GEO FINAL EXAM

What is the percentage of dissolved salt in seawater?

3.5%

The circumference of Earth is most nearly ________.

40,000 km

Approximately what percentage of Earth's surface is covered with water?

70%

the figure below shows two hypothetical streams that have identical cross-sectional areas but different channel shapes. Assuming all other factors are equal, stream ________ will have the fastest flow because of the difference in ________

A; wetted perimeter

Evidence of paleomagnetism can be found in ________

All of the above are correct.

Which river has the greatest discharge of any stream on Earth?

Amazon

Which river is a threat to capture the flow of the Mississippi River through stream piracy?

Atchafalaya River.

Using the figure below, which of the following lists correctly identifies the various seafloor landforms?

B = continental shelf, A = continental slope, C = continental rise, G = abyssal plain, D = mid-ocean ridge, F = trench, and E = volcanic ar

In the figure below, which letters represent the crest and trough?

C and D

Why does differential weathering occur?

Different minerals have different resistances to weathering

the flat-lying area surrounding a river channel is termed the ________

Floodplain

Your professor's last name in this class is:

Harris

Mid-ocean ridges (MORs), which are the sites of new oceanic crust formation, are linear mountain chains that run along divergent plate boundaries. Why does an MOR sit up higher than the surrounding oceanic crust?

Hot materials are less dense and expand; thus, the new crust will sit higher than the surrounding crust.

________ commonly serves as a protolith in the formation of marble.

Limestone

What is a primary difference between phyllite and schist?

Mica crystals within schist are larger than those within phyllite.

The boundary between the crust and the mantle is marked by an abrupt change in seismic velocity called the ________

Moho

Within a meander, where is sediment most likely to be deposited?

On the inner banks of the meander

________ commonly serves as a protolith in the formation of quartzite.

Sandstone

________ commonly serves as a protolith in the formation of slate.

Shale

The deepest part of a curved stream channel, where the flow is fastest, is called the ________.

Thalweg

At a river delta, which of the following is NOT true?

The stream channel becomes very straight because of the large sediment load.

Why is the surface salinity in the tropics so much higher than that of the equator or high latitudes?

There is a higher evaporation rate and a lower rate of precipitation in the tropics.

What will eventually happen to the headlands in the figure below?

They will become a straight line of cliffs as rock is eroded away.

The image below shows a cross-sectional view of a typical subduction zone, with earthquake locations shown with small dots. The band of earthquakes that follows the shape of the downgoing plate is termed the ________

Wadati-Benioff zone

Scientists believe that approximately 60 million years ago the closing of the Isthmus of Panama changed the climate of Earth so severely that winters in Europe became 10°C warmer than they had been. Why did this happen?

Warm Caribbean Sea waters were forced up into the north Atlantic Oce

The density of seawater increases with ________ in temperature and ________ in salinity.

a decrease; an increase

What physical property of the underlying rock would lead to the formation of a cliff over which a waterfall may form?

a high resistance to erosion

Which of these parts of the deep-ocean floor is flat and nearly featureless?

abyssal plain

Most of the ocean floor is made up of ________.

abyssal plains (4 to 5 km below sea level)

The figure below shows a road in Death Valley, California, curving around a(n) ________.

alluvial fan

The youngest sea floor is typically found ________

along mid-ocean ridges

A guyot is ________.

an extinct oceanic hot-spot volcano that has subsided below sea level

During a journey to the center of the Earth, one would experience temperature ______

and pressure both increasing

Igneous rocks ________.

are formed through the freezing or crystallization of a melt

A clastic rock composed of sand-sized grains derived from the physical weathering of granite and containing a sizable proportion of feldspar is termed ________

arkose

The lithosphere lies directly above the _______

asthenosphere

Major oceanic surface currents travel _______

at an angle to prevailing winds as a result of the Coriolis effect

Precambrian metamorphic rocks are exposed at the surface ________.

at places in continental interiors termed shields

Beneath a blanket of sediments, oceanic crust is primarily composed of ______

basalt

The form and topography (depth profile) of the ocean floor is termed ________.

bathymetry

Which environment would most likely produce sedimentary deposits characterized by very well-sorted, very well-rounded grains that are nearly pure quartz?

beach

If one were to ride a hot air balloon up into the atmosphere, one would experience the concentration of gases ________.

becoming less dense

Geologists call individual layers of sedimentary rocks ________, whereas severalof them together are called ________.

beds; strata

Cemented shells of marine organisms form which kind of sedimentary rock?

biochemical

The rapid, deep burial of sediments in an accretionary prism leads to the formation of a metamorphic rock termed ________.

blueschist

Which of the following is NOT true? A 100-year flood ________

cannot occur in successive years

Which of the following are NOT considered sediments?

cemented grains

Broadly, metamorphism involves ________.

changes in mineralogy and texture in response to heat and stress

Lithified detritus (breakdown products of preexisting rocks) forms which kind of sedimentary rock?

clastic

As compared to aphanitic igneous rocks, phaneritic rocks are _______

coarser grained

The image below shows an outcrop of coarse-grained sedimentary rock. Note the rock hammer for scale. What is the name of this rock type?

