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The Ocean Basins

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The Ocean Basins Physical Oceanography Features of the Ocean Basins Continental margin: portion of ocean made up of continental crust Features of the Ocean Basins ... – PowerPoint PPT presentation

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Title: The Ocean Basins


1
The Ocean Basins
Physical Oceanography
2
Features of the Ocean Basins
  • Continental margin portion of ocean made up of
    continental crust

3
Features of the Ocean Basins
  • continental shelf flat part of continental
    margin covered by shallow ocean water

Formed by changes in sea level Avg depth 60 m
4
Shelf
  • Relatively shallow
  • 0 200 m
  • Relatively flat with a gradient of 2 m drop per
    kilometre

5
Features of the Ocean Basins
  • continental slope boundary between continental
    crust and oceanic crust - The average angle
    displayed by the slope is about 5 degrees.

6
Features of the Ocean Basins
  • submarine canyons deep, v-shaped valley that
    cuts through shelf slope

7
Features of the Ocean Basins
  • continental rise wedge of sediments that
    separates slope from ocean floor

8
Features of the Ocean Basins
  • abyssal plain (floor) very flat areas at depths
    of 3-5 km

9
Features of the Ocean Basins
  • mid-ocean ridge mountain range on ocean floor
    due to seafloor spreading

10
Features of the Ocean Basins
  • trench deep narrow valleys along the edges of
    subduction zones in the ocean floor 90 of
    trenches are found around the Pacific rim.

Marianas Trench in Pacific ocean is the deepest
point on earth - 10,668 meters
11
Bathymetric Charts show the contours and depths
of the seafloor topography
12
General Slope Features
  • Sharp break from the shelf
  • Angle is gentle, averaging less than 5 degrees
  • Continues to a depth of 3600 m
  • Often carved by deep canyons - Hudson Canyon is
    famous in N.A.

13
Submarine Canyons
  • V-shaped
  • Hudson Canyon steeper than the Grand Canyon
  • Form deep sea fans from sediments
  • Originated from rivers during ice ages

14
The Gully!
  • Submarine canyon off Nova Scotia
  • Marine protected area because of the rare corals
    found there
  • The natural gas pipeline goes right by
    itproblems?

The Gully
15
Turbidity currents
  • Turbidity currents are caused by the slumping of
    sediments from the continental slope.
  • can travel at over 55 km/h
  • can spread 700 km
  • Can damage underwater pipelines, transatlantic
    cables

16
Rise
  • Slope about ½ degree toward the abyssal plain
  • Sediment deposition from continent
  • Range from 100 to 1000 km in width
  • Only occur along passive margins, often off the
    mouth of large rivers

17
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18
Another look ?
19
Features of the Ocean Basins
  • seamount underwater volcanic mountain (some
    more than 1000 m high)

20
Features of the Ocean Basins Atolls
  • A ring shaped island of coral reefs and coral
    debris. These often form over sinking inactive
    volcanoes.

21
Features of the Ocean Basins
  • coral reef limestone structures containing
    shells of animals that surround volcanic islands

22
Features of the Ocean Basins
  • guyot a flat-topped submerged seamount due to
    erosion

23
Features of the Ocean Basins
  • rift valley deep crevice in between mountain
    ranges

24
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25
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26
Which coast has the wider shelf?
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