Earths Science 1121 Midterm 1 Study Guide PDF

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This is the midterm study guide for Earth Science 1121 taught by Professor Lower. This midterm summary includes notes taken in lecture along with notes on the worksheets and extra assignments that were given over the course. ...

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Exam Percentages: Honesty: 1, 2% Intro: 6, 11% Scientific Method:9, 16% Universe: 10, 18% Solar System: 10, 18% Continental Drift/Earthquakes: 9, 16% Volcano: 10, 18% Total: 55, 100% Single pdf of all slides: https://osu.box.com/s/c3p4v6qjlnsj3xota950qfckakij5wpf Scientific Method Thought- (complex  and cautious) distinguishes humans, developed across thousands of generations and lends to curiosity, insight, and the ability to learn Ancient peoples thought the universe was geocentric (Heavenly bodies move circle around a motionless Earth) ● Held as a religious dogma for 1,500 years ● Ptolemy (100-170 A.D.) Greek Astronomer came up with this theory ○ Incorrect, but made since because the sun rose in the East and set in the West The first science was used to observe and record the positions of planets and stars in order to tell time ● Ancient civilizations needed to tell time because of hunting and agriculture ● Stonehenge was built nearly 5,000 years ago for these purposes ○ Began building in ~3,000 B.C. in Southern England ○ Continued to be built for around 1,000 years ○ 30 ton stones moved with sleighs The Renaissance in Europe spawned a new age of scientific exploration ● Copernicus (1543) Polish Cleric ○ Published evidence for heliocentricity ■ Heliocentricity describes that the planets circle the star of their solar system ● Circular Universe ● Sun in Center

● Circular Orbits (Not quite correct) ● Galileo (1564-1642) Italian Mathematician and physicist ○ Observed moons and planets with a telescope ○ Invented the telescope ○ First scientist to write in everyday language (Italian) rather than Latin ○ Fundamentally changed the Church’s view of the Solar System ○ The Starry Messenger describes telescopic observations ● Newton (1642-1727) English Physicist and Mathematician ○ Planetary motion described by his Theory of Gravity ○ NATURAL LAWS (NOT DEITIES) GOVERN NATURAL EVENTS ○ Provided physical explanations for Galileo’s observations Our ideas of the universe changed because humans invented new tools (e.g., telescopes) to make better observations of the natural universe Science is NOT… ● A collection of facts or answers ● A way of proving concepts (That is mathematics) Science can disprove concepts or ways of thinking. Science must also be able to test concepts. Science is a NEVER ENDING cycle. Scientific Method at Ohio State 1) Scientist makes a hypothesis based on observations or experiments 2) Scientist makes a funding proposal to a funding agency like NSF, NIH, or DOE a) 12-15 Pages b) 6 Month Peer-Review c) < 10% of Proposals are Funded 3) Successful proposals receive money to support their research a) University receives overhead = 50% of grant 4) Research is conducted by professor, post-docs, and students 5) Peer-Reviewed publication or presentation at a conference Batelle ● Established in Columbus is 1929 by Gordon Battelle ○ Battelle made his fortune in steel ○ Best known for and made most money from Xerox ● Generates $6.5 Billion in R&D activity annually and employs 22,000. Gravity = G(m1*m2)/(distance^2)

G = 6.67e-11 Universe A) Light and Stars B) Origin of Universe C) Gravity and Newton D) Scientific Test of Horoscopes Star ● Ball of gas made of Hydrogen and Helium (H and He) ○ Hydrogen and Helium were the first existing elements from the big bang ● Stars formed 400 million years after the Big Bang ● Held together by gravity ● Generates energy through nuclear fusion ○ Electromagnetic radiation like radio waves and visible light ○ Moving at 3e8 m/s ● Each star has a birth and death (life cycle) Wavelength is measured in meters Electromagnetic Radiation of our Sun ● Sun is our main source of light to the Earth ● Earth’s atmosphere is transparent to ROYGBIV ● Sun emits greatest proportion of energy in ROYGBIV - Shortest wavelength is gamma rays -Redshift = the universe is expanding -Light’s wavelength increases, shifting to the red end of the spectrum -Doppler effect = The increase in frequency of sound and light waves -Change in pitch -Used to measure the speed at which stars and galaxies are moving towards and away from us (redshift, blueshift)

Solar System and Earth -Mt. Rainier rocks: Rhyolite, Granite -Mt. Rainier minerals: Quartz -Course grained rock: Gabbro -Rocks that form in subsurface: granite, gabbro

