Bell Ringer What is a continental slope and a continental shelf.

1. Bell RingerWhat is a continental slope and a continental shelf.

2. Earth Science Chapter 20 20.1 The Water Planet

3. 20.1 The Water Planet • ¾ of the earth’s surface lies submerged beneath salt water called global ocean. • Earth alone is called the water planet. • 97 % of all the water on earth is contained by the global ocean. • Mass of the ocean is 1/4000 of the mass of the earth as a whole. • Volume is about 800 times greater than the volume of water in the global ocean.

4. Divisions of the Global Ocean • 3 major oceans-Atlantic, Pacific & Indian • Water at the polar regions are called oceans. • They are really part of one of the major 3 • Artic is really part of the Atlantic • Sea is a smaller area of an ocean. • Ex. Mediterranean, Caribbean, & Coral Sea

5. Water in the Artic is less salty than the other oceans. • Pacific is the largest and deepest • The 2nd is the Atlantic which contains the Mediterranean, Caribbean, Gulf of Mexico and Baltic Sea. • Indian is the 3rd largest and contains the Arabian and Red Sea.

6. Exploration of the Ocean • Oceanography is the study of the physical characteristics, chemical, composition & life forms. • American naval officer, Matthew Maury used records from navy ships to learn about ocean currents, winds, depths, & weather conditions.

7. Challenger • British Navy ship H.M.S. Challenger laid the foundation for modern science of oceanography. • Team crossed the big 3 oceans and collected the data of water temperatures, depth of oceans, and samples of ocean water, sediments, and 1000’s forms of marine life.

8. Joides Resolution • World’s largest and most sophisticated scientific drilling ship. • Provided scientists with valuable data about plate tectonics and the ocean floor. • Floor is made up of continental crust and oceanic crust that lies beneath the ocean waters.

9. Submersibles • Underwater research vessels, that enable oceanographers to study ocean depths. • These are referred to as submarine robots. • Jason Jr. • Perform tasks ranging from photographing the ocean to collecting mineral samples.

10. Bathysphere • Spherical diving vessel that was first used for deep-ocean exploration. • Carried by an area of the ocean sphere, which carried scientists, but stayed connected to the research ship & life support.

11. Bathyscaph • Research ship self-propelled, free moving submarine equipped for deep ocean. • Alvin is a craft that holds a pilot and two scientists. • Alvin has made over 2000 dives. • Found marine life in deep hydrothermal water (hot water).

12. Robot submersibles • Study at great depths for long periods of time. • Argo was a seeing-eye robot vessel, that located the luxury ship called the Titanic.

13. Sonar • Research ships and submersibles are equipped with sonar to aid in mapping the ocean floor. • Sonar is an acronym for sound navigation and ranging. • Consists of a transmitter an receiver. • Bounces off the solid ocean floor and reflected back up to the receiver. • Measures the amount of time it takes to bounce back

14. Bell RingerWhat is a continental slope and a continental shelf.

15. 20.2 Features of the Ocean Floor • Divide into 2 major areas: continental margins and deep ocean basin. • Continental margins are shallower portions of the ocean floor. Consists of continental crust and thick wedge sediment. • Deep ocean basin is made up of oceanic crust and thin sediment.

16. Continental Margins • Part of the continental shelf and continental slope. • Real boundary lies offshore. • Part of the continent that is covered by ocean water is called the continental shelf. • Water above is shallow.

17. Are affected by changes in sea level. • Continental shelf along the east coast of the US has an average of 70 km in width. • Shelf along the west coast has an average width of 170 km.

18. Continental Slope • At the seaward edge of the continental shelf is a steeper slope called the continental slope. • Boundary between the continental crust and the oceanic crust is found at the base of the continental slope. • Continental shelf & continental slope may be cut by deep V-shaped valleys.

19. Submarine canyons • These are deep valleys. • Often associated with the mouths of major rivers. • Other canyons may have been caused by turbidity currents. • The turbidity currents are dense currents that carry large amounts of sediments down the continental slope.

20. Continental Rise. • Sediments that form a raised wedge at the base of the continental slope. • These sediments are deposited as the turbidity currents slow down.

21. Deep Ocean Basins • Distinctive features include: broad, flat plains, submerged volcanic mountains, gigantic volcanic mountain ranges, & deep trenches.

22. Trenches • Located in the deep ocean basin and are the deepest features on the earth’s surface. • Long, narrow places • Deepest in the world is the Mariana Trench in the Pacific Ocean near the island of Guam. • Most are located along the Pacific Ring of Fire.

23. Trenches continued • Trenches are associated with earthquakes, volcanic mountain ranges, and volcanic island arcs. • Deep trenches in the Pacific Ocean occur offshore from Japan. • Also, there are trenches found in the Alaska’s Aleutian Islands, the Philippines, & the west coast of South America.

24. Abyssal Plains • Extremely vast flat areas that lie in the deep ocean basins. • They are found in ocean depths greater than 4 km. • Cover about half of the deep-ocean basin. • Flattest regions on earth.

25. Facts about abyssal plains • Sonar reveals that the abyssal plains are made of sediments deposited in the deep ocean basin. • The abyssal plains of the Atlantic Ocean are close to the continental margins.

26. Mid-Ocean Ridges • Most prominent features of the ocean basin. • Continuous series of underwater mountain ranges that run along the ocean floors. • Only in Iceland, do mid-ocean ridges rise above sea level.

27. Facts of mid-ocean ridges • Form when ridge plates pull away from each other. • Have narrow depressions called rift. • A new crust separates and breaks into a series of faults called fracture zones.

28. Seamounts • Submerged volcanic mountains at least 1000 m high. • Submerged volcanic mountains less than 1 km are called abyssal hills. • Seamounts and abyssal hills are generally associated with hotspots. • Those that rise above the surface of the ocean form islands such as Hawaii & the Canary Islands.

29. Guyouts • These flat-topped, submerged seamounts.

30. 20.3 Ocean-Floor Sediments • Differ from one part of the ocean to another. • Continental slope and shelves are covered with sediments. • Samples in the deep-ocean basins are obtained by taking core samples. (Scoops of sediments)

31. Sources of Deep Ocean-Basin Sediments • Materials may come from organic or inorganic sources.

32. Inorganic Sediments • Most of these sediments are deposited along the shore & on the continental shelf. • Great quantities come from slides. • Some come from volcanic dust. • Icebergs provide some sediments. • Even meteorites contribute

33. Organic Sediments • Remains of marine plants and animals. • 2 most common substances are silica and calcium carbonate. • Silica comes primarily from microscopic organisms (diatoms & radiolaria).

34. Calcium carbonate comes from skeletons of tiny organisms called foraminifera. • Animals like coral and clams also add calcium carbonate to ocean-basin sediments.

35. Chemical Deposits • Make up part of the ocean floor sediments. • Potato-shaped lumps of minerals, or nodules, form on the abyssal plains. • Composed mainly of oxides of manganese, nickel, & iron.

36. others • Phosphorite are also formed directly in the ocean water.

37. Physical Classification of Sediments • Two types: Muds and ooze • 1st type is 40 % of ocean floor is covered with a soft, organic sediment called Muds. • 2nd type is ooze. • 30 % of the ooze is made up of organic materials.

38. Two types of ooze • 1st type is Calcareous ooze and is mostly calcium carbonate. • Never found in deep ocean water. • 2nd type of ooze is siliceous ooze. • Siliceous ooze is mostly silicon dioxide. • Most found in cool, nutrient-rich ocean waters near Antarctica.

39. Test • Will come from power point notes, worksheets, section questions, and chapter review questions. • Test will be Thursday