conglomerate

Braided streams ________.

consist of a series of intertwined channels that are overloaded with sediment

Ephemeral streams ________.

consist of a series of intertwined channels that are overloaded with sediment

The shallowest portions of an ocean found along the margins of continents are the ________.

continental shelves

As compared to the asthenosphere, the lithosphere is _______

cooler and less able to flow

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

core

Consult the figure below. Here, distinct internal laminations are inclined at an angle to the boundary of the main sedimentary layers. This is termed ________

cross beds

From left to right, correctly label each section of this slice of the Earth. Note that 1 starts at the surface of the Earth and 6 ends at the center of the Earth.

crust, upper mantle, transition zone, lower mantle, liquid outer core, solid inner core

In the formation of gneiss from granite, distinctive compositional bands form because of ________.

crystals dissolving, with atoms and ions migrating and reorganizing as new crystals

The outer edge of a meander, where material is being eroded, is a(n) ________.

cut bank

The figure below shows an example of a ________ drainage network

dendritic

Compared with the continental crust, the oceanic crust is ________.

denser

The mineral assemblage within metamorphic rock is _______

dependent on both the mineral content of its protolith and the temperature and pressure of formation

The application of ________ during metamorphism causes elongated crystals to align parallel with each other. When this happens, the rock develops ________

differential stress; foliation

In the figure provided below, what type of igneous intrusion is the horizontal rock unit shown by letter A?

dike

In the figure provided below, what type of igneous intrusion is the vertical rock unit shown by letter A?

dike

Which basic type of plate boundary is shown in the image below?

divergent

The removal of detritus from weathered rock at an outcrop is termed ________.

erosion

When the sea level rises, an ocean may invade a river valley, producing a nearshore body of water of mixed and variable salinity termed a(n) ________.

estuary

Which type of magma has the greatest silica content?

felsic

The density of rocks is generally related to composition. Which of the following choices places rock compositions in order of increasing density?

felsic, intermediate, magic, ultramafic

Rip currents ________ the shoreline

flow directly away from

Longshore currents ________ the shoreline

flow parallel to

Slaty cleavage, schistosity, and compositional banding are all examples of ________.

foliation

Which of the following statements is NOT true? Hornfels facies ________

form at high pressures but low temperatures

Pirate streams ________.

form when headward erosion causes one stream to intersect another

As compared to the rocks that make up the crust, Earth as a whole is ______

greater proportion of silica

As compared to ultramafic rocks, mafic rocks have a _______

greater proportion of silica

A small mountain stream will have a ________ competence and a ________ capacity than the Mississippi River.

greater; lower

Because of wave refraction, erosion along an irregular coastline is ________.

greatest along headland

Meandering streams ________.

have a channel that is highly sinuous (curvy)

High tide will be ________ during a full moon than normally.

higher

Consult the figure below. Hot water reacting with the crust is the basis for what type of metamorphism?

hydrothermal

Which transport medium carries the largest particles?

ice in glaciers

Thermal (contact) metamorphism occurs ________.

in areas surrounding igneous intrusions

The deepest segments of the ocean floor are found ________.

in trenches associated with subduction zone

All other factors equal, if a body of magma becomes more felsic, its viscosity will _______

increase

The discharge of a river traveling through a temperate region will typically ________ downstream; the discharge of a river traveling through an arid region will typically ________ downstream

increase; decrease

Along beaches, groins have ________.

increased erosion rates immediately down current from the groin

With increasing distance from a mid-ocean ridge, the age of oceanic crust _______

increases

A mineral within a metamorphic rock that can be used to provide a narrow constraint on the temperature and pressure of rock formation is termed a(n) ________ mineral

index

The densest layer of Earth is the _______

inner core

Chemical weathering involves the breakdown of material due to ________.

interaction with water or air

Unlike the lithosphere, the asthenosphere ________.

is able to flow over long periods of time

at a subduction zone, the downgoing (subducting) plate ______

is always composed of oceanic lithosphere

Regional metamorphism ________.

is another name for dynamothermal metamorphism

The Moho ________

is found deeper underneath continents than under oceans

The stream gradient of most rivers ________.

is greater near the source than near the mouth

Continental lithosphere ________.

is thicker than oceanic lithosphere

Moving away from its headwaters/source, the flow of a stream usually becomes more ________.

laminar

Compaction and cementation of grains occurs during ________.

lithification

The difference between magma and lava is _______

magma is found beneath the surface, whereas lava is found at the surface

If you were using both a compass and a map marked with latitude and longitude to navigate, you might note the angle difference between your compass and what is marked on the map, called ______

magnetic declination

Marine magnetic anomalies result from seafloor spreading in conjunction with ______

magnetic polarity reversal

Where Earth's magnetic dipole intersects with the surface of the planet is called the __________

magnetic pole

V-shaped stream valleys result from the downcutting of stream erosion and _______

mass wasting on the valley sides

Dissolution occurs when ________.

minerals are dissolved into water

Saline ocean water is ________ than fresh water, and provides ________ to objects floating in it.

