...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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...magma. Each individual landform, such as the Yellowstone Caldera volcano, is formed by specific processes and present distinct interactions with their surrounding environment. This as well as the rarity of it as a landform will be discussed in this report. 2.0 Table of contents: Title page: ………………………………………………………………...p1 1.0 Abstract: ......................................................................................p2 2.0 Table of contents: ………………………………….……………..…p2 3.0 Introduction: …………………………………………….………..…..p3 4.0 Structure and composition of Yellowstone volcano: ………….…p3-p4 5.0 Yellowstone volcano processes: ……………………………….….p4-p5 6.0 Yellowstone volcano interactions: …………………………….…...p5-p6 7.0 Rate of recurrence of caldera volcanoes as a landform: ……….p6 8.0 Conclusion: …………………………………………………………..p6 9.0 References: …………………………………………………………..p7 3.0 Introduction: The purpose of this report is to research and present reliable and detailed information on the Yellowstone caldera volcano. Through the examination of a range of published journal articles and internet sites on the topic of volcanic landforms, and more specifically on the Yellowstone caldera volcano, this report describes the Yellowstone caldera landform and goes into detail on four main topics of the volcano. These topics include the structure and composition of the selected volcano, its specific processes as a landform, how it interacts with other landforms...
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...put that into perspective, the Netherlands is about two and a half times the area (nationsonline.org, 2015), but has nearly 60 times the population at nearly 17 million inhabitants (Countrymeters.info, 2015). This is despite the fact that the cultural history of the country can be dated back to about 800AD, and settlement occurred from 870-930AD. However, the true history of Iceland goes much beyond than that. Iceland has a rich geologic history that dates back thousands, if not millions of years, that makes it one of the most fascinating countries in the world. In this essay, we will explore the origins of Iceland from its formation to its current size, some of the unique features that Iceland has that most countries do not have, as well as a few significant geologic events in Iceland that have shaped Icelandic and even global events. Formation of Iceland Diagram 1 from classroomatsea.net Diagram 1 shows a general idea of how Iceland was formed. Iceland is situated in the centre of the Eurasian and the North American plate. The two plates move away from each other due to the magma undercurrents, due to the convection effect from the earth’s core. This divergent plate movement effectively opens up a fissure for a magma plume to escape from the earth’s mantle to fill the space between the plates. The magma plume, which originates from the hotspot, has significantly higher temperatures that the surrounding magma, which gives the plume its buoyancy, which effectively...
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...pose a threat to humans and their lifestyle. Therefore, a tectonic hazard is one which involves tectonic processes being hazardous to humans. In the first part of my essay I will be explaining exactly what is meant by tectonic processes and will be referring to the relatively new concept of Plate Tectonics which, although being presented as a theory in 1912 by Alfred Wegener, was not actually taken as the standard model until the late 1960’s and even then was being criticized by many learned scholars into the 1980’s. I will then explain what the main types of hazards are in tectonics, namely volcanoes (openings in the earth crust from which material from below the earth’s surface can be ejected) and earthquakes (movement in the earth’s crust that causes shaking of the ground above). However, there are many more hazards that can be associated with these two, namely tsunamis and from volcanoes, pyroclastic flows, lahars and volcanic gases. What causes these hazards should be explained in my explanation of plate tectonics. Throughout my assignment, I will be using many examples of tectonic hazards from around the globe, but will be focusing on certain case studies to try and explain exactly what causes tectonic hazards. I will be using the San Andreas Fault in the western part of North America as an example of transform plate margins*, the Himalayas as an example of fold mountains created by collision zones of convergent plate margin* between two continental plates, Krakatoa as...
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...1. Explain the relationship between continental drift and the formation of the Earth’s Oceans? The relationship between continental drift and the formation of Earth’s Oceans comes from the plate movement that occurred in Earth which is called plate tectonics. All of the landmasses were grouped together into one vast supercontinent called Pangea. Over millions of years the land started to split into many different countries and it also divided Panthalassa, the single great ocean that surrounded the continent Pangea, into many different oceans and that’s why now we have different oceans and countries around the world. 2. How did volcanoes affect the origins of the seas? Volcanoes affected the origins of the seas because volcanoes poured huge amounts of steam into the atmosphere and as the Earth cooled down the steam turned to water vapor that condensed as droplets and began to fall as rain. This downpour lasted for many thousands of years filling great hollows in the land and thus forming the world's first seas. 3. Describe the hydrologic cycle as if you were a particle of water going through it. If I were a particle of water traveling through the hydrologic cycle I would first float on top of the ocean and be absorbed by the sun’s heat. I would be lifted up into the air as water vapor and as the air cools, I would join up as a water droplet that form clouds. As I get into the cloud, when it gets too full I would fall back onto the ground as rain or a...
