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glacial striations continental drift

The continuity of glaciers, inferred from oriented glacial striations and deposits called tillites, suggested the existence of the supercontinent of Gondwana, which became a central element of the concept of continental drift. This aided Wegener’s theory that the continents were once all joined as a single landmass. The White Cliffs of Dover) and coal, and these only forms in warm, shallow seas. Glacial striations on rocks show that glaciers moved from Africa toward the Atlantic Ocean and from the Atlantic Ocean onto South America. His work disproved Wegner's proposal that the shelf was a permant feature that could better be used to show the fit of the continents. There are belts of rock in Africa and South America that match when the ends of the continents are joined. With continents in their present positions, the till deposits do indicate erratic glacier motion. In his time, Alfred Wegner (1880–1930) was known for his work in meteorology and polar research, but today he is best remembered for his additions to the development of continental drift theory. Wegener suggested that the poles remained stationary and that the continents changed their positions relative to the poles, which we know know is not accurate (actually, both the continents and poles continuously shift in position). After huge contributions from several pioneers over the last century, all the evidence suggests that the theory of Plate Tectonics and continental drift is accurate. Discuss the particles deposited by glaciers as they advance and recede. However, Wegener deduced that the continents must have once been connected in a single super continent (Pangaea), and from this mass the continents drifted apart. From this he found that continents showed evidence of experiencing many climates. However, would you believe if someone told you that these broken land masses were once connected to each other as one huge supercontinent? Along with new evidence gathered from his own studies, Wegener also included all previous evidence that the continents had drifted. Furthermore, the Cape Fold Belt of South Africa aligned perfectly with mountain ranges in South America. These enormous portions of land, which would spontaneously rise and fall out of the ocean floor, were suggested to exist long enough to that they gave flora and fauna enough time to move around the globe. Most of it was personal but (he wasn’t a geologist, challenging scientific consensus, etc.). Wikipedia. False. This also applied to fossil records, including the fresh-water reptile, Mesosaurus (found across South Africa and southern South America), the land reptile Lystrosaurus (found in a band across current India, Antarctica, and central Africa). He found two things. Glacial striations (grooves) Glacial deposits "Dwyka Tillite" Correlation of fossil flora and fauna "Ecca Beds" - Glossopteris flora Based on the striations, it also appeared that the ice came from the oceans and moved onto the land which is not possible. The outward movement of magma underneath the lithosphere effectively ‘pushes’ it outwards – expanding the oceans. The first truly detailed and comprehensive theory of continental drift was proposed in 1912 by Alfred Wegener, a German meteorologist.Bringing together a large mass of geologic and paleontological data, Wegener postulated that throughout most of geologic time there was only one continent, which he called … Figure 5. Therefore, Hess’s model of the reasoning behind continental drift was more easily accepted. These findings completely supported Hess’ theory that the oceanic lithosphere is created at mid ocean ridges, and then split in half and moved outwards. As they drag along they scratch the underlying surface creating grooves parallel to the direction of travel of the glacier. There is also much climate evidence supporting continental drift, most notable of which is glacial activity. This means that the Earth’s magnetic field moves over long periods of time, or completely reverses its direction at different intervals. The continuity of glaciers, inferred from oriented glacial striations and deposits called tillites, suggested the existence of the supercontinent of Gondwana, which became a central element of the concept of continental drift. During the last glacial period more than 50 million square kilometers of land surface were geomorphically influenced by the presence of glaciers. As Figure 5 shows, when Pangaea is reconstructed it shows that these continents were once further south. Wegener’s last contribution was just before his death, in which he found that shallower oceans were younger. Mr. Clauss Recommended for you. In proposing the theory of continental drift, Alfred Wegener relied on evidence from the shape of the continents, the distribution of plants and animals, similarities between landscapes, contiguous veins of ore that ran between continents, and the distribution of glacial deposits. Theory of Continental drift In 1915, the German geologist and meteorologist Alfred Wegener first proposed the theory of continental drift, which states that parts of the Earth's crust slowly drift atop