Exam #3 Quiz Questions

What is the eruption temperature of rhyolitic lava? 600-800°C 800-1000°C 1000-1200°C 1200-1400°C

600-800 C

Which of the following mountain chains is made up primarily of volcanoes formed at an ocean-continent subduction zone? Andes Himalayas Mariana Islands Appalachians

Andes

What is the largest volcano on Earth? Mauna Loa, Hawaii Mt. Rainier, Washington Mount Unzen, Japan Mont Pinatubo, Philippines

Mauna Loa, Hawaii

Which of the following volcanoes is NOT a composite volcano (stratovolcano)? Mauna Loa, Hawaii Fujiyama, Japan Mt. Rainier, Washington Mt. St. Helens

Mauna Loa, Hawaii

Which of the following volcanic eruptions resulted in the deaths of over 20,000 people? Nevado del Ruiz, Colombia, 1985 Mt. Pinatubo, Philippines, 1991 Mount St. Helens, USA, 1980 Mauna Loa, USA, 2002

Nevado del Ruiz, Colombia, 1985

What is the effect of water on rock melting? Water raises the melting temperature of a rock. Water lowers the melting temperature of a rock. Water does not change the melting temperature of a rock. Water raises or lowers melting temperatures of different rock compositions.

Water lowers the melting temperature of a rock

A nonconformity is a rock unit that is different than the units above or below it. a gap in the geologic record bounded below by metamorphic or igneous rocks and bounded above by sedimentary rocks. a rock unit that does not contain fossils. the intrusive contact between igneous and sedimentary rocks

a gap in the geologic record bounded below by metamorphic or igneous rocks and bounded above by sedimentary rocks.

Which of the following causes a decrease in melting temperature of rocks? decreasing pressure increasing water content more Felsic composition all of the above

all of the above

Which of the following is not involved in classifying igneous rocks? texture group of minerals making up rock chemical composition of the rock All of the above are involved.

all of the above are involved

Which of the following gases is NOT an important constituent of volcanic gas? carbon dioxide sulfur dioxide water vapor hydrogen sulfide all of these are abundant in volcanic gases

all of these are abundant in volcanic gases

Intermediate igneous volcanic rock is: basalt granite gabbro andesite

andesite

Which of the following igneous rocks has the same chemical composition as a diorite? andesite basalt rhyolite gabbro

andesite

Subduction zone volcanoes produce rock of dominantly _____ composition. granitic rhyolitic basaltic andesitic

andesitic

Igneous rocks with crystals too small to be seen without a microscope are: aphanitic phaneritic glassy vesicular

aphantic

The ___________ is the main source of magma for the production of igneous rocks. lithosphere asthenosphere crust core

asthenosphere

Almost the entire ocean floor is comprised of which igneous rock? granite diorite rhyolite basalt

basalt

Which of the following lava types erupts in sheets from fissures to build a lava plateau? andesite basalt rhyolite granitic

basalt

Which of the following type(s) of rock(s) crystallize at the highest temperature? basalt granite hydrothermal veins rhyolite

basalt

Which of the following sequences of volcanic rocks are in the correct order of increasing sialic content? basalt, andesite, rhyolite rhyolite, andesite, basalt basalt, rhyolite, andesite andesite, rhyolite, basalt

basalt, andesite, rhyolite

The three major rock products of erupted lavas are: basalt, granite, and rhyolite. basalt, rhyolite, and andesite. gabbro, andesite, and rhyolite. gabbro, andesite, and granite.

basalt, rhyolite, andesite

Basaltic pillow lavas are a strong indicator of: intrusive crystallization of magma. lava that fountained into the air. basaltic lava that erupted into water. the eruption of already-solid volcanic glass.

basaltic lava that erupted into water

What are the most common igneous rocks found in ophiolites? andesites and diorites basalts and gabbros rhyolites and granites pumice and obsidian

basalts and gabbros

What is the term for a large, steep-walled, basin-shaped depression that forms by the collapse of a magma chamber roof after a violent eruption? diatreme caldera lahar sink hole

caldera

Mantle plumes are thought to originate at the ___ boundary. crust-mantle core-mantle convergent plate divergent

core-mantle

Sediment is deposited as: strong currents accelerate. weak currents accelerate. ice flows. currents slow down.

currents slow down

Which of the following melting processes is important beneath mid-ocean ridges? decompression melting fluid-induced melting both decompression melting and fluid-induced melting neither decompression nor fluid-induced melting

decompression melting

What component of magma is required to cause violent volcanic eruptions? dissolved gases iron calcium aluminum

disolved gases

The process that mobilizes (transports) the particles produced by weathering: deposition diagenesis erosion pickup

erosion

Large igneous provinces like the Columbia River Plateau are formed from the successive eruptions of: pyroclastic flows. andesitic lava. flood basalts. rhyolitic flows.

flood basalts

Magmas in subduction zones are produced primarily by: meteorite impact friction. decompression melting. fluid-induced melting. subduction friction melting.

