium 2. Some metamorphic rocks are non—foliated 3.Most contact metamorphism takes place where the geothermal gradient is high. 4. A slate has a higher degree of foliation than a schist 5. In general, the grain size of metamorphic rocks increase with increasing grade A) 1 B)2 C)3 D)4 E)5 16) Which of the following statements best characterizes the differences between confining pressure and differential stress? A) differential stress is like water pressure and is the same in all directions; confinihf pressure is directed (magnitute varies with direction) B) confining pressure is like water pressure and is the same in all directions; differential stress is directed (magnitude varies with direction) C) confining pressure is due only to water and differential stress is due only to the weight of the overlying rocks D) confining pressure is due to the weight of the overlying rocks and differential stress is caused by water pressure from dehydration reactions. 17) Which one of the following best describes why the most abundant rocks at the Earth's surface are sedimentary? A) Most are made of minerals that are thermodynamically stable at surface conditions B) They form at the Earth's surface, often as a result of weathering , erosion and deposition. C) In the rock cycle, igneous and metamorphic rocks are converted to sedimentary rocks at or near the Earth's surface D) all of the above are true 18) As seawater evaporites, which of the following best represents the sequence of mineral precipitation, first to precipitate is on the left A) halite, gypsum, calcite B) calcite, gypsum, halite C) halite then calcite (no others precipitate) D) Halite, gypsum, anhydrite, calcite, bittem salts E) gypsum, calcite, halite 19) Which of the following is an essential characteristic of an index fossil? A) the organism only lived for a short period of geologic time B) the fossils are exceptionally abundant and well preserved C) the organism lived only in specific environments such as beaches or estuaries D) the fossils occur in deep-water marine sediments, but the organism actually lived in the sunlit, surface layer of the ocean 15) 16) 17) 18) 19) 20) Which of the following best describes the decay rate (atoms that decay per year) of a 20) radioactive isotope? — A) the decay rates are constant through time, allowing geologists to accurately date rocks B) the decay rates are not constant, they vary in an unpredictable fashion making the dates uncertain C) they are not constant but vary systematically through time. They decrease as the amount of parent decreases D) they are not constant but vary systematically through time. They increase as the amount of parent decreases 21) Which of the following statements best characterizes the changes in fluid chemistry as 21) seawater reacts with basaltic rocks at oceanic ridges? A) the chemistry changes very little as the water reacts with the rock. B) seawater evolves from a fluid rich in metals such as Fe, Mn, and Cu to a basic, oxygenated fluid rich in Na, C1, and Mg C) seawater evolves from an acidic, reducing fluid to a basic, oxygenated fluid rich in metals such as Fe, Mn, and Cu. D) seawater evolves from a basic, oxygenated fluid rich in Na, C1, and Mg to an acidic, reducing fluid rich in metals such as Fe, Mn, and Cu. E) seawater changes to fresh water and chemosynthetic bacteria at high temperatures. 22) Which of the following would retain the most detailed impressions of fossilized organisms? 22) A) very fine—grained volcanic ash deposited in an ancient lake B) an ancient, rainforest lateritic soil buried by basalt lava flows C) gravel and sand stream deposits laid down during flash floods D) quartz—rich sand deposited in shallow, beachfront environment 23) Why are quartz, calcite and clay minerals the most common minerals in sedimentary rocks? 23) A) They are all hydrous phases containing water, which is necessary for life at the surface. B) They are all carbonates, which is the main rock in calcite. C) They have been together since birth and enjoy each other's company. D) They are thermodynamically unstable under conditions at or near the surface of the Earth. E) They are thermodynamically stable under conditions at or near the surface of the Earth. 24) Nonclastic textures are common in which of the following sedimentary rocks? 24) A) cherty conglomerates B) sandstones C) boulder breccias D) limestones 25) The rock on the top of Mt. Everest is a shallow marine limestone deposited 200 million years 25) ago. What does this tell us about the geologic history of the Himalayas? A) 200 million years ago, the Himalayas did not exist. B) 200 million years ago, there was a high-alltitude lake at the top of the Himalayas. C) 200 million years ago, the ocean level was much higher than it is today so that limestones could be deposited at the top of the mountains D) Who cares what happened 200 million years ago? E) 200 million years ago, the Himalayas were located in the southern hemisphere under reversed magnetic polarity. 26) What is the source of natural carbon—14? 