Earth's Geologic Processes and Plate Tectonics, Exams of Geology

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Geology Quiz 1 Questions, Earth Science Midterm #1,

Geo 1, Geol1302, Geology Exam 2, Exam 2 PT.2, Geo

Quiz 1, Chapter 04 Plate Techtonics, Geo Chapter 3,

Chapter 13, Chapter 14, Chapter 04 Plate Techtonics,

geol 101: 2.4, geology test 1, oceans test 1

The stream of charged particles given off by the Sun, which prevented the accumulation of hydrogen and helium during the formation of the terrestrial planets, is called - ANS Solar wind With increasing altitude, the concentration of gases in our atmosphere - ANS Becomes less dense By Mass, the four most abundant elements in the Earth are oxygen, silicon, magnesium, and - ANS Iron Of the three primary compositional layers of the Earth (Crust, mantle, core), which is the densest layer - ANS Core The boundary between the crust and the mantle is marked by a seismic-velocity discontinuity called

• ANS The Moho Strong evidence that the Universe is expanding comes from the fact that the light emitted from distant galaxies appears to be - ANS Red-shifted The shape of the Earth's magnetic field is approximately that of a - ANS Dipole Among the choices below, the best estimate of the age of the Universe is - ANS 14 billion years old Unlike the lithosphere, the asthenosphere - ANS Is relatively weak, and flows readily Within the sea floor, the rate of heat flow is greatest - ANS Along mid-ocean ridges At a convergent plate boundary, two opposed plates - ANS Move toward one another

Regions of the sea floor with present day positive magnetic anomalies were formed during times when the Earth's magnetic field - ANS Had normal polarity The age of the oceanic crust ____________ with increasing distance from a mid-ocean ridge - ANS Increases Marine magnetic anomaly belts (on oceanic basaltic crust) run parallel to - ANS Mid-ocean ridges Mid-ocean ridges are - ANS Divergent Earth's geothermal gradient is the rate of temperature change incurred by ____________. - ANS traversing down within Earth's interior Earth's surface is protected from solar wind and cosmic radiation by _________. - ANS Earth's magnetic field Whereas the crust-mantle boundary represents a change in rock type, the lithosphere- asthenosphere boundary is due to a change in the _____________ of the material. - ANS rheology The lithosphere is composed of the ____________. - ANS crust and the uppermost part of the mantle Earth's hydrosphere consists of ____________. - ANS surficial freshwater, the oceans, groundwater, and atmospheric water With increasing altitude, the concentration of gases in our atmosphere ____________. - ANS becomes less dense The rate at which the temperature of the Earth increases with depth is called the _________________ gradient. - ANS geothermal As compared to continental crust, the rocks that make up oceanic crust are ____________. - ANS denser

Rounded to the nearest integer, the average density of the Earth's crust is __________ grams per cubic centimeter. (numeric answer only) - ANS 3 That the Earth is a sphereoid is a relatively new discovery, not widely accepted until the 15th Century when it was confirmed by Columbus's voyage. - ANS False What is the term for gasses contained within liquid rock beneath the surface of the Earth? - ANS volatiles The Earth's mantle is made up mostly of melted peridotite. - ANS false Which rock composes the Earth's mantle? - ANS peridotite The shape of Earth's magnetic field is approximately that of a ________. - ANS dipole (such as that produced by a bar magnet) The thickness of Earth's crust varies from ____________. - ANS 7 to 70 km The Moho ____________. - ANS is found deeper underneath continents than under oceans To the nearest 1000 kilometers, how thick is the Earth's mantle? - ANS Until Columbus's voyage in 1492, most scientists thought the Earth was much smaller than it actually is. - ANS False Continental crust rises higher because it is less _____________ than oceanic crust. - ANS dense Pluton - ANS A blob-like igneous rock body that has cooled beneath the surface of the Earth is called: A sheetlike intrusion that lies parallel to surrounding layers of sedimentary rock. - ANS A sill is:

