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Describe history of earth
Earth's layers and plate tectonics
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Our Earth was formed 4.6 Billion years ago. This formation is partly due to the colliding of tectonic plates found under the Earth’s crust. These plates have greatly impacted the way in which the Earth’s outer layer looks and the type of terrain found across its vast surface. One example of these plates at work are volcanoes. Volcanoes are formed through the process of volcanism. This process occurs when “magma- a mixture of molten rock, suspended mineral grains, and dissolved gases formed in Earth 's interior — is forced to the surface.” (Reed,2013) The concept of isostacy is the “ideal theoretical balance of all portions of Earth’s lithosphere as though they were floating on the denser underlying layer is isostacy.” (Reed, 2013) When considering …show more content…
For example, in the Earth’s crust there is a limit to the total weight each point of the Earth’s surface should meet. In mathematical terms, this concept of equilibrium is defined by the “depth of compensation” which is about 70 miles below the Earth’s surface. In short, for the Earth’s crust to hold equal mass and pressure, there must be an equal amount of mass everywhere. Isostacy controls the local and regional elevation levels of continents and the ocean floor in incongruence with the total weight their underlying rocks can maintain. Often times, this phenomena and the behavior exhibited by the plates is compared to an iceberg floating at sea in which the greater mass is submerged. Additionally, gravity plays a huge part in understanding the amount of pressure the surface must undergo in order to make such movements occur. For example, as gravity pushes down on the Earth, the plates begin to move causing isostacy to create equilibrium across the entirety of the planet. For years, scientists have attempted to explain why this phenomena occurs in relation to the thickness of the earth, gravity and land density. Not until scientists John Fillmore Hayford and John William Bowie did we have a concrete understanding of isostacy and its processes. Hayford and Bowie “were able to prove that the anomalies in gravity relate directly to topographic features. This essentially validated the idea of isostasy, and Hayford and Bowie further established the concept of the depth of isostatic compensation. Both gentlemen published books on isostasy and geodesy. Hayford was the first to estimate the depth of isostatic compensation and to establish that Earth has an oblate spherical shape (a bowed or ellipsoid sphere) rather than a true sphere.” (Editors of Encyclopedia Britannica,
Ultimately the development of previous inferences and observations which have developed our current model for the Earth’s composition and interior structure are a key concept in understanding our future developments towards resourcing our planet and understanding how it works to a further degree.
Earthquakes are a natural part of the Earth’s evolution. Scientific evidence leads many geologists to believe that all of the land on Earth was at one point in time connected. Because of plate tectonic movements or earthquakes, continental drift occurred separating the one massive piece of land in to the seven major continents today. Further evidence supports this theory, starting with the Mid-Atlantic ridge, a large mass of plate tectonics, which are increasing the size of the Atlantic Ocean while shrinking the Pacific. Some scientists believe that the major plate moveme...
Basalt forms due to the partial melting of the layer of the mantle called the asthenosphere. The asthenosphere is the plastic zone of the mantle beneath the rigid lithosphere. Mantle plumes coming from the mesosphere can cause the asthenosphere to melt with heat or even if pressure decreases, which is called decompression melting (Richard 2011). The magma that forms from this melting is mafic magma that solidifies once it reaches the earth’s surface and cools quickly. The above process mainly occurs mainly during intraplate igneous activity which is the main explanation for volcanic activity that occurs a long distance away from a plate boundary. If the tectonic plate above the mantle plume is moving it can create a string of volcanic activity such as in Hawaii. See Fig 2.
For example when he writes about how the axes of each continent affects how well ideas and domesticated crops and animals flow or spread through the continent. This discussion had made lots of sense for me and is yet another idea that supports his theory. "At the one extreme was its rapid spread along east-west axes: from Southwest Asia both west to Europe and Egypt and east to the Indus Valley (at an average rate of about 0.7 miles per year); At the opposite extreme was its slow spread along north-south axes: at less than 0.5 miles per year, from Mexico northward to the U.S. Southwest; at less than 0.3 miles per year, " This example shows how east to west axes allow for a faster diffusion of crops and animals. But the north to south is very slow compared to the other. This helps explain why Eurasia had developed the quickest and the America and Africa lagged behind." For example, Portugal, northern Iran, and Japan, all located at about the same latitude but lying successively 4,000 miles east or west of each other, are more similar to each other in climate than each is to a location lying even a mere 1,000 miles due south." This line tells us why Eurasia was able to develop so fast. That is because it has an east to west axes which means animals and crops can more wildly thought the same land due to there being large amounts of land with the same latitude. While the Americas
Island arcs form as oceanic plate subducts under oceanic plate. Volcanism is concentrated in an arc of volcanoes, generally approximately located above the leading edge of the subducting plate. A trench often forms where the slabs meet and subduction begins. On the non subducting slab a series of basins form, with a fore-arc basin nearest the subduction/trench, then the main arc, and a back-arc basin on the far side (Mitchell and Reading, 1971; Frisch, Meschede and Blakey, 2010).
