The catastrophic event that ended the age of dinosaurs 66 million years ago may have unfolded very differently than previously thought. A new study published in the journal Science Advances radically changes our understanding of the mechanism behind the "impact winter" following Earth's collision with an asteroid.

The key to the mystery was the K-Pg boundary — a thin layer of clay found in geological deposits across the planet. This stratum, formed from particles ejected into the atmosphere during the massive explosion, became the primary physical evidence of the celestial body's impact.

The mystery of a rare meteorite

To understand the nature of the cosmic object, scientists conducted a detailed analysis of nickel isotopes in samples of ancient clay. The results revealed a clear chemical marker: the Chicxulub asteroid belonged to the CO chondrite class (Ornan subgroup).

This discovery is of fundamental importance. CO chondrites are primitive rocks that have remained virtually unchanged since the formation of the Solar System. They originate from the distant, debris-rich fringes of our planetary system. Carbonaceous chondrites are rare in themselves, making up only about 5% of all meteorites found on Earth, while CO-class objects are even more exotic.

An error in calculations: why sulfur is not to blame

For a long time, the scientific community adhered to the theory that sulfur gases were the main factor in the extinction. It was believed that the destruction of the asteroid released a huge amount of sulfur into the atmosphere, which effectively reflected sunlight, causing rapid cooling of the planet.

However, the chemical composition of CO chondrites refutes this hypothesis. The sulfur content in such objects is extremely low, making a scenario of global cooling specifically due to sulfate aerosols impossible.

As Philippe Claeys, a co-author of the study and professor at the Free University of Brussels and the University of British Columbia in Vancouver, noted, the new discovery does not negate the fact of mass extinction caused by the impact, but it radically changes our understanding of its physical causes.

The true cause of the icy hell

According to the revised model, the main factors in the formation of the global impact winter were:

  • A dense cloud of dust and soot formed as a result of the explosion.
  • Blocking access to sunlight on the Earth's surface.
  • Cessation of photosynthesis in plants.
  • A sharp and prolonged drop in temperature.

It was precisely this "dark curtain" of soot and dust that destroyed global ecosystems, depriving dinosaurs and many other species of life.

Scientists emphasize that the collision of Earth with such a rare and distant cosmic object only reinforces the perception of the catastrophic and fatal nature of this event. The analysis of the phenomenon continues and remains a subject of sharp debate in the scientific world, forcing us to look at the history of our planet in a new light.