magma is found beneath the Earth's surface, whereas lava has reached the surface. - ANS The difference between lava and magma is that: A sheetlike intrusion that cuts across preexisting layers - ANS A dike is: All of the above: Are formed through the freezing of melt Can be produced at the surface of the Earth as well as deep below the surface Are the most common types of rocks within Earth - ANS Igneous rocks True - ANS Very early in Earth's history, it was so hot that the surface was likely entirely molten Intrusive Igneous Rocks - ANS When magma crystallizes,__________ are formed. Have a tendency to evaporate and are stable as gases - ANS Volatiles refer to substances that Decrease - ANS If the volatile content of magma is increased, its viscosity will: Increase - ANS If a body of magma becomes more felsic, its viscosity will: Cool and solidify more quickly - ANS As compared to coarse- grained igneous rocks, all fine grained igneous rocks: Cool more slowly - ANS All other factors being equal, intrusive rocks that form deep within Earth_________ than intrusive rocks that cool near the surface. All of the above: is volcanic glass possesses conchoidal fracture typically is felsic in composition - ANS Obsidian are lighter in color than mafic rocks. - ANS Most commonly, felsic igneous rocks:

water and carbon dioxide - ANS Important volatiles in magmas include felsic - ANS Which type of magma has the greatest silica content? False - ANS When rock is melted within Earth, typically the entire volume of rock is transformed from a solid state to a liquid. Streak - ANS The color of a mineral in powdered form is termed: Chemistry, specifically the anions within the chemical formula. - ANS Minerals are classified into groups primarily on the basis of: False - ANS Topaz, with Mohs hardness of 8, is twice as hard as fluorite, with Mohs hardness of 4. Earth orbits around the Sun - ANS In the heliocentric model 14 billion - ANS Among the choices below, the best estimate of the age of the Universe is__________years old. All matter in the Universe was once confined to a single point. - ANS The big bang theory states that red-shifted - ANS Strong evidence that the Universe is expanding comes from the fact that the light emitted from distant galaxies appears to be Mars, Mercury, and Venus - ANS Aside from Earth, the terrestrial planets are Jupiter, Saturn, Uranus, and Neptune - ANS The gas-giant, or Jovian, planets are cosmology - ANS The branch of science that studies the structure and history of the Universe is the Sun - ANS All objects in the Solar System are in orbit around

the Milky Way - ANS Our Sun belongs to a galaxy known as expanding - ANS In agreement with the Big Bang theory, our Universe is solar wind - ANS The stream of charged particles given off by the Sun is called very hot - ANS Differentiation of the core from the mantle early in Earth's history was possible because the planet was________at the time denser - ANS The metal alloy that makes up the core of the Earth is_______________ as compared to the rocky mantle dipole (such as that produced by a bar magnet) - ANS The shape of Earth's magnetic field is approximately that of a iron - ANS In the whole Earth, the four most common elements are oxygen, silicon, magnesium, and crust and the uppermost part of the mantle - ANS The lithosphere is composed of the and pressure both increase - ANS Moving into the interior of Earth, temperature 7 to 70 km - ANS The thickness of Earth's crust varies from core - ANS Of the three primary chemical layers of the Earth (crust, mantle, core), which is the thickest layer? core - ANS Which of Earth's layers has the greatest density? becomes less dense - ANS With increasing altitude, the concentration of gasses in our atmosphere denser - ANS As compared to continental crust, the rocks that make up oceanic crust are

asthenosphere - ANS The lithosphere lies directly above the cooler and less able to flow - ANS As compared to the asthenosphere, the lithosphere is combined to form a supercontinent (he termed Pangaea) - ANS Based on evidence from fossils, glacial deposits, and the fit of the continents, Wegener proposed continental drift that suggested all of the continents were once he could not conceive of a valid mechanism that would cause continents to shift positions - ANS Wegner's idea of continental drift was rejected by American geologists because agree that continental drift occurs; the mechanisms that drive drift are at work in the ocean basins and upper mantle and were unknown in Wegener's time - ANS Currently, most geologists False - ANS The apparent polar-wander paths for continents indicate actual position of the paleopole. along mid-ocean ridges - ANS Sea-floor spreading is driven by volcanic activity had normal polarity - ANS Regions of the sea floor with positive magnetic anomalies were formed during times when Earth's magnetic field had reversed polarity - ANS Regions of the sea floor with negative magnetic anomalies were formed during times when Earth's magnetic field sea-floor spreading rates are relatively rapid - ANS Marine magnetic anomaly belts are widest when and where increases - ANS The age of oceanic crust ________ with increasing distance from a mid-ocean ridge. False - ANS Wegener's evidence for a united Pangaea was so compelling that virtually all geologists agreed with the idea of continental drift during his lifetime.

