The Theory of Continental The Theory of Continental DriftDrift

Homework: Complete puzzle and “position” Paper (1 full pg).Due Monday, March 3

Continental Drift TheoryContinental Drift Theory

• Proposed by Alfred Wegener in 1912

• 250 million years ago, all of the continents were combined into one super-continent called “Pangaea”

• The continents gradually drifted apart to where they are today

Video LinkVideo Link

• Alfred Wegener clip

Evidence of Continental DriftEvidence of Continental Drift

Puzzle Pieces• Continents look like

they could be part of a giant jigsaw puzzle

• Continental shelves

of Africa and South America fit together almost perfectly

Distribution of FossilsDistribution of Fossils• The Fossil Record

– Glossopteris remains found in SA, Australia, Asia, and Africa, & Antarctica

– Fossils of deciduous trees found near North Pole

– Coal formation in many parts of the world, but needed to be swampy marshes with lots of rain near the equator

The EvidenceThe Evidence

• Fossil Evidence

The EvidenceThe Evidence

• Fossil Evidence

Sequence of Rock TypesSequence of Rock Types• The Rock Record• Rocks in Argentina

identical to ones in Africa• Diamond rich rocks in

South Africa match rocks in Brazil

• Coal beds in NA, Britain, and Belgium same

• Red sandstone same in NA, Greenland, Britain, Norway

The EvidenceThe Evidence

Mountain Ranges

Ancient ClimatesAncient Climates

• Tropical plant remains (coal deposits) found in Antarctica

• Glaciation in Africa, South America, India, and Australia during the same time

The EvidenceThe Evidence

• Climatic Evidence– Glacial evidence

Theory of Continental DriftTheory of Continental Drift

• Vocabulary– Continental shelf – part of a continent that

extends under shallow water from the ocean’s edge to the steeper sea floor slope.

– Pangaea- all land– Panthalassa – all seas– Theory of Continental Drift – continents were

once one landmass that broke apart and moved to present locations.

Evidence of Continental DriftEvidence of Continental Drift

• 1.

• 2.

• 3.

• 4.

Evidence of Continental DriftEvidence of Continental Drift

• 1. Puzzle Pieces – continents fit together like a giant puzzle – esp. SA and Africa

• 2. Fossil Record – the same plants, trees, and animals and coal beds occur in different continents

• 3. Rock Record – same sequence of rock occurs on different continents, same mountain ranges occur on different continents

• 4. Climate – same glaciation marks on different continents, fossil indicate tropical climates where now cold.

PangaeaPangaea