Pangaea And Plate Tectonics
Pangaea And Plate Tectonics - According to studies conducted by various scientists across the world, it has been found that there was a supercontinent existing in the past. Later on over the years this super continent broke up and drifted in different directions leading to a number of continents over the globe. It is termed as the breakup of the Pangaea.
What Does Pangaea Mean
Pangaea is a Greek word. It means ‘all lands’. Around 225 million years back, the entire earth’s masses were locked together to form a Pangaea or the ‘great supercontinent’. The rest of the ocean or the world ocean was termed as Panthalessa a word in Greek which means ‘all seas’. Breakup of the Pangaea eventually took place due to tectonic forces. It led to the arranging of albeit temporary or current oceans, currents, masses of land and various continents.
All the way, towards the floor of the ocean, a yellow submarine had to be taken, by scientists, to have a better understanding about the crust of the ocean and as a result find out more on the breakup of Pangaea. Many important discoveries were made by the scientists across the world, right from the 1950s up to the 1970s.
In the paleo-magnetism field some major breakthroughs were made. Magnetic fields of the earth were studied by scientists. Rocks of different kinds were classified depending upon their magnetic properties. Accordingly their classification was made as reversed or normal. Normal magnetic properties of rocks mean that the polarity of magnetic rocks remains the same as the current magnetic field. In the case of reversed magnetic properties in rocks, the polarity is opposite to the magnetic field of the earth.
On formation of rocks, this polarity state of rocks becomes locked. Magnetic rocks having various patterns have been studied by scientists. Scientists were of the understanding that the alignment of layers within the magnetic rocks did not occur the way they were required to align indicating that there had been movement in continents. Scientists are yet to learn the various reasons for the movement of continents.
Boundaries Of Tectonic Plates
More clues were provided the striping of rocks in a symmetrical pattern. The ocean floor topography also provided a number of clues as well. The ocean floor was mapped by the scientists who found that the floor looked quite young as compared to what they had expected. Actually, a much more building up of sediment was what the scientists were expecting. A number of mountain ranges of the oceanic type were also found by the scientists. As per the paleo-magnetic studies it was revealed that the magnetic striping on both sides of the mountain ranges was quite symmetrical.
Explanation Of Magnetic Stripping
In the year 1962, an explanation on magnetic stripping and oceanic map was made available. An idea on the spreading of the sea flooring was conceived by Harry Hess, a scientist. Within the crust of the earth, is present a particular magma which spreads in a process called seafloor spreading which then separates the floor of the sea and emerges at the mountainous ranges. The sea floor was created in a new section by the magma which provides an explanation for the oceanic crust looking that young. The oceanic crust was emerging continually as a new sea floor.
Rocks that were newly created was closer to the mountain range while the location of the older rock farther away. Magnetic polarity saw a reversal with formation of every new layer, which provides an explanation of magnetic stripping.
The floor of the ocean was emerging on a regular basis, as realized by the scientists. They were understanding that expansion of the Earth was taking place. However, later on they realized that the floor of the ocean was a kind of conveyor belt. Some of the old floor of the ocean seemed to disappear into the trenches of the ocean, on the emergence of the new floor of the ocean. The process was termed as subduction.
Another thing was also noticed by the seismologists. They found that earthquakes and volcanic activities kept occurring near the trenches of the ocean and also near the ridges that kept spreading. Such evidence suggested that even if there was movement in the continents, the force, came from the crust of the ocean and not from the continents. The slabs of earth, that moved were termed as plates. A number of natural events like formation of mountains, volcanoes, earthquakes etc took place due to the movement of these earth slabs or plates. Plate tectonics is the term used for the study conducted on the movement of these plates.
It was the belief of many of the scientists that a transformation had been taking place in the crust of the earth, all through the history of 4.6 billion years. It is expected that formation of a new Pangaea is to take place around 200 billion years from now on. The convergence of all lands is expected at the time of the new Pangaea. This new breakup will ensure inevitably that planet will continue to shape itself and get reformed all over once again.
Not many people may be aware of the fact the longest mountain range of the Earth, is located under the water. This is termed as the Mid-Ocean Ridge system. These mountain ranges snake its way along 56,000 kilometres between different continents. These mountains which are seen in a range under the sea are 1200 miles wide and 12000 feet high, and wind through various oceans of the world at a distance of 40,000 miles. The valleys and mountains in this series indicate where exactly the crustal plates of the earth are drifting apart.
Various scientific studies indicated that in the solar system, the earth may probably not be the only celestial body which has been shaped by the plate tectonic forces. A latest theory has also indicated that the surface of Mars, has also been transformed all through the millennia by significant events of tectonic nature.