Asteroid Impact :
There has been a never-ending debate about what caused the mass extinction of dinosaurs some 66 million years ago that annihilated more than 75% of total life on Earth.
There were many theses laid out by scientists for years. Among those, a giant asteroid impact and volcanic eruption were majorly suspected to be the prime culprits. The recent study has favored one of these two suspected events to be the actual cause.
Did an asteroid impact really kill the giant lizards?
According to the research published in Proceedings of the National Academy of Sciences, the data on the giant reptiles’ habitats, geological proof, along with the ecological and climate simulations using the latest technology suggest that a giant asteroid impact that created the massive chixulub craters in the Yucatan peninsula in southeast Mexico was the reason for this massive annihilation pulverizing millions of tons of planet’s crust, creating a gigantic death-cloud of dust filling the sky and blocking the sun for many years.
The earth’s temperature reduced drastically triggering decades-long cold winter that obliterated the habitable regions of the dinosaurs making it impossible for them to survive, ruling out “volcanism” to be the major cause.
Paleontologist Alfio Alessandro Chiarenza, University College London, and his team assessed the effect of various impacts including asteroid impact and volcanism.
They simulated dozens of climatic and ecological scenarios and analyzed them with geological evidence to understand the severity of those catastrophic events.
The scientists also found that there were still livable habitats even after a massive asteroid impact, however, the dusty death-clouds blocked 10-15% of the sunlight from reaching the earth’s surface which dramatically cooled global temperatures killing more the 75% of all the plant and animal species at the end of the cretaceous period.
“At 15%, you have the blue screen of death for dinosaurs,” said Chiarenza in a report. He also said that as an asteroid impact-induced winter settled in, the temperatures around the world dropped down to -30° to -40°C.
The research also yielded a twist,’ volcanism’ which was thought to have wiped out most of the living organisms from the face of the earth had actually saved the planet from a long-lasting freezing winter.
After the asteroid impact, volcanism at the Deccan Traps (now India) shrank the devastating effects of the freezing winter by warming the planet way quicker than it would have happened without it.
This made the surviving mammals slowly recover and thrive which became responsible for today’s mammal-dominated world.
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Paleoclimatologist Alexander Farnsworth said, “It’s a complete change in the narrative of Deccan volcanism… which may well have been the benevolent hero of the time.”
The volcanic eruption released hundreds of millions of tons of gases that blocked the sunlight from reaching the surface, however, it also discharged a massive lava river that flowed 100s of thousands of cubic kilometers that warmed the planet.
Tyler Lyson, curator of vertebrate at the Denver Museum of Nature and Science said, “Examining the habitat suitability of various dinosaurs as it relates to the extinction event is new and interesting. But accurately simulating past climate is difficult.“
Upon analyzing the obtained data, the researchers confirmed that an asteroid impact is the most likely cause of the mass extinction.