Asteroid May Have Killed Dinosaurs Quicker Than Scientists Thoug - Spokane, North Idaho News & Weather KHQ.com

Asteroid May Have Killed Dinosaurs Quicker Than Scientists Thought

Posted: Updated:

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.

  • Most Popular StoriesMost Popular StoriesMore>>

  • BACK TO SCHOOL: See where your school ranks in performance

    BACK TO SCHOOL: See where your school ranks in performance

    Tuesday, August 26 2014 9:18 PM EDT2014-08-27 01:18:51 GMT
    SPOKANE, Wash. - Two schools in the Spokane area received top rankings based on a new assessment, according to the Washington Policy Center. The Washington State Board of Education released a new assessment of the quality of schools around the state Tuesday. The assessment ranked schools on an "A to F-" scale, with 14 percent of schools in in and around Spokane finishing with A's or B's.>>
    SPOKANE, Wash. - Two schools in the Spokane area received top rankings based on a new assessment, according to the Washington Policy Center. The Washington State Board of Education released a new assessment of the quality of schools around the state Tuesday. The assessment ranked schools on an "A to F-" scale, with 14 percent of schools in in and around Spokane finishing with A's or B's.>>
  • Throwback Thursday! Look At 'Sunshine Shelly' Through The Years!

    Throwback Thursday! Look At 'Sunshine Shelly' Through The Years!

    Thursday, March 20 2014 1:04 PM EDT2014-03-20 17:04:11 GMT
    KHQ.COM - It's throwback Thursday! Here is a slideshow we would like to share of Shelly Monahan through the years! For those of you who have been in Spokane for many years, and saw her through her "Sunshine Shelly" days, you will probably remember the Shelly from back in those days. Enjoy!>>
    KHQ.COM - It's throwback Thursday! Here is a slideshow we would like to share of Shelly Monahan through the years! For those of you who have been in Spokane for many years, and saw her through her "Sunshine Shelly" days, you will probably remember the Shelly from back in those days. Enjoy!>>
  • Sheriff's Office seeks help finding missing teens

    Sheriff's Office seeks help finding missing teens

    Wednesday, August 27 2014 1:44 AM EDT2014-08-27 05:44:30 GMT
    SPOKANE, Wash. - The Spokane County Sheriff's Office took to Facebook asking for help finding three missing juveniles in the Inland Northwest.The three children were reported missing with the Spokane County Sheriff's Office and The National Center For Missing and Exploited Children. Their cases are not believed to be related.>>
    SPOKANE, Wash. - The Spokane County Sheriff's Office took to Facebook asking for help finding three missing juveniles in the Inland Northwest.The three children were reported missing with the Spokane County Sheriff's Office and The National Center For Missing and Exploited Children. Their cases are not believed to be related.>>
  • National NewsMore>>

  • VA: No proof delays in veteran care caused hospital deaths

    VA: No proof delays in veteran care caused hospital deaths

    Tuesday, August 26 2014 9:11 PM EDT2014-08-27 01:11:37 GMT
    KHQ.COM- The Department of Veterans Affairs says there's no proof that delays in care caused any deaths at the VA hospital in Phoenix, Ariz.Revelations that as many as 40 veterans died while awaiting care rocked the agency this past spring, bringing to light scheduling problems and allegations of misconduct at other hospitals as well.NBC News obtained a draft report from the VA's Office of Inspector General Tuesday. The draft report says while investigators found substantial delays in care an...>>
    KHQ.COM- The Department of Veterans Affairs says there's no proof that delays in care caused any deaths at the VA hospital in Phoenix, Ariz.Revelations that as many as 40 veterans died while awaiting care rocked the agency this past spring, bringing to light scheduling problems and allegations of misconduct at other hospitals as well.NBC News obtained a draft report from the VA's Office of Inspector General Tuesday. The draft report says while investigators found substantial delays in care an...>>
  • UPDATE: Sergeant who shot herself at Fort Lee dies

    UPDATE: Sergeant who shot herself at Fort Lee dies

    Monday, August 25 2014 6:58 PM EDT2014-08-25 22:58:27 GMT
    Police officer patrols the entrance of Fort Lee in VirginiaPolice officer patrols the entrance of Fort Lee in Virginia
    FORT LEE, Va. (AP) - A commanding general at a Virginia Army base says an enraged soldier with a gun barricaded herself in an office, then shot herself in the head as officials tried to negotiate with her.>>
    FORT LEE, Va. (AP) - A commanding general at a Virginia Army base says an enraged soldier with a gun barricaded herself in an office, then shot herself in the head as officials tried to negotiate with her. Maj. Gen. Stephen R. Lyons says the soldier went on a rampage, throwing objects. >>
  • Ice bucket challenge goes awry, firefighters hurt

    Ice bucket challenge goes awry, firefighters hurt

    Friday, August 22 2014 4:50 PM EDT2014-08-22 20:50:01 GMT
    CAMPBELLSVILLE, Ky. - A charity stunt that has grown into a social media phenomenon went terribly wrong for four Kentucky firefighters who were injured when a fire truck's ladder got too close to a power line after they dumped water on college students who were taking part in an "ice bucket challenge.">>
    CAMPBELLSVILLE, Ky. - A charity stunt that has grown into a social media phenomenon went terribly wrong for four Kentucky firefighters who were injured when a fire truck's ladder got too close to a power line after they dumped water on college students who were taking part in an "ice bucket challenge.">>