Test 1 Study Guide
Test 1 Study Guide GEO 101-007
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This 78 page Study Guide was uploaded by Jennifer Gintovt on Wednesday September 9, 2015. The Study Guide belongs to GEO 101-007 at University of Alabama - Tuscaloosa taught by Dr. William Lambert in Summer 2015. Since its upload, it has received 181 views. For similar materials see The Dynamic Earth in Geology at University of Alabama - Tuscaloosa.
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GEO 101007 Notes 8192015 What is geology The study of the earth 0 Rocks sediments rivers oceans the atmosphere plants animals and how they interact with one another today and in the past Geology vs geological sciences Geologists must apply the knowledge and tools of many subjects What is science Science is the human effort to understand or to better understand the natural world and how it works by observing physical evidence Science is done through observation The application of science to geology Atmosphere Biosphere Hydrosphere Cryosphere Geosphere Layers of the earth Core most dense Mantle denser Crust least dense 0 Example of hardboiled egg The earth s interior Crust Upper mantle Lower mantle Outer core Inner core The Kola Superdeep Borehole Kola peninsula Russia Started drilling in 1970 Reached a maximum depth of 76 miles in 1989 Rock samples were collected Earths center is 6371 km Kola went 122 km which is O2 Xenoliths A rock fragment which becomes enveloped in a larger rock during the latter s larger rocks development and hardening Sometimes carried to earths surface GEO 101007 Notes 8192015 Continental vs Oceanic Crust Continental crust is much thicker than most oceanic crust Moho the boundary between the Earth s crust and mantle apanese Scientific Drilling Ship Chikyu 1000000000 project 0 we know more about the moon than we do what is a few miles below our feet Earthquakes tell us about the earth s interior Plate tectonics and Earthquakes the earths lithosphere crust upper mantle is divided into rigid plates of various sizes that move Plate Boundaries Divergent convergent and transform most earthquakes occur at plate boundaries where pates are moving in relation to one another Most volcanoes occur at plate boundaries due to interaction of plates with one another Magma vs Lava 0 Pretty much the same 0 Magma is in the ground Lava is at the earths surface Three types of rocks Igneous rocks basalt granite Sedimentary rocks limestone conglomerate Metamorphic rocks gneiss quartzite The Rock Cycle Illustrates the different processes and paths as earth materials change both on the surface and inside the earth GEO 101007 Notes 82415 Scientific Method Recognizing the Problem an observation without and obvious explanation Collecting data collecting clues that point to an answer to the recognized problem Proposing a hypothesis a possible explanation involving only naturally occurring process that can explain a set of observations Testing hypotheses putting the proposed hypotheses through a series of tests to see if the proposed explanation continues to explain the observations Theory scientific ideas explanations supported by an abundance of evidence they have passed many tests and have failed none Scientific law ideas that must be considered true based on everything we know of the natural Universe eg Newton s Law of Gravitation Humans are curious beings Over the past couple thousand years man has shifted from a philosophical view of the Earth and Universe to a view based on scientific principles using the scientific method Where does the Earth fit into the Universe Geocentric Model without moving while the Moon and the planets whirled around it within a globe of stars Heliocentric Model while the earth and other planets orbited around it The Renaissance and the Telescope Galileo Galilei only saw a very small part of the universe The Hubble Space Telescope 1990 James Webb Space Telescope October 2018 The Milky Way 300000000000 stars 100000 light years across 0 1 light year 6 trillion miles 100 billion galaxies today s technology Hubble May be 1000 billion galaxies or more Webb telescope Observations tell us Earth Sun Milky Way is not in the center of the Universe GEO 101007 Notes 82415 Everything is in motion Questions about the universe Is the universe getting bigger smaller or has it always been the same size Was there a beginning to the Universe or has it always been the same The Doppler Effect Movement of the source of soundwaves causes wave frequencywavelength to change thus changing the sound we hear Movement of the source of lightwaves causes wave frequencywavelength to change thus changing the color we see Applying the Doppler Effect to the Universe NASA took pictures of multiple galaxies The red color of the galaxies indicated that things are moving away from us meaning the universe is expanding If everything is expanding was all of it once together The Big Bang Theory Key Points The universe has a beginning The universe started infinitely smallhot Early universe what mainly hydrogen and helium The universe is old I 137 billion years old 0 Most but not all scientists agree on this basic model 0000 Nebula started to form As the Universe cooled clouds of gas nebula started to form and were mainly hydrogen 74 and helium 24 How many naturally occurring elements exist in nature 0 92 The Solar System and its Formation Nebular Theory Gravitation between materials in nebula