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39 Cards in this Set
- Front
- Back
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the northern part of Pangea is called ____ and the southern part is called ______ |
Laurasia, Gondwanaland |
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Wegener’s idea of Pangea is called the theory of _____ _____ |
continental drift |
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geologists discovered that both the ____and ____ of waves from an earthquake change abruptly at certain depths as they pass through Earth |
speed, direction |
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oceanic crust is made mostly of: |
dark, dense basalt |
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continents are made mostly of: |
light-colored, less-dense granite |
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the mantle is made of: |
peridotite |
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Define: Lithosphere |
the crust and the uppermost mantle |
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3 properties of the lithosphere: |
1. cool 2. low pressure 3. produces hard, strong rock |
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Define: Asthenosphere |
layer of weak mantle rock that the lithosphere floats on top of |
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largest mountain chain on Earth is the |
Mid-Oceanic Ridge system |
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Define: normal magnetic polarity |
a magnetic orientation parallel to Earth’s current magnetic field |
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reversed magnetic polarity |
magnetic orientations that are the opposite of the current magnetic field |
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Define: Reversal |
the north magnetic pole becomes the south magnetic pole and vice versa |
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Define: Sea Floor Spreading |
the sea floor is spreading continuously away from the Mid-Oceanic Ridge |
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the lithosphere is broken into ___ segments called _____ |
7, tectonic plates |
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the upper parts of tectonic plates are made up of: |
continents and ocean basins |
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Define: Plate Boundary |
a fracture that separates one plate from another |
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neighboring plates can move relative to one another in three ways |
1. divergent boundary 3. convergent boundary 3. transform boundary |
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Define: Transform Boundary |
two plates slide horizontally past each other |
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Define: Subduction Zone |
a long, narrow belt where a lithospheric plate is sinking into the mantle, found at convergent plate boundaries |
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continental rifting |
when a divergent plate boundary rips a continent in half |
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when a oceanic plate converges with a continental plate: |
the denser oceanic plate sinks into the mantle beneath the edge of the continent |
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when two oceanic plates converge: |
the denser one sinks into the mantle |
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when two continental plates converge: |
they do not sink, they collide and crumple against each other, forming a huge mountain chain |
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A plate is: |
segment of the lithosphere |
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A single plate can carry both: |
oceanic and continental crust |
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a plate is composed of: |
hard, mechanically strong rock |
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after subduction begins, a tectonic plate sinks all the way to the: |
core-mantle boundary |
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Define: Convection |
upward and downward flow of fluid material in response to heating and cooling |
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Define: Mantle Plume |
relatively small rising column of plastic mantle rock that is hotter than surrounding rock that rise from great depths in the mantle |
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as pressure decreases in a rising plume, magma forms at a ____ ____ in the mantle |
hot spot |
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tectonic plates swept microcontinents together to form a single landmass called a: |
supercontinent |
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Define: Isotacy |
concept that the lithosphere is in floating equilibrium on the asthenosphere |
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Define: Isostatic Adjustment |
the vertical movement in response to a changing burden |
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2 Ways Plate Movements Affect Earth Systems |
1. earthquakes 2. volcanoes 3. mountain building |
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Volcanic eruptions are common at |
divergent and convergent plate boundaries |
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earthquakes are common at |
all plate boundaries |
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many mountains form at ____ _____ |
subduction zones |
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mountain chains sometimes form when: |
2 continents collide at a convergent boundary |
