GOL 105 EXAM 2 CH 4-8

What is a difference between a caldera and a crater? A caldera is a large depression caused by collapse after a large-scale eruption, whereas a crater is a small, steep-sided volcanic depression bored out by an eruptive plume. A caldera is a small, steep-sided volcanic depression created by an eruptive plume, whereas a crater is a large depression caused by collapse after a large-scale eruption. A caldera is a relatively small depression created by the eruptive explosion of a volcano filled with viscous lava, whereas a crater is created by a meteor impact. A caldera is a large depression created by a meteor impact, whereas a crater is a relatively small depression created by the eruptive explosion of a volcano filled with viscous lava.

A caldera is a large depression caused by collapse after a large-scale eruption, whereas a crater is a small, steep-sided volcanic depression bored out by an eruptive plume.

According to Bowen's reaction series for cooling magma, which two minerals are characteristic of lower crystallization temperatures and are absent in basalt and gabbro? biotite and olivine olivine and pyroxene muscovite and quartz quartz and pyroxene

muscovite and quartz

Which of the following is the term for the dangerous, fast-moving, hot, turbulent cloud of volcanic gases and fine-sized pyroclastic particles that precedes an explosive eruption? deflation caldera nuée ardente Vesuvius lahar

nuée ardente

Which of the below mineral(s) is/are likely to form as a phenocryst within porphyritic basalt? quartz muscovite olivine pyroxene biotite both olivine and pyroxene both quartz and muscovite

olivine

Which list of silicate minerals shows the order in which they would weather from least resistant to most resistant? potassium feldspar, quartz, olivine, amphibole olivine, amphibole, potassium feldspar, quartz amphibole, olivine, quartz, potassium feldspar quartz, olivine, potassium feldspar, amphibole

olivine, amphibole, potassium feldspar, quartz

According to Bowen, which sequence of minerals is in the correct order of crystallization from a magma from first to last? pyroxene, olivine, amphibole, and biotite mica olivine, quartz, amphibole, and biotite mica olivine, pyroxene, amphibole, and calcium feldspar olivine, pyroxene, amphibole, and biotite mica

olivine, pyroxene, amphibole, and biotite mica

PHANERITIC

A. means "coarse grained" and is produced when magma cools slowly at depth

ULTRAMAFIC

A. rocks that have substantial amounts of olivine

The process by which magma dislodges pieces of host rock that are melted and incorporated into the magma body is known as __________.

ASSIMILATION

FELSIC

B. contains the rock types granite and rhyolite

PYROCLASTIC

B. produced from debris from an explosive eruption

What type of intrusive feature is this? sill laccolith dike batholith

BATHOLITH

APHANITIC

C. means "fine grained" and is produced when lava cools quickly

BASALTIC

C. substantial dark silicate minerals, calcium-rich plagioclase feldspar

A large depression at the summit of a volcano is called a ________.

CALDERA

__________ are large, volcanic depressions formed by subsidence and collapse of the top of the volcano following explosive eruption.

CALDERAS

What type of volcano has the steepest slopes?

CINDER CONE

What type of volcano is composed mostly of pyroclastic material?

CINDER CONE

What type of volcano is composed of interbedded lavas and pyroclastic deposits?

COMPOSITE CONE

What type of volcano may produce a nuée ardente or lahar?

COMPOSITE CONE

PORPHYRITIC

D. produced when cooling is slow and then rapid

ANDESITIC

D. rocks that have at least 25 percent dark silicate minerals and abundant sodium-rich plagioclase feldspar

What type of intrusive feature is this? sill dike laccolith batholith

DIKE

What type of intrusive feature is this? sill laccolith batholith dike

DIKE

GLASSY

E. produced by rapid cooling and resembles manufactured glass

While doing fieldwork in Hawaii, you get the opportunity to witness firsthand a volcanic eruption. To get to the site of the eruption, you must hike a few miles over lava flows that erupted a few months earlier and are now cooled. You are walking on __________ igneous rocks.

EXTRUSIVE

Why would the presence of earthworms aid soil production?

Earthworms effectively mix organic and inorganic matter.

Select the correct statement regarding soil erosion.

Excessive soil erosion and subsequent sediment deposition can lead to other environmental problems.

When the minerals in an igneous rock cannot be identified, the composition can be estimated based on the percentage of phenocrysts present in the rock. True False

FALSE

Which of the following best describes frost wedging? Frost wedging is a gradual process by which roots from trees wedge rocks apart as they grow larger. Once the rocks break and fall, new roots form in new cracks. Frost wedging is a momentary process by which water freezes inside the pore spaces in rocks and explodes the rocks catastrophically. Frost wedging is a cyclic process by which water in fractures freezes at night, expanding the space between blocks of rock. During daytime, the ice melts, and the process begins again.

