Ch. 6, GEOL 100 Exam #3 Review (Chps. 6, 9, 10, and 11)

What type of volcanic eruption is shown in this photograph? IMG: https://www.chegg.com/homework-help/type-volcanic-eruption-shown-photograph-lava-fountainb-coll-chapter-6-problem-1mcq-solution-9780077598570-exc?trackid=4d5faf58472c&strackid=e0f1d2960b5f

A pyroclastic column

Which of the following are differences between an eruption column and pyroclastic flow?

A pyroclastic flow forms when the gas flux cannot support the column.

This figure shows two sections that represent the same age range and contain some of the same fossils. If you compare the two sections, what conclusions do you come to? IMG: https://www.chegg.com/homework-help/figure-shows-two-sections-represent-age-range-contain-fossil-chapter-9-problem-45mcq-solution-9780077598570-exc?trackid=0168b1ab003b&strackid=1285993ba542

B. Some units were deposited in the left section but not in the right one or were eroded away.

This figure shows the main subdivisions of the geologic timescale. Which of these is the Paleozoic? IMG: https://www.chegg.com/homework-help/figure-shows-main-subdivisions-geologic-timescale-paleozoic-chapter-9-problem-34mcq-solution-9780077598570-exc

C

Which of the following sites would most likely have less dangerous volcanoes? A is on an island arc, B is in the Andes, C is near Hawaii, D is along a mid-ocean ridge.

C and D

Where is the oldest layer in this tilted sequence of sedimentary rocks? IMG: https://www.chegg.com/homework-help/oldest-layer-tilted-sequence-sedimentary-rocks-top-hill-cen-chapter-9-problem-6mcq-solution-9780077598570-exc?trackid=bfc93a9172b9&strackid=6b5730915a33

C. The layers on the lower left part of the photograph.

What types of rocks would be common in the volcano in this figure? IMG: https://www.chegg.com/homework-help/types-rocks-would-common-volcano-figure-welded-tuffb-felsic-chapter-6-problem-86mcq-solution-9780077598570-exc?trackid=47e2275cd7fd&strackid=2f613a8cd635

E: All of these choices are correct (welded tuff, felsic and intermediate lava flows, nonwelded tuff, volcanic domes)

From this cross section of the Grand Canyon, what is the youngest rock or structure of the ones listed below? IMG: https://www.chegg.com/homework-help/cross-section-grand-canyon-youngest-rock-structure-ones-list-chapter-9-problem-92mcq-solution-9780077598570-exc?trackid=7230f24c4851&strackid=62d94ed5d7a4

Hurricane fault and faults along the Grand Walsh Cliffs

columnar joints

The igneous rocks shown in this photograph are forming

release of water from the subducting plate

The main cause of melting along subduction zones is the

rhyolite or obsidian

This dark gray igneous rock is glassy and elsewhere contains small vesicles and flow bands. What type of rock is this?

5

Which of the numbered features is a lahar?

This photograph shows three rock layers separated by two disconformities, as exposed in the walls of the Grand Canyon. One disconformity is above the reddish lens of Devonian sedimentary rocks, and the other disconformity is below the reddish lens of Devonian sedimentary rocks. Drag the events so that they are in the correct order, from oldest at the bottom (6) to youngest at the top (1).

1: Erosion that formed the Grand Canyon in which the layers are exposed 2: 3: 4: Deposition of Devonian sedimentary rocks 5: 6:

This photograph shows an angular unconformity in a canyon in Colorado, with Paleozoic sedimentary layers resting on vertical Precambrian layers. Drag the events so that they are in the correct order, from oldest at the bottom (6) to youngest at the top (1). IMG: https://www.chegg.com/homework-help/questions-and-answers/photograph-shows-angular-unconformity-carryon-colorado-paleozoic-sedimentary-layers-restin-q19527504

1: Erosion that formed the canyon in which the layers are exposed. 2: Deposition of Paleozoic sediments above the unconformity. 3: Erosion along the unconformity prior to burial. 4: Uplift of the metamorphic rocks from deeper levels of the crust to the surface, accompanied by erosion of any overlying rocks. 5: Metamorphism and tilting of the metamorphic rocks. 6: Formation of the Precambrian rock prior to metamorphism.

Which of the numbered features is a lahar? IMG: https://www.chegg.com/homework-help/numbered-features-lahar-1b-2c-3d-4e-5-chapter-6-problem-52mcq-solution-9780077598570-exc?trackid=c2861e784472&strackid=7bc8bf8fcb8a

5

a rising plume of hot mantle material

A hot spot is interpreted to have formed from

Which of the following form different layers from season to season and can be used to determine how many years the layers represent?