puled mass inward When pulled inward spin increased in accord with the conservation of angular momentum think figure skater The spinning cloud conformed to the shape of a spinning disk 0 The center of the disk is the protosun 0 Away from the center planetesimals formed Planetesimals accreted more matter to become planets GEO 101007 Notes 82415 Key Terms Planet an object that orbits a star is spherical and has cleared its neighborhood of other objectsquot sorry Pluto o Terrestrial Planet Earth shell of rock around metallic iron alloy core 0 Gasice giant planet Mostly gas or ice very large Moon a sizeable body locked in orbit around a planet Asteroid chunks of rock and or metal large range in size Comets chunks of mostly ice with a path that sometimes approaches the Sun Early Earth Heat from collision and radioactive decay melted much of the earth Moon Formation Theory Small planet collides with Earth and produces a ring of debris around Earth that eventually becomes the moon A Cooling Earth With time and cooling the crust becomes solid volcanoes add gases to the atmosphere water condenses some water from comets 454 billion years later we end up with a blue planet The Habitable Zone or the Goldilocks Zone Earth is located at the perfect distance from the sun where it s not too hot or too cold to sustain life Solar Wind and Cosmic Rays from Supernovas 0 Plasma electrons protons and other charged particles that are harmful to life Earth s magnetic Field Basically a dipole has a north and a south Produced by Earth s geodynamo Melted iron moves within the outer core Magnetic field is constantly changing Protection From Solar Wind Magnetic field protects us from most but not all solar wind cosmic rays Aurorae Glow is due to trapped charged particles interacting with gas atoms in the upper atmosphere GEO 101007 Notes 82415 Earth s Thin Atmosphere 78 Nitrogen 21 Oxygen Other 1 argon carbon dioxide neon methane ozone carbon monoxide sulfur dioxide Density and Layers of Earth s Atmosphere As you move up in altitude the density of the air goes down along with the temperature Element Distribution SunStars mostly helium and hydrogen Earth s Atmosphere mostly nitrogen and oxygen Earth mostly iron oxygen silicon and magnesium 912 Categories of Earth Materials Minerals a solid natural not manmade substance in which atoms are arranged in an orderly pattern 0 Crystal 0 Grain Glass a solid in which atoms are not arranged in an orderly pattern cooled rapidly Rock an aggregate of mineral crystals or grains and masses of natural glass 0 Igneous o Sedimentary o Metamorphic Sediment loose mineral grains that are NOT stuck together Metal solids composed of metal atoms iron aluminum gold copper etc 0 Allow mixture of more than two different types Melt is formed when solid materials become hot and transform into liquid ex Molten rock Organic Compounds carboncontaining compounds that either occur in living organisms or have Silicate Minerals and Silicate Rocks Silica silicon oxygen compound Silicate minerals silica mixed with varying proportions of other elements iron and magnesium Silicate rocks composed of silicate minerals Most common minerals on earth GEO 101007 Notes Felsic Felsic Granite Earth s Interior 82415 Igneous Rock Silica Content Intermediate Ma c Ultrama c Four rocks we will discuss rst Intermediate Ma c Ultrama c 44 39 Gabbr Peridotite Crust granite gabbro basalt Upper mantle peridotite GEO 101007 Notes 82415 Geothermal gradient The rate of change increase in temperature with depth 0 Upper crust 15 to 50 degrees C per Kilometer 0 At greater depths 10 degrees C per Kilometer Tuscaloosa is approximately 79 km from Birmingham 0 At 79 km depth the temperature could be 1185 degrees C or greater The Earth s Core Temp may exceed 4700 degrees C Pressure may exceed 3600000 atm Crust Outer shell different chemistry than mantle 0 Continental crust relatively thick felsic granite relatively low density 0 Oceanic crust relatively thin mafic basalt gabbro relatively high density Moho Not a layer but the boundary between lower crust and upper mantle o Recognized by change in velocity of energy waves from earthquakes Mantle 2885 km thick largest part of Earth by volume one rock type peridotite upper and lower sections 0 Soft solid rock near the surface ows very slowly 15 cm per year 0 Small percentage is liquid Core Innermost section 0 Outer core liquid iron alloy due to high temperature 0 Inner core solid ironnickel alloy due to high pressure despite even higher temp o The nature of the core generates Earth s magnetic field The Earth s Interior Lithosphere all of crust plus upper mantle rigid Asthenosphere portion of mantle that can ow not liquid Thickness of lithosphere varies boundary is where temperature is 1280 degrees C rock becomes soft enough to ow GEO 101007 82515 Chapter 2 Important Terms Absolute plate velocity the movement of a plate relative to a fixed point in the mantle Abyssal plain a broad relatively at region of the ocean that lies at least 45 km below sea level Accretionary prism a wedgeshaped mass of sediment and rock scraped off the top of a downgoing plate and accreted onto the overriding plate at a convergent plate margin Active margin a continental margin that coincides with a plate boundary Apparent polarwander path a path on the globe along which a magnetic pole appears to have wandered over time in fact the continents drift while the magnetic pole stays firmly fixed