Africa - ANS Distinctive rock sequences on South America terminate at the Atlantic Ocean but reappear on the continent of drifting of the North American continent - ANS The apparent polar-wander path obtained from magnetite crystals in basalts on the North American continent is now interpreted to be the result of False - ANS The deep ocean floor is flat and nearly featureless incorporates and explains both sea-floor spreading and continental drift - ANS The theory of plate tectonics is relatively weak and flows readily - ANS Unlike the lithosphere, the asthenosphere is thicker than oceanic lithosphere - ANS Continental lithosphere 150 km - ANS The average thickness of continental lithosphere is about least near the mid-ocean ridges and thickens away from the ridges - ANS The thickness of oceanic lithosphere is discrete layers of lithosphere that are vertically stacked one atop the other - ANS Under the theory of plate tectonics, the plates themselves are a continental coastline that coincides with a plate boundary - ANS In the terminology of plate tectonics, an active margin is passive margins - ANS Continental coastlines that occur within the interior of a tectonic plate are called oceanic or continental lithosphere or a combination of both - ANS Tectonic plates might consist of primarily on the margins of tectonic plates - ANS Deformed (bent, stretched, or cracked) lithosphere occurs

the presence of an earthquake belt - ANS Every plate boundary can be recognized by 1 to 15 cm/year - ANS Tectonic plates move at rates that are approximately move away from one another - ANS At a divergent plate boundary, two opposed plates move toward one another - ANS At a convergent plate boundary, two opposed plates slide past one another - ANS At a transform plate boundary, two opposed plates False - ANS All lithospheric plates are approximately the same size and contain a combination of oceanic and continental crust along mid-ocean ridges - ANS The youngest sea floor occurs the addition of new lithosphere mantle as a result of cooling - ANS Oceanic lithosphere thickens away from the mid-ocean ridge primarily due to convergent plate boundaries - ANS Subduction zones are may be composed or either oceanic or continental lithosphere. - ANS At a subduction zone, the overriding plate earthquakes are common, but volcanoes are absent - ANS At transform plate boundaries the boundaries of three lithospheric plates meet at a single point - ANS A triple junction is a place on Earth's surface where transform faults - ANS Segments of the mid-ocean ridge system are offset. Between the offset segments we observe collision and mountain formation - ANS When two bodies of continental lithosphere are pushed together at a convergent boundary, the result is

coal, which was formed from ancient tropical plants - ANS Which of the following is a mineral? True - ANS Two distinct minerals may have the same chemical formula False - ANS A single mineral may take on multiple crystalline lattice structures. does not have fixed crystalline structure - ANS Natural glass is not considered a mineral because it the crystals have abundant room to grow in their hollow surroundings - ANS Minerals in geodes form spectacular euhedral crystals because False - ANS Diamond and graphite are both polymorphs of pure silicon. False - ANS The most useful diagnostic property of minerals is their color in hand sample less variable than the color hand sample among crystals - ANS For the majority of minerals, the streak color obtained when the mineral is scratched against a porcelain plate is luster - ANS The shininess of a mineral is a helpful diagnostic property termed a tendency to break along planes of weakness - ANS Cleavage in minerals refers to silicates - ANS The most abundant minerals belong to a chemical group termed the calcite - ANS When in contact with hydrochloric acid, which mineral gives off bubbles of carbon dioxide gas? oxygen - ANS The silica tetrahedron that forms the backbone of all the silicate minerals is composed of silicon and what other element False - ANS All minerals are chemical compounds (composed of more than one element)

