TYPES OF PLATE BOUNDARIES

EXPLAINS THE 3 TYPES OF PLATE BOUNDARIES
DIVERGENT
CONVERGENT
TRANSFORM

1. PLATE BOUNDARIE S By: Daryl F. Cadanilla

2. PLATE BOUNDARIES

3. 3 TYPESOF PLATE BOUNDARIES DIVERGENT PLATE BOUNDARY 2 lithospheric plates move away from each other CONVERGENT PLATE BOUNDARY 2 lithospheric plates move toward each other TRANSFORM FAULT 2 lithospheric plates slide past each other

4. DIVERGENT BOUNDARY Objectives: --Explain the processes that occur along divergent boundaries. --Determine the results of plates that are moving apart

5. Analyze the photographs of rift valleys and oceanic ridges and answer the questions that follow.

6. Questions: 1 . What are common in four pictures? 2.Million of years ago, landmasses in each picture were once connected .What do you think is happening to the Earth’s crust in those pictures? 3. If this event continues for million of years, what do you think will be the effect on the crust?

7. Short video https://www.youtube.com/watch?v=wfHwAeVNrzA

8. Types of divergent plate boundary 1. continental divergence -As the two plates pull apart, normal faults develop on both sides of the rift, and the central blocks slide downwards Early in the rift-forming process, streams and rivers will flow into the sinking rift valley to form a long linear lake. As the rift grows deeper it might drop below sea level, allowing ocean waters to flow in. This will produce a narrow, shallow sea within the rift . This rift can then grow deeper and wider. If rifting continues, a new ocean basin could be produced.

9. Example The   East Africa Rift Valley  is a classic example of this type of plate boundary. The East Africa Rift is in a very early stage of development. The plate has not been completely rifted, and the rift valley is still above sea level but occupied by lakes at several locations. The Red Sea is an example of a more completely developed rift. There the plates have fully separated, and the central rift valley has dropped below sea level.

10. GEOLOGICAL EFFECTS a rift valley sometimes occupied by long linear lakes or a shallow arm of the ocean; numerous normal faults bounding a central rift valley; shallow earthquake activity along the normal faults. Volcanic activity sometimes occurs within the rift.

11. 2. Oceanic Divergence When a divergent boundary occurs beneath oceanic lithosphere, the rising convection current below lifts the lithosphere, producing a mid-ocean ridge. Extensional forces stretch the lithosphere and produce a deep fissure. When the fissure opens, pressure is reduced on the super-heated mantle material below. It responds by melting, and the new magma flows into the fissure. The magma then solidifies and the process repeats itself.

12. example The Mid-Atlantic Ridge is a classic example of this type of plate boundary. The Ridge is a high area compared to the surrounding seafloor because of the lift from the convection current below.

13. GEOLOGICAL EFFECTS a submarine mountain range such as the Mid-Atlantic Ridge; volcanic activity in the form of fissure eruptions; shallow earthquake activity; creation of new seafloor and a widening ocean basin.

14. …..is divergent boundary also known as constructive plate boundary?   WHY

15. ASSESSMENT Which of the following is NOT an example of a divergent plate boundary? a. The boundary between the Nazca Plate and the South American Plate b. The boundary between the North American Plate and the Eurasian Plate c. The East African Rift d. The plate boundary that passes over Iceland

16. Which of the following describes a divergent boundary? When two plates collide with each other When two plates interact in any way c. When two plates move apart from each other d. When two plates slide alongside each other

17. What feature forms near divergent boundaries between two pieces of oceanic crust? a. Mid-ocean ridge b. Non-volcanic mountain c. Continental rift valley d. Trench

18. What feature forms near divergent boundaries between two pieces of continental crust? a.continental rift valley b. non-volcanic mountain c. mid-ocean ridge d. canyon

19. CONVERGENT BOUNDARY Objectives: --Explain the processes that occur along convergent boundaries. --Determine the results of plates that are moving toward each other

20. CONVERGENT PLATE BOUNDARY occur where the Earth’s tectonic plates collide or move toward one another. As the plates converge, the denser, thinner tectonic plate  subducts or dives beneath the lighter, thicker, more buoyant tectonic plate.

