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Chapter 3 Marine Provinces Essentials of Oceanography 7 th Edition.

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Presentation on theme: "Chapter 3 Marine Provinces Essentials of Oceanography 7 th Edition."— Presentation transcript:

1 Chapter 3 Marine Provinces Essentials of Oceanography 7 th Edition

2 Bathymetry Bathymetry is the measurement of ocean depths and the charting of the shape or topography of the ocean floor The ocean floor is a highly varied terrain that contains many interesting features Early methods of determining ocean depths involved using a long weighted line (called a sounding line)

3 Bathymetric techniques Echosounders send sound through water to determine water depth and sea floor features Figure 3-1

4 Bathymetric techniques Side-scan sonar uses a “fish” towed behind a ship to give a more detailed picture of the sea floor Figure 3-2

5 Bathymetric techniques Low frequency sound is used to determine structure beneath the sea floor Figure 3-3

6 Bathymetric techniques Satellites measure sea surface elevation, which mimics sea floor bathymetry Figure 3D

7 The hypsographic curve The hypsographic curve shows the relationship between the height of the land and the depth of the oceans Figure 3-4

8 Major regions of the North Atlantic Ocean floor Continental margin Ocean basin floor Mid-ocean ridge Figure 3-5

9 Passive versus active continental margins Passive margin No plate boundary Shelf Slope Rise Figure 3-6

10 Passive versus active continental margins Active margin Plate boundary Convergent Shelf Slope (steep) Trench Transform Continental borderland Figure 3-6

11 Submarine canyons and deep- sea fans Turbidity currents carve submarine canyons into the slope and shelf Debris from turbidity currents creates graded bedding deposits and deep- sea fans Figure 3-8a

12 Diver in the La Jolla Submarine Canyon Figure 3-8b

13 Abyssal plains Deep flat areas formed by suspension settling Volcanic peaks poke through the sediment Abyssal hills (seaknolls) Seamounts Tablemounts (guyots) Figure 3-9

14 Ocean trenches Deepest parts of the ocean Formed by plate convergence Most trenches are in the Pacific Ocean Associated with volcanic arcs Island arc Continental arc Figure 3-10

15 The mid-ocean ridge Circles the globe like the seam of a baseball Mostly traverses the middle of ocean basins A topographically high mountain range Entirely volcanic in origin Associated with plate divergence In the Pacific Ocean, called the East Pacific Rise In the Atlantic Ocean, called the Mid-Atlantic Ridge Internet flybys of portions of the mid-ocean ridge

16 The Mid-Atlantic Ridge Traverses the center of the Atlantic Ocean Contains a central down- dropped rift valley Comes above sea level in Iceland Figure 3-12

17 Features of the mid-ocean ridge Rift valleys Form when plates split apart Down- dropped areas associated with faults and earthquakes Figure 3-13

18 Features of the mid-ocean ridge Pillow lava Forms when hot lava comes into contact with cold seawater and quickly cools Basalt composition Figure 3-14

19 Features of the mid-ocean ridge Hydrothermal vents Form when seawater is heated by magma Black smokers emit hot water through chimneys Associated with metal sulfide deposits and unusual lifeforms Figure 3-15

20 Transform faults and fracture zones Transform Faults Occur between segments of the mid-ocean ridge Transform plate boundaries Movement in opposite directions Figure 3-16

21 Transform faults and fracture zones Fracture Zones Occur beyond segments of the mid-ocean ridge Not plate boundaries Movement in the same direction Figure 3-16

22 End of Chapter 3 Essentials of Oceanography 7 th Edition


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