Geology

Here are the correct answers to each question from your quiz: 1. felsic; 2. Pegmatite; 3. breakdown of water-bearing minerals, such as micas, through metamorphism; 4. welded tuff; 5. olivine; 6. Mafic; 7. Peridotite; 8. vesicles; 9. volcanic rocks only have enough time to grow small crystals while coarser-grained rocks cool more slowly at greater depths.; 10. Plagioclase; 11. crystal size; 12. True; 13. olivine; 14. Felsic and Intermediate magma; 15. volcanic rocks.

Question 1

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Igneous rocks with a ________ composition are formed by silacate minerals that form at the lowest temperatures, such as quartz, K-feldspar, and muscovite.

felsic

intermediate

mafic

ultramafic

Question 2

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Very coarse igneous rocks, which contain large crystals centimeters to meters in length, are known as ________________. 

Obsidian

Pumice

Pegmatite

Granite

Question 3

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What is the source of the water in a subduction zone?

breakdown of water-bearing minerals, such as micas, through metamorphism.

Rain being intercepted by volcanoes

Absorption of water from oceanic muds

Water vapor from deep within the mantle

Question 4

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_______________often times forms within a thick pyroclastic flows.

welded tuff

porphyry

intrusive phanerites

lavas

Question 5

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Which of the following minerals  in Bowen's reaction series forms at the highest temeratures?

biotite

quartz

olivine

muscovite

Question 6

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Which igneous material has high contents of magnesium(Mg) and iron (Fe), generally accompanied by a decreased amount of silica (SiO₂)

Felsic

Mafic

Granitic

Intermediate

Question 7

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________ contains more magnesium-rich and iron-rich minerals, especially green olivine and dark pyroxene.

Peridotite

Rhyolite

Andesite

Granite

Question 8

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A ________ are small holes found in a volcanic rock, respresenting gas bubbles in a magma that were trapped when the lava solidified

porphyrocryst

vesicles

phenocryst

xenocryst

Question 9

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Why do volcanic rocks have smaller minerals as compared to coarse-grained rocks? 

volcanic lavas are well-insulated by the surrounding rock

intrusive magma flows onto the Earth's surface and cools very slowly to form fine-grained volcanic rocks.

volcanic rocks only have enough time to grow small crystals while coarser-grained rocks cool more slowly at greater depths. 

Coarser-grained rocks cool very quickly while volcanic rocks cool more slowly at greater depths. 

Question 10

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Which of the following minerals is the most common minerals in gabbro?

Plagioclase

Microcline

Orthoclase

Potassium Feldspar

Question 11

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All of the following causes a rock to melt except for ________.

crystal size

pressure

heat

water

Question 12

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New oceanic crust, which forms at mid-ocean ridges, is mafic.

True

False

Question 13

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Consider the Bowen's reaction series. Which mineral would you expect to see as a phenocryst (fully-formed crystal) in a porphyritic mafic rock?

olivine

quartz

orthoclase

sodium-rich plagioclase

Question 14

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The products of partial melting in an overriding continent above a subduction zone.  

Felsic and Intermediate magma

Ultramafic and mafic magma

Mafic and basic magma

flood basalts

Question 15

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Pumice and obsidian are both....

basaltic in composition

volcanic  rocks

ultramafic in composition

phaneritic in texture

Question 1

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Name two flood basalts that forms in association with deep mantle hot spots.

Vesuvius and the other volcanoes of Italy

Mt. St. Helens and other volcanoes of the Cascade Mountains

the very young cinder cones scattered across the southwestern United States

The Columbia Plateau and Yellowstone National Park

Question 2

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Which of the following is associated with a explosive volcanism?

lava flows from a large cinder cone complex

fissure eruptions feeding lava to flood basalt accumulations

lava flows from a large shield volcano on an oceanic island

composite volcanoes

Question 3

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The largest concentration of composite volcanoes is along __________

the area surrounding the Red Sea

European Russia and Siberian traps 

the coastal plain of western Africa

the Pacific Ring of Fire 

Question 4

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________ magma has a relatively low viscosity and erupts in a fluid lava flow.

Basaltic

Granitic

Pegmatitic

Andesitic

Question 5

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Composite volcanoes consist mostly of ......

intermediate

ultramafic

basaltic

rhyolitic

Question 6

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The eruption of Mount St. Helens was ________.

the first large shield volcano eruption to occur on television

the first large composite volcano eruption to occur on television

a typical basaltic cinder cone

only a small, welded tuff cone

Question 7

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The Columbia Plateau in Washington and Oregon is ________.

a thick stack of welded-tuff layers 

a field of large stratovolcanoes

a flood basalt 

a caldera filled with rhyolite lava flows

Question 8

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Which of the following is true regarding the viscosity of lava types.

Felsic magma is less viscous than basaltic (mafic) magma

Felsic and basaltic (mafic) magma have roughly the same viscosity

Variations in viscosity of Felsic or basaltic (mafic) magma are too great to make a comparison between the two

Felsic magma is more viscous than basaltic (mafic) magma

Question 9

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Which type of lava or lava flow has a smooth upper surface or folds that form a "ropy" texture?

pegmatitic

pahoehoe

aa

scoria

Question 10

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____________ volcanism is associated with mid-oceanic ridge system.

fissure eruptions; flood andesite fields

ocean-bottom; basaltic lava eruptions

explosive; composite cones

explosive; rhyolitic, pyroclastic flows

Question 11

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The volcanoes concentrated around the rim of the ___________ ocean form above subduction zones.

Indian

Arctic 

Atlantic

Pacific

Question 12

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Which of the following statements is true regarding the big Hawaiian volcanoes?

lie directly above a transform plate boundary that cuts deeply into the mantle

they have a broad, shield-shaped form and fairly gentle slopes when compared to other volcanoes.

they are known for killing tens of thousands of people during their eruptions

they are explosive, steep-sided stratovolcanoes 

Question 13

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The Cascade region exists because they are...

related to a mid-oceanic ridge system

related to a mantle hot spot

related to plate subduction

related to deep, transform faults

Question 14

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_______ volcanoes are the largest volcanoes on Earth, which erupt mostly low-viscosity basaltic lava and so are dominated by relatively non-explosive outpourings of lava from fissures and vents. 

shield

composite

stratospheric

cinder cone

Question 15

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Volcanic bombs are ________.

large rock fragments representing a large blob of magma  ejected during an explosive volcanic eruption

blocks of volcanic rock ejected from an erupting volcanic crater

ash particles that join together in the eruptive plume and fall as cobble-sized objects

 laser-guided granite blocks launched from a supersonic jet

Question 16

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The large caldera-forming eruptions in the Yellowstone region are ________.

related to hot spot volcanism

related to a divergent plate boundary

related to plate subduction

related to a transform plate boundary

Quiz Score: 0.96 out of 0.96