Asteroid impact 66 million years ago released aerosols and dust into Earth’s upper atmosphere that blocked the sun and killed the dinosaurs, study reveals
- Previous work suggests the black carbon that filled the air after an asteroid hit the Earth 66 million years ago was released by massive wildfires
- Now, researchers found evidence it was released from the impact itself
- Sediments from the Chicxulub crater site show a group of hydrocarbons
- These were formed from intense heat and released aerosols and dust into the air
New evidence discovered from the Chicxulub crater suggests the black carbon that filled the atmosphere after an asteroid struck Earth 66 million years ago was caused by the impact and not massive wildfires as previously suspected.
Researchers analyzed sediments from the crater, which is located in what is now the Yucatan Peninsula, and nearby ocean sites to determine the source of the soot that blocked the sun.
The team found a group of hydrocarbons that were heated rapidly during the event that released sulfate aerosols and dust into the atmosphere – sparking the ‘impact winter’ that led to the mass extinction.
The findings do support the previous theory of wildfires, but suggests the massive blazes were delayed and had less of an influence on killing 76 percent of life on Earth.
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New evidence discovered from the Chicxulub crater suggests the black carbon that filled the atmosphere after an asteroid struck Earth 66 million years ago was caused by the impact and not massive wildfires as previously suspected
The asteroid smashed into a shallow sea in what is ow the Gulf of Mexico that led to the Cretaceous-Paleogene mass extinction, including the nonavian dinosaurs.
Evidence of the impact has been discovered all across the globe and in K–Pg boundary records, which are features of rocks that preserve information about the history of Earth.
Scientists have long speculated that when the asteroid hit, the event sparked massive wildfires that released intense soot into the atmosphere.
However, a team of researchers from the US, Australia and the UK have uncovered a new story at the crater site.
Researchers analyzed sediments from the crater, which is located in what is now the Yucatan Peninsula, and nearby ocean sites to determine the source of the black carbon that blocked the sun
‘We present a detailed record of molecular burn markers (polycyclic aromatic hydrocarbons [PAHs]) from the Chicxulub crater and in ocean sediments distant from the impact site,’ reads the study published in PNAS.
‘PAH features indicate rapid heating and a fossil carbon source and are consistent with sedimentary carbon ejected from the impact crater and dispersed by the atmosphere.’
‘Target rock-derived soot immediately contributed to global cooling and darkening that curtailed photosynthesis and caused widespread extinction.’
The team found a group of hydrocarbons that were heated rapidly during the event, resulting in the release sulfate aerosols and dust into the atmosphere. This sparked the ‘impact winter’ that led to the mass extinction, which wiped out the dinosaurs
The work involved analyzing sediment samples from within the Chicxulub crater and from other ocean sites near the crater.
In their analysis, the researchers focused on PAHs, which can provide evidence of a source of black carbon.
This led them to a fossil source that released the black carbon and not from burned material from wildfires.
They also found that the characteristics of the PAHs showed they came about due to rapid heating, which, the researchers note, was consistent with rocky material ejected from an impact crater.
The researchers also found small amounts of charcoal in the samples, indicating that some small amount of burned biomass had also made its way into the atmosphere.
KILLING OFF THE DINOSAURS: HOW A CITY-SIZED ASTEROID WIPED OUT 75 PER CENT OF ALL ANIMAL AND PLANT SPECIES
Around 65 million years ago non-avian dinosaurs were wiped out and more than half the world’s species were obliterated.
This mass extinction paved the way for the rise of mammals and the appearance of humans.
The Chicxulub asteroid is often cited as a potential cause of the Cretaceous-Paleogene extinction event.
The asteroid slammed into a shallow sea in what is now the Gulf of Mexico.
The collision released a huge dust and soot cloud that triggered global climate change, wiping out 75 per cent of all animal and plant species.
Researchers claim that the soot necessary for such a global catastrophe could only have come from a direct impact on rocks in shallow water around Mexico, which are especially rich in hydrocarbons.
Within 10 hours of the impact, a massive tsunami waved ripped through the Gulf coast, experts believe.
Around 65 million years ago non-avian dinosaurs were wiped out and more than half the world’s species were obliterated. The Chicxulub asteroid is often cited as a potential cause of the Cretaceous-Paleogene extinction event (stock image)
This caused earthquakes and landslides in areas as far as Argentina.
But while the waves and eruptions were The creatures living at the time were not just suffering from the waves – the heat was much worse.
While investigating the event researchers found small particles of rock and other debris that was shot into the air when the asteroid crashed.
Called spherules, these small particles covered the planet with a thick layer of soot.
Experts explain that losing the light from the sun caused a complete collapse in the aquatic system.
This is because the phytoplankton base of almost all aquatic food chains would have been eliminated.
It’s believed that the more than 180 million years of evolution that brought the world to the Cretaceous point was destroyed in less than the lifetime of a Tyrannosaurus rex, which is about 20 to 30 years.