Plate Tectonics Essays - Plate Tectonics, Continental Drift

Plate Tectonics Plate Tectonics Since the beginning of human kind there has been a cloud of wonder regarding the origin of our planet. Scientist interested in this field through out the years have developed many different theories to how our planet came about. Before the Twentieth Century, scientist and geologist alike revolved in the idea that Mountain building was due to the massive contractions of the earth caused by the gradual cooling of molten rocks. In 1900, American scientist Joseph Le Conte, published an article in the Appleton's Popular Scientific Monthly. He described that the problem in understanding mountain building was establishing the cause of sideways pressure. ?The most obvious and as yet the most probable view is that it is the result of the secular contraction of the earth which has gone on throughout the whole history and is still going on.? (2) It was not until 1910, that an American Geologist named F.B.Taylor, proposed the idea of a continental drift. His scientific peers dismissed Taylor's idea, because there was just not enough proof. However, Taylor's idea was then resurfaced by a German scientist named Alfred Wegener. He proposed that the continents surrounding the Atlantic Ocean, Africa and South America fit together like a jigsaw puzzle. Wegener was a balloonist, astronomer, explorer, meteorologist, while in his spare time he researched paleontology, geophysics and geology. His broad range of studies enabled him to incorporate his theory of Plate Tectonics. Wegener, later in 1915 while in sick leave from the German military published his idea that interpreted how his continental drift theory worked. He proposed that a huge landamass called Pangea, meaning (all land?) existed 200 million years ago. He furthered explained that this super continent began to drift apart very slowly throughout millions of years into what it looks like now. Wegener went on several expeditions through out his life to the continents of South America and Africa. He came back with evidence to support his claim of plate tectonics. Wegener and his expedition brought back rock structures, fossils, and evidence of ancient climates. When it came to rock structures, Wegener looked for the similarities of the rocks found along coastlines and the mountain belts found on the continents. They looked at the mountain belts of the Appalachian Mountains and the Caledonian Mountains in Scandinavia and the British Isles. These two continuos belts contained similar rock structures and the ages of these rocks matched the on both ends of the African and South American continents. Wegener also found evidence of massive climatic changes. He researched and found out that ancient glacial deposits were found indicating that ice sheets covered a large part of the Southern Hemisphere, India and Australia. Wegener's explanation of the glaciation was that the ?landmasses where all fitted together as a super continent with South Africa centered over the South Pole.? (1.) Pag. 474) He furthered explained that the Northern Hemisphere was near the equator supporting the idea of coal deposits being located there. Wegener was more intrigued of the fact that fossilized remains were being found along South America and Africa. Remains of the aquatic prehistoric dinosaur called Mesosaurus were only found in eastern South America and Africa. Plant remains were also being found. For example the fossil fern Glossopteris were found sparingly throughout Africa, Australia, India, and South America. Furthermore, this plant was found in polar climates, supporting his theory of connected landmasses. Organisms like the Australian Marsupials and the marsupial opossums found in the Americas, which have a definite fossil link also supports Wegener's theory. Alfred Wegener's theories were not immediately accepted by the scientific community. One of his faults was that he could not prove how the continents moved across the globe. Wegener's suggestion was that ?tidal influence from the moon?(1. Pag. 475) was to be credited. However the science community proved him wrong. Eventhough he was in the right direction, he could not completely and precisely determine how the continental drift was accomplished. Therefore, his theories were dropped as rubbish. Essentially, Wegener was ahead of his time. It was not until years later that other scientist cleaned up some of Wegener's mistakes and resurfaced the Plate Tectonics theory. Thanks to the study of magnetism a whole