an ability to resist being scratched by other substances - ANS With regard to minerals, hardness refers to petroleum - ANS Which of the following is NOT a mineral? none of the above; multiple properties must be used to diagnose a mineral - ANS The single property that can be used to identify any mineral is What are the periods of the Mesozoic? - ANS Triassic, Jurassic, and Cretaceous When did the Mesozoic start and end? - ANS 251 mya-66 mya During the Triassic Period, what was happening to Pangaea - ANS Breakup: Rifting between Laurasia and Gondwana When Laurasia and Gondwana separated during the Triassic period, what happened in terms of modern day continents? - ANS Separation of North America from Africa, then rifting of North America and South America When did Pangaea form? - ANS During the Paleozoic What happened during the late Triassic and Jurassic to Pangaea? - ANS Gondwana starting breaking apart In terms of modern continents, what happened to Pangaea during the Late Triassic and Jurassic? - ANS Antarctica and Australia began separating from South America and Africa, India began rifting from the Gondwana continent When does the North American continent emerge/when can we call it the North American continent? - ANS During the late Triassic and Jurassic What happened to Pangaea in terms of modern continents in the Late Jurassic? - ANS South America and Africa began separating

What happened in regards to Pangaea at the End of the Cretaceous? - ANS Australia and Antarctica had separated, India was nearly at the equator, South America and Africa were widely separated, and Greenland was an independent landmass What was a characteristic of the breakup of Pangea during the Cretaceous period? - ANS Globally high sea level due to increased rifting and heat flow What was happening on the East Coast of North America in the Mesozoic? - ANS Weathering of the Appalachians, sediment- filled fault block basins as result of rifting, lava flows and intrusion of sills What is an example of what was happening to the East Coast of North America in the Mesozoic? - ANS Palisades in New York What was happening the Gulf Area of North America during the Mesozoic? - ANS >1000m of evaporate precipitated, source of Paleogene salt domes, part of cretaceous interior seaway in cretaceous What were the bivalves found in reefs in the Gulf of Mexico during the Cretaceous Period called? - ANS Rudists When was the Gulf of Mexico formed? - ANS Formed as North America separated from South America during the Late Triassic and Early Jurassic What was happening to the Gulf of Mexico during the Late Jurassic period? - ANS circulation in the Gulf was less restricted and Evaporite deposition ended What is the Atlantic Ocean margin? - ANS Passive Continental Margin, rifting ceased, active plate margin became a passive, trailing continental margin, sediments contributed to the growing eastern continental shelf What was happening to the Western Region of North America during the Jurassic Period of the Mesozoic? - ANS Sonoma Orogeny and thrusting What was happening to the Western Region of North America during the Late Jurassic Period of the Mesozoic? - ANS Westward movement of North America over the Farallon Plate, subduction zone,

leading to Cordilleran Orogeny; related emplacement of batholiths, Keystone Thrust Fault in Nevada, accretion of terranes What is the Sonoma Orogeny? - ANS Thrusting of oceanic and island arc rocks eastward against the craton margin After the Sonoma Orogeny, what did the western margin of North America become? - ANS An Oceanic-Continental Convergent Plate Boundary What is the Cordilleran Orogeny? - ANS Mountain building activity that began during the Jurassic and Continued into the Cenozoic, series of individually named, but interrelated, mountain-building events What were the three phases of the Cordilleran Orogeny starting from oldest to youngest? - ANS Nevadan, Sevier, and Laramide What happened in the Nevadan Orogeny and when did it occur? - ANS Jurassic/Cretaceous Period Eastward subduction of oceanic crust, formation of huge batholiths that are known as Sierra Nevada, Southern California, Idaho, and Coast Range batholiths What is a batholith? - ANS A very large igneous intrustion extending deep in the earth's crust What was the Sevier Orogeny? - ANS The second phase of the Cordilleran Orogeny, thrusting that occurred progressively farther east What is an example of a thrust fault that happened in the Sevier Orogeny? - ANS Keystone Thrust Fault What is the Laramide Orogeny and when did it occur? - ANS Final phase of the Cordilleran Orogeny in the Late Cretaceous to Early Cenozoic Where did most of the features of the present-day Rocky Mountains result from? - ANS Cenozoic phase of the Laramide Orogeny

