Discuss about the Tectonic Plates and Mantle Convection.
The surface of the earth is made up of several large sized plates. These plates are continuously floating on a liquid. This liquid is reserved below the earth’s surface and is termed as magma. It has been found that these plates are constantly moving at a very slow speed. The phenomenon of moving of these plates is termed as plate tectonics. In order to determine the plate movements more preciously, continental drift and sea- floor spreading theories are considered (Zhong, 2011).
Continental drift theory advocates that the continents of earth are changing their position over a period spanning thousands of years. Moreover, the tectonic plates are present in the lithosphere of the earth and are generated of solid curst which is floating on the magma. The density of these solid curst plates is very low as compared with the magma and thus, the density difference allows them to float on surface. There are convection currents flowing in the magma which cause the pulling, stretching and pushing of the plates and finally the movement of tectonic plates (Tomecek, 2011).
The sea floor spreading advocates that middle portion of the ocean is moving very slowly but in the opposite direction. This causes a direct push on the tectonic plates and thus, they are moving away. There are both thin and thick oceanic crusts that are present in the ocean. When convection is incurred in the mantle of the earth, then it produces hot magma. This magma starts pushing the crust, and finally creates a ridged crest. This happens in the depth of the sea water. The mantle of the earth is moving away from the generated ridge which creates sufficient tensions and finally breaks the ridge. This cracked ridge generates rift zone and results in minor earthquake (Zhong, 2011). This is indicated below using the example of Mid-Atlantic Ridge.
The major effects of tectonic plates are eruption of volcanos, glacial erosion, stream erosion, earthquake, and tsunami. Earthquake is the vibration and continuous shaking of the earth. In this process, majority of the elements in the affected area are pulled up into the earth and the formation of the fossil fuels starts at the depths of earth. These plates play an imperative role in the process of volcanic eruption. When the tectonic plates are moving in the opposite direction then a significant amount of hot magma arises from the surface of the earth; It has been observed that most of the active volcanos are situated near the convergent plate boundaries of the earth (Zhong, 2011). Usually continuous subduction is incurred in these places specifically near the pacific region. Additionally, nearly 75% of the lava erupted from the volcanos are generated due to the mantle spreading process (Miller, 2016). This volcanic lava is a source of various ores and minerals and elements that are of high economic use. Further, it is essential that the planet must have a surface for habitability (Cockell, 2015).
Moreover, volcanoes support the green house effects which keep the planet warmer which is favourable condition for plants to grow. Subduction of the carbonate elements helps to generate the fossil fuels and ores under earth. It is an ingrained assumption that a planet must have tectonic plates in regards to have habitability place for a long term (Tomecek, 2011). Plate tectonics phenomenon only occur in our planet in the solar system and thus topography motion of earth surface losses the internal heat which helps to maintain the temperature equilibrium of the planet, which is the prerequisite to establish a habitable place. It is a major driver and enabler of the carbon-silicate cycle, which is an essential cycle for the sustainability of the environment. The maintenance of the carbon-silicate cycle has profound implications for the maintenance of suitable carbon dioxide levels on earth so as to aid life. Any major imbalances in the process could render the earth too hot or too cold for human habitation (Miller, 2016).
The role of the tectonic plates in the above process can be understood as follows. The carbon stored in the limestone is not able to free in a ready manner. In order to ensure the same one of the key process is subduction which leads to the carbonate rock melting as these are pushed towards the mantle. The carbon escapes which makes way to the surface through the gases released by a volcano. In the short run even though focus is on the release of carbon through anthropogenic reasons but in the long run, it is essential that the carbon trapped in the form of carbonate formations needs to be freed or else there would a drastic fall in the carbon dioxide levels which may onset an ice age. The presence of tectonic plates ensures that the long term carbon cycle is maintained thus making our planet habitable (Cockell, 2015). Tectonic plate movement results in replenishment of a host of the nutrients which is a vital requirement for supporting life of any living being. Chairman of ESA’s scientific advisory committee and the director of the “German Space Research Centre Institute of Planetary Research has advised that a strong relationship between the plate tectonic and habitability of a planet (Miller, 2016).
It may be fair to conclude from the above discussion that while the most visible and known impact of plate tectonics may be in the form of earthquakes and volcanoes, but tectonics plates are at constant and invisible action and making this planet habitable by maintaining equilibrium in key geochemical processes. This goes a long way in providing a stable crust along with a stable and ambient physical environment where life can not only sustain and flourish. Hence, any major shifts in plate tectonics could lead to serious implications for life on the planet (Tomecek, 2011)
Cockell, S. C. (2015) Astrobiology: Understanding Life in the Universe. 2nd edn. Sydney: John Wiley & Sons.
Miller,T. G. and Spoolman, S. (2016) Living in the Environment. 19th edn. Boston : Cengage Learning.
Tomecek, S. (2011) Plate Tectonics. 4th edn. New York: Infobase Publishing.
Zhong, S. (2011) Tectonic Plates and Mantle Convection. 6th edn. Michigan : University of Michigan.