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Ch. 14. SC.912.N.1.1 SC.912.E.6.5, SC.912.E.7.1, SC.912.E.7.3.

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Presentation on theme: "Ch. 14. SC.912.N.1.1 SC.912.E.6.5, SC.912.E.7.1, SC.912.E.7.3."— Presentation transcript:

1 Ch. 14

2 SC.912.N.1.1 SC.912.E.6.5, SC.912.E.7.1, SC.912.E.7.3

3 Objectives Recognize that most of Earth’s surface is covered by water. List Earth’s four main ocean basins and identify their locations. Describe the topography of the ocean floor compare it to land. Identify and describe three major technologies used to study the ocean floor.

4 Vocabulary – 8 minutes Oceanography Bathymetry Sonar Submersible

5 Essential Questions 1. How does the area of the Earth’s surface covered by the oceans compare with the area covered by land? 2. Name four ocean basins. Which of the four is the largest? Which is located almost entirely in the southern hemisphere? 3. How does the topography of the ocean floor compare to that on land? Name three topographic features found on the ocean floor. 4. What types of technology are used to study the ocean floor?

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7 Why The Blue Planet?

8 The Blue Planet Why the “blue planet” or the “water planet”? Nearly 71% of Earth’s surface is covered by the global ocean. Oceanography is a science that draws on the methods and knowledge of geology, chemistry, physics, and biology to study all aspects of the world ocean.

9 Geography of the Oceans The area of the Earth is about 510 million square kilometers. Of this total, approximately 360 million square kilometers (71%) is represented by oceans and smaller seas (Mediterranean & Caribbean Seas) The world ocean can be divided into four main ocean basins Pacific Ocean - largest Atlantic Ocean – ½ size of Pacific Indian Ocean – slightly smaller than Atlantic Arctic Ocean – 7% size of Pacific

10 Map

11 Arctic Ocean, Indian Ocean, Atlantic Ocean, & Pacific Ocean

12 Mapping the Ocean Floor If all water drained out of the ocean you would see different features such as: Chains of volcanoes Mountain ranges Large submarine plateaus The topography of the ocean floor is as diverse as that of continents.

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14 is the measurement of ocean depths and the charting of the shape or topography of the ocean floor. Bathos = depth Metry = measurement

15 Simple Sonar Is a type of electronic depth-sounding equipment. Sound Navigation and Ranging (acronym) Echo sounding Sonar works by transmitting sound waves toward the ocean bottom. Depth can be calculated from the speed of sound waves in water - 1500 meters/second- and the time required for the energy pulse to reach the ocean floor and return.

16 Multibeam Sonar Uses more than one sound source and listening device. Obtains a profile of a narrow strip of ocean floor rather than obtaining the depth of a single point every few seconds. Recorded every few seconds as the vessel advances.

17 Sonar Multibeam Sonar

18 Making A Map The vessel (ship) travels back-and-forth in a pattern across an area. Called “Mowing the lawn”.

19 Satellites Scientist have discovered the ocean floor is not flat. The mountains and ridges produce elevated areas on the ocean surface. Canyons and trenches cause slight depressions. Satellites are able to measure small differences by bouncing microwaves off the ocean surface.

20 Satellites Shows how the outgoing radar pulses are reflected back to a satellite. The height of the ocean surface can be calculated by knowing the satellites exact location.

21 Satellites bounce microwaves off the ocean surface. Outgoing radar pulses are reflected back to the satellite and can be used to detect differences in sea surface height that can be correlated to seafloor features.

22 Compare & Contrast (Fill in NOW!) Simple SonarMultibeam Sonar Satellite Method Type of data Advantages Disadvantages

23 Submersibles A submersible is a small underwater craft used for deep-sea research. Submersibles are used to collect data about areas of the ocean that were previously unreachable by humans. Submersibles are equipped with a number of instruments ranging from thermometers to cameras to pressure gauges. Operators can record video and photos of previously unknown creatures that live in the abyss.

