...Plate Tectonics Damian Neal EG 481 May 14, 2012 Instructor: Dr. M. Jiru Plate Tectonics Outline I. Revolution in Earth Science Continental Drift Hypothesis Sea-Floor Spreading: Clues and Processes II. The Plate Tectonic Model Motivating Observations Types of Plate Margins (Divergent and Convergent Margins) III. The Search for a Mechanism The Tectonic Cycle (the motion and influences that occur during the cycle) Plate Tectonics The location where two plates meet is called a plate boundary, and plate boundaries are commonly associated with geological events such as earthquakes and the creation of topographic features such as mountains, volcanoes, mid-ocean ridges, and oceanic trenches. The majority of the world's active volcanoes occur along plate boundaries. In 1912 Alfred Wegener introduced his continental drift hypothesis. Wegener's believed that at once the continents were at one time were all connected together forming a single continent in which, he referred to as the supercontinent. The supercontinent may also be referred to as the Pangaea, defined as the all lands. Wegener believed that the supercontinent had split into fragments like pieces of ice floating on a pond and that the fragments had slowly drifted to their present locations (Merali & Skinner, 2009). However, there was a problem with Wegener’s hypothesis...
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...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. Wegener used landorms, climate, and fossils to support his theory of continental drift. He said that when it came to landforms all the continents seemed to fit like a “jigsaw puzzle”. Even went as as far to say the mountain ranges seemed to line up as well. Wegener said that the same fossils and rock from one continent would end up on a different continent. For instance a fossil found in Africa would also be found in South America. When it came to climate, Wegener said that some fossils did not match the climate. For instance, there a glacier scratches in South Africa. 2. Years later, the continental drift theory reemerged as plate tectonic theory, with two additional pieces of evidence. [pic] [pic] Refer to the images above. Discuss in detail the two pieces of additional evidence that supported Wegener’s theory, now known as the theory of plate tectonics. The first image...
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...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. 1. Describe three forms of evidence Wegener used to support his ideas of continental drift. 2. • Continental Margins (Visually land masses fit together like a puzzle) 3. • Rock layers (similarity on the coast lines as well in a different continent 4. • Fossil evidence (How some animals were identical on the other side of the world, and how tropical plants were found in Arctic regions. 5. Years later, the continental drift theory reemerged as plate tectonic theory, with two additional pieces of evidence. Refer to the images above. Discuss in detail the two pieces of additional evidence that supported Wegener’s theory, now known as the theory of plate tectonics. Part 2 Write paragraph answers to the following questions using what you have learned from Visualizing Earth Science and the assigned WileyPlus® GeoDiscoveries®. 1. How does the motion of the tectonic plates affect the climate? 2. How does the motion of the tectonic plates affect the geography? 3. How does the motion of the tectonic plates affect the distribution...
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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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...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. 1. Describe three forms of evidence Wegener used to support his ideas of continental drift. • Continental Margins (Visually land masses fit together like a puzzle) • Rock layers (similarity on the coast lines as well in a different continent • Fossil evidence (How some animals were identical on the other side of the world, and how tropical plants were found in Arctic regions. 2. Years later, the continental drift theory reemerged as plate tectonic theory, with two additional pieces of evidence. Refer to the images above. Discuss in detail the two pieces of additional evidence that supported Wegener’s theory, now known as the theory of plate tectonics. • One additional piece of evidence was the mapping of the ocean sea floor. When all these investigations about the ocean sea floor were given to scientist, a new light in the composition of the rocks and their distribution was discovered. Wegener's ideas started now to make sense for most geologists, the saddest part is that at this time Wegener was already dead so he could...
