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178 Cards in this Set

  • Front
  • Back

The geocentric model was developed during the time of the ancient Greeks. This model ____________.

was held to be true by thinkers throughout the Middle Ages, up until the Renaissance

In the heliocentric model ____________.

Earth orbits around the Sun

In our current understanding of the big bang, ____________.

the Universe is considerably older than Earth

Among the choices below, the best estimate of the age of the Universe is ____________ years old.

14 billion

The big bang theory states that ____________.

all matter in the Universe was once confined to a single point

Strong evidence that the Universe is expanding comes from the fact that the light emitted from distant galaxies appears to be ____________.

red shifted

Italian Renaissance astronomer Galileo was the first person to deduce that planets were distinct entities from stars.


Since the initiation of the Big Bang, the temperature of the Universe has


Atoms that are heavier than iron are generally produced by ____________.

the explosion of supernovae

As the Universe has evolved, ____________.

hydrogen has been lost through fusion to form helium within stars

By far the most common elements in the Universe and in our Solar System are ____________.

hydrogen and helium

Which of the following bodies is the smallest?


Aside from Earth, the terrestrial planets are ____________.

mars, mercury and venus

The gas-giant, or Jovian, planets are ____________.

Jupiter, Saturn, Uranus, and Neptune

The branch of science that studies the structure and history of the Universe is _____________.


All objects in the Solar System are in orbit around ____________.

the sun

An ancient Greek philosopher concluded (correctly) that ____________.

the earth was spherical

The circumference of Earth is most nearly ____________.

40,000 km

A light year is a unit that measures ____________.


Our Sun belongs to a galaxy known as ____________.

the milky way

In agreement with the Big Bang theory, our Universe is ____________.


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 ____________.

solar wind

Chemically, the Moon is quite similar to ____________.

earths mantle

Foucault’s experiment with a pendulum proved that ____________.

Earth rotates about an internal axis

Humans first realized that the Earth was spherical ____________.

during the time of Aristotle in ancient Greece

Differentiation of the core from the mantle early in Earth’s history was possible because the planet was ____________ at the time.

very hot

The metal alloy that makes up the core of Earth is ____________ as compared to the rocky mantle.


Earth’s surface is protected from solar wind and cosmic radiation by ____________.

Earth’s magnetic field

The shape of Earth’s magnetic field is approximately that of a ____________.

dipole (i,e. bar magnet)

Presently, Earth’s atmosphere is dominated by which two gases?

nitrogen and oxygen

In the whole Earth, the four most common elements are oxygen, silicon, magnesium, and ____________.


As compared to ultramafic rocks, mafic rocks have a ____________.

greater proportion of silica

Hot, liquid rock beneath the surface of the Earth is termed ____________.


A fracture in the crust, where rocks slide past one another, is termed a ____________.


The boundary between the crust and mantle is marked by a seismic-velocity discontinuity called ____________.

the Moho

As seismic (earthquake-generated) waves travel downward and reach the Moho, they ___________.

speed up

Earth’s magnetic field is generated by ____________.

the flow of the liquid outer core

The lithosphere is composed of the ____________.

crust and the uppermost part of the mantle

Moving into the interior of Earth, temperature ____________.

and pressure both increase

The thickness of Earth’s crust varies from ____________.


Of the three primary chemical layers of the Earth (crust, mantle, core), which is the thickest layer?


Which of Earth’s layers has the greatest density?


With increasing altitude, the concentration of gases in our atmosphere

becomes less dense

The two most common elements in the crust of Earth are

oxygen andsilicon

The metallic content of Earth’s core is ____________.


likely similar to what has been found in metallic meteorites


partly liquid and partly solid


an iron alloy (mostly iron with a few other elements mixed in)


As compared to continental crust, the rocks that make up oceanic crust are ____________.


The Moho ____________.

is found deeper underneath continents than under oceans

The lithosphere lies directly above the ____________.


