1. The Sea Floor

4. Origin of the Ocean Water vapor released during degassing of early earth –volcanism Salt from chemical weathering

5. Methods of Studying the Sea Floor Rock Dredge Corer Sea-Floor Drilling Submersibles Echo Sounder Seismic Profiler Surveys - Magnetic, Gravity, Seismic Refraction Deep Sea Cameras

11. Features of the Sea Floor Continental Margins –Passive –Active Oceanic trench Mid-oceanic ridge Seamounts

13. Continental Shelves and Continental Slopes Vertical exaggeration in diagrams Continental shelf Continental slope Continental rise

16. Active Continental Margins On land- earthquakes, young mountain belt, volcanoes Continental shelf, continental slope, oceanic trench Oceanic Trenches –Earthquakes of the Benioff seismic Zones –Volcanoes –Low Heat Flow –Negative Gravity Anomalies

17. Submarine Canyons Abyssal Fans Bottom Currents Down-canyon movement of sand Bottom currents River erosion Turbidity Currents –Graded bedding –Shallow water fossils

19. Passive Continental Margins Continental shelf, slope, rise The Continental Rise –Types of Deposition From turbidity currents From contour currents Abyssal plains

22. Fracture Zones Offset rift valleys Transform Fault –Portion that has earthquakes

24. Seamounts, Guyots, and Aseismic Ridges Seamounts Guyots Aseismic ridges

29. Reefs Fringing Reefs Barrier Reefs Atolls

34. Sediments of the Sea Floor Terrigenous Sediment Pelagic Sediment –thickness increases away from crest of mid- oceanic ridge

35. Deep-sea sediments, those found at depths greater than about 500 m, cover roughly two-thirds of the Earth. The predominant deep sediment is carbonate ooze, which covers nearly half the ocean floor

36. The Mid-Oceanic Ridge Rift Valley Geologic Activity on the Ridge –Shallow-focus Earthquakes –High Heat Flow –Basalt Eruptions –Hot springs Black Smokers Biologic Activity on the Ridge –Geomicrobiology

43. Oceanic Crust and Ophiolites Evidence for composition of the oceanic crust Ophiolite (from top to bottom) –Marine sedimentary rock –Pillow basalt –Sheeted dike complex –Gabbroic intrusions –Ultramafic rock

46. The Age of the Sea Floor Younger than 200 million years old Parts of continents much older