Asteroid may have killed dinosaurs quicker than scientists thought

CAPE CANAVERAL, Florida Fri Feb 8, 2013 4:56am EST

Image courtesy of NASA shows an artist's concept of a broken-up asteroid. Scientists think that a giant asteroid, which broke up long ago in the main asteroid belt between Mars and Jupiter, eventually made its way to Earth and led to the extinction of the dinosaurs. REUTERS/NASA/JPL-Caltech/Handout

Image courtesy of NASA shows an artist's concept of a broken-up asteroid. Scientists think that a giant asteroid, which broke up long ago in the main asteroid belt between Mars and Jupiter, eventually made its way to Earth and led to the extinction of the dinosaurs.

Credit: Reuters/NASA/JPL-Caltech/Handout

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CAPE CANAVERAL, Florida (Reuters) - Dinosaurs died off about 33,000 years after an asteroid hit the Earth, much sooner than scientists had believed, and the asteroid may not have been the sole cause of extinction, according to a study released Thursday.

Earth's climate may have been at a tipping point when a massive asteroid smashed into what is now Mexico's Yucatan Peninsula and triggered cooling temperatures that wiped out the dinosaurs, researchers said.

The time between the asteroid's arrival, marked by a 110-mile-(180-km-)wide crater near Chicxulub, Mexico, and the dinosaurs' demise was believed to be as long as 300,000 years.

The study, based on high-precision radiometric dating techniques, said the events occurred within 33,000 years of each other.

Other scientists had questioned whether dinosaurs died before the asteroid impact.

"Our work basically puts a nail in that coffin," geologist Paul Renne of the University of California Berkeley said.

The theory that the dinosaurs' extinction about 66 million years ago was linked to an asteroid impact was first proposed in 1980. The biggest piece of evidence was the so-called Chicxulub (pronounced "cheek'-she-loob") crater off the Yucatan coast in Mexico.

It is believed to have been formed by a six-mile-(9.6-km-) wide object that melted rock as it slammed into the ground, filling the atmosphere with debris that eventually rained down on the planet. Glassy spheres known as tektites, shocked quartz and a layer of iridium-rich dust are still found around the world today.

Renne and colleagues reanalyzed both the dinosaur extinction date and the crater formation event and found they occurred within a much tighter window in time than previously known. The study looked at tektites from Haiti, tied to the asteroid impact site, and volcanic ash from the Hell Creek Formation in Montana, a source of many dinosaur fossils.

NEW DATING TECHNIQUE

"The previous data that we had ... actually said that they (the tektites and the ash) were different in age, that they differed by about 180,000 years and that the extinction happened before the impact, which would totally preclude there being a causal relationship," said Renne, who studies ties between mass extinctions and volcanism.

He and colleagues were comparing a new technique to date geologic events when they realized there was a discrepancy in the timing - the so-called 'K-T boundary' - the geological span of time between the Cretaceous and Paleocene periods when the dinosaurs and most other life on Earth died out.

"I realized there was a lot of room for improvement. Even though many people had locked in their opinions that the impact and the extinctions were synchronous or not, they were basically ignoring the existing data," Renne said.

The study, published in Science, resolves existing uncertainty about the relative timing of the events, notes Heiko Pälike of the Center for Marine Environmental Sciences at the University of Bremen, Germany.

Renne, for one, does not believe the asteroid impact was the sole reason for the dinosaurs' demise. He says ecosystems already were in a state of deterioration due to a major volcanic eruption in India when the asteroid struck.

The asteroid strike "provided the coup-de-grace for the final extinctions," Renne said, adding that the theory was speculative, but backed by previous ties between mass extinction events and volcanic eruptions.

About 1 million years before the impact, Earth experienced six abrupt shifts in temperature of more than 2 degrees in continental mean annual temperatures, according to research cited by Renne and his co-authors.

The temperature swings include one shift of 6 to 8 degrees that happened about 100,000 years before the extinction.

