Continental Drift Theory PDF

▪ PANGAEA ▪ EVIDENCES OF PLATE MOVEMENTS What plates the green and orange color represents?  Some early ideas In 1858, an American, A. Snider published an article on the origin of the Americas He thought that South America and Africa were once together Snider proposed that a hug...

▪ PANGAEA ▪ EVIDENCES OF PLATE MOVEMENTS What plates the green and orange color represents?  Some early ideas In 1858, an American, A. Snider published an article on the origin of the Americas He thought that South America and Africa were once together Snider proposed that a huge volcanic event caused the landmass to split  Half a century later…this idea continued as continental drift In 1910, an American, F.B. Taylor, discussed the origin of mountains He explained that continental movements that ended in collisions would cause the formation of mountains  More scientist joined in… Alfred Wegener Alfred Lothar Wegener (nov, 1, 1880 - 1930) was a German polar researcher, geophysicist and meteorologist. He is most remembered as the original theorist of the theory of continental drift by hypothesizing that the continents are slowly drifting around the Earth.  More scientist joined in… Alfred Wegener Alfred Wegener published The Origin of Continents and Oceans He proposed that the continents had once been joined together in a supercontinent he called Pangaea  What’s in a name? The word Pangaea comes from Greek words “pan” and “gaia” “pan” meaning “entire” “gaia” meaning “earth” Therefore Pangaea literally means “Entire Earth.” Which seems fitting because it was composed of every land mass on the entire Earth!  PANTHALASSA Since all the continents were joined in one land mass called PANGAEA, the remaining area of our earth was covered in ocean! “pan” meaning “entire” “thalassa” meaning “sea” This ocean is referred to as, PANTHALASSA.  What is Pangaea? Pangaea is a super continent that is said to have existed from the Permian through the Jurassic period in our earth’s history. EVOLUTION OF PANGAEA  So…what happened to Pangaea? About 200 million years ago Pangaea existed Dinosaurs roamed over the land TRIASSIC PERIOD  JURASSIC PERIOD The Jurassic Period was the North America second segment of Eurasia the Mesozoic Era. It Africa occurred from 199.6 to 145.5 South America million years ago, Antartica following the Triassic Period and preceding the Cretaceous Period.  CRETACEOUS PERIOD The Cretaceous Period was the last and longest segment of the Mesozoic Era. It lasted approximately 79 million years, from the minor extinction event that closed the Jurassic Period about 145.5 million years ago to the Cretaceous- Paleogene extinction event dated at 65.5 million years ago. PRESENT  Most of his colleagues didn’t agree with him. He couldn’t explain why the continents did not seem to be moving now But his evidence had him convinced of his theory.  Evidence of Plate Movements German scientist Alfred Wegener proposed evidence to back up his continental drift theory, but his claims were initially rejected. About half a century of his death, improvements in science and technology validated his claims.  Evidence of Plate Movements Comparison Between Wegener’s and Modern Science’s Ideas on Tectonic Plates Wegener’s Idea Science Today The eastern coastline of South The shapes of several continents seem America and Western coastline of to fit into each other Africa seem to fit snugly into each other Rock types and fossils in south Similar fossils of plants and animals were found on the America and south Africa are very eastern coast of south America similar in terms of their sequence and on the western coast of and age up to about 200 million years ago, after which their some parts in the african sequences diverge as the continent continents parted. Animal in South America share common ancestors those in Africa Evidence of Plate Movements  Evidence of Plate Movements There are other cases of similar fossil Mountain ranges of different sequences from landmasses on the continents are made of the same eastern and western coasts of other rocks, were formed in the same oceans. sequence, and are of the same age; but are now far apart form each other. The sequence of rock layers on Geological studies of areas with opposite sides of oceans match each glaciers in eastern south America other. match those in south and west Africa. Fossils or tropical plants were also Coal from hot swampy forests and found in the arctic and Antarctic polar coral limestone from warm shallow regions seas can be found in northern countries like Scotland and even in Antarctica near the south pole. Summary of the Lesson: Socratic Strategy