The impact of two large asteroids on Earth 35 million years ago did not change its climate in the long term. This is according to the results of a study published in the journal Communications Earth & Environment.
35 million years ago, the Earth suffered a double impact when two large asteroids collided with it about 25,000 years apart. The first object, with a diameter of 5 to 8 km, fell in Siberia and left behind a 100-kilometer Popigai crater. The second asteroid had a diameter of 3 to 5 km. Its fall led to the formation of the 85-kilometer-long Chesapeake Crater on the east coast of North America.
A team of researchers decided to answer the question of how these events influenced the Earth’s climate. For this purpose, they analyzed more than 1,500 fossilized single-celled organisms called foraminifera — both those that lived near the ocean surface (planktonic foraminifera) and on the seafloor (benthic foraminifera). They were discovered in three-meter-long rock cores taken from the bottom of the Gulf of Mexico. Their age ranges from 35.5 to 35.9 million years.
Scientists were interested in the content of carbon and oxygen isotopes. Their structure reflected how warm the waters were when the organisms were alive. The analysis showed that in the 100,000 years before the two asteroid impacts, surface ocean temperatures increased by about two degrees Celsius, while deep-sea temperatures decreased by one degree.
But to the surprise of the team of scientists, they were unable to detect any long-term climate shifts either during or after the collisions. At the same time, scientists managed to find traces of the hits themselves in the form of thousands of tiny glass droplets. They were formed by the condensation of matter vaporized and released into the atmosphere by asteroid impacts.
At the same time, the scientists point out that their study would not have detected shorter-term climate changes on a time scale of tens or hundreds of years because samples were taken every 11,000 years. On the scale of human life, however, the consequences would be catastrophic. The asteroid impact caused massive shock waves, tsunamis and widespread fires, and large amounts of dust rose into the air, blocking sunlight and causing global cooling.
The results of the study converge with modeling of the effects of an asteroid impact that formed the Chicxulub crater. This impact is believed responsible for the extinction of the dinosaurs. Modeling showed that by geological standards, the resulting climate change was short-lived, lasting no more than 25 years.
Provided by Phys.org
