After a recent study examined the possible connection between mass extinctions on Earth and supernova explosions, as the Inquisitr reported last month, researchers from the University of Bristol in the U.K. have devised a novel strategy of hunting for mass extinction events in our planet’s distant past.
This is virtually the same team who two months ago published a study on the Carnian Pluvial Episode, a mass extinction event that occurred during the Carnian Period, at the beginning of the Late Triassic — and obliterated many of the planet’s tetrapods (some of the earliest mammals to walk on land), ushering in the age of the dinosaurs, the Inquisitr reported at the time.
Their new approach, a statistical method called breakpoint analysis, was tested to confirm the timeline of the Carnian Pluvial Episode and could be used to pinpoint other mass extinction events that shaped the course of life on Earth, notes Science Daily.
How Breakpoint Analysis Works
According to a news release by the University of Bristol, the Carnian event has been difficult to locate in time “because the different sites around the world were hard to date and cross-match.”
But the Bristol team has managed to establish to a fair degree of certainty that the Carnian event took place some 232 million years ago, right between two other mass extinctions — the Permian-Triassic extinction from 252 million years ago and the Triassic-Jurassic extinction that happened 201 million years ago.
To pinpoint the Carnian event in relation to the rise of the dinosaurs, the researchers counted the number of different species of creatures that were alive during the Triassic and analyzed the ratio of dinosaurs in comparison to that of other animals.
“We built a database of 47 faunas from different parts of the world, including 7,773 specimens of reptiles,” says Cormac Kinsella, a researcher who worked on the project and who is now affiliated with the University of Amsterdam in the Netherlands.
— Animal Genetics (@Animal_Genetics) June 13, 2018
In the image above, the red circles represent different Triassic faunas, with the size of each circle mirroring the number of individuals found in each species.
“This method is great,” opines project leader Prof. Mike Benton, from the university’s School of Earth Sciences.
“We know where we think the change occurred, but we don’t tell the computer. We let it crunch the numbers and identify the break point, or the time when one kind of ecosystem ended, and the new one began,” Benton explains.
In this particular case, “it landed precisely on the point in the Carnian when major environmental changes triggered the extinctions,” he points out.
In other words, “the break point was discovered by the statistical model at 232 million years ago, the time of the Carnian extinction,” shows the university news release.
As the scientists point out, the Carnian event was brought on by climate change, triggered by massive volcano eruptions. The shift in our planet’s climate perturbed even the wet-dry cycle of the soil, leading to a decline in succulent, water-loving plants and to the spread of the more resistant conifers that can survive in dry, arid environments.
This shift in the composition of ecosystems was detected in the mid-Carnian and facilitated the reign of the dinosaurs, which ended up dominating the planet, note the Bristol researchers.