GEOG Chapter 8

Rocks that solidify and crystallize from a molten state are called ________. They form from ________, which is molten rock beneath the surface. Magma is fluid, highly gaseous, and under tremendous pressure. It is either ________ into preexisting crustal rocks, known as country rock, or ________ onto the surface as ________.

igneous; magma; intruded; extruded; lava

A batholith forms from A) intrusive igneous rock. B) extrusive igneous rock. C) metamorphic rock. D) sediment accumulation in a depression.

intrusive igneous rock.

Consider a beach environment with large, powerful waves breaking along the shore. Given the nature of this environment, which of the following sediments would be least likely to be deposited there? A) gravel and sand B) sand C) silt and clay

silt and clay

With increasing depth, the mantle becomes ________ due to greater ________. A) more plastic; pressures B) more plastic; temperatures C) stiffer; pressures D) stiffer; temperatures

stiffer; pressures

What percent of the earth's crust is composed of only eight natural elements? A) 25 B) 50 C) 75 D) 99

D) 99

An example of an intrusive igneous formation is a pluton.

True

Any rock, either igneous or sedimentary, may be transformed into a metamorphic rock, by going through profound physical and/or chemical changes under increased pressure and temperature.

True

Lithification refers to the cementation, compaction, and hardening of sediments.

True

The crust is thickest under mountains and thinnest under the oceans.

True

The earth's interior has been mapped using seismic waves.

True

The geologic cycle is powered both by exogenic and endogenic energy systems.

True

The ocean floor is created along midocean ridges.

True

The Hawaiian Islands were formed as a result of A) a rising plume of magma from the mantle. B) an oceanic-oceanic plate collision. C) a continental-oceanic plate collision. D) activity along a midocean ridge.

a rising plume of magma from the mantle.

The presence of 180-million-year-old salt domes in the Gulf Coast region of the U.S. indicates that A) the area was once volcanically active. B) the area was subjected to plate collisions, which caused metamorphism to occur. C) subsidence is now occurring due to the withdrawal of magma from the region. D) a sea used to cover the area but subsequently evaporated. E) None of these are indicated.

a sea used to cover the area but subsequently evaporated.

Approximately 90 percent of Earth's magnetic field is generated in the A) inner core. B) outer core. C) lower mantle. D) upper mantle.

outer core.

The three most abundant elements in Earth's crust are A) rock, water, and tectonics. B) magnesium, potassium, and oxygen. C) iron, aluminum, and granite. D) oxygen, silicon, and aluminum.

oxygen, silicon, and aluminum.

Coal is a fossil fuel formed from A) dead marine organisms. B) plants. C) metamorphosed mafic minerals. D) blue-green algae.

plants

The aesthenosphere can best be described as A) a rigid solid. B) a liquid. C) plastic-like. D) plasma-like.

plastic-like.

Which of the following is an example of an intrusive, igneous rock? A) volcano B) pluton C) dome D) lava flow

pluton

Which of the following is not part of the hydrologic cycle? A) transportation B) erosion C) sedimentation D) radioactive decay

radioactive decay

Convergent plate boundaries are characteristic of A) sea-floor spreading centers. B) collision zones between plates. C) lateral motions of plates. D) all plate boundaries.

collision zones between plates.

Mafic minerals are ________ minerals. A) dark colored, high density B) dark colored, low density C) light colored, high density D) light colored, low density

dark colored, high density

An unmetamorphosed dike could be composed of which of the following? A) granite B) sandstone C) obsidian D) gneiss

granite

Continental crust is basically ________, whereas oceanic crust is basically ________. A) thin; thick B) basalt; granite C) granite; basalt D) sima; sial

granite; basalt

The density of material below the Moho is ________ that above it. A) greater than B) less than C) the same as

greater than

The majority of the earth's crust is composed of ________ rock. A) igneous B) metamorphic C) sedimentary D) carbonate

igneous

The principles of buoyancy and balance, when applied to Earth's crust, helps us to explain fluctuations in Earth's outer crust, a property known as A) magnetism. B) Moho effect. C) isostasy. D) orogenesis.

isostasy.

