...The Creation Of The Floor Karina Decubas SCI/209 Nov 2,2015 Shannon Shoemaker The Creation Of The Ocean Floor Oceanography is the branch of science that studies the ocean and vast amount of topics. I learned the importance of this branch among science. Science has answered many questions and created many theories that goes beyond this science in specific but help to answer more question in other branch of science. Two very important theories are the Continental Drift and the plate tectonics. These theories try to solve the question about the actual position of the continents and how they got there. There are so many terms and information to learn in order to understand these two theories for example plate boundaries, Fault, oceanic floor, volcanoes and more. Plate Boundaries A Plate Boundaries is the location where two plates meet. There are three different plate boundaries. The Divergent plate boundaries are where new crust is generated as the plates pull away from each other. The Divergent plate boundaries occurs along spreading centers where plates are moving apart and the new crust is created by magma pushing up from mantle. A good example is the Mid-Atlantic ridge. The rate of spreading along the Mid-Atlantic ridge averages 2.5 centimeters per year. Convergent Boundaries is where the crust is destroyed as one plate dives under another. The Size of the earth has not change significantly during the past 600 millions years. The...
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...plate tectonics, and sea-floor spreading explain what the earth used to look like and why it looks like it does today. Continental drift states that all the continents used to all be one supercontinent called Pangaea, and over the last 200 million years, the continents slowly drifted apart to where they are now (Evers 1). The theory of tectonic plates states that all the continents and oceans sit on plates or large pieces of rock under the earth and slowly move by convection currents in the mantle (Cowan 1). Sea-floor spreading is the process in which magma from a ridge cools and creates ocean floor. This new ocean floor pushes the older floor towards trenches....
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...drift, sea-floor spreading, and plate tectonics have many similarities and differences. Continental drift is the theory that explains how the continents shift on Earth’s surface. Sea-floor spreading is the process where new sea-floor is created as molten material which rises in the from the Earth’s mantle. Plate tectonics is the theory at which the lithosphere is separated into different plates, and are moving along the asthenosphere. Continental drift, sea-floor spreading and plate tectonics all have similarities and differences. All three of these pieces are theories, which all incorporate or are supported by plate tectonics. Continental drift, sea-floor spreading and plate tectonics have different creators. Continental drift, sea-floor spreading and plate tectonics are similar in many ways. One way that continental drift and plate tectonics similar is that they both deal with the movement of continents. Continental drift explains how the continents shift on Earth’s surface and how the continents are...
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...‘plastic’ semi-solid rock in the lower mantle. Continental drift: the separating of continents by drifting across the oceans. Magnetic striping: patterns of magnetism trapped in rocks on each side of plate boundaries. Ocean trench: a deep trench in the ocean floor that is much deeper than the rest of the ocean floor. Plate tectonics: the theory that the Earth’s crust is cracked into many large pieces that move on the asthenosphere. Rifting: the process of continents breaking up, subsiding and allowing in the sea. Seafloor spreading: the process of new crust forming at the ocean ridges and spreading outwards. Subduction: where the crust is sinking down into the Earth. Alfred Wegener proposed the theory that all of Earth’s continents were once connected, which he called Pangaea. His reasoning behind this was that all the continents fit together like a jigsaw and that he also had proof of dead organisms on different continents that had no way of being where they were unless the continents were once one and that when they drifted apart, the fossils were separated....
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...Illinois where he received his BS., MS. and Ph.D. in Geology. Having been raised in a household with both parents as engineers, it was no surprise that science seemed to fascinate him a lot. He was one of the pioneers in advancing the process of seafloor spreading. He attempted to find the seafloor by using SCUBA gear and many other inventions made for deep sea diving. Robert Dietz is a famous geologist who studied the ocean floor and furthered our understanding of seafloor spreading. Robert S. Dietz was born in Westfield, NJ on September 14, 1914. Dietz had a long successful life and lived to be eighty. His mother Bertha and his father Louis had seven kids, of which he was the second youngest. He believed in the religion Creationism, which is the religious belief that the Universe and life originated "from specific acts of divine creation.” He had five brothers and one sister. He attended...
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...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 not see his vindication. Samples from the ocean floor were for the first time collected and analyzed. In the 1950's paleomagnetism emerged as a new tool. • Polar wandering – The migration over the surface of the Earth of the magnetic poles of the Earth through geological time (only the magnetic pole “switches” the geographic pole is always the same). A study during the 1950s showed that...
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...in density -Keep in mind: Moho Drifting Continents and Spreading Seas Plate Tectonics: Unifying theory of geology developed in 1960’s, outer layer of Earth’s crust (lithosphere, lito = rock)consists of separate plates that move around. Explains locations of: earthquakes, volcanoes, mountain belts Antonio Snider-Pelleginer: says its all together (the plate) Alfred Wegener(1880-1930): first proposed the Hypothesis of Continetal drift: The Origin of the Continents and Oceans (1915) **What evidence supported Wegener’s continental drift hypothesis?** 1. Obvious fit of continents 2. Evidence for the distribution of glaciers a. Glaciation (260-280 Ma) Striations: direction, till deposits: perimeter. If continents were connected, one large ice cap explains these observations. Climate belts from ancient environments seem to match across continents. 3. Distribution of fossils a. Each continent has unique assemblage of terrestrial species b. “Isolated” by large ocean basins -Mesosaurus, freshwater reptile lived ~286 Ma, lived in South America and Africa at the same time. c. Otherwise, fossil distribution must be explained by migrations across land bridges 4. Alignment of ancient mountain belts and rock type Evidences support Wegener’s continental drift hypothesis: 1. Fit of...
