In a new study, scientists have tested the long-held belief that sulfur eruptions, among other things, caused a severe, prolonged “shock winter,” writes Success in UA.
Researchers now believe that earlier studies likely overestimated the amount of sulfur that was actually released.
When a huge asteroid slammed into Earth, it sent a cloud of dust, soot, and other materials into the atmosphere, creating what scientists call a “shock winter.” Essentially, the planet is plunged into extreme cold and darkness at this point: plants can’t photosynthesize, and animals can’t thrive. In the case of the Chicxulub asteroid, its impact caused a complete rearrangement of the animal order, according to a new study. focus.ua.
In this destructive dust cloud, scientists have previously singled out a particularly “extinction-causing agent”: sulfur. However, the exact amount of sulfur released is still a matter of debate, and estimates vary widely. The main questions that remain unanswered are: whether there were many sulfur-filled rocks at the impact site; how fast and at what angle the asteroid fell; and what this might mean for the subsequent distribution of sulfur.
In the new study, scientists used cores extracted from impact rocks at the Chicxulub site in Mexico. The authors of the study say their work is the first ever empirical way to estimate how much sulfur was actually released during the asteroid impact.
According to study co-author, chemist Kateryna Rodyushkina, she and her colleagues focused not on the impact event itself, but on its aftermath. They first analyzed the sulfur footprint of rocks in the area of the craters, which were the source of sulfate aerosols ejected into the atmosphere.
These aerosols spread around the world and were eventually ejected from the atmosphere back to the planet's surface within months, and possibly years, after the impact. Sulfur was deposited around the K-Pg boundary layer in sedimentary profiles around the world. In the study, the scientists used the corresponding change in sulfur isotopic composition to distinguish that associated with the impact from natural sources. As a result, the total amount of sulfur ejected was calculated using a mass balance.
The team concluded that previous estimates were overestimated, with some exceeding the new results by a factor of 5. The team estimates that a total of 67 ± 39 billion tons of sulfur were ejected, suggesting that this was followed by a milder impact winter than previously thought.
Simply put, the planet's temperature still dropped, but probably not as dramatically, and the climate would have returned to near-normal much sooner than previously thought. The study's authors also believe their discovery could explain why, despite all the drama, a quarter of life on Earth managed to survive.