When an asteroid not only wiped out dinosaurs about 66 million years ago, it was early summer in the northern hemisphere. A team of researchers found this out on the basis of a very special site. The last great mass extinction in the history of the earth took place at a time of growth and reproduction for large parts of the animal and plant world. The knowledge suggests that flora and fauna in the northern hemisphere was worse affected than that in the southern hemisphere. In addition, a particularly large number of young animals would be affected at this time of the year. So one could speculate whether an impact just a few months earlier or later would have had drastically different consequences for the dinosaurs.
Telltale herringbones
The researchers working with Robert DePalma from the University of Manchester were able to date the asteroid impact in this way based on a site called Tanis in the US state of North Dakota. Thanks to extensive analyzes using various methods, the team had previously shown that it was the only known site with remains of plants and animals that had perished as a result of the asteroid impact. Now, based on detailed examinations of the remains, they were able to determine for themselves at what time of year this took place. Patterns in fish bones, for example, which show seasonal changes similar to annual rings in trees, have helped. The determined age of the youngest fish also confirmed the determined season in late spring and early summer, explain it.
The analysis adds another piece of the puzzle to our knowledge of the devastating asteroid impact 66 million years ago. In the meantime it has been proven that this was responsible for the mass extinction that, among other things, ushered in the age of mammals and thus of us humans. Other possible explanations had long been discussed. DePalma now thinks that the now possible seasonal dating of the impact is “directly applicable to our lives”. The fossils are a key to our understanding of how life reacted to such a global catastrophe and how it should react again. This means that you can plan better for tomorrow. Your study was published in the journal Nature.
(mho)