24 Compare & Contrast Simple SonarMultibeam Sonar Satellite MethodSound waves Microwaves Type of dataOcean floor depth Ocean surface height, correlated to ocean depth AdvantagesSimple to useMore detailedMost detailed of all DisadvantagesTime consuming Must be cross- checked with sonar measurements

25 You will have 15 minutes to answer the essential questions in complete sentences. Each question is worth 5 points, to receive full credit you must have a complete answer. Be prepared to discuss answers with the class.

26 Nearly 71% of Earth’s surface is covered by oceans and 29% is covered by land.

27 The four ocean basins are the Pacific Ocean, Atlantic Ocean, Indian Ocean, and Arctic Ocean. The Pacific is the largest. The Indian ocean is almost entirely located in the southern hemisphere.

28 The topography of the ocean floor is as diverse as that of continents. Three topographic features mid-ocean ridges, trenches, and abyssal plains.

29 The technology used to study the ocean floor are sonar, satellites, and submersibles.

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31 Objectives List the three main regions of the ocean floor. Differentiate between the continental margins of the Atlantic and Pacific Oceans. Explain the formation of new ocean floor at deep- ocean trenches, abyssal plains, and mid-ocean ridges.

32 Vocabulary – Choose 5 words – 10 minutes Continental margins Continental shelf Continental slope Submarine canyon Turbidity currents Continental rise Ocean basin floor Abyssal plains Seamounts Mid-ocean ridges Seafloor spreading

33 Essential Questions 1. What are the three main regions of the ocean floor? 2. How do continental margins in the Atlantic Ocean differ from those in the Pacific Ocean? 3. What are trenches? How are deep-ocean trenches formed? 4. What are abyssal plains? How are abyssal plains formed? 5. What is formed at mid-ocean ridges?

34 Outlining- Reading Strategy

35 Oceanographers Divided the ocean floor into three major regions. The ocean floor regions are: The continental margins The ocean basin The mid-ocean ridge

36 Topography of the North Atlantic Ocean Basin

37 The zone of transition between a continent and the adjacent ocean floor basin floor.

38 Continental Margins In the Atlantic Ocean, thick layers of undisturbed sediment cover the continental margin. This region has very little volcanic or earthquake activity. This is because they are not associated with plate boundaries. In the Pacific Ocean, oceanic crust is plunging beneath continental crust. This force results in a narrow continental margin that experiences both volcanic activity and earthquakes.

39 Atlantic Continental Margin

40 In the Pacific Ocean, the oceanic crust is being pushed beneath the continental crust.

41 Continental Shelf The continental shelf is gently sloping submerged surface extending from the shoreline. The shelf is almost nonexistent along some coastlines. Continental shelves contain important mineral deposits, large reservoirs of oil and natural gas, and huge sand and gravel deposits. The waters of the continental shelf also contain important fishing grounds, which are significant sources of food.

42 Continental Slope Marking the seaward edge of the continental shelf is the continental slope. This slope is steeper than the shelf. And it marks the boundary between continental crust and oceanic crust. Deep steep-sided valleys known as submarine canyons are cut into the continental slope. May extend to the ocean basin floor.

43 Turbidity Currents Most information suggests that submarine canyons have been eroded, at least in part, by turbidity currents. Turbidity currents are occasional movements of dense, sediment rich water down the continental slope. Known to be an important mechanism of sediment transport in the ocean. They erode submarine canyons and deposit sediments on the ocean floor.

44 Submarine Canyons Most evidence suggests submarine canyons probably formed as river valleys during periods of low sea level during recent ice ages. Turbidity currents continue to change the canyons.

45 Continental Rise In regions where trenches do not exist, the steep continental slope merges into a more gradual incline known as the continental rise. The width of the continental slope averages about 20 kilometers, the continental rise may be hundreds of kilometers wide.

