GSC Test #1 Study Guide
GSC Test #1 Study Guide GSC 110D
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This 12 page Study Guide was uploaded by Amanda Hillegass on Thursday February 12, 2015. The Study Guide belongs to GSC 110D at University of Miami taught by Terri Hood in Spring2015. Since its upload, it has received 256 views. For similar materials see The Earth System (lecture) in Geology at University of Miami.
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Date Created: 02/12/15
GSC 110 Dr Terri Hood Exam Date 2182015 Study Guide for Exam 1 1 What is geology a quotgeoquot earth logos the study of b Visualizing systems and processes in space and time not on a human scale i Different scales ranging from microscopic to billions of years ii Spacetime phenomena when you get to space you have to account for combination of space and time ex light years 1Ex looking at the sun 8 minutes in the past c Principle Subdisciplines of Geology i Engineering Geology the stability of geologic material s at the Earth s surface so we can build on it etc ii Environmental Geology Interactions between the environment and geologic materials and the contamination of geologic materials iii Geochemistry Chemical compositions of materials in the Earth and extraterrestrial objects radiation iv Geochronology The age in years of geologic materials the Earth and extraterrestrial objects v Geomorphology landscape formation and evolution vi Geophysics physical characteristics of the whole earth and of forces in the Earth vii Hydrology groundwater its movement and its reactions with rock and soil viiiMineralogy the chemistry and physical properties of minerals ix Paleontology fossils and the evolution of life as preserved in the rock record x Petrology rocks and their formation xi Sedimentology sediments and their deposition xii Seismology earthquakes and the Earth s interior as revealed by earthquake waves xiii Stratigraphy the succession of sedimentary rock layers xivStructural Geology Rock deformation in response to the application of force xv Tectonics regional geologic features and plate movements and their consequences 2 Universe Formation and Nucleosynthesis a Cosmology the study of the overall structure of the universe b Big Bang Theory i Universe started as a singularity point in space time where physics breaks down like black holes ii Moment of creation energy transforms into matter and the universe expands hydrogen and helium are created c Formation of Universe and Nucleosynthesis formation of the elements i Matter existed as a giant nebula expanding cloud of H and He where relative densities are magni ed by gravitational force dense materials get denser 1Forms galaxies 2Forms smaller nebulae that contract to form protostars with increasing temperature 3Protostar becomes a star when the central pressure grows high enough for nuclear fusion aH gt He initiation of star s luminescence d Stages in a Star s Existence i Main sequence stable phase balanced forces of H fused into He steady burning ii Inverse time relationship larger mass more fusion burns out of main sequence faster 1Smal 100 billion years 2Average sun 10 billion years 3Large few billion years iii What happens after main sequence 1Runs out of H because it can t balance inner part of star collapsing inward increase in pressure and temperature 2For stars less than 15 solar masses aRed Giant outer layers expand and cool dense center bElements up to carbon form in moderate sized stars c Fuel He is used up and core collapses followed by rebound explosion dProduces a planetary nebula surrounding a white dwarf star i White Dwarf different emissions varying forms ex ring and hourglass nebula 3For stars greaterthan 15 solar masses aRed Supergiants high temperature and pressure form elements up to iron at core exothermic process release energy selfsustaining but takes a lot of energy to start bFuel Si is used up and core collapses followed by rebound explosion supernova i All elements heavier than Fe are made in supernova cAt center is either a neutron star very smooth surface small dense heavy liquid interior like a ball or black hole 3 Solar System Formation and Earth s Interior a Nebular Hypothesis i Solar systems form from condensed space matter coming together by mutual gravitational pull Explains major features of our solar system ii Protoplanetary Disks aka early stages of formation are found in other starforming regions like the Orion Nebula b Formation of Our Solar System i 46 billion years ago ii Nebula of material from previous stars and at least one supernova condense and contract into rotating disk rotates because of uneven distribution of mass 1Shockwaves from supernova can rearrange a nebula iii Protostar forms in center 99 of material ends up here iv Rings of material where centrifugal force balances