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Earth Science

Earth Science

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Earth Science

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  1. Earth Science Coach Williams Room 310B

  2. Chapter16 • Marine Environment

  3. Section16.1 Shoreline Features • Objectives: • Explain how shoreline features are formed and modified by marine processes. • Describe the major erosional and depositional shoreline features.

  4. Erosional Landforms • Headlands: land that sticks out into ocean • Wave refraction: shallow water causes waves to bend • Beaches: eroded headland materials • Erosion causes: • Cliffs, sea-stacks/arches, platforms, sea caves

  5. Erosional Landforms

  6. Beaches • Sloping band of sand, pebbles, gravel, mud at the edge of the sea • Erosion & sediments • Rocky coast = pebbles • Volcanic rock (Hawaii) = black sand • Corals/seashells = white sand

  7. Beaches

  8. Estuaries • Where freshwater river/stream enters ocean • Freshwater & saltwater mix

  9. Longshore Currents • Longshore bar: sand bar • Longshore current: current parallel to shore • Moves sediments • Rip currents: current out to sea through gap in sand bar

  10. Rip Current

  11. Depositional Features • Erosion/sediments causes change • Spits: narrow sand that sticks out in water • Barrier Island: long ridges of sand apart from the mainland • Lagoon: body of water behind barrier islands • Tombolo: strip of sand that connects mainland and island

  12. Spit

  13. Barrier Island

  14. Lagoon

  15. Tombolo

  16. Protective Structures • Artificial structures • Seawalls, groins, jetties, break-waters • Protect properties, beaches, etc… • Causes loss of sediments on beaches

  17. Protective Structures

  18. Changes in Sea Level • Global warming: rise • Melts ice • Water expands • Plate tectonics • Uplifts/sinking • Emergent coasts: uplift of coasts

  19. Section16.2 The Seafloor • Objectives: • Explain the reason for the existence of continents and ocean basins. • Compare the major geologic features of continental margins and ocean basins. • Describe the different types of marine sediments and their origin.

  20. Seafloor • Sonar/satellite imaging • Topography

  21. Oceanic/Continental Crust • Continental margin: submerged part of continent • Cont. Shelf • Cont. Slope • Cont. Rise

  22. Continental Margin

  23. Continental Shelves • Shallowest part of continental margin • Average depth: 130m • Was covered by water after ice age • Fishing • Oil, natural gas

  24. Continental Slopes • Sloping region beyond shelf • True edge of continent • Turbidity currents: currents along bottom of sea. • Fast moving; lots of sediment • Cut canyons along slope • Cont. rise: slope of deposits at base of slope

  25. Ocean Basins • Deeper parts of ocean floor • 60% of Earth’s surface • Abyssal plains: smooth parts of basin • Deep-Sea trenches: long depressions on basin • Mid-Ocean ridges: chains of underwater mountains on ocean basin (volcanoes) • Hydrothermal vents: hole in the seafloor where heated fluids erupt (magma)

  26. Abyssal Plain

  27. Deep-Sea Trenches

  28. Mid-Ocean Ridge

  29. Hydrothermal Vents

  30. Seafloor Volcanoes • Most of mountains on seafloor: extinct volcanoes • Seamounts: submerged volcanoes higher than 1km • Guyots: submerged volcanoes with flat tops

  31. Marine Sediments • Most are from land • Mud/sand by rivers • Dust/volcanic ash by wind • Ocean currents • Ooze: sediments from once-living organisms • Manganese nodules: sediment from valuable metals (looks like potatoes)