Washington: Researchers have suggested that the mass extinction at the end of the Permian period, about 250 million years ago, was triggered by contemporaneous volcanic eruptions in Siberia.
New results from a team including Director of Carnegie`s Department of Terrestrial Magnetism, Linda Elkins-Tanton, show that the atmospheric effects of these eruptions could have been devastating.
The volcanic activity was likely episodic, producing pulses of acid rain and ozone depletion. The team concluded that the resulting drastic fluctuations in pH and ultraviolet radiation, combined with an overall temperature increase from greenhouse gas emissions, could have contributed to the end-Permian mass extinction on land.
One leading candidate for the cause of this event is gas released from a large swath of volcanic rock in Russia called the Siberian Traps.
Using advanced 3-D modeling techniques, the team, led by Benjamin Black of the Massachusetts Institute of Technology, was able to predict the impacts of gas released from the Siberian Traps on the end-Permian atmosphere.
Their results indicate that volcanic releases of both carbon dioxide (CO2) and sulfur dioxide (SO2) could have created highly acidic rain, potentially leaching the soil of nutrients and damaging plants and other vulnerable terrestrial organisms. Releases of halogen-bearing compounds like methyl chloride could also have resulted in global ozone collapse.
The study has been published in journal Geology.