26) A) nuclear fission of the heavy, radioactive elements uranium and thorium B) cosmic ray collisions and neutron-capture involving atmospheric nitrogen C) leakage of radioactive gases from the liquid, outer core D) fusion of hydrogen and helium in the Sun and eruption of solar flares 27) Which of the following would exhibit sheared and mechanically fragmented rocks? 27) A) heating of shales and mudstones near a pluton B) fault movements at shallow depths C) regional metamorphism of pyroclastic volcanic rocks D) intense compression in a deep-seated, regional metamorphic zone 28) The ratio of parent to daughter isotopes in a radioactive decay process is 0.25. How many 28) half-lives have elapsed since the material was 100% parent atoms? A) between 2 and 3 B) betWeen l and 2 C) more than 3 D) less than 1 29) Which of the following best describes the age of end of the Permian (same age as the rocks on 29) the top of Grand Canyon)? A) 248 million years B) 65 million years C) 540 million years D) 15 billion years E) 4.5 billion years 30) Which of the following geologic observations would not bear directly on working out the 30) sequence of geologic events in an area? A) inclusions of sandstone in a granite pluton B) the feldspar and quartz contents of a granite C) an unconformity between a granite and sandstone D) a well-exposed dike of basalt in sandstone 31) What major change occurs during metamorphism of limestone to marble? 31) A) limestone grains react to form quartz and feldspars B) calcite grains grow larger C) clays crystallize to micas, forming a highly foliated, mica—rich rock D) calcite grains are dissolved away leaving only marble crystals E) amphibole breaks down to pyroxene plus water 32) What is the main difference between a conglomerate and a sedimentary breccia? 32) A) Breccia clasts are angular; conglomerate clasts are rounded. B) Breccia has a compacted, clay-rich matrix; conglomerate has no matrix. C) A breccia is well stratified; a conglomerate is poorly stratified. D) Breccia clasts are the size of baseballs; conglomerate clasts are smaller. 33) Which one of the following is the best geologic definition of a sand? A) Has grains that are between 2 mm and 1/16 mm. B) Must feel good between your toes C) Has grains that are greater than 2 mm. D) Has grains that are less that 1/ 16 mm. E) Must have well rounded grains of quartz that are between 2 mm and 1/ 16 mm. 34) Which one of the following is a feasible explanation as to why quartz sandstone is an excellent use of "uniformitarianism"? A) None of these statements make any sense to me; I want to go home Right N w! B) Layers of sand-size quartz—rich sediment found in a 10—million year old sanstone are virtually identical to layers at a modern beach, so in about 10 million years, the sandstone will weather into a beach environment. C) I should have taken biology instead of this stupid class! D) Comparison of modern beach sands to 10—million year old sandstones is pointless and in no way demonstrates the principles of uniformitarianism. E) Layers of sand-size quartz—rich sediment found today at the beach are virtually identical to layers in a 10-million year old sandstone, thus suggesting that the location of the sandstone was the location of a beach 10 million years ago. 35) Which one of the following statements best describes the decay of 19K40 to 18Ar40? A) decays by emission of one beta particle B) decays by nuclear capture of one electron C) decays by loss of one electron D) decays by loss of one alpha particle E) decays by capture of one neutron 36) Which one of the following accurately lists the relative order of geologic periods from oldest to youngest (periods may be missing in the sequence, but relative age must be correct) A) Silurian, Ordovician, Devonian, Pennsylvanian B) Cretaceous, Jurassic, Triassic, Tertiary C) Triassic, Jurassic, Pennsylvanian, Mississippian D) Era, Period, Epoch, Age, nothing, system, series, stage E) Cambrian, Silurian, Devonian, Permian 37) Which one of the following statements is correct (TRUE) concerning the K—Ar clock? A) assumes that there is no radiogenic argon in the system when the clock starts B) assumes that there is no Ca40 in the system C) can only date relatively young events, less than 60,000 years ago. D) assumes that the decay rate of potassium to argon is constant. E) assumes that the system or rock body behaves as an adiabatic system 38) When a radioactive isotope decays by electron capture, the electron . A) combines with a neutron in the nucleus, raising the mass number of the daughter isotope by one B) makes the daughter isotope into an ion with a charge of positive one C) combines with a proton in the nucleus; the atomic number of the daughter is one less than the parent D) makes the parent isotope into an ion with a charge of negative one 33) 34) 35) 36) 37) 38) 39) An disconformity is a . A) fault or fracture with younger strata above and older strata below B) fault or fracture with older rocks above and younger rocks below C) surface of erosion separating roughly parallel beds of sedimentary rock D) surface of erosion separating sedimentary beds that are NOT parallel to one another E) surface of erosion separating older igneous or metamorphic rocks below from younger sedimentary rocks above. 