Download Chapter 3: Marine Provinces

Measuring bathymetry

Ocean depths and topography of ocean
floor
Bathymetric techniques

Echo sounding/Sonar


Reflection of sound signals
Side-scan sonar
 Towed behind research vessel (ship)
 Ex.
GLORIA
Bathymetric techniques
Fig. 4.4 - Seismic Profiling
Bathymetric techniques, cont…
Fig. 3.2
Bathymetric techniques, cont…

Satellite
Measurements
 Ocean floor
features cause
sea surface to
rise
Marine provinces

3 major provinces

Continental margins


Deep-ocean basins


Shallow-water areas close to shore
Deep-water areas farther from land
Mid-ocean ridge

Submarine mountain range
Continental margins
Passive or active
 Passive (Atlantic-type)
 Not close to any plate boundary
 No major tectonic activity
east
 Ex:
coast of United
States

Continental margins, cont…

Active (Pacific-type)
Associated with convergent or
transform plate boundaries
 Much tectonic activity


Convergent active margin
Oceanic-continental convergence
western South America
 Ex:

Continental margins, cont…

Transform active margin
 Associated with transform plate
boundaries
 Ex: Coastal California along the
San Andreas
fault
Continental margins
Fig. 3.6
Continental shelf


Extends from shoreline to shelf break
Shallow, gently sloping
Continental slope

Submarine canyons cut into slope by
turbidity currents
 Mixture of seawater and sediments
 Move under influence of gravity
Continental rise

Transition between continental
crust and oceanic crust
Deep ocean basin features
 Depths
greater than 4000 m
 Abyssal plains
 Volcanic peaks
 Ocean trenches
 Oceanic ridges and rises
Abyssal plains

Very flat depositional surfaces
from base of continental rise
Volcanic peaks
Poke through sediment cover
 Below sea level:


Seamounts
Ocean trenches
Associated with subduction zones
 Deepest parts of ocean
 Ex. Mariana Trench

Mid-ocean ridge and rises



Longest mountain
chains
Basaltic lava
Divergent plate
boundary
Volcanic features of mid-ocean
ridge

Hydrothermal vents

Heated subsurface seawater migrates
through cracks in ocean crust