Assignment 3 After reading the article, compose a letter to editor explains the
ID: 295080 • Letter: A
Question
Assignment 3 After reading the article, compose a letter to editor explains the real reason for the movement of the continents. In letter must includes references to the asthenosphere and heat source that drives the convection cells in the asthenosphere Article: TUCSON, AZ-Saying that a tectonic shift in the landmasses' relationship was the likeliest source, geologists at the University of Arizona told reporters Monday that the continents may have drifted apart after an emotional falling- out. "It appears from the geologic record that the continents separated after an impassioned disagreement," said Dr. David Sarlow, explaining that the rift probably began around 200 million years ago when massive portions of the Pangea supercontinent broke up and moved to different hemispheres. "Various internal pressures and friction continued to cause the continents to split further into the isolated landmasses we know today. They were practically inseparable for eons and, even now, you can tell how close they were in the past." Sarlovw went on to say, however, that the Isthmus of Panama still connecting North and South America may suggest at least a narrow hope of reconciliationExplanation / Answer
With reference to the article published on the geological mechanism of continental rifting, I would like to provide the reasons as to why the statements made by the geologists of the University of Arizona were misleading and irrelevant. There is hardly any doubt among the geologists around the world that the Earth's crust is made up of plates which are moving due to the natural forces of tectonism originating below the crust. This hypothesis of plate movement and tectonism is very well known as the Plate Tectonic Theory. The reasoning provided by Dr. David Sarlow, as reported from Tucson, Arizona, is not scientifically sound as he attempts to explain the past drifting of continental plates through breaking of emotional bonds. The actual reason why plates have been moving and drifting apart in the geological past is due to the influence of a heat source in the mantle on a relatively cold lithosphere. The drifting mechanism of continents since the breakup of the supercontinent Pangea has been documented by different researchers over the past few decades. Studies by Morgan (1972), Ziegler (1992), Pavoni (1993), Bercovici (2003), Trubitsyn (2003) have shown that the tensional regimes in the lithosphere, i.e. the uppermost part of the Earth's crust, were generated due to heat flows from the warmer asthenosphere, i.e. the upper mantle, to the colder lithospheric crust. The convectively-driven tensions in the continental lithosphere led to the splitting of the supercontinent Pangea which clearly suggest the role of mantle-derived magmatic heat in the cycles of continental rifting.
References:
Bercovici, D. (2003). The generation of plate tectonics from mantle convection. Earth and Planetary Science Letters, 205(3-4), 107-121.
Morgan, W. J. (1972). Deep mantle convection plumes and plate motions. AAPG bulletin, 56(2), 203-213.
Pavoni, N. (1993). Pattern of mantle convection and Pangaea break-up, as revealed by the evolution of the African plate. Journal of the Geological Society, 150(5), 953-964.
Trubitsyn, V. P., Mooney, W. D., & Abbott, D. H. (2003). Cold cratonic roots and thermal blankets: how continents affect mantle convection. International Geology Review, 45(6), 479-496.
Ziegler, P. A. (1992). Plate tectonics, plate moving mechanisms and rifting. Tectonophysics, 215(1-2), 9-34.