geology final

Tectonic plates move at rates that are approximately ________.

1 to 15 cm/year

According to the figure below, approximately how much has the sea level risen since the last ice age ended, approximately 16,000 years ago?

110m

If a 50-year flood occurs on the Mississippi River this year, what is the probability that a flood of the same magnitude will occur in the following year?

2%

Sea level is currently rising at 3.3 mm/yr, and scientists predict that global warming could cause a rise in sea level of 7 m if left unabated. How long will it take the sea to rise 7 m at the current rate?

2,121 years

Models used by the Intergovernmental Panel on Climate Change show that by the year 2100, the sea level may rise by as much as ________.

20-60 cm

What is the percentage of dissolved salt in seawater?

3.5%

Models used by the Intergovernmental Panel on Climate Change show that by the year 2100, the average annual temperature will have increased in some parts of the world by as much as ________.

4°C

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

70%

The reliable paleoclimate record from the Antarctic and Greenland ice cores provides information back to approximately ________ years ago.

700,000

The figure below shows the transmission, absorption, and reflection of radiation from various sources. In which layer (A, B, or C) do greenhouse gases accumulate?

A

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

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

Which of the following is NOT true concerning the color of minerals?

A mineral's color reflects the wavelengths of light that are absorbed by the mineral

How does the formation of oil shale deposits, coals, and limestones effect the carbon dioxide (CO2) concentration in Earth's atmosphere?

All three decrease the total CO2 in the atmosphere.

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

Amazon

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 ________.

B; width

How are bicarbonate and carbon dioxide (CO2) related to one another?

Bicarbonate forms when CO2 molecules dissolve in water.

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

C and D

The figure below shows parts of the global carbon cycle. Which chemicals are also parts of the carbon cycle?

CH4 (methane), HCO3- (bicarbonate), and CaCO3 (calcite)

In the figure below, why is there a seasonal variation in carbon dioxide (CO2) concentrations?

CO2 concentrations rise and fall as photosynthesis decreases and increases.

How are carbon dioxide (CO2) levels in the atmosphere affected by tectonic uplift of rocks and their resultant chemical weathering?

CO2 is removed from the atmosphere.

A crater in Mexico's Yucatan peninsula may be the result of an impact that brought about the extinction of numerous species at the end of the ________ Period.

Cretaceous

Which of the following figures shows a coast experiencing high tide?

D

Why does differential weathering occur?

Different minerals have different resistances to weathering.

How are pollen species used to interpret ancient environments?

Different plant species live in different climates.

In the figure below, which letters represent the wave height and wavelength?

E and B

Over 2,000 years ago, an ancient Greek astronomer concluded (correctly) that the ________.

Earth is spherical

How are greenhouse gases like carbon dioxide and methane different from other atmospheric gases like nitrogen and oxygen?

Greenhouse gases are more efficient at absorbing thermal energy and re-radiating it than the other atmospheric gases.

Which greenhouse gas has the greatest total importance in retaining radiant energy from Earth?

H2O (water)

At which of the following does a famous example of hot-spot volcanism occur?

Hawaii

As more ice in the Arctic Ocean melts, what effect does this have on the water?

Heat absorption increases as the albedo decreases.

The term and concept of seafloor spreading (see figure below) was developed by ________.

Hess and Dietz

The warmest global temperatures since the last ice age occurred in the ________.

Holocene Maximum, approximately 6,000 years ago

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

Which of the following is NOT true in regard to biochemical chert?

It is composed of the minerals calcite and dolomite.

Which of the following is true about blue-shifted light that we detect from the cosmos?

It signifies a source that is moving toward us.

The entire state of Florida is composed of fossiliferous limestone, what does this imply about Florida during the recent past?

It was a submergent coast.

Based on the figure below, how is the solar energy reaching Earth's atmosphere likely to change in the next 10 years?

It will rise.

If a dam is installed across a river, what effect will this have on the coastline?

It will starve the coast of sediment, and the beaches will disappear.

Where can icy bodies left over from the protoplanetary disk that formed our Solar System long after the Big Bang be found?

Kuiper belt

If the wind is blowing parallel to a coast, will it create an upwelling current or downwelling current?

Neither; it will enhance the longshore current.

Why do ocean water and sea ice have very different effects on air temperatures?

Ocean water absorbs solar energy much more effectively than sea ice.

Which eon of geologic time is represented by rocks containing abundant shelly fossils?

Phanerozoic

Why does physical weathering speed up the processes of chemical weathering?

Physical weathering produces fresh surfaces for chemical weathering to attack.

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

Sandstone

An important contribution made by Copernicus is his (correct) assertion that the ________.

Sun is the center of the Earth's orbit

As the velocity of flow decreases, which of the following is NOT true?

The competence increases.