Asthenosphere the layer of the mantle that lies between 100150 km and 350 km deep the asthenosphere is relatively soft and can ow when acted on by force Bathymetry variation in depth Black smoker the cloud of suspended minerals formed were hot water spews out of a vent along a midocean ridge the dissolved sulfide components of the hot water instantly precipitate when the water mixes with seawater and cools Chron the time interval between successive magnetic reversals Collision the process of two buoyant pieces of lithosphere converging and squashing together Continental drift continents have moved and are still moving slowly across the Earth s surface Continental rift a linear belt along which continental lithosphere stretches and pulls apart Continental shelf a broad shallowly submerged fringe of a continent oceanwater depth over the continental shelf is generally less than 200 meters the widest continental shelves occur over passive margins Convergent boundary A boundary at which two plates move toward each other so that one plate sinks subducts beneath the other only oceanic lithosphere can subduct GEO 101007 82515 Divergent boundary a boundary at which two lithosphere plates move apart from each other they are marked by midocean ridges Fracture zone a narrow band of vertical fractures in the ocean oor fracture zones lie roughly at right angles to a midocean ridge and the actively slipping part of a fracture zone is a transform fault Global positioning system A satellite system people can use to measure rates of movement of the Earth s crust relative to one another or simply to locate their position on the Earth s surface Hot spot a location at the base of the lithosphere at the top of a mantle plume where temperatures can cause melting Hotspot track a chain of nowdead volcanoes transported off the hot spot by the movement of a lithosphere plate Lithosphere the relatively rigid non owable outer 100 to 150kmthick layer of the Earth constituting the crust and the top part of the mantle Lithosphere plate one of may distinct pieces of the lithosphere Earth s relatively rigid shell that are separated from one another by breaks plate boundaries Magnetic anomaly the difference between the expected strength of the Earth s magnetic field at a certain locatiOon and the actual measured strength at the bottom of a magma chamber Magnetic declination the angle between the direction a compass needle points at a given location and the direction of true north Magnetic dipole an imaginary vector that points from the north magnetic pole to the south magnetic pole of a magnetic field Magnetic inclination the angle between a magnetic needle free to pivot on a horizontal axis and a horizontal plane parallel to the Earth s surface Magnetic pole the ends of a magnetic dipole all magnetic dipoles have a north pole and a south pole Magnetic reversal the change of the Earth s magnetic polarity when a reversal occurs the field ips from normal to reversed polarity or vice versa Mantle plume a column of very hot rock rising up through the mantle GEO 101007 82515 Marine magnetic anomaly the difference between the expected strength of the Earth s main dipole field at a certain location on the sea oor and the actual measured strength of the magnetic field at that location Midocean ridge a Zkmhigh submarine mountain belt that forms along a divergent oceanic plate boundary Paleopole the supposed position of the Earth s magnetic pole in the past with respect to a particular continent Pangaea a supercontinent that assembled at the end of the Paleozoic Era Passive margin a continental margin that is not a plate boundary Plate boundary the border between two adjacent lithosphere plates Plate tectonics the outer layer of the Earth the lithosphere consists of separate plates that move with respect to one another Relative plate velocity the movement of one lithosphere plate with respect to another Ridgepush force a process in which gravity causes the elevated lithosphere at a midocean ridge axis to push on the lithosphere that lies farther from the axis making it move away Rifting a divergent boundary forms when a continent splits and separates into two separate continents Sea oor spreading the gradual widening of an ocean basin as new oceanic crust forms at midocean ridge axis and then moves away from the axis Seamount an isolated submarine mountain Slabpull force the force that downgoing plates or slabs apply to oceanic lithosphere at a convergent margin Subduction the process by which one oceanic plate bends and sinks down into the asthenosphere beneath another plate Transform boundary a boundary at which one lithosphere plate slips laterally past another Trench a deep elongate trough bordering a volcanic arc a trench defines the trace of a convergent plate boundary GEO 101007 82515 Triple junction a point where three lithosphere plate boundaries intersect Volcanic arc a curving chain of active volcanoes formed adjacent to a convergent plate boundary WadatiBenioff zone a sloping band of seismicity defined by intermediate and deepfocus earthquakes that occur in the downgoing slab of a convergent plate boundary GEO 101007 Chapter 2 The Way the Earth Works Plate Tectonics Less than 100 years ago leading scientists thought the map of the world has always looked the same Alfred Wegener German meteorologist Artic climate scientist 18801930 50 years old Well known by fellow researchers of climate and the Earth