In 1912, Alfred Wegener, a German scientist, was the first to notice this and develop the theory of plate tectonics. He noticed that the earth’s continents fit together almost like a jigsaw puzzle. This, combined with the fact that similar fossils and rock types are found on different continents separated by large bodies of water, helped him formulate his conjecture. He contended that the plates at one point formed one large continent called Pangea, which allowed like fossils and rock types to become closer together, which broke apart. Despite how well the continents fit together and the facts about the geology, the general public would not accept Wagener’s proposal. This is largely due to religious conflicts and the lack of evidence presented to them.
The earth’s surface and the mantle make up the composition of the tectonic plates. This layer, called the lithosphere, rests on top of the asthenosphere, a layer of molten rock. The asthenosphere is constantly moving and flowing due to the extreme pressures and temperatures. When the mantle heats the asthenosphere the heat rises causing the material at the top to spread apart. The tectonic plates floating on the molten rock move away from each other. As the matter eventually cools it becomes less dense, causing the lithosphere to descend with it. This process is called subduction.
If this occurs between a continental plate and an oceanic plate, the plate tectonic Theory">oceanic plate sinks into the asthenosphere and melts, producing magma. This magma rises to the top occasionally and erupts causing a volcano to form. As a result of this most volcanoes lie along the edge of oceanic and continental plates. The ring of fire bordering along the Pacific Ocean plate is an example of this. The tectonic plates are constantly in motion and as a result come in contact with each other. Plates interact with each other in three ways each forming a different type of boundary.
The Term Paper on Sedimentary Rock 2
Sedimentary rock formation begins with igneous, metamorphic, or other sedimentary rocks. When these rocks are exposed at the earth’s surface they begin the long slow but relentless process of becoming sedimentary rock. Weathering All rocks are subject to weathering. Weathering is anything that breaks the rocks into smaller pieces or sediments. This can happen by the forces of like wind, rain, and ...
The three boundaries include divergent, convergent, and conservative boundaries. Divergent and convergent boundaries are the two main types of movement and were described earlier. Divergent boundaries occur when two plates move away from each other creating plate matter in their wake. This causes a gap between the plates that is indicated by a rise or a ridge. This is also referred to as sea floor spreading. The reason of this is most of this type of action occurs in the center of the world’s major ocean basins.
Convergent margins form when two plates collide with one another. One of the two plates slides below the other at about half of a ninety-degree angle resulting in a loss of plate matter. When one plate is an oceanic mass and the other is a continental mass the oceanic plate moves beneath the other. This subduction produces a deep ocean trench and the edge of the lower plate can be determined by the examination of deep earthquakes. This collision quite often results in volcanoes, which occur at the edge of the upper plate, marking the plate distinctly. The last type of boundary is the conservative or transform margin.
When two plates slide past each other plate mass is neither created nor demolished. This boundary is often marked by a large fault, the most famous being the San Andreas Fault System. The world’s surface is covered mostly by oceanic crust that is continually recycled. It is believed that the plate are constantly replacing themselves through subduction and that most of the crust is not more than 200 million years old. At this time there are seven major continental and oceanic plates and several smaller ones. The larger plates include the Pacific, North and South American, Eurasian, Antarctic, African, and Indian plates. Some of the smaller plates include the Cocos, Nazca, Caribbean, and Gorda plates. In conclusion, the plate tectonic theory involves the movement of plates and their composition.
The Term Paper on Volcanic and Seismic Events as Proof of Plate Tectonic Theory
... destructive plate boundaries which account for creating 80% of the world’s active volcanoes. The melting crust at Subduction Zones (oceanic-oceanic or continental-oceanic) ... currents also help drag the plates apart and then pull them down at convergent boundaries. This can be seen at ... it was long thought to be a cooling solid mass. Geologists later discovered that radioactive decay provided a heat ...
The theory is important to understand the world’s geography and history. Further research can lead to preventive measures for natural disasters such as volcanoes and earthquakes, direct byproducts of tectonic activity. This could save numbers of lives and vast amounts of money in repairing the damage..
