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The Structure of the Earth and Plate Tectonics Lesson Objectives This lesson will teach you everything you need to know about the Structure of the Earth.

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Presentation on theme: "The Structure of the Earth and Plate Tectonics Lesson Objectives This lesson will teach you everything you need to know about the Structure of the Earth."— Presentation transcript:

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2 The Structure of the Earth and Plate Tectonics

3 Lesson Objectives This lesson will teach you everything you need to know about the Structure of the Earth and Plate Tectonics. By the end of this lesson you will be able to… 1.Name and describe Earth’s main layers. 2.Name and describe three types of plate boundaries

4 Instructions Complete this lesson on your own and at your own pace. Use the navigational buttons along the bottom to move throughout the lesson. Take notes as you go.The objectives (on the previous page) will be assessed by practice quizzes and on our Chapter Test. After linking to a website, simply close your browser window to return to this lesson. Have a pencil & paper handy. Have fun!

5 Structure of the Earth The Earth is made up of 4 main layers: –Inner Core –Outer Core –Mantle –Crust Inner core Outer core Mantle Crust

6 Structure of the Earth Working from the center of the Earth out we have: The inner core is a primarily solid sphere about 1220 km in radius situated at Earth's center. Based on the abundance of chemical elements in the solar system, their physical properties, and other chemical constraints regarding the remainder of Earth's volume, the inner core is believed to be composed primarily of a nickel-iron alloy, with small amounts of some unknown elements.

7 Structure of the Earth Working from the center of the Earth out we have: The liquid outer core is 2300 km thick and like the inner core composed of a nickel-iron alloy (but with less iron than the solid inner core). Iseismic and other geophysical evidence indicates that the outer core is so hot that the metals are in a liquid state.

8 Structure of the Earth Working from the center of the Earth out we have: The mantle is approximately 2,900 km thick and comprises 70% of Earth's volume. This is the largest layer!! In the mantle, temperatures range between degrees Celsius at the upper boundary with the crust to over 4,000 degrees Celsius at the boundary with the core.

9 The Crust This is where we live! The Earth’s crust is made of: Continental Crust & Oceanic Crust

10 The Crust Continental Crust Continental crust forms the land (the continents, as the name suggests) that we see today. Continental crust averages about 35 km thick. Under some mountain chains, crustal thickness is approximately twice that thickness (about 70 km thick). Continental crust is less dense and therefore more buoyant than oceanic crust Continental crust contains some of the oldest rocks on Earth.

11 The Crust Oceanic Crust As the name already suggests, this crust is below the oceans. Compared to continental crust, Oceanic crust is thin (6-11 km). It is more dense than continental crust and therefore when the two types of crust meet, oceanic crust will sink underneath continental crust. The rocks of the oceanic crust are very young compared with most of the rocks of the continental crust. They are not older than 200 million years.

12 Checkup Quiz: Move forward when you are ready to test yourself on the knowledge you gained! Review song/video of the layers

13 Checkup Quiz: Which layer is the rigid outer layer of the Earth? Crust Asthenosphere Mantle Outer core Inner core

14 Structure of the Earth The Earth is made up of 4 main layers: –Inner Core –Outer Core –Mantle –Crust Inner core Outer core Mantle Crust

15 Which layer is the rigid outer layer of the Earth? Crust

16 Checkup Quiz: Which layer of the earth is made of mostly solid metals? Lithosphere Asthenosphere Mantle Outer core Inner core

17 Structure of the Earth Video

18 Which layer of the earth is made of mostly solid metals? Inner core

19 Checkup Quiz: Which layer of the earth is made of mostly liquid metals? Lithosphere Asthenosphere Mantle Outer core Inner core

20 Structure of the Earth Video

21 Which layer of the earth is made of mostly solid metals? Outer core

22 Checkup Quiz: Which layer labeled as #5? Lithosphere Asthenosphere Mantle Outer core Inner core Hint: use the scale on the right of the figure!

23 Structure of the Earth The Earth is made up of 4 main layers: –Inner Core –Outer Core –Mantle –Crust Inner core Outer core Mantle Crust

24 Which layer labeled as #5? Outer core

25 What is Plate Tectonics?

26 If you look at a map of the world, you may notice that some of the continents could fit together like pieces of a puzzle.

27 Plate Tectonics The Earth’s crust is divided into 12 major plates which are moved in various directions. This plate motion causes them to collide, pull apart, or scrape against each other. Each type of interaction causes a characteristic set of Earth structures or “tectonic” features. The word, tectonic, refers to the deformation of the crust as a consequence of plate interaction.

28 World Plates

29 What are tectonic plates made of? Plates are made of rigid lithosphere. The lithosphere is made up of the crust and the upper part of the mantle.

30 What are tectonic plates made of? Take a look at both labels for lithosphere. The lithosphere is made up of either type of crust and the upper part of the mantle.

31 What lies beneath the tectonic plates? Below the lithosphere (which makes up the tectonic plates) is the asthenosphere.