What is a terrane? - ANS A fragment of crustal material formed on, or broken of from, one tectonic plate and accreted or "sutured" to crust lying on another plate What happened in regards to Mesozoic sediments in the West? - ANS Regressing shallow sea in the Triassic period, led to deposition of limestones, evaporates, dune, and Morrison Formation What is an example of a dune formed during the Triassic and Jurassic periods? - ANS Navajo Sandstone in Zion National Park What is significant about the Morrison Formation? - ANS It's the world's richest Jurassic dinosaur fossil assemblage What is significant about the Navajo Sandstone? - ANS thickest and most prominent of the Jurassic cross-bedded sandstones What type of environment is the Navajo Sandstone in? - ANS Coastal Dune Environment What is the Sundance Sea? - ANS Mid-Continental Sea in North America, flooded twice in the interior of western North America What happened to the Sundance Sea during the Late Jurassic? - ANS Retreated northward during the Nevadan Orogeny What are cycads? - ANS Preserved logs of gymnosperms, especially conifers and plants The mountain building events of the west coast that began in the Jurassic and continued into the Cenozoic are collectively called the _______________ Orogeny - ANS Cordilleran When did Mid-Cretaceous Transgressions occur? - ANS Beginning of the Late Cretaceous What are Mid-Cretaceous Transgressions? - ANS Incursion from the Gulf area, joining the Arctic waters to create an enormous Cretaceous Interior Seaway

What were the Cretaceous Facies related to the Servier Orogeny? - ANS Facies of the Western Cretaceous Interior Seaway shows the facies relationship to the Sevier orogenic belt What happened to the terranes of western North America? - ANS Terranes were carried great distances What are examples of terranes? - ANS Island Arcs, Seamounts, Oceanic Ridges What percent of the Pacific Coast from Alaska to Baja California consisted of accreted terranes? - ANS More than 25% Cretaceous Marine Transgressions onto the continents were caused by: A. High Sea Level due to Warm Climate B. Inflated Oceanic Crust due to Fast Seafloor Spreading C. Uplift of landmasses D. A and B - ANS A and B Magma, Petroleum, and Cubic Zirconia are minerals - ANS False Natural glass is not considered a mineral, because it? - ANS does not have a fixed crystalline structure A single mineral can take on many different internal structures (i.e. internal atomic arrangements) and still be considered the same mineral - ANS False The nucleus of most atoms? - ANS contains protons and neutrons ________ bonding occurs when atoms share electrons - ANS covalent Minerals are classified into different mineral classes primarily on the basis of? - ANS chemistry, specifically the anions within the chemical formula Silicates are the most abundant mineral class on Earth - ANS True

The silica tetrahedron that forms the backbone of all silicate minerals is composed of silicon and what other element? - ANS oxygen Felsic minerals are? - ANS all silicate minerals rich in silicon and often rich in aluminum Quartz is a mafic mineral - ANS False The single property that can be used to identify any mineral is? A. Cleavage B. Color C. Luster D. None of the above - ANS D. None of the above Trace amounts of an impurity in a mineral can commonly produce significant differences in __________ among individual crystals of the same mineral. A. color B. specific gravity C. luster D. streak - ANS A. color For the majority of minerals, the streak color obtained when a mineral is scratched against an unglazed porcelain plate (i.e. a streak plate) is? - ANS less variable than the color in hand samples among crystals of the same mineral ________describes the manner in which a mineral surface reflects light A. fracture B. hardness C. luster D. streak - ANS C. luster Cleavage in minerals refers to? - ANS a tendency to break along planes of weakness

The hardness of a mineral refers to its resistance to being broken. - ANS False The most recently formed portion of any crystals is always found deep within the interior. - ANS False Minerals that do not posses cleavage are said to possess___ A. invulnerability B. fracture C. massiveness D. solidity - ANS B. fracture Quartz is a mineral that exhibits a conchoidal fracture - ANS True ______is a mineral property defined by the density of the mineral sample divided by the density of water (1 gram/cubic centimeter). A. specific gravity B. streak C. magnetism D. color - ANS A. specific gravity ________ lava flows have the highest viscosity. A. Andesitic B. Basaltic C. Rhyolitic - ANS B. Rhyolitic A'a' lava flows typically form further from the vent than pahoehoe lava flows. - ANS True The basalt erupting at the top of a MOR forms? A. a'a' B. columnar joints C. lava tubes

