Geology Chapter 3 - 4

25 July 2022
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question
What are the two most abundant elements in Earth's crust?
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Oxygen and silicon
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What minerals make up half of Earth's crust?
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feldspars
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What is an accurate description of the silicon-oxygen tetrahedron?
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The silicon-oxygen tetrahedron is a four-sided figure with a silicon atom in the middle bonded to four neighboring oxygen atoms.
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The micas (biotite and muscovite) exhibit what type of silicate structure?
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sheet
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__________ SiO4 4- tetrahedra join with __________ ions to produce the mineral olivine in the rock peridotite.
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Independent; Mg2+ and Fe2+
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Which of the following is considered a ferromagnesian silicate? CHOOSE ALL THAT APPLY.
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Garnet; Biotite
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What is the most effective way to differentiate potassium feldspar from plagioclase feldspar?
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e. Some cleavage planes of plagioclase feldspars have striations, whereas no potassium feldspars have striations.
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Which nonsilicate mineral has carbonate as a negatively charged complex ion?
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calcite
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What are the two most common carbonate minerals?
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calcite and dolomite
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What are the economic uses of three common nonsilicate minerals?
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Halite is used for common salt, gypsum is used in plaster, and graphite is used as pencil lead.
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What is the mineral name for table salt?
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Halite
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s molten rock that is below the Earth's surface and retains most of its volcanic gases.
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magma
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What three components make up most magmas
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liquid portion, solid portion, gaseous portion
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What is a volatile?
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Gases dissolved in a magma
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When magma forms, it rises up through the crust. Why does magma rise?
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it is less dense
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The granitic igneous rocks that make up the Sierra Nevada Mountains in California and Nevada are ________.
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intrusive
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mafic
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50% silica content
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felsic
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70% silica content
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intermediate
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60% silica content
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Which mineral group makes up most igneous rocks?
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silicates
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Which two minerals define a felsic composition?
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Quartz and Potassium Feldspar
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halides
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Cl−, F−, Br−
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Sulfides
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S-
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sulfates
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SO42-
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carbonates
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CO32-
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silicates
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SiO24-
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Only eight elements make up the vast majority of rock-forming minerals. Which of the following elements is not one of the eight?
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potassium
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The ________ are the mineral class that accounts for more than 90 percent of the Earth's crust.
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silicates
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Which of the following pairs of elements are the most abundant in the continental crust?
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silicon and oxygen
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What are the eight most common elements found in the Earth's crust, listed from most common to least common (by percent)?
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oxygen, silicon, aluminum, iron, calcium, sodium, potassium, magnesium
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Olivine −
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Independent tetrahedra
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Pyroxene −
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Single chain
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Amphibole −
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Double chain
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Muscovite −
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Sheet
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Quartz −
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Network
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A(n) ________ is a silicate structure where no silica tetrahedra share any oxygen ions.
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independent
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Silica tetrahedra are able to link into long chains that share oxygen ions through the process of ________.
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polymerization
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Where do ultramafic rocks form?
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upper mantle
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Based on the diagram shown in the video, name two minerals that are unlikely to coexist in the same igneous rock.
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Muscovite and Pyroxene
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Igneous rocks of felsic composition have ______ and _____ relative to mafic igneous rocks.
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Greater silica, Lower melting temperature
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Which of the following is true about mafic igneous rocks?
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Mafic igneous rocks are rich in Fe, Mg, and Ca.
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You have found a mafic rock with a phaneritic texture. What is a potential rock name?
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gabbro
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Based on what you learned in this video, what minerals make up rhyolite?
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Quartz, K-feldspar, and plagioclase feldspars, with relatively fewer biotite and amphiboles
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Fill in the blanks using the choices below: ____ are minerals typically found in igneous rocks that have a high silica content, whereas ____ are minerals that are typically found in igneous rocks with a low silica content.
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Plagioclase feldspar and quartz; pyroxene and olivine
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Slow cooling produces ________ crystals, whereas fast cooling produces ________ crystals.
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Slow cooling produces large crystals, whereas fast cooling produces small crystals.
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What is the geologic definition of texture?
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Size, shape, and arrangement of mineral grains in the sample
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What creates the small holes found in a vesicular texture?
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Volatiles
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Which of the following best describes a pegmatitic texture?
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Large crystals that form in a fluid-rich environment late in crystallization
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An igneous rock with a ______ texture solidified deep within Earth.
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phaneritic
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What factors influences the texture of an igneous rock?
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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
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granite
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Intrusive igneous rocks
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diorite
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Intrusive igneous rocks
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rhyolite
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Extrusive igneous rocks
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Andesite porphyry.
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Porphyritic igneous rocks
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What is one way a glassy texture forms?
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Lava cools rapidly.
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Which of the following describes a texture containing bubble-shaped cavities?
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Vesicular
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Which of the following textures describes an igneous rock with anomalously large crystals?
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pegmatitic
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What does an igneous rock with a pyroclastic texture tell a geologist?
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The rock was likely formed by a violent volcanic eruption.
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Which of the following textures indicates two stages of cooling and crystallization?
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porphyritic
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How are igneous rocks formed?
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Igneous rocks are formed by the cooling and crystallization of molten rock.
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Intrusive and extrusive igneous rocks are classified based on what criteria?
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How quickly the molten rock cools and crystallizes, and where this occurs with respect to Earth's surface.
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What is required to generate an igneous rock with a fine-grained texture?
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A fine-grained texture is the product of rapid cooling and crystallization of lava.
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A phaneritic texture is characteristic of a(n) __________ igneous rock that cooled __________.
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intrusive below the surface
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What does it mean if an igneous rock has an aphanitic texture?
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The igneous rock exhibits mineral crystals too small to see with the naked eye.