when dinosaur– destroy asteroid With the Earth 66 million years ago, huge amounts of matchsticks A new study has found that – larger than previously thought – were thrown high above Earth in the stratosphere.
Once airborne, this huge cloud of sulfur-bearing gases prevented the sun And the earth cooled for decades to centuries, then fell deadly acid rain The study found that the chemistry of the oceans on Earth changed for tens of thousands of years, which is longer than previously thought.
The results show that we “reduced the amount of this sulfur asteroid Study co-author James Waits, a lecturer in the School of Earth Sciences at the University of Bristol in the UK, told Live Science:
As a result, the” Climate change that I was associated with was probably much larger than we previously thought.”
The fact that sulfur has continued to flow at the Earth’s surface for so long may help explain why it takes so long for life, especially marine life, to recover, since some of the sulfur that has fallen to land may then drift into the oceans, Waits said.
The researchers’ findings were completely serendipitous. “It was absolutely nothing planned,” Waits said.
The team had originally planned to study the geochemistry of ancient shells near the Brazos River in Falls County, Texas – a unique place that was underwater during the end.chalky Extinction in non-birds dinosaurs died out.
It’s also not too far from Chicxulub Crater in Mexico’s Yucatan Peninsula, at 6 miles (10 km) wide. asteroid hit.
The researchers took some sediment samples at the site, which they did not plan to do.
These samples were brought to the University of St Andrews in Scotland, where study co-author Aubrey Zerkle, a geochemist and geologist, analyzed different sulfur isotopes, or different forms of sulfur that have a different number of neutrons in their cores.
The researchers found a “very unusual signal” — the isotopes of sulfur had unexpectedly small changes in their masses, Waits said. Such mass changes occur when sulfur enters the atmosphere and interacts with it UV light.
“This can only happen in two scenarios: either in an atmosphere where there are no two scenarios Oxygen Inside it or when you have a lot of sulfur, it turns high into an oxygen-filled atmosphere.”
Earth is about 4.5 billion years old, and it has been enveloped in an oxidizing atmosphere ever since 2.3 billion years ago.
“We’re the first to see this kind of thing recently,” Waits said, at least in sediments not found at Earth’s poles.
(This is because volcanic eruptions release sulfur high into the atmosphere, which can mix with ice and end up in high concentrations in the ice cores at the poles, where there is no sulfur or other sulfur available to dampen the signal, Waits said.)
“you do not see [this signal] in marine rocks. The sea has its own isotopic signature that perfectly dilutes the tiny amount of sulfur from these volcanoes. “
The fact that this signal was found in marine rocks from the Cretaceous period shows that “there must have been a lot of sulfur in the atmosphere after this impact event,” Waits said.
“This of course has a huge impact on Climate change relevant to the effect because sulfur aerosols, which we know from recent volcanic eruptions, cause cooling.”
Much of the sulfur came from the sulfur-rich limestone of the Yucatan Peninsula.
“If the asteroid had crashed somewhere else, there might not have been as much sulfur escaping into the atmosphere Climate change What happened next may not have been that serious, Waits said. Thus, the extinction event may not have been that bad.
Previous estimates of sulfur aerosols entering Earth’s atmosphere after an asteroid impact range from about 30 to 500 gigatons; According to climate models, this sulfur may turn into sulfate aerosols, which could cause the Earth’s surface to cool 3.6 to 14.4 degrees Fahrenheit (2 to 8 degrees Celsius) for a few decades after the impact.
But the new finding suggests that because the amount of sulfur was higher, climate change could be more severe.
The study was published online on Monday (March 21st) in the journal Proceedings of the National Academy of Sciences.