Geology HW questions

The earths atmosphere is mostly comprised of which two gases? a. oxygen b. co2 c. argon d. methane e. ozone f. nitrogen

oxygen and nitrogen

Which of the following is NOT a type of pyroclastic debris? a. bombs b. ash c. pahoehoe d. block e. lapilli

pahoehoe

Of the following plate tectonic settings, where are igneous rocks NOT typically created? a. hot spots b. passive continental margins c. mid-ocean ridges d. continental rifts e. convergent plate boundaries

passive continental margins

Why do the minerals in geodes form euhedral crystals rather than anhedral grains? a. all of the elements incorporated in the crystals are in plentiful supply b. minerals within geodes always contain iron c. minerals within geodes are always framework silicates d. the crystals have abundant room to grow in their hollow surroundings

the crystals have abundant room to grow in their hollow surroundings (new crystals grow outward from the central seed. as time passes they maintain their shape until they interfere with each other. a crystal growing in a confined space will be anhedral)

What factors control the cooling time of magma within the crust? a. the depth at which the magma cools b. the volume of the intruded magma c. the heat difference between the magma and the surface d. the rate at which heat is absorbed from the surroundings e. surface water passing over the magma

the depth at which the magma cools, the volume of the intruded magma

Large volcanoes consisting of interbedded layers of ash and lava are called: a. cinder cones b. shield volcanoes c. calderas d. stratovolcanoes e. scoria cones

stratovolcanoes

Earths tectonic plates move at rates of about

1 to 15 cm a year

The age of a magnetic anomaly stripe of a rock that is 200 km away from the mid ocean ridge axis is 10 million years. What is the rate of sea-floor spreading at this ridge, assuming the rate is constant? a. 50 km/yr b. 2 cm/yr c. 2 km/yr d. 10 m/yr e. 5 m/yr

2 cm/yr

On the hypsometric curve, most of the ocean bottom lies at what depth? a. 2-4 km below sea level b. 0-5 km below sea level c. 6-10 km below sea level d. 4-6 km below sea level e. about 5 km below sea level

4-6 km below sea level

What is the proportion of land and water on earth?

70% ocean 30% land

What is the force that holds the sun, planets, moon and other smaller objects in the solar system in place? a. nuclear fission b. black holes c. gravity d. the big bang e. Doppler effect

gravity

Which of the following properties are useful in mineral identification? a. texture b. hardness c. crystal habit d. cleavage and fracture e. hardness, crystal habit, and cleavage and fracture

hardness, crystal habit, and cleavage and fracture

Which factors cause melting and thus the formation of magma? Select all that apply a. heat transfer b. rapid cooling c. crystallization d. volatiles e. compression f. decompression

heat transfer, volatiles, decompression

atoms that are heavier than iron are generally produced by: a. high energy fusion reactions during the explosion of supernovas b. the big bang c. fission reactions within a star d. normal fusion reactions during the lifetime of the star

high energy fusion reactions during the explosion of supernovas

Stationary thermal plumes burning through a plate Can be found in the interiors of plates, away from the boundaries but a few grew on mid ocean ridges They create continental crust Found above them are volcanoes

hot spots

Different versions of an element have the same atomic number but a different atomic weight Number of neutrons may change Carbon has 6 protons and 6 neutrons but if it has 7 neutrons it is an _____

isotope

How did geologists learn about the layered structure of earths deep interior? a. drilling deep well and sampling rocks b. sending space probes to sample other planets in our solar system c. measuring rates of plate tectonic movements d. studying earthquake (seismic) waves

studying earthquake (seismic) waves

Which characteristic is NOT useful in the classification of igneous rocks: a. texture b. density c. mineral constituents d. grain size e. all are useful

all are useful

The rate at which temperature increases as depth increases is the: a. concentration gradient b. metamorphic grade c. geothermal gradient d. Milankovitch cycle

geothermal gradient

How did 1920's astronomer Edwin Hubble Explain his observations that all light from distant galaxies exhibits the red-shift Doppler effect?

All galaxies are moving apart, therefore the Universe is expanding

Astrophysicists conclude the big bang was responsible for: a. The origin of the universe b. The formation of initial hydrogen and helium atoms c. All answers are correct d. none of the answers are correct

All of the possible answers are correct

Commercial definition for minerals that are flexible, chemically and thermally resistant and can be woven

Asbestos

What is the difference in viscosity and the corresponding lava flow of andesitic, basaltic and felsic flows?