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...Quiz 8 A Question 02 1 out of 1 points | | | Which of the earth's interior layers is composed mostly of molten iron? | | | | | Selected Answer: | outer core | | | | | Question 04 1 out of 1 points | | | How does oceanic crust compare with continental crust? | | | | | Selected Answer: | oceanic crust is thinner (5-8 km) and denser (3.0 g/cm3) than continental crust (~25-35 km, 2.7 g/cm3) | | | | | Question 08 1 out of 1 points | | | The temperature in the earth's core is about | | | | | Selected Answer: | 6000 degrees C | | | | | Question 12 1 out of 1 points | | | The compositional spectrum within the group of rock-forming minerals described above extends between what end members? | | | | | Selected Answer: | felsic (light-colored, less dense) to ultramafic (dark-colored, higher density) | | | | | Question 14 1 out of 1 points | | | Which of the following best describes the textural characteristics of plutonic (i.e. intrusive) igneous rocks? | | | | | Selected Answer: | large, interlocking mineral crystals | | | | | Question 15 1 out of 1 points | | | A very large body of intrusive (or plutonic) igneous rock of felsic composition, which basically is the remant of an extinct magma chamber and is only exposed at earth's surface after a long period of uplift and erosion, is a | | | | | Selected Answer: | batholith | | | | | Question 27 1 out of 1 points ...
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...Divergent Boundaries * Divergent means to split apart. * This creates ocean floors 1) What are the major topography divisions in the north Atlantic * Continental margins, deep ocean basins, and mid-oceanic ridge. * CM: outer margins of all continents and transition to oceanic crust * DOB: b/t the CM and ocean ridge * OR: broad linear swell @ a divergent plate boundary. * Slow spreading center has a rougher terrain than a fast spreading center, which has a smoother terrain. * An ocean basin starts with a continental rift (elongated depression where the crust is thinner). Convergent Boundaries * The creation of mountains (orogensis) 2) What is not a key of terrestrial orogensis? - Diverging continental-continental plates * Volcanic Island formation - Step 1: the subducting slab partially melts creating a mantle wedge - Step 2: Melt migrates upward through the overlying oceanic lithosphere and forms a growth called a volcanic island arc or island arc * Oceanic crust goes beneath the continental crust causing the creation of a volcano on land. (Andean Type) * India collided with Asia because the lithosphere was subducting beneath Asia bringing the two closer together * These two had the same density when they collided; India was stronger so it remained intact and subducted below Asia as Asia started to rise. (Alpine-type [Himalayas]). Mass, Wasted by Gravity 3) How would you classify...
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...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 rises through a rift and cools rapidly on the surface creating new plate material and a ridge of volcanoes called the mid-Atlantic ridge. This has created Iceland which also contains rift valleys showing the plates are moving apart. The eruption of Surtsey in 1963 created a new island which further proved that land...
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...various fin fish that are intended to be farmed in this area are linked fishery exports that contribute approximately R411 million per annum in the Eastern Cape. Thus study intends to investigate the development proposal aimed at increasing the growth of the aquaculture industry within South Africa as well as conducting an investigation into the economic and environmental issues associated with the introduction of aquaculture within areas such as Algoa Bay. The objectives with the introduction of fish farms are to increase job creation within the area and more importantly to manage the dwindling stocks of wild fin fish. A cost and benefit analysis will be applied to the Algoa Bay case study in order to establish the economic costs and benefits, and to establish whether it would be economically profitable to implement fish farms. Also taking into account the advantages and disadvantages of implementing fin fish structures by looking at the impact on the ocean at large. 2. Literature Review: Aquaculture in Algoa Bay 3.1. Fish farms...
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...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 one huge land mass located in the southern hemisphere and was surrounded by one huge ocean. This modern theory is generally globally accepted, with valid evidence to back it up with, for example, the distribution of fossils, the earths geology, coal deposits and fauna and flora deposits. Figure 1.1: World map of what Pangaea would have looked like 300 million years ago. Figure 1.2: Shows...
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...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, they were later supported by the discovery of the Mid-Atlantic ridge. This ridge led to the discovery of sea-floor spreading and the understanding that the earths crust is being both destroyed and created, leading us to believe in the existence of plates and plate boundaries. Oceanic ridges are created when two plates diverge and magma rises between them from the asthenosphere, creating the...
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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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...Creation of Oahu by Volcanism Volcanoes are magnificent formations from an opening in a planet’s crust. They form when magma, volcanic ash, and gases escape from a magma chamber below the surface of the planet. Tectonic plates cover the surface of the planet and are constantly moving. Volcanoes are generally found where these plates converge or diverge. Not only are volcanoes found in these areas but also where the Earth’s crust is stretching or thinning. There are volcanoes that form away from plate boundaries in areas that are called “hot-spots”. An example of “hot-spot” volcano formation is the Hawaiian Islands. Figure 1: (Kreger, 2010) The image above shows that volcanoes are created by hot magma that rises from the Earth’s core and expels through the cracks of the upper mantle and ocean crust. The movement of the Earth’s plates forms these cracks on the surface of the ocean crust. Every Island is made of one or more volcanoes that have erupted many times and emerged above sea level. A seamount is a mountain that rises above the Ocean floor that is of volcanic origin and does not rise above sea level. Most seamounts are formed from extinct volcanoes that have been eroded and grounded back down by waves. Loihi is an example of an active seamount that is currently being studied because of its assumed Island formation. Because Loihi is located before the Island of Hawaii, it is believed that it will become an Island soon enough. Loihi is slowly moving across the hot...
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