The great dying: A new study may have revealed the reason behind world's largest mass extinction
According to a new study by Lancaster University, the largest mass extinction event in Earth's history may have been brought on by methane releases produced by volcanic activity burning buried fossil fuel stores.
Massive amounts of high-temperature methane produced by intense volcanic activity may also have contributed to the warming, according to evidence revealed by experts.
More than 90 percent of the marine and more than 75 percent of the terrestrial species perished during the Late Permian Mass Extinction, sometimes referred to as "the great dying," which took place about 260 million years ago, according to a press release published by Lancaster University.
Previous research uncovered evidence that the Late Permian Mass Extinction was primarily driven by massive volumes of carbon emissions generated by volcanoes and that the extinction event was probably caused by the disastrous impacts of an intense period of global warming.
1440 Gigatonnes of methane may have been released
Scientists found out that up to 1440 Gigatonnes of methane may have been released into the atmosphere from the entire basin during the Late Permian era by sampling natural gas wells in the basin, taking into account the volume of gas reservoirs, rock density, and the amounts of pyrobitumen (a by-product of the cracking of oil into methane).
Since methane has a 28-fold greater global warming potential than carbon dioxide over a 100-year period, experts claim this is equivalent to more than 40,410 Gigatonnes of carbon dioxide, or more than 1,000 times the annual carbon emissions.
These significant methane concentrations, according to geologists, may have resulted from subsurface coal and oil deposits being heated by extremely hot volcanic "mantle plumes."
"The novel combination of these isotope techniques in this study provided strong evidence for the generation and emission of high-temperature methane in the Sichuan Basin during the Late Permian," said Dr. Zheng Zhou, Senior Lecturer at Lancaster University and lead author of the paper.
"In Earth's history, large amounts of organic matter were buried underground. Very large quantities of methane could have been generated and released from oil or other organic matter buried underground by heating from mantle plumes," he added.
"Carbon dioxide emissions were a major driver of the global warming and mass extinction, but our findings show that such a large release of methane could have been another key driver of global warming and climate change during the Late Permian and could have contributed to mass extinctions in the past."
They used clumped methane isotope' technique
They computed the creation temperature of the high-temperature methane using the "clumped methane isotope" method, and they discovered that it was approximately 256°C. The fact that these temperatures were higher than those typically encountered during the geological history of the gas reservoir's burial suggests the presence of an extra heating source.
Further study is required, the researchers say, to comprehend methane emissions from other locations linked to mantle-related activity as well as to look into the global distribution and consequences of high-temperature methane.
The study was published in Nature Communications on November 12.
Methane (CH4) emissions induced by Large Igneous Provinces have the potential to contribute to global environmental changes that triggered mass extinctions in Earth's history. Here, we explore the source of methane in gas samples from central Sichuan Basin, which is within the Emeishan Large Igneous Province (ELIP). We report evidence of high methane formation temperatures (between 249−17/+19 and 256−20/+22 °C) from clumped methane measurements and mantle-derived signatures of noble gases, which verify that oil-cracked CH4 and pyrobitumen are by-products within the reservoirs, associated with hydrothermal activity and enhanced heating by the ELIP. We estimate the volume of oil-cracked CH4 induced by the ELIP and argue that CH4 emissions would have been sufficient to initiate global warming prior to the end of the Permian. We also suggest that similar emissions from oil-cracked CH4 associated with the Siberian Traps Large Igneous Province may also have contributed to the end-Permian mass extinction significantly.
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