From modern examples and records we know that volcanic activity can set of a chai...
Volcanism is a major part of the Galapagos and their formation. The island chain is positioned on the Nazca Plate, which is subducting beneath the South American Plate at a geologically rapid pace of 2.5 inches per year. In addition, this Nazca Plate is located directly on top of the Galapagos Hotspot. It is here that mantle plumes melt Earth’s crust, creating volcanoes as a product. The oldest island was first shaped by this ...
Super volcanoes are formed when magma rises from the mantle to create a scorching reservoir in the Earth's
After Galileo found out the moon wasn't flat, he began mounting a body of evidence that supported Copernican theory and contradicted Aristotle and Church doctrine. In 1612, he published his Discourse on Bodies in Water, refuting the Aristotelian explanation of why objects float in water, saying that it wasn’t because of their flat shape, but instead the weight of the object in relation to the water it displaced.
The subsection about Archimedes describes Ancient Greece, and how countless citizens of the area yearned to know how their world functioned. They depended on mathematicians and philosophers to inform them of the structure of the universe. One of the most renowned philosophers of the time, Archimedes of Susa, became one of the forefathers of calculus with his method of finding the area of shapes that were previously impossible to figure (Harding, 1976). Harding and Scott focused mainly on this method of Archimedes, which was known as the “method of exhaustion,” (Harding, 1976). By his method, Archimedes could calculate the areas of formerly impossible figures by using infinitely smaller, possible shapes within the impossible one. An example that the authors claim to be extremely well-known was his approximation of the area of a circle using tangent lines and po...
Tarbuck & Lutgens, authors of our textbook, present the reader with an uniformitarian perspective on geology (pp. 324-326). There was so much more that I was unfamiliar with such as all the science that scientist uncovered from their studies and research. Though there are differences as to how creation came about, there is still plenty of knowledge gained from the efforts and hard work from men who gave their lives so that mankind would be all the better for it. The science that went into developing instruments for testing purposes, for exploration, and to further research efforts to answer the mysteries of creation continues to be in the hearts and minds of people that God
Since this time, the term uniformitarianism has been manipulated, altered, and redefined to mean a variety of different meanings spanning various fields of science. However, in the field of geology, uniformitarianism (or actualism) means something very specific. The term does not denote that every process we see before us now has been going on for eons, rather it stand for the chemical and physical laws that govern today’s processes. Evidence shows that the ancient atmosphere of the earth is extremely different from the one we can see today. There fore, the means by which erosi...
The interior structure of the earth is made up of crust, the mantle and core (inner core and outer core). Earthquakes occur on the crust. Crust forms the external layer of the earth surface. On the crust, the plate tectonics forces are in charge of causing the abrupt earth movements. Due to the existence of an immense temperature and concurrent pressure difference in the outer layer and inner layer of the earth, convection currents occur at the mantle. This energy results from overwhelming decomposition of radioactive substances contained by the rocks found at the interior of the earth. The developed convection currents lead to movement of lava; cold lava finds its way to the interior of the earth crust, while the molten lava which is generally hot, leaves the interior of the earth to the outside of the earth crust. These kinds of circulations occur at different locations of the earth surface and consequently results in segmentation of the earth due to movement in different directions.
Volcanoes are formed when magma is expelled from the Earth’s surface, resulting in volcanic eruptions consisting of ash and lava. Over time, the lava cools and forms into rock on the Earth’s surface. Whenever an eruption occurs, the newly-formed rock from the lava layers continuously until the volcano takes its shape. Volcanic eruptions have taken place for thousands of years, and even today, according to the U.S Geological Survey (2010), there are approximately 1500 active volcanoes located throughout the world.