out the gravitational pull towards center rings will turn into planets and moons and protostar fuses into the sun 1nner planets are rocky quotterrestrial planetsquot Mercury Venus Earth Mars v First burst of solar wind gets rid of most lighter material from inner solar system and its effects die down with distance why outer planets have lighter elements quotJovian gas giantsquot vi 2006 Pluto becomes quotLarge Kuiper Belt Objectquot aka dwarf planet because of a different elliptical orbital that overlaps with this belt others include Quaoar Sedna Xena etc c Some Interesting Aspects of Our Solar System i Jupiter s gravitational pull prevented asteroid belt from forming into a planet solar system is chaotic and inner planets rotate faster than Jupiter outwards asteroids get pulled in both directions and Jupiter s pull wins ii Effects of early rogueorbit planetesimals 1PutoCharon system moon is larger 2Anamolous spin of Uranus tumbles forward probably due to large glancing blow 3Formation of Earth s moon due to a collision allowed for formation of intelligent life d Formation of Moon i Formed within rst 100 million years due to a collision of a planetesimal with Earth ii Much of Earth s outer layers went to orbit and formed a ring that coalesced into the moon matches layers of Earth 4 Evidence for Earth s lnterior a Earth s lnterior i Early Impressions Europe 1600518005 caves re amp brimstone rocky sponge with open caverns lled with air water or molten rock ii Current View Earth s interior consists of distinct layers b Sources of Evidence i Direct Evidence recent only penetrates Earth s outermost portion 1Limited lines 2Deepest mine shaft 35 km deepest well 12 km 3Earth s actual radius 6370 km ii lndirect Evidence 1Most evidence comes from this aEarth s Density water s 10 gcc typical rocks 23 gcc bEarly estimates of Earth s density comes from plumb bob experiment in an expedition of the Andes Mtns gt shows gravitational pull of mountains i Maskelyne astronomermathematician said this could be used to calculate Earth 5 average density it equals 55 gcc twice that of normal surface rocks 1 Cannot be lled with caverns because density must increase with depth c How does density increase with depth i Gradually or more dramatic steps 1 Gradual Earth s mass would not lie in its center centrifugal forces would atten it to a disk quotequatorial bulgequot a Only a slight equatorial bulge with most mass concentrated at the core 13 gcc b NOT GRADUAL c Evidence for Structure of Earth s Interior i Seismic waves caused by earthquakes sudden ruptures in rocks ii 3 Types 1Surface Waves large motion like pond ripple causes most earthquake damage travels along outersurface of earth 2PWaves body wave PressurePrimary fastestquot travel by compression like sound waves 3SWaves body wave SecondaryShear slowerthan P but faster than surface single particles move at 90 degree angles to direction of wave initiation can ttravel through liquid or gas gt S wave shadow zone aSWave shadow zone shows presenceposition of liquid outer core because swaves can t travel through liquid bRefraction pattern ofpwaves shows presenceposition of solid inner core iii P and Swaves can be bentrefracted when going through materials which indicates presencemagnitude of physical properties iv Seisomographs record vibration due to seismic waves v Situations where waves reached a spot far from epicenter of earthquake fasterthan a spot near it 1Focus place below surface where earthquake originates 2Epicenter place on earth s surface right above the focus vi Mohorovicic determined that the earth s upper mantle lets waves travel faster than through the earth s crust this crustmantle boundary is called the quotmohoquot vii Established network of seismic monitoring stations following WWII bombing d Evidence for Composition of the Earth s Interior i Rocks from Earth 5 mantle 10phiolites ocean crustmantle brought to surface via tectonic processes 2Xenoliths quotStranger rocksquot deep wall rock brought up in magma ii High PressureTempera ture Experiments 1Use diamond wall and lasers to superheat samples iiiMeteorites 1Extraterrestrial rock pieces that fall to Earth many are from asteroid belt 2Undifferentiated aquotchondritesquot Witness falls primordial composition of solar system and starting composition of early earth before melting and segregation contain crucial amino acids 3Differentiated aquotstony mantle and iron core early planetesimal pieces large enough to undergo meltingsegregation fusion crust amp metal crystals inside i Believed to have similar inner composition to earth s interior layers e Accretion of Early Earth i Homogeneous accretion model earth s initial material was similar but radioactive decaybombardmentincreasing pressure led to melting and segregation according to density 1Densest at center ii