Their last beautiful day: It was spring when the dinosaurs died, European scientists estimate for the first time

by

It was spring and the flowers were blooming when the end of their season came dinosaurs. This is the romantic and at the same time sad conclusion of a new European scientific study, which for the first time makes an estimate for the specific time of year that fell to Earth, about 66 million years ago, the big asteroid that led to the disappearance of almost all then sovereign of the planet.

The researchers from the Swedenτη Francethe Netherlandsthe Belgium and Britain, led by Dr. Melanie During of the Swedish University of Uppsala, published in the journal Nature, estimate that the impact of the asteroid Chicxulub in the Yucatan Peninsula of present-day Mexico occurred when it was in the northern hemisphere. The catastrophic event is estimated to have caused a mass extinction of species, about 76% or three quarters of all living on Earth. Among the victims were non-flying dinosaurs, pterosaurs, ammonites and most marine reptiles, while mammals (for which the way was now open for domination), birds, crocodiles and turtles survived.

To date the impact determination had focused on the chronological accuracy of the event with deviations of the scale of a few thousand years, but the time of year was unknown. The researchers studied for the first time fish remains who had died en masse that day and were found in North Dakota, USA, analyzing – with the help of high-resolution X-ray tomography at the European Co-ordinator (ESRF) – the growth patterns imprinted on their fossilized bones. Combined with the analysis of data on carbon isotopes in fish bones, the “verdict” was that the catastrophe came in the spring.

Among other things, the collision of the great meteorite caused huge waves in the seas, lakes and rivers, burying many fish alive. The fish had fragments from the impact in their gills, but not lower in their digestive system, which is an indication that their death was almost instantaneous and occurred less than an hour after the impact.

The fall of the asteroid in the spring – if confirmed – would coincide with a particularly sensitive stage for many species that reproduced and developed at that time of year, which would contribute to the subsequent mass extinction. On the other hand, the species of the southern hemisphere, where there would be autumn then, then seem to have recovered at twice the speed of those of the northern hemisphere, according to the researchers.

Follow Skai.gr on Google News
and be the first to know all the news

You May Also Like

Recommended for you