40) 92U235 decays to a stable daughter by the loss of 7 alpha particles and 4 beta particles. Which one of the following best describes the atomic weight and atomic number of this stable daughter? A) atomic weight =82 atomic number = 207 B) atomic weight = 82 atomic number = 206 C) atomic weight = 207 atomic number = 78 D) atomic weight = 207 atomic number = 82 41) Which of the following describes radioactive decay by beta particle emission? A) The daughter isotope has an atomic number one less than the parent and a mass number two less. B) The mass number of the daughter isotope is one more than the parent and both isotopes have the same atomic number. C) The daughter isotope has an atomic number two less than the parent and a mass number four less. D) The atomic number of the daughter isotope is one more than the parent; the mass numbers are the same. 42) Which characteristic is necessary for a sedimentary rock to have potential as a possible reservoir rock for oil or gas? A) elastic texture C) good stratification B) high porosity D) chemical origin 43) In central Mongolia, we found a east—west trending zone of high temperature, low pressure metamorphic rocks. Just to the north of this zone is a parallel zone of high pressure, low temperature metamorphic rocks. Which of the following is the best interpretation of the formation of these rocks. A) Formed at a eastward dipping subduction zone B) Formed at a westward dipping subduction zone C) Formed at a southward dipping subduction zone D) Formed at a continental rift zone by contact metamorphism E) Formed at a northward dipping subduction zone 44) Which one of the following best describes the sedimentary rocks of the great state of Texas? A) In general, they get younger moving from NW to SE. B) From East Texas to extreme south Texas, Tertiary sedimentary rocks dominate representing river, coastal and shallow marine deposition C) The hill country area of central Texas is composed mostly of shallow water marine limestones of Cretaceous age. D) all of the above are true 39) 40) 41) 42) 43) 45) Which of the following areas is the best environment for the formation of carbonate sediments 45) and lirnestones? A) High Island on the Texas Coast B) the Mississippi delta region C) Just off the northern California coast D) the Florida Keys and the Bahamas E) on the large shallow continental shelf in the Bering Sea behind the Aleutian Islands. 46) According to the movie "Mystery of the Megavolcano," who was the first person to link 46) volcanic eruptions with climate? A) George W. Bush with Jay Leno B) George Washington C) Enrico Fermi D) Al Gore E) Ben Franklin 47) According to the movie "Mystery of the Megavolcano," what was the first piece of evidence 47) discovered for something very unusual happening about 75,000 years ago? A) a large amount of volcanic ash was discovered in ice cores from Greenland B) A Large Igneous Province was discovered in the Indian Ocean. C) Ice cores from Greeland indicated that a very large amount of H2504 was in the atmosphere at that time D) none of the above E) investigations of tree ring data indicated a very hot climate at that time ' 48) According to the movie "Mystery of the Megavolcano," what was the primary factor that 48) initiated the ice age after the mega eruption? A) the enormous amout of C02 gas emitted from the volcano formed carbonic acid in the atmosphere. B) the enormous amout of 502 gas emitted from the volcano formed sulfuric acid in the atmosphere. I _ ’ C)rla;va from the megavolcano flowed. into the sea caused theformationyof an unusually thick .Wate-vapor mists or clouds that limited solar input. D) enormous amount of volcanic ash emitted from the volcano .- . 49) I talked about "the melting of polar ice " as a possible cause of global marine transgressions. 49) What other mechanism did I talk about as a probablye cause of global marine transgressions and regressions? A) major changes in seafloor spreading rates at oceanic ridges B) formation of evaporite deposits of gypsum and salt C) changes in the magnetic field D) changes in the rate of influx of cosmic rays 50) If the sketch below represents cross bedding in a fossil sand dune, which way was the wind 50) blowing for area A. A) from left to right —9 B) from right to left e” efl = *A/é MAJ/P /4/?’Pr'\ Answer Key Testname: 101TEST3FALLO7 1) C V 2) D v 3) B / 4) D“ was“ 6) A w 7) B -/ 8) B -/ 9) Dv 10) 13v 11) B ~/ 12) B / 13) A w 14) D r 15) E w 16) B -/ 17) D/ 18) B M 19) A x 20) Ca 21) D~/ 22) A/ 23) E" 24) D“ 25) A/ 26) BM 27) B / 28) A/ 29) A‘/ 30) 13/ 31) B/ 32) A / 33) A¢ 34) E 1/ 35) 13/ 36) E/ 37) Av 38) C~’ 39) c/ 40) DJ 41) DJ 42) BM 43) c/ 44) D/ 45) l D" 46) \/ 47) DC / 48) q 6 -/ 49) DA V 5076/ ...
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This note was uploaded on 04/09/2008 for the course GEOL 101 taught by Professor Olinsky during the Spring '08 term at Texas A&M.

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PracticeExam3Geology3 - Test 3 Geology 101 Fall 2007...

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