Observations Wegener made 4 initial observations His work combined with that of other scientists has developed into what is now known as the Theory of Plate Tectonics Also known as the theory of continental drift 0 The fit of the continents Paleoclimate data The distribution of fossils Matching geologic rock units 000 Observation 1 The fit of the continents Wegener thought that it was not by change that the continents appeared to fit together like large puzzle pieces Originally a supercontinent called Pangaea o Glacial striations glacier picked up rocks that got stuck in the ice and scratched the surface of other rocks as the glacier moved I Southern Africa I Southern South America I Southern India I Southern Australia I Antarctica Areas where they are not present today Wegener concluded that the areas with glacial striations must have once been closer to the South Pole and these regions were once near each other 0 Swamps eventually form coal from buried plant material I There are strange coal deposit locations throughout the world ex Antarctica Observation 2 Paleoclimate Data Wagener concluded that evidence of past environments differing from the current environments meant the continents must have been at different latitudes in the past at different distances from the equator GEO 101007 Observation 3 Fossil Records Wegener concluded the observed fossil pattern demonstrated the continents must have once all been together Observation 4 Matching geological units Wagener concluded it was not coincidence that rock units matched across different continents now separated by vast oceans The Origin of Continents and Oceans Wegener 1915 His theory was highly criticized by fellow scientists What force could possibly be great enough to move such large masses as the continentsquot Wegener could not answer this question He died in Greenland and his theory lay dormant for 3 decades With time came more4 observations by other scientists Paleomagnetism Sea oor spreading Volcanoes earthquakes distribution Geographic vs Magnetic North Pole Magnetic Northquot moves with time This means a magnet would point slightly different directions in the past south pole moves too If a rock forms from magma today Tiny magnetic crystals in rock will align themselves with today s magnetic north as the liquid turns to a solid If you study this rock 1000 years from now you would have a record of where magnetic north was in 2015 Rocks quotlockquot in the magnetic north south With this concept in mind Today scientists can study magnetic crystals in old rocks millions of years old and discover the direction of magnetic northsouth What does WWII have to do with Geology Sonar used to map the ocean oor water depth topography of ocean lake oor Ocean oor surprises In some cases deep trenches near the shore GEO 101007 Ridges of mountains in the middle of the ocean Magnetic North Recorded in MidOcean Ridge Rock Tiny magnetic crystals those with iron pointed in very different directions some rocks showed north to the south Magnetic Reversals The oceanic rock revealed that there was a pattern of the magnetic northquot reversing polarity many times Age of Oceanic Rock Once technology allowed for rocks to be dated we found the youngest rock to be near midocean ridges Other Sea Floor Observations Ocean sediment was thinnest at midocean ridges and thickest at the ocean s edges Even the thickest sediment was too thin given the age of the Earth Even the oldest ocean crust was much much younger than the age of the Earth Oceanic crust has a very different chemistry than continental crust basalt vs granite respectively Harry Hess Sea Floor Spreading Magma would rise and form new oceanic crust and would push the old crust further out The old ocean oor sinks back into the mantle He thought that only the crust spread but this idea was incorrect Sea Floor Spreading and Magnetic Reversals new oceanic oor is created and old oor is separated and the polarity of the sediment created is based on the current polarity of the poles Pattern of Earthquakes Shows where rock movement occurs ex Plates moving Plate Tectonic Theory The Earth s surface lithosphere crust upper mantle consists of about 20 rigid quottectonicquot plates Tectonic plates move relative to one another Tectonic plate movement causes continents to drift Wegener was right Interactions at the plate boundaries result in earthquakes volcanoes and mountain building GEO 101007 Plate Boundaries on Maps Plates oat on soft Asthenosphere Relatively cold and rigid Plate Boundaries The inner area of a tectonic plate for the most part is rigid with little action so to speak Where two plates meet the plate boundaries is where the action occurs many geologic processes of interest There are three types of plate boundaries 0 The plate boundaries are defined by the type of relative movement between the two plates 0 Divergent plates move away from each other 0 Convergent plates move toward each other 0 Transform plates move along side the other Each type of plate boundaries has distinct geologic process Divergent Plate Boundary Two plates move way from each other Typically found in oceans Midocean ridge New young crust is formed Earthquakes occur Small volcanic eruptions Convergent Plate Boundary Two plates move toward each other More dense plate sinks under less dense plate One of the plates is consumed Earthquakes occur Large volcanic eruptions Transform Plate Boundary Two plates move toward