D. pillow lavas - ANS D. pillow lavas Pyroclastic fragments that are less than 2 millimeters (mm) are called? A. ash B. blocks C. bombs D. cinders - ANS A. ash Fissure Eruption - ANS Pyroclastic Flow - ANS Pahoehoe Lava Flow - ANS Pyroclastic Fall - ANS Flood Basalts - ANS Plutonic = - ANS intrusive Volcanic = - ANS extrusive Intrusive igneous rocks - ANS phaneritic texture Extrusive igneous rocks - ANS aphanitic texture Extrusive igneous rocks - ANS vesicular and glassy textures How is magma formed? - ANS partial melting in the mid-to-lower crust and upper mantle location of a Hot spot? - ANS base of lithosphere

where is a hot spot? - ANS top of a mantle plume, where temperatures can cause melting

1. Ways to decrease pressure? - ANS decompression melting
2. Ways to decrease pressure? - ANS mid-ocean ridges
3. Ways to decrease pressure? - ANS continental rifts
4. Ways to decrease pressure? - ANS mantle plumes Basaltic flow is Mafic. - ANS True Rhyolitic "flow" isn't silicic? - ANS False Pahoehoe is? - ANS ropy A'A' is? - ANS blocky Lava Tubes - ANS The empty space left when a lava tunnel drains Pillow Lava - ANS glass encrusted basalt blobs that form when magma extrudes on the seafloor and cools very quickly Rhyolitic flow - ANS Size of ash? - ANS < 2mm Size of lapillior or cinders? - ANS 2-64 mm Size of blocks or bombs? - ANS >-64 mm

Pyroclastic flow is a? - ANS superheated, quick flow of gas and rock Pyroclastic flows? - ANS go downhill or spread downhill laterally under gravity Pyroclastic falls? - ANS ejected fragments that fall through the air Are Pyroclastic flow silicic? - ANS Yes Types of eruptions? - ANS Effusive and explosive Types of Volcanos? - ANS Shield Composite Cone lava dome Sea-floor spreading is driven by volcanic activity ____________. - ANS along mid-ocean ridges The age of oceanic crust ____________ with increasing distance from a mid-ocean ridge. - ANS increases Continental lithosphere ____________. - ANS is thicker than oceanic lithosphere The thickness of oceanic lithosphere is ____________. - ANS least near the mid-ocean ridges and thickens away from the ridges Every plate boundary can be recognized by ____________. - ANS the presence of an earthquake belt At a convergent plate boundary, two opposed plates ____________. - ANS move toward one another Mid-ocean ridges are ____________. - ANS divergent plate boundaries

At a subduction zone, the downgoing (subducting) plate ____________. - ANS is always composed of oceanic lithosphere At transform plate boundaries ____________. - ANS earthquakes are common, but volcanoes are absent Hawaii is an example of ____________. - ANS hot-spot volcanism The smoky cloud that rises from the vent of an actively erupting volcano is composed of ____________. - ANS fine volcaniclastic debris (ash) suspended in the air Basaltic lavas that solidify at the surface before flow ceases fracture irregularly, producing a sharp- surfaced lava rock named ____________. - ANS a'a' Pillow lavas are associated with ____________. - ANS submarine basaltic eruptions Ash, cinders, and blocks are all types of ____________. - ANS volcaniclastic debris Explosive or voluminous eruptions may cause the volcano to collapse on the floor of the (now empty) - ANS caldera Whether an eruption will primarily produce lava flows or pyroclastic debris is influenced by ____________. - ANS the proportion of volatiles within the lava the viscosity of the lava the composition of the lava all answers are possible The Hawaiian island chain is an example of a(n) ____________. - ANS hot-spot island chain Of the three primary forms of subaerial volcanoes, ____________ have the most gently sloping sides, due to - ANS shield volcanoes

Of the three primary forms of subaerial volcanoes, ____________ consist of a simple, conical pile of tephra. - ANS cinder cones Of the three primary forms of subaerial volcanoes, ____________ consist of alternating layers of tephra and - ANS stratovolcanoes terrestrial planets are mainly composed of - ANS rock and metals Jovian planets are composed of - ANS volatiles in the heliocentric model - ANS earth orbits around the sun Eratosthenes was the first person to accurately estimate the size of Earth. He accomplished this feat by - ANS observing shadows simultaneously cast at two different cities that were separated by a known distance Humans first realized that the Earth was spherical - ANS during the time of Aristotle in ancient Greece The geocentric model was developed during the time of the ancient Greeks. This model - ANS was held to be true by thinkers throughout the Middle Ages, up until the Renaissance Over 2,000 years ago, an ancient Greek astronomer concluded (correctly) that the - ANS Earth orbits the Sun in a circular orbit An important contribution made by Copernicus is his (correct) assertion that the - ANS Sun is the center of the Earth's orbit In ancient Greece, Eratosthenes measured the difference in angles of the Sun's rays in two different locations in Egypt at the same time to calculate the - ANS circumference of the Earth Aside from Earth, the terrestrial planets are - ANS Mars, Mercury, and Venus Our Sun belongs to a galaxy known as - ANS Milky Way