fluid-induced melting

Which of the following igneous rocks is the most mafic? diorite gabbro granite andesite

gabbro

While basalt is erupting to the ocean floor at mid-ocean ridges, ___________ is crystallizing in underlying magma chambers. andesite granite diorite gabbro

gabbro

The liquid magma that reaches Earth's surface is called: melt intrusive lava glass

lava

Which of the following statements about the viscosity of lavas is true? Lava viscosity increases as the lava increases as it becomes more sialic. Lava viscosity remains the same as as it becomes more sialic. Lava viscosity decreases as it becomes more sialic. Lava viscosity decreases as temperature of magma decreases.

lava viscosity increases as the lava increases as it becomes more sialic

Basaltic lavas form shield volcanoes and flood basalts rather than steep stratovolcanoes because: high silica results in low-viscosity, fluid lava. low silica results in low-viscosity, fluid lava. low silica results in high-viscosity, pasty lava. high silica results in high-viscosity, fluid magma.

low silica results in low-viscosity, fluid lava.

Igneous rocks of Iceland: island arc andesites continental margin andesites mid-ocean ridge basalts continent-continent collision granites

midocean ridge basalts

Which of the following statements is true? Molten rock is less dense than solid rock. Molten rock is denser than solid rock. Molten rock and solid rock have the same density. There is no way to tell which is denser.

molten rock is less dense than solid rock

The dominant rock of Earth's mantle is: peridotite granite basalt andesite

peridotite

Which of the following pairs of intrusive and extrusive igneous rocks do not both have the same chemical composition? diorite and andesite granite and rhyolite peridotite and basalt All of the above pairs have the same chemical compositions.

peridotite and basalt

What mineral is the most abundant in igneous rocks of intermediate composition? quartz pyroxene plagioclase feldspar olivine

plagioclase feldspar

The Mount Pelée eruption of 1902, a mixture of hot air and ash, was a: lava dome. flood basalt. pillow basalt. pyroclastic flow.

pyroclastic flow

The most plentiful minerals in peridotite are: pyroxene and quartz. biotite and plagioclase feldspar. orthoclase and quartz. pyroxene and olivine.

pyroxene and olivine

The process of magmatic differentiation explains how: rocks of varying composition can arise from the same parent magma. magma chambers form in the Earth's crust. water lowers the melting temperature of rock. all igneous rocks end up with the same composition.

rocks of varying composition can arise from the same parent magma

As sediment is transported downstream, the particles tend to become: rounded smaller rounded and smaller Sediment particles are harder than water; nothing happens to them

rounded and smaller

What is the proper term for the huge volcanoes with very gentle slopes? lava domes. flood basalts. ash flow deposits. shield volcanoes.

shield volcanoes

Volcanic domes are associated with ________ magma. sialic mafic basaltic intrusive

sialic

Lava viscosity increases as: silica content increases and lava temperature decreases. silica content decreases and lava temperature decreases. silica content increases and lava temperature increases. silica content decreases and dissolved gases increase.

silica content increases as lava temperature decreases

Felsic, intermediate, and mafic igneous rock all are dominantly made up of ___________ minerals. carbonate sulfide oxide silicate

silicate

During crystallization of a magma, plagioclase feldspar becomes richer in: magnesium calcium sodium iron

sodium

In what tectonic setting would you expect to find intermediate igneous rocks? mid-ocean ridges mantle plumes or "hot spots" subduction zones continental rifts

subduction zone

In 1816, known as "the year without a summer," summer frosts and snowstorms occurred in the Northern Hemisphere as a result of: meteorite impact. dust storms from drought blocking sun. lack of sun's energy. sunlight blocked by debris in atmosphere from eruption of Tambora.

sunlight blocked by debris in atmosphere from eruption of Tambora

Bowen's Reaction Series summarizes: differences between intrusive and extrusive igneous rocks. the partial melting process. the different temperatures at which different silicate minerals form. the different forms of intrusive igneous bodies.

the different temperatures at which different silicate minerals form

Why are lava domes associated with felsic lavas? They are made up of thin felsic fluid flows. The high SiO2 lavas bulge upward but won't flow. Their low SiO2 lavas are explosive. Lava domes are piles of pillow lavas.

the high SiO2 lavas bulge upward but won't flow

Which of the following volcanic features is NOT generally associated with basalt? pahoehoe shield volcanoes volcanic domes cinder cones

volcanic domes

The presence of _________________ in subduction zones lowers the melting temperature and viscosity of resulting magmas over subduction zones. basalt granite uranium water

water

The probable source of Earth's oceans and atmosphere is: the oceans and atmosphere formed when Earth formed. oceans were all water vapor in atmosphere when Earth formed. oceans and atmosphere are entirely from comet collisions with early Earth. water and atmosphere escaped from Earth's interior in volcanic eruptions.

water and atmosphere escaped from Earth's interior in volcanic eruptions