each other More dense plate sinks under less dense plate One of the plates is consumed Earthquakes occur Large volcanic eruptions GEO 101007 Divergent Plate Boundary Eg Atlantic MidOcean Ridge Produce mafic rocks 0 Basalt gabbro Black Smoker Pillow Basalt Continental Rifting Normal land starts to pull apart Eventually molten rock can rise through the split Eventually new land or ocean can form 0 Eg East African Rift Valley Convergent Plate Boundary Three types of collisions o Oceanic Continental plates 0 Oceanic Oceanic plates 0 Continental Continental plates Oceanic Continental 0 Forms island arc o Felsic rocks 0 Eg Andes Mts South America Chile earthquake and tsunami prone Oceanic Oceanic 0 Forms island arc o Felsic rock 0 Eg Aleutian Island Arc Alaska volcanoes Continental Continental 0 Forms mountain range 0 Metamorphic rocks 0 Eg Himalayan Mountains Nepal Transform Plate Boundary Eg San Andres Fault California no rock formation Plate movement Rates Additional Topics of Interest Continental Margin land ocean boundary 0 Passive 0 Active Hot spotslike a conveyor belt for making new islands if in the ocean Eg Hawaii Yellowstone GEO 101007 Triple junction where 3 different plates combine together Tectonic Plates move but how Convection driven this theory is no longer accepted by most scientists Ridge push force force that drives plates away from a mid ocean ridge Slab pull force the force downgoing plates or slabs apply to oceanic lithosphere at a convergent margin GEO 101007 82815 GEO 101007 Chapter 1 Key Terms Alloy a metal containing more than one type of metal atom Asthenosphere a layer of gases that surrounds a planet Atmosphere the layer of the mantle that lies between 100150 km and 350 km deep the asthenosphere is relatively soft and can ow when acted on by force Bathymetry variation in depth Big Bang Theory a cataclysmic explosion that scientists suggest represents the formation of the Universe before this event all matter and all energy were packed into one volumeless point Core the dense iron rich center of the Earth Cosmology the study of the overall structure of the Universe Crust the rock that makes up the outermost layer of the Earth Differentiation a process early in the planet s history during which dense iron alloy melted and sank downward to form the core leaving lessdense mantle behind Dipole a magnetic field with a north and South Pole like that of a bar magnet Doppler Effect the phenomenon in which the frequency of wave energy appears to change when a moving source of wave energy passes an observer Earthguake a vibration caused by the sudden breaking or frictional sliding of rock in the Earth Earth System the global interconnecting web of physical and biological phenomena involving the solid Earth the hydrosphere and the atmosphere Energy the capacity to do work Expanding Universe Theory the theory that the whole Universe must be expanding because galaxies in every direction seem to be moving away from us Fission a nuclear reaction during which the nucleus of a large atom splits to form two nuclei of smaller atoms the process also releases neutrons and energy Frequency the number of waves that pass a point in a given time interval GEO 101007 82815 Fusion a type of nuclear reaction during which the nuclei collide and bond fusion occurs in stars and hydrogen bombs Galaxy an immense system of hundreds of billions of stars Geocentric Model an ancient Greek idea suggesting that the Earth sat motionless in the center of the Universe while stars and other planets and the Sun orbited around it Geothermal Gradient the rate of change in temperature with depth Giant Planet the four outer or Iovian planets of our Solar System which are significantly larger than the rest of the planets and consist largely of gas and or ice Gravity the attractive force that one mass exerts on another the magnitude depends on the size of the objects and the distance between them Heliocentric Model an idea proposed by Greek philosophers around 250 BCE suggesting that all heavenly objects including the Earth orbited the Sun Lithosphere the relatively rigid non owable outer lOOto 150kmthick layer of the Earth consisting of the crust and the top part of the mantle Lower Mantle the deepest section of he mantle stretching from 670 km down to the coremantle boundary Magnetic Field the region affected by the force emanating from a magnet Mantle the thick layer of rock below the Earth s crust and above the core Melt molten liquid rock Metal a solid composed almost entirely of atoms of metallic elements it is generally opaque shiny smooth malleable and can conduct electricity Meteor a streak of bright glowing gas created as a meteoroid vaporizes in the atmosphere due to friction Meteorite a piece of rock or metal alloy that fell from space and landed on Earth Mineral a homogenous naturally occurring solid inorganic substance with a definable chemical composition and an internal structure characterized by an orderly arrangement of atoms ions or molecules in a lattice Most minerals are inorganic GEO 101007 82815 Moho the seismicvelocity discontinuity that defines the boundary between the Earth s crust and mantle Named for Andrija Mohorovicic39 Moon a sizable solid body locked in orbit around a planet Nebula a cloud of gas or dust in space Nebular Theory the concept that planets grow out of rings of gas dust and ice surrounding a newborn star Planet an object that orbits a star is roughly spherical