The circumference of Earth is most nearly - ANS 40,000 km Because of the Doppler effect, a light- or sound-emitting object moving toward you has a ________ compared to a stationary object. - ANS higher frequency The change in wavelength (and, therefore, frequency) of waves that happens if the source of the waves is moving is explained by the ________. - ANS Doppler effect According to the Big Bang theory, our Universe is ________. - ANS expanding By far the most common elements in the Universe and in our Solar System are ________. - ANS hydrogen and helium Volatile materials can exist as a gas at Earth's surface. Which of the following is NOT a volatile material? - ANS silicon Differentiation of the core from the mantle early in Earth's history was possible because the planet was ________ at the time. - ANS very hot The metal alloy that makes up the core of Earth is ________, as compared to the rocky mantle. - ANS denser Scientists believe that the Moon formed due to a large planetesimal colliding with the Earth because it has a composition similar to ________. - ANS Earth's mantle If one were to see a comet passing by Earth, it is likely that this comet originated from ________. - ANS the Kuiper belt the shape of earths magnetic field is approximately that of a - ANS dipole, such as that produced by a bar magnet Presently, Earth's atmosphere is dominated by which two gases? - ANS nitrogen and oxygen

If one were to ride a hot air balloon up into the atmosphere, one would experience the concentration of gases ________. - ANS becoming less dense Earth's surface is protected from solar wind and cosmic radiation by ________. - ANS Earth's magnetic field Substances that can be transformed to a gas at relatively low temperatures are termed ________. - ANS volatiles The most common minerals within Earth are ________. - ANS silicates Hot, liquid rock beneath Earth's surface is termed ________. - ANS magma Earth's geothermal gradient is the rate of temperature change incurred by ________. - ANS traversing down within Earth's interior During a journey to the center of the Earth, one would experience temperature ________. - ANS and pressure both increasing The densest layer of Earth is the ________. - ANS inner core Compared to oceanic crust, continental crust is ________. - ANS thicker As compared to the rocks that make up the crust, Earth as a whole is ____________. - ANS considerably more dense The boundary between the crust and the mantle is marked by an abrupt change in seismic velocity called the ________. - ANS Moho The lithosphere lies directly above the ________. - ANS asthenosphere As compared to the asthenosphere, the lithosphere is ________. - ANS cooler and less able to flow

What does an ordinary compass indicate? - ANS magnetic north Hot-spot tracks result from moving _____________. a. plates b. asthenosphere c. mantle plumes d. hot spots - ANS a. plates The theory of plate tectonics ____________. a. incorporates continental drift but not sea-floor spreading b. incorporates sea-floor spreading but not continental drift c. incorporates and explains both sea-floor spreading and continental drift d. does not incorporate sea-floor spreading or continental drift - ANS c. incorporates and explains both sea-floor spreading and continental drift Oceanic lithosphere thickens away from the mid-ocean ridge primarily due to ____________. a. the addition of new crust due to sedimentation b. the addition of new crust due to hot-spot volcanism c. reasons that geologists cannot determine at present d. the addition of new lithospheric mantle as a result of cooling - ANS d. the addition of new lithospheric mantle as a result of cooling The thickness of oceanic lithosphere is ____________. a. greatest near the mid-ocean ridges and thins out away from the ridges b. uniformly 100 km c. greatest at the geographic poles and least near the equator d. least near the mid-ocean ridges and thickens away from the ridges - ANS d. least near the mid- ocean ridges and thickens away from the ridges The primary difference between lithospheric and asthenospheric mantle that gives rise to numerous divergent patterns of physical behavior, is ____________. a. temperature (the lithosphere is cooler than the asthenosphere)