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earth science100
midterm study ch 1 - 7
| Question | Answer |
|---|---|
| Which group of minerals are the most abundant in the Earth's crust | silicates |
| The texture of an igneous rock ________. | records the rock's cooling history |
| Metamorphism is commonly associated with mountain building | True |
| In the silicon-oxygen tetrahedron there are more silicon atoms than oxygen atoms | False |
| Atoms of the same element, zinc for example, have the same number of | protons in the nucleus |
| Which one of the following is NOT true about mechanical weathering | does not affect metamorphic rocks |
| All silicate minerals contain which two elements | silicon, oxygen |
| Quartz is quite resistant to weathering and is an important component of sands in riverbeds and on beaches | True |
| Isotopes of the same element have the same mass number | False |
| The most abundant chemical sedimentary rock is | limestone |
| The strong tendency of certain minerals to break along smooth, parallel planes is known as | cleavage |
| ________ is a strong, parallel alignment of different mineral bands in a metamorphic rock | Foliation |
| As the rate of cooling increases, the size of the crystals that form | decreases |
| Which pair of minerals is most common in detrital sedimentary rocks | clay and quartz |
| All atoms of the same element have the same atomic number | True |
| Most limestone has a biochemical origin | True |
| The primary agent of contact metamorphism is | heat |
| Evaporites have a biochemical origin | false |
| Most minerals have a higher specific gravity than water | True |
| Which of the following best defines a mineral and a rock | 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 |
| The most unreliable (variable) diagnostic property of minerals such as quartz is | color |
| Rocks are aggregates of one or more minerals | True |
| An atom's mass number is 13 and its atomic number is 6. How many neutrons are in its nucleus | 7 |
| Which of the following is NOT one of the eight most common elements in Earth's crust | carbon |
| Detrital sedimentary rocks are classified (named) primarily on the basis of | particle size |
| Olivine and quartz are commonly found together in the same rock | False |
| Which of the following minerals is a silicate | feldspar |
| Which the following denotes the positively charged particles in an atom's nucleus | protons |
| Which one of the following is not true for minerals | they can be a liquid, solid, or glass |
| A mineral can be composed entirely of one element | True |
| All atoms of the same element have the same atomic number | True |
| Atoms that have an electrical charge due to a gain or loss of electrons are called | ions |
| Which of the following best describes bedded gypsum and rock salt | evaporites; chemical, sedimentary rocks |
| Detrital sediments would predominate in all of the following environments except | salt flat |
| Which of the following is correct for isotopes of the same element | the atoms have different numbers of neutrons and the same number of protons |
| Metamorphism can affect only sedimentary rocks | False |
| Glassy igneous rocks form when magma cools so slowly that mineral crystals cannot grow | False |
| The resistance of a mineral to abrasion is known as | hardness |
| One magma can produce several different igneous rocks having different mineral compositions | True |
| All minerals exhibit cleavage | False |
| Select the coarse-grained rock which is composed mainly of quartz and potassium feldspar from the list below | granite |
| This igneous texture is characterized by two distinctively different crystal sizes | porphyritic |
| What element is the most abundant in the Earth's crust by weight | oxygen |
| Which one of the following is an igneous rock | rhyolite |
| Electrically neutral atoms have equal numbers of electrons and protons | True |
| The ion at the center of a silicon-oxygen tetrahedron is surrounded by | 4 oxygen ions |
| Discharge is an important concept. What statement best describes stream discharge | It's a measure of how much water is moving past a certain location along the stream each second |
| Which part of a stream flows the fastest | Near the top |
| If an object at the top of a stream traveled 5.0 meters in 12 seconds, what would be its velocity | 0.42 m/s |
| At what depth should a velocity sensor be placed to estimate a stream's average velocity if it is 12.5 meters deep | 7.5 meters |
| Calcualte the discharge of a stream with a width of 8.8 meters, a depth of 0.75 meters and an average velocity of 0.13 m/s to two decimal places | 0.86 cu m/s |
| How many cubic meters are there in one cubic foot | 0.0283 |
| The source of heat for most hot springs is hot igneous material beneath the surface | True |
| More water is evaporated from the ocean than is returned to the ocean by precipitation | True |
| Loess consists mainly of silt-sized particles | True |
| A(n) ________ is likely to host a waterfall or steep rapids today | hanging valley |
| A fiord is a | drowned glacial trough |
| ________ is an irregular, usually thin till layer laid down by a retreating glacier | Ground moraine |
| Point bars are depositional features located along the outer banks of meander bends | False |
| Steppes are the driest of the true desert lands | False |