and has cleared its neighborhood of other objects Planetesimal tiny solid pieces of rock and metal that collect in a planetary nebula and eventually accumulate to form a planet Protoplanetary Disk the area around a newly formed star that contains material that did not become part of the star but can eventually be used in the formation of planets moons asteroids and comets Protoplanet a body that grows by the accumulation of planetesimals but has not yet become big enough to be called a planet Protostar a dense body of gas that is collapsing inward because of gravitational forces and that may eventually become a star Radioactive Element atoms that spontaneously undergo fission Red Shift the phenomenon in which a source of light moving away from you very rapidly shifts to a lower frequency that is toward the red end of the spectrum Refractory Materials substances that have a relatively high melting point and tend to exist in solid form Sediment an accumulation of loose mineral grains such as boulders pebbles sand silt or mud that are not cemented together Silica SiOz Solar System our Sun and all the materials that orbit it including planets moons asteroids Kuiper Belt objects and Oort Cloud objects Star an object in the Universe in which fusion reactions occur pervasively producing vast amounts of energy our Sun is a star GEO 101007 82815 Stellar Nucleosysthensis the production of new larger atoms by fusion reactions in stars the process generates more massive elements that were not produced by the Big Bang Stellar Wind the stream of atoms emitted from a star into space Supernova a shortlived very bright object in space that results from the cataclysmic explosion marking the death of a very large star the explosion ejects large quantities of matter into space to form new nebulae Terrestrial Planet planets that are of comparable size and character to the Earth and consist of a metallic core surrounded by a rock mantle Transition Zone the middle portion of the mantle from 400 to 670 km deep in which there are several jumps in seismic velocity Universe all of space and all the matter and energy within it Upper Mantle the uppermost section of the mantle reaching down to a depth of 400 km Volatile elements or compounds such as H20 and C02 that evaporate at relatively low temperatures and can exist in gaseous forms at the Earth s surface Wave a disturbance that transmits energy from one point to another in the form of periodic motions Wavelength the horizontal difference between two adjacent wave troughs or two adjacent crests Chapter 3 Minerals CHAPTER Patterns Name a 39 Mineralg f Cave of the Crystals gypsum Chihuahua Mexico m136 grenheit largest crystal 12 m 39 ft by 4 In 13 ft Geo f phlcSpeleo Goals for today s lecture To learn the geologic de nition of a mineral To have a better understanding of how minerals are classi ed and how to identify them To learn a few of the uses for minerals Basic chemistry refresher Chemistry Basics Element a substance that is made up of only one type of atom Atom smallest piece of element that retains the characteristics of that element Are made up of protons neutrons and electrons Neutral Carbon Atom except hydrogen 1P 1E ON Nucleus Proton positive charge Electron negative charge protons O Neutrons 0 Electrons Chemistry Basics Atomic number The number of protons in an atom An element is de ned by the number of protons Atomic weight The number or protons plus neutrons in an atom carbon 6P6N 12 Electrons have very little mass Atomic weight Chemistry Basics 1amp1 at atom with an unequal number of protons to electrons Cation positively charged ion has more protons than electrons Anion negatively charged ion has more electrons than protons 1 electron gained CL atom with 17 protons and 17 neutrons CL39 ion with 18 electrons and 17 protons anion Sodium atom 39 Sodium ion 11 protons 11 protons 11 electrons 1O electrons Chemistry Basics Metals Nonmetals and Metalloids metalloids Chemistry Basics Chemical bond an attractive force that holds two or more atoms together Strength of bond varies think glue that holds atoms together l Ionic 2 Covalent 3 Metallic 4 Van Der Waals force Chemistry Basics Chemical Bonds 1 Ionic bond Metal atoms give electrons to nonmetal atoms resulting in oppositely charged atoms ions that bond stick together opposites attract You Tube Somewhat weak bond in solids httpy0utuobeQf078thpC Transfer of electron Na Cl gt Na Cl Na Cl Na Cl Sodium atom Chlorine atom Sodium ion Chloride ion Sodium chloride NaCl Chemistry Basics Chemical Bonds 2 Covalent bond Nonmetal atoms that share electrons and are hence bonded together Strong bonds You httpyoutube7DjsD7Hcd9U Shared pair of electrons quot quotE r 1 i quot ii Iquot i quot I n I C r I l quot I Chemistry Basics 3 Metallic bonds Electrons form sea around positively charged atomic nuclei electrons move freely Good conductivity Ductile Malleable Strong bond You httpyoutubeer3TpaQ2A 0 w Metal Ion 0 Electron Copyright 200 Pearson qucation InC publishing as Pearson AddisonWesley Chemistry Basics 4 van der Waals force the relatively weak attractive forces that act on neutral atoms and molecules and that arise because of the electric polarization induced in each of the particles by the presence of other particles Carbon akxns Very weak attraction 39 quot i I I I39 l 5 f 5 O 0 quot 3 i o o 39 i s 2 39 39 L I s 39 39 s r s s gt Covalent j 39 a bonds 1 ir ixrs39f 1 r 1 vr 339 ghl 1 5quot L39 