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Researchers from North America and China determined the date and rate of Earth’s most severe mass extinction. A paper in this week’s journal Science provides the findings.
About 95 percent of marine life and 70 percent of terrestrial life became extinct during what is known as the end-Permian, a time when continents were all one land mass called Pangea. The environment ranged from desert to lush forest. Four-limbed vertebrates were becoming diverse and among them were primitive amphibians, reptiles and a group that would, one day, include mammals.
End-Permian Earth (Christine Daniloff)
Through the analysis of various types of dating techniques on well-preserved sedimentary sections from South China to Tibet, researchers determined that the mass extinction peaked about 252.28 million years ago and lasted less than 200,000 years, with most of the extinction lasting about 20,000 years.
“These dates are important as it will allow us to understand the physical and biological changes that took place,” says Dr. Charles Henderson, professor in the Department of Geoscience at the University of Calgary. “We do not discuss modern climate change, but obviously global warming is a biodiversity concern today. The geologic record tells us that ‘change’ happens all the time, and from this great extinction life did recover.”
There is ongoing debate over whether the death of both marine and terrestrial life coincided, as well as over kill mechanisms, which may include rapid global warming, hypercapnia (a condition where there is too much CO2 in the blood stream), continental aridity and massive wildfires.
The conclusion of this study says extinctions of most marine and terrestrial life took place at the same time. And the trigger, as suggested by these researchers and others, was the massive release of CO2 from volcanic flows known as the Siberian traps, now found in northern Russia.
Source link: https://www.sci.news/paleontology/earths-largest-mass-extinction-dated.html
Source link: https://vietnet.org/earths-largest-mass-extinction-dated/