As compared to the asthenosphere, the lithosphere is ____________.

cooler and less able to flow

Wegener proposed continental drift after he observed evidence from fossils, glacial deposits, and the fit of the continents that suggested all of the continents were once ____________.

combined to form a supercontinent (he termed Pangaea) in the late Paleozoic through the Mesozoic

Late Paleozoic glacial deposits are NOT found in which of the following places?

north america

Abundant swamps led to the formation of coal during the Late Paleozoic in which of the following places?

north america

Which plant genus dominated glaciated regions during the late Paleozoic and early Mesozoic?


Wegener’s idea of continental drift was rejected by American geologists because ___________.

he could not conceive of a valid mechanism that would cause continents to shift positions

Currently, most geologists ____________.

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

The magnetic field of Earth in the geologic past is ____________.

unknown, but it is assumed to have been identical to today’s

The apparent tendency of the north (or south) magnetic pole to vary in position over time is termed ____________.

polar wander

The apparent polar-wander paths for continents that were not connected over some span of geologic history will likely ____________ concerning the positions of the ancient magnetic pole.


Regions of the sea floor with positive magnetic anomalies were formed during times when Earth’s magnetic field ____________.

had normal polarity

Regions of the sea floor with negative magnetic anomalies were formed during times when Earth’s magnetic field ____________.

had reversed polarity

Marine magnetic anomaly belts run parallel to ____________.

mid-ocean ridges

Marine magnetic anomaly belts are widest when and where ____________.

sea-floor spreading rates are relatively rapid

The age of oceanic crust ____________ with increasing distance from a mid-ocean ridge.


true or false Wegener’s evidence for a united Pangaea was so compelling that virtually all geologists agreed with the idea of continental drift during his lifetime.


Distinctive rock sequences on South America terminate at the Atlantic Ocean but reappear on the continent of ____________.


If we mentally align the continents to fit Wegener’s concept of Pangaea, evidence of late Paleozoic glacial deposits ____________.

is much more readily explained than in the modern continental configuration

The apparent polar-wander path obtained from magnetite crystals in basalts on the North American continent is now interpreted to be the result of ____________.

drifting of the North American continent

T or F.The deep ocean floor is flat and nearly featureless.


Beneath a blanket of sediments, oceanic crust is primarily composed of two rocks, ____________.

gabbro and basalt

Marine magnetic anomalies result from sea-floor spreading in conjunction with ____________.

magnetic polarity reversals

The oldest sediments on the ocean floor are about ____________ years old.

200 million

The primary difference between lithospheric and asthenospheric mantle that gives rise to numerous divergent patterns of physical behavior, is ____________.

temperature (the lithosphere is cooler than the asthenosphere)

The theory of plate tectonics ____________.

incorporates and explains both sea-floor spreading and continental drift

Unlike the lithosphere, the asthenosphere ____________.

is relatively weak and flows readily

Continental lithosphere ____________.

is thicker than oceanic lithosphere

The average thickness of continental lithosphere is about ____________.

150 km

The thickness of oceanic lithosphere is ____________.

least near the mid-ocean ridges and thickens away from the ridges

Under the theory of plate tectonics, the plates themselves are ____________.

discrete pieces of lithosphere at the surface of the solid Earth that move with respect to one another

In the terminology of plate tectonics, an active margin is ____________.

a continental coastline that coincides with a plate boundary

Continental coastlines that occur within the interior of a tectonic plate are called

passivel margins

Broad, sediment-covered continental shelves are found along ____________.

passive margins

Tectonic plates might consist of ____________.

oceanic or continental lithosphere or a combination of both

Deformed (bent, stretched, or cracked) lithosphere occurs ____________.

primarily within the interiors of tectonic plates

Every plate boundary can be recognized by ____________.

the presence of an earthquake belt

Tectonic plates move at rates that are approximately ____________.

1 to 15 cm/year

At a divergent plate boundary, two opposed plates ____________.

move away from one another

At a convergent plate boundary, two opposed plates ____________.

move towards each other

Mid-ocean ridges are ____________plate boundaries.


As compared to a slowly spreading mid-ocean ridge, a rapidly spreading ridge is ____________.


All lithospheric plates are approximately the same size and contain a combination of oceanic and continental crust.


