ContinentalContinental

CH 4 Prentice Hallp.118-122

CH 4 Prentice Hallp.118-122

DriftDrift

• Proposed a super continent he called Pangaea (“All Earth”)

• Proposed his hypothesis of continental drift– Wrote the Origins of the

Continents & Oceans 1915.

Alfred Wegener

Layers of

Earth Menu

• All continents were once together and have slowly drifted over time to their current locations.– Pieces of Evidence:

Continental Drift

Fit of the Continents

Landforms Climatic Evidence

Fossil Evidence

World Map/ CD Evidence

• The coast of S. America and Africa fit together like a puzzle

• 1700’s thought the continents remained fixed

• 1900’s started to think a new way.

Fit of the Continents

CD RiftEvidence

Landforms• Mountain features & other features– South African Mt. ranges line up with a mountain

range in Argentina– European coal fields line up with coal fields of

North America.

CD RiftEvidence

• A trace of an organism preserved in rock– Mesosaurus and Lystrosaurus: reptiles that could

not swim across a salty ocean– Found in places now separated by oceans which

suggest that the continents were connected.

Fossils

CD RiftEvidence

• Glossopteris: a tropical fernlike plant– Found in cooler climates of today, suggest that

the continents have since moved– Seeds were too large to be carried by wind.

Fossils

CD RiftEvidence

• Fossils of tropical plants were found on the island of Spitsbergen, which is in the Arctic Ocean– A harsh polar climate covered

with ice– 300 million years ago, the

island had a warm and mild climate

– Wegener believed it was closer to the equator.

ClimateClimate

• Glacial Evidence found as deep scratches in rocks on South Africa– The climate of S. Africa today is too mild– Suggests that S. Africa was closer to the S. Pole

Climate

• Wegener believed that the climates changed because the position of these places changed– The continent carries the fossil and rock evidence

from where it formed and provide evidence for CD.

Climate

CD RiftEvidence

Rejected?

• Wegener could not provide a satisfactory explanation for the force that pushes or pulls the continents– Geologists rejected his idea until the 1960’s

CD RiftEvidence