46 Continental slope marks the steep boundary between continental crust and oceanic crust. The continental rise occurs at the end of the continental slope and has a more gradual decline.

47 Lies between the continental margin and mid-ocean ridge.

48 Ocean Basin Floor Is the size of almost 30% of Earth’s surface. Includes: deep-ocean trenches, very flat areas known as abyssal plains, tall volcanic peeks called seamounts and guyots.

49 Deep Ocean Trenches Are long, narrow creases in the ocean floor that form the deepest parts of the ocean. Most trenches are located along the margins of the Pacific Ocean, and many exceed 10,000 meters in depth.

50 Deep-Ocean Trenches Trenches form at sites of plate-convergence where one moving plate descends beneath another and plunges back into the mantle. Earthquakes and volcanic activity are associated with these regions The large number of trenches and volcanic activity along the margins of the Pacific Ocean give the region its nickname as the Ring of Fire.

51 Abyssal Plains Are deep, extremely flat features. Most likely, the most level places on Earth. Have thick accumulations of fine sediment that have buried an otherwise rugged ocean floor.

52 Abyssal Plains The sediments that make up the abyssal plains are carried there by turbidity currents or deposited as a result of suspended sediments settling. Found in all oceans. The Atlantic Ocean has the most extensive abyssal plains because it has fewer trenches to catch sediment carried down the continental slope.

53 Submerged volcanic peaks that dot the ocean floor

54 Seamounts Are volcanoes that have not reached the ocean surface. Steep-sided cone shaped peaks are found on the floors of all oceans. Greatest number in the Pacific.

55 Seamounts - Guyots Once reach the surface they become islands. Erosion to sea level. Over millions of years, the islands gradually sink and disapear below the surface.

56 Once seamounts – the active, now-submerged, flat topped structures

57 Abyssal plains are deep, extremely flat regions of the ocean floor.

58 Found near the center of most ocean basins. New ocean floor is formed here.

59 Mid-Ocean Ridges An interconnected system of underwater mountains that have developed on newly formed ocean crust. The longest topographic feature on Earth’s surface (70,000 kilometers in length and 1,000-4,000 kilometers in width) Occupies up to ½ of the total ocean surface.

60 Broken into segments. Are offset by large transform faults where plates slide past each other horizontally, resulting in shallow earthquakes.

61 Seafloor Spreading A high amount of volcanic activity takes place on the crest of the mid-ocean ridge. Occurs at divergent plate boundaries where two lithospheric plates are moving apart. New ocean floor is formed at mid-ocean ridges as magma rises between the diverging plates and cools.

62 Hydrothermal Vents Form along mid-ocean ridges. Are zones where mineral rich-water, heated by the hot newly formed oceanic crust, escapes through cracks in oceanic crust into the water. As the super-heated, mineral-rich water comes in contact with surrounding cold water, minerals containing metals such as, iron (Fe), copper (Cu), and zinc (Zn) precipitate out and are deposited.

63 You will have 15 minutes to answer the essential questions in complete sentences. Each question is worth 5 points, to receive full credit you must have a complete answer. Be prepared to discuss answers with the class.

64 The three main regions of the ocean floor are continental margins, ocean basins, ocean basin floor, and mid-ocean ridge.

65 In the Atlantic Ocean, thick layers of undisturbed sediment cover the continental margin. This region has very little volcanic or earthquake activity. This is because they are not associated with plate boundaries. In the Pacific Ocean, oceanic crust is plunging beneath continental crust. This force results in a narrow continental margin that experiences both volcanic activity and earthquakes.

66 Trenches are long, narrow creases in the seafloor. They are formed at convergence sites where one plate descends beneath another and plunges back into the mantle.

67 Abyssal plains are deep, extremely flat features. Formed as sediments from coastal regions are transported far out to sea and settle on the ocean floor.

68 A new ocean floor is formed at mid-ocean ridges.

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70 You will be given 10 questions. Each question is worth 10 points. MUST be written in complete sentences.