-Minerals that are felsic: quartz, mica -Rock found in the middle of the Pacific Plate: basalt -Andesite in Andes Mountains -South America -Subsurface waves are p waves, intrusive -Front of the p wave to the front of the S wave -Dacite: -higher melting point than rhyolite -leaves flat volcanoes -Rhyolite: -high viscosity -leaves cone shaped volcanoes -Basalt: -low viscosity -Antcline: rock formation best described as an upside down U -Syncline: rock formation best described as a U -Clastic rocks: contains solid fragments and grains of preexisting rocks or shells cemented together -Chemical rocks: made from minerals precipitated directly from water -Biochemical rocks: consist of shells of organisms (coral) cemented together -Slower cooling = bigger crystals -Viscosity: -Higher viscosity = slower flow -Higher silica content = higher viscosity -Higher temperature = lower viscosity -Higher gas content = lower viscosity -A fault ends at a brittle ductile transition -Newer parts of the crust are warmer and less dense -Crust = lithosphere -Lithospheric plates are only made up of oceanic and continental crust -Thrust fault = a reverse fault with a very shallow dip -Compressional stress causes a thrust/reverse fault -Normal fault = the hanging wall moves down the slope -Normal fault is caused by tensional stress -Reverse fault: the hanging wall moves up the slope -Strike slip fault: horizontal movement caused by shear stress -Isostacy = rise of subsidence of the crust until the mass is buoyantly balanced -Asia, Indian collision has all three fault types

-Mesosphere: the mantle between the bottom of the asthenosphere and the core mantle boundary -Asthenosphere: the region of mantle where rock becomes ductile -Youngest plate will always be on top -Continental crust is 45 km thick -Oceanic crust is 8 km thick -Craton: A piece of crust that has not experienced tectonic deformation -Outer core: iron is molten and exists as a liquid -Fringing reef: A reef formed at a specific depth off an island Nebular Hypothesis Proposed by Laplace (French Mathematician, 1749-1827) ● Our solar system originated ~around 4.5 billion years ago ● A large cloud of dust and gas (H and He) collected in the region that is now occupied by our solar system ● Gravity pulled it all together and it started to spin ● All planets orbit in the same plane ● Most mass is in the center of the solar system (the sun) ● Fusion begins to heat up the solar system ● Terrestrial Planets form nearer to the sun, materials that remain solid at high temperatures ● Gas Planets form further away with similar composition to the original nebula Earth ● Earth is in the habitable zone due to liquid water ● Atmosphere, gas envelope ○ N2, O2, and Water Vapor ● Hydrosphere, the blue liquid water and water cycle ○ Cryosphere, the frozen world (global climate change) ● Biosphere, green and life ○ C and H2O ● Lithosphere, the solid Earth ○ Si and O ● Magnetic Field Edge of the Solar System ● Populated by fragments of ice and rock, the Oort Cloud ● 50,000 AUs from the sun ○ One AU is the distance between the Earth and the Sun, 93 million miles

● The boundary of the Heliosphere is 200 AU from the sun ○ This is the farthest that the solar winds will reach Kuiper Belt ● A diffuse band of icy objects ● Some are up to 1,200 km across ● Comets originate here ● Neptune is in the inner edge ○ Neptune’s orbit defines interplanetary space vs interstellar space Asteroids ● Small bodies of rock or metal orbiting the sun ● Planetesimals that were never part of a larger body ● Most occur in a belt between jupiter and mars ● Range in size ○ Up to 30km across ○ Millions >1km in diameter ○ Too small to be reshaped by gravity ● They can and have struck Earth Comets ● Icy objects that orbit the sun ● Highly elliptical orbits ● When approaching the sun, they form a large coma (tail) ○ Tail is comprised of evaporating gas and dust ○ Tail always points away from the sun ● Short-period comets originate in the Kuiper Belt ● Longer period comets come from the Oort Cloud ● Dirty “snowballs” made of ○ Dust ○ Organic compounds ○ H2O, CH4, NO3, CO2 ● Comets can strike Earth and bring water

Continental Drift -South America is moving west

Plate Tectonics: relatively new development in scientific thinking (1960s), has evolved and strengthened up to the present day, first scientist to work on it was Alfred Wegener

Alfred Wegener: German meteorologist and polar explorer, wrote The Origins of Ocean and Continents i n 1915, book was discounted because it lacked explanation and it was considered radical. People thought the oceans and continents were permanently fixed, and he could not explain how the continents moved Harry Hess: published his “Essay in Geopoetry” explaining seafloor spreading and other important evidence that was able to prove Alfred Wegener’s ideas Seafloor Spreading: Harry Hess proposed sea-floor spreading saying that as continents drift apart, new ocean floor forms between. Lithosphere: broken into ~15 plates that interact along their boundaries, move at a rate of 1 to 15 cm/year *The radius of the Earth is constant, which means the rate of formation = rate of destruction* Pangea: supercontinent that was over the ancient South Pole. Ohio was once covered by a shallow warm ocean because it was near the equator. Explains why there are identical fossils found on widely separated land and why distinctive rock assemblages with the same chemical composition, mineralogy, and age match across the Atlantic. Lystrosaurus: non swimming, land-dwelling reptile Cynognathus: non swimming, land-dwelling mammal-like reptile Mesosaurus: a freshwater reptile Glossopteris: a polar plant with heavy seeds Echo Sounding (sonar): allowed for rapid sea-floor mapping. Data was collected as ships travelled the ocean Oceanographers discovered that: (ocean floor) - Mid ocean mountain range ran through every ocean - Deep ocean trenches occur near volcanic island chains - Submarine volcanoes poke up from the ocean floor. - Huge fracture zones segment the mid-ocean ridge.