Basaltic lava can flow long distances due to its low viscosity. An andesitic flow is more viscous and it tends to break up as it flows. Felsic lava is so viscous that it may accumulate to form a lava dome.

Which of the following is a way in which minerals can form? a. freezing/solidifying from a melt b. precipitation from a liquid solution c. through biological processes (a clam shell) d. precipitation from a gas e. all of the above

all of the above

Type of asbestos that has never been shown to cause any lung related diseases Only type of asbestos currently mined Most commonly used asbestos in north america

Chrysoltile

Which boundary do the following most often occur at? subduction zones deep sea trenches flux melting

Convergent

SHARING of electrons Form when shells are about half full STRONG bond

Covalent bonding

Type of asbestos that forms sharp needle like fibers that can puncture lungs

Crocidolite

The growth of a solid from a gas or liquid whose constituents come together in the proper chemical proportions and crystalline arrangement (ex ICE)

Crystallization

What are the 3 polymorphs of carbon

Diamond, Graphite, Buckminster Fullerene

Where do diamonds come from? Are they brought up fast or slow?

Diamonds are formed in the mantle and they are brought up from the mantle to the surface quickly through KIMBERLITE PIPES

Which boundary do the following most often occur at? sea floor spreading rifts decompression melting

Divergent

What makes earth unique in our solar system?

Earth has liquid water

solid naturally occurring homogenous (same kind; alike) Inorganic compound (NO organic carbon) Crystalline solid Specific chemical compound

Mineral

Two different minerals (diamond and graphite) that have the same composition but different crystal structures

Mineral Polymorphs

Basaltic lava is more viscous than rhyolitic lava and therefore can flow easily over long distances a. True b. False

False

The most abundant rock type in the earths crust

Igneous rocks

Which of the following is useful in predicting an impending volcanic eruption? a. earthquake activity b. crustal heat flow c. shape of the volcano d. quantity and composition of gas emissions e. All of the above

all of the above

TRANSFER of electrons form when shells are nearly empty or nearly full WEAK bond

Ionic bonding

Imagine you hear a character in a low budget science fiction movie say he will "return ten light years from now". What, if anything is wrong with his usage of the term?

Light years are a measure of distance

Which of the following is NOT relevant to the nebular theory of planetary formation? a. explains origin of planets, moons, asteroids, comets b. explains differences between terrestrial and jovian planets c. dust and ice particles from a nebula cloud collide to form planetesimals d. planetesimals consume material in their paths, growing into spherical planets e. magnetic fields form in planets from the presence of iron minerals

Magnetic fields form in planets from the presence of iron minerals

Although important in subduction, is not the dominate driving force. This horizontal force is caused by the change in height from the ridge to the trench located at the subduction zone. The mathematical expression can be derived using the concept of gravitational energy. Taking into account decompression melting happening in the mid-oceanic ridge, altering the density of melt throughout the column, change in temperature between the average lithospheric mantle and asthenosphere and convection, one can determine the _____ _____ ______

Ridge Push Force

The dominating driving force in subduction, driving the entire process. This process is density driven, dominated by the density contrast between the lithosphere and mantle. The larger the gradient in density, the greater the pull force on the downgoing slab. This driving force is essential to volcanic arc building because it is this process that is dominating subduction which in turn is setting up the correct conditions for partial melting, which then induces new crust to form "Pull by cold crust as it sinks into the mantle at a convergent boundary as the subducting slab descends it induces mantle sicurlation"

Slab Pull Force

Occurs when a subducting slab drives flow in the nearby mantle. This flow then exerts shear tractions on nearby plates. This driving force is important when the slabs (or portions thereof) are not strongly attached to the rest of their respective tectonic plate. They cause both the subducting and overriding plate to move in the direction of the subduction zone. "Pulling the plate towards the trench"

Slab Suction Force

An oceanic transform fault is the actively sliding part of a fracture zone on the sea floor. It links segments of a mid-ocean ridge. Which of the following is correct a. both the transform fault and the overall fracture zone increase in length over time at the same rate b. the fracture zone increases in length over time while the transform fault decreases in length over time c. the length of the fracture zone increases as sea-floor spreading takes place, whereas the length of a transform fault stays the same d. both the transform fault and the overall fracture zone decrease in length over time at the same rate