71 Ch. 14 Check-Up Quiz 1. What percentage of Earth’s surface is covered by oceans? 2. Which ocean basin is the largest? 3. The use of sound waves to determine the depth of the ocean is called? 4. The gently sloping submerged surface that extends from the shoreline toward the ocean basin floor is the continental ____________. 5. Submarine canyons are believed to have been created by ________.

72 Ch. 14 Check-Up Quiz Cont. 6. What is bathymetry? 7. Why is multibeam sonar more efficient than simple sonar at collecting data from the ocean floor? 8. Compare and contrast deep ocean trenches to mid- ocean ridges. 9. In which ocean basin are most trenches found? Why? 10. What is the continental shelf? What economic significance do continental shelves have?

73 Objectives List the three types of ocean floor sediments. Describe the formation of terrigenous, biogenous, and hydrogenous sediments.

74 Vocabulary – 10 minutes Terrigenous sediment Biogenous sediment Calcareous ooze Siliceous ooze Hydrogenous sediment

75 Essential Questions 1. What are three types of ocean floor sediments? 2. What does terrigenous sediment consist of? 3. What is the composition of biogenous sediment? 4. How is hydrogenous sediment formed?

76 Types of Seafloor Sediment Originated… Comes from… Terrigenous Sediments Originated… Comes from… Biogenous Sediments Originated… Comes from… Hydrogenous Sediment

77 Distribution Of Ocean Floor Sediment Coarse-grained terrigenous deposits dominate continental margin areas. Fine-grained clay, or mud, is more common in the deepest areas of the ocean basins.

78 Distribution Of Ocean Floor Sediment

79 Types of Ocean Floor Sediment Classified by origin Categorized by: 1. Color 2. Particle size 3. Hardness

80 They are less dense and transported further than coarser sediments that settle closer to shore.

81 Ocean floor sediments can be classified according to their origin into three broad categories: terrigenous sediments, biogenous sediments, and hydrogenous sediments.

82 Terrigenous Sediment Originates on land. Consists primarily of mineral grains that were eroded from continental rocks and transported to the ocean. Larger particles such as gravel and sand usually settle rapidly near shore. WHY? Finer particles can take years to settle and may be carried thousands of miles.

83 Biogenous Sediments Biological in origin Consists of shells and skeletons of marine animals and algae. Debris produced by microscopic organisms that live in surface waters. Organisms die and their shells accumulate on the seafloor.

84 Biogenous Sediment (2 types) Most common – Clacerous ooze is produced from the calcium carbonate shells of organisms. Consistency of thick mud.

85 Biogenous Sediment (2 types) Siliceous ooze – composed mostly of shells of diatoms – single-celled algae – and radiolarians- single celled animals that have shells make out of silica. Phosphate rich biogenous sediments come from the bones, teeth, and scales of fish and other marine organisms.

86 Calcareous ooze and Siliceous ooze are two type of biogenous sediments.

87 Consists of minerals that crystallize directly from ocean water through various chemical reactions.

88 Hydrogenous Sediment – Most Common Types Manganese nodules are rounded, hard lumps of manganese, iron, and other metals. Calcium carbonates form by precipitation directly from ocean water in warm climates. Evaporites form where evaporation rates are high and there is restricted open-ocean circulation.

89 You will have 15 minutes to answer the essential questions in complete sentences. Each question is worth 5 points, to receive full credit you must have a complete answer. Be prepared to discuss answers with the class.

90 Three types of ocean floor sediments are terrigenous, biogenous, and hydrogenous.

91 Terrigenous sediments consist of mineral grains weathered from continental rocks.

92 Biogenous sediment is composed from shells and skeletons of marine animals and algae.

93 Hydrogenous sediment is formed when minerals crystallize directly from water through chemical reactions.

94 SC.912.N.1.1 SC.912.N.3.5 SC.912.E.7.3

95 Objectives Identify ocean resources used for energy production. Explain how gas hydrates are formed. List other types of ocean resources.

