New research by an international team of scientists adds weight to the idea that the mass extinction event leading to the demise of non-avian dinosaurs was not solely caused by an asteroid impact but was influenced by pre-existing environmental challenges — The study focuses on sulfur levels in the atmosphere, presenting evidence that before the asteroid impact 66 million years ago, the Earth was experiencing significant volcanic activity.
The researchers, led by University of Oslo geoscientist Sara Callegaro, analyzed rocks from the Deccan Traps, a massive volcanic region in present-day West India. Using a new measurement technique for sulfur concentrations, they found that volcanic sulfur degassing from this region could have led to repeated, short-lived global drops in temperature.
The Deccan Traps released an immense amount of molten rock, approximately one million cubic kilometers, with the sulfur-containing lava coinciding with the cooling Cretaceous climate.
The sustained sulfur emissions from this volcanic activity may have substantially altered the global climate, causing temperature fluctuations of up to 10°C within 100,000 years before the asteroid impact.
The findings challenge the traditional narrative that attributes the extinction event primarily to the Chicxulub asteroid impact. Instead, the research suggests that the Earth’s climatic conditions were already unstable due to volcanic activity, creating a series of volcanic winters that could have lasted decades.
This environmental instability likely made survival challenging for both plants and animals, setting the stage for the eventual extinction of dinosaurs.
The study contributes to the ongoing debate between the asteroid and volcano theories regarding the cause of the mass extinction. Some researchers propose that the asteroid impact triggered increased volcanic activity, while others suggest that volcanic activity may have played a role in helping life recover from the asteroid strike.
The research underscores the significance of the Deccan Traps volcanism in shaping global climatic conditions and its role in the lead-up to the mass extinction event.