3.-Plate-Movement.pdf

WEEK 6  Convection Current ~ Observe a pot of boiling water ~ Water is hotter near the bottom where the heat source is located. When cool water becomes denser, it sinks. Hot water on the bottom is pushed to the top This creates a convection current.  Convection A co...

WEEK 6  Convection Current ~ Observe a pot of boiling water ~ Water is hotter near the bottom where the heat source is located. When cool water becomes denser, it sinks. Hot water on the bottom is pushed to the top This creates a convection current.  Convection A convection cell is a circular pattern of density driven molten magma. Describing the Possible Causes of Plate 8 Movement Describing the Possible Causes of Plate 14 Movement  Slab Pull & Ridge Push This combination moves the ocean plates. Not separated from mantle convection, but are both caused by and help cause this convection. Continental plates are pushed around by oceanic plates. Describing the Possible Causes of Plate 15 Movement Describing the Possible Causes of Plate 16 Movement Plate boundary Crust The crust is the thinnest layer and the outermost layer of the earth Oceanic Crust 6 to 12 kilometers average thickness Mainly composed of basalt Density: 2.8 to 3.0 g/cm3 Continental Crust 30 to 70 kilometers average thickness Mainly composed of granite Density: 2.6 to 2.7 g/cm3 Plate Boundary It is the place where two plates meet. Plate Boundary Types of Plate boundaries: Convergent Divergent Transform Convergent Plate Boundary As plates move toward each other they produced a convergent boundary. In this type of boundary, plates colliding with one another. Convergent Plate Boundary ❑There are three scenarios that may happen in a convergent plate boundary: ❑ A continental plate and oceanic plate may collide ❑Two oceanic plate may collide ❑Two continental Plate may collide  Continental Plate & Oceanic Plate Collision When a continental plate and oceanic plate collide, the denser oceanic plate will subduct.  Collision of two Continental Plate ❑When two continental plate converge, a collision zone is formed. ❑Large group of tall mountains called mountain range are formed. Divergent Plate Boundaries Divergent Plate Boundary The place where two plates are moving away from each other. This is where the lithosphere is being pulled apart in opposite direction. East African Rift System One of the most extensive rifts on Earth’s surface, extending from Jordan in southwestern Asia southward through eastern Africa to Mozambique. The system is some 6,400 km long and averages 48–64 km wide. East African Rift System The three plates that are involved in the Afro- Arabian Rift System are the African (Nubian Plate), African (Somalian Plate) and Arabian Plate which are separating at different speeds. East African Rift System The Arabian Plate is moving away from Nubian Plate at a rate of about an inch (2.54 cm) per year. While the two African plates Nubian Plate and Somalian Plate are separating even slower, between half an inch to 0.2 inch (0.508 cm) per year East African Rift System The Afar Depression Triple Junction is landscape which includes the Danakil Desert and the lowest point in Africa, Lake Asal, less than 155 meters (510 ft) below Mid-Ocean Ridges occur along divergent plate boundaries, where new ocean floor is created as the Earth’s tectonic plates spread apart. As the plates separate, molten rock rises to the seafloor, producing enormous volcanic eruptions of basalt. Mid-Oceanic Ridge Mid-Atlantic Ridge runs down the center of the Atlantic Ocean, slowly spreading at a rate of 2 to 5 centimeters (0.8 to 2 inches) per year. Mid-Oceanic Ridge East Pacific is Rise spreading quickly, at rates of 6 to 16 centimeters (3 to 6 inches) per year.  Activity 3.Going Separate Ways Objectives: ❑ Explain the processes that occur along divergent boundaries. ❑ Determine the results of plates that are moving apart. Materials: photographs of Rift Valleys and Oceanic Ridge  Activity 3. Going Separate Ways Procedure: 1. Analyze the photographs of rift valleys (topmost pictures) and oceanic ridges below and answer the questions that follow. Going Separate Ways  Activity 3. Going Separate Ways Guide Questions: Q1. What are common in the four pictures? Q2. Millions of years ago, the land masses in each picture were once connected. What do you think is happening to the Earth’s crust in those pictures?  Activity 3. Going Separate Ways Guide Questions: Q4. Complete the drawing below to illustrate your answer in question number 4. Going Separate Ways  Going Separate Ways Guide Questions: Q3. If this event continues for millions of years, what do you think will be the effect on the crust?