Frost wedging is a cyclic process by which water in fractures freezes at night, expanding the space between blocks of rock. During daytime, the ice melts, and the process begins again.

What is the texture of this rock? porphyritic fine-grained glassy andesite

GLASSY

Shield volcanoes are the most common product of ________ volcanism.

HOT SPOT

The geothermal gradient with respect to the distribution of heat in the Earth indicates that as depth increases, temperature __________.

INCREASES

Why is humus an essential component of soil? It is an important source of plant nutrients and neutralizes many soil acids. It provides structure for plant support and improves soil drainage. It is an important source of plant nutrients and improves soil drainage. It is an important source of plant nutrients and enhances the soil's ability to retain water

It is an important source of plant nutrients and enhances the soil's ability to retain water.

What type of intrusive feature is this? laccolith sill dike batholith

LACCOLITH

What is the term for the destructive volcanic mudflow? cinder gust nuée ardente lahar caldera

LAHAR

Igneous rock originates when hot, molten material called __________ cools and crystallizes. skarn firn magma sediment

MAGMA

Which one of the following is NOT a possible product of a volcanic eruption? cinders pyroclastic debris marble ash

MARBLE

The majority of magmas typically contain three distinct parts. Which of the following answers best describes them? Magma typically contains granite, andesite, and basalt. Magma typically contains crystalline mush, a solid component, and a volatile phase. Magma typically contains a liquid component, a solid component, and a gaseous phase. Magma typically contains lava, ash, and pumice.

Magma typically contains a liquid component, a solid component, and a gaseous phase.

What is magmatic differentiation? Magmatic differentiation is the process by which the same magma may produce igneous rocks of different composition. Heavier crystals float on the top of the magma in the magma chamber, producing a layered igneous rock upon complete solidification. Crystal settling may produce different melting conditions for a rock in different plate tectonic scenarios. Magmatic differentiation is the process by which the same igneous rock may produce different magma compositions upon melting.

Magmatic differentiation is the process by which the same magma may produce igneous rocks of different composition.

Which of the following is the correct order of the soil horizons found in a temperate region from top to bottom?

O, A, E, B, C, unweathered parent material

A consistently slowly cooled magma will most likely result in a rock with which one of the following textures?

PHANERITIC

Examine this fine-grained igneous rock which has a granitic (felsic) composition. The rock's name is __________. basalt rhyolite granite diorite

RHYOLITE

Which one of the following greatly affects both the size and arrangement of mineral crystals in an igneous rock? specific gravity of the magma or lava rate of tectonic uplift rate of cooling of the magma or lava composition of the rock surrounding the magma

Rate of cooling of the magma or lava

What is the difference between residual soil and transported soil?

Residual soil is produced from rock, whereas transported soil is produced from unconsolidated sediment.

One mechanism that allows magmatic differentiation is crystal __________.

SETTLING

A magma's viscosity is directly related to its ________ content.

SILICA

What type of intrusive feature is this? batholith dike sill laccolith

SILL

Which of the following statements best describes the soil profile and its relevance to weathering?

Soil-forming processes occur from the top down. This causes vertical variations in soil composition, texture, structure, and color.

Basalt makes up the ocean crust as well as lava flows and volcanic structures on land. True False

TRUE

Igneous rocks are classified based on their texture and mineral composition. True False

TRUE

Igneous rocks that form when lava solidifies are classified as extrusive or volcanic igneous rocks. True False

TRUE

Intrusive igneous bodies are classified according to their shape and orientation with respect to the host rock. True False

TRUE

Why is the rim of the Pacific Ocean called the "Ring of Fire"? Pacific Ocean volcanoes are most associated with fire-type explosions when they erupt. The Pacific basin has the most volcanoes in its interior. The Pacific Ocean is lined by the most continuous belt of volcanoes. The Pacific Ocean is lined by the most active belt of earthquakes.

The Pacific Ocean is lined by the most continuous belt of volcanoes.

Pegmatite is much coarser in grain size compared with most coarse-grained igneous rocks. What is a likely reason for this phaneritic texture? The magma had an excessively long time to cool, allowing crystals to grow very large. The magma was rich in volatiles (such as water), which facilitated fast formation of crystals that are large but little in number. Both of these answers are correct.

The magma was rich in volatiles (such as water), which facilitated fast formation of crystals that are large but little in number.

Which of the following best describes an aphanitic texture? The rock has mineral grains that are glassy. The rock is crystalline, but mineral grains are too small to be seen with the unaided eye. The rock contains broken fragments and is volcanic in origin. The rock is crystalline, but mineral grains are of distinctly different sizes.