a liquid core. However Wegener pointed out that rather than using the coastline, geologist should look at the continental slope. Diagram showing ancient glacial evidence used to support the theory of continental drift. At the ridges, hot magma rises up after being heated by the core. As many did before him, Wegener also used the apparent puzzle-like fit of the continents as proof that continents had once been joined. Very soon after, new findings were published that further reinforced Hess’ ‘sea floor spreading’. "Alfred Wegener." The cooling also caused contraction and the pressure produced by contraction caused some pa… Sea-Floor spreading. At the crust, it hardens and becomes the newest part of the sea floor. The fossil record supports and gives credence to the theories of continental drift and plate tectonics. Critics of this evidence simply claimed that being a marine reptile, mesosaurus could simply swim to the other coast. We can find lots of limestone (e.g. As the ice in a valley glacier moves from the area of accumulation to that of ablation, it … What is the Evidence for Continental Drift? Glacial drift definition, material, as gravel, sand, or clay, transported and deposited by a glacier or by glacial meltwater. Exotic Terraines (micro-plate tectonics) A. CONTINENTAL DRIFT (Wegener) Jigsaw puzzle effect of South America and Africa. Paleomagnetism is based on the idea of ‘polar wandering’ and ‘polar switching’. Evidence for continental drift is also found in the types of rocks on continents. He noticed that, at the continental shelves, all the large Earth masses fit nearly perfectly. He also plotted on the map the orientation of glacial striations. Second, he discovered that (conversely) the deepest parts of the ocean were actually very close to continental margins in the Pacific. But geologists have found no evidence of glacial action in the northern hemisphere at this time, and instead say the climate was warm and even tropical. Glacial striations on South America, Africa, Australia, Antarctica and India suggests that these continents were joined (Figure 2) during the periods of time that they were glaciated, since glaciers extend between continents dseparated by large expanses of water. Some distinctive fossils found on the southern continents indicate that they came from one ancient single continent. At the time, some of the most prominent theories were that species evolved independently from one another, or that they swam across oceans to get to their current locations. Set forth in 1912 by Alfred Wegener, a geophysicist, and meteorologist, continental drift also explained why look-alike animal and plant fossils, and related rock formations, are found on different continents. Tags: Question 12 . Their ability to erode soil and rock, transport sediment, and deposit sediment is extraordinary. Glacial striations (scratches) and erratics (rocks moved away by glacial ice from original bedrock) correspond between continents. He presented his ideas to the German Geological Association in 1912, and wrote a book titled ‘The Origin on Continents and Oceans’ in 1915. In particular, the English geologist Arthur Holmes proposed in 1920 that plate junctions might lie beneath the sea, and in 1928 that convection currents within the mantle might be the driving force. However, if this were true, mesosaurus fossils should be found up and down the coasts, not limited to one specific area. See more. Evidence later accumulated from other areas of research, but the theory was not taken seriously until well after Wegener's death. When the magma cools and hardens into the basalt ocean floor, it acts as a record, preserving the direction and latitude of poles at that time. Vine was actually a PhD student under Matthews at the time of their research. Photo by Tom Biggs. These glacial grooves are part of the Glacial Grooves State Monument located on Kelleys … By comparing the fit of continents at this edge Wegener showed and even better fit than before. Glacial Striations are left when large boulders are dragged beneath glaciers. Wegener had said that the continents pushed through the ocean floor as they moved, which was deemed impossible by critics. SURVEY . Unlike the shorlines the margin of the continental slope is not determined by sea level changes and is unaffected by coastal erosion; it is the true edge of the continent. Wegener went on several expeditions on both sides of the Atlantic Ocean to analyze rock type and fossil distribution, and he found a very significant ‘matching’ between the East and West sides of the Atlantic Ocean. Student under Matthews at the South pole, these striations line up with each other one! Magnetic field moves over long periods of time, or clay, transported and deposited by a glacier or glacial... Deepest parts of the associated phenomena single landmass idea is know known the., new findings were published that further reinforced Hess’ ‘sea floor spreading’ theory used to explain the of! By critics other areas of research, but the theory was the that. One specific area landscapes in the middle and high latitudes and in alpine environments geologist challenging! 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