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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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...Plate Tectonics Theory Gaining Credence The theory of Plate Tectonics is a surprisingly recent discovery. The first driving force was in 1915 when Alfred Wegener published his book The Origin of Continents and Oceans. Wegener proposed the idea that the earth’s continent had once been a single super-continent, which he named Pangaea. Wegener explained how many things on earth were interconnected and Pangaea could be the solution for many scientific queries at the time. Many colleagues in the geologic field were skeptical of Wegener’s proposal because he couldn’t explain why the plates moved. It wasn’t until the 1960’s when enough data was collected on projects such as Bathymetry and the Phenomenon of Polar Wander, that a majority of scientists accepted Plate Tectonics. The theory of Plate Tectonics is best described in layers. On top we have the least dense particles such as nitrogen and oxygen gas that make up our atmosphere. As we look deeper into the earth, data shows that denser elements and molecules are pulled into the center and less dense objects ejected due to mass. The core of our earth is made mostly of nickel and iron. The plates that move on the earth’s surface are dominantly solid objects that consist of our earth’s crust and the upper mantle. This is called the lithosphere. The upper part of the lithosphere, the crust, can be separated into two types, continental and oceanic. Continental crust is much thicker than the oceanic crust. This means the lithosphere...
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...underneath the surface humans walk on every day. Those rocks are called tectonic plates, and about fifty years ago, scientists came to the conclusion that they move. Tectonic plates affect the Earth’s landscape drastically. Plates can change the Earth’s landscape by creating geographical features, causing natural phenomena such as earthquakes, and causing the drifting continents. Tectonic plates are located in between the upper mantle and crust, which are layers of the Earth. “The motion of tectonic plates is the biggest force reshaping Earth’s surface” (Land, 12). Since the plates are the biggest force, the assumption that...
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...“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. Plate tectonics is the theory that suggests that the Lithosphere is separated up into approximately twelve plates that can be moved around via convection currents, changing the land and sea formations across the globe. Since interest began during the early 20th century a variety of propositions have been put forward to suggest the existence of plate tectonics. The most prominent of these theories is the existence of seismic waves and volcanic activity, especially the location and distribution of these. Along with these theories is the discovery of fossils and their locations across the globe, as well as the shape of the existing continents and the “jigsaw” theory. During the 17th century Francis Bacon noted that the West coast of Africa and Europe coincidentally looked as though they would fit with the East coast of the Americas. However, Bacon had little evidence for this theory, meaning it was swiftly forgotten. During the 1920’s, Alfred Wegner, proposed that the formation of the continents today has occurred via continental drift. However, Wegner goes on to suggest that 300 million years ago there was a single landmass, commonly known as Pangaea, as shown in Figure 1.1. Pangaea was one supercontinent that existed during the late Palaeozoic and carrying on into the early Mesozoic eras. It consisted of...
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...earthquakes(3) of the (eastern) mediterranean area Table of content Introduction 1 Geodynamics 2 Volcanism and Earthquakes 4 Paleoenvironment 6 References: 8 Introduction The Mediterranean Sea has been one of the most profound areas for geologists to study at. Amongst each other they also refer to the sea as ‘Mare Nostrum’ which is Latin for ‘our sea’. It is an area where many different types of tectonic plates come together, moving in different directions. It also has the perfect latitude to make it a sensitive area regarding astronomically induced oscillations. In the past it has been a fascinating area for geological research and further analysis of the area would contribute greatly of many geological process in an accurate time-frame. This report will first explain the geodynamics of the area focussing on the subduction processes in the eastern Mediterranean and how extension is possible in an overall compressive state. Secondly the volcanic activity and earthquake activity in the Aegean domain will be addressed, looking at how they are related to tectonic plate configuration and finally discuss the Messinian Salinity Crisis which as part of a dramatic change in paleoenvironmental conditions. Geodynamics Geodynamics is a subfield of the earth sciences that looks into movements and processes of the earth’s mantle. Some of the predominant topics...
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...September 18, 2011 There are four types of tectonic plate margins, the meeting place of one plate with another. The four plates are destructive, constructive, collision, and conservative. Plates are constantly moving or changing position. The divergent boundaries are where new crust is generated as the plates pull away from each other. The convergent boundaries are where the crust is destroyed as one plate drives under another. The Transform boundaries are where the crust is neither produced nor destroyed as the plates slide horizontally past each other. And the Plate boundary zones are the broad belts in which boundaries are not well defined and the effects of plate interaction are unclear. They move slower than a few centimeters a year, slower than fingernails grow. The plates move in three ways, they move together, converge, they move apart, diverge, or they move past each other. They are said to have three types of edges or boundaries, convergent, divergent, and transform. Convergence is hen the leading edge of a plate meets another, one turns downward. The downward motion is called subduction, subducted plates move down into and through the asthenosphere and gradually disappears. Plates diverge at volcanic zones in ocean basins, the mid-ocean ridges. These are long, huge cracks where lava rises from below and freezes into new lithosphere. The two sides of the crack are continually pulled apart, and the plates gain new material. The north Atlantic island...
