THEORY OF CONTINENTAL DRIFT Page 6 THEORY OF CONTINENTAL DRIFT Proposed by Alfred Wegener in 1910 States approximately 200 million years ago (m.y.a.) all the continents existed as 1 large landmass He called this landmass Pangea, meaning all land (supercontinent) Wegener said the continents were moving away from one another by flowing through the oceans Problem: he not say why or try to describe the mechanism for the movement Show DVD 100 Greatest Discoveries in ES

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Evidence of Continental Drift Page 6 Evidence of Continental Drift Coastlines of the continents fit like pieces of a giant _______________ For examples, ______________ fits well with the west coast of _______________ jig-saw puzzle South America Africa

Page 6 2. Fossil Clues- certain fossils of ancient life forms are found on widely separated continents. For example, Mesosaurus- was a small freshwater reptile. It’s fossils are found in ________ and ______________ Map Key Africa S. America

Page 6 Add Map Key Symbol for Mesosaurus

Another example Glossopteris- It was an ancient seed-fern (with very large heavy seeds). It’s fossils are found in _______, ________ ___________, __________ and ____________ Page 6 India Africa Australia Antarctica S. America Map Key

Page 6 Add Map Key Symbol for Glossopteris

Appalachian Page 6 3. Rocks Clues a. The _____________ Mountains of the eastern US are geologically similar to the mountains in Greenland and western Europe, which include Caledonian Mountains of Scotland. Appalachian Map Key

Page 6 3. Rocks Clues Add Map Key Symbol for Mountains

Page 6 3. Rocks Clues Structure, age, and mineral content of rocks are similar on the coasts of eastern ____________ and western ________ S. America Africa Map Key

Page 6 3. Rocks Clues Add Map Key Symbol for Rock Structure

Page 6 4. Climate Clues- Coal, which forms from plants that grow in warm swampy environments, is found today in the colder climates of ______________ and ______________ Map Key Antarctica N. America

Page 6 4. Climate Clues Add Map Key Symbol for Coal Deposits

Page 6 4. Climate Clues Coral limestone, containing the remains of coral, which once lived in warm seas, is found today in northern latitudes such as ____________ N.Y.S. Map Key

Page 6 Add Map Key Symbol for Coral limestone 4. Climate Clues

Questions Page 6 2 b/c climates were once tropical when these continents were close together

Page 6 Add Map Key Symbol for Ancient Rock Formations

Plate Tectonics asthenosphere The theory of Plate Tectonics Page 7 The theory of Plate Tectonics states that the Earth’s crust is divided into sections called _____________ (crust + upper mantle) The theory of Plate Tectonics states that these lithospheric plates are in motion and they “float” or ride on the ________________. Lithospheric plates asthenosphere

Evidence Distribution of Earthquakes, volcanoes, & mountain ranges Page 7 Distribution of Earthquakes, volcanoes, & mountain ranges

Page 7 Earthquakes, volcanoes, & mountain ranges seem to fit a pattern that outlines the major plate boundaries Crustal activities occurs at plate boundaries

Major Lithospheric Plates Page 7 Major Lithospheric Plates ______________ 5. ______________ ______________ 6. ______________ ______________ 7. ______________ ______________ 8. ______________ Pacific North American Nazca South American Eurasian Antarctic African Indian

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Plate boundaries Pacific Plate Ring of Fire Page 7 Most volcanoes & earthquakes occur at _____________________________ The most active sites border the _____________ in an area called the ______________________________ Plate boundaries Pacific Plate Ring of Fire

Questions Page 7 2 4