-Volcanic features of mid-ocean ridge -Pillow lava or pillow basalts -Hot lava chilled by cold seawater -Smooth, rounded lobes of rocks. -Hydrothermal Vents: Infiltration of seawater into the crust, near a magma chamber. -Heated subsurface seawater migrates through cracks in ocean crust. -Once out, the water cools quickly, and forms a ?chimney? as it does so and it deposits what it was carrying. -Warm-water vents (type of chimney) -White smokers?Calcium carbonate. -Black smokers-Iron Bay of Bengal: Thickest sediments-about 2 kilometers of sediments.-Runoff from rivers from Himalayas. -Bioluminescence -Hydrothermal vents: -Dissolved metals precipitate to form metal sulfide deposits. -Unusual biological communities -Able to survive without sunlight. -Bacteria oxidize hydrogen sulfide gas to provide food -Terrogenic sediment (land) -rock fragments from land, volcanic ash -broken down by erosion -altered by chemical weather -Biogenic sediment (organisms) -hard skeletal parts (minerals) -silica or Cacium Carbonate Si CaCO3 Phyto Diatoms Cocoliths Zoa Radiolarions Foraminifera -Hyrdrogenic (Hydrogenous)-water -Chemical deposits, evaporates, phosphorites -Mn (Manganese) nodules, (Mn, Fe, Cu, Co, Ni) grow slowly, nucleate on fish teeth (only hard things left on see floors), etc. Basically, a ball of heavy metals. -Cosmogenic (cosmogenous)-from space -Particles from space, tektites, meteorites (Iron-rich). Continent-land Ocean-basalt At equator, North equatorial current, and South equatorial current, which take away the surface water and allowing for upwelling to occur. Resources from Marine sediments: -Energy Resources -Petroleum -Mainly from continental shelves -Gas hydrates -Sand and gravel (including tin, gold, etc.). Sand-for concrete -Evaporative salts -Manganese nodules and crusts -Diatomaceous earth-silaceous earth -Diatoms=Diatomaceous earth: -Light weight -Inert chemical composition -resistant to high temps -Excellent filter. -Good for killing parasites (too small to harm stuff like cows, but large enough to damage parasites) Glass=inert, resistant to high temps, etc. Sampling the Sea Floor: -Dredges, grab samplers -Corers (box, piston) -Acoustic profiling -sediment imaging -Pistons END CHAPTER 5.
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