| Which of the following best describes how geysers erupt | with a slight reduction in pressure, water in a saturated, natural conduit suddenly boils, sending a plume of steam and hot water into the air above the vent |
| A ________ cross-valley profile is typical of canyons and valleys eroded and deepened by alpine or valley glaciers | U-shaped |
| Drumlins are | not found singly, but in clusters |
| At the head of a delta, the major channel splits into smaller channels that follow different paths to the sea. These smaller channels are known as | distributaries |
| A cirque represents an erosional feature formed in what was an important accumulation zone for snow and ice at the upstream head of a glacier | True |
| As its name implies, the water table is always very level (flat) | False |
| Loose, undisturbed particles assume a stable slope called the angle of repose | True |
| When water is pumped from a well, a depression is often produced in the water table. Such a depression is a(n) | cone of depression |
| At a bend in a river, the main erosion is | on the outside of the bend |
| A ________ forms when a block of ice is buried in drift and subsequently melts creating a pit | kettle |
| Which one of the following is NOT true of glaciers | exist only in the Northern Hemisphere |
| ________ is one of the two, major flow mechanisms in a glacier | Basal slip |
| A(n) ________ represents a former meltwater channel or tunnel in glacial ice that was filled with sand and gravel | esker |
| The single most important erosional agent is | running water |
| A broad accumulation of stratified drift deposited adjacent to the downstream edge of an end moraine is a | outwash plain |
| Which one of the following concerning artesian wells is NOT true | when the well penetrates the aquifer, the water rises in the well to the bottom of the overlying aquitard |
| ________ are characteristics of downcutting streams and a youthful stage of valley evolution | Rapids and lots of whitewater |
| Gravity plays an important role in all mass wasting events | True |
| The water table is | a boundary between saturated rock below and unsaturated rock above |
| Where is the world's largest ice sheet located today | Antarctica |
| The transfer of rock material down slope under the influence of gravity is termed | mass wasting |
| Desert pavement is the result of | deflation |
| Which one of the following applies to a valley glacier that lengthens (extends its terminus downslope) over a period of many years | accumulation exceeds wastage |
| Abrasion and plucking generally involve what part of a glacier | the basal, sliding zone |
| Running water is not an important erosional agent in deserts because rainfall is infrequent | False |
| Fiords are found exclusively along the coast of Norway | False |
| Blowouts are broad, shallow depressions excavated by deflation | True |
| If you were to examine the longitudinal profile of a typical river, you would probably find that the gradient is | steepest near the head |
| ________ is not part of the water cycle | Calcium carbonate dissolving in soil water and groundwater |
| One environmental problem associated with groundwater is land subsidence caused by withdrawal | True |
| Which of the following features characterize wide streams and valleys | natural levees; broad floodplains |
| Moraines are the only glacial deposits composed of till | False |
| Alluvium refers to stream deposits, mainly sand and gravel | True |
| Rapid surge movements of the Earth's tectonic plates offer a convincing explanation for the advances and retreats of the Pleistocene ice sheets | False |
| Desert and steppe lands cover about what percentage of Earth's land area | 30% |
| The formation of stalactites and stalagmites occurs in the zone of saturation | False |
| A ________ stream pattern is developed only on growing mountains like volcanoes or where the land surface is tectonically doming upward | radial |
| The term "drift" | means any sediments of glacial origin |
| The controlling force of mass wasting is | gravity |
| ________ generally constitutes the highest percentage of the annual sediment load moved by a stream | Suspended load |
| Glacial melting and calving occur in the zone of wastage | True |
| Earth's radius and surface area are slowly increasing to accommodate the new oceanic crust being formed at mid-ocean ridges | False |
| Which of the following energy sources is thought to drive the lateral motions of Earth's lithospheric plates | export of heat from deep in the mantle to the top of the asthenosphere |
| Seafloor spreading rates can be estimated if the geologic ages of the magnetic field reversals are independently known | True |
| ________ most effectively outline the edges of the lithospheric plates | Lines of earthquake epicenters |
| The oldest rocks of the oceanic crust are found in deep ocean trenches far away from active, mid-ocean ridges | True |
| The temperature below which magnetic material can retain a permanent magnetization is called the | Curie point |
| An extensive, late Paleozoic glaciation affected southern India, southern Africa and southeastern South America | True |
| ________ was an ancient reptile that lived in South America and Africa during the late Paleozoic | Mesosaurus |
| Cooler, older, oceanic lithosphere sink into the mantle at | subduction zones along convergent plate boundaries |
