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Report Sez Volcanic Gases Killed The Dinosaurs

http://www.nature.com/news/2007/071031/full/news.2007.205.html Gas may be to blame for extinction Contrarian theory argues against meteorite killing dinosaurs.

A worldwide burp of volcanic gases caused the mass extinction that wiped out dinosaurs and other creatures 65 million years ago, says research reported this week. Its the latest argument from a group that has been trying for some time to discredit the leading theory that a meteorite striking Mexico led to the mass die-offs.

The international team says that we should instead blame plumes of climate-altering gas given off by monumental lava flows that stretch hundreds of kilometres across India.

The Deccan Traps, as theyre called, have been suspected before of having some sort of global impact around the end of the Cretaceous period and the beginning of the Tertiary, known as the KT boundary. Earlier research had dated the main outburst of the lava flows as occurring within 800,000 years of the boundary. But the new analysis uses tiny plankton fossils, trapped between lava layers, to date the flow to the boundary itself.

This is the first time we can link the main phase of the Deccan Traps to the mass extinction, says team leader Gerta Keller, a palaeontologist at Princeton University in New Jersey. Keller and Thierry Adatte of the University of Neuchtel in Switzerland presented their research on 30 October in Denver, Colorado, at the annual meeting of the Geological Society of America.