World ExplorationsWorld Explorations

• By 1570, European explorers had mapped most of the Earth. People looked at these maps and began to notice, what?

WegenerWegener

Alfred Wegener born in Germany

Earned a Ph D. in Astronomy, 1904

Interested in geophysics

1911, found a scientific paper listing identical fossils on opposite side of the Atlantic, land bridges

Looked for examples, additional evidence

Took all his findings & wrote a book.

Published in 1915

The Theory of Continental The Theory of Continental DriftDrift

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

Evidence to Support the TheoryEvidence to Support the Theory

EVIDENCE WEGENER USED TO EVIDENCE WEGENER USED TO SUPPORT CONTINENTAL DRIFTSUPPORT CONTINENTAL DRIFT

Natural Fit

Fossils

Rocks

Climate Changes

““Puzzle Pieces”Puzzle Pieces”

• Continents look like they could be part of a giant jigsaw puzzle

Distribution of FossilsDistribution of Fossils

• Plant and animal fossils found on the coastlines of different continents

• No evidence of a land bridge

Sequence of RocksSequence of Rocks

• Same rock patterns found in North America and Scotland

• South America, India, Africa, Antarctica and Australia

• Form continuous chain

Ancient ClimatesAncient Climates

• Tropical plant remains (coal deposits) found in Antarctica

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

Problems With The TheoryProblems With The Theory

• No mechanism for movement of continents

• Wind and currents could possibly move fossils

• Theory was not accepted by scientists