| The modern-day Red Sea is explained by plate tectonics theory because it is | a rift zone that may eventually open into a major ocean if Arabia and Africa continue to separate |
| Which of the following statements apply to the asthenosphere, but not the lithosphere | zone in the upper mantle that deforms by plastic flowage |
| In general, rocks of the oceanic crust are less dense than rocks of the continental crust | False |
| ________ was never proposed as evidence supporting the existence of Pangaea | Islands of Precambrian rocks along the Mid-Atlantic Ridge |
| The volcanoes of Hawaii are localized above a deep mantle hot spot; they are not part of the East Pacific oceanic ridge | True |
| The rate of seafloor spreading is, on the average, about one meter per year | False |
| The ________ is an example of an active, continent-continent collision | northward movement of India into Eurasia |
| Pull-apart, rift zones are generally associated with a ________ plate boundary | divergent |
| A transform plate boundary is characterized by ________ | a deep, vertical fault along which two plates slide past one another in opposite directions |
| Which of the following paleoclimatic evidence supports the idea of the late Paleozoic super continent in the Southern Hemisphere? | tillites (rocks formed by glaciers) in South Africa and South America |
| A very long-lived magma source located deep in the mantle is called a | hot spot |
| In the early part of the 20th century, ________ argued forcefully for continental drift | Alfred Wegener |
| Hawaii is the oldest island of the Hawaiian Island chain | False |
| The continental drift hypothesis was rejected primarily because Alfred Wegener could not | identify a mechanism capable of moving continents |
| Where would you drill to recover samples of the oldest basalts of the oceanic crust, which are Jurassic in age | oceanic side of the Aleutian trench |
| During various times in the geologic past, the polarity of Earth's magnetic field has been reversed | True |
| The lithosphere is defined as | a rigid layer of crustal and mantle material |
| Which of the following combinations should favor folding rather than faulting | high temperature and high confining pressure |
| The ________ in California is the boundary between the North American and Pacific plates | San Andreas strike-slip fault |
| Most of our knowledge about Earth's interior comes from | seismic waves |
| In a reverse fault, the hanging wall block moves up relative to the footwall block | True |
| A horst is ________ | an uplifted block bounded by two normal faults |
| Basin and range topography, like that in the western and southwestern United States, indicates that compressive folding is active today or was active very recently, geologically speaking | False |
| Which one of the following statements about the crust is NOT true | oceanic crust is enriched in potassium, sodium, and silicon |
| Oceanic crust is generally thicker than continental crust | False |
| Brittle deformation would be favored over plastic deformation in which of the following conditions | cooler temperatures |
| The Richter magnitude of an earthquake is based on the | amplitude of the largest seismic wave recorded |
| The record of an earthquake obtained from a seismic instrument is a(n) | seismogram |
| S waves can travel through solid and liquid media | False |
| On a seismogram, ________ will show the highest amplitudes | surface waves |
| In a ________ fault, the hanging wall block moves up with respect to the footwall block | reverse |
| The Mercalli Scale is a scale from | I to XII that rates the structural damage due to an earthquake |
| Large circular downwarped structures are called | basins |
| The mechanism by which rocks store and eventually release energy in the form of an earthquake is termed | elastic rebound |
| The ________ earthquake was accompanied by extensive fire damage | San Francisco, 1906 |
| The Black Hills of South Dakota are a good example of a(n) | dome |
| Approximately how much more energy is released in a 6.5 Richter magnitude earthquake than in one with magnitude 5.5 | 30 times |
| Accretionary wedges develop along subduction zones where sediments and other rocks are scraped off a descending plate and piled against the leading edge of the overriding plate | True |
| The ________ is (are) characterized by terrane accretion that has been active throughout most of Mesozoic and Cenozoic time | western margin of North America |
| The asthenosphere is located ________ | in the upper mantle |
| A ________ is a near surface, intrusive, igneous rock body that results from local inflation of a horizontal sill | laccolith |
| Most of the stratovolcanoes on Earth are located in a belt known as the | Ring of Fire |
| The largest igneous intrusive body is called a(n) | batholiths |
| Volcanism along divergent plate boundaries where seafloor spreading is occurring produces rocks which are | basaltic in composition |
| Which of the following is associated with deep mantle hot spots | the volcanoes of Hawaii and Quaternary activity in Yellowstone National Park |
| In general, cinder cones are much larger than shield volcanoes | False |
| Which type of basaltic lava flow has its surface covered with sharp-edged, angular blocks and rubble | aa |
| The most violent volcanic activity is associated with | composite cones |
| The active Hawaiian volcanoes are situated directly above a major boundary between two of the Earth's largest tectonic plates | False |