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...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 one huge land...
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...Cinder Cone volcanoes are created by just one vent in the Earths outer crust. These volcanoes are the most common, only reach about 300 meters above the ground and appear in Western North America. According to Universe Today, one of the most famous, or infamous, volcanoes erupted out of a Mexican corn field in 1943. This volcano reportedly erupted for 9 whole years, covering adjacent towns with volcanic ash. Composite volcanoes are made by an accumulation of eruptions. The layers of these volcanoes are formed by hardened lava, tephra, pumice, and volcanic ash. Composite volcanoes are most commonly found in the Ring of Fire, a major area in the basin of the Pacific Ocean featuring 425 volcanoes. Mount Fuji, the tallest volcano in Japan, is...
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...1. Explain the relationship between continental drift and the formation of the Earth’s Oceans? The relationship between continental drift and the formation of Earth’s Oceans comes from the plate movement that occurred in Earth which is called plate tectonics. All of the landmasses were grouped together into one vast supercontinent called Pangea. Over millions of years the land started to split into many different countries and it also divided Panthalassa, the single great ocean that surrounded the continent Pangea, into many different oceans and that’s why now we have different oceans and countries around the world. 2. How did volcanoes affect the origins of the seas? Volcanoes affected the origins of the seas because volcanoes poured huge amounts of steam into the atmosphere and as the Earth cooled down the steam turned to water vapor that condensed as droplets and began to fall as rain. This downpour lasted for many thousands of years filling great hollows in the land and thus forming the world's first seas. 3. Describe the hydrologic cycle as if you were a particle of water going through it. If I were a particle of water traveling through the hydrologic cycle I would first float on top of the ocean and be absorbed by the sun’s heat. I would be lifted up into the air as water vapor and as the air cools, I would join up as a water droplet that forms clouds. As I get into the cloud, when it gets too full I would fall back onto the ground as rain or a...
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...• They are low, with mildly sloping sides. • They are form because of eruptions of runny, thin lava. • Eruptions are usually regular but relatively mild. Composite volcanoes • Made up of alternating layers of ash & lava (other volcanoes consist of just lava). • They’re typically located at destructive boundaries. • The eruptions from these volcanoes tend to be a pyroclastic flow (a mixture of hot steam, ash, rock & dust.) rather than a lava flow. • A pyroclastic flow can roll down the sides of a volcano at extremely high speeds & with temperatures higher than 400°C. Volcanic eruptions can have overwhelming effects on the environment & people Although, unlike earthquakes, volcanoes can also have a positive impact on an area. Positive + & negative - effects of an eruption Positive + Negative - Extra income could be brought to an area, because tourists are attracted to the dramatic scenery created by volcanic eruptions. Volcanic eruptions usually lead to many lives being lost. Valuable nutrients may be provided to the soil when lava and ash (from the eruption) are deposited and breakdown. This is good for agriculture as the soil becomes very fertile. Lahars...
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...continents were once all joined together in an ancient super continent called Pangaea. Land masses had drifted apart until they got to a certain position. Used 4 different pieces of evidence to help support his theory: 1. Continental Fit – If you placed certain continents together they look like they should/could have been joined together at some point. For example western seaboard of Africa and Eastern sea board of South America. 2. Geological Evidence – Rocks of similar type and age sharing the same formation can be found in South East Brazil and South Africa, which were believed to be joined. Also similar glacial deposits found in the Antarctica, South America and India. 3. Climatological Evidence – Similar coal deposits have been found in places such as Antarctica, North America and UK, all of similar age and all formed in tropical conditions. Neither of these places is still tropical therefore the coal must have drifted apart. 4. Biological Evidence – Fossil formations can be found on either side of the Atlantic. An example of this is the Mesosaurus, this reptile could not fly, however its fossils were found only in South America and South Africa. Therefore they must have been joined; otherwise the fossils would not be in the same place. * Paleomagnestism - The first piece of evidence to support Wegener’s Theory came from the discovery of a ridge of mountains running along the middle of the Atlantic Ocean known as the Mid Atlantic Ridge. 2 British Geologists, Vine...
