Presentation on theme: "C ONTINENTAL D RIFT What evidence do scientists have to support the fact that the Earths crust is continuously moving?"— Presentation transcript:
C ONTINENTAL D RIFT What evidence do scientists have to support the fact that the Earths crust is continuously moving?
1500 S – A BRAHAM O RTELIUS 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
1800 S – E DUARD S UESS Stated that the southern continents were once a single landmass called Gondwanaland Northern continents called Laurasia
1900 S – A LFRED W EGENER Continental Drift Hypothesis that Earths continents were joined as a single landmass that broke apart about 200 million years ago (mya) Known as Pangaea Continents slowly moved to their present locations
P ANGAEA - A LL E ARTH
E VIDENCE FROM F OSSILS 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
E VIDENCE FROM R OCK F ORMATIONS Similarly, rock formations are similar on distant continents For example, rock types found in Appalachian Mountains similar to those found in Greenland and Europe
C LIMATIC E VIDENCE 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
F LAWS IN C ONTINENTAL D RIFT T HEORY Wegeners 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
R EVIEW Q UESTIONS 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?