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26 Cards in this Set
- Front
- Back
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How do we measure depth of the seafloor?
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Depth sounding- inaccurate
echo sounding- inaccurte because of changes in water = changes in speed Satelite altemetry photos. |
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whats the problem with satelite altimetry?
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it cannot see through the water.
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what is seismic profiling?
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Using an explosion and then waves are collected on different levels of the sea for evaluation (helpful in looking for oil).
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about what percent of earth is above sea level?
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30%
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about what percent of earth is above sea level?
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30%
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about what percent of earth is above sea level?
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30%
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about what percent of earth is above sea level?
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30%
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about what percent of earth is above sea level?
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30%
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what percent of the earth is actually above sea level
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30
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the continental margin consists of 4 segments. what are they?
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From shallow to deep.
Continental shelf Continental slope Continental rise Deep sea basin |
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What is important about the continental shelf?
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-Fisheries
-transportation -leisure -drilling and mining |
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What is important about the continental shelf?
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-Fisheries
-transportation -leisure -drilling and mining |
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What is important about the continental shelf?
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-fisheries
-mining and drilling -leisure -transportation |
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During the last ice age, what happened to the continental shelves?
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Water taht would cover the shelves was ice in glaciers and the sheld was not covered by water.
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There are two categories of continental margins. What are they and give an example of each.
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Active- seismically active as the pacific coast.
passive-seismically inactive as the atlantic coast. |
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How do we measure the continental slope?
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Rise / Run
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What are submarine canyons?
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Canyons found on the continental margins that form because of strong currents. They were drowned after the melting of the glaciers after the last ice age.
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How are the avelanches of water and sediment that cut the canyons formed?
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Underwater earthquakes.
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The same currents that cut the canyons displace the sediment that creates the continental rise. What are these currents called?
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turbidity currents
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what do we find in the deep sea?
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-Abyssal plains
-Abyssal hills -Seamounts -Guyots -trenches |
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The abyssal plains are considered
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the flattest structure in the world (no inclination/declination)
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what are seamounts
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Steep sided underwater volcanoes (built at hot spots or ridges)
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What are guyouts?
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flattened seamounts taht made it out of the ocean.
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What is the shape of a trench usually?
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Arc shaped
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Trenches are found where?
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at the base of an active margin
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What is the difference between an oceanic ridge and rise?
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Rise is fast spreading- flatter (Pacific)
Ridge is slowly spreading- taller (Atlantic) |