The rock is crystalline, but mineral grains are too small to be seen with the unaided eye.

Which of the following is characteristic of pegmatites? They are generally very coarse-grained crystals of feldspar, muscovite, and quartz. They consist of very large grains of quartz, olivine, and pyroxene in relatively large bodies of former sedimentary rock. They often contain diamonds, sapphires, and rubies. Their volumes are very large, comparable in size with granitic batholiths. They often occur with basalt and other mafic igneous rocks.

They are generally very coarse-grained crystals of feldspar, muscovite, and quartz.

Gases such as water vapor, carbon dioxide, and sulfur dioxide are examples of gaseous components of a magma that will vaporize at surface pressures. These types of components are often referred to as __________.

VOLATILES

Which of the following best describes volcanism in the Cascade Range of the northwestern United States? Volcanoes there are related to a mid-ocean ridge system. The volcanism there is related to a large transform fault. Volcanoes there are related to subduction. It is a "hot spot" location.

Volcanoes there are related to subduction.

The addition of __________ causes the melting temperature of peridotite to decrease with depth.

WATER

This rock most likely formed in which of these environments? a submarine lava flow the top portion of a surface lava flow a very thin and shallow intrusive body a large, deep intrusive body

a large, deep intrusive body

This type of magma, with about a 60 percent silica content, tends to form composite cones. basaltic rhyolitic andesitic migmatic

andesitic

Igneous rocks rich in dark silicate minerals with about 50 percent silica are said to have a(n) __________ composition. granitic basaltic rhyolitic fine-grained

basaltic

Magmas that produce __________ rock contain about 50 percent silica and tend to be quite __________. basaltic; viscous basaltic; fluid rhyolitic; viscous rhyolitic; fluid

basaltic; fluid

Which of the following observations might indicate upward migration of magma to the surface? changes in the pattern of volcanic earthquakes decrease in ground temperature sudden decrease in barometric pressure contraction of the near-surface magma chamber

changes in the pattern of volcanic earthquakes

Of the two types of weathering, __________ weathering is accomplished by physical forces that break rock into smaller and smaller pieces without changing the rock's mineral composition.

chemical

__________ cones, such as Sunset Crater, Arizona, tend to have very steep slopes.

cinder

What type of volcano is typically the smallest?

cinder cone

The chemical weathering of silicate minerals frequently produces __________. soluble iron oxides clay minerals feldspars soluble iron oxides and feldspars clay minerals and feldspars

clay minerals

What is the most influential factor controlling soil formation?

climate

What are the significant factors controlling the rate of soil erosion? climate, slope, type of soil type of vegetation, slope, presence of water, aridity slope, type of vegetation, type of soil climate, slope, type of vegetation

climate, slope, type of vegetation

Examine the following close-up of an igneous rock. The rock has a(n) __________ texture. porphyritic fine-grained coarse-grained glassy

coarse-grained

What type of volcano produces the most violent eruptions?

composite cone

What three factors influence the textures of igneous rocks? cooling rate, calcium content, and dissolved gas content cooling rate, silica content, and water cooling rate, silica content, and magma age cooling rate, silica content, and dissolved gas content

cooling rate, silica content, and dissolved gas content

Which term is used to describe chemical weathering processes? thermal expansion decomposition sheeting disintegration

decomposition

What process occurs when hot solid mantle rock ascends in zones of convective upwelling? crystal settling andesite formation decompression melting magmatic cooling

decompression melting

When some rocks weather more rapidly or more slowly than others, it is called:

differential weathering

The formation of caves is associated with this form of chemical weathering. oxidation dissolution hydrolysis exfoliation

dissolution

Which of the following is NOT associated with an external process? glacier landslide earthquake stream weathering

earthquake

Unloading and sheeting are associated with: frost wedging talus slopes thermal expansion exfoliation domes

exfoliation domes

Breaking a rock into smaller pieces decreases the rate of chemical weathering. True False

false

An igneous rock with less than 15 percent dark minerals would have a(n) __________ composition. detrital (lithic) basaltic (mafic) andesitic (intermediate) granitic (felsic)

granitic (felsic)

Igneous rocks that form from the last minerals to crystallize from magma will have a(n) __________ composition consisting of quartz, potassium feldspar, and sodium-rich plagioclase feldspar. andesitic (intermediate) basaltic (mafic) granitic (felsic) mafic (felsic)

granitic (felsic)