The mineral crystals in a sill would be ________ those in a lava flow. A) larger than B) smaller than C) the same size as

larger than

Which of the following gives the correct sequence of layers in the mantle, from bottom to top? A) lower mantle; upper mantle, aesthenosphere B) aesthenosphere, mantle, upper mantle C) upper mantle, aesthenosphere, mantle D) mantle, aesthenosphere, upper mantle

lower mantle; upper mantle, aesthenosphere

The ancient roots of mountains are usually composed of ________ rocks. A) sedimentary B) metamorphic C) igneous

metamorphic

A rock transformed from any other rock through profound physical and/or chemical processes is referred to as A) sedimentary. B) metamorphic. C) igneous. D) ancient.

metamorphic.

An element or combination of elements that forms an inorganic, natural compound is called a A) tectonic rock. B) granitic compound. C) mineral. D) molecule.

mineral.

At which of the following locations is new ocean crust being formed? A) rift zones B) along collision zones between two continents C) along collision zones between two oceanic plates D) in trenches

rift zones

The history of life on Earth is chronicled in which type of rock? A) igneous B) metamorphic C) sedimentary

sedimentary

If you were driving down the highway and saw mountains composed of layered strata, you could be confident that you were looking at A) sedimentary rocks. B) extrusive igneous rock. C) a shield volcano. D) batholiths or laccoliths.

sedimentary rocks.

A laccolith is actually a large version of a ________. A) dike B) discontinuity C) sill D) batholith

sill

Which of the following is true of the aesthenosphere? A) It contains pockets of increased heat. B) It flows. C) It carries the crustal plates. D) All of these are true. E) None of these are true.

All of these are true.

Which layer of the planet forms 80 percent of Earth's total volume, and has an average density of 4.5 grams per cm2? A) continental crust B) oceanic crust C) mantle D) core

mantle

Which of the following is not a sedimentary rock? A) sandstone B) bituminous coal C) marble D) shale

marble

Marble is a familiar example of which type of rock? A) intrusive igneous B) metamorphic C) sedimentary D) extrusive igneous

metamorphic

Several large, linear lakes are forming in East Africa. This is evidence of what process? A) rifting B) subduction C) compression D) isostatic uplift

rifting

The magma that fuels and produces the volcanic activity around the Pacific Ring of Fire is derived from the A) magma extruded from rift zones that are developing along the Pacific Rim. B) rise of material that was melted in subduction zones along the Pacific margins. C) rise of magma from hot spots, such as those that formed the Hawaiian Islands. D) rise of magma along transform faults.

rise of material that was melted in subduction zones along the Pacific margins.

Three types of rock-forming processes compose the A) tectonic cycle. B) rock cycle. C) hydrologic cycle. D) mineral cycle.

rock cycle.

An assemblage of minerals bound together is called a A) granitic compound. B) mineral. C) molecule. D) rock.

rock.

Tilted layers of quartzite exposed in a mountain range indicagranitete that A) the mountain was covered with water. B) sand was deposited on a steeply sloping surface, lithified, uplifted and then exposed at the surface. C) sand was deposited, lithified, metamorphosed, uplifted and exposed. D) limestone was deposited, lithified, metamorphosed, uplifted and exposed.

sand was deposited, lithified, metamorphosed, uplifted and exposed.

