A study published by PNAS suggests that only the impact of the asteroid could have created unfavorable conditions for dinosaurs worldwide
Madrid.- Millions of years after its extinction, there is still debate about what caused the disappearance of the dinosaurs. Now, a new study reinforces the idea that the main reason was the impact of an asteroid, which created an uninhabitable world for these animals, and not the effect of volcanoes.
The collision of the asteroid Chicxulub on the shores of Mexico 66 million years ago it is traditionally considered the cause of the extinction of all species of dinosaurs, except for those flying.
However, in recent years, some researchers suggested as a culprit a large episode of volcanism that occurred in the Deccan Traps (India), for tens of thousands of years, which killed 75% of the terrestrial species and, therefore, could also have done it with the dinosaurs.
A study published by PNAS suggests that only the impact of the asteroid could have created unfavorable conditions for the dinosaurs Worldwide.
In addition, large-scale volcanism could even have helped life recover after the Chicxulub impact, according to researchers at Imperial College London and the University of Bristol who sign the text.
The lead author of the research, Alessandro Chiarenza, explains that the asteroid caused an eternal winter for decades, which « ended up with the right environments for dinosaurs they lived. «
However, « the effects of the intense volcanic eruptions were not strong enough to alter the global sustainability of ecosystems. »
« Our study confirms, for the first time quantitatively, that the only plausible explanation for the extinction » is the long winter that ensued after the asteroid hit, which « eradicated the habitats of the dinosaurs around the world, « he adds.
The asteroid’s impact released particles and gases into the upper layers of the atmosphere, which blocked sunlight for decades, causing a permanent winter, the researchers explain.
Volcanic eruptions also produce particles and gases that blind sunlight, but also release carbon dioxide. A combination that, in the short term, can create a volcanic winter, but in the long term, when only CO2 remains and accumulates in the atmosphere, it warms the planet.
To determine which factor – asteroid or volcanism – had more power of climate change, they used methods such as geological markers and mathematical models, which they combined with information on environmental factors – precipitation and temperature – than the dinosaurs they needed to prosper.
The authors studied where on Earth, after the impact of a large meteorite or a major episode of volcanism, the conditions that these animals needed to survive could continue to exist.
The models indicated that the impact of an asteroid erased all potential habitats in the world, while volcanism left some viable regions for these animals around the equator.
Furthermore, the team believes that the long-term effects of the volcanic episode helped restore life on Earth.
The models used in the study suggest that, after a drastic global winter caused by the asteroid’s impact, the CO2-warming from the volcanism may have helped restore many habitats from the effects of the meteorite.
Chiarenza notes that the warming caused by the volcano « helped boost the survival and recovery of plants and animals. »