HMS Challenger Kilo Moana

Oceanography

World map showing land/water Thompson Research Vessel Polar views of Earth distribution

Sonar process—multibeam and Diagram of land/water by latitude process— sidescan single beam

1 Passive Continental Margin Atlantic oceanic ridge

Satellite Altimeter • Continental shelf • Continental slope • Continental rise

Oceanic Ridge--Atlantic Oceanic Ridge—Indian Oceanic Ridge—Pacific

Atlantic Ocean Pacific and Indian Ocean Floor Sea-floor landforms—California Floor

H:\ES106\PowerPoint\AN12_001.mov

2 Sea floor sediment Seismic data and interpretation Collection of • Derived from land: ‘terra’ sea-floor – Terrigenous sediment cores – Composed of sand, silt and clay • Derived from organisms: ‘biota’ – Biogenous – Composed of shells and skeletons of marine animals and plants • Direct precipitation from sea water: ‘hydro’ – Hydrogenous – Salts, calcium carbonate, metal oxides, metal sulfides (near sea-floor hot springs)

Plankton Marine Sediment distribution Offshore oil platform

Methane Hydrate sample Salt production Methane Hydrate burning

3 Manganese Nodules Submerged edge of continental crust Basin size vs. ridge

• Function of amount of water in the sea • And number and size of oceanic ridges

http://geography.berkeley.edu/ProgramCourses/CoursePagesFA2002/Geog40/Geog40.Week7.html

Active Convergent Lithospheric Plates Continental Active continental Margins • Oceanic plate is subducted Margin—location • Deep-ocean trench is formed • Volcanism above subducted plate

• Narrow continental shelf • Deep sea trench catches terrigenous sediment • ‘Accretionary Wedge’ of caught sediment • At convergent boundary of plates

http://serc.carleton.edu/research_education/cyberinfrastructure/navdat/questions.html http://serc.carleton.edu/research_education/cyberinfrastructure/navdat/questions.html

Deep-Ocean Trenches Pacific and Indian Ocean Floor Passive continental • Active continental margins • Other convergent plate locations Margin— • Most are in the Pacific Ocean location

4 Passive Deep sea sediment fans continental Margin—cross section

Discovery of Turbidity Currents Sea-floor landforms—California Atoll formation

Atoll Oceanic Plateaus Pacific and Indian Ocean Floor

• Figure 10-19—Oceanic Plateaus

5 Pacific Lithosphere Action Oceanic Ridge--Atlantic Floor

http://www.soc.soton.ac.uk/CHD/classroom@sea/carlsberg/science/oceanic_constr.html

Oceanic Ridge—Indian Oceanic Ridge—Pacific Oceanic plate divergence

http://www.soc.soton.ac.uk/CHD/classroom@sea/carlsberg/science/constructive_margins.html

Rift valleys on oceanic ridges

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