Continental Drift

A Wegener

Alfred Wegener was a meteorologist that published the Theory of Continental Drift in 1915. He believed that the continents were once connected together in one supercontinent called Pangaea. This contradicted the
current idea that land bridges once connected the
continents. Land bridges have been proven not true.

Minute Earth Video Plate Tectonics Explained

EVIDENCE:
Wegener proposed several pieces of evidence to support his theory that the continents were once joined and somehow drifted apart.

Pangaea

  1. Shape:
    The shape of the shorelines of the continents fit together like puzzle pieces
  2. Fossils:
    Similar fossils are on different continents from plants and animals which would be unable to travel across the open oceans
  3. Rocks:
    Similar types and ages of rocks, minerals which were formed at the same time are found on different continents
  4. Mountain Ranges:
    Mountains ranges formed at the same time, and with the same type of rocks are found on different continents
  5. Climate:
    Glacial striations marks are found on different continents that match up
    Tropical fossils are found in the in theArtic and in Antarctica
    Coal (tropical formation) found in Antarctica

Fossil EvidencePangaea fossils

Mesosaurus: A reptile that only lives in freshwater, it would be unable to live in or swim across the Atlantic Ocean

Glossopteris: A fern that only grows in tropical climates but fossils are now found in cold climates like Antarctica.

Lystrosaurus: A land reptile that could not swim or live in the ocean to get from one continent to another.

Rock and Mountain Evidence

Rocks and minerals found in South America match up with rocks and minerals of the same age and composition in Africa, supporting that the continents were together when the rocks and mineral were made.

Caledonian and Appalachian Mountains: Both sets of mountains, the Caledonian in Northern Europe and the Appalachian in North America & Greenland were formed at the same time and are the same range but now separated by the Atlantic ocean.

Climate Evidence

Glacial Striations: Scratches that are left on bedrock from rocks trapped under a glacier and rubbed along the bedrock.

The scratches show the direction the glacier was moving and are found

Coal is found in Antartica, coal is an organic sedimentary rock that originates from tropical plants founded in the tropics. It is found in Antarctica proving the land was once in a tropical climate zone.

Rejection of Continental Drift

Wegener’s idea of continental drift was rejected by the scientific community because couldn’t explain how the continents could “drift” apart from one another. Wegener

There was no proof or explanation of how the continents moved. This is called the “Mechanics” of how the continents move.

Alfred Wegener died on an expedition to Greenland in 1930 at the age of 50 before the proof was discovered by Harry Hess and explained as Sea Floor Spreading.


Layers of the Earth