A Dartmouth College and UC Berkeley study revealed a correlation between mass extinctions and large-scale volcanism throughout history.
Specifically, the researchers were able to quantitatively show that large igneous province eruptions are correlated with extinction. They found that the as the rate of eruption increased, so did the severity of the extinction.
“People, including myself, have been able to date these occurrences of this extreme volcanic activity with increasing precision,” said Paul Renne, co-author and director of the Berkeley Geochronology Center. “One can now really test for causality or at least coincidence with unprecedented accuracy, so that’s what we did.”
This research was conducted, according to Renne, through the use of data mining. The researchers ran several statistical tests and random distributions of the occurrence of volcanic episodes, coinciding with when mass extinction occurred.
Theodore Green, lead author and current graduate student at Princeton University, added that high-precision geochronology is essential for their work in order to correlate specific eruptions with specific extinction events.
“It makes a really strong case that in order to really prove what causes effects like mass extinctions, or climate change, or anything else that we can learn about from the geologic past, the ability to accurately and precisely date these phenomena is absolutely critical,” Renne said.
The volcanic eruptions the researchers studied are not just typical one-and-done eruptions. According to Renne, large-scale volcanism results in either continental flood basalts or occasionally massive igneous provinces. Lava erupts continuously in these areas for 1 million years and reaches accumulations of lava as thick as five kilometers and as wide as 10 kilometers.
Despite these eruptions leading to mass extinctions throughout history, those conditions might not be comparable to the environmental conditions humans have created in the present day, Renne explained.
“If we can show that the factors that we know cause climate change naturally in the absence of human activity have never created the kinds of conditions that we see now, we’re kind of left with the only conclusion being that this is the result of human activities,” Renne said.
The researchers hope to be able to repeat their analysis as more geochronologic data is generated for the large igneous provinces, according to Green. This will allow them to see how increased precision impacts their calculations.
Further study of how large igneous provinces are tied to other environmental changes — including ocean anoxic events or hyperthermal intervals — is also a possible area of focus for geochronology in the future, according to Green.
“There’s definitely still a lot of cool work to be done on many large igneous provinces to get a better sense of when exactly they were erupting, including whether they erupted continuously or in time-separated pulses,” Green said in an email.