Limestone is an example of which type of rock-forming process? A) sedimentary B) metamorphic C) igneous

sedimentary

Salt is an example of ________ rock. A) sedimentary B) extrusive igneous C) metamorphic D) intrusive igneous

sedimentary

Silt and clay are likely to be deposited in a beach environment.

true

The transition zone from the outer core to the mantle is ________ and is known as the ________ discontinuity. A) uneven; Gutenberg B) uneven; Moho C) smooth; Gutenberg D) smooth; Moho

uneven; Gutenberg

Which of the following are located along the midocean ridges? A) volcanoes B) outcrops of granite C) old oceanic sediments D) evaporite deposits

volcanoes

Which of the following is not true regarding Earth's magnetic field? A) It causes magnetic particles in cooling magma to align with magnetic field lines. B) Transition periods, during which reversals occur, last an average of about 4000 to 8000 years. C) The earth's magnetic field will probably reverse in the next few thousand years. D) A given field orientation can last billions of years.

A given field orientation can last billions of years.

Which of the following lists is in the correct sequence from youngest to oldest? A) Holocene, Pleistocene, Pliocene, Miocene B) Holocene, Precambrian, Cenozoic C) Paleozoic, Cenozoic, Mesozoic D) Tertiary, Quaternary, Cretaceous

A) Holocene, Pleistocene, Pliocene, Miocene

Which of the following statements about Earth's core is not true? A) It is composed primarily of iron. B) The inner core is believed to be liquid and the outer core solid. C) Temperatures in the core reach several thousand degrees. D) Temperatures and pressures are higher in the inner core than in the outer core.

B) The inner core is believed to be liquid and the outer core solid.

The idea that Earth formed only a few thousand years ago is A) basically accepted today by science. B) based on little physical evidence and is more appropriately considered a belief. C) referred to as uniformitarianism. D) the basis of the geologic time scale.

B) based on little physical evidence and is more appropriately considered a belief.

Which of the following lists the correct sequence of divisions in the geologic time scale, from largest to smallest? A) era, eon, epoch, period B) eon, era, period, epoch C) epoch, era, eon, period D) period, eon, era, epoch

B) eon, era, period, epoch

The heat that melted the early Earth was derived from A) nuclear fusion. B) radioactive decay. C) chemical reactions. D) sunlight.

B) radioactive decay.

When geologists or archaeologists dig downward into a unit of rock or sediment, they are digging "back in time." This fact is based on the principle of ________. A) uniformitarianism B) superposition C) catastrophism

B) superposition

Tectonic forces A) erode the surface of the earth. B) warp, fold, and uplift rock. C) control soil formation processes. D) form sedimentary rock.

B) warp, fold, and uplift rock.

Alfred Wegner's theory of continental drift was immediately accepted by the scientific community when it was proposed.

False

Earth's magnetic field is generated from within the entire planet, rather than in a specific region of Earth's interior.

False

Earthquake and volcanic occurrences do not correlate well with crustal plate boundaries.

False

Scientists recently succeeded in drilling through the crust to reach the mantle.

False

The deepest places in the ocean are those in which rifting occurs.

False

The principle of isostasy refers to the horizontal movement of Earth's plates in response to loading and unloading of weight, such as ice or sediment.

False

The uppermost mantle is plastic-like, whereas the aesthenosphere is rigid.

False

The sea-floor spreading center that led to the formation of the Atlantic Ocean accelerated dramatically between A) 4.6 and 2 billion years ago. B) 465 and 225 million years ago. C) the end of the Pleistocene and today. D) 135 and 65 million years ago.

135 and 65 million years ago.

Pangaea is currently dated at A) 4.6 billion years ago. B) about half the timespan of Earth's existence. C) 225 to 200 million years ago. D) 65 million years ago. E) the beginning of the Holocene.

225 to 200 million years ago.

The thickness of Earth's crust ranges from A) 5 km to 60 km (3 mi to 37 mi). B) 70 km to 250 km (43 mi to 155 mi). C) the surface to an unknown depth. D) the surface down to 2900 km (1800 mi).

5 km to 60 km (3 mi to 37 mi).

Which of the following supports the continental drift concept? A) magnetic field patterns preserved in the rocks B) plant and animal fossil records C) radioactive decay dating of rocks on either side of a spreading center D) All of these support the theory. E) None of these is valid evidence of continental drift.

