Theories on Dinosaur Extinction

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Theories on Dinosaur Extinction

What killed the dinosaurs? Several theories have been brought up over time to answer this question. It has been of vast interest to many scientists how creatures the size of the dinosaurs could have been wiped out of existence.

Proposed Theories

Climate Change Theory

Some scientists propose that climate change was killing the dinosaurs before the famous asteroid struck. Fossil evidence shows that the average temperature had dropped from 25 degrees Celsius to 15 degrees Celsius and that the amount of annual rainfall had decreased. Fossil evidence also shows that more than half of the dinosaurs (many large plant-eating dinosaurs), crocodiles, and turtles of the time were gone before the asteroid struck in the Cretaceous period.

The Firestorm Theory

At one point it was thought that an impact from an asteroid combined with volcanic activity would have created mass numbers of firestorms with ground temperatures reaching 1000 degrees Celsius. It was thought that anything that was not destroyed directly from the fires would have died due to blocked sunlight as a result from the soot.

However, new studies have shown that rocks from the supposed time of impact contain little charcoal. In order for it to be possible for the massive firestorms to have occurred, charcoal would have had to have been present in the rocks. Without charcoal there is little likelihood that this theory is true.

Still, some debate that although some investigations claim to have not found charcoal in the rocks, they fail to report that they did find coal. These skeptics claim that coal is not easily distinguishable from charcoal and point out that it is possible that investigators missed signific...

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...edition. [updated 9 December 2003; retrieved 3 April 2004]. Available from http://64.4.26.250/cgi-bin/linkrd?_lang=EN&lah=b4d07bf5d8f3c8aa859357b57dc95a13&lat=1081128151&hm___action=http%3a%2f%2fnews%2ebbc%2eco%2euk%2f1%2fhi%2fsci%2ftech%2f3295539%2estm

“Scientists seek new clues to dinosaur demise.” Geographical v.73 i3, (2001): 10. In InfoTrac Onefile Plus [database online]. Cited 3 April 2004. Available from Ithaca College Libraries.

Stover, Dawn. “What Wiped the Earth Clean?” Popular Science V.264 i3, (2004): 56-59. In MasterFILE Select [database online]. Available from Ithaca College Libraries.

Holton, Woody. "The Ohio Indians and the Coming of the

American Revolution." The Journal of Southern History 7,

(1994): 453-478. In JSTOR [database online]. Cited 31

July 2001. Available from Duke University Libraries.

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