“Supereruptions” are normally associated with heat, and understandably so. Whether they are quick, explosive, and feature pyroclastic flows, or they’re slow, effusive, and characterized by rivers of lava, many of them inject a considerable amount of carbon dioxide into the atmosphere, triggering global warming events.
There are those that also unleash a lot of sunlight-reflecting sulfur aerosols into the air, which initiates rapid global freezing. Take the eruption in Greenland, 717 million years ago, for example, that turned the planet into a gigantic snowball.
The CRFB was more like the latter than the former. It helps to explain a near-unprecedented cooling event that has been left without a viable antagonist ever since it was discovered.
You may have noticed that it’s termed a “flood basalt”. Emerging from fissures as fire fountains and lava flows, these eruptions build into a fiery sheet that seems to perpetually emerge from the hellish bowels of the planet.
This particular event was the third most significant flood basalt on the planet, topped only by the Deccan Traps – the one that accompanied the asteroid strike that finished off the age of the dinosaurs – and the Siberian Traps – the one that triggered the Great Dying, the most severe mass extinction ever known. Unlike the CRFB, these two events both chilled then boiled the planet by releasing a combination of sulfur aerosols and greenhouse gases.
In any case, whether it’s serious warming or serious cooling, it’s clear that flood basalts have the power to change the world and bring about an era of death – far more so than any explosive, Yellowstone-like supereruption.
Had the planet not enjoyed a 50 million year warming period at the time of the CRFB, there’s a chance it could have led to yet another mass extinction, one that might have altered the course of evolution in ways we can only imagine.