Scientists have revealed an amazing picture of the impact of the starving fall that destroyed the dinosaurs 66 million years ago.
Excavations in the North in the United States reveal fossils of fish and trees sprayed with fragments of rock and glass and fell from the sky.
The deposits also show evidence of being flooded with water – due to the huge tsunami produced by the effect.
The details were revealed in the PNAS magazine.
Robert DePalma of the University of Kansas and his colleagues say that the excavation site in an area of the name Tanis offers an incredible view of events that happened probably within minutes or hours after the Earth hit a huge asteroid.
When this 12 kilometer wide object hit what is now the Gulf of Mexico, it would have thrown billions of tonnes of melted rock and condensation in the air in all directions – and for thousands of miles.
In Tanis, the fossils record the time when this material fell back, like drops, everything fired a machine.
The fish were discovered with debris created by effect incorporated into their gills. They would have breathed the pieces that filled the water from their surroundings.
There are also particles held in amber, which are preserved remains of tree resin. And it is even possible to identify the remains left by these small tiny teapots – as these small glass rocks are technically called – when they enter the resin.
Geochemists were able to connect the material produced by the asteroid collapse directly to the Chicxulub effect site in the Gulf. They also dated the 65.76 million years, which is entirely in line with the chronology of the event developed from evidence gathered elsewhere in the world.
As the Tanis deposits were organized, the scientists were able to point out that a huge water wave had hit the area.
Although the effect had created a huge tsunami, it would take several hours to the 3,000 km travel wave of the Gulf to North Dakota, despite the likely presence of a sea crossing directly across North America.
Instead, researchers believe that local water can be displaced much more quickly by the seismic shock wave – equivalent to a 10 or 11 earthquake – which would have wrapped around the Earth. There is a kind of wave described as a check, which would have caught everything forward and was thrown into the thickness of specimens that are now recorded by the team.
"A mixture of freshwater fish, terrestrial vertebrates, trees, branches, logs, marine ammonites and other marine creatures have all been compacted in this layer by the wave," said DePalma.
"A tsunami would have taken at least 17 hours to reach the crater site, but seismic waves – and subsequent waves – would have reached the site in tens of minutes," he added.
The article published in the PNAS newspaper, online Monday, includes among the authors Walter Alvarez, a California geologist, who, with his father, Luis Alvarez, is recognized for helping develop the impact theory for dinosaur extinction.
The Alvarez duet identified a layer of sediment at the border of the Creidium and Paleogene geologically enriched episodes, an element commonly found in asteroids and meteorites.
The remains of iridium would also have covered Tanis deposits.
"When we offered the impact theory to explain the great extinction, only on finding an abnormal concentration of iridium – asteroid fingerprints or comet," said Professor Alvarez. "Since then, the evidence has gradually accumulated, but it never happened to me that we would find a dead bed like this."
"This is one of the most important places in the world at the moment. If you really want to understand the last day of the dinosaurs, that's what it shows," says Phil Manning, from Manchester University, the only author. British in the article. BBC News.
LEARN MORE: Chicxulub Crater – The event that changed life on Earth
• Cleared an object 12 kilometers wide in the Earth's skin with 100 km in diameter and 30 km deep;
• This hole then gave way, leaving a 200km diameter and a few km deep;
• Today, much of the crater is covered by the sea, and below 600m of sediment;
• On land, it is covered with limestone, but its edge is marked by an arch of wells – like wells;
• Recently, scientists have drilled the crater structure to investigate their formation.
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