...The Development Theory of Plate Tectonics * Introduction In this report I will be describing the theory of the Plate tectonics and showing its main points of development. There are matches between the shapes of South America and Africa. The two continents look like pieces of a jigsaw. Alfred Wegner thought that this meant that the continents where moving. They had once been joined together. He looked for evidence which was recorded in their rocks. In 1912 Wegner presented the idea of continental drift and his supporting evidence to a meeting of the Geological Society of Frankfurt. Geologists around the world read the English Translation of his book the Origin of Continents and Oceans which was published in 1922. He found interesting evidence from mountain chains, rocks and fossils on different continents. However most geologists reject such a grand and unlikely explanation of these explanations. Wegner Claimed: Fossil plants from both Africa and South America were identical. Reptile fossils matched too. People claimed he couldn’t just draw conclusions from a few fossils. They thought that there could once have been a land bridge joining Africa and South America. Wegner disagreed with the idea and asked for the evidence of there being a land bridge. The rock types on each continent fit like pictures on a jigsaw. The continents were once joined together. He claimed continents moved slowly. However one of the key principles of geology was to ‘use the present to interpret...
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...According to the plate tectonic theory, the earths crust is made up of 8 main plates, as well as a number of smaller ones. These plates float on top of the asthenosphere and move around quite regularly. This movement causes interaction between the plates which is thought to bring about seismic and volcanic events at its margins. Therefore the plate tectonics theory is a key concept in understanding the distribution of seismic and volcanic events. Plate tectonic theory was first suggested by Alfred Wegener in 1912. He believed that a single continent called Pangea existed around 300 million years ago before splitting it began to split because of continental drift, into two continents and continuing to split to form the continents we see today. His theory was supported by both geological and biological evidence, such as the bulge of South America seeming to fit into the indent of West Africa. He believed this suggested that they were once attached and had been separated through continental drift. Later evidence was also found as fossil remains of the reptile mesosaurus were found in both South America and Southern Africa. It is unlikely that the same reptile could have developed in both area or that it could have migrated across the Atlantic especially due to the fact that the reptile was believed to be a poor swimmer. This continental drift leads to seismic and volcanic events and is very important in understanding their distribution. Although Wegeners ideas seemed simple...
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...Evolution and Theory of Plate Tectonics The most important and vital development of plate tectonic theory and evolution appeared to be among the most crucial scientific achievements in the 20th century. The theory concept offers a relevant structure towards the knowledge of all natural Earth attributes. It additionally provides one particular framework with regard to the knowledge of both planet's origin and outlook. Notably, the evolution of life on the planet remains significantly impacted by plate tectonic processes. This may involve the historic, societal, and cultural advancement of humanity. In other words, plate tectonic theory is an encompassing conjecture regarding different scientific theories that demonstrate the naturally occurring Earth characteristics have actually formed the historical past from the solid Earth, the oceans, the atmosphere, and all life organisms. Many scientific theories are so well established that no new evidence is likely to alter them substantially. For example, no new evidence will demonstrate that the Earth does not orbit around the sun (heliocentric theory), or that living things are not made of cells (cell theory), that matter is not composed of atoms, or that the surface of the Earth is not divided into solid plates that have moved over geological timescales (the theory of plate tectonics). Like these other foundational scientific theories, the theory of evolution is supported by so many observations and confirming experiments...
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...towards proving that plate tectonics theory is valid” Discuss the extent to which you agree with this statement. (40 Marks) The theory of plate tectonics is a relatively new idea – only conceived and developed within the last 100 years and is now generally accepted as the explanation for the causation of earthquakes and volcanoes and where they occur. It has now replaced the theory that tectonic events are caused by god in most western countries. The theory of plate tectonics was first developed by Alfred Wegener in 1912. He saw that the continents seem to have a jig-saw fit e.g. Africa and South America coastlines fitting together, suggesting that they were at one time joined together as part of a super continent called Gondwanaland and the other super continent Laurasia was in the north. Later evidence supported this – the fossilised remains of a dinosaur, the mosasaurs, was found on the coasts of Brazil and Gabon. There were also the same fossilised pollen species and rock sediments on these coastlines. Wegener’s ideas, though simple, were proved further right and built upon which further increased our understanding of tectonic events. Sea floor spreading was discovered showing that rock is being created and destroyed, leading us to believe in the existence of plates and plate boundaries. Sea floor spreading was shown in the Atlantic, where it is believed the Eurasian and North American plates are moving apart, at what is called a constructive plate boundary. Here magma...
