Theory of Plate Tectonics - Geologists agree that the theory of plate tectonics departing from the movements of continents, widening the ocean floor, the movement of tectonic and volcanic activity caused by the power that comes from inside the Earth so that the Earth's surface changes / developments earth. Tectonic plates that move and rub against each other causing the continents. Such as the Asian continent, Laurasia, the ranks of the islands, and mountains. Here we will discuss about the movement / shifting of continents or drift theory.
1. Alfred L. Wagner (1880-1930) in his book Die Enstehung Und der Kontinente Ozeane (Origins Continent and Ocean) was published in 1915.
a. Evidenced the contour line equation east coast of North America and South America and the contour lines of Western Europe and Africa. Proved the similarity of geological formations along the coast of West Africa (Sierra Leone - Cape of South Africa) with geological formations east coast (of Peru - Balsia Blanca).
b. Green areas Sandria moving away from South Africa with a speed of 36 m / yr. The island of Madagascar is moving away from South Africa with a speed of 9 m / year.
c. The continent is now, once a continent called Pangaea. Continent Pangaea broke, in the southern part of moving toward the west and to the north towards the equator. Because the incident happened following matters.
- Stretch of continents and oceans on their own float.
- Atlantic Ocean is becoming increasingly widespread because of the American continent moving towards the west, causing the earth's surface in the form folds mountainous landscape in the American west coast of the north - south.
- The existence of exceptional seismic activity along faults St. Andreas near the west coast of the United States.
- Urges the Indian Ocean to the north to the Indian subcontinent pressed and raises the Himalayan mountain range.
- The state of today's continents were still moving. Can be proved increasingly widening of the gaps found in the grooves of the oceans.
2. December Cartes (1596-1650)
Fundamentals of the theory of contraction.
Due to continuous cooling of the earth we get shrinkage and wrinkles, wrinkles are caused valleys on the surface of the earth.
3. E. Suess (1831-1914)
Forward the theory of December Cartes, but E. Suess added that geological similarities found in South America, Antarctica, India, Australia due to the continent's original one continent called Gondwana. The continent today stayed the remains because the majority has sunk below sea level.
4. Theory of Plate Tectonics Tuzlo J. Wilson and Jason Morgan
Canadian geophysicist, J. Tuzlo and American geophysicist Jason Morgan, propose a scheme theory of plate tectonics in the 1960s. This theory states earth lithosphere consists of several plates hard. These plates shift and move over the softer layer called the asthenosphere.
A plate can sort the whole impact of the ocean, as the Pacific plate, or part of the oceanic plate and continental collision parts, such as the North American plate. The collision produces a new ocean oceanic mountains (row of underwater mountains formed by the skin of young ocean).
Leather old oceanic sink or tersubdaksi into the mantle at subdaksi zone, which is found in the deepest parts of the ocean, called trenches. As the plates move, they coalesce and form mountains. Plate boundaries is the most common area of earthquakes and volcanoes are most numerous.
Indonesia consists of three plates, the Indian plate or Indo-Australia in the south, in the northern part of the Eurasian plate and the Pacific plate in the east. The plates move at a speed of 3-10 cm per year. At one time the meeting between the plates will experience a shift that resulted in piling plates, folding, or broken. When this movement occurs plate issued stress or energy not less. It is this energy which resulted in a tsunami if an earthquake under the sea or ocean.
5. Theory movements Another Continent
Researchers geology (a combination of the developed countries) who conducted research at the south pole (1969-1970) Trans Antarctic base in Central, aims to prove the theory AL Wagner. From the research found the evidence as follows.
- The area 200 million years ago is the equator.
- Found the jawbone of an ancient freshwater amphibians / labyrintodont like a salamander.
- Such fossils are also found in South America and Africa. Theory movements of other continents is also assumed that 200 million years ago there was only one continent on this planet. From the development of natural science, geological knowledge, and magnitisme the longer there is evidence to corroborate the theory of continental drift.
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