Earth s interior is made up of different layers that have been given names based on composition and behavior iii Composition main elements 1Crust Si O 2Mantle Si 0 Fe Mg 3Core Fe Ni iv Behavior 1Lithosphere Rigid brittle 2Asthenosphere Semiplastic behavior 3Mesosphere more solid behavior 4Outer core liquid 5nner core solid 5 Plate Tectonics a quotContinental Driftquot i Alfred Wegner 1930s German Meteorologist ii Coastlines of 7 continents t together like a puzzle evidence leading to hypothesis that they were once together 1M0untain Chains and rock formations match up 2Geographic Distribution of fossil remains a Glossopteris Lystrosaurus fossil distribution only makes sense if continents were connected 3 Glacial deposits direction of ice movement aGlacial sculpting and fractures b c bOnly makes sense with connection of Southern continents 4Envir0nmenta Indicators match up in latitudinal bands aGives position of supercontinent Pangea quotall landsquot relative to equator and poles I Continental Drift i Compelling evidence but there wasn t a reliable mechanism so the theory was shot down ii Early 19605 accurate ocean bottom topography from Cold War submarine navigation revealed linear mountain chains and deep trenches iii Need to be able to detect submarines high resolution mapping of magnetic signatures of ocean oor and world ocean oor mapping 1Showed stripes of greaterlesser magnetization Earth s Magnetic Field and Magnetization of Rocks i Heat quotCoriolis forcequot due to Earth s rotation cause liquid iron outer core to move in complex helical patterns creates earth s magnetic eld looks like if there was a giant bar magnet dipole at earth s center from space 1Conventionally drawn with arrows pointing from North to South poles Earth s magnetic eld de ects much solar and cosmic radiation coming toward us iii Some charged particles get channeled to the poles atmospheric gases Northern Lights Aurora Borealis and Southern Lights Aurora Australis Magnetization of Rocks i Magnetic Minerals 1Rotation of electrons around an atom s nucleus creates a small magnetic dipole 2For nonmagnetic materialsminerals these dipoles tilt in random directions cancelling each other out 3ln magnetic minerals these dipoles can permanently align because of an external magnetic eld permanent magnet ex magnetite lodestone 4ln rock that forms from cooling lava magnetic minerals and earth s magnetic led align and are frozen into position once solidi ed 5Geologists found reversals of the lava that had been magnetized opposite of the present eld reversed NgtS 6quotPolarity Chronsquot established by dating of reversals in continental lava ow for last 45 million years reinterpreting magnetic stripes on sea oor 7Symmetric magnetization patterns on each side of sea oor suggests that new crust is created there which is magnetized in the direction of that moment sea oor is spreading at midocean ndges ii 80cean crust dating showed youngest rock was present at mid Ocean ridges and that it gets older as you move away aAowed for dating of quotmagnetic stripesquot gt extend record of Ea h 9Continental Drift theory modi ed to new theory of plate tectonics where continental crust is a lower density than oceanic crust aPate movement is a result of convection in earth s mantle This happens because heat radiates out from Earth s center and the ability of the mantle to ow 10 Earth s surface is broken into about 20 major plates with many microplates 11 Plates sections of lithosphere that move on asthenosphere as a coherent unit continental lithosphere 150 km in thicker than oceanic 10100 km 12 Mantle asthenosphere convection cause lithospheric plates to move relative to one another 13 Simple convection cells are not valid proven by new studies 14 Plate boundaries are marked by frequent earthquakes because plates move laterally d Types of Relative Plate Motion at Plate Boundaries i Divergent moving apart lithosphere being made ii Convergent coming together lithosphere being destroyed iii Transform moving side by side neither created nor destroyed e Divergent Boundaries i quotSpreading centersquot most on ocean oors in middle of ocean mid ocean ridges center has rift valley where lithosphere s made decompression melting for magma coming up also pulling motion ii Sites of shallow focus earthquakes and wellbehaved low viscosity volcanoes iii Iceland is on MidAtlantic ridge iv Sometimes rifting begins below continents new ocean at thinning crust v Triple Junction of 3 plates at spreading ridges ex Red SeaGulf of AdenEast African Rift Valley f Convergent Plate Boundaries i Subduction Zones one plate plunges beneath another ii Crust Types 1Oceanic Oceanic island arc usually volcanic creates tsunamis from earthquakes 2Oceanic Continental classic subduction zone where land plate oats because it s thicker and less