Geo Lec MidTerm 1

  1. What is a theory?
    tested and confimred hypothsis, complex and accepted fact
  2. What is sonar>
    WWII bounce sound waves to the ocean floor.
  3. What is Quartz?
    most abumdant on earths surface
  4. Describe the layers of the earth?
    • Crust: shell fractured brittle; mantle: mushy solid (silly putty); Outer Core: liquid metal; Inner Core; solid metal
    • Asthenophere: silly putty squishy liquid
  5. What is a law?
    it is a universal statemnt of fact, often written as a math equation; 10 to the 0 = 1, 10 to the 1 = 1. 10 to 2 = 100
  6. What is the scientific method?
    1. make an obersvation or identify problems. 2. make hypothesis to explain observations, make prediction based on hypothsis, 3. gather evidence to test the hypothsis. 4. reject hypotheis (ideally all but one).... Remaining hypothesis is the most probable.
  7. What is a hypotheis??
    untested explanation, educated guess
  8. untested explanation, educated guess
    1930 German meteorologist. proposed continents were not fixed and they were once fit together called Pangaea.
  9. Continental Drift
    Pangaea fragmented into peices into separate continents that drift apart.
  10. Sea Floor Spreading
    When continents drift apart, new ocean floor forms between them
  11. Seduction
    Continents move toward each other when the old ocean floor between them sinks back down into the Earth's interior
  12. Plates
    The earths lithosphere consists of 20 different pieces that slowly move relative to each other.
  13. The earths lithosphere consists of 20 different pieces that slowly move relative to each other.
    The grand unifying theory of geology, because it successfully explains great many geologic phenomena. It is the theory the plates move relative to each other.
  14. Paleomagnatism
    a record of earths magnetic field in the past. This provided proof of continental drift and contributed to the plate techtonic theory.
  15. Earths Magnetic Field
    Circulation of liquid iron alloy in the outer core of the earth generate a magnetic field. Two ends with opposite polarities.
  16. Magnetic Dipole
    an imaginary arrow that intersets the surface of the planet at two points known as the magnetic poles.
  17. How does Palemagnetism develop?
    One process happens when lava (molten rock) cools to form basalt. As it cools and solidifies, time magnetite crystals begin to grow. At first thermal energy causes the magnetic dipole to go crazy and then they settle to permanent parallelism with the Earths magnetic field.
  18. Apparent Polar-wander path
    The successive positions of dated paleopoles trace out a curving line. the continents move relative to a fixed pole. The continents must move with respect to each other. This proved Wegeners was theory of continental drift was correct.
  19. Mid-ocean ridges
    Divergent: The floor beneath all major oceans includes abyssal plains (broad, flat regions in the ocean), mid-ocean ridges (elogate submarine mountain ranges). The crest of the MOR's are the ridge axis. All MOR's are symetrical. Bathymetry is a mirror image on the other side.
  20. Harry Hess and his 'Essay in Geopoetry'
    late 1950 Hess suggest the seafloor had molten rock below it at the ocean ridges which furthered the idea of plate techtonics
  21. What is the outer part of the Eath in two layers?
    Lithosphere: crust plus the top plus the cooler top of the upper mantle.
  22. What is the difference between the continental and oceanic lithosphere?
    Their thickness. On average, continental lith has a thickness of 150km. The crustal part of the continental is lower in density. The crustal part of the oceanic lith is on 7-10 km and is highly dense mafic rock
  23. What are the basic principles of plate techtonics?
    The earths lithosphere is divided into plates that move relative to each other and relative to the underlying asthenosphere. Plate movement occurs 1-15cm a yr. The rocks along the plate boundaries undergo deformation as the plate moves away or into its neighbor. The earth surface constantly changes.
  24. What are divergent plate boundaries and sea floor spreading?
    2 oceanic plates move apart by the process of sea floor spreading. When the plates move apart, new floor forms. Takes place a submarine mountian range called a mid ocean ridge that rises 2 km above the adjecent abyssal plains of the ocean..
