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Geology and Continental Drift

Alfred Wegener and Continental Drift

During the past century, considerable advances have been made in the field of geology. The discovery of plate tectonics has provided researchers with a unifying theory that explains many fundamental earth processes. Of the various hypotheses that led to plate tectonic theory, the most important was proposed by Alfred Wegener. Wegener's ideas on continental drift were supported by much evidence. However, perhaps because of its overwhelming implications, the theory was met with considerable resistance. Only in recent decades has scientific investigation collected sufficient evidence to definitively establish the validity of the continental drift hypothesis.

The theory of plate tectonics describes a lithosphere consisting of approximately the Earth's outer 100 kilometers. This layer comprises the uppermost mantle and all of the crust. Moreover, the lithosphere is broken up into several rigid plates. These include seven major structural plates and roughly twenty adjoining smaller plates (2:172-187). These rigid structures act as distinct mechanical units. They slide over a partially molten, plastic mantle zone known as the asthenosphere. According to the relative motions of adjacent plates, three different types of plate boundaries have been defined. These include the following: (1) divergent boundaries; (2) transform faults; and (3) boundaries of convergence (6:498-500). For one, divergent boundaries occur where plates are separating; second, transform faults exist where plates are sliding past each other. Third, boundaries of convergence generally involve one plate overriding another. The overridden plate is subducted back into the mantle where it is resorbed (6:498-500).

Geologists now believe that some 180-250 million years ago, at the close of the Paleozoic, the Earth's continents were joined together into a single supercontinent (4:16-17). This land mass--which ...

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Geology and Continental Drift. (1969, December 31). In LotsofEssays.com. Retrieved 11:29, March 28, 2024, from https://www.lotsofessays.com/viewpaper/1681233.html