GLY1000 Exam 01 Study Guide Chapter 05 Geology 1 Physical examines the materials composing earth and seeks to understand the processes beneath its surfaces 2 Historical study the origin of earth and the development of the planet Earth is 4 6 billion years old Scientific Method Hypothesis is an untested explanation Theory a tested and viable hypothesis that has received much review Hydrosphere a dynamic mass of water that is always on the move evaporation condensation tides etc Atmosphere life giving gaseous envelope surrounding the earth Biosphere all life on earth Geosphere solid earth beneath the ocean and atmosphere 1 Crust thin rocky outermost skin of earth 2 Mantle 82 of earth s volume solid rocky shell Lithosphere crust and thick hard layer of rock that is present until the upper mantle Asthenosphere name of the mantle layer upper and lower 3 Core iron nickel alloy composition contributes to earth s magnetic field split into liquid outer core and solid inner core Continental drift the idea that the continents move about the face of the planet and explanation for the supercontinent s Pangaea deformation Plate tectonics theory that emerged from the concept of continental drift claimed earth s outer shell is broken into numerous slabs called lithospheric plates Boundaries 1 Convergent when one plate plunges under the other and descends into the mantle formation of major mountain belts 2 Divergent located where plates are pulling apart from one another occurs at oceanic ridges creation of new seafloor 3 Transform located where plates slide past each other movement of such nature usually results in earthquakes Continental margin the portion of seafloor adjacent to land masses Continental shelf the sloping platform material extending seaward from shore Continental slope steep seafloor extending down into the deep ocean basins Chapter 11 Rift valley a deep down faulted structure forming on the axis of ridge segments evidence that tensional forces are actively pulling the ocean crust apart Continental rift the elongated depression at divergent boundaries Subduction zones convergent boundaries sites where lithosphere is descending into the mantle deep ocean trenches form at the site of subduction partial melting also occurs as the plate plunges downward the heat and pressure at roughly 100 km drives the water out of the crust leading to some melting continental volcanic arcs volcanic mountain ranges will form as the partial melting creates volcanic activity that rises to earth s crust Ocean Ocean Convergence very similar to ocean continental convergence trench forms volcanic island arc forms Continental Continental large new mountain ranges form Transform boundaries connected with shallow earthquakes and seafloor fraction zones prominent linear breaks in ocean floor Mantle plume a cylindrically shaped upwelling of hot rock Hot spot an area of volcanism high heat flow and crustal uplifting as a plate moves over a hot spot a chain of volcanic structures known as a hot spot track forms Due to the magnetic alignment of iron rich minerals in lava and their flow at the earth s core 1 Polar wandering movement of the poles relative to continental drift 2 Magnetic reversal periodic shift of polarity Convection warm material rising and cold material settling within the Mantle serves as the mechanism for plate movements 1 Slab pull subducting slab sinks because it is colder and denser and mantle material 2 Mantle drag enhances plate motion when velocity of mantle rises 3 Ridge Push gravity driven force amplified by the elevated position of the ridges It has been suggested that mantle convection happens at two layers upper and lower mantle Chapter 06 Mineral any naturally occurring inorganic solid that has an orderly crystalline structure and a distinct chemical formula Basic Chemistry Atom contains a nucleus made of protons and neutrons Atom has an electron shell with valence electrons on the very outer edge that react with other atoms Isotope is the same elemental atom with a different number of neutrons affects the total mass number Ions are charged atoms opposites come together to form ionic bonds Covalent bond is formed by the sharing of a pair of electrons Octet Rule claims that atoms will gain or lose electrons until their valence shell contains eight electrons Physical properties of minerals 1 Luster appearance quality of light reflected from the surface 2 Translucence ability to allow light to pass through 3 Color 4 Crystal shape 5 Streak the color of the mineral in powder form 6 Tenacity a mineral s resistance to breaking or deforming 7 Hardness a measure of the mineral s resistance to abrasion or scratching a Moh s scale 10 minerals arranged on a scale of hardness from 1 10 diamond being the hardest 8 Cleavage the tendency for a mineral to break along planes of weak bonding 9 Fracture the type of breaking that occurs under pressure smooth irregular etc 10 Density specific gravity mass per unit of volume Only 8 elements make up the majority of rock forming minerals and 98 of earth s crust Mineral groups O Si Al Fe Ca Na K Mg 1 Silicate Group a Feldspars 50 or earth s crust most abundant b Quartz made almost completely out of silicon and oxygen second most 2 Non Silicate Group notably includes native elements gold silver copper diamond Ore Ore deposit is a naturally occurring concentration of one or more metallic minerals Chapter 07 Study in detail The Rock Cycle on page 166 of textbook Igneous rock forms as magma cools and crystallizes Magma molten rock generated by partial melting of rocks at earth s mantle When magma becomes less dense than the surrounding rocks it buoyantly rises when it reaches the surface it is then considered lava Crystallization at the surface creates extrusive volcanic igneous rock while crystallization below the surface is considered intrusive plutonic The rate of cooling strongly effects the size of the crystals slow cooling forms large crystals while fast cooling forms small crystals Igneous texture 1 Glassy rapid cooling at surface with high levels of silica 2 Porphyritic large crystals embedded in small matrix 3 Fine grained rapid at surface 4 Course grained form below surface Chemical Composition 1 Granitic felsic quartz granite rhyolite light colored silicates 2 Andesitic amphibole diorite andesite mixture of light and dark 3 Basaltic mafic Pyroxene gabbro basalt majority dark silicates 4 Ultramafic olivine pyroxene peridotite almost entirely dark
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