  25. Divergent Boundary
    Mid-Ocean Ridge MORS MOVING AWAY
  26. What are the evidence of plate techtonics?
    magnemitet rocks will aligh with magnetic field; paleomagnatism; polar wander; apparent polar wonder; continental drift;
  27. Who is Harry Hess?
    in the navy hypothesised that heat flow at ridge (magma implies new crust moved up at MOR), sediment depth confirms MOR is younger. Theory for sea floor spreading came up with sebduction
  28. What is the sinking process of one plate?
    What is the sinking process of one plate?
  29. What is the sinking process of one plate?
    Oceanic lithosphere is denser that sthenopsphere and can sink through the asthensphere.
  30. Can continental crust subduct?
    No, it is too bouyant. the low density rocks acts as a preserver not allowing it to sink
  31. What is the Wadati-Benioff Zone?
    THe belt of the earthquakes in a downgoing plate.
  32. THe belt of the earthquakes in a downgoing plate.
    an oceanic boundary, an oceanic plate sinks into the mantle beneath the edge of another plate. This process allows the two plates to move toward wach other and ocean basins to close. Trenches and volcanic arcs delinineate convergent boundaries.
  33. What is the transform boundary?
    A boundary at which on lithoisphere plate slips laterally past another. A vertical fault on which the slip direction parallels the earths surface.
  34. What is a mantle plume?
    a column of very hot rock rising up through the mantle to the base of the lithosphere.
  35. What is a chain of extinct volcanos?
    A hotspot track. When the overlying plate moves, it slowly carries the volcano off the top of the plume.
  36. Are hotspots oceanic bound or continental bound?
    Both, ex. Hawaiian Island and Yellowstone national park
  37. What is a collision?
    the process during which two buoyant pieces of lithosphere converge and squeeze together. Ex Himalayas and the Alps, India running into Asia.
  38. What is a continental rift?
    a linear belt in which continental lithosphere undergoes rifting or pulls apart. The lithosphere stretches horizontally so it thins vertically.
  39. What drives plate movement?
    What drives plate movement?
  40. What is ridge-push force?
    the force that drives plates away from a mor. it is caused by the fact that the ridge is elevated relative to the regions of oceanic plate away from the ridge.
  41. What is Slab-Pull Force?
    The force that downgoing plates (or slabs) apply to oceanic lithosphere at a convergent margin. Stanton def: cold dense rock working its way back to earth, pulls rock behind it.
  42. What are the earths layers?
    crust, mantle, outer core: liquid metal; inner core; solid metal
  43. What is convection?
    density driven vertical or cyclical movement of material in response to heat.
  44. Magnetic Reversals
    A various times during Earths history the polarity reversed. It alternates between normal polarity and sometimes it is revered polarity.
  45. What is a mineral?
    Homogeneneous, naturally occuring, solid, definable chemical composition, crystal lattuce.
  46. What is homogeneneous?
    the same chemical composotion throughout
  47. Crystal lattuce
    orderly; atoms or molecules oxygen in a pyramid = techagyron, sheet, piling on (glass not mineral)
  48. What is a crystal?
    crystal is the structure; mineral is the material;it extends in three directions; break crystal and you get a mineral.
  49. How do you get crystals to grow?
    3 ways: crystallization/freezing; preceptitation from ions in water disolved state to solid state (PPT); solid under higher temps (rock burial);
  50. How can you tell one mineral from another?
    Shape and color
  51. Streak
    refers to the color of a powder produced by pulverizing the mineral. scraping it on an unglazed ceramic plate
  52. Luster
    how mineral reflects light, metallic, looks like metal; mom-metallic - glassy, waxy pearl earthy
  53. Hardness
    measure of the relative ability of a mineral to resist scration. The atoms of a strong mineral are more tightly bound than a soft mineral. Diamond is the hardest mineral out there. Minerals are listed in a hardness of 1 to 10 via Friedrich Mohs.
  54. Mohs hardness scale
    listed 1 to10 10can scratch all materials.
  55. Crystallization seed
    crystals grow from seed. grow out from center, stop growing at barriers. Shape controlded by shape of barrier
  56. Specific Gravity
    • represents the density of the mineral to the weight of water.
