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2010-03-15 17:07:56
plate tectonics vocabulary

the full version of the plate tectonics vocabulary
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  1. East Africa Rift Zone
    an active continental rift zone in eastern Africa that appears to be a developing a divergent tectonic plate boundary. It is part of the larger Great Rift Valley. The rift is a narrow zone in which the African Plate is in the process of splitting into two new tectonic plates and is home to some active as well as dormant volcanoes.
  2. Glomar Challenger
    a ship that collected fossil samples from areas around the Mid-Atlantic Ridge, with the newest fossils closest to the ridge, giving evidence of seafloor spreading.
  3. J Tuzo Wilson
    suggested that Hawaii and other volcanic island chains may have formed due to the movement of a plate over a stationary hotspot in the mantle.
  4. Exotic Terranes
    a group of rocks that has attached itself to a tectonic plate and migrated away from its place of origin.
  5. Pangaea
    single Landmass thought to have been the origin of all continents
  6. Young Ocean Floor
    new rock on the ocean floor caused by seafloor spreading; the movement of ocean floor away form either side of a mid-ocean ridge
  7. convergent
    border formed by the collision of two lithospheric plates
  8. convection cells
    looping pattern of flowing magma
  9. Gondwanaland
    sourthern landmass that broke away from pangaea and later formed South America, Africa, India, Australia, and Antarctica
  10. Layers of the Earth
    the lithosphere: made up of the crust and a portion of the mantle, is divided into moving plates that ride on the denser asthenosphere: the layer made of plastic rock just under the lithosphere
  11. Divergent
    boundary formed by two lithospheric plates that are moving apart
  12. continent-continent collision
    neither plate is subducted, because they have the same density, so the colliding edges are crumpled and uplifted, producing large mountain ridges including the Himalayas
  13. Uniformitarianism
    the theory that all geologic phenomena may be explained as the result of existing forces having operated uniformly from the origin of the earth to the present time
  14. subduction zones
    region where one lithospheric plate moves under another
  15. himalayas
    formed by the Eurasian and Indo-Australian plates colliding.
  16. Island Arcs
    chain of volcanic islands formed along an ocean trench
  17. Continental drift
    hypothesis stating that the continents once formed a single landmass, broke up, and drifted into their present locations
  18. hess and dietz
    hess suggested the hypothesis, later named seafloor spreading by Dietz, in which the valley at the center of a ridge is actually a rift in the earth's crust where magma wells up, creating new rocks.
  19. Ring of fire
    an area in the basin of the Pacific Ocean where a large number of earthquakes and volcanic eruptions occur, and is a direct result of plate tectonics and the movement and collision of crustal plates
  20. transform fault
    boundary formed where 2 lithospheric plates slide past each other (San Andreas)
  21. Wegener
    a german scientist who proposed a hypothesis known as continental drift, which stated that the continents had moved
  22. midocean ridges
    system of undersea mountain ridges that wind around the earth
  23. hawaii
    a chain of islands created by the pacific plate moving over a stationary hotspot wehre the magma rises above the mantle and crust to erupt on the seafloor
  24. ocean-continent collisions
    a collision where the less dense oceanic crust is subducted under the denser continental crust
  25. matching fossils
    wegener found identical fossil remains of Mesosaurus, an extinct reptile, on both eastern South America and western Africa, and since they couldn't have swam all that way and there weren't any known land bridges, they must have been connected at some point.
  26. trenches
    deep valleys in the ocean floor
  27. hotspots
    areas of volcanism within a lithospheric plate
  28. Radioactive decay
    a useful way of telling geologic time... radiometric dating is a method of obtaining a rock's age by measuring the relative abundance of radioactive and radiogenic isotopes
  29. magnetic reversals
    mirrored patterns of reverse polarity and normal polarity on the ocean floor, with the line of symmetry being an ocean rift
  30. 225-200 million years ago
    the supercontinent, Pangaea, began to break up, eventually forming the continents we know today
  31. San Andreas Fault
    a major transform boundary between the Pacific Plate and the North American plate
  32. new madrid earthquake
    an intraplate earthquake that can be estimated to have an 8.0 or greater magnitude on the not yet invented Richter scale
  33. magnetic stripes
    stripes of reveresed polarity and normal polarity that can be found on the oceans floor symmetrically on the sides of a rift.
  34. earthquake zones
    an area of the earth's crust wehre movements, sometimes volcanism, occur. it is also known as a seismic area
  35. volcano
    lava and pyroclasitc material built up on the earth's surface around a vent
  36. 2.5 to 15 centimeters per year
    the pace at which the earth's tectonics plates move
  37. gps
    • global positioning system...
    • using these you can figure out where a certain thing is and then measure the distance it moves
  38. laurasia
    northern landmass that broke away from pangaea and later formed north america and eurasia
  39. sea-floor spreading
    evidence of plate movement...
  40. ocean-ocean collision
    a deep ocean trench forms when these plates are subducted