Chapter 5; Section 3 Drifting Continents

Question… Do you see the pieces of the jigsaw- puzzle?

You and a partner will have 5 minutes to complete the puzzle… You and a partner will have 5 minutes to complete the puzzle…

Here’s what to do… 1. Cut it up! Cut out each puzzle piece; cutting as close to the lines as possible (it doesn’t have to be perfect). 2. What’s the code? Use the legend to identify the symbols on each island or continent. 3. Puzzle me this. Look at the shapes of continents and islands. What landmasses seem to fit together? 4. Let’s ROCK! Examine the evidence and try to match up landmass boundaries that show similar rock strata, fossilized desert belts, and dinosaur fossils. 5. Hold that Pose! Look over the arrangement of the continents and islands and decide if the position of any of them should change. When you are satisfied with your map of Pangaea, glue it down on the world map.

1700’s – geologists thought that the continents had always remained in the same place 1700’s – geologists thought that the continents had always remained in the same place Early 1900’s – Alfred Wegener (VAY guh nur) thought continents could have once been joined together as one landmass Early 1900’s – Alfred Wegener (VAY guh nur) thought continents could have once been joined together as one landmass

Wegener hypothesized… All continents were once joined together in a single landmass and have since drifted apart All continents were once joined together in a single landmass and have since drifted apart –This idea became know as continental drift

According to Wegener… Continents drifted together to form Pangaea (the supercontinent) Continents drifted together to form Pangaea (the supercontinent) –Means “all lands” –Existed about 300 million years ago Over 10’s of millions of years ago, Pangaea began to break apart Over 10’s of millions of years ago, Pangaea began to break apart –Continents slowly moved to positions they are today

Wegener gathered evidence… From different areas in science to support his ideas From different areas in science to support his ideas –Land features –Fossils –Climate change

Evidence from Land Features… Mountains of Africa & S. America lined up Mountains of Africa & S. America lined up European coal fields matched up with fields in N. America European coal fields matched up with fields in N. America

Evidence from Fossils… Fossil – any trace of an ancient organism that has been preserved in rock Fossil – any trace of an ancient organism that has been preserved in rock –Glossopteris ( glaw SAHP tuh ris) found in rocks in Africa, S. America, Australia, India, & Antarctica –Mesosaurus & Lystrosaurus (fresh water reptiles) found on different continents

Evidence from Climate… As continent moves toward equator, climate becomes warmer As continent moves toward equator, climate becomes warmer As continent moves toward poles, climate becomes colder As continent moves toward poles, climate becomes colder Continents carry with it fossils and rocks formed at old location Continents carry with it fossils and rocks formed at old location

Evidence from Climate cont… Example… Example… –Fossils of tropical plants found on island in Arctic Ocean –Deep scratches in rocks show glaciers covered S. Africa (too warm for this to happen today)

Wegener’s Hypothesis…. Wegener suggested continents plowed across ocean floors Wegener suggested continents plowed across ocean floors

Wegener could not provide a satisfactory explanation for the force that pushes or pulls the continents Wegener could not provide a satisfactory explanation for the force that pushes or pulls the continents Could not identify cause of continental drift so… Could not identify cause of continental drift so…