CEE 1030 1nd Edition Lecture 13 Earth s Interior Outline of Last Lecture I Review II Plate tectonics III Geomagnetic reversals IV Magnetism of seafloor rocks V Workings of plate tectonics a Three types of plate boundaries VI Plate tectonics predictions VII What drives plate motions VIII Review continued IX Measuring plate motion Outline of Current Lecture I Calculating the density of Earth II Seismology III Boundaries a Crust mantle boundary b Core mantle boundary IV Seismic Tomography a The core b The mantle c The crust V Earth s internal heat engine Current Lecture I II III Calculating density of Earth a The average density of Earth is greater than densities of crust and mantle so logically the center of the Earth must be more dense Seismology a Study of seismic waves generated by earthquakes and large explosions b Seismic waves move at different velocities through rocks with different properties c Types of waves i P waves transmitted through solid and liquid ii S waves shaking waves cannot be transmitted through liquid Boundaries a Crust mantle boundary These 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 IV V i Moho ii Boundary between the crust and the mantle b Core mantle boundary Seismic tomography a Can see variations in the lithosphere subducting slabs etc b Earth s layered structure i Layers defined by 1 Composition 2 Physical properties such as mechanical strength c The core i Iron rich sphere 1 Inner core solid inner sphere 2 Outer core liquid outer layer ii Responsible for Earth s magnetic field iii Iron is the only common element in the solar system that has the density to form the core iv Early differentiation dense iron sank to form the core light silicate minerals formed the mantle v Earth s magnetic field 1 Movement of electrically conducting liquid iron in outer core geodynamo d The mantle i Solid rocky shell ii Composition ultramafic rock peridotite e The crust i Earth s outer skin ii Two distinct types different ages and compositions 1 Oceanic a Oceanic crust composition mafic igneous rock basalt b Young and thin 2 Continental a Continental crust composition felsic igneous rock andesite b Some parts of rocks are ancient f Layers defined by physical properties i With increasing depth Earth s interior gets warmer ii Lithosphere relatively cool outer rigid shell of Earth s crust and uppermost mantle iii Asthenosphere soft weak layer of upper mantle beneath the lithosphere Earth s internal heat engine a Earth s temperature gradually increases with depth at a rate known as geothermal gradient b Heat is transferred by convection c Major sources of Earth s internal heat i Radioactive decay of isotopes ii Iron is crystallized to form solid inner core iii Colliding particles during formation of Earth
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