uhn W H d blt w I39r All rghh run um httpyoutube8qupvapO4 Chemistry Basics Chemical formula An expression which states the number and type of atoms present in a molecule of a substance H20 2 hydrogen atoms and 1 oxygen atom WATER MOLECULE Chemistry Basics Molecule two or more atoms bonded together the atoms can be the same or different Compound Two or more different WATER elements bonded together MOLECULE All compounds are molecules but not all molecules are compounds 1 IS a minera What 8 A R E m M C39391 V439 u 41 39 Over 4900 known minerals What is a mineral A mineral is a naturally occurring solid formed by geologic processes that has a crystalline structure and a de nable chemical composition Most minerals are inorganic not formed by plants animals The precise de nition is up for debate but this is What you need to know for this course Minerals are Naturally Occurring made by geologic processes Cut neral mineral fiXed Shape fixed Volu me I be squashed Minerals have a Crystalline Structure 3 THIS quartz crystal contains an orderly arrangement of atoms The arrangerr uem reserrrbles Scaffolding I b Atoms in nonerystalline solids such as gle Obsidian geologycom Minerals have a Crystalline Structure The organization of atoms has a pattern crystal lattice FIGURE 35 The nature of crystalline structure in minerals 1 Halite Naquot table salt 1 J J v 3 J J Chemical y bond vr J i i J I J 139 Ion J a In a hallanr lstiek model of halite b This hall model gives a the balls are ions and the sticks are better sense of how ions chemical bonds pack together in crystal Mineral chemistry can be described With a chemical formula Some chemical formulas are simple NaCl 1 sodium atom per 1 chlorine atom FIGURE 35 The nature of crystalline structure in minerals U Halite Mi table salt 1 J J v 3 J J Chemical y bond vr J i i J I J 139 Ion J a In a hallanr lstick morlel of halite b This hall model gives a the balls are ions and the sticks are better sense of how ions chemical bonds pack together in crystal Mineral chemistry can be described With a chemical formula Some chemical formulas are complex KMgFe3AlSi310FH2 geologycom Most not all minerals are inorganic Out of 49OO minerals only 31 minerals are related to organic processes fquot I l yv U 39 1 7 af x sunss v i Mineral Crystals Internal crystal structure dictates shape of unobstructed crystal llalitc Diamond Staumlitc Quartz Garnet Stilmitc Calcite lx39yanite b Crystals come in a variety of shapes including cubes prisms blades and pyrarrtitls Some teirr iinate at a point and some terminate with flat surfaces Polymorph Minerals With the same chemical composition but different crystal structures lJaeron atoms 5 Inn hands Example Diamond and Graphite carbon Cl 39lt 1 mm 39l39i r 1quot 1 h39l 139 39 I7 ml IN 392 Y39a39 til I im 39 39 Polymorph Minerals with the same chemical composition but different crystal structures Example Calcite and Aragonite CaCC3 Calcite Aragonite Minerals display patterns and symmetry FIGURE 36 initiate mei quotr 39rquot539l m m I39 i i L 3 s it SnmeHu h Mineral Crystals form in 5 ways Solidifrcation of a melt water freezing ice Precipitation from a solution salt halite crystals forming When salt water evaporates Solidstate diffusion atoms or ions migrate through a solid to form new crystal garnet Biomineralization oyster makes a shell Precipitation directly from a gas sulfur in volcanic areas Anhedral grains VS Eu ral crystals lune Minerals can be destroyed by melting dissolving or some other chemical reaction Acid Rain How do we identify minerals K3 39 Examination of physical properties to identify minerals Color Streak Luster Hardness Speci c gravity Crystal habit form Cleavage Fracture Special properties FDPONQW P NE Diagnostic Properties 1 Color I Generally unreliable for mineral identi cation variable due to impurities in mineral chemistry I Colorations of minerals produce gemstones Quartz 02 a Colo39 is tl39agnostrg of some mi elals but not ail l m exan uple quartz can mime m many colm s Diagnostic Properties 2 Streak 39 Color of a mineral in its powdered form I Obtained by scratching p the mineral on an lil llg f w porcelain plate i 39 39 Can be different from color because in powder form the effect of impurities is reduced b Tr lI iquotr he areal 1 i r1quot1quotdquotrl 39lJIT 39cziquotlt4 l39m I WTquot97 Equot I Elf quot t FTP Til quotIT S FTC Fquot m WCr33 H3M a39r39l W informative that mineral color Diagnostic Properties 3 Luster I The way a mineral scatters light I 2 maj or categories Nonmetallic silky glassy satiny Metallic lOOkS metal resinous9 pearly earthy Plagioclase feldspar Potassium feldspar I V39 0 39 i u c Pv iie 11L Iquot 2 Ill 5 L g iLe l ItT r ismr was aI 139quotTultf1alitILSTm39 Diagnostic Properties 4 Hardness Resistance of a mineral to abrasion or scratching All minerals are compared to a standard scale called the Mohs Hardness scale Very useful for mineral identi cation A I L nuts ul actual hardness kg11mm 7 000 6000 5 000 l000 3000 30le 1000 1 Mulls I l 0 9 8 T J O Q Q U T NN39vJCAJB39JW T Calcite Gypsum Talc Fluorite llialtmml Mineral r Suhxtumr Diamond Iorundum ruby 39l npu Quartz Sfr tquot fllr Orthoclase Iifeldspar b39tc39t39l kni 3391th pllitt39 lilllnl ilt Tapper pmm39 Calcite lingmmil Gypsum 39l alc Corundum l npu Apatite Quart rl lmt ldsv 1 I I Q 4 5 6 7 8 ll 39lll numlur Diagnostic Properties 5 Speci c Gravity I Weight of mineral divided by the weight of an equal volume of water