New Delhi: The conventional theory on the emergence of dinosaurs is that excessive volcanism 201.6 million years ago from a region now called the Central Atlantic Magmatic Province (CAMP), injected excessive amounts of carbondioxide in the atmosphere, resulting in a greenhouse Earth during the transition between the Triassic and Jurassic periods. The excessive volcanism caused a mass extinction event, opening up ecological niches for the dinosaurs to evolve into and occupy. Researchers believed that millions of cubic miles of lava erupted over a period of 600,000 years, injecting carbon dioxide buried over millions of years into the atmosphere, acidifying the oceans. New research now indicates that the opposite was true, the aerosols injected into the atmosphere during the Triassic-Jurassic transition period resulted in a period of global cooling.
The new research presents evidence that the volcanism did not stretch over hundreds of thousands of years, but was instead more sharp, spewing sulfate particles into the atmosphere. This blanket would have frozen the plants and animals on the surface, with a gradual warming and carbon dioxide saturation finishing off the life that remained. The main culprit for the mass extinction though, was global cooling and not global warming. The research is based on careful study of the minerals from the Triassic-Jurassic boundary, that act as fossils for the magnetism at that time, allowing scientists to estimate the period of excessive volcanism.
Global cooling by sulfates caused the end-Triassic mass extinction
A paper describing the findings has been published in the Proceedings of the National Academy of Sciences. Lead author of the paper, Dennis Kent says, “Carbon dioxide and sulfates act not just in opposite ways, but opposite time frames. It takes a long time for carbon dioxide to build up and heat things, but the effect of sulfates is pretty much instant. It brings us into the realm of what humans can grasp. These events happened in the span of a lifetime.” There is mounting evidence to indicate that excessive volcanism, and not an asteroid strike, was the primary driver of the extinction of the dinosaurs as well.