You are a coastal geologist trying to help a coastal community restore its sediment-starved beach. You decide that beach nourishment is the best option, so you order that dredge sediment from the nearest river be placed on the beach. The sediment is 70% silt and 30% sand. What will be the effect of using this sediment?

The silt will be washed away by the waves, leaving the beach no better off.

How would the Coriolis affect the space station?

The space station would not be affected because it is not in Earth's atmosphere.

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.

According to the figure below, Earth's magnetic poles move constantly. About how far from the geographic poles do the magnetic poles move?

They remain in the high latitudes.

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

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

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 Ocean.

What is the difference between weather and climate?

Weather is a transient condition, whereas climate is a long-term cycle.

In the scope of plate tectonics, an active margin is defined as ________.

a continental coastline that coincides with a plate boundary

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

A runaway greenhouse effect is an example of ________.

a positive feedback mechanism

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

a straight channel; small

Which type of coastline would most likely contain estuaries or fjords?

a submergent coastline

Currently, most geologists ________.

agree that continental drift occurs due to mechanisms at work in the ocean basins and upper mantle

The amount of solar energy reflected by a surface is known as ________.

albedo

A mixture of copper and tin would be called a(n) ________.

alloy

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

alluvial fan

Natural carbon sinks have generally matched the production of carbon dioxide until ________.

approximately 1900

Which two gems are special versions of the common mineral corundum (Al2O3)?

aquamarines and emeralds

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

Major oceanic surface currents travel ________.

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

The greenhouse effect is caused by ________.

atmospheric gases, which trap heat radiated from Earth's surface

Consult the figure below. The region of thermally metamorphosed rock surrounding a cooled pluton is called a(n) ________.

aureole

Beach sediments travel ________ the ocean during a transgression and ________ the ocean during a regression.

away from; toward

The surfaces named contacts #2 and #3 are examples of ________.

baked contacts

The lowest elevation to which a stream can downcut is the ________.

base level

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

Why is a spring tide so much higher than a normal high tide?

because the Sun is aligned with the moon

The image below shows a mineral with hydrochloric acid applied to it. What mineral is this?

calcite

Limestone reefs and salt deposits are important rocks in the reconstruction of Earth history because they ________.

can be used to infer the ancient climate of the Earth; they are deposited in environments that are restricted to warm climate

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

cannot occur in successive years

Which greenhouse gases play the most significant role in influencing changes in global atmospheric temperature?

carbon dioxide and methane

The hole in the ozone layer has been brought about by anthropogenic emissions of ________.

chlorofluorocarbons

Thermohaline circulation carries ________ water from the poles to the equator, where the water becomes ________.

cold; warm

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

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

continental shelves

Which portion of the seafloor is most steeply sloped?

continental slopes

As compared to coarse-grained igneous rocks, fine-grained igneous rocks ________.

cool and solidify more quickly

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

cool more slowly

As compared to the asthenosphere, the lithosphere is ________.

cooler and less able to flow

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

cosmology

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

Which of the following is NOT one of the three major rock groups?

crystalline

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

Cycles of sea level rise and fall often create sandstone at the base, grade up into coal, and are called ________.

cyclothems

Most industrial nations have intentionally decreased their production and use of refrigerants and other chlorofluorocarbons in the last 20 years to address the ________.

decrease in atmospheric ozone over the Antarctic

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

decreasing; increasing

In uniform sediments with a relatively constant and gentle slope at the surface, a ________ drainage network is expected.

dendritic

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

Which of the following represents a unidirectional change in the nature of Earth?

differentiation of the layers of Earth

The lithosphere of the Earth is generally thinnest at ________ plate boundaries.

divergent

Glass is different from a mineral because it ________.

does not have atoms arranged in an orderly pattern

When limestone becomes chemically altered so that half of the calcium atoms are replaced by magnesium, the resultant rock is termed ________.

dolostone

Differential stress will cause crystals to align in a preferred orientation unless the crystals are ________.

equant

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

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

exceptionally coarse grained

If you found tuff deposits at an ________ igneous setting, you could conclude that the source magma had a ________ viscosity.

extrusive; high

The figure below shows changes in sea level since the last ice age ended. Based on this, if Earth were to enter another ice age similar to the last one, what would the sea level most likely do?

fall about 120 m

Which type of global change is reversible?

flooding of the continents because of global warming

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

floodplain

Rip currents ________ the shoreline.

flow directly away from

Longshore currents ________ the shoreline.

flow parallel to

Rocks resulting from thermal (contact) metamorphism will NOT possess ________.

foliation

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

foliation

Pirate streams ________.

form when headward erosion causes one stream to intersect another

According to the figure below, how much has atmospheric carbon dioxide (CO2) increased in parts per million (ppm) in approximately the last 50 years?

