C ONTINENTAL D RIFT What evidence do scientists have to support the fact that the Earths crust is...

CONTINENTAL DRIFTWhat evidence do scientists have to support the fact that the Earth’s crust is continuously moving?

1500S – ABRAHAM ORTELIUS

Saw that the coastlines of Africa and the Americas looked similar

Concluded they must have once fit together

Broke apart due to floods, earthquakes and volcanoes

1800S – EDUARD SUESS

Stated that the southern continents were once a single landmass called Gondwanaland

Northern continents called Laurasia

1900S – ALFRED WEGENER Continental Drift

Hypothesis that Earth’s continents were joined as a single landmass that broke apart about 200 million years ago (mya)

Known as PangaeaContinents slowly

moved to their present locations

PANGAEA - ALL EARTH

EVIDENCE FROM FOSSILS

Similar fossils of several different plants and animals that once lived near each other found on widely separated continents

Land animals did not swim across ocean, so there had to be a land connection between continents

EVIDENCE FROM ROCK FORMATIONS

Similarly, rock formations are similar on distant continents

For example, rock types found in Appalachian Mountains similar to those found in Greenland and Europe

CLIMATIC EVIDENCE

Coal deposits in Antarctica indicate that the climate was much warmer in the past

Must have been located closer to the equator before it drifted

FLAWS IN CONTINENTAL DRIFT THEORY

Wegener’s theory of continental drift had some notable flaws:Not able to explain what force was large

enough to move such large pieces of earth over great distances

Not able to explain how the ocean basins were not shattered, despite solid landmasses crossing through them

REVIEW QUESTIONS What does Pangaea mean in Greek? What was Ortelius’ contribution to

Continental Drift? Who is credited with the theory of

Continental Drift? List and describe the three main evidences

for Continental Drift. What is one major flaw in the theory of

Continental Drift?