WEGENER’S HYPOTHESIS
• Alfred Wegener was a German scientist
• Proposed his hypothesis of continental drift that stated,
that the continents had once been joined to form a single
supercontinent called Pangaea (1915)
• Pangaea means all land
• Wegener also hypothesized that around 200 million years
ago Pangaea begin to break into smaller continents and
drifted to their current positions today
EVIDENCE
• Similarity between the shorelines on the opposite sides of
the coast
• Fossil evidence for continental drift includes several fossil
organisms found on different landmasses
• Wegener argued that the organisms couldn’t cross the
present day ocean
• Land bridges were a thought, but if that were the case the
fossils would still be on the sea floor
EVIDENCE CONTINUED…
• Rock evidence for continental drift exists in the way of
several mountain belts that end at one shoreline, that then
reappears on a landmass across the ocean
• If Pangaea occurred then matching rock types and
mountain belts should be seen in both present day
landmasses
• Like a puzzle
NEW THEORY…PLATE TECTONICS
• New data on earthquakes and the Earth’s magnetic field
led to new beliefs
• 1968 Plate Tectonics
• Provides outline for understanding most geological
processes. (example – mountain formation)