Dinosaurs wiped out by asteroid impact that turned earth into a 'hellish' place
The dinosaurs were wiped out by an asteroid that struck the earth with the force of a billion Hiroshimas, according to leading scientists.
By Richard Alleyne, Science Correspondent
Published: 7:00PM GMT 04 Mar 2010
The asteroid, the size of the Isle of Wight, slammed into the Yucatan peninsula in Mexico at 20 times the speed of a bullet causing earthquakes, landslides, tsunamis and wildfires.
The destruction, 65 million years ago, was so great it left most of the world a wasteland, shrouded in dust, perpetually cold and virtually devoid of all life and vegetation.
The dinosaurs, which had ruled for 160 million years, were wiped out in a matter of days. Large marine reptiles, like the mosasaurs and the plesiosaurs, the flying reptiles known as pterosaurs, giant snail-like ammonites and many species of marine plankton, were also were also obliterated. Bird species also suffered losses but survived.
Some mammals survived, however, ultimately setting the stage for the rise of human beings.
The conclusion by a panel of 41 international scientists, that it was an asteroid that caused the disappearance of the dinosaurs, has come in a bid to end decades of speculation.
The panel, which reported in the journal Science, were set up in order to end debate over what caused the massed extinction at the end of the Cretaceous Period.
In particular, it wanted to dispel competing theories that it was caused by volcano eruption or climate change.
"Combining all available data from different science disciplines led us to conclude that a large asteroid impact 65 million years ago in modern-day Mexico was the major cause of the mass extinctions," said Professor Peter Schulte, at the University of Erlangen in Germany and lead author of the review paper.
Dr Joanna Morgan, co-author of the review from the Department of Earth Science and Engineering at Imperial College London, said: "We now have great confidence that an asteroid was the cause of the extinction.
"This triggered large-scale fires, earthquakes measuring more than 10 on the Richter scale, and continental landslides, which created tsunamis.
"However, the final nail in the coffin for the dinosaurs happened when blasted material was ejected at high velocity into the atmosphere.
"This shrouded the planet in darkness and caused a global winter, killing off many species that couldn't adapt to this hellish environment."
The key piece of proof was the discovery of a band of iridium – a metal rare on earth but common in meteorites – dating to the end of the Cretaceous Period that suggested the big space rock had smashed into the earth and blasted its remains around the globe.
On top of this, the fossil records clearly shows a mass extinction across the planet at about 65.5 million years ago.
Scientists have previously argued about the extinction could be caused by volcanic activity in India, where there were a series of super volcanic eruptions that lasted approximately 1.5 million years.
These eruptions spewed enough lava across the Deccan Traps in India, an area stretching from Mumbai almost to the Himalayas, which is thought to have caused a cooling of the atmosphere and acid rain on a global scale.
In the new study, scientists, including ones of University of Cambridge, Imperial College London and Open University, analysed the work of palaeontologists, geochemists, climate modellers, geophysicists and sedimentologists who have been collecting evidence about the extinction over the last 20 years.
Dr Gareth Collins, Natural Environment Research Council Fellow and another co-author from the Department of Earth Science and Engineering at Imperial College London, said: "The explosion of hot rock and gas would have looked like a huge ball of fire on the horizon, grilling any living creature in the immediate vicinity that couldn't find shelter.
"Ironically, while this hellish day signalled the end of the 160 million year reign of the dinosaurs, it turned out to be a great day for mammals, who had lived in the shadow of the dinosaurs prior to this event.
"The extinction was a pivotal moment in Earth's history, which ultimately paved the way for humans to become the dominant species on Earth."
as a geologist i have always been interested in this question, and i have always suspected that the extinction event had as much to do with deccan volcanism and ocean annoxia as it did with the yucatan impact; i.e. i believed the asteroid was the final nail in the coffin of an already highly 'distressed' group.
I was wrong, mea-culpa, the scientific consensus is that it was the asteroid impact that was the primary cause of the extinction.
Furunculus Maneuver: Adopt a highly logical position on a controversial subject where you cannot disagree with the merits of the proposal, only disagree with an opinion based on fundamental values. - Beskar
Re: it really was the asteroid wot killed the dinosaurs!
The asteroid, the size of the Isle of Wight, slammed into the Yucatan peninsula in Mexico at 20 times the speed of a bullet
Whoa.
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Re: it really was the asteroid wot killed the dinosaurs!
Originally Posted by Sarmatian
I'm not an expert in biology or geology, but wasn't that theory already accepted by most scientists?
nah, there were multiple possible causes, and really they all had an effect, it was just a question of whether any one of them could be singled out as having a definitive 'impact' on the extinction event: http://en.wikipedia.org/wiki/Cretace...tinction_event
Deccan Traps volcanism was truly staggering, involving the surface release of around two million CUBIC kilometres of flood basalt over the course of a million or so years: http://en.wikipedia.org/wiki/Deccan_Traps
Not an unreasonable culprit given that the Siberian Traps event was strongly implicated in the Permo-Triassic extinction event 200 million years earlier: http://en.wikipedia.org/wiki/Siberian_Traps
Furunculus Maneuver: Adopt a highly logical position on a controversial subject where you cannot disagree with the merits of the proposal, only disagree with an opinion based on fundamental values. - Beskar
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it really was the asteroid wot killed the dinosaurs!
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