EARTHSC 1G03 Lecture Notes - Lecture 2: Plate Tectonics, James Hutton, Oceanic Crust
4 Oct 2016
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Document Summary
The huttonian revolution founding of modern geology by james hutton: uniformitarianism means that past geological events can be explained by forces occurring today. The present is the key to the past. Contrast: catastrophism: gradual change could cumulatively account for most of what was known about the earth in the 18th century, earth is a dynamic planet whose surface is constantly changing and whose materials are constantly being (re)cycled. Alfred wegener proposed that continents drifted and had formed from one supercontinent called pangaea. this theory was met with strong resistance. Wegener"s hypothesis: modern continents move slowly over the globe and have formed from the break-up of pangaea over the last 200 million years. But there was no known mechanism to explain how continents plowed through the rigid oceanic crust. Occurrences of tills (deposits) and striations (scratches) at locations serve as indicators that a region was covered by a glacier in the past.
