It seems that the fate of the dinosaurs was no ordinary asteroid – although they no longer feel comfortable about it. The celestial body that made a huge wound on the surface of our planet in the Chicxulub impact 66 million years ago was a carbonaceous chondrite, that is, a celestial body with a very rare composition. These celestial bodies were created at the dawn of the solar system, 4.6 billion years ago, and because of their very ancient nature, these meteorites are highly valued by science.
A large international research group is investigating ruthenium isotopes in known meteorites. Compared to themWhich are found in many parts of the world in sedimentary layers formed in connection with the Chicxulub impact. The research was conducted by London Natural History Museum He explained.
Ruthenium is a very rare chemical element on Earth, but meteorites and asteroids contain about a hundred times more of it. In this it is also similar to iridium, which is often used as evidence of impacts, and from its presence the Chicxulub impact theory began a few decades ago.
Based on the approximate traces, the remains of a crater with a diameter of about 150 kilometers, approx. A celestial body with a length of 15 kilometers got here, that is, at a very steep angle. As a result, the substances entering the atmosphere saturated our planet for a long time, and a kind of nuclear winter developed.
According to experts, this was the main reason for the extinction wave. There were many ideas about what kind of celestial body it was and where it came from, but these were mostly inferences based on very little data. For this reason, quite a few people disputed this evidence, and more serious concrete evidence was needed – and this has now been found.
Based on the comparison results, the impacting celestial body was an asteroid whose raw material can be called carbonaceous chondrite. Most impacting meteorites are ordinary chondrites, while carbonaceous chondrites are very rare among them.
This is largely because common chondrites are made of silicate minerals and metals, and can easily survive the journey through our atmosphere to the surface. These common chondrites are thought to have formed in the inner regions of the solar system, and therefore do not contain water or carbon.
A fragment of the carbonaceous chondrite meteorite, the Winchcombe meteorite, which landed in Great Britain a few years ago. The piece is kept at the Natural History Museum in London.
Source: Curators of the Natural History Museum, London
In the case of Chicxulub, the researchers found that the ruthenium isotope ratios were the same as the average isotope ratios of known coal-based chondrites. These celestial bodies come from the outer region of the solar system, beyond Jupiter, so Chicxulub came from there too.
However, even within carbonaceous chondrites there are different types, depending on their water content. The more water they contain, the further they are from the Sun. Ruthenium isotopes also confirm that the colliding celestial body cannot be a comet, because this element is extremely rare in them, similar to Earth.
According to the researchers' hopes, there is a good chance that in the future we will be able to determine which objects Chicxulub might belong to, and this will require more detailed measurements than are currently available. We do not currently have this technique.
Carbonaceous chondrites were much more common in the past, and according to some theories, may have played a major role in delivering water and organic matter to Earth, because during the first billion years of the solar system, carbonaceous chondrites hit Earth much more often than they do today. The fact that Chicxulub arrived so late is presumably due to the fact that the asteroid in question was moved out of its orbit as a result of some kind of gravitational disturbance – which, by the way, Simulation study I already raised it.
