Plate Tectonics Table of Contents Earths Interior Convection

Plate Tectonics Table of Contents Earth’s Interior Convection and the Mantle Drifting Continents Sea-Floor Spreading Theory of Plate Tectonics

Plate Tectonics - Earth’s Interior Exploring Inside the Earth Geologists have used two main types of evidence to learn about Earth’s interior: direct evidence from rock samples and indirect evidence from seismic waves.

Plate Tectonics - Earth’s Interior The Crust The crust is a layer of solid rock that includes both dry land the ocean floor.

Plate Tectonics - Earth’s Interior The Mantle Earth’s mantle is made up of rock that is very hot, but solid. Scientists divide the mantle into layers based on the physical characteristics of those layers.

Plate Tectonics Lithosphere and Asthenosphere The Lithosphere and Asthenosphere are two layers of the Mantle. Lithosphere (Litho means Stone in Greek) is the solid rocky upper layer of the mantle. It’s about 100 km (60 miles) thick on average. Asthenosphere (Asthenes means “Weak” in Greek) below the lithosphere this layer is softer and flows very slowly.

Plate Tectonics - Earth’s Interior The Core and magnetic field. The core is made mostly of the metals iron and nickel. It consists of two parts–a liquid outer core and a solid inner core. The movement of these layers over each other is what makes the Earth’s magnetic field.

Plate Tectonics

Plate Tectonics The Earths’ Magnetosphere

Plate Tectonics - Earth’s Interior Temperature Inside the Earth The graph shows how temperatures change between Earth’s surface and the bottom of the mantle. On this graph the temperature at the Earth’s surface is 0 o. C. Study the graph carefully and then answer the questions.

Plate Tectonics - Earth’s Interior Temperature Inside the Earth Reading Graphs: As you move from left to right on the x-axis, how does depth inside the Earth change? The depth increases.

Plate Tectonics - Earth’s Interior Temperature Inside the Earth Estimating: What is the temperature at the boundary between the lithosphere and the asthenosphere? About 1, 600 o. C

Plate Tectonics - Earth’s Interior Temperature Inside the Earth Estimating: What is the temperature at the boundary between the lower mantle and the core? About 3, 200 o. C

Plate Tectonics - Earth’s Interior Temperature Inside the Earth Interpreting Data: How does temperature change with depth in Earth’s interior? It generally increases with depth.

Plate Tectonics - Earth’s Interior Using Prior Knowledge Before you read, look at the section headings and visuals to see what this section is about. Then write what you know about Earth’s interior in a graphic organizer like the one below. As you read, write what you learn. What You Know 1. 2. 3. 4. 5. Earth’s crust is made of rock. Earth is very hot near the center. Dry land is part of the crust. The mantle is very hot. The core contains iron. What You Learned 1. 2. 3. 4. 5. Geologists use seismic waves to study Earth’s interior. Radioactive substances heat the interior of Earth. The crust is thickest under high mountains. The mantle is solid. Movements in the outer core create Earth’s magnetic field.

Plate Tectonics - Earth’s Interior Links on the Structure of Earth Click the Sci. Links button for links on the structure of Earth.

Plate Tectonics End of Section: Earth’s Interior

Plate Tectonics - Convection and the Mantle Types of Heat Transfer There are three types of heat transfer: radiation, conduction, and convection.

Plate Tectonics - Convection and the Mantle Convection Currents Heating and cooling of the fluid, changes in the fluid’s density, and the force of gravity combine to set convection currents in motion.

Plate Tectonics - Convection and the Mantle Convection Currents in Earth Heat from the core and the mantle itself causes convection currents in the mantle. This is believed to power Plate Tectonics - Video clip

Plate Tectonics - Convection and the Mantle Outlining An outline shows the relationship between major ideas and supporting ideas. As you read, make an outline about heat transfer. Use the red headings for the main topics and the blue headings for the subtopics. Convection and the Mantle I. Types of Heat Transfer A. Radiation B. Conduction C. Convection II. Convection Currents III. Convection in Earth’s Mantle

Plate Tectonics - Convection and the Mantle More on Convection Currents in the Mantle Click the PHSchool. com button for an activity about convection currents in the mantle.

Plate Tectonics - Convection and the Mantle Convection Click the Video button to watch a movie about mantle convections.

Plate Tectonics End of Section: Convection and the Mantle

Plate Tectonics - Drifting Continents Continental Drift Wegener’s hypothesis was that all the continents were once joined together in a single landmass.

Plate Tectonics - Drifting Continents Evidence for Continental Drift Fossils and rocks found on different continents provide evidence that Earth’s landmasses once were joined together in the supercontinent Pangaea.

Plate Tectonics - Drifting Continents Evidence for Continental Drift Fossils and rocks found on different continents provide evidence that Earth’s landmasses once were joined together in the supercontinent Pangaea.

