Lab 7 -PlateTectonics_activity (1)

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Oct 30, 2023

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Lab 7 – Plate tectonics GEOL 1121 Name: Cheikh Tanko This lab covers the mechanisms of plate tectonics and the resulting landforms and events we see and feel on Earth’s surface. At the end of this lab you should be able to: 1) Explain the theory of plate tectonics in your own words 2) Summarize the reasons for different plate boundary interactions and describe the resulting surface landforms and events. 3) Evaluate where on Earth’s surface we have plate boundaries and describe the processes happening at these boundaries. 4) Use current landforms on Earth’s surface to classify former plate boundaries. You should start by watching three videos on iCollege: Wegener and Continental Drift, Sea Floor Spreading Proof, and Plate Tectonics. The work your way through these questions, referring back to the videos as needed. Part 1: Plate Tectonics 1) In the above diagram, arrows denote the direction of movement of the crust and mantle, with numbers and letters above each boundary between plates. Name each numbered plate boundary, and what types of plates are involved. (15 pts) Name of the numbered plate boundary what types of plates are involved 1 Convergent Island Arc 2 Divergent Mid Oceanic Ridge 3 Convergent Continental Arc 4 Divergent Continental Rift 5 Convergent Orogenic Mountain

Lab 7 – Plate tectonics GEOL 1121 Name: Cheikh Tanko 2) Name the lettered bathymetric (sea-floor) features in the figure above that are created by plate tectonics (2 pts) A: Island Arc B: Mid Oceanic Ridge 3) Describe in your own words the following plate boundaries. Where on Earth would you expect to find an example of each boundary? (6 pts) Convergent: This occurs when two plates come together and can be found in the Himalaya’s. Divergent: This occurs when two plates move away from each other. Can be found in the mid ocean ridge. Transform: This occurs when plates pass each other. And can be found on the bottom of the oceanic floor. 4) Name two ways oceanic crust differs from continental crust? (2 pts) Continental crust is much older, granitic, and less dense than oceanic crust, which is made up of basaltic rock. 5) Thinking back to your igneous rock labs, what two elements might account for these differences? (2 pts) The oceanic crust is mafic and contains basalt, whereas the continental crust is felsic. These factors could explain the differences.

Lab 7 – Plate tectonics GEOL 1121 Name: Cheikh Tanko 6) Look at the above image and answer the following questions (hint: Ma means Mega- annum, or millions of years) a. Where is the oldest oceanic crust in the Atlantic? (1 pt) The oldest oceanic crust, which is about 200 million years old, is found near the continental margins in the Abyssal Plains. b. Where is the youngest oceanic crust in the Atlantic? (1 pt) The youngest oceanic crust is found near the Mid ocean Ridge and is less than 10 million years old. c. Explain why this variation in the age of the oceanic crust exists across the Atlantic Ocean. (2 pts) The divergent boundary at MAR causes variations in the age of Oceanic Crust. The new ocean crust is formed at the MAR, and the Divergent Boundary of the MAR shifts it away from the MAR and toward continental margins. As a result, the newest crust is found at MAR, while it becomes older as we move towards the Continents.

Lab 7 – Plate tectonics GEOL 1121 Name: Cheikh Tanko d. The feature in the middle of the Atlantic Ocean is called the Mid-Atlantic Ridge. Given your responses to the above questions, is this a convergent, divergent, or transform boundary? (1 pt) The Mid Atlantic Ridge is a Divergent Boundary where two Oceanic plates are moving apart .

Lab 7 – Plate tectonics GEOL 1121 Name: Cheikh Tanko