Presentation on theme: "Chapter 10, Section 2. Key Terms Create a flashcard for each of the following terms (found on p.247 in your text book). Plate tectonics Lithosphere."— Presentation transcript:
Chapter 10, Section 2
Key Terms Create a flashcard for each of the following terms (found on p.247 in your text book). Plate tectonics Lithosphere Asthenosphere If you finish early, study your flashcards!
Plate Tectonics The theory of Continental Drift led to the theory of PLATE TECTONICS. PLATE TECTONICS explains how large pieces of the lithosphere, called plates, move and change shape. Earth’s crust and the rigid, upper part of the mantle = LITHOSPHERE. This is the thin outer shell of Earth (like an Egg shell). The lithosphere is broken into several pieces called TECTONIC PLATES. The TECTONIC PLATES ride or float on the ATHENOSPHERE (part of the Earth’s mantle that is flowing slowly).
Earth’s Crust OCEANIC CRUST = dense, made of iron and magnesium-rich rock. CONTINENTAL CRUST = low density, made of rock rich in silica. Both kinds of crust are always moving with the tectonic plates they are riding on.
Tectonic Plates 15 major tectonic plates.
Earthquakes and Volcanoes Frequent earthquakes in an area are evidence the 2 or more tectonic plates meet in that area. Many volcanoes form from plate motion and help scientist identify plate boundaries.
Quick Check!! 1.The upper and hard part of the Earth’s mantle is called the ______________________. 2.The two types of crust are continental and ____________. 3.Scientists have identified about ______ major tectonic plates. 4.Name one plate: ______________________________________________________ ______________________________________________________ ______________________________________________________ _______________
Types of Plate Boundaries Most of the dramatic changes in Earth’s crust---Volcanoes and Earthquakes--- occur at Plate Boundaries. DivergentConvergent Transform
Divergent Boundaries 2 plates move away from each other. Magma from the athenosphere rises to the surface as the 2 plates move apart, the magma cools and creates new oceanic lithosphere(sea-floor spreading).
Convergent Boundary 2 plates collide 3 types of Collisions
Types of Collisions Oceanic Lithosphere vs. Continental Oceanic is denser so it sinks under the continental lithosphere Called a SUBDUCTION ZONE Deep-ocean trenches and Volcanoes form at SUBDUCTION ZONES Continental vs. Continental Lithosphere Neither plate subducts Colliding edges crumple and thicken causing uplift that forms large mountain ranges. Oceanic vs. Oceanic Lithosphere One plate subducts under the other Deep ocean trench forms Magma rises to form and ISLAND ARC, or chain of Volcanic Islands
Transform Boundaries 2 plates slide past each other horizontally The edges of the plates scrape and jolt along each other. This motion is felt as Earthquakes. No Magma is produced
Summary—Plate Boundaries DivergentPlates moving away from each other to form rifts and mid- ocean ridges North American and Eurasian plates at the Mid-Atlantic Ridge. Red Sea. ConvergentPlates moving toward each other and colliding to form ocean trenches, mountain ranges, volcanoes, and island arcs South American and Nazca plates at the Chilean trench along the west coast of South America. Himalyan mountains, Japan. TransformPlates sliding past each other while moving in opposite directions North American and Pacific Plates at the San Andreas fault in California.
Quick Check!! 1.Name the 3 types of plate boundaries: ____________________________________ ____________________________________ ____________________________________ 2.San Andreas fault is an example of a _________ boundary. 3.2 plates moving apart is a _________ boundary. 4.Mid-Atlantic Ridge is causing South America and _______ to spread apart.
Mantle Convection 1.Heat from the Earth’s core heats the material in the Mantle. 2.The heated material expands and becomes less dense therefore rising around the cooler, denser material above it. 3.This cycle continues, this is called CONVECTION. 4.Convection currents cause the tectonic plates above it to move.
Plate Tectonics Animation
Plate Tectonics Video Clip
Tectonic Plate Boundary Activity In your group you will create each of the 3 plate boundaries using modeling clay.
Assessment Make a 3-Flap Book showing each of the types of plate boundaries. For each flap include: --Definition/Description --Drawing --Real World Example