"must not forget to mention the Himalayas and Mount Everest because this is the third example of plate movement
Millions of years ago India and an ancient ocean called the Tethys Ocean were sat on a tectonic plate. This plate was moving northwards towards Asia at a rate of 10 centimetres per year. The Tethys oceanic crust was being subducted under the Asian Continent. The ocean got progressively smaller until about 55 milion years ago when India 'hit' Asia. There was no more ocean left to lubricate the subduction and so the plates welled up to form the High Plateau of Tibet and the Himalayan Mountains. The continental crust under Tibet is over 70 kilometres thick. North of Katmandu, the capital of Nepal, is a deep gorge in the Himalayas. the rock here is made of schist and granite with contorted and folded layers of marine sediments which were deposited by the Tethys ocean over 60 million years ago."
Tuesday, May 11, 2010
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