A Planet on the Move Geological Processes of Earth By Jeff Pathfinder Heritage Intermediate School 6th Grade

Objectives Describe how the continents have moved over the past 250 billion years. Provide support for these theories. Explain the effects of this movement on the Earth’s surface.

Introduction Study the shapes of the continents closely while looking at a globe or map of the world. Do you notice anything about the continents on opposite sides of the Atlantic Ocean?

Continental Drift Alfred Wegener did! A German geologist, Wegener proposed the theory of continental drift. He calculated that 200 million years ago the continents were originally joined together, forming a large super continent. He named this super continent Pangaea, meaning "All-earth".

Evidence... Same type of rocks on each continent. Same type fossils on each continent.

Seafloor Spreading In the 1950’s scientists began to look at the ocean floor for evidence of this movement. They noticed deep sea trenches and rifts. Age Evidence and Magnetic Clues provided further evidence that Wegner had been correct!

Plate Tectonics In the 1960’s scientists theorized Plate Tectonics. Earth is made of 10 plates that “slide” around on the plastic-like layer of the earth below the crust called the asthenosphere.

Plate Movement Convergent Divergent Transform another…earthquakes

Convergent Plates collide…volcanoes, mountains

Divergent Copywrite 1999 John Wiley and Sons, Inc. Plates move apart…ridges, rift valleys

Transform Plates slide past one another…earthquakes! Copywrite 1999 John Wiley and Sons, Inc.

Do You Remember? 1. Define Pangaea. 2. Describe Wagner’s theory. 3. What evidence is there of Seafloor Spreading? 4. Describe Plate Tectonics. 5. Name and describe the 3 Plate Boundaries.

Works Cited Earth Science, Glencoe/ McGraw Hill. Columbus, Ohio, 2001 Research and images, understanding.html Copywrite 1999 John Wiley and Sons, Inc.