For complex traits, scientists determined that the asteroid impact which formed the Chicxulub crater in Mexico and led to the extinction of the dinosaurs 66 million years ago, had an angle of 45 to 60 degrees to the surface of the Earth. According to the authors, this trajectory contributed to the maximum emission of rocks and deadly gases. The results were published in the journal Nature Communications.
The fall of an asteroid, after which formed the Chicxulub crater, has had a catastrophic effect on the planet’s climate and is believed to have triggered the mass extinction at the turn of the Cretaceous and Paleogene periods, when the face of the Earth, the dinosaurs disappeared.
Scientists from 11 countries have combined data on the shape and subsurface structure of the crater, the geophysical survey results and drilling and on their basis built the three-dimensional dynamic model of impact. They considered the impacts of four options of the angle of approach of the asteroid to the Earth’s surface — 90, 60, 45 and 30 degrees.
This is the first model in the world, which covers all stages of events from the touch of the cosmic body of the Earth to estimate the volume of discarded rocks and gases. Previous three-dimensional model covered only the early stages of exposure.
Based on the results of the calculations, the authors conclude that the Chicxulub crater was formed as a result of steep sloping under 45-60 degrees to the horizon that is falling from the North-East. Simulations showed that in such a strike thrown from the crater material would be distributed almost symmetrically, as observed in fact, and the amount of produced gases per unit weight of the shock body is maximized.
The strike, according to scientists, caused the emission of billions of tons of sulfur into the upper atmosphere, blocking sunlight and triggered the onset of a nuclear winter that killed the dinosaurs and many other species of animals and plants.
"For the dinosaurs it was the worst case scenario — presented in a press release from Imperial College London, the head of research Professor Gareth Collins (Gareth Collins) from the Department of Earth Sciences and engineering — the Blow was accompanied by the release of incredible amounts of climate-altering gases into the atmosphere. This was compounded by the fact that the asteroid fell under one of the deadliest corners".
The calculations were carried out for integrated installation of supercomputer with distributed capacity DiRAC Council for science and technology (STFC) in the UK. The role of the asteroid in the simulation played impactor with a diameter of 17 kilometers with a density of 2630 kg per cubic meter and a flight speed of 12 kilometers per second.
The superficial layers of the crust in the impact area are presented and evaporative porous carbonate rocks containing large amounts of water��. Under the impact and the associated heating of these rocks are decomposed, throwing into the atmosphere huge amounts of carbon dioxide, sulfur and water vapor.
Special danger, according to scientists, was sulphur, which quickly forms aerosol particles that blocks the sun’s rays that led to the halt of the process of photosynthesis and cooling of the Earth’s climate.
The authors hope that the results of their study not only provide new information about the turning point of geological history, when the dinosaurs died, but also allow a better understanding of how formed large craters on other planets.