The length of the fracture zone increases as sea-floor spreading takes place, whereas the length of a transform fault stays the same

Wegeners proposal that continents move ("drift) relative to one another took decades to be accepted by geologists worldwide because? a. most of his observations were wrong b. geologists found rocks along coasts of continents on opposite sides of the Atlantic did not match c. Wegener could not provide a mechanism explaining how continents could drift

Wegener could not provide a mechanism explaining how continents could drift

Which of the following locations is characterized by continental hot spot volcanism? a. Hawaii b. Yellow Stone National Park Region c. Columbia Plateau, Northwestern United States d. Iceland e. Mt. Fuji Japan

Yellowstone National Park Region

A dike is ____: a. a sheetlike intrusion that lies parallel to surrounding layers of sedimentary rock b. a cooled layer of lava c. an intrusion formed within the magma chamber of a volcano d. a sheetlike intrusion that cuts across preexisting layers

a sheetlike intrusion that cuts across preexisting layers

A body of deformed sediments, wedge shaped in two dimensions or prism shaped in three dimensions, that has been scraped off the surface of the oceanic lithosphere as it moves downwards beneath a continent or island arc. The sediments are added to the continental edge

accretionary prism

Igneous rocks can be: a. intrusive b. extrusive c. volcanic ash d. pyroclastic flow e. all answers are correct

all answers are correct

Viscosity of lava is dependent on: a. silica content b. temperature c. gas content d. chemical composition e. all answers are correct

all answers are correct

Which distinguishes continental and oceanic lithosphere? a. density b. composition c. thickness d. age e. all are correct

all are correct

Effusive eruptions are characterized by ___, while explosive eruptions have ___ a. lava flows; pyroclastic debris b. low viscosity lava; high viscosity lava c. low gas content; high gas content d. hotter magma; cooler magma e. all of the above are correct

all of the above are correct

Sea-floor spreading is driven by volcanic activity: a. in the middle of abyssal plains b. along mid-ocean ridges c. at the edges of continental shelves d. along fracture zones

along mid-ocean ridges

The hardness of a mineral is determined by: a. an absence of cleavage b. an ability to resist being scratched by other substances c. an ability to resist breaking when being struck with a hammer

an ability to resist being scratched by other substances

Igneous rocks are formed from magma that originates in the: a. upper crust b. asthenosphere c. outer core d. inner core e. all of the above

asthenosphere

Flood basalts form: a. when a pyroclastic flow mixes with a nearby water source b. at continental rifts, where vast bodies of lava flow from fissures c. from the sudden release of accumulated gas pressure within a volcano d. when the overriding plate at the subduction zone is composed of oceanic lithosphere

at continental rifts, where vast bodies of lava flow from fissures

Lava is found ___ while magma occurs ___ a. at earths surface; beneath the surface b. in a volcano; in a fissure c. at great depths; as a surface eruption d. on continents; in a mid-ocean ridge e. after it solidifies; in a liquid state

at earths surface; beneath the surface

Which of the following does NOT affect magma or lava viscosity? a. temperature b. buoyancy c. volatile content d. amount of silica e. presence of water

buoyancy

Atoms combine (bond) by losing, gaining or sharing electrons to form minerals

chemical bonding

What is the prime characteristic that geologists use to separate minerals into classes? a. chemical composition, specifically the anions within the chemical formula b. chemical composition, specifically the cations within the chemical formula c. hardness; hard, soft, and medium are the three primary classes d. number of cleavage directions present

chemical composition, specifically the anions within the chemical formula

Wegener proposed the idea of continental drift after he observed evidence from fossils, glacial deposits, and the fit of the continents that suggested all the continents were once: a. aligned east to west along the equator during the late mesozooic through the cenozoic b. combined to form a supercontinent (Pangea) in the late Paleozoic through the Mesozoic c. Aligned north to south along the prime meridian during the late Cenozoic d. combined to form a supercontinent (rodinia) in the Proterozoic

combined to form a supercontinent (Pangea) in the late Paleozoic through the Mesozoic

What is NOT true about earths crust? a. composition of oceanic crust is felsic (granite like) and the composition of the continental crust is more mafic (basalt rocks) b. continental crust is 4-5 times thicker than oceanic crust c. oxygen is most abundant element in earth's crust d. continental crust has lower density than oceanic crust

composition of oceanic crust is felsic (granite like) and the composition of the continental crust is more mafic (basalt rocks)