21. 3 TYPES 1. Continental convergence 2. Oceanic Convergence 3.Continental -Oceanic Convergence

22. 1. CONTINENTAL-CONTINENTAL https://www.youtube.com/watch?v=i7ZUAi0B7DA

23. Remember Continental plates are thicker but less dense than oceanic plates. Continental crust is too light to be carried downward into a trench. At continental-continental convergent margins neither plate subducts . The two plates converge, buckle,  fold , and fault. 

24. Example Himalayas when the Indian-Australian plate collided with the Eurasian plate. -Alps,( collision between African and Eurasian plate) Appalachians(Mountain range in the eastern United States and Canada) Atlas (series of mountain ranges in northwestern Africa)

25. GEOLOGICAL EFFECTS intense folding and faulting; a broad folded mountain range; shallow earthquake activity; shortening and thickening of the plates within the collision zone.

26. Mount Everest, the tallest mountain in the world, grows about 2.5 inches each year?   WHY

27. 2. OCEANIC - OCEANIC https://www.youtube.com/watch?v=L2XixysJgPs

28. Remember Older oceanic plates are denser than younger ones; denser plates subduct . An oceanic-oceanic collision is when two tectonic oceanic plates collide.  This convergence creates a subduction zone, which is where one plate is submerged below the other.

29. What happens after the subduction ? As the ocean floor  crust  (oceanic plate) loaded with sediments  subducts  into the softer  asthenosphere , the rocks in the subduction zone become  metamorphosed (alteration of the composition or structure of a rock)  under high pressure and temperature. After reaching a depth of about 100 km, the plates melt. Magma ( metamorphosed sediments and the melted part of the subducting plate ) has lower density and is at high pressure. It rises upwards due to the  buoyant force  offered by surrounding denser medium.

30. The magma flows out to the surface. A continuous upward movement of magma creates constant volcanic eruptions at the ocean floor. Constant volcanism above the subduction zone creates layers of rocks. As this process continues for millions of years, a volcanic landform is created which in some cases rises above the ocean waters. Such volcanic landforms all along the boundary form a  chain of volcanic islands  which are collectively called as  Island Arcs  

31. Example Formation of the Philippine Island Arc System Philippine Island Arc system is formed due to subduction of Philippine Sea plate under the  Sunda Plate (major continental shelf of the Eurasian plate). The trench formed here is called Philippine Trench Formation of the Indonesian Archipelago In the case of Indonesian Archipelago, the Indo-Australian plate is subducting below  Sunda Plate (part of Eurasian Plate). The trench formed here is called  Sunda trench (Java Trench is a major section of Sunda trench). Formation of the Caribbean Islands The Caribbean Plate is moving to the east while the North American Plate is moving to the west. The Mariana Trench or Marianas Trench , the deepest trench, is located in the western Pacific Ocean. The Mariana Trench is formed due to the subduction of the Pacific Plate below the Mariana Plate.

32. GEOLOGICAL EFFECTS a zone of progressively deeper earthquakes; an oceanic trench; a chain of volcanic islands; the destruction of oceanic lithosphere.

33. ….. oceanic convergence can cause tsunami?   WHY

34. 3. CONTINENTAL-OCEANIC https://www.youtube.com/watch?v=CL-tN_Ziobc

35. Remember Oceanic plates are thinner but denser than continental plates. When continental and oceanic plates collide, the thinner and more dense oceanic plate is overridden by the thicker and less dense continental plate. The oceanic plate is forced down into the mantle in a process known as " subduction ."

36. What happens after the subduction ? As the ocean floor  crust  (oceanic plate) loaded with sediments  subducts  into the softer  asthenosphere , the rocks in the subduction zone become  metamorphosed (alteration of the composition or structure of a rock)  under high pressure and temperature. After reaching a depth of about 100 km, the plates melt. Magma ( metamorphosed sediments and the melted part of the subducting plate ) has lower density and is at high pressure. It rises upwards due to the  buoyant force  offered by surrounding denser medium.