| ________ is a major dissolved constituent in both magmas and volcanic gases | Water vapor |
| Kilauea is an example of a | shield volcano |
| The recent (geologically) volcanic activity in Yellowstone National Park is | related to intraplate, hot spot volcanism |
| What volcanic events formed Crater Lake, OR? When did they take place | caldera collapse followed major ash and pyroclastic-flow eruptions; 7000 years ago |
| Vents that emit only heated, volcanic gases are called fumaroles | True |
| A ________ volcano is a very large, gently sloping mound composed mainly of basaltic lava flows | shield |
| Ash and lapilli are different sized pyroclastic particles | True |
| Which of the following statements best describes the big Hawaiian volcanoes | are situated in the interior of a large, Pacific plate above a hot spot deep in the mantle |
| Which type of basaltic lava flow has a fairly smooth, unfragmented, ropy surface | pahoehoe |
| Kilauea and Mauna Loa are ________ | basaltic shield volcanoes |
| Magma generation at depth almost always involves partial melting, not complete melting of the source rock | True |
| Small amounts of water can lower partial melting temperatures in silicate rocks | True |
| ____ tend to increase the explosive potential of a magma body beneath a volcano | high viscosity and dissolved gas |
| Paricutin is an example of | a cinder cone |
| ________ destroyed the city of St. Pierre, Martinique in 1902 | A nueƩ ardent |
| Repeated eruptions of relatively fluid lava from fissures can eventually cause an area to be covered by flood basalts | True |
| The ________ is the idea or concept that ancient life forms succeeded each other in a definite, evolutionary pattern and that the contained assemblage of fossils can determine geologic ages of strata | principle of fossil succession |
| Who is credited with formulating the doctrine of uniformitarianism | Hutton |
| Which of the following describes radioactive decay by beta particle emission | the atomic number of the daughter isotope is one more than the parent; the mass numbers are the same |
| After three half-lives, one-ninth of an original, radioactive, parent isotope remains and eight-ninths has decayed into the daughter isotope | False |
| Which of the following is not a very long-lived, radioactive isotope | C-14 |
| When a radioactive isotope decays by electron capture, the electron ________ | combines with a proton in the nucleus; the atomic number of the daughter is one less than the parent |
| What fundamental concept states that in a horizontal sequence of conformable sedimentary strata, each higher bed is younger than the bed below it | law of superposition |
| Sandstone strata and a mass of granite are observed to be in contact. Which of the following statements is correct geologically | the granite is older if the sandstone contains pebbles of the granite |
| The half-life of carbon-14 is about 6000 years. Assume that a sample of charcoal formed by burning of living wood 15,000 years ago. How much of the original carbon-14 would remain today | between one-fourth and one-eighth |
| Which of the following is an essential characteristic of an index fossil | the organism only lived for a short period of geologic time |
| About 88 percent of geologic time is represented by the time span called the | Precambrian |
| Correlation of rock units between continents or widely separated areas is accomplished by using physical features such as color, texture, and thickness of units | False |
| When a beta particle is emitted, the mass number of the isotope remains unchanged | True |
| A worm would stand a poor chance of being fossilized because | worms have no hard parts |
| What is the age of the Earth accepted by most scientists today | 4.5 billion years |
| The percentage of radioactive isotope remaining in a rock sample is 40%. How many half-lives have elapsed since the material was 100% parent atoms? | between l and 2 |
| ________ is an erosional contact between tilted, older strata below and horizontal, younger strata above | An angular unconformity |
| Visualize five, horizontal, sedimentary strata exposed in a cliff or canyon wall identified by consecutive numbers, 1 being the lowest bed and 5 being the highest. Which of the following statements concerning the strata are true | beds l and 3 are older than bed 4 |
| Which of the following geologic observations would not bear directly on working out the sequence of geologic events in an area | the feldspar and quartz contents of a granite |
| Radiometric dating means placing events in their proper sequence | False |
| The geologic time scale was devised before numerical dating using radioactivity was invented | True |
| Assume that you have just examined several flat-lying sedimentary layers. After much study you determine that there is a considerable span of time for which no sedimentary rock layer exists at this site. You have just discovered a(n) | disconformity |
| By applying the law of superposition ________ dates can be determined | relative. |
| What of the following refers to the investigative process by which geologists identify and match sedimentary strata and other rocks of the same ages in different areas | correlation. |
| An unconformity is a buried | surface of erosion separating younger strata above from older strata below. |