I How heavy it feels Galena PbS ore of lead Tale Mg3Si410H2 baby powder Diagnostic Properties 6 Crystal Habit Form External expression of mineral s internal structure how atoms are arranged tetragonai monoclinic triclinic 39 v I I I O quot 11 quot39 0 l l I Xquot I quot Iquot hexagonal J orthorhombic 1 al 39 V 39 I s Iquot c O Oquot I i o39 ii 39 i I O quot 39 i I v l39 39139 ll 39 quot 39I I l 390 Z1 xquot examples examples examples examples examples examples t L quot39 halite zircon quartz sulfur mica feldspar galena chalcopyrite calcite staurollte gypsum rhnmmre Diagnostic Properties 7 Cleavage I Tendency to break along planes of weak bonding I Produces at shiny surfaces Examples of cleavage in calcite Number of Illustration of Examples of 2 not at 90 I cleavage j f directions 3 not at 90 Copyright 2005 Pearson Prentice Hall Inc Diagnostic Properties racture I Absence of cleavage When a mineral is broken Conchoidal Fracture U 39A Homo ago Copyrxgm Ir quot 200 1 PfC niICC Hail Inc I39dII I unmit If I I lmnr 2nd l ditiun HIIHIQHI It i m39un A nmwm Diagnostic Properties 9 Other Properties Magnetism iiilt2 f magnetite A e v l I Reaction to i i i i f hydrochloric acid calcite dolomite I Double refraction calcite I Taste halite I Smell sulfur rotten eggs For Example Quartz Color colorless Streak White Luster glassy Cleavage indistinct Fracture conchoidal Speci c Gravity 265 gcm3 Hardness 7 O SJ 39gtP t Mineral Groups Silicates 95 of continental crust Oxides Sul des Halides Carbonates Native rnetals Mineral Groups I Silicates SiOZ I Most important mineral group I Very abundant due to large percentage of silicon and oxygen in the Earth s crust I Siliconoxygen Tetrahedron fundamental building block I Four oxygen ions surrounding a smaller silicon ion Figure 1 Three ways of drawingthe silica tetrahedron a At left a ball amp stick model showingthe silicon cation in orange surrounded by4 oxygen anions in blue b At center a space filling model c At right a geometric shorthand Tetrahedral Forms I By combining the SiO2 tetrahedra together in different ways we can make different minerals Isolated tetrahedral fag olivine garnet Categories of Silicate SiOZ Minerals l Ma c I Simpler SiC2 structure lDark colored more dense I Contain iron and magnesium l Felsic lMore complex SiC2 structure lLight colored less dense lNo iron or magnesium Examples of Ma a Minerals Biotite wqwxvmjt HI 2029 all how r14 Itvcmende 5 quot Am hibole Example Felsic Minerals lt 2cm Feldspar Muscovite Uses for minerals Quartz Uses for minerals diamond ses for minerals Gypsum plaster of Paris Upcoming Test Wednesday September 9th 2015 Scantron Bring 2 pencil Exam 1 Multiple Choice TrueFalse Diagrams Prelude Chapters 1 2 3 plus Lecture PowerPoints Missed exams With a grade resulting in a zero cannot be dropped Place on table as you leave Your name printed The date Your name signed Something you learned in lecture today related to geology GEO 101007 83015 GEO 101007 Chapter 3 Key Terms Carbonate rocks containing calcite and or dolomite Cleavage 1 the tendency of a mineral to break along preferred planes 2 a type of foliation in lowgrade metamorphic rock Color the characteristic of a mineral due to the spectrum of light emitted or re ected by the material as perceived by eyes or instruments Conchoidal Fracture smoothly curving clamshellshaped surfaces along which materials with no cleavage planes tend to break Crystal a single continuous piece of a mineral bounded by at surfaces that formed naturally as the mineral grew Crystal Face the at surfaces of a crystal formed during the crystal s growth Crystal Habit the general shape of a crystal or cluster of crystals that grew unimpeded Crystal Structure the arrangement of atoms in a crystal Facet of a gem the ground and polished surface of a gem produced by a gem cutter using a grinding lap Gem a finished cut and polished gemstone ready to be set in jewelry Geode a cavity in which euhedral crystals precipitate out of water solutions passing through a rock Glass a solid in which atoms are not arranged in an orderly pattern Hardness of a mineral a measure of the relative ability of a mineral to resist scratching it represents the resistance of bonds in the crystal structure from being broken Luster the way a mineral surface scatters light Mineral a homogenous naturally occurring solid inorganic substance with a definable chemical composition and an internal structure characterized by an orderly arrangement of atoms ions or molecules in a lattice MOST minerals are inorganic Mineralogy the study of minerals GEO 101007 83015 Mohs Hardness Scale a list of 10 minerals in a sequence of relative hardness with which other minerals can be compared Polymorph two minerals that have the same chemical composition but a different crystal lattice structure Silicate silicate minerals minerals built from siliconoxygen tetrahedra arranged in chains sheets or 3D networks they make up most of the Earth s crust and mantle Siliconoxygen tetrahedron the Si04394 anionic group in which four oxygen atoms surround a single silicon atom thereby defining the corners of a tetrahedron Specific Gravity a number representing the density of a mineral as specified by the ratio between the weight of a volume of the mineral and the weight of an equal volume of water Streak the color of the powder produced by pulverizing a mineral on an unglazed ceramic plate
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