Chapter 6 Quiz

docx

School

Miami Dade College, Kendall *

*We aren’t endorsed by this school

Course

100

Subject

Geology

Date

Feb 20, 2024

Type

docx

Pages

Uploaded by KidWildcat1954

100 Question 1 The viscosities of magmas increase with increasing percentages of silica. True False Question 2 Powerful, explosive, volcanic eruptions can result in climatic cooling for millions of years following the eruption. True False Question 3 Which of the following is not considered pyroclastic debris? pahoehoe bombs cinders ash Question 4 Which of the following statements best describes the big Hawaiian volcanoes? They are situated in the interior of a large, Pacific plate above a hot spot deep in the mantle. They lie directly above a transform plate boundary that cuts deeply into the mantle. They lie directly above an active subduction zone where the Pacific plate is sinking into the mantle. They lie along the crest of the East Pacific Rise, a mid-ocean ridge or spreading center. Question 5 Magmas are the product of melting in the deep part of the earth that forms a layer of molten material called the asthenosphere. True False

100 Question 6 Where are the most active volcanoes in the world? Mexico Italy Hawaii Washington State, in the United States Question 7 A rock outcrop exposes a layer of obsidian overlain by volcanic ash and a layer with fragments of lapilli. What rock composition and eruptive type fits this description? rhyolite erupted in violent pyroclastic eruptions andesite and basalt erupted from a stratovolcano basalt erupted from a cinder cone basalt flows and interbedded andesite deposited on a shield volcano Question 8 Which of the following best describes the bedrock in the Sierra Nevada Mountains in California? gabbro; plutoliths granite; batholiths basalt; dikes andesite; laccoliths Question 9 Which statement about the May, 1980, eruption of Mount St. Helens is false? Plumes of ash rose high into the atmosphere during the major eruptive events. During the eruptive period, the mountain peak was substantially built up by new lava flows and pyroclastic debris. Mudflows accompanied the major eruptive events. The most powerful explosive event was preceded by a massive landslide.

100 Question 10 A basaltic volcano is likely to produce an explosive column that would endanger flying aircraft. True False Question 11 Mount Pelee on the Island of Martinique erupted in the early 20 th century. Why is this eruption famous? It was a small cinder cone on an island that erupted in a sugar cane field. It produced a major lateral blast that leveled a city, killing many people. It was the first caldera forming eruption observed by modern scientists. The volcano produced a pyroclastic flow that swept down the mountain, killing thousands of people. Question 12 The higher the viscosity of a magma, the lower the potential for explosive eruptions. True False Question 13 Which type of basaltic lava flow has a fairly smooth, unfragmented, ropy surface? pahoehoe aa pegmatitic scoria

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

100 Question 14 As magma approaches the surface, water contributes to the explosive potential of the eruption because ________. water has a large heat capacity, which allow it to keep the magma hot enough to explode water dissolved in magma flashes to steam as pressure decreases, and the volume increase leads to an explosive potential water has a lower density in its solid phase than its liquid phase which makes it explode when pressure decreases water dissociates to hydrogen and oxygen at high temperatures but reacts violently at decreasing pressures to produce explosive eruptions Question 15 Paricutin is an example of a ________. composite volcano cinder cone shield volcano lava dome Question 16 Many magmas are generated when solid rocks are carried to higher levels in the earth by flow and partially melted by decompression melting. True False Question 17 When magma rises toward the surface, pressure decreases can lead to release of dissolved gases in a magma with a volume increase that can produce an explosion. True False

100 Question 18 Which of the following is not a significant volcanic hazard? injury or death by inhalation of air heavily laden with volcanic ash a tsunami generated by a massive submarine volcanic eruption being caught in a river valley and being overcome by a volcanic mudflow/lahar being overrun by a fast moving basaltic lava flow Question 19 What type of volcanic material is indicative of eruption under water? AA flows Pyroclastic flows Pillow lavas Pahoehoe flows Lava aprons Question 20 Volcanos have no significant impact on weather and climate. True False Question 21 The rock pumice often floats yet the density of the rock is greater than water. Why does it float? Pumice is a pyroclastic rock derived from rhyolite glass, and rhyolite glass has a lower density than water. Pumice is a pyroclastic rock comprised largely of open voids formed by gases released when the magma solidified as froth-like material. Pumice is a rock made of rhyolite glass that erupts into water, which traps water in voids and makes the material less dense than water. Pumice is another name for dacite, a low-density rock that floats in water.

100 Question 22 Volcano A erupts rocks with SiO 2 content ranging from 49% to 52% whereas volcano B, 100km away, erupts materials with SiO 2 content of 62-68%. Which statement best characterizes these two volcanos? Volcano A is likely to be a supervolcano with violent eruptions, whereas volcano B is probably a shield volcano with quiescent eruptions. Both volcanos are violent, explosive volcanos that spread ash continent wide. Both volcanos are shield type volcanos that are characterized by quiescent eruptions. Volcano A is probably a shield volcano with typically quiescent eruptions, whereas Volcano B is likely a stratovolcano characterized by violent, explosive eruptions. Question 23 In what plate tectonic setting are magmas generated predominantly by fluids fluxing the melting process by decreasing melting temperature? spreading ridges hot spots transform faults convergent plate margins Question 24 Which of the following is a tabular intrusive body with subparallel intrusive contacts? stock columnar joints dike laccolith Question 25 A ________ is the largest discordant body of intrusive, igneous rock. pluton batholith lopolith laccolith

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

Chapter 6 Quiz

Related Documents