32 Plate Movement “Plates” of lithosphere are moved around by the underlying hot mantle convection cells

33 Plate Movement Plate Movement only need the first :35 sec.

34 Plate Movement Continental drift is the movement of the Earth's continents relative to each other. The hypothesis that continents 'drift' was first put forward by Abraham Ortelius in 1596 and was fully developed by Alfred Wegener in 1912.

35 Exercise 1: Wegener On the back, explain your reasoning on the evidence. Try to logically piece the continents together so that they form a giant supercontinent. Use the handout in class to use to cut out and paste.

36 What happens at tectonic plate boundaries?

37 Divergent Convergent Transform Three types of plate boundary

38 Spreading ridges –As plates move apart new material is erupted to fill the gap Divergent Boundaries

39 In plate tectonics, a divergent boundary is a linear feature that exists between two tectonic plates that are moving away from each other. These areas can form in the middle of continents or on the ocean floor. As the plates pull apart, hot molten material can rise up this newly formed pathway to the surface - causing volcanic activity. Where a divergent boundary forms on a continent it is called a RIFT or CONTINENTAL RIFT, e.g. African Rift Valley. Where a divergent boundary forms under the ocean it is called an OCEAN RIDGE

40 Age of Oceanic Crust Courtesy of Ocean Ridges: This map shows the age of the oceanic crust. The red coloring shows the youngest ages, whilst the dark blue shows the oldest ages (around 200 million years old). Where are the Ocean Ridges located? Answer: Divergent boundaries

41 Iceland has a divergent plate boundary running through its middle Iceland: An example of continental rifting

42 There are three styles of convergent plate boundaries –Continent-continent collision –Continent-oceanic crust collision –Ocean-ocean collision Convergent Boundaries

43 Forms mountains, e.g. European Alps, Himalayas Continent-Continent Collision

44 Himalayas Continent-Continent Collision

45 Called SUBDUCTION Continent-Oceanic Crust Collision

46 At a convergent boundary where continental crust pushes against oceanic crust, the oceanic crust which is thinner and more dense than the continental crust, sinks below the continental crust. The oceanic crust descends into the mantle at a rate of centimeters per year Subduction is a way of recycling the oceanic crust. Eventually the subducting slab sinks down into the mantle to be recycled. It is for this reason that the oceanic crust is much younger than the continental crust which is not recycled.

47 Oceanic lithosphere subducts underneath the continental lithosphere Oceanic lithosphere heats and dehydrates as it subsides The melt rises forming volcanism E.g. The Andes Subduction

48 When two oceanic plates collide, one runs over the other which causes it to sink into the mantle forming a subduction zone. The subducting plate is bent downward to form a very deep depression in the ocean floor called a trench. The worlds deepest parts of the ocean are found along trenches. –E.g. The Mariana Trench is 11 km deep! Ocean-Ocean Plate Collision

49 The subducting plate is bent downward to form a very deep depression in the ocean floor called a trench.

50 Where plates slide past each other Transform Boundaries Above: View of the San Andreas transform fault

51 This map summarizes all the known plate boundaries on Earth, showing whether they are divergent, convergent or transform boundaries

52 Checkup Quiz : Move forward when you are ready to test yourself on the knowledge you gained! Plate Boundary Rap

53 Checkup Quiz: Movement of two plates often results a rift valley is which type of boundary. Convergent DivergentTransform

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55 Movement of two plates often results a rift valley is which type of boundary. Divergent

56 Checkup Quiz: Movement of two plates often results in mountains is which type of boundary. Convergent DivergentTransform

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58 Movement of two plates often results in mountains is which type of boundary. Convergent

59 Checkup Quiz: Movement of two plates toward each other is which type of boundary. Convergent DivergentTransform

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61 Movement of two plates toward each other is which type of boundary. Convergent

62 Checkup Quiz: Using what you know about the rock cycle, movement of two plates causing igneous rock is which type of boundary. Convergent DivergentTransform

63 Remember: Igneous rock is formed through the cooling and solidification of magma or lava. “NEW” rock

64 Using what you know about the rock cycle, movement of two plates causing igneous rock is which type of boundary. Divergent

65 Checkup Quiz: Using what you know about the rock cycle, movement of two plates causing metamorphic rock is which type of boundary. Convergent DivergentTransform

66 Metamorphic rocks arise from the transformation of existing rock types, in a process called metamorphism, which means "change in form". The original rock is subjected to heat and pressure, (temperatures greater than 150 to 200 °C and pressures of 1500 bars)

67 Movement of two plates often results a rift valley is which type of boundary. Convergent

68 Checkup Quiz: Scientists think continental plates move because of circulating liquid rock below the plates. TrueFalse

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70 Scientists DO think continental plates move because of circulating liquid rock below the plates.

71 Plate Tectonics Summary How are you doing? Are you able to describe all of the following? 1.Name Earth’s main layers.Earth’s main layers 2.Name and describe three types of plate boundaries.three types of plate boundaries. 1.If so, you are ready to move to the next slide! 2.If not click on the area you need help with!

72 Plate Tectonics: Well done! Only one thing left to do: Turn in your printed Wegener activity with your explanation of the evidence on the back.


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