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...University of Phoenix Material Effects of the Motions of Tectonic Plates Worksheet From Visualizing Earth Science, by Merali, Z., and Skinner, B. J, 2009, Hoboken, NJ: Wiley. Copyright 2009 by Wiley. Adapted with permission. Part 1 This diagram was similar to one Alfred Wegener drew to show the distribution of continents 300 million years ago. His theory of continental drift was met with skepticism in the scientific community. [pic] 1. Describe three forms of evidence Wegener used to support his ideas of continental drift. Wegner suggested that the continental shelves of the continents seemed to fit together similar to a puzzle. According Bugielski (1999), "continents in the southern hemisphere exhibit an identical pattern of rock and fossils known as the Gondwana sequence. The most logical explanation was that the continents themselves were once parts of a much larger super-continent (Early development of plate tectonics). Another point that Wegener used as evidence was by looking at the glacial till deposits. When the contintents were together, the glacial movement was, "more streamlined motion of the glacier from southern Africa and Northern Australia outward" (Bugielski, 1999). The last important piece of evidence that was used was by examinung sedimentary rock that was able to show a change in climates proving the theory of the continental drift or that the poles had moved. (Bugielski, 1999). Bugielski, M. (1999). The Richard Stockton...
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...Structure and composition of the Earth The overall composition of the Earth is very similar to that of meteorites, and because of this, it is thought that the Earth originally formed from Planetesimals composed largely of metallic iron and silicates. What makes Earth unique? Soon after the Earth formed, unique processes occurred - division into metallic core, silicate mantle and crust - which, along with surface water, made it different from the other planets in our Solar System. The formation of the early mantle was important as it consisted primarily of ferromagnesium silicate minerals, some of which contained water as an essential component (e.g. amphibole group minerals). Water-bearing magmas (molten rock) from deep in the lower mantle then rose towards the surface (being liquid, they were lighter than the surrounding solid rock) and emerged as volcanic eruptions. The Earth's atmosphere and hydrosphere developed from the degassing (loss of gaseous elements such as carbon, hydrogen and oxygen) of the early-formed core and mantle during this volcanic activity. In the present, abundant gases are still released from the Earth during volcanic eruptions and these are mainly composed of water (77%), carbon dioxide (12%), sulfur dioxide (7%), and nitrogen (3%), with minor amounts of hydrogen, carbon monoxide, sulfur, chlorine and argon. The Earth can be divided into two main parts. Atmosphere: measured from the surface of the Earth upwards to 150 km (anything above this...
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...1. The continental drift theory first supported by Alfred Wegener, is the theory that 220 million years ago the continents known today were once a supercontinent known as Pangaea. Over time, the continents drifted apart along the Earth’s surface to their current locations due to the rotation of the Earth. To support this theory, Wegener collected rocks and fossils from opposite sides of the Atlantic Ocean as proof that the continents were once united (Abbott, 2012). Sea floor spreading and magnetization patterns on sea floors also support the theory of continental drift. The floor of the Atlantic Ocean is striped with parallel bands of magnetized rock. These bands are symmetrical and parallel with the mid Atlantic ridge (Abbott, 2012). Each stripe has a twin on the opposite side of the ridge. These magnetized stripes moving away from the ridge support the theory of sea floor spreading. Plate tectonics is the description of the movements of plates and the effects of plate formation, collision, subduction, and slide-past (Abbott 2012). Plates are broken pieces of the Earth’s lithosphere. Plate tectonic theory states that the Earth’s crust is located on top of the lithosphere, allowing the crust to move. The crust moves due to forces generated within the asthenosphere, fueled by the internal heat of the Earth’s core. Four major scientific developments spurred the formulation of the plate-tectonics theory: (1) demonstration of the ruggedness and youth of the ocean floor; (2) confirmation...