"The brief cold snaps in the latest Cretaceous, though not necessarily of extraordinary magnitude, were particularly stressful to a global ecosystem that was well adapted to the long-lived preceding Cretaceous hothouse climate. The Chicxulub impact then provided a decisive blow to ecosystems," Renne and his co-authors wrote in Science.

(Editing by Tom Brown and Stacey Joyce)

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Comments (4)
morbas wrote:
The Dinosaur died million(s) of years before the Chicxulub event, no fossiles have been found in stratum dated up to or after the event. A deep global cooling impulse is located at the start of the Maastrichtian Stage, and Dinosaur species declined throughout that stage.

Feb 09, 2013 12:32pm EST  --  Report as abuse
BruceVoigt wrote:
About 13,000 years ago it is apparent that an area including Chicago and Northern Washington harbored man and the woolly mammoth and it is apparent that at about that time a mini ice age occurred.

Common sense tells me that although the mammoth was designed for cold climate it would not survive in today’s high arctic.
Common sense also tells me that about 13,000 years ago Chicago was much further north in relation to the Earths meandering axis.
Frozen mammoth found in the arctic still have food of the day in their stomach and that food is not capable of growing there.
So this is what happened;

About 13,000 years ago Earth took a dramatic tipping on its meandering magnetic axis that changed Earths exposure to both Sun and Moon. It was this that created our mini ice age.
You will find that about 13,000 years ago, on the other side of the world, England and area would be experiencing a tropical environment.
About 3,000 years later Earth flip flopping produced England’s mini ice age and through this time British Columbia was ice free.

There are violent forces at play. The forces of the Sun, Moon and Earth dance together giving us seasons, tides etc. The Sun recently has been stepping on toes as it glides through this dance sending our north magnetic pole whizzing away a thousand miles to wards Russia then coming home to dance around an 85km oval every 24hr.
This seemingly little dance is causing all kinds of hell for a species that thinks its the be and end all of the Universe. This Sun activity can muck around with slivers of Earth energy causing the Earth to tip, compasses to swing, radio reception, gps problems, tornado’s, tsunami, relocation of oceans and climate etc. (BUT)

The big kahuna Earths NUCLEUS is not PHASED by this UNTIL!
Our NINTH Planet third or fourth from the sun comes bar-ling around the Sun appearing to be heading right for us.

I Bruce Voigt claim that the recently discovered Asteroid 2002 AA 29 is really a Moon of (and yes I have named this Planet) OLD BRUCE.
OLD BRUCE orbits the Sun in close proximity to Earths orbit every 365 point something day’s and the Earth is slowly catching up or visa versa.
In approximately sixty five million years from now OLD BRUCE will be close enough to change (like a magnet) Earths Nucleus direction. At that very moment instant freezing takes place and because of no gravity any thing not attached drifts out into Earth orbit to be collected by the Moon. (Good real estate investment for an optimist).

These are the Three true Ice ages, one in coming two as Old Bruce eclipses Earth (the really big sleep) and three as Old Bruce again changes the Earths nucleus and nuclei direction.
So now after all that you now know what happened to DINO!
Bruce Voigt Science
PS -
The last location of the meandering north magnetic pole that I tracked down was a long way from home at 81.3 N 110.8W

Feb 09, 2013 2:29pm EST  --  Report as abuse
americanguy wrote:
More proof global warming is manure.
The earth is THAWING from the ice age and returning to normal from a disaster (it will take about 30 million years or more).
The poles were never frozen until the ice age. The oceans were 60 miles into land from where they are now. Volcanoes spewed huge amounts of pollution and CO2 and yet the earth did not cool, (strange isn’t it?.)
Teachers can feed lies to their kiddies about “global warming”, and forbid them to talk about the ice age, but the truth is there if anyone wants to study it.
“we don’t need no thought control…..” PF

Feb 09, 2013 4:09pm EST  --  Report as abuse
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