    • Weight of volume of mineral OVER weight of volume of water. < > more or less dense that water. Density of mineral compared to the density of water. Water density is 1.
  57. Tetrahedron
    most silicate minerals in the crust consist of a building block which is the silicane oxygen tetrahedron. The basic building blocks of silicates.
  58. What are the mineral classes?
    Silicates, carbonates, native metals, oxides, Sulfur bearing, halides
  59. Define the Rock Cycles?
    sedimentary rock - erosian, metamorphic, heat pressure; igneous-melt
  60. How do you classify ifneous rocks?
    texture and mineral composition
  61. What are the rates of cooling crystal size?
    granite=slowcooling-large crystal; ryolite=fast cooling= small crystals, obsidian=very fast cooling=glass (no crystals, glass mising a latuce structure.
  62. Crystal Form
    measure of the angles of two adjecscent faces on crystal. 120 degrees is always a quartz
  63. Crystal Habit
    A general shape or growth; referest to the shape ofa single crystal with well-formed crystal faces. or to the character of an aggregate of many well formed crystals that grew together as a group. Catergories: needle like, columar radiating, primatic, fiberous, cubic
  64. what is cleavage
    if a mineral breaks to form distinct planar surfaces that have a specific orientation in relation to the crystal structure. it has a cleavage plane
  65. Frature and cleavage
    Different minerals frature in different ways. Depending on the internal arrangement of the atoms
  66. What is a conchoidal fracture?
    Materials that have no cleavage at all
  67. Silicates
    Most abundant at surface. silica tetrahedron, SIO4; 90% of continental crust; Quartz is most abundant silicate. Silicate= quartz, talc, opal, mica, beryl, feldsbar
  68. Carbonates
    Electrical charge, likes to attach to other minerals; wil FIZZ, DOUBLE VISION; Carbonate ion;
  69. Native Metals
    consist of pure masses of a single metal. Copper and gold.platinum
  70. Oxides
    Mixed with iron and oxygen; RUST OXIDATION; cobtain hematite and magnetite
  71. Sulfur Bearing minerals
    metals bonded to sulfur; gypsum/walllboard; gelena/pyrite Foolsgold; epsonite/Epson Salts.
  72. Halides
    Contains anything chloride, flourine, iodine = florite, italite (tablesalt)
  73. How is magma formed?
    if the pressure affecting hot mantle decreases while the temperature remains unchange, magma forms; magma also forms at locations where chemicals called colatiles mix with hot mantle rock. the rock mets or flux melting; melting as a result of heat transfer of rising magma forms magma
  74. What are the major types of magma?
    Felsic (or silicic), intermediate, Mafic, Ultramafic
  75. What is magma made of?
    Contains silicon and oxyfen, which bonds to form the silicon-oxygen tetrahedron. it contains other elements too.
  76. What are the factors that cocntrol magma's composition?
    Different rock sources; partial melting; magma mixing; assimilation or cross contamination
  77. What are the two reasons magma rises?
    first, magma rises because it is less dense then surrounding rock; second the weigh of over lying rock creates pressure at depth that squeezes magma upward
  78. Intrusive igneous rock
    rock formed by the freezing of magma underground
  79. extrusive igneous rock
    Rock that is formed by magma above ground, after it flows or explodes out (extrudes) onto the surface and comes into contact with the atmosphere or ocean
  80. What are the textures of igneous rocks?
    Fine grained - aphanitic; coarse grained - phanetic; porphyritic - two crystal sizes (chocolate cookie looking); glassy
  81. What are the Bowen Reaction Series?
    1920s Norman L. Bowen, began a series of experiements to determine how silicate minerals crystalize from melt. He created a diagram of order in which minerals freeze.
  82. What is fractional crystalization?
    the process by which a magma becomes progressively more silicic as it cools, because early-formed crystals settle out.