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...Rumble Begins Erupting in a varied amount of locations, volcanoes cause those living nearby to change their way of life and adjust to the environment that may have been affected by a recent eruption. These explosive lava chambers have been erupting for an extensive amount of time and continue to do so today, some in more locations than others. Volcanoes affect both the people and environment in a positive and negative way, such as a modification in scenery, increase in soil deposit, and the adaptations of people’s lifestyle to revolve around the eruption. A change in scenery can be both a positive and negative influence on the environment from the formation of beautiful sceneries over a period of time the ash polluting and darkening anything in its reach. The eruptions allow the ground around the volcanoes base to eventually turn into something visually pleasing depending on the area of the volcano. An example of this is in Hawaii which includes “well vegetated volcanic terrain and rainforest” (On the Slopes of Mauna Loa, Hawaii Island 9). The volcanoes here allow the terrain to turn into something worth sightseeing. While in other locations, volcanoes tend to destroy the ground around it. During some eruptions, the lava that erupts from it turns into fires which then demolishes anything surrounding it. That also affects any life in the...
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...Introduction Geomorphology regards the understanding of landforms and changes that take place on the earth. Modern day geomorphology is founded upon the arguments coined by ancient and medieval scholars. Such scholars included Herodotus, (485-425BC) and Aristotle (382 – 322 BC). Each of these philosophers had reported their own findings regarding diverse geomorphological phenomena. Although the scholars might have agreed on various aspects, there was immense criticism; thus the divergent claims. In this essay, I will briefly compare and contrast Herodotus’ and Aristotle’s arguments in some of the ideas that led to the development of modern geomorphology. River Siltation Both Herodotus and Aristotle present arguments in regards to river siltation. Herodotus first notes that there were yearly increments silt and clay deposits in the Nile River on its flood plains. He explains that the Nile River floods every year, and in the process, it irrigates the flood plain along either bank and deposits fresh silt along its banks. He noted that the Nile has three distinct regions (Rennell, 2011).. He further explained that flood waters from the White Nile flow through an enormous marsh called the "Sudd" in the southern part of the modern country of Sudan, and arrive later and more slowly than the flood waters from the Blue Nile and the Atbara River. This contribution was crucial in determining the modern day irrigation along the Nile as well as determining where people could...
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...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 belt principle. Earlier theories (that still have some supporters) propose gradual shrinking (contraction) or gradual expansion of the globe.[3] Tectonic plates are able to move because the Earth's lithosphere has greater strength than the underlying asthenosphere. Lateral density variations in the mantle result in convection. Plate movement is...
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...between these plates, it would correlate significantly with the distribution of volcanoes around the world. These plates are either continental (The North American Plate), or oceanic (The Nazca Plate). Tectonic plates are powered by convection currents, which is the circular movement of magma within the mantle. These currents are powered by the core, which heats the magma, causing it to rise, cool and fall back down. This circular motion causes the plates, which float on the mantle, to move. The entire outer surface of the planet is divided into these plate formations, roughly 30 in total, which vary in size from over 100,000,000 square miles for example The Pacific Plate to the Galapagos micro plate at 12,000 square miles. The individual plates are separated by fault lines which extend from the surface all the way to the asthenosphere, at which point the fault disappears due to the plasticity of the rock that exists there. The earth's plates are moved by convection currents in the mantle caused by localised concentrations of radiation and heat from the earth's core. The plates are constantly in relative motion to each other, but this motion is extremely slow due to the incredible amount of mass being moved, friction, and the high viscosity of the asthenosphere. Volcanoes represent spectacular releases of energy from inside the earth's crust and upper mantle. There are about 500 active volcanoes which are closely associated with...
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...Explain the formation of a hot spot. (7marks) Hot spots are anomalies in the pattern of volcanic activity upon plate margins. They are often in the middle of plates. A hot spot can be described as a small area of the earth’s crust where an unusually high heat flow or plume is associated with volcanic activity. Of approximately 125 hot spots thought to have been active over the past 10 million years most are located well away from plate boundaries. It is the fact that they have posed so much trouble for plate tectonic theories, as they don’t fit with the general trend that most seismic and volcanic activity happens at margins. There are several examples of volcanic activity away from plate boundaries such as Yellowstone national park. These hot spots are formed by huge columns of up swelling lava because of radioactivity within the earth, these columns are known as plumes. The plume of plastic molten rock that pushes upwards; causing pressure to drop and the plastic thin rock to become molten, melting and pushing through the crust above. These plumes lie in fixed positions under tectonics plates. As the plate moves over the hot spot, the upwelling lava creates a steady succession of new volcanoes that migrate across the plate. These plumes can be up to 1000km across. The emperor sea mount chain is a good example of plume activity; showing the variation of activity within the succession as the plates move over the plume. This chain extends 5000km along the Pacific Ocean...
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