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CH 5 Plate Tectonics Section 51 Earths Interior

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Crust, Mantle, and Core, (Inner & Outer Core) Two types of evidence of the Earth's interior: Rock Samples (direct) - drilled ... Also reptile fossils helped. ... – PowerPoint PPT presentation

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Title: CH 5 Plate Tectonics Section 51 Earths Interior


1
CH 5 Plate Tectonics Section 5-1 Earths Interior
  • Earth is made up of 3 main layers
  • Crust, Mantle, and Core, (Inner Outer Core)
  • Two types of evidence of the Earths interior
  • Rock Samples (direct) - drilled holes as deep as
    12 km for samples.
  • Seismic Waves (indirect) shock waves produced
    by an earthquake. We look at the speed and path
    they take for info. (pg 126)
  • As you go towards the core the temperature and
    pressure will increase.

2
  • Crust think outer layer of the Earth, made of
    solid rock, that includes both dry land and ocean
    floor. (about 40 km thick)
  • Oceanic crust is made of Basalt.
  • Continental crust is made of Granite.
  • Mantle made up of very hot semi-solid rock,
    divided into layers based on physical properties.
    (about 3000 km thick)(80 total volume of the
    Earth)
  • Lithosphere very upper part of the mantle,
    basically the crust.
  • Asthenosphere below the lithosphere, where rock
    bends like a plastic (plasticity).
  • Lower Mantle bottom section extending to the
    core.

3
  • Core made mostly of metals nickel and iron
  • Outer core liquid part of the core.
  • Inner core dense ball on solid metal due to
    pressure.
  • Magnetic Field like a bar magnet through the
    middle of the Earth. Protects us from certain
    things in space (Radiation, Meteors).
  • Due to the molten outer core.
  • Page 131.
  • Causes compasses to work on the Earth.

4
Sec 5-2 Convection and the Mantle
  • Heat moves three ways on the Earth
  • Radiation transfer of heat energy through empty
    space (sunlight)
  • Conduction transfer of heat directly through
    touching (through a piece of metal)
  • Convection transfer of heat through a fluid
    like a liquid or a gas (water, air)
  • Movement occurs because of differences in density
    of the liquids as they heat up and cool down.
  • Hot goes up, and cold goes down.
  • - Heat from the core and the mantle itself
    causes convection currents in the mantle

5
Sec 5-3 Drifting Continents
  • Continental Drift states that all the continents
    were once joined together in a single landmass
    and have since drifted apart.
  • Alfred Wegener 1910 german scientist who
    discovered this. Called the supercontinent
    Pangea (all land)
  • Evidence that supports this continental drift
  • Land features like shape of coastlines, mineral
    deposits (coal), and glacial erosion.
  • Fossils like Glossopteris (fernlike plant) are
    found in rocks on Africa, South America, India,
    Australia, and Antarctica (page138-139). Also
    reptile fossils helped.
  • Climatic change also helped by showing some
    plants and animals could not live on the current
    land masses today because of temperature
    differences.

6
Sec 5-4 Ocean Floor Spreading
  • Mid-ocean ridges are where the plates pull apart
    under the oceans. They form under water mountain
    chains.
  • Sonar uses sound waves under water to map out
    objects echoes as they bounce back.
  • Sea-floor spreading occurs when both sides of the
    mid-ocean ridges pull apart and new crust is made
    between them.
  • They move like conveyor belts carrying the
    continents along with them.
  • Evidence for this include molten material,
    magnetic stripes on the ocean floor, and the age
    of the rocks.

7
  • Subduction Zones areas where ocean plates are
    pushed down into the mantle. Rock is recycled
    from Ch 4. Oceanic Crust (Basalt) is younger
    then Continental Crust (Granite)
  • - creates trenches along the edges of the
    oceans. (Mariana Trench 11033 meters)
  • Pacific ocean is shrinking due to subduction
    zones.
  • Atlantic ocean is growing due to ocean-floor
    spreading.

8
Sec 5-5 Theories
  • Theory of Plate Tectonics explains the formation,
    movement, and subduction of the Earths plates.
  • There are 3 different types of plate boundaries
    where movement occurs. (pg. 152-153)
  • Divergent Boundary two plates move apart from
    each other, or diverge.
  • Convergent Boundary two plates come together,
    or converge.
  • Transform Boundaries two plates slide past each
    other in opposite directions
  • History of the plates movement show a
    supercontinent called Pangea, (225 mya) which
    later split into two major landmasses called
    Laurasia (north) and Gondwannaland (south) (190
    mya)
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