In a rock with a porphyritic texture, the smaller crystals are referred to as __________. phenocrysts erratics orthoblasts groundmass

groundmass

When water freezes, its volume: increases decreases remains unchanged

increases

When a rock undergoes __________, such as frost wedging, it is broken into smaller and smaller pieces. oxidation mechanical weathering lithification chemical weathering dissolution

mech. weathering

In which of the following climates is chemical weathering most effective? snowy areas with warm temperatures wet areas with low temperatures moist areas with warm temperatures dry areas with low temperatures

moist areas with warm temperatures

Iron oxide is the product of which one of these weathering processes? :

oxidation

Which type of soil is rich in iron aluminum oxides, is heavily leached, and is considered poor for agricultural use?

oxisol

Which of these rocks is composed almost entirely of ferromagnesian minerals? basalt rhyolite peridotite granite

peridotite

In a rock with a porphyritic texture, the large crystals are referred to as __________. erratics orthoblasts groundmass phenocrysts

phenocrysts

Which "tough" mineral is most likely to survive extensive chemical weathering and form sand grains on beaches or dunes?

quartz

The layer of rock and mineral fragments produced by weathering is referred to as __________. humus subsoil zone of leaching soil regolith

regolith

This type of magma, with a silica content of about 70 percent, has the greatest tendency to form pyroclastics. migmatic rhyolitic basaltic andesitic

rhyolitic

Which of the following is the correct order of decreasing magma viscosity due to decreasing silica content? basaltic, rhyolitic, andesitic basaltic, andesitic, rhyolitic rhyolitic, andesitic, basaltic andesitic, rhyolitic, basaltic

rhyolitic, andesitic, basaltic

Which of the following best describes why silica content is a good indicator of igneous rock/magma composition? rocks that are high in silica contain lesser amounts of iron, magnesium, and calcium magmas that are high in silica are viscous and erupt at temperatures in excess of 1100 degrees rocks that have low silica content melt at lower temperatures than rocks that have high silica content rocks that exhibit high silica content also exhibit high concentrations of magnesium and calcium

rocks that are high in silica contain lesser amounts of iron, magnesium, and calcium

Which type of volcano is composed almost exclusively of pyroclastic debris? scoria cone ocean ridge stratovolcano shield

scoria cone

A volcano that takes the shape of a broad, domed structure is called a __________ volcano. shield composite cinder

shiel

What type of volcano is composed mostly of basaltic lava flows?

shield volcano

What type of volcano is typically the largest?

shield volcano

Which type of volcano would most likely be composed primarily of basaltic lava flows? cinder cone composite cone stratovolcano shield volcano

shield volcano

Which one of the following is NOT a product of the complete chemical weathering of the mineral potassium feldspar? kaolinite (clay) potassium ion (in solution) bicarbonate ion (in solution) silica sodium hydroxide End of Question 7

sodium hydroxide

Which one of the following is NOT a product of the chemical weathering of granite?

sulfur dioxide

If granite and basalt were exposed in an area with a hot and humid climate: the basalt would weather most rapidly there is no way of knowing which rock type would weather most rapidly both rocks would weather at the same rate the granite would weather most rapidly

the basalt would weather most rapidly

Two headstones, one marble and the other granite, were erected in the same New England cemetery 150 years ago. Which headstone is likely to have the least weathered, easiest to read inscription? :

the granite headstone

The process of weathering is best described as _______. the physical removal of materials by water, wind, or ice the physical breakdown and chemical alteration of rocks at or near Earth's surface the transfer of rock and soil downslope under the influence of gravity the persistence of resistant materials at Earth's surface

the physical breakdown and chemical alteration of rocks at or near Earth's surface

Rocks that contain voids left by gases that escape as lava solidifies are said to exhibit a(n) __________ texture. coarse-grained porphyritic fine-grained vesicular

vesicular

Which of the following types of tephra is ejected as incandescent lava? volcanic blocks lapilli welded tuff volcanic bombs

volcanic bombs

Which one of the following is NOT a primary factor of magma that directly determines the nature of a volcanic eruption? amount of dissolved gases composition temperature volume

volume

What is by far the most important agent of chemical weathering, and why? the Sun because it drives all external processes on Earth exfoliation because new cracks give chemical reactions the chance to operate soil because moisture in soil is the carrier of acids and drives chemical weathering water because it is a good solvent and carrier of acids

water because it is a good solvent and carrier of acids

The most abundant gases expelled during a volcanic eruption are ________. water and sulfur dioxide water vapor and carbon dioxide carbon dioxide and sulfur dioxide water and nitrogen

water vapor and carbon dioxide

At what point does soil become sediment? when soil is on the bottom of a slope when soil makes it to the ocean or a lake when soil is produced and water is expelled when soil makes it down slope and enters into a stream

when soil makes it down slope and enters into a stream