London, Nov 1 (PTI) The Chicxulub asteroid impact - thatwiped out the dinosaurs 66 million years ago - likely releasedclimate-altering sulphur and cooled the Earth far more thanoriginally thought, a study has found.
The research makes a more refined estimate of how muchsulphur and carbon dioxide gas were ejected into Earth'satmosphere from vaporised rocks immediately after theChicxulub event.
Scientists estimate more than three times as much sulfurmay have entered the air compared to what previous modelsassumed, implying the ensuing period of cool weather may havebeen colder than previously thought.
The study lends support to the hypothesis that the impactplayed a significant role in the Cretaceous-Paleogeneextinction event that eradicated nearly three-quarters ofEarth's plant and animal species, according to Joanna Morgan,from the Imperial College London in the UK.
"Many climate models can't currently capture all of theconsequences of the Chicxulub impact due to uncertainty in howmuch gas was initially released," Morgan said.
"We wanted to revisit this significant event and refineour collision model to better capture its immediate effects onthe atmosphere," she said.
The Chicxulub impact occurred 66 million years ago whenan asteroid approximately 12 kilometers wide slammed intoEarth. The collision took place near what is now the Yucatánpeninsula in the Gulf of Mexico.
The asteroid is often cited as a potential cause of theCretaceous-Paleogene extinction event, a mass extinction thaterased up to 75 per cent of all plant and animal species,including the dinosaurs.
The asteroid collision had global consequences because itthrew massive amounts of dust, sulfur and carbon dioxide intothe atmosphere.
The dust and sulfur formed a cloud that reflectedsunlight and dramatically reduced Earth's temperature.
The study, published in the journal Geophysical ResearchLetters, showed that the Earth's average surface airtemperature may have dropped by as much as 26 degrees Celsiusand that sub-freezing temperatures persisted for at leastthree years after the impact.
Scientists simulated the pressure of the shock wavescreated by the impact to estimate the amounts of gasesreleased in different impact scenarios.
They changed variables such as the angle of the impactand the composition of the vaporized rocks to reduce theuncertainty of their calculations.
The results show the impact likely released about 325gigatonnes of sulphur and 425 gigatonnes of carbon dioxideinto the atmosphere, more than 10 times global human emissionsof carbon dioxide in 2014.
Previous study that modelled Earth's climate after thecollision had assumed 100 gigatonnes of sulphur and 1,400gigatonnes of carbon dioxide were ejected as a result of theimpact. PTI MHN SARMHN.
This is unedited, unformatted feed from the Press Trust of India wire.