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...Plate tectonics (from the Late Latin tectonicus, from the Greek: τεκτονικός "pertaining to building")[1] is a scientific theory that describes the large-scale motion of Earth's lithosphere. This theoretical model builds on the concept of continental drift which was developed during the first few decades of the 20th century. The geoscientific community accepted the theory after the concepts of seafloor spreading were later developed in the late 1950s and early 1960s. The lithosphere, which is the rigid outermost shell of a planet (on Earth, the crust and upper mantle), is broken up into tectonic plates. On Earth, there are seven or eight major plates (depending on how they are defined) and many minor plates. Where plates meet, their relative motion determines the type of boundary; convergent, divergent, or transform. Earthquakes, volcanic activity, mountain-building, and oceanic trench formation occur along these plate boundaries. The lateral relative movement of the plates typically varies from zero to 100 mm annually.[2] Tectonic plates are composed of oceanic lithosphere and thicker continental lithosphere, each topped by its own kind of crust. Along convergent boundaries, subduction carries plates into the mantle; the material lost is roughly balanced by the formation of new (oceanic) crust along divergent margins by seafloor spreading. In this way, the total surface of the globe remains the same. This prediction of plate tectonics is also referred to as the conveyor...
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...Physical Geography Structured Questions o 1 from Section B – Human Geography Structured Questions o 1 from Section C – Essay Questions (You must not answer the option answered in either Section A or Section B) [pic] |Plate tectonics and associated hazards |Ecosystems: Change and Challenge | | | | |Plate movement |Nature of ecosystems | |Earth structure, plate tectonics theory: convection |Structure of ecosystems, energy flows, trophic levels, | |currents and sea-floor spreading. Evidence: |food chains and food webs. | |continental drift and palaeomagnetism. | | |Destructive, constructive and conservative plate |Ecosystems in the British Isles over time | |margins. Processes: seismicity and vulcanicity. |Succession and climatic climax: illustrated...
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...Chapter 2: Plate Tectonics and Physical Hazards Earth Structure - Inner Core - Solid, High Temperature, 90% Iron, 1300 km thick - Outer Core - Liquid, similar to inner core, 2000 km thick, density of 10.7 g/cm3 - Mantle - Solid, iron & magnesium-rich silicate rocks, 3000 km thick, density of 4.5 g/cm3 -Lithosphere - Outer rind of the Earth - made up of tectonic plates - Asthenosphere - Below lithosphere - Hot layer of weak rocks - Crust - Outer rock layer of Earth, density of 2.8 g/cm3 - Moho – the boundary between Earth’s crust and mantle, marks the base of the continental crust, separates lighter crustal rocks from the more dense mantle - Isostacy (buoyancy) is the reason why there’s a difference in elevation between continental and oceanic crusts - Plate tectonics describes the movements of Earth’s plate (moves up to 11 cm/year) Hazards and Plate Boundaries - Most of tectonic actions, like earthquakes and volcanoes, occur near boundaries of the plates - Divergent boundaries: plates pulled away from each other by the sinking of lithosphere at oceanic trenches - If the plates are continental plates, once pulled apart they will form a continental rift zone, which can develop into a new ocean. Spreading continues allowing basaltic magma to push to the surface. - Convergent boundaries: plates moving towards each other - Subduction zone: when one or both plates are oceanic and the denser ones slides down into the asthenosphere...
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...Physical Geography Structured Questions o 1 from Section B – Human Geography Structured Questions o 1 from Section C – Essay Questions (You must not answer the option answered in either Section A or Section B) [pic] |Plate tectonics and associated hazards |Ecosystems: Change and Challenge | | | | |Plate movement |Nature of ecosystems | |Earth structure, plate tectonics theory: convection |Structure of ecosystems, energy flows, trophic levels, | |currents and sea-floor spreading. Evidence: |food chains and food webs. | |continental drift and palaeomagnetism. | | |Destructive, constructive and conservative plate |Ecosystems in the British Isles over time | |margins. Processes: seismicity and vulcanicity. |Succession and climatic climax: illustrated...
