Post by DannyRock on Feb 4, 2006 13:17:12 GMT -5
I just love it when the professional scientific community flips out over things like this. 
Experts clash over demise of the dinosaur
By Roger Highfield, Science Editor
(Filed: 02/02/2006)
The giant impact that shook the Earth 65 million years ago is still sending out shock waves, triggering a scientific feud over whether the event really killed off the dinosaurs.
Efforts to identify what wiped out the great creatures have been confused by evidence of massive volcanic activity in India at the same time, and a fossil record that suggests the dinosaurs disappeared gradually as the Earth's climate and geology changed over millions of years.
Now a bitter row has broken out on CCNet, a scholarly electronic network, over a paper by Peter Schulte of the Universität Erlangen-Nürnberg and colleagues in the journal Sedimentary Geology: they conclude that two cores drilled in Brazos, Texas, provide new support for the much-loved disaster movie scenario.
With Robert Speijer, Hartmut Mai and Agnes Kontny, Mr Schulte concludes that the evidence is "unequivocal" that debris and "ejecta" sent out by the impact coincides with the timing of the mass extinction.
Their work is the latest to back a remarkable hypothesis proposed in 1980 by the American father-and-son team Profs Luis and Walter Alvarez, who came to a cataclysmic conclusion after studying a thin layer of dirty sulphurous clay in Gubbio, Italy.
This clay marked what scientists call the K-T boundary, the junction between rocks in which the fossils of dinosaurs are found, and those above, in which dinosaur bones have been replaced by more modern creatures.
From the chemistry of the clay, the Alvarezes deduced that there had been a giant impact 65 million years ago, now called the Chicxulub impact.
The new paper, says the German team, "provides no evidence that Chicxulub predated the K-P (K-T) boundary and allows for unequivocal positioning of the K-P (K-T) boundary at the event deposit".
Not so, say detractors on CCNet. Prof Gerta Keller of Princeton University accused the team of "ignoring scientific methods", making claims with "no basis in fact" and "circular reasoning" by assuming a K-T age for the Chicxulub impact when this age is in doubt and predates the mass extinction.
Another detractor, from Utrecht University, denounced their "firm conclusions claiming 'unequivocal' certainty".
Though common wisdom among many scientists favours an asteroid strike ending the age of dinosaurs, one group of scientists remains doggedly undecided about this vision of apocalypse: dinosaur experts.
Angela Milner, of the Natural History Museum, London, said yesterday: "There is absolutely no consensus as to whether there was a sole cause and what it was. The feud does not involve people who work on dinosaurs, but sedimentologists and hard rock geologists."
The only thing that everyone can agree on is that the dinosaurs became extinct.
One problem is that the fossil record seems to show a gradual demise of some dinosaurs, and of many other species, well before the actual impact.
For example, an obscure group of molluscs, called rudists, studied by Peter Skelton at the Open University, slowly declined to only a few species by 66 million years ago - a million years before the asteroid hit.
And there are other mass extinctions that seem free of devastating impacts. The biggest happened about 250 million years ago, when 95 per cent of life was extinguished. Vast flood basalts of exactly that age are found in Siberia.
Many Earth scientists have come up with a different scenario for the demise of the dinosaurs, blaming it on volcanic forces.
The issue matters to more than just academics. The demise of the dinosaurs is of enduring interest to the public. And the world looks for lessons from the past about the effects of global climate change or asteroids striking Earth.
www.telegraph.co.uk/news/main.jhtml?xml=/news/2006/02/02/wdino02.xml
Experts clash over demise of the dinosaur
By Roger Highfield, Science Editor
(Filed: 02/02/2006)
The giant impact that shook the Earth 65 million years ago is still sending out shock waves, triggering a scientific feud over whether the event really killed off the dinosaurs.
Efforts to identify what wiped out the great creatures have been confused by evidence of massive volcanic activity in India at the same time, and a fossil record that suggests the dinosaurs disappeared gradually as the Earth's climate and geology changed over millions of years.
Now a bitter row has broken out on CCNet, a scholarly electronic network, over a paper by Peter Schulte of the Universität Erlangen-Nürnberg and colleagues in the journal Sedimentary Geology: they conclude that two cores drilled in Brazos, Texas, provide new support for the much-loved disaster movie scenario.
With Robert Speijer, Hartmut Mai and Agnes Kontny, Mr Schulte concludes that the evidence is "unequivocal" that debris and "ejecta" sent out by the impact coincides with the timing of the mass extinction.
Their work is the latest to back a remarkable hypothesis proposed in 1980 by the American father-and-son team Profs Luis and Walter Alvarez, who came to a cataclysmic conclusion after studying a thin layer of dirty sulphurous clay in Gubbio, Italy.
This clay marked what scientists call the K-T boundary, the junction between rocks in which the fossils of dinosaurs are found, and those above, in which dinosaur bones have been replaced by more modern creatures.
From the chemistry of the clay, the Alvarezes deduced that there had been a giant impact 65 million years ago, now called the Chicxulub impact.
The new paper, says the German team, "provides no evidence that Chicxulub predated the K-P (K-T) boundary and allows for unequivocal positioning of the K-P (K-T) boundary at the event deposit".
Not so, say detractors on CCNet. Prof Gerta Keller of Princeton University accused the team of "ignoring scientific methods", making claims with "no basis in fact" and "circular reasoning" by assuming a K-T age for the Chicxulub impact when this age is in doubt and predates the mass extinction.
Another detractor, from Utrecht University, denounced their "firm conclusions claiming 'unequivocal' certainty".
Though common wisdom among many scientists favours an asteroid strike ending the age of dinosaurs, one group of scientists remains doggedly undecided about this vision of apocalypse: dinosaur experts.
Angela Milner, of the Natural History Museum, London, said yesterday: "There is absolutely no consensus as to whether there was a sole cause and what it was. The feud does not involve people who work on dinosaurs, but sedimentologists and hard rock geologists."
The only thing that everyone can agree on is that the dinosaurs became extinct.
One problem is that the fossil record seems to show a gradual demise of some dinosaurs, and of many other species, well before the actual impact.
For example, an obscure group of molluscs, called rudists, studied by Peter Skelton at the Open University, slowly declined to only a few species by 66 million years ago - a million years before the asteroid hit.
And there are other mass extinctions that seem free of devastating impacts. The biggest happened about 250 million years ago, when 95 per cent of life was extinguished. Vast flood basalts of exactly that age are found in Siberia.
Many Earth scientists have come up with a different scenario for the demise of the dinosaurs, blaming it on volcanic forces.
The issue matters to more than just academics. The demise of the dinosaurs is of enduring interest to the public. And the world looks for lessons from the past about the effects of global climate change or asteroids striking Earth.
www.telegraph.co.uk/news/main.jhtml?xml=/news/2006/02/02/wdino02.xml