dense 3Continental Continental CollisionSuture Zone pileup because densities are the same can double thickness of continental lithosphere ex Himalayas Urals Mtns Appalachian Mtns alf crust isn t being destroyed pressure builds up behind collision zone until it breaks to form suture zone iii Subduction Zones strong earthquakes shallowdeep focus and explosive volcanoes 1Convergent mostly deep focus and unpredictable volcanoes 2Ex aAndes Mtns Shallow plunge angle spread out foci bJapan Verticalsteep plunge angle close together foci g Transform Boundaries i Fault zone 2 plates move past each other side by side ii Ex San Andreas Fault in California h Hot Spots i Deep mantle source of molten material not associated with plate boundaries ex volcano 1Ex Yellowstone National Park sits on large magma chamber associated with a hot spot manifests in thermal features like geysers and hot springs 2Ex Hawaii classic part of Emperor Seamount Chain line of extinct volcanoes ii Plate Motions Measured 1Relative Motion relative to each other via magnetic laser ranging 2Absolute motion relative to a xed point in mesosphere i Plate Motion and Convection in the Mantle i Initial theories of plate tectonics show simple ordery convection cells with plates riding them passivey ii Convection cells in asthenosphere or whole mantle iii More evidence suggests 1Plates play a part in determining their motion and boundaries a Ridge Push bSlab Pull subducted part acts as anchor to drag down rest of plate 2Convection patterns in mantle aren t simple a Thermal anomalies in mantle warmer rising cooler sinking iv Mantle convection model with upper and lower zones of convection that exchange materiain certain zones may work j Plate Boundaries on Maps i Divergent shown by two parallel lines ii Transform connect other boundary types shown by a single line iii Convergent Shown by line with triangles attached their tips point towards winning plate the one on top of the other iv Why do spreading ridges have so many transform boundaries 1Plates are on a sphere moving around a quotspreading polequot 2Sections of same ridge are spreading at different speed require a break to accommodate this 6 Minerals a b Rocks and Minerals i Monomineralic rocks made of only one mineral ex limestone ii Polymineralic most rocks are made of several minerals ex granite iii How do you qualify as a mineral 150id at STP 1 atm 25 degrees Celsius 2ln0rganic No C H O N S 3Have speci c chemical composition certain atoms in certain proportions has a neat formula 4Have characteristic crystal structure atoms arranged in a speci c fashion aDifference between diamondand graphite also strength of their bonds 5Naturalyformed nonsynthetic iv Mineral Identi cation how to know what s what Mineral Classi cation i Divided into classes based off composition ii 7 Major classes based on principle anion present 1Native Elements occurs in pure form aMetas are the earliest documented use of native elements bNonmetals diamond and graphite are only different structures of carbon diamond strong covalent bonds graphite has weak Van der Waals bonds in one direction Oxides aAnion 0239 bEx Magnetite Corundum c Many are important ores mined for economic value Sul des 2 3 aSZ39 bBonded to metal cation c Ex pyrite galena sphalerite dForms under reducing conditions and many important ores Sulfates 35042 bEx gypsum epsomite HaHdes aCl F halogens bEx Halite salt Fluorite toothpaste Carbonates aCO3239 bEx Calcite c Main component of rock limestone which makes up most of Florida dMost common carbonate mineral test by dropping HCl on it 7Silicates aSiO4439 bSilica silicate tetrahedron 4 5 6 c Most common class of minerals on earth divided into different subclasses depending on connection of silicatetrahedra i Independent Tetrahedra no connectivity ex olivine iiTwo Tetrahedra share one corner ex epidote iii Rings usually between 6 tetrahedra aka cyclosilicates ex beryl iv Single Chain chain connected at two corners ex pyroxene vDouble Chain 2 connected chains ex amphibole vi Sheet full sheet of chains share 3 corners ex mica vii 3D Framework all corners connected ex quartz 7 Rock Intro and Igneous Rocks a Rocks b C d i Mostare made of minerals some are made of glass volcanic glass obsidian and some are made of organic mattercoal amber ii Classi ed according to how they form genetic classi cation 3 types 1lgneous quotignisquot fire solidi cation of molten rock aka quotmeltquot 2Metamorphic quotmetaquot change morph form preexisting rocks change in response to increased temperaturepressure 3Sedimentary forms from fragments or dissolved parts of previous rocks at earth s surface Igneous Rocks i Formed by solidi cationfreezing of melt 1Lava melt erupting from volcano at earth s surface 2Magma melt that exists below earth s surface 3These freeze between 6501100 degrees