Plate Tectonics - Drifting Continents Identifying Supporting Evidence As you read, identify the evidence that supports the hypothesis of continental drift. Write the evidence in a graphic organizer like the one below. Evidence Shape of continents Hypothesis Earth’s continents have moved. Fossils Climate change

Plate Tectonics - Drifting Continents Links on Continental Drift Click the Sci. Links button for links on continental drift.

Plate Tectonics End of Section: Drifting Continents

Plate Tectonics - Sea-Floor Spreading Mid-Ocean Ridges The East Pacific Rise is just one of the many mid-ocean ridges that wind beneath Earth’s oceans.

Plate Tectonics - Sea-Floor Spreading What Is Sea-Floor Spreading? In sea-floor spreading, the sea floor spreads apart along both sides of a mid-ocean ridge as new crust is added. As a result, the ocean floors move like conveyor belts, carrying the continents along with them.

Plate Tectonics - Sea-Floor Spreading Evidence for Sea-Floor Spreading Several types of evidence supported Hess’s theory of sea-floor spreading: eruptions of molten material, magnetic stripes in the rock of the ocean floor, and the ages of the rocks themselves.

Plate Tectonics - Sea-Floor Spreading Subduction at Trenches In a process taking tens of millions of years, part of the ocean floor sinks back into the mantle through deep-ocean trenches. (where is the oldest rock found? )

Plate Tectonics - Sea-Floor Spreading Growing an Ocean Because of sea-floor spreading, the distance between Europe and North America is increasing by a few centimeters per year.

Plate Tectonics - Sea-Floor Spreading Sequencing Make a flowchart to show the process of sea-floor spreading. Magma erupts along mid-ocean ridge. Magma cools to form new sea floor. Sea floor spreads away from ridge.

Plate Tectonics - Sea-Floor Spreading More on Sea-Floor Spreading Click the PHSchool. com button for an activity about sea-floor spreading.

Plate Tectonics - Sea-Floor Spreading Click the Video button to watch a movie about sea-floor spreading.

Plate Tectonics End of Section: Sea-Floor Spreading

Plate Tectonics - Theory of Plate Tectonics How Plates Move The theory of plate tectonics explains the formation, movement, and subduction of Earth’s plates.

Plate Tectonics - Theory of Plate Tectonics Plate Boundaries There are three kinds of plate boundaries: divergent boundaries, convergent boundaries, and transform boundaries. A different type of plate movement occurs along each type of boundary. Pages 34 and 35 in text.

Plate Tectonics - Theory of Plate Tectonics Calculating a Rate To calculate the rate of plate motion, divide the distance the plate moves by the time it takes to move that distance. Rate = distance/time For example, a plate takes two million years to move 156 km. Calculate its rate of motion. 156 km/2, 000 years = 7. 8 cm per year Practice Problem The Pacific plate is sliding past the North American plate. It has take ten million years for the plate to move 600 km. What is the Pacific plate’s rate of motion? 60, 000 cm ÷ 10, 000 years = 6 cm/yr

Plate Tectonics - Theory of Plate Tectonics Continental Drift It has taken the continents about 225 million years since the breakup of Pangaea to move to their present locations.

Plate Tectonics - Theory of Plate Tectonics Continental Drift Activity Click the Active Art button to open a browser window and access Active Art about continental drift.

Plate Tectonics - Theory of Plate Tectonics Building Vocabulary A definition states the meaning of a word or phrase by telling about its most important feature or function. After you read the section, reread the paragraphs that contain definitions of Key Terms. Use all the information you have learned to write a definition of each Key Term in your own words. Key Terms: Examples: plate divergent boundary The place lithosphere whereistwo broken plates into move separate apart, sections or diverge, called is plates. a divergent boundary. called scientific rift valley theory A scientific well-tested concept A deep valleytheory calledisa arift valley forms alongthat the explains wide range of observations. divergentaboundary. The theory of plate tectonics states that pieces of The place where two plates come together, or Earth’s lithosphere are in slow, constant motion, driven converge, is called a convergent boundary. by convection currents in the mantle. A transform boundary is a place where rocks two plates Faults are breaks in Earth’s crust where have slip past each other, moving in opposite directions. slipped other. plate tectonics convergent boundary transform boundary fault

Plate Tectonics End of Section: Theory of Plate Tectonics

Plate Tectonics Graphic Organizer Type of Plate Boundary Type of Motion Effect on Crust Feature(s) Formed Transform boundary Plates slide past each other. Crust is sheared. Strike-slip fault Convergent boundary Plates move together. Subduction or mountain building Mountains, volcanoes Divergent boundary Plates move apart. Crust pulled apart by tension forces. Mid-ocean ridge, ocean floor

Plate Tectonics End of Section: Graphic Organizer