All of these support the theory

Which of the following is not an example of an age-relationship based on absolute dating? A) The oldest known rocks on Earth are 3.96 billion years old. B) The Vishnu schist at the bottom of the Grand Canyon is 2 billion years old. C) The dinosaurs became extinct 65 million years ago. D) The Coconino formation in the Grand Canyon is older than the Kaibab formation.

D) The Coconino formation in the Grand Canyon is older than the Kaibab formation.

The shape of the earth's surface results from A) gravity. B) the action of wind, water and ice. C) the radioactive decay of atoms. D) all of the above E) gravity and wind, water, and ice only

D) all of the above

Which of the following is exogenic in nature? A) earthquakes B) volcanism C) flows of heat and materials in the mantle D) weathering

D) weathering

Which of the following is incorrect relative to hot spots across Earth's surface? A) Hot spots can occur beneath both oceanic and continental crust. B) They remain relatively fixed in relationship to the migrating plates. C) They are responsible for the formation of the Hawaiian-Emperor Islands chain. D) Hot spot activity is unrelated to the formation of Iceland, which sits atop a sea-floor spreading ridge in the North Atlantic.

Hot spot activity is unrelated to the formation of Iceland, which sits atop a sea-floor spreading ridge in the North Atlantic.

Which of the following is not true of geothermal energy? A) It could be used everywhere. B) It's in use in Iceland, Japan, and California. C) Loss of aquifer pressure and groundwater drawdown can reduce production over time. D) It can be used to produce both heat and electricity.

It could be used everywhere.

Which of the following is not true of the metamorphism process? A) It can be accomplished by heat. B) It can be accomplished by pressure. C) It involves melting of the original rock. D) It can be accomplished by chemical processes.

It involves melting of the original rock.

The boundary between the crust and the rest of the lithospheric upper mantle is a discontinuity known as the A) Gutenberg. B) mantle. C) Moho. D) lithospheric layer.

Moho.

Which of the following is not true? A) The Hawai'ian island chain will subduct in approximately 40 my. B) The newest Hawai'ian island, Lo'ihi, should reach the surface in around 10,000 years. C) Measured from the sea floor to its summit, Mauna Kea is the tallest mountain on Earth. D) The formation of the island of Hawai'i took less than 1 my.

The Hawai'ian island chain will subduct in approximately 40 my.

A guiding principle of Earth science is the principle of uniformitarianismas opposed to catastrophism.

True

Plate boundaries are associated with A) earthquakes. B) volcanoes. C) subduction. D) rifting. E) all of the above

all of the above

The size of sediment transported from an area and subsequently deposited is a function of A) the energy of the transporting agent. B) the relief of the area. C) the energy of the environment. D) all of these E) none of these

all of these

Which of the following is true of divergent plate boundaries? A) Rifting occurs there. B) Tensional forces exist there. C) New ocean crust can be created there. D) all of these E) none of these

all of these

At which of the following locations does subduction occur? A) along collision zones between two continents B) at sea floor spreading zones C) above mantle hot spots D) along collision zones between continental and oceanic plates

along collision zones between continental and oceanic plates

The Sierra Nevada mountain range in California is an example of A) an extrusive igneous formation. B) a lava flow. C) an exposed batholith. D) a volcano.

an exposed batholith.

A rock made of clay particles is most likely to have formed in which of the following environments? A) beach B) desert C) swamp

swamp

Heat energy and new materials are brought to the surface from the interior by the A) tectonic cycle. B) rock cycle. C) hydrologic cycle. D) mineral cycle.

tectonic cycle.

The major rocks of Earth's crust are classified into principal types based on A) element composition. B) mineral composition. C) three specific rock-forming processes, i.e., the manner in which they formed. D) relative and absolute locations.

three specific rock-forming processes, i.e., the manner in which they formed.