All of these choices are correct. (tree rings, layers in ice cores, varves)

C

At which of the sites shown in this figure would melting probably be caused by introduction of water into hot rocks?

1

At which points on this graph is the magma under the highest amount of pressure and highest temperature?

Of the following numbered units, which is the oldest? IMG: https://www.chegg.com/homework-help/following-numbered-units-oldest-sedimentary-layer-2-b-grani-chapter-9-problem-75mcq-solution-9780077598570-exc?trackid=2010b816d2d5&strackid=f315028753c0

B. the granite (4)

This photograph shows light-colored granite and darker diorite (both igneous rocks). Which of the following statements is true? IMG: https://www.chegg.com/homework-help/photograph-shows-light-colored-granite-darker-diorite-igneou-chapter-9-problem-10mcq-solution-9780077598570-exc?trackid=17dc9858164c&strackid=3297114c2ba3

C. The granite is younger because it crosscuts the diorite.

the fluid cascade of lava

Comparing these two photographs, which eruption has lower viscosity magma?

in the mantle and in the crust

Continental rifts have a diverse suite of igneous rocks associated with them because melting occurs

This figure shows the main subdivisions of the geologic timescale. Which of these is the Precambrian? IMG: https://www.chegg.com/homework-help/figure-shows-main-subdivisions-geologic-timescale-paleozoic-chapter-9-problem-34mcq-solution-9780077598570-exc

D (bottom one)

What is the main type of eruption that formed the volcano in this photograph? similar-ish IMG: https://www.chegg.com/homework-help/main-type-eruption-formed-volcano-photograph-fluid-lava-flo-chapter-6-problem-34mcq-solution-9780077598570-exc

Fluid lava flows

be explosive

If bubbles cannot escape easily from a magma, the resulting eruption is likely to

From this cross section of the Grand Canyon, what is the boundary between the various Precambrian rocks and the Paleozoic sedimentary units? IMG: https://www.chegg.com/homework-help/cross-section-grand-canyon-boundary-various-precambrian-rock-chapter-9-problem-93mcq-solution-9780077598570-exc

It is an angular unconformity in most places and a nonconformity where it overlies granite.

the more explosive an eruptions it is likely to produce

The higher the gas pressure builds in a magma,

dike

The igneous feature shown in this figure is a

sill

The igneous feature shown in this figure is a

a pyroclastic column.

The type of volcanic eruption shown in this photograph is

For the volcanic eruption in this photograph, complete the two missing parts of the sentence using the type of volcanic feature and type of magma.

This figure shows a lava flow (type of volcanic feature) that forms from eruption of low-viscosity, mafic lava (type of magma). IMG: https://www.chegg.com/homework-help/questions-and-answers/1st-question-2nd-question-wrong-q19399016

For the volcanic eruption in this photograph, complete the three missing parts of the sentence using the viscosity, composition, and resulting rock type.

This figure shows an eruption of high-viscosity (viscosity) magma that probably has a felsic or intermediate (composition) and would form rhyolite or andesite (resulting rock type). IMG:

eruption of a pyroclastic flow that forms a thick and hot deposit

This igneous rock contains flattened pieces of pumice and small crystals of quartz and feldspar. What type of eruption probably formed this rock?

welded tuff

This igneous rock contains flattened pieces of pumice and small crystals of quartz and feldspar. What type of rock is it?

large, less frequent mudflows

What is the main volcanic hazard at site 1?

pahoehoe lava flow

What type of basaltic feature is shown in this photograph?

volcanic bomb

What type of basaltic feature is shown in this photograph?

lava fountain

What type of eruption formed the small volcano in this photograph?

All of these

What type of material likely composes this volcano? -felsic to intermediate lava flows -pyroclastic flows -volcanic mudflows and landslides

basaltic lava flow

What type of volcanic eruption is probably shown in this photograph?

scoria and other vesicular basalt

What types of rocks would be most common in the small volcano in this photograph?

partial melting produces a magma that is more felsic than the source

When melting forms magma

an increase in confining pressure

Which of the following acts to keep a rock solid (instead of melting)?

Viscous magma prevents gas from escaping easily.

Which of the following are ways that viscosity affects gases in magma?

fewer silicate chains in the magma

Which of the following causes magma to be less viscous?

from A to B

Which of the following changes in conditions would cause melting of a solid rock?

destruction by fast-moving lava

Which of the following hazards is probably NOT associated with this volcano?

depth

Which of the following is NOT a factor that affects the viscosity of magma?

all of these

Which of the following is likely to be true about the magma that formed the left volcanic feature compared to the right one in this figure? -the magma has a higher viscosity -the magma has a higher silicate content -the magma is probably more felsic

a volcano that contains andesite and welded tuffs

Which of the following is the best indicator that a volcano might be very dangerous?

