The Formation of Earth’s Extinction Crater by a Carbon-Rich Asteroid
When a massive space rock slammed into Earth 66 million years ago, it wiped out huge swathes of life and ended the reign of the dinosaurs. Now, scientists say they have new insights into what it was made from. Experts studying material laid down at the time of the event say they have found tell-tale signs to support the idea that the Chicxulub impact crater was produced by a carbon-rich, “C-type”, asteroid that originally formed beyond the orbit of Jupiter.
New Insights into the Chicxulub Impact Crater
Mario Fischer-Gödde, co-author of the research from the University of Cologne, explained that the team is now keen to look at deposits associated with an impact some suggest was behind a large extinction about 215 million years ago. This research aims to determine if C-type asteroid impacts would have a higher probability of causing mass extinction events on Earth.
In a study published in the journal Science, researchers reported how they studied different types, or isotopes, of ruthenium within a layer of material that settled over the globe after the impact 66 million years ago. Fischer-Gödde stated, “This layer contains traces of the remnants of the asteroid,” highlighting the significance of the findings.
Ruthenium as a Key Element in Determining Asteroid Composition
The team focused on ruthenium as the metal is very rare in the Earth’s crust, making it almost 100% derived from the asteroid. This offers scientists a way to determine the makeup, and hence type, of the impactor itself. Samples of the layer from Denmark, Italy, and Spain all showed the same ruthenium isotope composition, providing crucial evidence to support their theory.
Furthermore, the team’s analysis ruled out the theory that the presence of ruthenium and other metals such as osmium and platinum are due to past eruptions of the Deccan Traps volcanoes. The researchers also cast doubt on the possibility that the impactor was a comet, as the ruthenium isotope composition of the samples is different from meteorites thought to be fragments of comets that have lost their ice.
Confirmation of a Carbon-Rich Asteroid Origin
Instead, the ruthenium isotope findings align with the average composition of meteorites from carbonaceous (C-type) asteroids – carbon-rich space rocks that formed at the beginning of the solar system beyond the orbit of Jupiter. This confirmation sheds light on the nature of the impactor that struck Earth 66 million years ago, leading to a mass extinction event.
Questions Remain about the Asteroid’s Origin
While the composition of the asteroid has been determined, questions remain about where exactly the asteroid came from before it headed to Earth. Fischer-Gödde suggested that C-type asteroids can be found in the asteroid belt between Mars and Jupiter, as Jupiter’s migration scattered asteroids in the process shortly after the formation of the solar system.
One possible scenario proposed by Fischer-Gödde is that there was a collision of two asteroid bodies in the belt, and then a chunk went on an Earth-crossing orbit. This theory provides insight into the potential trajectory of the ill-fated space rock that caused the Chicxulub impact crater. However, there are other possibilities, including the asteroid originating from the Oort cloud that surrounds the solar system.
Exciting Research on Earth’s History
Dr. Craig Walton of the University of Cambridge, who was not involved in the study, expressed excitement about the research findings. While it remains unclear whether the impactor was an asteroid or comet, the detailed insights into the nature of objects that have shaped Earth’s history are invaluable. The ongoing research in this field continues to provide new perspectives on the events that have shaped our planet’s evolution.
In conclusion, the study on the formation of Earth’s extinction crater by a carbon-rich asteroid sheds light on a significant event in our planet’s history. By analyzing isotopes of ruthenium in material deposited after the impact, scientists have been able to confirm the origin of the impactor as a carbonaceous (C-type) asteroid. This research contributes to our understanding of the impact events that have shaped Earth and highlights the importance of studying celestial bodies to comprehend our planet’s past.