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Belts of concentrated subsea earthquakes were found, and they were limited to mid-ocean ridge axes and deep ocean trenches Sediment in sea-floor spreading thickens away from ridges Earthquakes at mid-ocean ridges indicate cracking As molten rock rises it cools and hardens into solid rock

Continents move apart as sea-floor spreading occurs, and continents move together as sea-floor is subducted Earth’s magnetic field: the flow in the liquid outer core creates the magnetic field. It sometimes flips rapidly Paleomagnetism: iron minerals archive the magnetic signal at formation. Hot magma = high temperature = no magnetization (atoms move around randomly). Cooled magma = low temperature = permanent magnetization (dipoles in minerals align with earth’s magnetic field and become frozen in alignment) The width of the magnetic anomaly stripes = speed of plate movement (or spreading) Faster spreading= wide stripes slower spreading= narrow stripes Magnetic reversals: layered lava flows reveal reversals in magnetic polarity. Reversals are geologically rapid and can be used as time markers. They give us the ability to explain magnetic anomaly stripes. Positive anomaly: sea-floor rock normal polarity Negative anomaly: sea-floor rock reversed polarity Magnetic anomalies: are symmetric across the MOR Sea-floor rocks worldwide have been sampled by drilling. The age increases with distance from MORs. The sediment thickens with distance for MORs. Earthquakes The biggest earthquakes are in subduction zones. Surface waves: limited to the surface of the Earth; they cause vertical motion of the surfaces and most of the structural damage due to earthquakes Seismograph: mass decoupled from the ground remains in place while the ground and the recording drum move during the passage of seismic waves, which are recovered on the seismograph.

New Madrid Fault Line: 150 mile fault, 200 quakes per year, last large earthquake in 1811-1812 (St. Louis and Memphis weren’t as large back then), 90% chance that magnitude 6-7 earthquake will occur in the next 50 years -Earthquakes have a focus (underground) which is directly below the epicenter of the earthquake -Even regions that have historically experienced relatively few earthquakes can become tectonically active Atoms and Ionic Bonds Element: substance composed of a single type of atom Atom: the smallest particle of an element that retains the properties of the element Ion: electrically charged atom Proton: positively charged Neutron: neutral charge (0) Electron: negative charge Common Cations: Silicon (Si^+4), Aluminum (Al^+3), Iron (Fe^+3), Calcium (Ca^+2), Potassium (K+), Sodium (Na+) Common Anions: Oxygen (O^-2) Si-O tetrahedron: bonds are formed through the interactions of electrons (gain/loss) between adjacent Mineral: naturally occuring, solid, inorganic or formed by process, specific chemical composition, specific crystal structure Silicate class: 95% of the earth are made of silicate minerals (SiO4)^4Igneous minerals: Feldspar, quartz, olivine, pyroxene, amphibole, mica (biotite, muscovite

Volcanoes and Subduction Zones -Most abundant components of magma: SiO2 -Shield volcanoes are in Hawaii Tectonic Plates: change shape and size throughout their history Plate Boundaries ● Divergent Boundaries ○ Tectonic plates move apart ○ Sea floor spreading causes plates to move apart ○ Magma wells up, cools and forms oceanic crust ○ Ocean basin expands in width ● Convergent Boundaries ○ Tectonic plates move together ○ The process of plate consumption is called subduction  ■ The subducting plate is always oceanic ■ Subduction recycles oceanic lithosphere ■ Subduction is balanced by sea floor spreading ■ Earth maintains a constant  circumference

■ The subducting plate descends at an average of 45 degrees ● Earthquakes deepen away from trenches ■ The lower mantle may be a “plate graveyard” ○ Also called convergent margin, subduction zone, trench ● Transform Boundaries ○ Tectonic plates move sideways ○ Plate material is neither created nor destroyed ○ Also called transform fault, transform Magma rises to the surface through a conduit (volcano) or a fissure (mid-ocean ridge) Definition of a Mineral ● Naturally occuring ● Solid ● Inorganic or formed by inorganic processes ● Specific chemical composition ● Specific crystalline structure Two types of Crust ● Oceanic ○ Thinner (5km) ○ More Aluminum and Iron (Al and Fe) ○ Denser ○ 70-75% Oceanic ● Continental ○ Thicker (35-65km) ○ More Silicon and Oxygen (Si and O) ○ 25-30% Continental Oceanic crust comes from Divergent Plate Boundaries 1 * 10e6 underwater volcanoes Shield Volcanoes are hotspots 1. Convection brings the magma to the surface of the ocean floor 2. Magma then cools to form basalt and gabbro a. Primarily mafic minerals plus some felsic minerals form Formation of Continental Crust ● Stratovolcanoes ○ Convergent plate boundary

1. Oceanic Crust subducts 2. Oceanic crust partially melts according to geothermal gradient and Bowen’s reaction series 3. Felsic magma rises to form volcano a. Granite and rhyolite Viscosity: Resistance to flow ● Low viscosity- flows easily; spreads out ● High viscosity- resists flow; remains close to source ○ Increasing temperature decreases viscosity ○ Composition- silica (SO2) content affects viscosity ■ More SO2 in magmas are more viscous...