Chapters 4+5 (Mastering Geology)

Rank from oldest to youngest: -Sedimentary country rocks are eroded away. -Magma is injected far below Earth's surface, cutting through sedimentary country rocks. -Humans build a tunnel -Magma crystallizes and a dike is formed.

-Magma is injected far below Earth's surface, cutting through sedimentary country rocks. -Magma crystallizes and a dike is formed. -Sedimentary country rocks are eroded away. -Humans build a tunnel and road through the resistant igneous rocks.

Which of the following features at Yellowstone National Park is evidence for a magma chamber beneath the park? -A thin, recent layer of volcanic ash -Actively flowing lava -Rising (or bowing upward) ground near Yellowstone River -Geysers and hot springs (steam) -Welded tuff

-Rising (or bowing upward) ground near Yellowstone River -Geysers and hot springs (steam) -Welded tuff

What are the three components of magma?

-The liquid portion (mobile ions of the eight most common minerals found in the Earth's crust) called melt -The solid portion which consists of silicate mineral crystals -The gaseous portion called volatiles

What is the best interpretation for how the porphyritic texture of these rocks formed? -The magma cooled rapidly, preserving voids left by gas bubbles. -The magma cooled slowly, forming only large crystals. -The magma cooled quickly, creating only small crystals. -The magma cooled slowly at first, forming large crystals, and then quickly, forming small crystals from the remaining magma. -The magma cooled so rapidly that it produced a solid with no crystalline structure.

-The magma cooled slowly at first, forming large crystals, and then quickly, forming small crystals from the remaining magma.

Which of the following objects has a size similar to that of lapilli? A marble (15 mm) A softball (96 mm) A grain of salt (1 mm) A soccer ball (220 mm)

A marble (15 mm)

How does the viscosity of the magma fed to volcanoes affect nearby life and property? -A volcano that expels magma that is low in viscosity is a greater threat to life and property because it is more explosive, and thus is more difficult or impossible to predict. -A volcano that expels highly viscous magma is a greater threat to life and property because it is more explosive and thus is more difficult or impossible to predict. -A volcano that expels magma that is low in viscosity is a greater threat to life and property because the iron content is more harmful to the environment than silica would be.

A volcano that expels highly viscous magma is a greater threat to life and property because it is more explosive and thus is more difficult or impossible to predict.

How do the crystallization and settling of the earliest formed minerals affect the composition of the remaining magma?

After the earliest formed minerals have settled, the resulting magma will be more felsic than the original magma.

Yellowstone is best described as which of the following? -A currently erupting volcano -An active volcano that has erupted in the last 1 million years -An extinct volcano (it will never erupt again) -An active volcano that has erupted in the last 100 years

An active volcano that has erupted in the last 1 million years

When Eyjafjallajökull erupted in March 2010, ash plumes drifted southeast over Europe and, as a result, the controlled airspaces over many European countries were closed to air traffic, stranding thousands of people worldwide. Why would flying a commercial jet through a cloud of volcanic ash be dangerous? -Ash impairs visibility, clogs engines, and abrades engine parts. -Ash can impede visibility if thick enough. -Abrasion of windows and engine parts from ash. -Engines can be clogged by ash.

Ash impairs visibility, clogs engines, and abrades engine parts.

What kind(s) of lava generate a cinder cone? -Basalt and andesite -Andesite and rhyolite -Basalt -Andesite, basalt, and rhyolite -Andesite

Basalt

What three factors do volcanologists monitor in order to determine whether magma is migrating toward the Earth's surface? -Changes in the patterns of earthquakes caused by the movement of magma, inflation of the volcano, and the gases released from the volcano -Inflation of the volcano, atmospheric temperature near the volcano, and the gases released from the volcano -Changes in the patterns of earthquakes caused by the movement of magma, inflation of the volcano, and changes in the depth of the magma itself

Changes in the patterns of earthquakes caused by the movement of magma, inflation of the volcano, and the gases released from the volcano

Which of the following is the volcanic feature in which magma rises through before it is released at the surface? -Vent -Crater -Lava tube -Conduit -Parasitic cone

Conduit

Which of the following was a stage in the formation of Yellowstone caldera? -Crust bows upward above a magma chamber. -Pyroclastic material erupted from a single vent. -Material exploded from the center of the caldera. -The magma chamber emptied completely during the eruption.

Crust bows upward above a magma chamber.

