During the springtime, an asteroid killed nearly all dinosaurs. An international team of scientists from the Vrije Universiteit (VU) Amsterdam (The Netherlands), Uppsala University (Sweden), Vrije Universiteit Brussel (Belgium) and the European Synchrotron have determined when the meteorite crashed into the Earth. Their results are in the journal Nature.
The demise of dinosaurs and the end of the Cretaceous period were marked by a meteorite that crashed into the Earth 66 million years ago. The mass extinction of non-avian dinosaurs, pterosaurs, ammonites, and most marine reptiles was one of the most complete mass extinctions in the history of life.
A team of scientists from the Vrije Universiteit, Uppsala University, and the ESRF have shed light on the circumstances surrounding the extinction of different groups. The answers came from the bones of fishes that died.
The waves in water bodies were caused by the impact of the meteorite. The waves moved enormous volumes of silt that engulfed fish and buried them alive, while impact spherules rained down from the sky, less than an hour after impact. The event deposit of Tanis in North Dakota has preserved a fossils that include paddlefishes and sturgeons, which were direct casualties of the event.
The bones of the fossil fishes were not altered by the elements. It was obvious to Melanie During that we needed to analyze the bones to get valuable information about the moment of the impact.
A partial fish specimen and sections of the bones were used to carry out high-resolution X-ray tomography at the ESRF.
The facility has developed expertise in paleontology over the last two decades, thanks to the data that the ESRF provides.
Senior author Jeroen van der Lubbe of the VU in Amsterdam states that the retrieved growth rings captured the life histories of the fishes and recorded the season in which the catastrophic extinction occurred.
The distribution, shapes, and sizes of the bone cells can be seen in the X-ray scans. Dennis Voeten, a researcher at Uppsala University, says that the growth of both cell density and volumes stopped in the spring.
The annual feeding pattern of a fish was revealed by the analysis of carbon isotope analysis. The availability of zooplankton peaked in the summer. The growth record of this unfortunate paddlefish shows that the feeding season had not yet ended.
It was spring in the Northern Hemisphere when the reproduction cycles of organisms were stopped. Many organisms were preparing for winter in the Southern Hemisphere. It is well known that organisms who were exposed died immediately. The results will help to uncover why most of the dinosaurs died out while birds and early mammals were able to survive.
More information: Melanie During, The Mesozoic terminated in boreal spring, Nature (2022). DOI: 10.1038/s41586-022-04446-1. www.nature.com/articles/s41586-022-04446-1 Journal information: Nature Citation: The reign of the dinosaurs ended in spring (2022, February 23) retrieved 23 February 2022 from https://phys.org/news/2022-02-dinosaurs.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
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