(Modified from) Chapter 3Marine Provinces

Essentials of Oceanography 7th Edition

Learning TargetsBe able to…

Explain bathymetry Describe features of the sea floorIdentify a passive vs. an active continental margin

BathymetryBathymetry is

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

Bathymetric techniquesSide-scan sonar uses a “fish” towed behind a ship to give a more detailed picture of the sea floor

Figure 3-2

Bathymetric techniquesSatellites measure sea surface elevation, which mimics sea floor bathymetry

Figure 3D

The hypsographic curveThe 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 marginOcean basin floorMid-ocean ridge

Figure 3-5

Passive versus active continental margins

Passive marginNo plate boundary

ShelfSlopeRise

Figure 3-6

Passive versus active continental margins

Active marginPlate boundary

ConvergentShelfSlope (steep)Trench

TransformContinental

borderland

Figure 3-6

Abyssal plainsDeep flat areas formed by suspension settlingVolcanic peaks poke through the sediment

Abyssal hills (seaknolls)SeamountsTablemounts (guyots)

Figure 3-9

Ocean trenchesDeepest parts of the oceanFormed by plate convergenceMost trenches are in the Pacific OceanAssociated with volcanic arcs

Island arcContinental arc

Figure 3-10

The mid-ocean ridgeCircles the globe like the seam of a baseballMostly traverses the middle of ocean basins A topographically high mountain rangeEntirely volcanic in originAssociated with plate divergenceIn the Pacific Ocean, called the East Pacific RiseIn the Atlantic Ocean, called the Mid-Atlantic RidgeInternet flybys of portions of the mid-ocean ridge

Features of the mid-ocean ridgeRift valleys

Form when plates split apartDown-dropped areas associated with faults and earthquakes

Figure 3-13

Features of the mid-ocean ridgePillow lava

Forms when hot lava comes into contact with cold seawater and quickly coolsBasalt composition

Figure 3-14

Features of the mid-ocean ridgeHydrothermal vents

Form when seawater is heated by magmaBlack smokers emit hot water through chimneysAssociated with metal sulfide deposits and unusual lifeforms

Figure 3-15

Learning TargetsBe able to…

Explain bathymetry Describe features of the sea floorIdentify a passive vs. an active continental margin

End of Chapter 3

Essentials of Oceanography 7th Edition