Plate Tectonics

Section: Marketing Essays

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 new window of scientific evaluations emerged to support the theory of Plate Tectonics. S.K. Runcorn proposed an interesting idea. It was found that "the magnetic alignments in the iron-rich minerals in lava flow of different ages was found to vary widely."(1. Pag. 478) This was strong evidence that the magnetic poles of the earth had migrated through time, meaning that lava flows had moved and so did the continents. This event is called polar wandering. For a long period of time there was still a lot of questions that needed to be answered about the Plate Tectonics theory. Thanks to technological efforts and the mapping of the ocean floor, it became known that there was an oceanic ridge system.

Ocean Ridges are slices in ocean floor that extended for 70,000 kilometers. It was not until 1960, when a professor from Princeton University, Harry Hess, suggested Sea Floor spreading. His idea stated that new sea floor was being spread through mid-ocean ridges. As scientist clashed ideas they suggested that continental drift and ocean floor spreading were incorporated in the theory of plate tectonics. They implied that the outer layer of earth called the lithosphere overlaid another layer of earth called the aesthenospshere. It was later learned that the lithosphere was broken into seven large and small plates. Research concluded that these plates are in motion and have been changing shape through billions of years. However, scientists were clear to verify that these plates only moved one to two centimeters a year. Over millions of years these centimeter accumulated from the big landmass of Pangea to what the continents look like now. In order to understand the movement of these plates one has to look at the how and where these plates move. Divergent boundaries are known as plates that move away from their ridge axis. This is due to the hot molten rock submerging from the mantel into the ocean floor, creating new oceanic crust, also known as seafloor spreading. Some of these divergent zones can be found in the Mid-Atlantic Ridge, Red Sea, and the Gulf of Mexico, where it separates the Baja Peninsula from Mexico. Convergent Boundaries take place where the oceanic plates descend into the asthenospshere. This region of activity is called subduction zone. As the plate bends it creates a deep-ocean trench.

Words: 556