Asteroid delivered "decisive blow" to the dinosaurs..explosion in Mexico 66 million years ago coincided "precisely" with the prehistoric reptiles' demise

http://www.theaustralian.com.au/higher-education/asteroid-delivered-decisive-blow-to-the-dinosaurs-study/story-e6frgcjx-1226572879822

AN asteroid almost certainly put the nail in the dinosaurs’ coffin, according to researchers who have found that a colossal explosion in Mexico 66 million years ago coincided “precisely” with the prehistoric reptiles’ demise.

New dating techniques place the extinction of terrestrial dinosaurs and the Chicxulub asteroid impact within a mere 32,000 years of each other, far less than the previous estimates of up to 300,000 years.

The finding, published today in the journal Science, all but settles a decades-long dispute over whether an asteroid or volcanoes killed off the dinosaurs.

In 2010 an international team of experts concluded that the extinction had been triggered by the Chicxulub meteor, which measured at least 10 kilometres across and left a 180 kilometre crater in the Yucatan peninsula.

But estimates of the impact’s date have varied from 300,000 years before the dinosaurs’ extinction to 250,000 years afterwards.

The new study combined earlier dating techniques to show that the age of the two events was “indistinguishable from each other”, according to Heiko Pälike of the University of Bremen in Germany.

“The Chicxulub impact delivered a final coup de grâce to ecosystems, shifting the planet permanently into a new state,” Professor Pälikesaid.

Team leader Paul Renne, of the University of California Berkeley, said the Chicxulub impact had delivered a “decisive blow” to the ecosystems of the late Cretaceous period.

But these ecosystems, long accustomed to a “hothouse” climate, were already under “critical stress” from a million years of climate instability, including six abrupt drops of up to 8 degrees Celsius in average global temperatures.

Professor Renne said the explosion had “pushed the global ecosystems across a threshold”. While the earth’s carbon cycle had recovered in as little as 5000 years, this was enough to cause the permanent disappearance of terrestrial dinosaurs.

But the finding doesn’t put volcanoes in the clear, with a series of eruptions near Mumbai in modern-day India thought likely to have triggered the “cold snaps” that had brought dinosaurs to the tipping point.

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they are certain now..”precisely” coincided..the science is “settled” eh?

“The finding, published today in the journal Science, all but settles a decades-long dispute over whether an asteroid or volcanoes killed off the dinosaurs.”

as long as they are as confident as they were with “piltdown man”

401

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~ by seeker401 on February 12, 2013.