Test on Chapters 7-11 Monday, April 28, 2014 No Calculator Required

Transcription

1 Test on Chapters 7-11 Monday, April 28, 2014 No Calculator Required Chapter Sections: Oceans: Bathymetry: 8.3 Earth s Interior: Plate Tectonics: Study/Review: Chapter sections listed here in your textbook Video lessons Learning Log packets: These should ideally contain all of your notes and answers to all of the review questions and assessments Keys to the review questions and assessments are posted online

2 Chapter 7: Oceans 7.1: Introduction to Oceans Salinity (definition and where salt comes from) Earth s Five Oceans Importance of Oceans Oceans and Earth s climate Surface Ocean Currents Gyres and Coriolis Effect Deep Ocean Currents

3 The salt in the oceans comes from: minerals in the ocean floor gases released by volcanoes, and rivers that carry dissolved minerals out to sea.

4 Can you name Earth s five oceans?

5 Importance of Oceans Oceans are an important source of water for the water cycle. Oceans spread energy and heat from the hot equator to the colder poles. Phytoplankton produce most of the oxygen in the atmosphere.

6 Earth s Energy The oceans are able to store heat energy. The water on Earth prevents the planet from getting too hot or too cold. Water has high specific heat (requires lots of energy to change its temperature)

7 Oceans and Earth s climate The climates on the coastline are milder than they are inland because ocean-warmed air masses move over the oceans toward the land.

8 Surface Currents and Gyres The Sun s unequal heating of Earth and the Coriolis effect cause permanent global wind patterns. Surface ocean currents to form large rotating systems called gyres.

9 Oceans and Earth s Climate Deep ocean currents move below the surface of the ocean. They are slower than surface ocean currents.

10 Chapter 7: Oceans 7.2: Waves Parts of a wave Crest Trough Wavelength Amplitude Average Level of Motion Wave movement Circular, no movement below wave base Wind causes waves Fetch Wind speed Amount of time wind blows Tsunamis versus wind waves

11

12 More About Waves A wave causes a circular motion in the water as it passes by. Water waves have predictable behaviors.

13 Wind Causes Waves Most ocean waves are caused by friction between the wind and the ocean surface. Fetch is the amount of open water over which wind blows.

14 What Happens When Waves Meet When waves formed in different places come together, the waves add to and subtract from each other.

15 Tsunamis Compared to Wind Waves A tsunami is a huge wave made by a large disturbance like an underwater earthquake, landslide, or volcanic eruption.

16 Chapter 7: Oceans 7.4: The Ocean Floor Continental Margin Continental shelf Continental slope Continental rise Deep Ocean Floor Mid-ocean ridge Seamount Guyot Volcanic island arc Deep-ocean trench

17 The Ocean Floor Many of the important features of the oceans are hidden in deep water. The continental margin is the region around continents that includes the: continental shelf, continental slope, and continental rise.

18

19 Features of the Ocean Floor Maps can show the location of the continental shelf (light blue areas). The true ocean floor is called the abyssal plain. (dark blue) It is flat and smooth because a thick layer of sediment covers its features.

20

21 Bathymetry Scientists measure these great depths using a technology called echo sounding or sonar. A device on a ship sends sound waves outward from the bottom of the ship.

22 Bathymetry Sound waves from the ship echo off the ocean floor. It takes time for the echo to return to the ship. The longer the echo time, the deeper the water!

23 Chapter 10: Inside Earth 10.1: Sensing Earth s Interior Seismic waves, seismologist P-waves versus S-waves S-wave shadow zone

24 Wave Motion Two type of seismic waves that are important are primary and secondary waves. P-waves travel faster than S-waves and move with a forward-and-backward motion. Slower S-waves travel with a side-to- side motion.

25 10.1 Wave Motion By studying what happens to the waves on their path through Earth, scientists are able to make detailed maps of Earth s interior 1. When S-waves are produced on one side of Earth due to an earthquake, there is a large area on the other side where the waves can t be detected. 2. Scientists know that secondary waves do not pass through liquids. 3. With this fact and these observations, they realized that the outer core of Earth must be liquid.

26

27 Chapter 10: Inside Earth 10.2: Earth s Interior Crust Mantle Lithosphere Asthenosphere Lower mantle Outer core Inner core

28

29 The Crust and the Mantle The lithosphere includes the crust and a thin part of the mantle. What lies above the lithosphere?

30 The Crust and Mantle The aesthenosphere lies just under the lithosphere and is the outermost part of the lower mantle. The aesthenosphere is a slushy zone of hot rock with a small amount of melted rock.

31 The Earth s Interior The core is the name for the center of Earth. The outer core is made mostly of iron, and is so hot the iron is melted. The inner core is also made mostly of iron, but it is solid. Why is the inner core solid?

32 The Outer Core and Earth s Magnetic Field Earth s magnetic field is created by the motion of liquid iron in Earth s outer core. Earth s magnetic field protects the planet from harmful radiation from the Sun.

33 Layers of Earth Compare and contrast the details of the different layers of the Earth.

34 Chapter 10: Inside Earth 10.3: Earth s Surface Density differences of Earth s layers Crust floats on the mantle Continental crust floats higher than oceanic crust because it is less dense Convection cells Seismic tomography

35 Earth s Materials Sorted by Density Scientists conclude that Earth formed from the gas and dust that surrounded our young sun. At first, Earth s surface was made of the same materials as its center. Later, the materials melted and became fluid. More dense materials settle toward the center. Less dense materials rose toward the surface.