Which two processes commonly generate magma? -compression melting and dry melting -compression melting and wet melting (the addition of volatiles) -decompression melting and wet melting (the addition of volatiles) -decompression melting and dry melting

Decompression melting and wet melting (the addition of volatiles)

Which of the following choices classifies the three listed rocks by composition and texture? -Diorite is intermediate with a phaneritic texture; rhyolite is felsic with an aphanitic texture; basalt porphyry is felsic with an aphanitic texture. -Diorite is intermediate with a phaneritic texture; rhyolite is felsic with an aphanitic texture; basalt porphyry is mafic with a porphyritic texture. -Diorite is felsic with a phaneritic texture; rhyolite is felsic with an aphanitic texture; basalt porphyry is mafic with a porphyritic texture.

Diorite is intermediate with a phaneritic texture; rhyolite is felsic with an aphanitic texture; basalt porphyry is mafic with a porphyritic texture.

What is the difference between extrusive igneous rocks and intrusive igneous rocks?

Extrusive igneous rocks cool and solidify on the Earth's surface, whereas intrusive igneous rocks cool and solidify beneath the Earth's surface.

You have found a mafic rock with a phaneritic texture. What is a potential rock name? Granite Olivine Diorite Andesite Gabbro

Gabbro

Which materials in Hawaii's lava help to keep it fluid for longer at the surface (as opposed to cooling and solidifying quickly), thus allowing extensive lava flows to develop? Select the two that apply. -water -magnesium -sulfur -iron -silica

Iron Magnesium

Which of the following volcanic materials flows out of a volcanic vent? Volcanic bombs Ash Lava Blocks Lapilli

Lava

Which of the following is true about mafic igneous rocks? Mafic igneous rock examples include diorite and andesite. Mafic igneous rocks are rich in Si, K, and Na. Mafic igneous rocks are rich in Fe, Mg, and Ca. Mafic igneous rocks have a melting temperature around 650° C. Mafic igneous rocks are dominantly composed of muscovite and quartz.

Mafic igneous rocks are rich in Fe, Mg, and Ca.

Which of the following scenarios best describes how the Hawaiian Islands formed in the Pacific Ocean? -Magma generated from a hot spot burned through the overlying plate to create volcanoes. -Crustal material is colliding and being thrust upward from the seafloor, creating mountains. -Tectonic plates are sliding past each other, generating the friction necessary to melt rock to create magma. -New crustal material is being created as two plates comprising the seafloor separate, allowing magma to rise to the surface.

Magma generated from a hot spot burned through the overlying plate to create volcanoes.

Volcanic ash is best described as which of the following? -Microscopic pieces of rock ejected by a volcano -Sand-sized pieces of rock ejected by a volcano -The crust on top of a lava flow -Football-sized pieces of rock that are ejected into the air by an erupting volcano -Remnants from organic material burned by the erupting volcano

Microscopic pieces of rock ejected by a volcano

Name two minerals that are unlikely to coexist in the same igneous rock. Quartz and muscovite Na-plagioclase and amphiboles Pyroxene and olivine Muscovite and pyroxene Quartz and feldspar

Muscovite and pyroxene

Which of the following pieces of evidence for a past volcanic eruption are present at Yellowstone National Park? -Pyroclastic material -A caldera rim -A cone shaped volcano -Human documentation -Lava flows

Pyroclastic material A caldera rim Lava flows

Based on what you learned in this video, what minerals make up rhyolite? Olivine and pyroxenes Quartz, K-feldspar, and plagioclase feldspars, with relatively fewer biotite and amphiboles Amphiboles and pyroxenes Muscovite, biotite, and clays Ca-plagioclase, biotite, and amphiboles

Quartz, K-feldspar, and plagioclase feldspars, with relatively fewer biotite and amphiboles

What is scoria, and how does it differ from pumice? -Scoria is a vesicular ejecta that is produced from mafic magma. Although pumice is also vesicular, it differs from scoria in that pumice is felsic. -Scoria is a vesicular ejecta that is produced from felsic magma. Although pumice is also vesicular, it differs from scoria in that pumice is mafic. -Scoria is an ejecta that is a larger particle size than pumice.

Scoria is a vesicular ejecta that is produced from felsic magma. Although pumice is also vesicular, it differs from scoria in that pumice is mafic.

Match the following pyroclastic materials in order from smallest to largest. Ash Lapilli Volcanic Bombs

Smallest − Ash Neither smallest nor largest − Lapilli Largest − Volcanic bombs

Why is water a necessary component of the melting process in subduction zones? -Water is a liquid, and rock needs to encounter a liquid in order to become a liquid. -The addition of water lowers the melting temperature of rock. -Water changes the density of the rock, allowing the rock to melt. -The addition of water lowers the friction experienced by rising magma.

The addition of water lowers the melting temperature of rock.

