Plate Tectonics Types of Plate Movement Objective: I will be able to Describe the different types of plate boundaries. I know I understand when I can I can match a type of plate boundary to different pictures Do Now 11/12 Homework 1) Finish CW 16 1) Do Now # 7: Where do Google Form most earthquakes and volcanoes occur? Fill in due Mon on your Do Now sheet 2) CW 15 quiz on 11/18 3) Model Test 11/20 Watch the video below, explaining how the continents move Check your answers on CW 15 using the link below https://docs.google.com/document/d/1MbhXd mer4oVL3mm5lhDP8zelBWbBnD3iJOBwfDShZN E/edit?usp=sharing Your answers do not have to be the same as mine word for word but should cover the same main ideas Directions Read through the following slides before completing the Google Form for CW 16 Tectonic Plates • The lithosphere of the earth is broken up into small pieces. • These small pieces are called tectonic plates. • The tectonic plates move as the convection currents in the mantle turn and add new seafloor at divergent boundaries, and recycle old seafloor at convergent boundaries. Tectonic Plates Tectonic Plates • The location where two plates meet is called a plate boundary • Plates can move in three directions at plate boundaries: toward each other, away, or slide past Plate Boundary • As the plates move relative to each other, a few things can happen • We are going to explore what happens at each of the boundaries Transform Boundary plates slide past Transform boundary • Plates slip past each other, moving in opposite directions called a fault • are breaks in earth’s crust where rocks have slipped past each other • Earthquakes occur Transform Boundary- plates slip past each other Transform - occur at a fault Transform - cause earthquakes to occur Divergent Boundary plates move away from each other Divergent Boundary • Plates move apart from each other • Creates sea floor ridges in the ocean • Most occur along the mid-ocean ridges (new crust is added during sea-floor spreading) • Rift Valley is where several pieces of Earth’s crust have diverged on land Divergent - plates move away from each other Divergent - new sea floor is added at mid ocean ridges (in the ocean) Two Oceanic plates that diverge form a mid ocean ridge Divergent- a rift valley forms when 2 pieces of continental crust diverge on land Two continental plates that diverge form a rift valley Convergent Boundary plates move toward Convergent Boundary • Plates come together • Creates sea floor trenches when oceanic crust and continetal crust come together • The plate that is more dense sinks under the less dense plate • Oceanic crust is more dense than continental crust so it sinks underneath the continental crust. This process is called subduction - where old oceanic crust is recycled • Mountains occur on land Convergent - Trench: old oceanic crust sinks beneath continental crust in a process called subduction Convergent - when 2 continental crusts collide, it creates a mountain Recap Self Assessment Click through the following slides and ask yourselves the question that is there. Once you have mentally answered the question, click next to reveal the correct answer. #1 Great African Rift Valley What kind of boundary caused the african rift valley? A) Transform B) Divergent C) Convergent Answer: Divergent When 2 continental plates diverge on land, it is called a rift valley #2 The Himalayas What kind of boundary caused the Himalayas? A) Transform B) Divergent C) Convergent Answer: Convergent When 2 continental plates converge on land, it forms mountains #3 San Andreas Fault What kind of boundary caused the San Andreas Fault? A) Transform B) Divergent C) Convergent Answer: Transform When 2 continental plates slide past each other, it forms a fault. Earthquakes typically occur at a fault. This is why there are so many earthquakes in California. #4 Mariana Trench What kind of boundary caused the Mariana Trench? A) Transform B) Divergent C) Convergent Answer: Convergent When an oceanic crust and continental crust converge, it is called a trench. What is happening at the trench A) oceanic crust sinks beneath the continental because it is more dense B) continental crust sinks beneath of the oceanic crust because it is more dense C) new sea floor is added D) old sea floor is recycled E) both A & D F) both B & C Answer: E When a continental crust and oceanic crust converge, it forms a trench. At the trench, the oceanic crust sinks beneath the continental crust because it is more dense This process causes old seafloor to be recycled back into the mantle What is the name of the process that occurs at the trench A) Sea Floor Spreading B) Subduction Answer B: Subduction When old sea floor is recycled back into the mantle as the oceanic crust sinks beneath the continental crust, the process is called subduction. #5 Mid Atlantic Ridge, Iceland What kind of boundary caused the Mid Ocean Ridge ? A) Transform B) Divergent C) Convergent Answer: A Divergent when 2 oceanic plates move away from each other in different directions at a divergent boundary, it is called a mid ocean ridge What is happening at the mid ocean ridge A) oceanic crust sinks beneath the continental because it is more dense B) continental crust sinks beneath of the oceanic crust because it is more dense C) new sea floor is added D) old sea floor is recycled E) both A & D F) both B & C Answer C At a mid ocean ridge, as 2 oceanic plates move away from each other, new sea floor bubbles up from the mantle. This is why the age of the seafloor is brand new along mid ocean ridges. As new seafloor is added old sea floor gets pushed toward the trench where it will get recycled in the mantle. What is the name of the process that occurs at the mid ocean ridge A) Sea Floor Spreading B) Subduction Answer: A Sea Floor Spreading The process of adding new sea floor as two oceanic plates move away from each other or diverge is called sea floor spreading Map of Tectonic Plates Use the arrows in the map to determine where you see a divergent, convergent, or transform boundary Example: What kind of boundary exists between the Antarctic Plate and Pacific Plate? Answer: Divergent most likely, we would find a mid ocean ridge here because the plates diverge in the ocean What 2 boundaries surround the SA Plate What direction is SA plate moving Homework Complete the Google Form under CW 16. Remember to use these slides to help you. This Google Form is due by the start of class on Friday. There are also 2 videos at the beginning of the Google Form to help you.