more dense; more bouyancy

The sedimentary rocks breccia and conglomerate most commonly form in a ________ environment

mountain stream

Eratosthenes was the first person to accurately estimate the size of Earth. He accomplished this feat by ________.

observing shadows simultaneously cast at two different cities that were separated by a known distance

Runoff is NOT commonly derived from ________.

ocean currents

A wave will disturb the water to a depth equal to _______

one-half of its wavelength

Two major sources of energy, coal and oil shale, are considered ________ sedimentary rocks.

organic

A meander that is cut off to become completely isolated from the main channel but which retains water is a(n) ________.

oxbow lake

Which type of weathering process is happening to materials when they rust?

oxidation

Along a uniform and steep slope of relatively weak substrate, a ________ drainage network is expected.

parallel

With time, a river may erode terrain to produce a low-lying plain that lies close to the base level, which is termed a(n) ________

peneplain

You have just bought your dream home along a coastline, but you notice that the beach in front of your new house is slowly disappearing. You decide to solve this by building a groin. Winds blow predominantly from east to west, so where do you place your groin?

perpendicular to the shore to the west of your house

Which of the following is NOT a mineral?

petroleum

Bowen's continuous reaction series describes the crystallization behavior of which single mineral (with variable chemical composition)

plagioclase

The inner edge of a meander, where sediment is deposited, is a(n) ______

point bar

The figure below is an aerial photograph of a meandering stream. The light-colored features labeled with arrows below are ________.

point bars

The process of low-grade metamorphic rocks being altered to form high-grade metamorphic rocks is termed ________ metamorphism

prograde

Preexisting rock that is subsequently altered to form a metamorphic rock is termed a _______

protolith

The figure below shows an example of a _____ drainage network

radial

The figure below shows an example of a ________ drainage network.

rectangular

The process of high-grade metamorphic rocks being altered to form low-grade metamorphic rocks is termed ________ metamorphism

retrograde

A well-sorted sandstone with asymmetric ripples was most likely deposited as sand by a ______

river (far from source)

A "bird's foot"delta configuration, similar to that of the Mississippi River delta, forms when the ________

river current exceeds the oceanic current

What type of weathering are you most likely to find occurring on the coast?

salt wedging

Ultimately, the base level of a stream valley can be no lower than _____

sea level

Consult the figure below. Marine magnetic anomaly belts are widest when and where ______

sea-floor spreading rates are relatively rapid

The majority of the rocks that occur at the surface of Earth are ________.

sedimentary rocks

Which of the following describes the progression of rock types through increasing metamorphic grade?

shale---> slate---> phyllite---> schist

The most common minerals within Earth are ________

silicates

When graded beds are observed in a rock outcrop, this tells geologists that a ________.

slurry deposited these beds with little sorting

All else being equal,water will flow faster in a stream that has a ________, which is typically found near the river's ________

steep stream gradient; source

All else being equal, water will flow faster in a stream with ________ and a ________ wetted perimeter.

straight channel, small

Death Valley is currently sinking partly due to the weight of continuously accumulating sediment shed from the mountains that border the valley. What phenomenon is this an example of and what depositional environment is created by the sediment deposition?

subsidence and alluvial fans

As compared with metamorphism, diagenesis ________.

takes place at lower temperatures and pressures

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

the addition of new lithospheric mantle as a result of cooling

Stratification refers to ________.

the development of layering within sedimentary rocks

Barrier islands are constantly moving in the direction of _______

the longshore drift

Geological evidence suggests that many millions of years ago, the Amazon basin drained toward the west rather than the east. What caused this drainage reversal?

the rise of the Andes Mountains

According to Archimedes' principle of buoyancy, an iceberg sinks until ________

the total mass of the water displaced equals the total mass of the whole iceberg

Compared to oceanic crust, continental crust is ________

thicker

Compared with the continental lithosphere, the oceanic lithosphere is ________.

thinner

Which basic type of plate boundary is shown in the image below?

transform

Sea level rises locally, and marine sediments are deposited on top of terrestrial sediments during events termed ________

transgressions

Chemically precipitated limestone that forms in caves or around hot springs is termed ________.

travertine

The figure below shows an example of a ________ drainage network.

trellis

The atmosphere is divided into several distinct layers. Beginning with the layer in which we live, they are, in order, ________.

troposphere, stratosphere, mesosphere, and thermosphere

The primary stream fed by tributaries within a dendritic drainage network is termed a ________ stream

trunk

The total sediment load of a stream consists of all of following EXCEPT the ________ load

turbulent

Which of the following lists compositions in order of increasing silica content?

ultramafic, mafic, intermediate, felsic

if a geologist found preserved mud cracks, he or she could conclude that the environment in which they formed ________

was once covered in wet mud

Retrograde metamorphism will not occur unless an increased amount of ________ is added to the system

water

Potassium feldspar reacts with water to form clay. This is an example of _______

weathering

The breakdown of exposed rock into small fragments and dissolved ions is termed ________.

weathering

The shape of a delta is primarily determined by _______

whether river currents, wave-driven currents, or tidal currents are locally predominant