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61 Cards in this Set
- Front
- Back
What igneous rock is the most mafic? |
Gabbro |
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What mineral is the most abundant in igneous rocks of intermediate composition? |
Plagioclase feldspar |
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What igneous rock has the same chemical composition as a diorite? |
Andesite |
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What pair of intrusive and extrusive igneous rocks do not both have the same chemical composition? |
Peridotite and basalt |
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What is the effect of water on rock melting? |
Water lowers the melting temperature of a rock |
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Which is less dense, molten or solid rock?
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Molten rock is less dense than solid rock |
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During crystallization of a magma, plagioclase feldspar becomes richer in: |
Sodium |
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The process of magmatic differentiation explains how: |
Rocks of varying composition can arise from the same parent magma |
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What type(s) of rock(s) crystallize at the highest temperature? |
Basalt |
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What are the most common igneous rocks found in ophiolites? |
Basalts and gabbros |
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What melting processes is important beneath mid-ocean ridges? |
Decompression melting |
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In what tectonic setting would you expect to find intermediate igneous rocks? |
Subduction zones |
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What are not involved in classifying igneous rocks? |
-texture -group of minerals making up rock -chemical composition of the rock |
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Igneous rocks with crystals too small to be seen without a microscope are: |
Aphanitic |
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Intermediate igneous volcanic rock is: |
Andesite |
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Felsic, intermediate, and mafic igneous rock all are dominantly made up of ___________ minerals. |
Silicate |
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Almost the entire ocean floor is comprised of which igneous rock? |
Basalt |
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The dominant rock of Earth’s mantle is: |
Peridotite |
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The most plentiful minerals in peridotite are: |
Pyroxene and olivine |
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What causes a decrease in melting temperature of rocks? |
-decreasing pressure -increasing water content -more Felsic composition |
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Bowen’s Reaction Series summarizes: |
The different temperatures at which different silicate minerals form |
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The presence of _________________ in subduction zones lowers the melting temperature and viscosity of resulting magmas over subduction zones. |
Water |
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While basalt is erupting to the ocean floor at mid-ocean ridges, ___________ is crystallizing in underlying magma chambers. |
Gabbro |
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Igneous rocks of Iceland: |
Mid-ocean ridge basalts |
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What about the viscosity of lavas is true? |
Lava viscosity increases as the lava increases as it becomes more sialic |
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What is the eruption temperature of rhyolitic lava? |
600-800 *C |
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What volcanic features is NOT generally associated with basalt? |
Volcanic domes |
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Which of the following sequences of volcanic rocks are in the correct order of increasing sialic content? |
Basalt, andesite, rhyolite |
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What volcano is NOT a composite volcano (stratovolcano)? |
Mauna Loa, Hawaii |
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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? |
Caldera |
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What lava type erupts in sheets from fissures to build a lava plateau? |
Basalt |
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Volcanic domes are associated with ________ magma. |
Sialic |
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What gases are NOT an important constituent of volcanic gas? |
-carbon dioxide -sulfur dioxide -water vapor -hydrogen sulfide |
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Which mountain chains are made up primarily of volcanoes formed at an ocean-continent subduction zone? |
Andes |
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Large igneous provinces like the Columbia River Plateau are formed from the successive eruptions of: |
Flood basalt |
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Which volcanic eruptions resulted in the deaths of over 20,000 people? |
Nevado del Ruiz, Colombia, 1985 |
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Mantle plumes are thought to originate at the ___ boundary. |
Core-mantle |
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The ___________ is the main source of magma for the production of igneous rocks. |
Asthenosphere
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The liquid magma that reaches Earth’s surface is called: |
Lava |
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What component of magma is required to cause violent volcanic eruptions? |
Dissolved gases |
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Lava viscosity increases as: |
Silica content increases and lava temperature decreases |
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The three major rock products of erupted lavas are: |
Basalt, rhyolite, and andesite |
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Basaltic lavas form shield volcanoes and flood basalts rather than steep stratovolcanoes because: |
Low silica results in low-viscosity, fluid lava |
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Basaltic pillow lavas are a strong indicator of: |
Basaltic lava that erupted into water |
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Why are lava domes associated with felsic lavas? |
The high SiO2 lavas bulge upward but don't flow |
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The Mount Pelée eruption of 1902, a mixture of hot air and ash, was a: |
Pyroclastic flow |
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What is the largest volcano on Earth? |
Mauna Loa, Hawaii |
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What is the proper term for the huge volcanoes with very gentle slopes? |
Shield volcanoes |
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The probable source of Earth's oceans and atmosphere is: |
Water and atmosphere escaped from Earth's interior in volcanic eruptions |
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In 1816, known as “the year without a summer,” summer frosts and snowstorms occurred in the Northern Hemisphere as a result of: |
Sunlight blocked by debris in atmostphere from eruption of Tambora |
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Magmas in subduction zones are produced primarily by: |
Fluid-induced melting |
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Subduction zone volcanoes produce rock of dominantly _____ composition |
Andesitic |
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Weathering process is subdivided into: |
Physical and chemical |
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As sediment is transported downstream, the particles tend to become: |
Rounded and smaller |
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Which sedimentary rocks has the largest particle sizes? |
Conglomerate |
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Sediment is deposited as: |
Currents slow down |
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The process that mobilizes the particles produced by weathering: |
Erosion |
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The process that breaks rocks into smaller pieces that are not changed in composition: |
Physical weathering |
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Sedimentary rocks are a primary source of information about: |
-past climates -evolution of life on Earth -energy resources |
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Consider three undeformed horizontal beds of sedimentary rocks. What layer is the oldest? |
Lower |
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A nonconformity is: |
A gap in the geologic record bounded below by metamorphic or igneous rocks and bounded above by sedimentary rocks |