Continental Drift

Looking at your Pangaea Puzzles… What did you discover?

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

Wegener hypothesized… 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) Means “all lands” Existed about 300 million years ago 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 Land features Fossils Climate change

Evidence from Land Features… Mountains of Africa & S. America lined up 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 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 poles, climate becomes colder Continents carry with it fossils and rocks formed at old location

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