The Cause of the Dinosaur Extinction Essay

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The Cause of the Dinosaur Extinction

The biggest mystery surrounding the dinosaur is how did they die? For over 130 million years dinosaurs ruled the earth. Then 65 million years ago, at the end of the Cretaceous period, they died out. Nobody can really say what actually eliminated the species, although everyone has their very own idea. Asteroid impact, atmospheric changes (hot to cold), catastrophic eruptions and astronomical events (supernovas etc.). Some have ventured that early mammal inhabitation slowly “pushed” the dinosaurs to extinction. The most favored theory in the scientific field is that of the meteor impact. As always though, knowing when is part of discovering how and why.

THE TIMING OF THINGS One problem
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By testing sediment and recording whether it was deposited under conditions of normal polarity and then measuring successive layers, we can build a time chart. By matching different charts from different areas with similar fossils, a more global correlation can be made. These techniques led to the discovery of the boundary between the two eras. A single thin layer of clay found within predominantly limestone rocks established this. By comparing the marine life found in, above, and below the clay, the marine life, like the dinosaurs, had been terribly affected by the extinction event. The percentage of life in the upper layers was dramatically lower than that in the lower. This was far more compelling than what was suggested by dinosaur’s fossils. Other samples of the clay were taken to laboratories to be analyzed. Part of the results showed a large concentration of platinum and iridium. These elements are very rare on the surface of the earth at the moment but they are present in meteoric dust that rains down from space at a known rate. That rate allowed for a measurement of how long it took for the clay to form. Surprisingly, the clay held almost 30 times more iridium than the limestone layers above and below the clay. Similar layers in other parts of the world gave the same results. The conclusion was that a giant meteorite hit the Earth 65 million years ago and had released a large