While much has been hypothesized regard a sill in the context of geology, it is of the essence to note that it mainly refers to an intrusion that is tabular in nature that often intrudes on older deposits of sedimentary rocks. In metamorphic rocks, sills often intrude on along the directions of foliation. Many at times, the term sill and concordant intrusive sheet have been used interchangeably. This is a significant indicators that sill does not apply across all pre-existing rocks. On the contrary, dikes, which is often used interchangeably with discordant intrusive sheets applies across all older rocks. For this purpose, a sill should not be confused to mean the same as a dike (Hill 22). Even so, sills and dikes are connected in that sills are often fed by dikes. Exceptional case where sills are not fed by dikes includes cases when the sills are found in unusual locations, whereby they form vertical beds that are often directly attached to a magma cradle.
The fact that the sill between the basins in the current case is 3800 metres is a clear indicators that underwater tectonic movement of the two plates are merging towards each other. The movement of the two plates emanate from the fact that the lithosphere (the outer crusts of the earth) comprises various tectonic plates. Evidently, these plates oscillate on the asthenosphere, which is often referred to as a hot flowing mantle layer. The heat emanating from the asthenosphere enhance the creation of convectional currents, which cause the tectonic plates to move several metres annually relative to each other (Lane & Gilbert 82). In the current case, it can be deduced that the convectional currents have made the plates to move while converging towards each other. Therefore, it can be hypothesized that as the two plates converge towards each other, a plate boundary will eventually develop. Precisely, there are various types of plate boundaries. In this case, the fact that the plates are moving towards each other means that the type of plate boundary that will eventually be created is a convergent plate boundary (Jochum & Raghu 37). Convergent plate boundaries are often formed when one of the plates moves beneath the other plate through a process commonly referred to as subduction. Subduction process results in the formation of deep trenches, whereby it may precipitate the occurrence of earth quakes.
Tectonic movements of the current plates towards each other differs from the case of the Caribbean and subtropical Atlantic plates. The difference noted between these plates is because of the subduction zone emanating from the tectonic movements. Fauna in these deep sea areas will have to be able to survive between bathypelagic and abyssopelagic zones. Speaking of bathypelagic zone, this connotes to the deeper zone of the ocean, where the ocean appears pitch black (Malek-Madani 9). However, the appearance varies because of the existence of bioluminescent organisms that are present occasionally in the ocean. In the bathypelagic zone, living plants do not exists, but animals living in this zones are often reliant on detritus foods that fall from the uppers zones of the ocean (Affholder & Valiron 64). In addition, the animals living in this zone prey on each other as a survival mechanism. On the other hand, abyssopelagic zone, is the lower zone of the bathypelagic zone that is often referred to as the bottomless zone. This zone is characterized by the minimal existence of living organisms. In fact, only a few species such as sea pigs and swimming cucumbers are able to survive in this zone.
There is almost no light penetrating the region between bathypelagic and abyssopelagic zones. Therefore fauna surviving in this zone utilized different sensory organs instead of eyes. The pressure is very high between bathypelagic and abyssopelagic zones as ocean pressure increase by about 1 atp per 10 meters underwater, so these animals must have evolutionary features that endure high pressure. It is very likes that the temperature at this area is about 0 to 4 degrees. Therefore, animals surviving at this regions should be cold blooded and have adaptive features to survive at this extremely harsh environment (Kearey et al. 16). We would find relic species at slightly higher levels, such as around or above 3600m.
Work Cited
Affholder, M., & Valiron, F. Descriptive Physical Oceanography. London: CRC Press, 2001. Print.
Aretxabaleta, Alfredo L, Gregg R. Brooks, and Nancy W. West. Project Earth Science: Physical Oceanography. Arlington, Va: NSTA Press, 2011. Print.
Hill, M N. The Sea: Ideas and Observations on Progress in the Study of the Seas. Mambridge, Mass: Harvard University Press, 2005. Print.
Jochum, Markus, and Raghu Murtugudde. Physical Oceanography: Developments since 1950. Berlin: Springer, 2006. Internet resource.
Kearey, Philip, Keith A. Klepeis, and Frederick J. Vine. Global Tectonics. New York, NY: John Wiley & Sons, 2013. Internet resource.
Lane, S J, and J S. Gilbert. Fluid Motions in Volcanic Conduits: A Source of Seismic and Acoustic Signals. London: Geological Society Pub. House, 2008. Print.
Malek-Madani, Reza. Physical Oceanography: A Mathematical Introduction with MATLAB. New York: CRC Press, 2012. Print.
