What killed dinosaurs? It could not have just been a meteorite

The extinction of the dinosaurs, long attributed solely to the impact of a meteorite, is now believed to be a more complex event. A recent study led by Don Baker from McGill University suggests that climate change and massive volcanic eruptions in the Deccan Traps of India may have been significant contributors to the demise of the dinosaurs.

The research, published in Science Advances, indicates that these volcanic eruptions released an immense volume of rock, approximately 1 million cubic kilometers, which could have had a cooling effect on the global climate around 65 million years ago. This prehistoric environmental upheaval, combined with the meteorite impact, likely created a series of catastrophic conditions that the dinosaurs could not survive.

Scientists calculated in the laboratory how much sulfur and fluorine were injected into the atmosphere by massive volcanic eruptions that took place in the 200,000 years before the extinction of the dinosaurs.

The result was surprising, because they discovered that the release of sulfur produced could have caused a global drop in temperature around the world, a phenomenon known as volcanic winter.

"Our research shows that climatic conditions were almost certainly unstable, with repeated volcanic winters that could have lasted decades, before the extinction of the dinosaurs. This instability would have made life difficult for all plants and animals and would have set the stage for the extinction of the dinosaurs,” said Don Baker.

"Therefore, our work helps explain this important extinction event that led to the emergence of mammals and the evolution of our species," he added.

A curious and novel technique

Discovering this information based on ancient rock samples was no easy task. In fact, a new technique developed at McGill helped decode volcanic history.

The technique for estimating sulfur and fluorine emissions (a complex combination of chemistry and experiments) bears some similarities to the process of cooking pasta.

"Imagine making pasta at home. You boil the water, add salt, and then add the pasta. Some of the salt in the water goes into the pasta, but not much," Baker explains.

Similarly, some elements become trapped in minerals as they cool after a volcanic eruption. Just as salt concentrations in the water that cooked pasta could be calculated by analyzing the salt in the pasta itself, the new technique allowed scientists to measure sulfur and fluorine in rock samples. With this information, scientists were able to calculate the amount of these gases released during the eruptions.

Researchers from Italy, Norway, Sweden, the United Kingdom, the United States and Canada participated in the study. Their findings mark a step forward in the attempt to reconstruct Earth's ancient secrets and pave the way for a better understanding of current climate change on the planet.

By the researchers' calculations, that would indicate that a volume of sulfur gas somewhere between 86,000 and 466,000 cubic-kilometers in size erupted into the prehistoric atmosphere.

Did more than an asteroid wipe out dinosaurs?

The recent study has reignited the debate over the cause of the mass extinction that wiped out 75% of Earth’s species, including the dinosaurs, and marked the end of the Cretaceous period. Researchers have long questioned whether the asteroid impact in present-day Mexico was the sole event responsible for this global catastrophe. The alternative theory suggests that massive volcanic eruptions at the Deccan Traps in India might have already set life on Earth on a path to extinction well before the asteroid hit.

Scientists were drawn to the Deccan Traps, a large plateau formed by volcanic lava, to conduct their research. By analyzing rock samples, they were able to estimate the amounts of sulfur and fluorine released into the atmosphere by volcanic eruptions that occurred 200,000 years before the dinosaurs vanished. 

Their findings indicate that the release of sulfur was significant enough to cause a drastic drop in global temperatures, leading to a “volcanic winter” that could have been a precursor to the dinosaurs’ eventual demise.

The catastrophic event that left a six-mile-wide crater, still visible today, brought about a cataclysmic change on Earth. The impact sent 25 trillion metric tons of dust, ash, and steam into the atmosphere, with some debris even leaving Earth’s orbit. The reentry of this material ignited forest fires over 70% of the planet and created massive dust clouds that triggered a new Ice Age, according to scientists.

However, Don Baker’s team suggests that the dinosaurs were already facing adverse climate conditions before the asteroid struck. Their research indicates that a “volcanic-driven climate disturbance” was in progress, hinting that the dinosaurs were contending with challenging weather patterns prior to the impact.

India's connection with dinosaurs' extinction

India’s role in the extinction of dinosaurs has become a topic of significant interest in the scientific community. Recent studies have suggested that massive volcanic eruptions in the Deccan Traps region of India may have contributed to the mass extinction event that wiped out the dinosaurs. These eruptions are believed to have released large amounts of sulfur into the atmosphere, leading to a drop in global temperatures and a “volcanic winter” that could have set the stage for the dinosaurs’ demise.

The debate over whether the asteroid impact alone caused the extinction or if volcanic activity played a role has been ongoing. The new findings add to the evidence that the Earth’s climate was already undergoing significant changes due to volcanic activity before the asteroid struck. This research provides a more nuanced understanding of the events that led to one of the most significant mass extinctions in Earth’s history.

This gradual release likely led to spikes in global temperatures, with increases of up to 10°C occurring within 100,000 years before the Chicxulub meteor impact.

Don Baker, a geochemist from McGill University, explained to Science Alert that their research indicates that the climate was already unstable, with repeated “volcanic winters” that could have lasted decades before the dinosaurs went extinct. This instability would have made survival challenging for all life forms, setting the stage for the mass extinction event.

Keep Reading

Part 1: Cloudburst  in Ganderbal's Padabal village & unfulfilled promises