CEE 1030 1nd Edition Lecture 13: Earth’s InteriorOutline of Last Lecture I. ReviewII. Plate tectonicsIII. Geomagnetic reversalsIV. Magnetism of seafloor rocksV. Workings of plate tectonicsa. Three types of plate boundariesVI. Plate tectonics: predictionsVII. What drives plate motions?VIII. Review, continuedIX. Measuring plate motionOutline of Current Lecture I. Calculating the density of EarthII. SeismologyIII. Boundariesa. Crust-mantle boundaryb. Core-mantle boundaryIV. Seismic Tomographya. The coreb. The mantlec. The crustV. Earth’s internal heat engineCurrent LectureI. Calculating density of Eartha. The average density of Earth is greater than densities of crust and mantle, so logically the center of the Earth must be more denseII. Seismologya. Study of seismic waves generated by earthquakes and large explosionsb. Seismic waves move at different velocities through rocks with different propertiesc. Types of wavesi. P waves transmitted through solid and liquidii. S waves (“shaking” waves) cannot be transmitted through liquidIII. Boundariesa. Crust-mantle boundaryThese 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.i. “Moho”ii. Boundary between the crust and the mantleb. Core-mantle boundaryIV. Seismic tomographya. Can see variations in the lithosphere, subducting slabs, etc.b. Earth’s layered structurei. Layers defined by1. Composition2. Physical properties such as mechanical strengthc. The corei. Iron-rich sphere1. Inner core: solid inner sphere2. Outer core: liquid outer layerii. Responsible for Earth’s magnetic fieldiii. Iron is the only common element in the solar system that has the density to form the coreiv. Early differentiation: dense iron sank to form the core, light silicate minerals formed the mantlev. Earth’s magnetic field1. Movement of electrically-conducting liquid iron in outer core: geodynamod. The mantlei. Solid rocky shellii. Composition: ultramafic rock, peridotitee. The crusti. Earth’s outer skinii. Two distinct types (different ages and compositions)1. Oceanica. Oceanic crust composition: mafic igneous rock basaltb. Young and thin2. Continentala. Continental crust composition: felsic igneous rock andesiteb. Some parts of rocks are ancientf. Layers defined by physical propertiesi. With increasing depth, Earth’s interior gets warmerii. Lithosphere: relatively cool, outer rigid shell of Earth’s crust and uppermost mantleiii. Asthenosphere: soft, weak layer of upper mantle beneath the lithosphereV. Earth’s internal heat enginea. Earth’s temperature gradually increases with depth at a rate known as geothermal gradientb. Heat is transferred by convectionc. Major sources of Earth’s internal heat:i. Radioactive decay of isotopesii. Iron is crystallized to form solid inner coreiii. Colliding particles during formation of
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