Researchers have found a geological record of the most pivotal moment in Earth’s history. Study lead author Sean Gulick, a research professor at the University of Texas Institute for Geophysics, called the finding “the most detailed look yet into the aftermath of the catastrophe that ended the Age of Dinosaurs.” The details of the study have been published in the peer-reviewed journal Proceedings of the National Academy of Sciences.
The study provides details of the day an asteroid smashed into the Earth 66 million years ago. The asteroid hit just offshore of Mexico’s Yucatán Peninsula at roughly 45,000 miles an hour. The impact sent out a flash of energy that ignited wildfires within a 900 miles radius. It also triggered a massive tsunami that reached as far inland as Illinois.
Researchers estimate the asteroid hit with the power of 10 billion atomic bombs. The aftereffects of the impact killed 75 percent of all species on Earth, including the dinosaurs. Hundreds of feet of rocks filled the impact crater within the first 24 hours after the strike. It is these rocks the researchers examined for their study.
A scientific drilling mission, co-led by Gulick and Joanna Morgan, retrieved a core sample about a half-mile long from the impact site in 2016. The researchers subjected the sample to a battery of tests, including geochemical study and x-ray imaging. They found melted and broken rocks such as sandstone, limestone and granite, along with bits of charcoal later left by raging wildfires.
Surprisingly, the team found no sulfur-bearing minerals, despite the area’s high concentration of sulfur-containing rocks. This appears to indicate that the impact vaporized these rocks, releasing as much as 325 gigatons of sulfur into the atmosphere. This haze of sulfuric acid could have triggered years of global cooling or created acid rain that abruptly acidified the oceans.
Further study in the coming years of the core samples and other evidence will likely provide much more information about the days after the impact and the effects it had on the environment.