37. The magma flows out to the surface. Constant volcanism above the subduction zone creates layers of rocks. As this process continues for millions of years, a volcanic landform is created Such volcanic landforms all along the boundary form a  chain of volcano  which are collectively called as continental volcanic arcs 

38. EXAMPLES the Cascade volcanoes along the Washington-Oregon coast of North America (Juan de Fuca oceanic plate is subducting beneath the westward-moving North American continental plate) The Andes Mountain Range of western South America ( Nazca Plate is subducting beneath the South American plate.) Mount Mayon (between Eurasian plate and Philippineplate

39. GEOLOGICAL EFFECTS a zone of earthquake activity that is shallow along the continent margin but deepens beneath the continent; an oceanic trench; a chain of continental volcanic arc; the destruction of oceanic lithosphere.

40. ….. convergent boundary is also known as destructive boundary?   WHY

41. TRANSFORM FAULT BOUNDARY Objectives: --Explain the processes that occur along transform fault boundaries. --Determine the results of plates that are moving slide past each other

42. TRANSFORM FAULT BOUNDARY Transform boundaries are areas where the Earth's plates move past each other, rubbing along the edges. -- As the plates slide across from each other, they neither create land nor destroy it. Because of this, they are sometimes referred to as  conservative  boundaries or margins. 

43. EXAMPLES The  San Andreas fault  of California; Queen Charlotte Islands fault off western Canada   Magellanes-Fagnano fault system of South America.

44. GEOLOGICAL EFFECTS strike-slip faults can create deep, shallow earthquakes. The 2012 Sumatran quake was particularly powerful; its 8.6 magnitude was the largest ever recorded for a strike-slip fault.

45. Question: If "The Big One" happens on the San Andreas Fault, do we expect a large tsunami? Do we expect California to "fall into the ocean”? No! Earthquakes at transform boundaries, like the San Andreas fault, involve hardly any vertical motion. For an earthquake to generate a tsunami you need vertical disturbance.

46. Let’s check your understanding on different types of plate boundary. Identify the following geological effects to as what type of plate boundary they were formed/created. Answer all that apply. CHOICES -Oceanic divergence -Continental Divergence -Oceanic Convergence -Continental Convergence -Continental-Oceanic Convergence -Transform fault READY?

47. Rift Valleys Mountain ranges,no subduction Island Volcanic Arc Oceanic Ridges No geological formation No subduction Tsunami Continental Volcanic Arcs Trench Earthquakes

48. Label the diagram 5. What type of plate boundary is this? 6. Which lithospheric plate will subduct ?

49. HOT SPOT Objective: Relate hot spot with plate tectonics

50. Although many volcanoes form underwater in subduction zones or at divergent plate boundaries, some form on land. Areas where volcanoes that form on land away from tectonic plate boundaries are known as hotspots.

51. Watch and learn… https://www.youtube.com/watch?v=QO2OO1r_tFg

52. Let’s check your understanding. 1. In what layer of Earth does a hotspot volcano start? a. The core b. The surface c.  The mantle d. The crust

53. Let’s check your understanding. 2. How does magma get to the Earth's crust to create a hotspot volcano? a. Magma travels to Earth's surface through an upward tunnel from deep within Earth. b. Magma is created from asteroids hitting Earth's surface. c. Magma is created from meteors hitting Earth's surface. d. Magma comes from the sky and drops to the Earth.

54. Let’s check your understanding. 3. In a hot spot, Volcano A is on top of the mantle plume,Volcano B is 10 km farther from A while Volcano C is the farthest. What can you infer about the ages of the volcanoes? a. Volcano A is older than C b. VolcanoB is the oldest c. Volcano B is the youngest d. Volcano B is younger than C

55. By: DARYL F. CADANILLA Thank you and God bless!