The texture of an igneous rock describes -The appearance of a rock based on the size(s), shape(s), and arrangement on the mineral grains it contains. -How a rock feels to the touch. -The appearance of a rock based on how old it is. -The appearance of a rock based on which minerals it contains. -Whether an igneous rock will exhibit cleavage or fracture.

The appearance of a rock based on the size(s), shape(s), and arrangement on the mineral grains it contains.

How does the crystallization of igneous material occur?

The liquid igneous material cools, the ions within slow in their movement, and they pack more closely together. When sufficiently cooled, ions become confined to a crystalline arrangement.

Which of the following is true based off your observation of intrusive igneous rocks on Earth's surface? -They are fragments of country rock that have been incorporated into magma. -These rocks were formed from a lava flow that eventually cooled and solidified. -Intrusive igneous rocks were formed from volcanic eruptions. -These rocks have been exposed by uplift and erosion. -Intrusive igneous rocks are exposed by uplift and deposition.

These rocks have been exposed by uplift and erosion.

What substance makes ion migration easier in the later stages of magma crystallization, which allows abnormally large mineral crystals to form and create pegmatites? -Oxygen -Water -Silica -Iron

Water

Where does the water involved in melting at subduction zones come from? -Water contained within minerals in the overriding plate is released during metamorphism. -Water from the ocean is pulled down by the subducting plate, is absorbed into minerals, and is released during metamorphism. -Water contained within minerals in the subducting plate is released during metamorphism.

Water contained within minerals in the subducting plate is released during metamorphism

How does the composition of a typical lava dome differ from that of a typical fissure eruption? -a lava dome's flow is silica-rich and has a low viscosity, whereas a fissure eruption is basaltic and has a high viscosity. -a lava dome's flow is basaltic and has a high viscosity, whereas a fissure eruption is silica-rich and has a low viscosity. -a lava dome's flow is silica-rich and has a high viscosity, whereas a fissure eruption is basaltic and has a low viscosity.

a lava dome's flow is silica-rich and has a high viscosity, whereas a fissure eruption is basaltic and has a low viscosity.

Which of the following would decrease the viscosity of magma? -an increase in temperature -a decrease in water content -an increase in silica content -a decrease in the slope of the volcanic flank

an increase in temperature

When contrasting lava from composite volcanoes to lava from shield volcanoes,

composite volcanoes most often produce silica-rich lavas with high viscosities, whereas shield volcanoes produce basaltic lavas with low viscosities.

Tsunami

destructive sea wave triggered by powerful explosions or landslides into large bodies of water. − destructive sea wave triggered by powerful explosions or landslides into large bodies of water.

Lahar

fluid mudflow of volcanic debris. − fluid mudflow of volcanic debris.

Igneous rocks of felsic composition have __________ and __________ relative to mafic igneous rocks. greater silica; lower melting temperature darker color; lower melting temperature greater K and Na; higher melting temperature greater Ca; lower melting temperature lighter color; higher melting temperature

greater silica; lower melting temperature

The volcanoes in the Ring of Fire are generally described as -having violent eruptions, as most of these volcanoes are shield volcanoes which eject basaltic lava. -having violent eruptions, as most of these volcanoes are composite cones which eject andesitic lava. -having quiescent eruptions, as most of these volcanoes are composite cones which eject andesitic lava.

having violent eruptions, as most of these volcanoes are composite cones which eject andesitic lava.

Pyroclastic flow

hot, fast-moving body of expanding gas and ash that hugs the flanks of the volcano. − hot, fast-moving body of expanding gas and ash that hugs the flanks of the volcano.

Ash Falls

large volumes of ash precipitating from eruption cloud. − large volumes of ash precipitating from eruption cloud.

What kind of viscosity would flood basalts have?

low viscosity

The partial melting of ____ will yield mafic (basaltic) magma. -andesite -rhyolite -peridotite -diorite -granite

peridotite

Which group of minerals makes up most igneous rocks? -silicates -halides -sulfates -carbonates -oxides

silicates

Volcanic Gases

substances like C O 2, S O 2, C l, and F that can result in climate change and be hazardous to human health. − substances like CO2, SO2, Cl, and F that can result in climate change and be hazardous to human health.

Which of the following has the single most immediate effect on lava's ability to solidify? -gas content -temperature -chemical composition -water content -steepness of slope

temperature

What factors influences the texture of an igneous rock?

the rate at which the rock cools, the amount of silica that is present in the magma from which it forms, and the amount of dissolved gases present in said magma

What is peridotite? -the rock making up the mantle -the mineral that releases water in the mantle -the rock making up the subducting plate -the mineral that absorbs water in the mantle

the rock making up the mantle