Solid asthenosphere rises as plates move apart.

Which of the following is true about igneous processes along oceanic divergent boundaries as shown in this figure?

mid-ocean ridge

Which of the following settings is most likely to have eruptions of basalt?

A and B

Which of the following sites has volcanoes related to subduction? A is on an island arc, B is in the Andes, C is near Hawaii, D is along a mid-ocean ridge.

A and B

Which of the following sites would most likely have composite volcanoes? A is on an island arc, B is in the Andes, C is near Hawaii, D is along a mid-ocean ridge.

C and D

Which of the following sites would most likely have less dangerous volcanoes? A is on an island arc, B is in the Andes, C is near Hawaii, D is along a mid-ocean ridge.

C, D, and E

Which of the magma systems shown is most likely to include felsic or intermediate magmas?

3

Which of the numbered features is a pyroclastic column?

4

Which of the numbered features is a pyroclastic flow?

What type of eruption formed this unit composed of volcanic blocks and volcanic ash? IMG: https://www.chegg.com/homework-help/type-eruption-formed-unit-composed-volcanic-blocks-volcanic-chapter-6-problem-72mcq-solution-9780077598570-exc

a pyroclastic eruption

What type of eruption formed this flow-banded obsidian? similar to this image: https://www.chegg.com/homework-help/type-eruption-formed-flow-banded-obsidian-viscous-lava-flow-chapter-6-problem-70mcq-solution-9780077507237-exc

a viscous lava flow

Isotopes that decay slowly are used to date

ancient rock.

Where are the oldest rocks in the column of sedimentary rocks shown in the diagram? IMG:

at the bottom

Eruptions of scoria cones are commonly associated with

basaltic lava flows and lava fountains.

Volcanic mudflows can be detected remotely by monitoring

characteristic rumbling produced as they rush down valleys.

In geology, determining time equivalency in rocks is called

correlation.

What is a main hazard of this type of volcano? IMG: https://www.chegg.com/homework-help/main-hazard-type-volcano-hot-fragments-thrown-short-distanc-chapter-6-problem-46mcq-solution-9780077598570-exc

destruction by moderately fluid lava flows that can flow far from the volcano

Ash layers from the three most recent caldera-forming eruptions at Yellowstone (2.1, 1.3, and 0.64 million years ago) stretch

from Canada to Mexico

Finding several species of fossils, rather than just one, in the same rock layer is more useful to geologists because

it indicates the sediments must have been deposited at the same time when all the species were present.

Long, thin lava flows are typically produced by

low-viscosity lavas

Mount Pelée, a composite volcano on Martinique, destroyed the town of St. Pierre in 1902, killing about 30,000 people with

pyroclastic flow

Which site on the island is the most dangerous? IMG: https://www.chegg.com/homework-help/site-island-dangerous-location-rock-1b-location-rock-2c-loc-chapter-6-problem-107mcq-solution-9780077598570-exc?trackid=daff1519ba20&strackid=4a7557a4ae68

the location of Rock 1

Which site on the island has evidence for collapse of a volcanic dome? IMG: https://www.chegg.com/homework-help/site-island-evidence-collapse-volcanic-dome-location-rock-1-chapter-6-problem-110mcq-solution-9780077598570-exc

the location of Rock 3

Which numbered feature in this figure is the youngest? IMG: https://www.chegg.com/homework-help/numbered-feature-figure-youngest-upper-volcanic-unit-1-b-li-chapter-9-problem-82mcq-solution-9780077598570-exc?trackid=48f102f2520e&strackid=51699fcba1dd

the upper volcanic unit (1)

How did an oxygen-rich atmosphere develop from a carbon dioxide-rich atmosphere?

through photosynthesis by cyanobacteria

Missing geologic time caused by erosion is called a (an)

unconformity.

Of the following numbered units, which is the youngest? IMG: https://www.chegg.com/homework-help/following-numbered-units-youngest-unit-4b-unit-5c-unit-6d-u-chapter-9-problem-73mcq-solution-9780077598570-exc

unit 9

what type of basaltic feature is shown in this photograph? IMG: https://www.chegg.com/homework-help/type-basaltic-feature-shown-photograph-vesiclesb-volcanic-b-chapter-6-problem-24mcq-solution-9780077507237-exc

vesicles