Disappearance of the Lizards – Dino Theory: In Mexico, researchers found further evidence

Remnants of asteroid dust have been discovered in Chicxulub crater. This confirms the most likely theory of dinosaur extinction.

On the run: drawing of a tyrannosaurus.

Foto: Getty Images/Science Photo Libra

Since the 1980s, paleontologists have been discussing whether a large asteroid impact around 66 million years ago sealed the end of the dinosaur era. But there are always objections to this thesis. Another current claims that a series of volcanic eruptions were responsible for the extinction.

Now an international group of researchers has found something that should finally prove the asteroid thesis. Scientists from the University of Texas at Austin have been collecting drill samples in Chicxulub crater in the Gulf of Mexico since 2016. The almost 200-kilometer crater, discovered in 1991, is considered the site of the impact of the asteroid that is said to have killed the dinosaurs. In the study, which was published in the journal “Science Advances”, they report high iridium concentrations in the drill cores.

In 2019, US paleontologists described fossils of plants and fish, the death of which is directly related to the impact in the Gulf of Mexico.

This finding of the rare element is a hot trail. The founders of the asteroid thesis, Walter Alvarez and his father Luis Alvarez, discovered in 1980 a limestone layer with a high iridium content in the rock, which was formed at the end of the era of the dinosaurs. Iridium is rarely found on Earth, but on certain asteroids. Such a thing must have hit the earth, they concluded. The dust that was blown up darkened the sun and triggered a cold period. Plants perished, and so did the dinosaurs. So much for the – greatly simplified – theory that is supposed to explain the disappearance of the lizards at the end of the Cretaceous Period.

With the iridium finds in the impact crater, proponents of this theory now have another strong evidence, after the discovery of the crater itself 30 years ago. Geochemistry professor and head of studies Steven Goderis from Brussels even goes so far as to say that “the circle is finally coming full circle”. The massive occurrence of iridium in Chicxulub crater removes any doubt that there is a causal relationship between the asteroid impact and the high iridium content of many rocks from this period. There are also further indications: in 2019, US paleontologists described fossils of plants, fish and other animals, the death of which is directly related to the impact in the Gulf of Mexico.

Supporters of the volcano hypothesis argue that the Iridium anomaly could also be due to volcanic eruptions. They link the extinction of the dinosaurs to the high level of activity of the Deccan trap in India. The Dekkan-Trapp is one of the largest regions of volcanic origin in the world. However, the theory is extremely controversial. Among other things, because the iridium has isotope ratios that are unusual for volcanoes.

Published: 02/27/2021, 11:30 PM

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