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...[pic] Axia College Course Design Guide SCI/245 Version 5 Physical Geology Start Date: 9/24/2012 End Date: 11/25/2012 Course Materials Murck, B. W., Skinner, B. J., & Mackenzie, D. (2008). Visualizing geology. Hoboken, NJ: John Wiley & Sons. Axia College’s Writing Style Handbook, available online at https://axiaecampus.phoenix.edu/Writing_Style_Handbook_AxiaUOP.pdf All electronic materials are available on your student Web site. Please print a copy of this syllabus for handy reference. Whenever there is a question about what assignments are due, please remember this syllabus is considered the ruling document. Copyright Copyright © 2009, 2008, 2007 by University of Phoenix. All rights reserved. University of Phoenix® is a registered trademark of Apollo Group, Inc. in the United States and/or other countries. Microsoft®, Windows®, and Windows NT® are registered trademarks of Microsoft Corporation in the United States and/or other countries. All other company and product names are trademarks or registered trademarks of their respective companies. Use of these marks is not intended to imply endorsement, sponsorship, or affiliation. Edited in accordance with University of Phoenix® editorial standards and practices. Facilitator...
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...Exam series | Sect A Plate Tec(7 marks) | Sect APlate tec(8 marks) | Sect A Plate tec(10 marks) | | Sect CPlate tec essay (40 marks) | June 2010 | Study fig 1 a photo …recent earthquake. Using fig 1 only, comment on the evidence that suggest that an earthquake has recently taken place | Describe how seismic waves and earthquakes can be measured | With reference to two seismic events you have studied from contrasting areas of the world, compare the ways in which earthquakes and their impacts have been managed | | “The hazards presented by volcanic and seismic events have the greatest impact on the world’s poorest people” To what extent do you agree with this view? | Jan 2011 | Study fig 1, a map showing tectonic features in the Philippines. Comment on the degree to which the area of the Philippines might be subject to tectonic hazards | Outline the formation of hot spots and explain their relationship to plate movement | With reference to 2 volcanic events that you have studied from contrasting areas of the world, compare the nature of the volcanic hazard and its impact | | “Volcanic and seismic events are major pieces of evidence towards proving that plate tectonics theory is valid”. Discuss the extent to which you agree with this statement. | June 2011 | Study fig 1 which is an image of the sea bed of the N Atlantic Ocean … Comment on the extent to which the features shown support the theory of plate tectonics. | Describe the characteristics of, and explain the formation...
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...Earthquakes and Other Tectonic Disturbances Pose One of the Major Physical Threats to Civilisations Particularly in Developing Countries The major factors to this will be looking at tectonic activity, the earthquakes they cause aswell as the distribution of these developing civilisations in order to ascertain whether the major threat to their final goal of civilisation is plausible or not. Earthquakes are defined in the Oxford dictionary as: a sudden release of energy in the earth's crust or upper mantle; usually caused by movement along a fault plane or by volcanic activity and resulting in the generation of seismic waves which can be destructive. Tectonic plates are defined as: A theory explaining the structure of the earth’s crust and many associated phenomena as resulting from the interaction of rigid lithospheric plates which move slowly over the underlying mantle; by the same dictionary. Finally, civilisations are defined as: The process by which a society or place reaches an advanced stage of social development and organization. The largest cities tend to be in developing countries due to the fact they have not yet reached stage 5 of the Demographic Transition Model and many of the pull factors that cause cities to grow still exist. MEDC’s tend to have reached a point whereby people move out of major cities in order to find a suitable environment for family life. Thus from this we can see that already LEDC’s are most at risk from tectonic activity. Earthquakes do...
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...Describe the type of tectonic and seismic activity which occurs at each plate boundary (25 mark) In the theory of plate tectonics, the earth's crust is broken into plates that move around relative to each other. As a result of this movement, three types of plate boundaries are formed: Divergent, Convergent- Oceanic/Continental & Continental/Continental, and Transform boundaries. Not all plate boundaries fit into the main groups shown above. In some parts of the world the boundaries are not easily defined because the deformation caused by the plates covers a wide area rather than having clearly defined plate edges. This deformation is called a plate-boundary zone. The smaller fragments of plates are called microplates. The destruction of the earth’s crust occurs along plate boundaries, where plates are moving towards each other and the creation of the crust occurs where plates are moving away from each other. A divergent plate boundary, also knows as an constructive or extensional boundary) is a tectonic boundary where two plates are moving away from one another forming new crust as magma rises from the earth’s surface between the two plates. The boundaries are found along spreading centres -The Mid-Atlantic ridge being an example of a ‘textbook’ slow spreading centre and in contrast the East Pacific Rise is an example of a fast spreading ridge. Divergent boundaries can be Continental or Oceanic. When a divergent boundary occurs underneath ocean lithosphere, the rising...
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