The youngest sea floor occurs ____________.

among mid-ocean ridges

Oceanic lithosphere thickens away from the mid-ocean ridge primarily due to ____________.

the addition of new lithospheric mantle as a result of cooling

Subduction zones are ___________ plate boundaries.


At a subduction zone, the overriding plate ____________.

may be composed of either oceanic or continental lithosphere

At a subduction zone, the downgoing (subducting) plate ____________.

is always composed of oceanic lithosphere

The Wadati-Benioff zone is a belt of earthquakes found ____________.

within a downgoing plate at a subduction zone

The Wadati-Benioff zone extends down within the mantle to a maximum depth of ____________.

670 km

At transform plate boundaries ____________.

earthquakes are common, but volcanoes are absent

A triple junction is a place on Earth’s surface where ____________.

the boundaries of three lithospheric plates meet at a single point

The mid-ocean ridges are elevated above the surrounding sea floor because ____________.

ridge rocks are hot and therefore of relatively low density

Hawaii is an example of ____________.

hot-spot volcanism

Segments of the mid-ocean ridge system are offset. Between the offset segments we observe ____________.

transform faults

When two bodies of continental lithosphere are pushed together at a convergent boundary, the result is ____________.

collision and mountain formation

Most of the pushing force that drives plate motion is produced ____________.

at mid-ocean ridges

Most of the pulling force that drives plate motion is produced ____________.

at subduction zones

Sea-floor spreading is driven by volcanic activity ____________.

along mid ocean ridges

Within the sea floor, the rate of heat flow is greatest ____________.

along mid ocean ridges

At a transform plate boundary, two opposed plates ____________.

slide past one another

All basalts younger than 700,000 years old ____________.

have normal magnetic polarity

Minerals utilized by humans as a source of metal are termed __________.

Ore minerals

The difference between lava and magma is that ____________.

magma is found beneath the Earth’s surface, whereas lava has reached the surface

A blob-like igneous rock body that has cooled beneath the surface of Earth is called a ____________.


A dike is ____________.

a sheetlike intrusion that cuts across preexisting layers

a still is________.

a sheetlike intrusion that lies parallel to surrounding layers of sedimentary rock

Geologically, melts are equivalent to both ____________.

lavas and magmas

Igneous rocks ____________.

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 type of rocks within Earth

all of the above

Very early in Earth’s history, it was so hot that the surface was likely entirely molten.


Radioactive isotopes, differentiation of Earth’s iron core, gravity-driven compression, and meteoric bombardment all caused early Earth to ____________.

be much hotter than at present

When magma crystallizes, ____________ are formed.

intrusive igneous rocks

The formation of magma within Earth is NOT caused by which of the following processes?

loss of volatiles to the atmosphere

The geotherm is the rate of change of ____________.

temperature with depth in Earth’s interior

If a body of magma is subjected to fractional crystallization, the rock that results is expected to be ____________.

more mafic than the magma

If the volatile content of magma is increased, its viscosity will ____________.


If a body of magma becomes more felsic, its viscosity will ____________.


All of the Earth’s internal heat was acquired very early in its history through meteoric impact and differentiation of the core. The Earth’s interior loses heat to space but does not currently receive heat through any known process.


When rock is partially melted, the chemistry of the melt is ____________.

more felsic than the original chemistry of the rock that was partially melted

A volcano emits ash, which falls from the sky, settles in layers, and is eventually cemented. The resultant rock is termed ____________.


Due to fractional crystallization and assimilation of surrounding host rock, most magmas that rise slowly through the crust evolve chemically to become ____________.

more felsic

As compared to coarse-grained igneous rocks, all fine-grained igneous rocks ____________.

cool and solidify more quickly

As compared to mafic igneous rocks, all felsic igneous rocks ____________.

solidify at lower temperatures

All other factors being equal, intrusive rocks that form deep within Earth ____________ than intrusive rocks that cool near the surface.

cool more slowly

Pegmatites, which occur in dikes, are unusual among shallow intrusive rocks in that they ____________.

possess exceptionally coarse grains

Obsidian ____________. volcanic glass


possesses conchoidal fracture


typically is felsic in composition


all of the above

Coarse-grained granite is most similar in mineral composition to fine-grained ____________.