Celsius ii Extrusive lava frozen at earth s surface iii Intrusive magma frozen below earth s surface ex granite boulders iv Geotherm change in temp of Earth with depth plotted as a curve on a PT pressure temp diagram Magma Formation i Conditions that lead to melting 1Decompression Melting Decreasing pressure make things solid and increasing temps make it melt however the deeper you go pressure wins out and mantle gets more solid so when hot rock rises toward surface it melts 2Heat Transfer Melting magma rises up and heats overlying crustal rock melting it melting points mantle 1100 Celsius Crustal Rock 650800 Celsius 3Addition of Volatiles water and gases decreases melting temp EX H20 C02 N2 H2 502 Major Types of Magma by SiOz i Silicic felsic 70 silicarich ii Intermediate 55 iii Ma c 50 Mg Fe rich iv Ultrama c 40 very Mg Fe rich v This effects their behavior vi Why is there such a range in composition 1Source Rock Composition Mantle source ultrama c ma c Crustal source intermediate siicic 2Partial Melting incomplete melting of source rock aMineras with lower melting point incudedinto magma higher not included bMagma moves away from source now different composition silicarich minerals have lower melting point than ma c minerals so partial melting more silicic metthan source rock 3Magma Contamination as magma moves up it can stallpark can melt some surrounding rock via heat transfer which is mixed into magma or blocks fall in and become assimilated alters magma composition usually becomes more silicic 4Fractional Crystallization ma c minerals freeze at higher temps than siicic minerals they form rstwhen magma cools denser ma c minerals settle out and remove Fe and Mg from magma makes remaining more silicic as it cools aCan make layered igneous rock ex Bushveld Complex South Africa world s richest source of platinum 8 Bowens and Igneous Formations a Order ofFormation of Minerals from an Igneous Melt i 19205 Mineralogist Bowen ran systematic experiments to determine the orderthat minerals form from an originally ma c melt and corresponding changes in melt composition through time ii Mineral Crystallization sequence Bowen39s Reaction Series b Bowens Reaction Series i 2 quottracksquot happening at once with decreasing temperature 1Discontinuous Series distinctly different minerals form successively with changing structure and composition 2Continuous Series different versions of same mineral with shift in composition ii Gets increasingly silicarich through series c Discontinuous Series i There is overlap in times for crystallization Mineral Structure Olivine Isolated Silica tetrahedra Pyroxenes SingleChain Amphiboles Double chain Biotite Fe rich mica Sheet d Continuous Series i Plagioclase Feldspar 3D framework of silica tetrahedral ii Carich gt Narich complete solid solution series iii When 10 of original melt volume is left remaining melt is siicic iv Formation of quartz3D framework muscovite Sheet k rich mica K fedspar 3D framework e Igneous Rocks f 9 i Classi ed according to 1Composition 2Crystal size texture alntrusive slow cooling large crystals bExtrusive quick cooling smaller crystals 3ncreasing silica Increasing viscosity ii Ma c magmas ow readily often are extrusive basalts most common ma c igneous rocks iii Silicic magmas are resistant to ow mostly intrusive ex granites most common silicic igneous rocks Intrusive Igneous Formations i Pluton solid body of igneous rock emplaced beneath earth s surface plutonic rocks 1Ex Mount Rushmore South Dakota Stone Mountain Georgia ii Sill intrusion of magma between layers of preexisting rock horizontal intrusion concordant iii DikeDyke intrusion of magma across existing rock structure vertical intrusion discordant iv Volcanic Neck exposed throat of a volcano where magma solidi ed in vent and outlast surrounding volcano 1Ex Shiprock New Mexico Devil s Tower Wyoming v Columnarjointing polygonal columns formed by contraction as lavamagma cools 1Ex Salt Flat Death Valley CA Mud Cracks Afghanistan Giant s Causeway Ireland 2Geography determines whether it s devoted to giants or devils two common names used vi Batholith big group of plutons more common than individual 1Usually granite forming 1520 miles deep 2Exposed at surface after uplift and erosion often forms core of mountain ranges aEx Sierra Nevada Yosemite El Capitan Extrusive Igneous Formations i Flood basalts largest cooedlava formations 1Ex Columbia River Wash Oregon Idaho started erupting out of giant ssures 15 million years ago ii Traps largest ood basalts that may be the result of quotsuperplumesquot coming from the coremantle boundary 12 biggest Siberian Traps in Russia end of Paleozoic Era and Decan Traps in India Dinosaur Extinction are associated with the 2 biggest mass extinctions in Earth 5 history
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