96 Vocabulary Gas hydrates Manganese nodule

97 Reading Strategy - details Sand & Gravel consist of are used for sometimes contains

98 Essential Questions 1. What are the main energy resources from the ocean? 2. How are gas hydrates formed? 3. What other resources are derived from the ocean? 4. What are the uses for evaporative salts?

99 Offshore Drilling Offshore drilling rigs tap the oil and natural gas reserves of the continental shelf. These platforms are near Santa Barbara, California.

100 Drilling platforms may provide structure for some marine organisms to live on; drilling may disturb some organisms or destroy habitats; an oil spill could be harmful to organisms in the immediate area.

101 Oil and natural gas are the main energy products currently being obtained fro the ocean floor.

102 Oil & Natural Gas The ancient remains of microscopic organisms are the source of today’s deposits of oil and natural gas. The percentage of world oil produced from offshore regions has increased from trace amounts in the 1930’s to more than 30% today. Part of this increase is due to advances in technology of offshore drilling platforms.

103 Location of Reserves Major offshore reserves exist in: The Persian Gulf The Gulf of Mexico Off the coast of southern California The North Sea The East Indies

104 Are compact chemical structures made of water and natural gas. Most common type of natural gas is methane.

105 Gas Hydrates Most oceanic gas hydrates are created when bacteria break down organic matter trapped in ocean-floor sediments. The bacteria produce methane gas along with small amounts of ethane and propane. All of which are flammable. These gases combine with water in deep-ocean sediments in such a way that gas is trapped inside a lattice-like cage of water molecules.

106 From the ocean floor include sand and gravel, evaporative salts, and manganese nodules.

107 Sand & Gravel Offshore sand and gravel industry is 2 nd in economic value only to the petroleum industry. Includes, rock fragments that are washed out to sea and shells of marine organisms, that are mined by offshore barges using suction devices. Used for landfill, to fill in recreational beaches, and to make concrete. May contain gem-quality diamonds, platinum, gold, and titanium.

108 Manganese Nodules Are hard lumps of manganese and other metals that precipitated around a smaller object. They contain high concentrations of manganese (Mn), iron (Fe), and smaller concentrations of copper (Cu), nickel (Ni), and cobalt (Co), all of which have a variety of economic uses.

109 Manganese Nodules Manganese nodules form when metals such as manganese (Mn) and iron (Fe) precipitate around an object, such as a grain of sand.

110 Evaporative Salts When seawater evaporates, the salts increase in concentration until they can no longer remain dissolved. When the concentration becomes high enough, the salts precipitate out of solution and form salt deposits.

111 Evaporative Salts Common table salt, or halite, is harvested from the salt left behind when ocean water evaporates. About 30% of the world’s salt is produced by evaporating seawater.

112 Halite Most economically important salt Highly used for seasoning, curing, and preserving foods. Also used in agriculture, clothing industry for drying fabric, and to de-ice roads.

113 28 minute video Write 10 interesting points from the video

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115 You will have 15 minutes to answer the essential questions in complete sentences. Each question is worth 5 points, to receive full credit you must have a complete answer. Be prepared to discuss answers with the class.

116 What are the main energy resources from the ocean? Oil and natural gas are the two main energy resources from the ocean.

117 How are gas hydrates formed? Most oceanic gas hydrates are created when bacteria break down organic matter trapped in ocean-floor sediments. The bacteria produce methane gas along with small amounts of ethane and propane. All of which are flammable. These gases combine with water in deep-ocean sediments in such a way that gas is trapped inside a lattice-like cage of water molecules.

118 What other resources are derived from the ocean? Other resources derived from the ocean floor include sand and gravel, evaporative salts, and manganese nodules.

119 What are the uses for evaporative salts? Evaporative salts are used for seasoning, curing, preserving foods, used in agriculture, to drying fabric, and to de-ice roads.


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