  83. What is the scheme for classifying the pricipal types of crystalline igneous rocks?
    the different compositional classes are distinguished on the basis of silica content- ultramafic, mafic, intermediate or felsic. The different textural classes are based coarse or fine. Color
  84. What is Ultra Mafic?
    CREATED AT MANTLE/HOTSPOT; DENSE; almost all dark; little silica; first to crystalize; high temps; Peridotite and olivine
  85. What is Mafic or Basltic Rocks?
    CREATED AT OCEANIC-CONTINENTAL; convergent plate boundary; less dense; made of oceanic lithosphere; dark in color, not a lot of green and grey; High in FE/mg; GABBRO/BASALT
  86. What is Intermidiate?
    COMBO of madic and felsic, happens at MOR's; Convergent plate boundary; less dense, MOUNTIAN RANGES; OCEANIC CONTINENTAL locations; mid gray (salt & pepper); DIORITE?ANDESITE
  87. What is Felsic rocks?
    CONTINENTAL RIFTS; CONTINENTAL LITHOSPHERE; divergent plate boundaries; silicates, lover in mg/fe; light in color (grey or pnk) ; granite/rhyolite
  88. What are pyroclastic rocks?
    Fragmental rocks composed of debris that have been blasted out of a volcano or thrown out in a fountain. Pyro meaning fire in greek.
  89. What are bombs?
    large rounded cone. cools in mid air.
  90. What is pumice?
    glassy; floats
  91. What are cinders?
    parcles that explide violently out of volcanoes.
  92. What is ash?
    erups violently out of volcanos.
  93. What is decompression?
    decrease in pressure; hot rock rises, lower in pressure; melting occurs. Temperature unchanged.
  94. Addition of volitiles
    Gases; h20 and co2
  95. Heat transfer?
    transfer of heat from a magma chamber. Some of surround rock.
  96. What are the three main mechanisms to form magma?
    decompression; addition of volitiles (gases); heat transfer
  97. What is Lake Baikal in Russia?
    where land forming a MOR, continental rifts example. it is the the largest fresh water lake in the world. land is being stretched. NOT A PLATE BOUNDARY
  98. What are the intrusive igeneous structure?
    pluton, batholith, laccolith, sill, dike
  99. What is a pluton?
    BIG BLOB; old magma that has made its way to the surface
  100. Batholith
    HUGE HUGE HUGE BLOB or bunch of blob (plutons), most of the sierras are made of of batholiths
  101. What is a laccolith?
    UFO shaped; flat on bottom; oval on top
  102. What is a sill?
    horizontal intrusion
  103. What are dikes?
    vertical intrusions
  104. What are extrusive igneous structures?
    volcanos, magma chamber, crater, caldera,
  105. What is a magma chamber?
    a space below ground filled with magma
  106. What is a fissure?
    conduit to the crust that is cracked.
  107. What is a vent?
    a circluar or a fissure
  108. What is a crater?
    it is the opt of a volcano; yellow stone
  109. What is a composite volcano?
    felsic, viscous, violent, caldera colapse, EX: crater lake oregon; pyroclastic event
  110. What is a shield volcano?
    gently sloping mafic basaltic, runny lava, high in iron and magnesium, HUGE, no violent. low viscosity, Hawaii is the largest shield volcano on earth. kilauea: 50 eruptions since 1823.
  111. conduit to the crust that is cracked.
    Flows with warm, pasty surfaces wrinkle into smooth, glassy, rope like ridges
  112. What is an a'a'?
    If the surface layer of the lava freezes underneath, it becomes a jumble of sharp, angular fragments, creating a rubbly flow. It is foot slashing
  113. What were the steps used in the scientific method for the dinsaurs extinction?
    Step 1. Observation: italy's 1970's, geos working on 65mya rocks. KT boundary 65 mya ago rocks. Iriduim Spike (not common on earth) Step 2. Hypothesis, asteriod struck earth, kicked up debris, blocked sunlight, stopped photosynthesis Step 3: Gather evidence, all at 65mya, clay layer weathered glass, "the smoking gun" tektites, shocked quartz, iridium spikes, new animals. Step 4: Reject hypothesuis: stupidity, change climate, dinosur disease, mammals outcompeted dinosaur, dinosaur flatulence (ALL NOT TRUE). Scientific consensous: what ever is most probable given the evidence in hand: AN ASTROID DID IT>
Card Set
Geo Lec MidTerm 1
Geo Lec MidTerm 1