from about 320 to 400 ppm

The slope of a stream surface measured between two points along its course is the ________.

gradient

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 headlands

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

had reversed polarity

Meandering streams ________.

have a channel that is highly sinuous (curvy)

Look at the two conceptual examples of light waves shown below. These two waves ________.

have different wavelengths

Ephemeral streams ________.

have flowing water either episodically or during only a portion of the year

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

higher

The base level of a tributary would become ________ if a dam and a reservoir were constructed where it flowed into a trunk stream.

higher

Because of the Doppler effect, a light- or sound-emitting object moving toward you has a ________ compared to a stationary object.

higher frequency

Consult the figure below. Hawaii is an example of ________.

hot-spot volcanism

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

hydrogen and helium

The region below a streambed where groundwater flows in the same direction as the stream but at a slower rate is termed the ________ zone.

hyporheic

If a rock is melted, then erupted at the surface and cooled, then eroded and deposited, what two rock types are involved in the sequence?

igneous and sedimentary

Thermal (contact) metamorphism occurs ________.

in areas surrounding igneous intrusions

The deepest segments of the ocean floor are found ________.

in trenches associated with subduction zones

A blogger writes that global warming is not real, noting that his or her city had its coldest ever-recorded temperature last winter. The correct statement would be that the blogger is ________.

incorrect, because global warming is measured only during the summer

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

The primary cause of recent global warming is believed to be ________.

increased burning of fossil fuels

Along beaches, groins have ________.

increased erosion rates immediately down current from the groin

Regional metamorphism ________.

is another name for dynamothermal metamorphism

The stream gradient of most rivers ________.

is greater near the source than near the mouth

Continental lithosphere ________.

is thicker than oceanic lithosphere

You have been given the extraordinary opportunity to take Alvin (a submersible) down into the Atlantic Ocean to examine how the seafloor sediments have changed throughout geologic history. You can use Alvin in only one location, however. Where do you pick to visit to get the most out of your trip inside Alvin?

just off the coast of North America

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

laminar

Which of these is the longest-lasting sink for carbon dioxide?

limestones

The sea surface salinity is ________ at the mouth of the Amazon River and ________ in the Dead Sea.

low; high

A majority of the melts in the Earth form through the partial melting of ultramafic mantle rock. These newly formed magmas are ________

mafic

The difference between magma and lava is ________.

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

What does an ordinary compass indicate?

magnetic north

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

Evidence that the South American and African continents were once joined includes evidence from their coastlines such as ________.

matching fossil distributions

At a subduction zone, the overriding plate ________.

may be composed of either oceanic or continental lithosphere

What must occur in order to create an igneous rock?

melting

Injecting hot fudge into ice cream and causing the ice cream to melt is an appropriate analogy for which cause of magma melt?

melting due to heat transfer from rising magma

What type of rock is formed from deep burial?

metamorphic

A buried body of shale is subjected to differential stress, causing clay minerals to realign and produce slate. This is an example of ________.

metamorphism

Chemical and biochemical rocks are classified primarily on the basis of ________.

mineral composition

Dissolution occurs when ________.

minerals are dissolved into water

Bioturbation is the ________

mixing of sediment by burrowing organisms

In general, when rock is partially melted, the chemistry of the melt is ________.

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

Oxygen-18 and oxygen-16 are useful in studying past climates because ________.

more oxygen-18 is stored in glacial ice when temperatures drop

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

more; more

At the equatorial ocean basins, the sea surface temperatures may reach 25°C or greater. What is the range of temperatures for the seafloor, approximately 45 km below?

near freezing (1°C2°C)

The current scientific explanation for the origin of planets, moons, asteroids, and comets is the ________.

nebular theory

Thermal (contact) metamorphism produces ________.

nonfoliated rocks only

A heavy book is placed on top of a ball of pizza dough, causing the dough to flatten. This is an application of ________.

normal stress

Runoff is NOT commonly derived from ________.

ocean currents

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

olivine

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

on the inner banks of the meander

A wave will disturb the water to a depth equal to ________.

one-half of its wavelength

Milankovitch cycles describe variation in Earth's ________.

orbit and tilt

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

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

parallel

Which type of drainage network is associated with badlands topography?

parallel

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

passive

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

passive margins

The ratio of oxygen-16 and oxygen-18 isotopes in plankton fossils in deep-sea sediments can be used to determine ________.

past temperatures

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 east of your house

Which process removes carbon dioxide from the atmosphere?

photosynthesis

Stoping by magmas occurs when ________.

pieces of surrounding country rock are broken off and assimilated

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

In the last few decades, global warming has been most strongly affecting climate and wildlife of ________ regions.

polar

The primary difference between breccia and conglomerate is that conglomerate ________.

possesses more rounded grains than breccia

When a solution becomes oversaturated, new solid particles are said to ________.

