Do you need help writing an essay? For Only $7.90/page

Menu tectonics theory essay

‘Evaluate just how plate tectonics theory will help our comprehension of the circulation of seismic and scenic events’ In 1912, Alfred Wegener printed his theory that a one super continent named Pangaea once been with us about three hundred million years ago. He recommended that Pangaea then later split into two regions of Laurasia in the north and Gondwanaland in the southern region and that present continents were the result of further more splitting of these two terrain masses. In which the plates split are called plate limitations. Wegener’s theory of continental drift was supported by both equally geological and biological data that these areas were once joined.

The geological proof included the rock sequences in North Scotland strongly agreeing with those seen in East Canada, indicating that we were holding laid down under the same conditions in one site as well as the obvious jig observed fitting physical appearance of modern-day continents, specifically, the stick of south America fitting in the indent under west Africa.

The neurological evidence comprised of fossil studies linking several continents.

Fossil brachiopods found in Indian limestones had been comparable with similar fossils in Australia plus the fossil remains to be of Mesosaurus’ were seen in both South usa and the southern area of Africa. It is unlikely the same jesus could have developed in the two areas or that it could have migrated across the Atlantic. Despite the evidence, Wegener’s theory was unable to describe how continental movement acquired occurred. Even so from the 1940’s additional facts accumulated after the discovery from the mid-Atlantic ridge and huge oceanic trenches. Study of the ocean crust either side from the mid-Atlantic ridge suggested that sea-floor dispersing was occurring. Magnetic studies of the water floor inside the 1950’s, showed regular patterns of paleomagnetic striping around the side rails. It was learned that when lava erupts within the ocean floor, magnetic domain names within straightener rich mineral deposits in the lava are lined up with the permanent magnetic field with the earth. This fixes while the lava cools and records the earths polarity at the time of their particular cooling.

Because the polarity of the the planet reverses just about every 400, 1000 years, groups of normal and reversed polarity rubble are shown on either side from the mid sea ridges, suggesting that fresh rocks are being added equally on either part. Surveys as well established the age of the rubble and found fresh ages for places about or near the ridges and much older age range for mountain nearer towards the continental masses, demonstrating that older brown crust area is continuously being moved aside bynew crust. The discovery of sea flooring spreading resulted in the assumption that the globe must be receiving bigger nevertheless this was not the truth and the breakthrough of oceanic trenches brought about the conclusion that plates has to be being demolished at different boundaries to allow the increase inside their size by mid-oceanic ridges. Hot spots surrounding the core with the earth generate thermal convection currents in the mantle which may cause magma to rise towards the brown crust area and then pass on before cooling down and settling.

This blood flow of caos is the power of menu movement. This movement has an effect on all the plates determining all their type of boundary each with their own features and producing volcanic and seismic situations. Divergent boundaries occur along spreading centers where plates are going apart and new brown crust area is created by magma pushing up through the mantle resulting in oceanic side rails and rift valleys. Exactly where two oceanic plates are moving apart they develop mid oceanic ridges using their form motivated by the price at which the plates individual. Volcanic activity occurs along the ridge creating submarine volcanoes which at times rise above sea level helpful fairly gentle sides and often gentle breakouts. An example of this can be located in Surtsey, to the south of Iceland, and Iceland on its own. As fresh crust varieties and propagates, transform flaws occur by right sides to the menu boundary because of shearing pressure. The elements of the spreading plates on either side of these wrong doing lines may well move for different costs causing shallow focus earthquakes. Where two continental china are dispersing they generate rift miles.

The brittle crust fractures at areas as it moves apart creating a normal wrong doing where suspending wall declines down in accordance with the foot wall because of tensional pressure. A feature of the rift valley is known as a ‘graben’ which forms when a block of mountain falls among two problems and creates the area floor in addition to a ‘horst’ which can be formed when a block of rock is pushed up among two faults. This area is associated with volcanic activity as the crust is much slimmer than in adjoining areas. Concourant plate restrictions occur when two china are going towards one another. Where oceanic and ls crusts satisfy, the denser oceanic brown crust area is forced under the less heavy continental dish known as subduction. The straight down warping with the oceanic platter forms a really deep sea trench plus the continental dish edge is affected by the reverse wrong doing lines that cause flip-style of the platter to produce uplifted rock that forms Flip Mountains. Asthe oceanic brown crust area descends, the increase in pressure can result in major earthquakes along the brand of the sub ducting menu. As it descends further the surroundings become sexier and additional warmth from the scrubbing causes the rock to melt in the benioff region which starts to rise because plutons of magma. If they reach the area they contact form composite volatile volcanoes.

Eruptions can also occur offshore producing volcanic islands referred to as area arcs. Exactly where two types of the same plate meet they produce collision areas by which the compression from the two discs results in the folding with the plate to form Fold Mountain range. As there is little subduction, there is no scenic activity nevertheless the movement of plates can easily trigger shallow-focus earthquakes. Conventional plate limitations occur the moment two crustal plates slide past each other and the activity of the china is parallel to the menu boundary. The movement in the plates makes stresses involving the plate sides and as they will rub past each other the discharge of friction triggers short focus earthquakes. However while there is no subduction, there is no scenic activity. The very best known example of a old-fashioned boundary may be the San Andreas Fault in California, where the pacific and North American plates move seite an seite to each other.

Scenic activity it does not occur along any menu boundary is most likely the result of many a fault lines and hot spots underneath the crust. Alfred Wegener’s theory allowed us to gain insight into the potential creation of our tectonic plates and the boundaries. The evidence provided by wegener’s theory and the record of paleo-magnetism after the ocean floor reinforced the idea that the tectonic dishes are moving. Supported by the theory of convection currents, the movement of the plates assists our comprehension of the distribution of seismic and scenic events by allowing us to identify varying plate restrictions that create different features and as a result trigger these incidents. This clarifies their circulation, as events such as these can be found in areas above plate boundaries, apart from the odd one which can occur over many a fault lines or hot-spots caused by the movement of plates.


Prev post Next post