Ocean Mapping Lecture Notes PDF
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Uploaded by GoldenLeif427
North Carolina State University
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Summary
These lecture notes provide an overview of ocean mapping methods, from early techniques to modern satellite methods. They cover topics such as the characteristics of different ocean regions, continental margins, plate tectonics, and ocean features. The notes also discuss important concepts like the hypsographic curve and hydrothermal vents.
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Ocean Mapping Learning Outcomes: Explain methods used to map the seafloor including their strengths and weaknesses List and describe the three major ocean provinces and their subdivisions and major features Contrast active and passive continental margins including differences in tectonic a...
Ocean Mapping Learning Outcomes: Explain methods used to map the seafloor including their strengths and weaknesses List and describe the three major ocean provinces and their subdivisions and major features Contrast active and passive continental margins including differences in tectonic activity and sediment accumulation Identify and describe the formation of interplate features including seamounts and guyots Use the hypsographic curve to discuss the height of land, depth of the ocean and area of the Earth covered by land and sea 1 Early Ocean Mapping Fathom = 6 feet = 1.8 m Images: http://en.wikipedia.org/wiki/File:Mesure_du_fond_avec_la_sonde_sur_une_fr%C3%A9gate‐Morel_Fatio‐img_3163.jpg; http://oceanexplorer.noaa.gov/history/quotes/early/media/seafloor.html ‐ 1855 map by Maury 2 HMS Challenger – Made first systematic measurements in 1872 – Stocked 144 miles of rope for sounding – Made 492 bottom soundings – Deep ocean floor has relief 3 Echo Soundings Image: http://commons.wikimedia.org/wiki/File:Principle_of_SBES.jpg; Figure 3.2 in text 4 GLORIA Side Scanning Sonar Geological LOng-Range Inclined Acoustical Instrument Soundscape video https://oceanservice.noaa.gov/facts/sonar.html 5 Mapping from Space Uses satellite measurements Measures sea floor features based on gravitational bulges in sea surface Indirectly reveals bathymetry 6 Comparing Bathymetric Maps 7 Ocean Profiles 8 Ocean Provinces 9 Continental Margin Includes: Shelf Shelf break Slope Rise 10 Active and Passive Margins 11 Passive Margins – Not close to any plate boundary – No major tectonic activity – East coast of United States Image: http://geology.isu.edu/Digital_Geology_Idaho/Module3/mod3.htm 12 Active Margins 13 Deep Ocean Basin: Abyssal Plains Extend from base of continental rise Some of the deepest, flattest parts of Earth Suspension settling of very fine particles Well-developed in Atlantic and Indian oceans 14 Abyssal Hills and Seamounts Abyssal Hills Table Mount or Guyot 15 Mid‐Ocean Ridges 16 Mid‐Ocean Ridges: Hydrothermal Vents 17 White Smokers Release cooler water; 30 – 350oC Rich in barium, calcium and silicon Mineral precipitates are white = white "smoke” Create white chimneys 18 Black Smokers > 350oC Water temperatures exceed 350oC Solutions exiting vents are acidic (pH = ~3.5) and contain up to 300 ppm hydrogen sulfide (H2S) The black "smoke" is caused by dark sulfides Precipitates create black chimneys 19 Hypsographic Curve Figure 3.3A 20 Virtual Field Trip Blue Planet: The Deep Start at 22:40, stop at 47:50 to survey the ocean provinces (25 minutes – you’re welcome to watch more if you would like) As you watch take notice of the characteristics of each province – Light or dark? – Cold or warm? – Sediments or rocky? – High pressure? – Lots of life or a little? Is the life diverse? 21
