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Chapter 3

Concept #6 Quiz

Concept #6 Quiz
Choose the best possible answer to the following questions about Key Concept 6 "The production and evolution of magma."

This activity contains 9 questions.

	On a global basis, most of the world's magma is generated in which part of the Earth?   convergent plate boundaries the lower crust plate tectonics the upper mantle

	Match the appropriate term associated with the production of magma to its best description. Using the pull-down menus, match each item in the left column to the corresponding item in the right column. high levels are necessary for melting of rocks higher values of this require greater temperatures for melting cause rocks to melt at lower temperatures, magnified by an increase in pressure, important at convergent plate boundaries occurs when confining pressure drops significantly, like under the ocean ridges 2.1 heat A B C D 2.2 pressure A B C D 2.3 decompression melting A B C D 2.4 volatiles A B C D

	A heated crystalline solid most likely melts when ________.   ions vibrate so much that the vibrating breaks some of the chemical bonds heat expansion of the chemical bonds causes them to break heat expansion of the ions breaks apart the crystalline solid chemical bonds melt

	What process (or processes) can aid in generating magma from solid rock?   an increase in heat (high temperature) a decrease in the confining pressure (decompression) the introduction of volatiles (e.g., water) all of the above

	What is "magmatic differentiation"?   The process by which the same igneous rock may produce different magma compositions upon melting. The process by which the same magma may produce different composition igneous rocks. Crystal settling may produce different melting conditions for a rock in different plate tectonic scenarios. Heavier crystals float on the top of the magma in the magma chamber producing a layered igneous rock upon complete solidification.

	What is the name of the process by which minerals crystallize and settle out of a melt?   Bowen's reaction process magma mixing crystal settling extrusion assimilation

	Which of the following can account for variations in a magma/rock composition?   a. crystal settling b. magma mixing c. assimilation of "foreign" rocks by the magma a. and c. only All of these.

	Why do all magmas create dominantly silicate minerals upon cooling?   Si and O are the most abundant elements in the magma. Al and Si are the least abundant elements in the magma. Si and O are the least abundant elements in the magma. Al and Si are the most abundant elements in the magma.

	A single magma may generate several mineralogically different igneous rocks.    True  False

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