The Chicxulub Crater, hidden under the Gulf of Mexico, points to the location of an asteroid that struck Earth 66 million years ago. The most important result of this cataclysm event is Fifth mass extinctionWipe out about 80% of all animal species, including non-birds dinosaur..
But what actually happened when the asteroid collided with Earth?
By studying geology both in Chicxulub and around the world, scientists have summarized what happened in that horrifying day and in the years that followed.
Even before the asteroid collided, it was prepared for decimation and collided with the Earth at the most destructive angles. Nature Communications.. The asteroid was about 7.5 miles (12 km) in diameter and was moving about 27,000 mph (43,000 km / h) when it made a 124-mile (200 km) wide scar on the surface of the planet, says research professor Sean Gulick. I am. At the Institute of Geophysics, University of Texas, who led the study. More importantly, the asteroid collided with the planet about 60 degrees above the horizon. This angle was particularly destructive, as the impact of the asteroid allowed large amounts of dust and aerosols to be released into the atmosphere.
Glick is his colleague evidence The asymmetric structure of the crater, the location of the upwardly bent (upwardly bent) mantle rocks, the unique sequence of sediments of the core collected from this area, especially the unique evaporites in the core, such as rock salt and gypsum. Type of rock.
Gulick’s team estimated that the impact would evaporate the evaporite and send 325 gigatons of evaporite. sulfur In the form of sulfur aerosols, 435 gigatons of carbon dioxide are released into the atmosphere.
According to a 2014 study published in the journal, materials released into the atmosphere were mainly crushed rocks from sulfate-rich marine rocks known as anhydrite that evaporated during asteroid collisions. It consisted of droplets of sulfuric acid. Nature Geoscience.. This microscopic cloud of matter created a cover around the planet, reducing incoming solar heat and light. The resulting long-term cooling has dramatically changed the planet’s climate.Journal 2016 study Geophysics Research Letter It was found that the average temperature in the tropics plummeted from 81 degrees Fahrenheit (27 degrees Celsius) to 41 degrees Fahrenheit (5 degrees Celsius). When the incoming sunlight dim, photosynthesis It has declined, the foundations of the land and sea food chains have collapsed, and dinosaurs and many other animals have fallen.
On the other hand, air sulfuric acid Deadly acid rain According to a 2014 survey, it rained for several days after the impact, killing countless marine animals in the upper seas and in lakes and rivers.
The impact also caused a large tsunami, a wave of shallow water propagating the Earth’s oceans. The waves first reach a height of about 1 mile (1.5 km) and travel 89 mph (143 km / h), while other waves travel up to 46 feet (15 m) and 13 feet (4 m) in the Atlantic Ocean. Reached a huge height including. In the North Pacific According to modeling research.. In addition, evidence of sedimentation from giant waves is preserved in sedimentary records around Louisiana. A 3D seismic survey of Louisiana’s geology revealed a long, asymmetrical 52-foot (16 m) high. Mega Ripple It points to the Gulf collision site.
And the fire was furious
Crushed stone and ash flow down to the surface after collision Ignite a series of wildfires The researchers likened it to a broiler that ignites a dry crater. Additional smoke and ash may have contributed to the cooling of the shroud, further reducing incoming sunlight.
Geologists can easily see when an asteroid hit when examining a rock formation.In rocks around the world dating back to the end Cretaceous 66 million years ago, there are abundant thin layers of clay iridiumA groundbreaking 1980 study published in the Journal, an element that is rare on Earth but common among rocks in the universe. Chemistry found. But while other epic events such as wildfires and tsunamis stir the imagination, Gulick believes that changes in the Earth’s atmosphere were a bigger problem. There, a terrifying cover led to cooling that lasted more than a decade.
“The only way to have a mass extinction event is to ruin something that affects the entire planet,” he said. “Here is direct evidence that it is happening.”
Originally published in Live Science.
What happened when the dinosaur-killing asteroid crashed into Earth?
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