Geology Quiz Answers Chapter 5

Chapter 5: ● Rock that has formed from cooling magma or lava is ______ rock. ○ Igneous ● Igneous rocks are broadly divided into two categories: those that have _____ that can be seen with the unaided eye and those that require some type of magnification. ○ Crystals or minerals ● Lava is molten rock that cools ______. ○ On the surface ● Igneous rocks vary in their chemical composition and subsequently in their ______. ○ Mineral content ● Select the characteristics listed below that could be used to classify the igneous rocks in the image. ○ The aphanitic or phaneritic nature of the rocks ○ The mineral content ● Rock that has solidified from magma is an ______rock. ○ Igneous, intrusive, or plutonic ● A hand lens could be used to examine a ________-grained igneous rock, while a ________ would be needed to examine the crystals in a fine-grained igneous rock. ○ Coarse ○ Microscope ● From the list below, select the terms that are associated with igneous rocks that have crystals observable by the unaided eye. ○ Phaneritic ○ Pegmatite ○ Porphyritic ● Match the type of igneous rock on the left with its definition on the right. ○ Felsic ■ Abundant quartz and feldspar; light colored ○ Mafic/ultramafic ■ Abundant magnesium and iron; dark colored ○ Intermediate ■ Mineral content in between; color moderate ● Igneous rocks contain different minerals so their _______ composition varies. ○ Chemical or elemental ● The primary chemical component of igneous rocks is ______, which ranges between 44% and 77%. ○ Silica ● These igneous rocks can be classified using their color which reflects the types of ______ within the rocks, and using their texture. ○ Minerals ● Which of the following produced significant amounts of heat during the early formation of Earth, which started approximately 4.5 billion years ago? ○ Impacts of meteors and asteroids ○ Collision and compression of materials by gravity ○ Sinking of the molten iron and nickel into Earth's interior ● To study an igneous rock with a phaneritic texture, a geologist would likely use ______. ○ A hand lens ● The temperature increase with depth is called the geothermal ○ Gradient ● Match the name of the igneous rock on the left with its compositional term on the right. ○ Granite ■ Felsic ○ Diorite ■ Intermediate ○ Basalt ■ Mafic ○ Peridotite ■ Ultramafic ● In a solid, atoms and their bonds are always vibrating. As temperature increases, the vibrations _____, leading to melting. Pressure has the opposite effect, compressing the solid, making it more resistant to melting. ○ Increase ● Radioactive decay, impacts of meteors, initial collisions, and compression of materials by gravity are some of the sources of ______ for early Earth ○ Heat ● The melting of rock to form magma is influenced mainly by which of the following three factors? ○ Temperature ○ Pressure ○ Water content ● An ______ igneous rock is one that solidifies on Earth's surface. ○ Extrusive ● If the pressure and bond strength are sufficient to overcome vibrations due to an increase in temperature, a rock or mineral will ○ Remain solid ● Which of the following factors influence the composition of a magma? ○ Partial crystallization ○ Assimilation and magma mixing ○ The type of source area ○ The completeness of the melting of the parent rock(s) ● Select the three ways in which magma can travel through Earth's crust. ○ Magma can travel upward as rocks above magma chambers collapse. ○ Magma can travel in regions where tectonic forces have newly fractured solid rocks. ○ Magma can travel through existing fractures in rock, forming fissures and dikes. ● Match a factor on the left that determines how far magma can rise toward Earth's surface with its definition. ○ Magma pressure ● ● ● ● ● ● ■ Pressure of the overlying rock is directed toward the magma from all sides. ○ Density ■ Magma is less dense than surrounding solid rock and thus rises. ○ Gas pressure ■ Carbon dioxide and sulfur oxide bubbles form in magma, decreasing density of the magma. ○ Stress ■ Opening of fractures is induced by tectonic forces. The three primary factors that control rock melting are ________, ________, and the presence of water. ○ Temperature ○ Pressure An igneous rock that solidifies below the surface is a(n) ______ rock. ○ Intrusive A magma that does not flow easily is described as ______. ○ Viscous Source rock types and temperatures as well as other factors can affect the _______of magma. After magma forms, this property can be changed by crystallization, assimilation, or mixing. ○ Composition or viscosity Pressure from magma and ______ forces produce fractures through which magma can move. ○ Tectonic Select all the statements that are correct for cooling magma. ○ Magma can lose heat when it releases gases either underground or above ground. ○ When magma reaches the surface of Earth, thermal energy is transferred to the atmosphere and land surfaces by conduction and radiation. ○ At depth magma loses thermal energy to the surrounding rocks by conduction. ○ Groundwater can receive heat from magma by conduction. ● The higher a magma's viscosity is, the ______. ○ Slower it will flow ● Felsic minerals melt before _______ minerals. ○ Mafic or ferromagnesian ■ As a rock undergoes heating, the felsic minerals will melt before the mafic minerals because they melt at lower temperatures. ● An underground body of molten rock is a ________ chamber. ○ Magma ● All of the following are tectonic settings where large magma chambers can form, except ______. ○ Above existing lava fields ● Conduction, convection, and radiation of heat are the ways that thermal energy can escape from ________ as it cools. ○ Magma ● A magma chamber that is solidified is a _________. ○ Pluton ● Match the intrusion on the left with its definition on the right. ○ Dike ■ A sheetlike intrusion that cuts across layers in a hot rock ○ Sill ■ An intrusion that is parallel to the layers in the host rock ○ Laccolith ■ An intrusion that can eventually form a dome ● The solidified conduit, or volcanic _______, is exposed when the volcano erodes. ○ Neck or plug ● A magma chamber is ______. ○ an underground body of molten rock ● Which of the following are tectonic settings where large magma chambers can form? ○ In areas of continental collisions ■ This felsic magma builds up under the crust. ○ In the continental lithosphere within regions of hot spots and rifts ○ Above subduction zones ○ In the oceanic lithosphere above hot spots and within mid-ocean ridges