A new University of Leeds study has shown that volcanic activity wasn’t a significant factor in the death of thousands of species and dinosaurs during mass extinctions. The two major causes of mass-extinction events are believed to have been the impact from long-lasting volcanic eruptions and asteroids. However, no one knew the effects of the many years of sulphur dioxide emission from continental flood basalts. The impact of continental flood basalts on dinosaurs and other animals was less than previously thought. (Image: University of Leeds). A group of scientists has published in Nature Geoscience a first-ever quantitative assessment of the impact of such volcanic eruptions on the climate, oceans, and vegetation of our planet. Not like the current volcanic eruptions. Dr. Anja Schmid, head of the University of Leeds School of Earth and Environment explained that the continental flood basalts were not similar to today’s volcanoes. The ‘continental flooding basalts’ eruptions are not the same as today’s volcanic eruptions. Lava gushing out of the ground was like an Olympic-sized curtain of fire. “The eruptions probably lasted many years or even decades and were separated by periods with no volcanic activity. An average-intensity eruption would have produced lava that could fill 150 Olympic sized swimming pools every minute. This latest study by scientists showed that flood basalts had less of a climatic impact than previously thought. Schmidt and his colleagues discovered that if flood basalts had oozed for many hundreds of years, the climate impacts could have been enough to impact the survival of animals and plants. To estimate the environmental effects and climate impacts of massive amounts of sulfur dioxide gas that were emitted from those volcanic eruptions, the team relied on data about the frequency and intensity of these continental flood basalt eruptions. This included the Deccan Traps explosions that took place one-third of India today. The large asteroid that struck Earth 65 millions years ago, causing the Chicxulub volcanic crater to form on Mexico’s Yucatan Peninsula created the end of the dinosaurs. Their computer simulation showed that temperatures were actually cooler due to volcanic activity, by up to 4.5 degrees Celsius. However, the temperature would recover to its normal level within half a decade after an eruption had stopped. Dr. Schmidt noted with his team that these conclusions were based upon the assumption that climate feedbacks would be very similar today to what they were back then. Acid rain selective Dr. Schmidt stated that acid rain had a selective effect on plants. Dr. Schmidt stated that acid rain had a selective effect on vegetation. This is despite the fact that it would have caused some areas of the globe to die off. Dr. Schmidt stated that “we now need to understand how long each individual eruption and periods without volcanism lasted.” Nature Geoscience (2015), 23 December, 2015. DOI: 10. 1038/ngeo2588.
