(Modified from) Chapter 3 Marine Provinces Essentials of Oceanography 7 th Edition

Learning Targets Be able to… Explain bathymetry Describe features of the sea floor Identify a passive vs. an active continental margin

Bathymetry Bathymetry is the measurement of ocean depths and the charting of the shape or topography of the ocean floor

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

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

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

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

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

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

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

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

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

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

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

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

Learning Targets Be able to… Explain bathymetry Describe features of the sea floor Identify a passive vs. an active continental margin

End of Chapter 3 Essentials of Oceanography 7 th Edition