Assignment 2

doc

School

Capella University *

*We aren’t endorsed by this school

Course

112

Subject

Geology

Date

Oct 30, 2023

Type

doc

Pages

Uploaded by MajorGuanacoPerson438

Life Science Oceanography Reasons why dumping of radioactive waste in the Mariana Trench is; a good idea and why it is a bad idea too. Name Institution Subject Instructor Date

Life Science Introduction Mariana trench (Marianas Trench) is the deepest part of the world’s oceans, and the deepest location on the surfaces of the earth crust. It has maximum depth of about 10,911 metres (35,798 feet; 678 miles), and located in the Western north of Pacific ocean, to the east and south of the Mariana Islands, near Guam. The trench forms the boundary between two tectonic plates. At the bottom, the water exerts a pressure of 108.6 Pa, over 1000 times the standard atmospheric pressure at se level (The Mariana Trench, 2003) Plate Tectonics is a description of the surface of the earth. The interior of the earth, called the mantle, is hot, molten lava. The earth’s solid crust, which is in pieces, floats on this magma. As hot magma rises through cracks in the crust, it pushes the pieces of crust apart. In other places, pieces of crust are forced together, where they buckle to form mountains. The oceanic crust is much heavier than the continental crust, so when these plates crash into each other, the oceanic plate plunges downward toward the molten mantle, while the lighter, continental plate rides up over the top. The forces driving the two plates together are really intense, so the underlying oceanic plate (the 'subducted' plate) creates a trench where it drags the edge of the continental crust down as it descends underneath (Fryer 1993).

Life Science Reason to why the Mariana Trench should be used for Dumping of radioactive waste: The earth's crust is formed of large solid tectonic plates. These large tectonic plates are formed at ocean ridges and slowly migrate until they reach "subduction" zones at which location they re- enter the earth at an average rate of six (6) cm per year (Fryer & Smoot 1985). With the waste placed or bored into the basaltic layer of the oceanic crust beneath sediments overlaying the basaltic layer at or as near as possible the edge of the subduction zone, the crustal downwards movement of the tectonic plate would carry the waste into the interior of the earth. Many millions of years would be required for the waste to circulate through the earth's mantle before it could reemerge in a diluted, chemically and physically altered form at an oceanic ridge. Reasons to why the Mariana Trench should not be used for Dumping of radioactive waste: Waste implanted in ocean sediments would also be subjected to natural upheavals and to mechanical perturbation once they eventually migrated to a subduction zone, as all sea beds are so predestined, as a portion of the sediment would be scraped off along the abutting continental edge. Wastes could then migrate back to the biosphere because of this abrasive action. Even if the sediment and embedded waste were subducted, the waste could return to the environment because of andesitic volcanism adjacent the subduction zone. This is so because it is understood that at a depth of near one hundred (100) kilometers within the earths crust; heat and pressure causes water to be driven from the crystalline structure of the subducted sediments (Hussong & Fryer 1985). The heat generated by this phase change collective with the temperature of the rock at that depth causes some of the sediment and overlaying rock to melt and to rise to the surface as volcanoes. Waste melted along with the sediment could thereby return to the biosphere dissolved in the molten rock creating detrimental environmental conditions.

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

Life Science Conclusion: The punch-line is that, the Sub seabed Nuclear Waste Disposal Program (1975-1985) concluded that the Marianas Trench is too prone to belch and burp, with earthquakes and volcanoes, to rely on it to get the waste to the Earth’s mantle safely and consistently. Therefore, we should think of better ways to dump our radioactive waste rather than the Mariana Trench. References: 1. Fryer, P., 1993, The relationship between tectonic deformation, volcanism and fluid venting in the southeastern Mariana convergent plate margin, Proc. JAMSTEC, Symp. Deep Sea Res. 9, 161-179. 2. Fryer, P. and N. C. Smoot, 1985, Processes of seamount subduction in the Mariana and Izu-Bonin Trenches, Mar. Geol, 64, 77-90. 3. Hussong, D. M. and P. Fryer, 1985, Forearc tectonics in the northern Mariana arc, in Formation of Active Ocean Margins, edited by N. Nasu, Terra Scientific Publishing Company, Tokyo, 273-290. 4. The Mariana Trench, 2003. Explore the Mariana Trench. Retrieved on 7 th Nov.2009 from http://www.marianatrench.com/