Which of the following is true regarding the geologic time scale? A) The bulk of Earth's history has occurred during the Cenozoic era. B) Over 87 percent of Earth's history has elapsed during the more recent Cenozoic, Mesozoic, and Paleozoic eras. C) Both relative and absolute dating methods are used in determining the sequence of the time scale. D) We live in the Tertiary period.

C) Both relative and absolute dating methods are used in determining the sequence of the time scale.

Earth's interior is A) evenly mixed throughout. B) not subject to internal differentiation. C) heated unevenly by the heat of radioactive decay. D) arranged with lighter elements toward the center and heavier elements toward the crust.

C) heated unevenly by the heat of radioactive decay.

Knowledge of Earth's interior is derived from A) direct sampling of the interior using deep-test wells. B) work in Earth's deepest caverns and caves. C) indirect evidence involving the analysis of seismic waves. D) historic and prehistoric records.

C) indirect evidence involving the analysis of seismic waves.

Which of the following is incorrectly matched? A) endogenic- internal processes B) exogenic - external processes C) radioactive decay heat - exogenic energy source D) weathering - exogenic breaking and dissolving the crust

C) radioactive decay heat - exogenic energy source

The ocean floor subducts under continents because A) the ocean floor has a lower density and therefore sinks more easily. B) the ocean floor is made of felsic minerals and is heavier than continental material. C) the ocean floor is made of mafic material and is therefore more dense than continental material. D) the weight of the continents is so great that they push the ocean floor material downward. E) both A and B

C) the ocean floor is made of mafic material and is therefore more dense than continental material.

The ocean floor is a maximum of about 200 million years in age because A) the earth is only 200 million years old. B) the ocean floor is pushed up onto continental material during plate collisions. C) the ocean floor subducts during plate collisions. D) hot spots continuously destroy the ocean floor. E) None of the abovethe ocean floor is 3.96 billion years old.

C) the ocean floor subducts during plate collisions

Which of the following is endogenic in nature? A) weathering B) stream deposition C) volcanism D) glacial erosion

C) volcanism

Uniformitarianism assumes that A) Earth is quite young and is shaped by dramatic events. B) catastrophic episodes have regularly occurred. C) the same physical processes we see today are a key to understanding the processes that have been operating throughout geologic time. D) mountains, plains, and canyons formed by catastrophic events.

C) the same physical processes we see today are a key to understanding the processes that have been

Which of the following can occur when seismic waves encounter a layer in the earth's interior? A) They can be reflected or refracted. B) They can be absorbed. C) Their speed can change. D) All of the above can occur, depending upon the nature of the layer. E) None of the above--seismic waves cannot penetrate below the crust of the earth.

D) All of the above can occur, depending upon the nature of the layer.

Which of the following gives the correct sequence of layers in the earth, from the surface to the center? A) crust, core, lower mantle, aesthenosphere B) aesthenosphere, lower mantle, crust, core C) crust, lower mantle, aesthenosphere, core D) crust, aesthenosphere, lower mantle, core

D) crust, aesthenosphere, lower mantle, core

Earth's magnetic field A) is variable, and it has phased to zero some nine times during the past 4 million years. B) is constant in its intensity. C) remains a mystery as to its cause. D) is principally generated in the inner core.

is variable, and it has phased to zero some nine times during the past 4 million years.

Glaciers that once covered the Hudson Bay area melted 8,000 years ago. As a result of this, the bay is gradually rising. In another 10,000 years or so, it will have risen above sea level and become dry. This process can best be considered an example of A) catastrophism. B) isostasy. C) accretion. D) orogenesis.

isostasy.

Which of the following is matched correctly? A) granite metamorphic B) basalt sedimentary C) magma lava D) sandstone igneous

magma lava

Which of the following is the fuel for continental drift and plate tectonics? A) nuclear fusion B) radioactive decay C) solar energy D) chemical reactions in Earth's core

radioactive decay