GEOL 1040 1st Edition Lecture 13Outline of Last Lecture XXIII. Igneous Compositiona. Dark Mafic Mineralsb. Light Felsic mineralsc. ExamplesXXIV. Origin of Magmaa. Generating magma from solid rockb. 3 Mechanisms rock melt byXXV. Role of Heata. Geothermal Gradientb. Conductionc. Radiant Heat transferd. Convectione. Transferring thermal energy via plate tectonicsXXVI. Role of pressurea. Higher pressure b. Low Pressure c. Decompression XXVII. Role of heat and mantle convection away from plate boundariesa. Hot spotXXVIII. Role of Volatilesa. Flux meltingb. Water acts as a volatile and lowers melting temperaturec. Important for subduction zones where oceanic lithosphere descends into the mantleXXIX. Magma and Plate tectonicsa. Decrease in Pressureb. Increase Temperaturec. VolatilesOutline of Current Lecture I. Melting and Plate Tectonicsa. 3 ways to melt rockThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.II. Evolution of magmaa. Magma originatesb. Changec. Magma mixingd. AssimilationIII. Mineral Resources and Igneous Processesa. Many metal ores are produced by igneous processb. Formed by:c. Hydrothermal solutionCurrent LectureIV. Melting and Plate Tectonicsa. 3 ways to melt rocki. Decompression1. Decrease in pressure2. Rifting= extension3. Found at Mid Ocean ridges4. As the plate stretches out, the idlearea is thinner with less pressure.a. This causes melting ii. Flux1. Adding volatiles2. Happens at convergentboundaries and subduction zones3. Adds H20 and CO2 to changemelting point iii. Increase intemperature1. Hot Spots2. Plumes3. In Hawaii, yellow stone, Iceland : Confirmed Hot Spot4. The increase in temperature from the hot materials melts the rockV. Evolution of magmaa. Magma originatesi. Almost all originate from basaltic metals from the mantleb. Changesi. Crystallization1. Magma rises from depth2. Cools as it rises3. Crystallizes out minerals4. Left over magma has different composition than original5. Continues to the surfacec. Magma mixingi. Happens beneath surface d. Assimilationi. Melt the rock1. Melted and mix in sedimentary rock, changing its compositionVI. Mineral Resources and Igneous Processesa. Many metal ores are produced by igneous processb. Formed by:i. Magmatic segregation- separation of liquids or minerals from main magma systemc. Hydrothermal solutioni. Originate from hot metal rich
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