Plate Tectonics

Global geological phenomena have been described by theory of plate tectonics. Plate tectonism assumes the movement of plates at earth’s crust influenced by convection of magma inside the mantle. Tectonic plates are the segments of lithosphere which move and change in shape and size continuously (Condie, 1997). Lithosphere, the rigid and brittle outermost mechanical layer of the earth, extends up to 100 km beneath the surface (California State University, n.d.) and deformation and faults are resulted from the movements of rigid lithospheric plates. Faulted rocks in El Salvador, folded rocks along the San Andreas and folded and faulted rocks in the Himalayan region are few examples of deformed rocks (California State University, n.d.).

Activities of tectonic plates, cooling mechanism of earth’s mantle and mantle convection illustrate plate tectonics theory. Niu (2014) assumes the consumption of tectonic plates into the earth’s interior through subduction zones. Continental drift, sea floor spreading and mantle plumes are other geologic phenomena related with plate tectonics. Niu (2014) described the mantle plume as cooling mechanism of the earth’s core.

Water, its highest heat capacity and role of ocean as a sink to cool the mantle has been identified as one of the driving forces of plate tectonics (Niu, 2014). In contrast, size, circumference and ridge length of a plate has fewer influences on plate motion (Forsyth and Uyeda, 1975 cited in Niu, 2014). Movement of tectonic plates has three principle mechanisms: divergent, convergent and transform. Plates move apart from each other at divergent plate boundaries, plates crash with each other along convergent plate boundaries and plates slide with each other along a transform plate boundary (Kean University, n.d.).

References
California State University (n.d.) Natural Disasters [Online] Available at http://www.csus.edu [Accessed on 20 may 2015]
Condie, K.C. (1997) Plate Tectonics and Crustal Evolution [Online] Available at http://www.bayanbox.ir/view [Accessed on 15 May 2015].

Forsyth, D. and Uyeda, D. (1975) On the Relative Importance of the Driving Forces of Plate Motion- Geophysics Journal International, Vol 43, pp. 163-200.

Kean University (n.d.) Plate Tectonics [Online] Available at http://www.kean.edu [Accessed on 21 may 2015].

Niu, Y. (2014) Geologic Understanding of Plate Tectonics: Basic Concepts, Illustrations, Examples and New Perspectives. Global Tectonics and Metallogeny, Vol 10 (1), pp. 23-46.

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