precipitate from the solution

Preexisting rock that is subsequently altered to form a metamorphic rock is termed a ________.

protolith

Bombs, ash, and cinders are all examples of ________

pyroclastic debris

Two common metamorphic rocks that typically lack foliation are ________ and ________.

quartzite; marble

Along a large cone-shaped volcano, a ________ drainage network is expected.

radial

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

radial

Numerical ages for boundaries between time units on the geologic time scale primarily resulted from the study of ________, in conjunction with relative age data.

radiometric dating of igneous rocks

In a region with prominent orthogonal sets of joints, a ________ drainage network is expected.

rectangular

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

rectangular

Waves ________.

refract so as to impact the shore in a nearly parallel manner

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

river current exceeds the oceanic current

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

sea level

Most continental topography lies within a range of altitude between ________.

sea level and 1 km above sea level

A fine-grained clastic sedimentary rock that splits into thin sheets is ________.

shale

Siltstone or mudstone containing marine fossils likely formed in a ________ environment.

shallow-marine

The most common minerals within Earth are ________.

silicates

Volatile materials can exist as a gas at Earth's surface. Which of the following is NOT a volatile material?

silicon

On either side of a mid-ocean ridge, the lithosphere begins to ________.

sink because it cools and contracts

In regard to the cooling of molten rock, a ________ volume and a ________ shape cool faster.

smaller; pancake

An aurora (shown below) is produced when ________.

solar wind particles are directed toward the magnetic poles and excite atmospheric gases

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

solidify at lower temperatures

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

If sea level continues to rise and covers the city of Miami, the Florida coast will become a(n) ________.

submergent coast

Earth's magnetic reversals are likely due to ________.

tectonic plates shifting

Which of the following is NOT a factor controlling the cooling rate of magma?

tectonic setting

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

thalweg

The distinction between a valley and a canyon is ________.

that the sides of a canyon are more steep than those of a valley

At which of the following does an island volcanic arc occur in the present day?

the Aleutian Islands of Alaska

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

the Atchafalaya River

Which modern sea do geologists believe might have filled very rapidly with ocean water when rising sea levels overtopped a small land bridge or a natural dam?

the Black Sea

The hydrologic cycle includes which of these?

the advance and retreat of glaciers

A triple junction, like the one shown below, is a place on Earth's surface where ________.

the boundaries of three lithospheric plates meet at a single point

Sedimentary sequences, which are bounded by unconformities, record global sea level rise and fall with variations in ________.

the coarseness of clastic sediments/sedimentary rocks

Barrier islands are constantly moving in the direction of ________.

the longshore drift

Which of the following would be an area of the ocean with the least dense water?

the mouth of the Amazon River

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

Concerning the relative ages of the granite and sandstone, ________.

their relative ages cannot be determined from the information given

By deep-sea drilling, the Glomar Challenger proved the theory that if the model of seafloor spreading was correct, then seafloor sediment should be ________ and ________ as one moves away from the spreading axis.

thicker; older

If the climate in an area has very little rainfall, what would be the characteristics of the soil in the area?

thin, with very little organic material

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

thinner

Evidence that glaciers once covered an area might include ________.

till and striations

In the figure below, which way is the wave moving?

to the left

A biogeochemical cycle refers to the ________.

transitioning and the residence of specific chemicals among living and nonliving systems

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

travertine

In a region characterized by a parallel series of ridges and valleys, a ________ drainage network is expected.

trellis

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

trellis

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

The castle on the island of Mont Saint-Michel, France, can be accessed ________ a day during ________ tide, but ________ during neap tide.

twice; low; never

The presence of liquid water on Earth's surface is ________.

unique in the Solar System; liquid water would not have developed had Earth been much closer to or much farther from the Sun

Which of the following is an important long-term (i.e., spans tens of millions of years) factor in global climate change?

variation in Milankovitch orbital parameters

Which geologic event is NOT suspected as a source of major climate change and mass-extinction events?

very large earthquakes

Which of the following processes releases carbon dioxide into the atmosphere?

volcanism

During most of the Mesozoic Era, Earth was ________.

warmer than present

With the increased data collected in recent years, scientists have become increasingly certain that Earth's climate is ________.

warming as a result of human inputs of atmospheric greenhouse gases

Increasing ratios of oxygen-18 to oxygen-16 in glacial ice indicate ________.

warming temperatures

Very early in Earth's history (during the Hadean Eon), the Earth ________.

was so hot that it was, at times, completely molten

In the figure below, which direction is the longshore drift?

west

If a beach is in an east-west orientation and the waves are approaching the shore from a southeasterly direction, in which direction will the longshore drift be?

western

The shape of a delta is primarily determined by ________.

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

Hot spots can occur ________.

within either continental or oceanic plates