QUARTER 1 - LESSON 2 PALTE BOUNDARIES.pptx

lesson on plate boundaries

1. Plate Boundaries MELC: Describe the different types of plate boundaries; Explain the different processes that occur along the plate boundaries. Specific objectives: The learners should be able to: describe the different types of plate boundaries differentiate the types of convergent and divergent boundaries; and identify the places/plates that lie on the different types of boundaries. EARTH SCIENCE Grade 10

2. Map of plate boundaries Figure 1

3. types of plate boundaries

4. Divergent plate boundary Divergent Boundary is formed when two tectonic plates move apart from each other creating tension. Molten rocks called magma rise from the Earth’s mantle to the surface. The Earth’s surface is cool enough to solidify the magma that rose, thus, creating new oceanic crust or seafloor.

5. Types of divergent plate boundary Oceanic-Oceanic Divergent Plate Boundary undergoes the process of formation of new crust. The geologic features or events that may occur are oceanic ridge and earthquake. Example is the Mid-Atlantic Ocean Ridge formed between the South American Plate and the African Plate.

6. Types of divergent plate boundary Continental-Continental Divergent Plate Boundary undergoes the process of formation of new crust. The geologic features or events that may occur are the linear sea, rift valley , and earthquake. An example is the Red Sea formed between the Arabian Plate and the African Plate.

7. Processes and Landforms Along Divergent Boundary Divergent plate boundaries mostly happen under the oceans. As plates pull away from each other, a vertical space that may extend deep down into the lowest layer of the crust is created. It is a rift valley. The force of separation creates a tension zone. A shallow earthquake may happen with this plate movement.

8. Processes and Landforms Along Divergent Boundary

9. Processes and Landforms Along Divergent Boundary Plate divergence is believed to be a slow continuous process. As the plates move away, the gap between them increases. While this happens, materials from the mantle may rise, filling up the space. These materials pile up near the tension zone forming mountain-like structures called oceanic ridges. But new materials from the mantle may push the old ones. The filled-up space between the plates becomes a new seafloor. This process is known as seafloor spreading.

10. Convergent Boundary is formed when two plates move toward each other. This boundary has three types: Oceanic plate -Continental plate boundary, Two Oceanic plates boundary, and Two Continental plates boundary. convergent plate boundary

11. Types of convergent plate boundary Oceanic-Continental Plate Boundary The denser oceanic plate dives beneath the less dense continental plate. If one of the colliding plates is topped with oceanic crust, it is forced down into the mantle where it begins to melt. Subduction is the process by which a plate dives under a less dense plate. Magma rises into and through the other plate, solidifying into new crust. Magma formed from melting plates solidifies into granite, a light-colored, low-density rock that makes up the continents. Volcanic mountain arc and trench are formed. (ex: Cascade Range, Sumatra, Japan)

12. Types of convergent plate boundary Continental-Continental Plate Boundary Two thick continental plates collide and buckle into high mountains. The impact of the two colliding plates buckles the edge of one or both plates up into a rugged mountain range (ex: Himalayas Mountain Range).

13. Types of convergent plate boundary Oceanic-Oceanic Plate Boundary One oceanic plate dives below another oceanic plate. Volcanic island chain forms above the zone and trench parallel to the boundary. (ex: The Marianas). A chain of volcanoes often forms parallel to the boundary, to the mountain range, and trench. Powerful earthquakes shake a wide area on both sides of the boundary. The movement of the ground may cause a disturbance in the ocean. The water may flip or kick upwards to a few meters high. This is what we call tsunami, a Japanese term for harbor wave. This event is very dangerous when it moves inland, destroying lives and properties.

14. Processes and Landforms Along with Convergence of Plates A continental crust curves upward on top of the oceanic crust due to its lesser density. The oceanic crust, due to its greater density, stays below.

15. Processes and Landforms Along with Convergence of Plates When an oceanic crust converges with a continental crust, a crack between the crusts underwater, called trench , is formed. Subduction is the process by which a plate dives under a less dense plate. It turns into a hot molten material which we call magma . Due to the heat in the mantle, the magma builds up a pressure that enables it to push the ground above it. The column of rising magma is called a mantle plume. Convergence of oceanic and continental crust

16. Processes and Landforms Along with Convergence of Plates When there is volcanic activity such as an eruption, the ground moves, and so an earthquake is felt. Because subduction continues, a group of volcanoes, called volcanic arc , is formed at the surface of the continental crust along the boundary where the two crusts converged. The movement of the ground may cause a disturbance in the ocean. The water may flip or kick upwards to a few meters high. The water may flip or kick upwards to a few meters high. This is what we call tsunamis , a Japanese term for harbor wave . Convergence of oceanic and continental crust

17. Processes and Landforms Along with Convergence of Plates In the convergence between two oceanic crusts, one dives or subducts under the other. The figure shows two crusts underwater, so they are both oceanic crusts. Oceanic Crusts Convergence

18. Processes and Landforms Along with Convergence of Plates The front part of the subducting plate becomes magma upon reaching the mantle. Then it builds up pressure due to heat, pushes the crust above it, forming a volcano. This is a continuous process. This explains why the Philippines is mostly loaded with volcanoes. The different islands were believed to have originated from the convergence of two oceanic crusts. Oceanic Crusts Convergence

19. Processes and Landforms Along with Convergence of Plates Converging continental crusts or plates result in a collision zone, which could cause shallow earthquakes. At that place, a crack called fault is formed. This type of convergence will cause no subduction since the two plates have the same densities. There would be no volcanoes formed, no tsunamis. The convergence will result in a group of high landforms that we call mountain ranges. Converging continental crusts

20. TRANSFORM plate boundary Transform fault boundary is formed when two plates are sliding past each other. It is also called the Strike-slip fault. Rocks that line the boundary split into pieces as the plates slip at each other. A crack is then formed creating an undersea canyon or linear fault valley. San Andreas Fault is an example of this. (Examples; Alpine Fault )

21. Processes and Landforms Along Transform Fault Boundary This is characterized by plates moving horizontally against each other, producing a crack called fault on the ground. The force, the plates exert can break the rocks and other materials under the ground. The shaking usually ends abruptly. Therefore, it brings about strong earthquakes. The fault could swallow humans, cars, and buildings. Murky odorous water from under the ground may spring up from the fault. Most faults do not totally close when the shaking ceases since the adjoining edges have already moved farther from each other.