SCOTTISH scientists have revealed that a huge asteroid impact was the main reason that dinosaurs became extinct.
The Glasgow University team discovered that the date of the impact, which left a 110-mile wide crater in the Caribbean off the Yucatan coast of Mexico, was simultaneous with the disappearance of dinosaurs and many ocean creatures.
Although scientists in the 1980s first attributed the demise of the dinosaurs to asteroid impact, later research suggested volcanic eruptions or even climate change might have been an alternative reason why the species suddenly died out.
There was also confusion over whether the impact occurred before or after the extinction, characterised by the almost overnight disappearance from fossil records of land-based dinosaurs and ocean-dwelling creatures. Researchers at the Scottish Universities Environmental Research Centre in East Kilbride have concluded the date of impact and extinction are so close that it’s likely an asteroid, if not wholly responsible for the global extinction, dealt the “death blow” to the dinosaurs.
The new date for the impact of 66,038,000 years ago is the same as the date of the extinction.
A team led by Dr Darren Mark conducted analyses measuring the ratio of radioactive potassium in a sample of rock, to create a progressive timeline of events.
Dr Mark said: “This study allows us to piece together the sequence of Earth history”.
The Scottish team worked alongside researchers from the Berkeley Geochronology Centre (BGC), the University of California, and Vrije University in Amsterdam.
Paul Renne, BGC director said: “We have shown that these events are synchronous to within a gnat’s eyebrow, and therefore the impact clearly played a major role in extinctions.”