36 Earth s Materials Today aluminum and silicon, which have low densities, are common in Earth s crust. Earth s inner and outer cores are composed mostly of very dense iron.

37 Earth s Materials The oceanic crust is made mostly of basalt. The continental crust is made mostly of andesite and granite.

38 Rocks Float on Rocks! Earth s crust is made of different types of rock that are less dense than the mantle. It s hard to imagine rocks floating on other rocks, but this is what happens inside Earth!

39 Convection Cells Heating the lower mantle causes the material to expand. The result is a plume of hot lower mantle material rising up from near the core toward the lithosphere.

40 Convection cells Seismic tomography uses seismic waves collected from all over the world and combined on a computer to create a 3-D image of Earth s interior. The red blobs in the image are convection currents of mantle rising toward Earth s surface from the core.

41 Chapter 11: Plate Tectonics 11.1: Pangaea Alfred Wegener Continental Drift Evidence for Pangaea Plate Tectonics

42 Pangaea Alfred Wegener was a German climatologist and arctic explorer who suggested the concept of continental drift. Continental drift is the idea that the continents move around on Earth s surface.

43 Movement of Continents Wegener thought that the continents we know today had once been part of an earlier supercontinent. He called this great landmass Pangaea.

44 Movement of Continents The surface of Earth is broken into many pieces like a giant jigsaw puzzle. Plate tectonics describes how these pieces move on Earth s surface.

45 Evidence for Continental Drift Wegener s belief was a scientific hypothesis based on observations. Continental drift was not accepted by all scientists because there was no evidence at the time to explain how continents could move.

46

47 11.1 Evidence for Continental Drift Coal beds stretch across the eastern U.S. and continue across southern Europe. Matching plant fossils are found in South America, Africa, India, Australia, and Antarctica. Matching reptile fossils are found in South America and Africa. Matching early mammal fossils are found in South America and Africa. Fossils in South America and Africa are found in rocks of identical age and type. Matching rock types and mountain belts occur in North America and the British Isles, and Africa and South America. Evidence of glaciers is present in regions with warm, dry climates. Continents that are close to the equator today were once closer to the South Pole in the distant past.

48

49 Chapter 11: Plate Tectonics 11.2: Sea-Floor Spreading Harry Hess and Marie Tharp (Bathymetry) Mid-ocean ridges Magnetic reversal patterns Sea-floor spreading How Wegener s hypothesis of continental drift was shaped into the modern theory of plate tectonics Oceanic versus continental plates Can a plate have more than one type of crust on top of it? How convection cells drive the movement of lithospheric plates Subduction Hot spots and island chains Hawaiian island formation

50 Sea Floor Spreading American scientists Harry Hess and Marie Tharp helped develop the theory of plate tectonics. Hess and Tharp helped map the ocean floor.

51 Undersea Mountains Discovered Bathymetric maps showed undersea mountain chains that formed a continuous chain down the centers of the ocean floors. Hess (and Tharp) wondered if new ocean floor was created at these mid-ocean ridges.

52 Sea Floor Spreading

53 Development of the Sea floor Spreading Hypothesis The key to sea-floor spreading was the discovery that there are matching magnetic patterns in the rocks on either side of the mid-ocean ridges. Matching magnetic patterns and the age of rocks on either side of mid-ocean ridges provided strong evidence for sea-floor spreading.

54

55 Types of Lithosphere There are two kinds of lithospheric plates: oceanic plates and continental plates.

56 What Drives Lithospheric Plates? Convection cells in Earth s lower mantle drive the lithospheric plates on the surface. Heated lower mantle material rises toward Earth s surface.

57 What Drives Lithospheric Plates? Cooling makes the nearby material denser and it sinks deeper into the lower mantle. This sinking process is called subduction.

58 Hot Spots and Island Chains A single hot rising plume, called a mantle plume, can cause a volcanic eruption in the plate above it. If the eruption is strong and lasts long enough, the volcanic eruption may form an island on the plate.

59 Hot Spots and Island Chains After the island forms, the movement of the plate carries it away from the mantle plume. Scientists determine the direction and speed of plate movement by measuring these island chains.

60 Chapter 11: Plate Tectonics 11.3: Plate Boundaries Divergent Mid-ocean ridges Rift valleys Pillow lava Convergent Mountains Trenches* Volcanic island arcs* Volcanic mountains* *Subduction Transform Offsetting Earthquakes

61

62 Divergent Boundaries Divergent boundaries are found in the ocean as mid-ocean ridges. A divergent boundary is the line between two plates where they are moving apart. This type of boundary is found over the rising plume of a mantle convection cell.

63

64 Divergent Boundaries Divergent boundaries can also be found on continents as rift valleys. When a rift valley forms on land, it may eventually split the landmass.

65 Convergent Boundaries When oceanic plates collide, one subducts under the other. This forms a valley in the ocean floor called a trench.

66

67 Ocean-Ocean Subduction

68 Convergent Boundaries What happens if an oceanic plate and a continental plate collide? Which plate would subduct? The oceanic plate must subduct under the continental plate. A continental plate is simply too buoyant to subduct under an oceanic plate.

69 Ocean-Continent Subduction

70 Mountains and Convergent Boundaries What happens if an oceanic plate with a continent on it subducts under a continental plate? The continents cannot be sucked into the trench because their granite rocks. The two continents collide!

71 Mountains and Convergent Boundaries Mountain ranges are formed when continents collide.

72

73 Continent-Continent Collision

74 Transform Fault Boundaries A good clue for locating transform faults is offsetting. When seen from above, the feature will appear to make a zig-zag.

75 Transform Faults