The diversity of dinosaurs that dominated the planet’s surface for hundreds of millions of years has, finally, a definitive conclusion: about 66 million years ago the impact of an asteroid about 11 kilometers wide in the Yucatan Peninsula in the present Mexico precipitated the extinction of 75% of life on Earth, including all non-avian dinosaurs. This theory has just been described as “solved”, thanks to the fact that an international team of researchers working on the investigation of materials in the Chicxulub collision crater of the Yucatan peninsula, has concluded that the chemical characteristics of the meteorite dust in the rock are undoubtedly associated, after comparing it with the geological limits of the dinosaur extinction event, to this tragic end.
According to experts, the thin layer of dust that was deposited on the earth’s crust 66 million years ago was due to a collision event in this same place. They are connected.
Finding a distinctive layer of rocks enriched in iridium and other heavy elements in many parts of the planet, the idea began to take shape that an asteroid or comet had caused the deaths of non-avian dinosaurs. Iridium is much more common in small space objects than it is in the Earth’s crust, because much of it has sunk into the Earth’s core . And the time of the formation of this layer coincided with the disappearance of the dinosaurs, which led to the search for a crater. It’s Chicxulub.
This suggested that impact-related particles, including vaporized elements from the asteroid itself, spread around the world rapidly after the impact. They blocked the light emitted by the sun and, in the process, triggered a global winter. And, although many already closed the matter, others questioned whether we could really be sure that both the crater and the iridium layer had to do with the event of devastating consequences.
The authors of the new study believe they have finally “come full circle” on the mystery, finding asteroid dust in the Chicxulub impact crater that matches particles embedded in the 66-million-year-old layer discovered in the 1980s.
“Now we are at the level of agreement that geologically it does not happen without causality,” explain the authors of the study published in the journal Science Advances. “It removes any doubt that the iridium anomaly in the geologic layer is not related to the Chicxulub crater.”
In fact, the scientists combined the results from four independent labs around the world to make sure everything was correct.
In addition to iridium, the crater section showed elevated levels of other elements associated with the asteroid material, according to experts. Its concentration and composition resembled measurements taken of the geological layer at 52 sites around the world, adding to the proof that the layer was created by the 11 km-wide asteroid 66 million years ago.
Dinosaurs ruled the Earth for more than 170 million years, and now we finally know how they disappeared.
Referencia: “Globally distributed iridium layer preserved within the Chicxulub impact structure” Science Advances (2021). advances.sciencemag.org/lookup … .1126/sciadv.abe3647