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...as to why these events happen. In addition, I will also talk about the new inquiries concerning earthquakes and what leads up to these questions that may still be unanswered. II. General Overview To understand how earthquakes form, what causes them, and the components that make it up, one must know exactly what an earthquake is. Webster’s Dictionary states that an earthquake is the “shaking or trembling of the earth that is volcanic or tectonic in origin.” While this describes the movement and the cause, it doesn’t describe why. Earthquakes happen when the underground rock immediately burst against the fault. This activity causes seismic waves that travel along the earth’s crust to vibrate. When this occurs, it is because the plates are being stretched or squeezed and the movement of the magma is building up pressure. After intense pressure, eventually it will move outside of the crust and continue in a motion outward an upward. The cause of earthquakes falls into two categories. The first is the tectonic plate. In this category, the crust and upper mantle...
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...located offshore, the seabed sometimes suffers sufficient displacement to cause a tsunami. The shaking in earthquakes can also trigger landslides and occasionally volcanic activity. In its most generic sense, the word earthquake is used to describe any seismic event — whether a natural phenomenon or an event caused by humans — that generates seismic waves. Earthquakes are caused mostly by rupture of geological faults, but also by volcanic activity, landslides, mine blasts, and nuclear experiments. An earthquake's point of initial rupture is called its focus orhypocenter. The term epicenter refers to the point at ground level directly above the hypocenter. [pic] [pic] Global earthquake epicenters, 1963–1998 [pic] [pic] Global plate tectonic movement |Contents | | [hide] | |1 Naturally occurring earthquakes | |1.1...
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...on the Mississippi River and interstate 55. It has a population of 3154 residents, and it is considered as a small community in United States. New Madrid, MO is located at 36.59° North latitude, 89.53° West longitude and about 89 meters altitude above the sea level. Geographic coordinates: Latitude: 36.59° North Longitude: 89.53° West Altitude: 89 m [pic] 3. General geologic setting: A state’s general geologic setting basically includes what types of rock has build up the overall region, what structural features that state has, like, mountains and faults. It also includes plate tectonic setting and also an overall geologic map. 3.1. Geologic map: [pic] 3.2. Plate tectonic setting: The middle of the North American tectonic plate actually contains the new Madrid fault zone. One of the attribute of this plate is, this plate is thinner and weaker near to its center. As a result, it formed a rift zone....
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...Earthquakes If one could have stood out in space for a fantastically long time and looked back at the Earth, one would have seen the continents themselves in motion, drifting apart on their crustal plates, held afloat by the fire beneath. That is a poetically turned phrase from Lewis Thomas, which beautifully sums up the mechanics behind plate tectonics, and ultimately behind earthquakes. The following is a brief sketch on earthquakes, their cause and effect, how they are measured, and an area where they frequently occur. Plate Margins There are two different plate margins. These are convergent margins and divergent margins. When two plates move and finally come together it is called convergent margins. Divergent margins are the exact opposite than convergent margins. Instead of moving towards each other the plates move away from each other. Measuring Earthquakes Just by looking at the mass destruction left behind by earthquakes one can see that they vary in size and strength. Earthquakes are measured in size and strength by what is called the Richter scale. The Richter scale was developed by a man names Charles Richter. The majorities of the earthquakes that occur each year are a magnitude of 2.5 or less and go unnoticed by humans. The Richter scale can measure both small and very large earthquakes; this could be ripples in the earth that not one person could feel or it could be earthquakes of mass destruction just like the earthquake of Japan. Also the movement magnitude...
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