Which of the following is not considered a mineral? a. quartz b. diamond c. concrete d. salt e. gold

concrete

Rhyolitic and andesitic lavas are most common in which volcanic setting? a. mid ocean ridges b. continental arcs c. oceanic hot spots d. island arcs e. all answers are correct

continental arcs

Polar wandering is a misleading term because: a. only magnetic declination changes through time b. earths magnetic field is constantly changing, making it impossible to reconstruct past pole positions c. continents wander relative to poles; the average pole position through time is stable d. only magnetic inclination changes through time e. magnetic polarity recorded in ancient rocks is constantly changing and thus is not measurable

continents wander relative to poles; the average pole position through time is stable

What type of plate boundaries do volcanoes occur at? a. convergent b. divergent c. transform

convergent

As compared to coarse-grained igneous rocks, all fine-grained igneous rocks: a. cool and solidify more quickly b. solidify at higher temperatures c. cool and solidify more slowly d. solidify at lower temperatures

cool and solidify more quickly

Earth is a planet made up of the following three layers of increasing density: a. crust, mantle, core b. atmosphere, hydrosphere, lithosphere c. granite, basalt, gabbro d. oxygen, silicon, iron e. melts, minerals, rocks

crust, mantle, core

Melting that occurs due to a decrease in pressure is called: a. flux melting b. hot spot melting c. decompression melting d. heat-transfer melting e. impact melting

decompression melting

Why are there so many types of magma? Select all that apply a. different magmas may mix to form a new magma b. the lava which forms magmas may cool at different rates c. the process of partial melting tends to form magmas which are more mafic d. the source rock from which magmas form may differ e. magmas may assimilate different chemicals once they reach the surface

different magmas may mix to form a new magma, the source rock from which magmas form may differ

Which of the following is NOT part of an atom? a. proton b. neutron c. element d. nucleus e. electron

element

Given the shape of Mt. St. Helens volcano and the presence of a lava dome (source of steam) what is the most likely composition of the associated magma? a. mafic b. no relationship between these features and composition c. ultramafic d. felsic/intermediate

felsic/intermediate

The process by which mafic inerals freeze first in a melt, leaving behind a more felsic magma, is called: a. fractional crystallization b. viscosity c. magma mixing d. assimilation e. partial melting

fractional crystallization

Why does magma rise from depth to the surface of the earth? select all that apply: a. it is less dense than the rocks that surround it b. the surrounding rock creates pressure that pushes it upward c. earths rotation causes it to accelerate until it cannot go elsewhere d. it is a liquid and liquids always float atop solid objects

it is less dense than the rocks that surround it, the surrounding rock creates pressure that pushes it upward

Which of the following represents the LEAST significant volcanic hazard to humans in terms of potential loss of life? a. pyroclastic flows b. lahars c. lava flows d. toxic gases e. tsunamis

lava flows

Marine magnetic anomalies result from sea-floor spreading in conjunction with: a. apparent wander of the magnetic poles b. magnetic polarity reversals c. magnetic storms on the surface of the sun d. global warming

magnetic polarity reversals

Hot spot volcanoes occur where? a. mainly at mid ocean ridges b. mainly on continental lithosphere c. mainly on oceanic lithosphere d. mainly above subduction zones e. mainly in plate interiors

mainly in plate interiors

Which of the following is NOT essential in defining a mineral? a. man-made b. crystalline structure c. definable chemical composition d. formed by geologic processes e. solid material

man-made

Which of the following are methods used by geologists to predict volcanic eruptions (select all that apply)? a. measuring a decrease in gas and steam emissions b. measuring an increased occurrence of gaseous emissions c. observing changes in the shapes of volcanoes d. measuring an increased incidence of earthquakes e. measuring an increase in heat flow

measuring an increased occurrence of gaseous emissions, observing changes in the shapes of volcanoes, measuring an increased incidence of earthquakes, measuring an increase in heat flow

___ that do not completely vaporize in the atmosphere impact the earth and are termed ___ a. meteors; asteroids b. asteroids; meteorites c. meteorites;meteors d. meteors; meteorites

meteors; meteorites

Where do you find black smokers?