Coarse-grained diorite is most similar in mineral composition to fine-grained ____________.


Coarse-grained gabbro is most similar in mineral composition to fine-grained ____________.


Most commonly, felsic igneous rocks ____________.

are lighter in color than mafic rocks

Stoping by magmas occurs when ____________.

pieces of surrounding country rock are broken off and assimilated

Important volatiles in magmas include ____________.

water and carbon dioxide

Which type of magma has the greatest silica content?


When rock is melted within Earth, typically the entire volume of rock is transformed from a solid state to a liquid.


In Bowen’s discontinuous reaction series, the first mineral to crystallize from a mafic melt is ____________.


Bowen’s continuous reaction series describes the crystallization behavior of a single mineral (with variable chemical composition), ____________.


An igneous rock with a mixed texture of coarse grains (phenocrysts) surrounded by fine crystals (groundmass) is termed ____________.


Which of the following is NOT a mineral?

a) petroleum (oil), which is a liquid

b) cubic zirconia, which is a synthetic diamond substitute that is not found in nature

c) ice, which is water in the solid state (and water is essential to all organic life on

d) both A and B are not minerals; however, C is a mineral

Both A (petroleum oil) and B (cubic zirconia)

Minerals are all naturally occurring solid substances with a definable chemical composition. They must also possess ____________.

A fixed crystalline structure (spatial arrangement of atoms and ions)

Two distinct minerals may have the same chemical formula.


A single mineral may take on multiple crystalline lattice structures.


Natural glass is not considered a mineral because it ____________.

Does not have fixed crystalline structure

Which common mineral is found in most kitchens?


Minerals in geodes form spectacular euhedral crystals because ____________.

the crystals have abundant room to grow in their hollow surroundings

It is rare for mineral crystals to display any sort of symmetry (invariance of pattern with respect to a transformation, such as rotation or mirror-image reflection).


Diamond and graphite are both polymorphs of pure silicon.


All minerals are held together by ionic bonds.


The most useful diagnostic property of minerals is their color in hand sample.


For the majority of minerals, the streak color obtained when the mineral is scratched against a porcelain plate is ____________.

less variable than the color in hand sample among crystals

The shininess of a mineral is a helpful diagnostic property termed ____________.


Ore minerals, such as galena and hematite, tend to be distinct in their very ____________.

great specific gravity

Cleavage in minerals refers to ____________.

a tendency to break along planes of weakness

The most abundant minerals belong to a chemical group termed the ____________.


When in contact with hydrochloric acid, which mineral gives off bubbles of carbon dioxide gas?


The silica tetrahedron that forms the backbone of all the silicate minerals is composed of silicon and what other element?


All minerals are chemical compounds (composed of more than one element).


In silicate minerals, tetrahedra may be coordinated to form ____________.

All of the above

In which type of silicate are the greatest proportion of oxygen atoms shared by pairs of adjacent tetrahedra?

framework silicates

With regard to minerals, hardness refers to ____________.

an ability to resist being scratched by other substances

Minerals that do not possess cleavage are said to possess ____________.


Gemstones are commonly found in pegmatites, which are igneous rocks that are ____________.

exceptionally coarse-grained

Topaz, with Mohs hardness of 8, is twice as hard as fluorite, with Mohs hardness of 4.


Synthetically made glass and natural quartz crystals both exhibit a fracture pattern termed ___________.


Which of the following is NOT a mineral?

a) quartz

b) diamond

c) petroleum

d) gold


The single property that can be used to identify any mineral is ____________.

none of the above; multiple properties must be used to diagnose a mineral

The color of a mineral in powdered form is termed ____________.


____________ is a mineral property defined by the density of the mineral sample divided by the density of water (e.g., 1g/).

Specific gravity

Trace amounts of impurity in a mineral can commonly produce significant differences in ____________ among individual crystals of this mineral.


Minerals are classified into groups primarily on the basis of ____________.

chemistry, specifically the anions within the chemical formula

Which of the following minerals is softest?


Which of the following minerals is hardest?