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PROOF Meteorite SMASHED into Earth!! Decimated Half of Life!
Meteorite impact caused global darkness and cold
Palaeoclimatologists at Utrecht University, the VU University Amsterdam and the Royal Netherlands Institute for Sea Research (NIOZ) have found the first concrete evidence for global cooling caused by a meteorite impact some 66 million years ago. Their findings were published on 12 May 2014 in the leading Proceedings of the National Academy of Sciences journal.
Some 66 million years ago, a huge meteorite impact in the area of present-day Mexico caused the extinction of approximately half of all the plant and animal species on Earth. This meant not only the end of the dinosaur era, but also of the Cretaceous period. The Chicxulub impact, named after the village now located at the centre of the now-buried impact crater, marked the start of the Palaeogene era and caused a global drop in temperature lasting several decades.
Blocking the sun
The impact ejected huge quantities of dust and aerosols into the atmosphere, temporarily blocking the sunlight. This caused a rapid global drop in temperature, commonly referred to as ‘impact winter’. No concrete evidence of an impact winter had previously been found, but PhD student Johan Vellekoop (Utrecht University) found it in rock outcrops in Texas.
Right spot
Together with his colleagues, he discovered marine sediments in these outcrops. These sediments were laid down at the time of the meteorite impact. “The layer of sand and shells we found was deposited by tsunamis caused by the meteorite impact”, says Vellekoop. “In the rocks just above that layer we measured high concentrations of iridium, a mineral originating from the meteorite itself. That’s how we knew for sure we were looking at the right layers.”
By measuring certain lipids in single-celled organisms preserved in these rocks, the scientists could determine the seawater temperature at the time. Their reconstruction shows that the seawater temperature dropped at least 7°C immediately after the impact. “And that’s only a minimum estimate; it was probably much more”, says Vellekoop. “Storms following the tsunami completely stirred the sediments up.”
First concrete evidence
These findings are the first concrete evidence of an impact winter following the Chicxulub impact. This period of cold and darkness probably lasted several decades and must have been one of the main causes of the mass extinctions at the end of the Cretaceous.
Publication
‘Rapid short-term cooling following the Chicxulub impact at the Cretaceous-Paleogene boundary’, Johan Vellekoop (UU), Appy Sluijs (UU), Jan Smit (VU), Stefan Schouten (UU/NIOZ), Johan W.H. Weijers (UU), Jaap S. Sinninghe Damsté (UU/NIOZ) and Henk Brinkhuis (UU/NIOZ), published in the Proceedings of the National Academy of Sciences of 12 May 2014.
This research was funded by the Netherlands Organisation for Scientific Research (NWO).
Decimated means “one in ten”.
Pearls to swine on here mate.