1OceanographyHMS Challenger Kilo MoanaThompson Research VesselPolar views of EarthWorld map showing land/water distributionDiagram of land/water by latitudeSonar process—single beamSonar process—multibeam and sidescan2Satellite AltimeterPassive Continental Margin• Continental shelf• Continental slope• Continental riseAtlantic oceanic ridgeOceanic Ridge--Atlantic Oceanic Ridge—Indian Oceanic Ridge—PacificAtlantic Ocean FloorPacific and Indian Ocean FloorH:\ES106\PowerPoint\AN12_001.movSea-floor landforms—California3Seismic data and interpretationCollection of sea-floor sediment coresSea floor sediment• Derived from land: ‘terra’– Terrigenous– Composed of sand, silt and clay• Derived from organisms: ‘biota’–BiogenousBiogenous– 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 platformMethane Hydrate sampleMethane Hydrate burningSalt production4Manganese NodulesSubmerged edge of continental crust• Function of amount of water in the sea• And number and size of oceanic ridgesBasin size vs. ridgehttp://geography.berkeley.edu/ProgramCourses/CoursePagesFA2002/Geog40/Geog40.Week7.htmlActive Continental Margins• Narrow continental shelf• Deep sea trench catches terrigenous sediment• ‘Accretionary Wedge’ of caught sediment• At convergent boundary of plateshttp://serc.carleton.edu/research_education/cyberinfrastructure/navdat/questions.htmlConvergent Lithospheric Plates• Oceanic plate is subducted• Deep-ocean trench is formed• Volcanism above subducted platehttp://serc.carleton.edu/research_education/cyberinfrastructure/navdat/questions.htmlActive continental Margin—locationDeep-Ocean Trenches• Active continental margins• Other convergent plate locations• Most are in the Pacific OceanPacific and Indian Ocean Floor Passive continental Margin—location5Passive continental Margin—cross sectionDeep sea sediment fans Turbidity currentDiscovery of Turbidity Currents Sea-floor landforms—California Atoll formationAtoll Oceanic Plateaus• Figure 10-19—Oceanic PlateausPacific and Indian Ocean Floor6Atlantic Ocean FloorPacific Lithosphere Actionhttp://www.soc.soton.ac.uk/CHD/classroom@sea/carlsberg/science/oceanic_constr.htmlOceanic Ridge--AtlanticOceanic Ridge—Indian Oceanic Ridge—Pacific Oceanic plate divergencehttp://www.soc.soton.ac.uk/CHD/classroom@sea/carlsberg/science/constructive_margins.htmlRift valleys on oceanic
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