A team of international researchers uncovered data through geological studies suggesting that the previously held timeline for the end-Permian mass extinction is in need of reworking.
The end-Permian extinction, which is believed to have occurred before dinosaurs existed, killed more than 96% of marine life and 70% of land species.
“We’ve been able to put together a more complete picture of what happened during the latest Permian in South Africa on land,” said Robert Gastaldo, a geology professor at Colby College in Maine. “That record is now able to be compared with a record that was produced in Eastern Australia.”
This research was initially influenced by a published hypothesis regarding the collapse and disappearance of vegetation during the end-Permian extinction.
The hypothesis claimed that after this extinction of plants and vertebrates, following vertebrates evolved into a more diverse group even in the absence of plants. As most of the vertebrates were herbivores, however, scientists realized this response did not make biological sense.
In 2003, Gastaldo began working on this project in South Africa as a research participant. By 2005, he had applied for his own funding and became the principal investigator. The study was thus funded primarily through various grants by the U.S. National Science Foundation.
“We now know after 18 years of research … that whatever happened to the plants, and maybe to the animals, … did not happen at the same time of the greatest mass extinction in Earth’s history that occurred in the oceans,” Gastaldo said. “Whatever happened on land happened 300,000 years, or maybe a little more, before the catastrophe in the ocean.”
The team consists of researchers from all over the world, including UC Berkeley’s Cynthia Looy, an associate professor in the integrative biology department.
Members of this group participated in research trips to South Africa over the years to study volcanic ash deposits in the Karoo Basin.
“It was really, really amusing to see this troop of baboons just clamoring and making all sorts of noise about 25 meters away from where I was sampling one site,” said John Geissman, a geosciences professor at the University of Texas at Dallas. “It was a baboon sitting on top of a termite mound taking a s—, and all its friends were laughing. It was kind of cool.”
Before this research took place, the existing fossil beds had not been dated with solid numbers, according to Johann Neveling, a participating researcher and chief scientist at the Council for Geoscience in South Africa.
When the ash beds in the basin were discovered and their determined age was older than previously thought, the findings led researchers to suspect that the fossil beds may actually be too old to be linked with the end-Permian mass extinction.
“There will be, at least to some extent, a little bit of sadness that the Karoo can no longer lay claim to having preserved the best record of the terrestrial version of the End-Permian mass extinction,” Neveling said in an email.
Neveling added that scientists are “no different from other people” and take pride in being able to make that claim.
With this new information, Neveling hopes that the Karoo rocks may now help answer existing questions regarding mass extinction on land, the search for the true end-Permian boundaries and the contact between certain fossil communities.
“A decade and a half later, I find myself still tinkering in this field,” Neveling said in the email. “I never thought it would last this long.”