Continental Drift and Supporting Evidence

Continental Drift Hypothesis

• Proposed by Alfred Wegener: Investigated if continents moved over time.

• Supercontinent Pangaea: All continents were once part of Pangaea, which broke apart over time.

• Continental Drift Hypothesis: Continents are in constant motion on Earth’s surface.

Evidence Supporting the Hypothesis

Rock Formations

• Similar rock formations across Australia, South America, Africa, India, and Antarctica.

• Identical volcanic rocks found in western Africa and eastern South America.

• Similarities in age and structure between the Caledonian and Appalachian mountain ranges.

Glacial Features

• Evidence of glacial grooves and sediments on continents near the South Pole 290 million years ago.

• Ice sheets suggested to have covered parts of South America, Africa, India, and Australia when Pangaea existed.

Fossils

• Similar fossils of the plant Glossopteris discovered on South America, Africa, India, Antarctica, and Australia.

• Fossil distribution indicates that these continents were once joined, as the plant's heavy seeds could not cross oceans.

Skepticism About Wegener's Hypothesis

• Slow movement: Continental drift is gradual; measurements of movement were not available.

• Lack of explanation: Unable to explain the forces causing continental movement through solid rock.

• Vital evidence on seafloor only discovered after Wegener's death (1930).