![]() If the continents haven’t moved, then this would suggest an ice sheet extended from the south pole to the equator at this time – which is unlikely… if the continents of the southern hemisphere are re-assembled near the south pole, then the Permo-Carboniferous ice sheet assumes a much more reasonable size. * Glacial Deposits : Today, glacial deposits formed 300 million years ago are found in Antarctica, Africa, South America, India and Australia. When these land masses are re-assembled the mountain belt forms a continuous linear feature. Pieces of the Caledonian fold mountain belt are found in Greenland, Canada, Ireland, England, Scotland and Scandinavia. * Tectonic Fit : Fragments of an old fold mountain belt between 450 and 400 million years ago are found on widely separated continents today. * Geological Fit : When the geology of eastern South America and West Africa was mapped it revealed that ancient rock outcrops (cratons) over 2,000 million years old were continuous from one continent to the other. The best fit is obtained if the coastlines are matched at a depth of 1,000 metres below current sea level. * Jigsaw Fit : The similarity in outline of the coastlines of eastern South America and West Africa had been noted for some time. The following text is from The Geological Society of London, website on plate tectonics. Wegener had begun the process of collecting evidence, but there was much more work to be done over the next 40 years. When one makes extraordinary claims, one must bring evidence to back them up. * It is the nature of science to be skeptical of extraordinary claims. Although today we know that Wegener was right that the continents do move, he did not know how they did so. what could possibly push an entire continent through the Earth’s crust?) * Wegener did propose a hypothesis about how continents could move, but he was incorrect about them. Why? * A plausible driving force was missing. Initial rejection of Wegener’s hypothesis Wegener’s theory of continental drift was not accepted for many years. Physical Science Concepts by Mason, Griffen, Merrill and ThorneĬlick to access C31.pdf Fossils exist in geographic patterns – this pattern implies that all of the continents must have once laid together.īased on this evidence, Wegener proposed that over time, the continents slowly moved like this: ConnollyĬontinental Drift Theory from jjconnolly “From Continental Drift to Plate Tectonics: The Evidence. It wasn’t until Alfred Wegener (1880-1930) came along that research really beganĮvidence for Continental drift, Slide show by J. So by the 1850s many geologists discarded the idea that continents could move. While the idea was intriguing, one couldn’t simply assume that it was true. Writing in 1889, Alfred Russel Wallace remarks “It was formerly a very general belief, even amongst geologists, that the great features of the earth’s surface, no less than the smaller ones, were subject to continual mutations, and that during the course of known geological time the continents and great oceans had again and again changed places with each other.” How could continents possibly move? Good question – and at the time no one knew of any plausible causal mechanism. ” After him, a number of other geologists made similar observations, up until the 1850s. ![]() The vestiges of the rupture reveal themselves, if someone brings forward a map of the world and considers carefully the coasts of the three. In the late 1500s Abraham Ortelius suggested that the Americas were “torn away from Europe and Africa … by earthquakes and floods…. This is where we build from.Īlfred Wegener discovers continental drift Building on what we already know Make connections to prior knowledge. Tier III: Low frequency, domain specific terms. Key to understanding directions & relationships, and for making inferences. Vocabulary objective Tier II: High frequency words used across content areas. Content objective: What are we learning and why are we learning this? C ontent, procedures, or skills.
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