mid ocean ridges

Which is NOT associated with a convergent plate boundary? a. accretionary prism b. volcanic arc c. subduction zone d. mid-ocean ridge e. earthquakes

mid-ocean ridge

The boundary separating the crust from the mantle is called the: a. lithosphere b. heliosphere c. moho d. asthenosphere

moho

According to the theory of plate tectonics, the plates are (check all that apply) a. significantly more plastic than the rigid asthenosphere atop which they float b. moved by the creation of new crust and subduction of old crust c. linked pieces of lithosphere which float atop the asthenosphere d. composed of either continental or continental and oceanic lithosphere e. discrete pieces of lithosphere which move with respect to one another

moved by the creation of new crust and subduction of old crust and discrete pieces of lithosphere which move with respect to one another

Which of the following does not develop at a convergent boundary? a. trench b. volcanic arc c. new oceanic lithosphere d. accretionary prism

new oceanic lithosphere

According to the plume model for oceanic hot-spot volcanoes, volcanic activity: a. occurs at many volcanoes at the same time, along a hot-spot track b. produces a volcanic islands which never sink below sea level c. occurs at a given point on the surface of the plate until that point has moved far off the plume so the volcanic conduit breaks d. results in continuous, uninterrupted ride of volcanic rock

occurs at a given point on the surface of the plate until that point has moved far off the plume so the volcanic conduit breaks

Where is the ocean floor at the greatest water depth? a. mid ocean ridge b. continental shelf c. oceanic trenches d. abyssal plain e. about 500 km from the spreading center

oceanic trenches

Which of the following statements about plutons is correct? a. plutons form at depth, where they cool slowly b. in some climates, the igneous rock comprising plutons is relatively resistant to erosion, so they remain as hills c. plutons have a tabular shape, like a wall or table top d. plutons form at the earths surface by extrusion and are then buried deeply

plutons form at depth, where they cool slowly, in some climates, the igneous rock comprising plutons is relatively resistant to erosion, so they remain as hills

One type of volcanic hazard buries crops, spreads toxic chemicals, and destroys moving parts in machinery. This type of hazard is: a. pyroclastic ash b. a lahar c. a lava flow d. poisonous volcanic gas

pyroclastic ash

How is a lahar different from a pyroclastic flow? a. pyroclastic flows are always basaltic, whereas a lahar is always silicic b. pyroclastic flows are found mainly at volcanoes that are covered with snow and ice c. pyroclastic flows are mixtures of debris and air, whereas a lahar is a fast, liquid flow d. lahars are mixtures of debris and air, whereas pyroclastic flows are a liquid mixture of lahar debris

pyroclastic flows are mixtures of debris and air, whereas a lahar is a fast, liquid flow

The textbook attributes that tectonic plate movement is driven directly by a. ridge-push force b. slab-pull force c. mantle convection d. ridge-push force and slab-pull force e. all answers are correct

ridge-push force and slab-pull force

A form of subaerial volcano is a gently sloped dome typically composed of basaltic volcanic rock. Is it a: a. shield volcano b. stratovolcano c. cinder cone

shield volcano

Most magmas contain: a. silica b. carbon c. water d. calcium e. all of the above

silica

The most abundant minerals on earth are from which class? a. silicates b. carbonates c. native metals d. halides e. oxides

silicates

Explosive volcanic eruptions do not produce lava flows because: a. the sudden release of accumulated gas pressure blasts the lava upward forming pyroclastic debris b. the overriding plate at the subduction zone where the volcano formed is composed of oceanic lithosphere c. the lava produced cools too quickly due to the abundant water in the surrounding environment d. the gases below the surface rise and cause the magma to cool and solidify

the sudden release of accumulated gas pressure blasts the lava upward forming pyroclastic debris

What accounts for more than 99% of the mass of our solar system ? a. sun b. terrestrial planets c. Jupiter d. interstellar dust e. asteroids

the sun

Gemstones are valuable because: a. they form deep inside the earth b. they are rare and unusual c. they are sold by jewelers d. they are transparent crystals e. they form from the solidification of magma

they are rare and unusual

What type of plate boundaries do earthquakes occur at? a. convergent b. divergent c. transform

transform

Which of the following are the primary gases that erupt from volcanoes? a. water vapor b. oxygen c. carbon monoxide d. carbon dioxide e. hydrogen sulfide f. sulfur dioxide

water vapor, carbon dioxide, hydrogen sulfide, sulfur dioxide