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Chinese scientists are closing in on determining the geological stratum record of the extinction events which resulted in dinosaurs disappearing completely 65 million years ago.

The research on the dividing line between Cretaceous and Tertiary periods, or the K/T Boundary, could provide important clues to the reasons for the extinction of dinosaurs, said leading scientist Sun Ge, of Jilin University.

Scientists from China, the United States, Russia, Germany and other countries chose a stratum section in Jiayin County, northeast China's Heilongjiang Province, and collected fossil samples hoping to find evidence of the sudden loss of life and possibly of a revival. 

Sun said the K/T Boundary, several centimeters thick, was regarded as the "time point" when the extinction occurred.

The Cretaceous period marked the end of the Mesozoic time during which dinosaurs ruled the planet while the Tertiary period was the beginning of the Cenozoic era when humans evolved.

Scientists have said the discovery of K/T boundaries in North America and other regions were accompanied by significant increases of the radioactive element iridium. One theory is that this could have been result of a meteor strike.

They've also discovered in Jiayin County dinosaur fossils from a time just prior to the sudden disappearance of the beats and evidence of flora which appeared immediately after.

They say the fossils discovered in Jiayin have a correlation with fossilized organisms found in K/T boundaries elsewhere. The Jiayin fossils also feature special characteristics in form and type.

The stratum environment in Jiayin is also superior to K/T boundaries in North America and Russia, according to the scientists.

The research program, initiated by Jilin University, is supported by the State Natural Science Fund Committee of China. The final results are expected to be released at the end of this year.

Experts say the results could be used as reference point to prevent a possible future cataclysmic event and to curb the effects of current environmental degradation.

(Xinhua News Agency July 12, 2006)