Mass extinction event from South Africa's Karoo

Mass extinction event from South Africa's Karoo
An illustration of the Guadalupian extinction. Credit: Wits University

An international team led by researchers from the Evolutionary Studies Institute (ESI) at the University of the Witwatersrand, Johannesburg, has obtained an age from rocks of the Great Karoo that shed light on the timing of a mass extinction event that occurred around 260 million years ago.

This led to the disappearance of a diverse group of early mammal-like reptiles called dinocephalians, which were the largest land-living animals of the time.

The project was led by Dr Michael Day, a at Wits University, and the findings are contained in paper, titled: When and how did the terrestrial mid-Permian occur? Evidence from the tetrapod record of the Karoo Basin, South Africa, published today, 8 July 2015, in the latest issue of the Royal Society's biological journal, Proceedings of the Royal Society B.

The Karoo is very rich in fossils of from the Permian and Triassic geological periods, which makes it one of the few places to study extinction events on land during this time. As a result South Africa's Karoo region provides not only a historical record of biological change over a period of Earth's history but also a means to test theories of evolutionary processes over long stretches of time.

By collecting fossils in the Eastern, Western and Northern Cape Provinces the team was able to show that around 74-80% of species became extinct along with the dinocephalians in a geologically short period of time.

The new date was obtained by high precision analyses of the relative abundance of uranium and lead in small zircon crystals from a volcanic ash layer close to this extinction horizon in the Karoo.

Mass extinction event from South Africa's Karoo
Professor Bruce Rubidge is a Karoo fossil expert from the Evolutionary Studies Institute at Wits University. Credit: Wits University

This provides a means of linking the South African fossil record with the fossil record in the rest of the world. In particular, it helps correlate the Karoo with the global marine record, which also records an around 260 million years ago.

"A mid-Permian extinction event on land has been known for some time but was suspected to have occurred earlier than those in the marine realm. The new date suggests that one event may have affected marine and terrestrial environments at the same time, which could mean its impact was greater than we thought," says Day.

The mid-Permian extinction occurred near the end of what geologists call the Guadalupian epoch that extended from 272.3 to around 259.1 million years ago. It pre-dated the massive and much more famous end-Permian by 8 million years.

Mass extinction event from South Africa's Karoo
Dr. Michael Day with a skull of Anteosaurus found close to the extinction interval on the Nuweveld Escarpment north of Merwevillle, Western Cape Province. Credit: Wits University

"The South African Karoo rocks host the richest record of middle Permian land-living vertebrate animals. This dataset, the culmination of 30 years of fossil collecting and diligent stratigraphic recording of the information, for the first time provides robust fossil and radioisotopic data to support the occurrence of this extinction event on land," says Day.

"The exact age of the marine extinctions remains uncertain," says Jahandar Ramezani of Massachusetts Institute of Technology and who was responsible for dating the rocks, "but this new date from terrestrial deposits of the Karoo, supported by palaeontological evidence, represents an important step towards a better understanding of the mid-Permian extinction and its effect on terrestrial faunas."

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Geologic Findings Undermine Theories of Permian Mass Extinction Timing

More information: When and how did the terrestrial mid-Permian mass extinction occur? Evidence from the tetrapod record of the Karoo Basin, South Africa , rspb.royalsocietypublishing.or … .1098/rspb.2015.0834
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Jul 07, 2015
The scariest Mass Extinction is the one we are in.

Jul 08, 2015
The scariest Mass Extinction is the one we are in.

Why? MEs take a million years, more or less. With any luck we will be a Kardeshev II in 1% of that time.

Stop drinking the marxist koolaide. It'll give you heartburn.

Jul 08, 2015

You wouldn't know science if it hit you in the ass. You would have a hell of a headache though.

Jul 08, 2015
The scariest event we are in, is the mass stupidity of the AGW Cult.

Jul 08, 2015
Shootist thinks it is okay to have another Mass Extinction, because he will be dead already, not caring about anyone else, or anything else.

Jul 08, 2015
The scariest Mass Extinction is the one we are in.

Here is a simple question for you AGW Chicken Littles.
What has gone extinct to constitute a mass extinction?

Jul 11, 2015
It's impossible for fossils to form over millions of years. The organic material would decay before it had a chance to fossilize. Fossils can only form with catastrophic events. It has to be done fast

What kind of event exactly? How do they form in said event? Step by step walkthrough of it would be appreciated, as well as the supporting scientific data of course.

Jul 11, 2015
I love the sheer number of nutters on these posts. I don't know why you guys bother trying to debate them. Reverse-indoctrination is difficult if not impossible. Your neural circuitry is baked in pretty early usually by the extreme logical fallacies and inconsistencies one is bombarded with during a religious or non-rational upbringing. They're lost causes, and probably have mental / intellectual issues driving them to the dusty corners of obscure science websites.

Jul 11, 2015
xstos, it is emotion and ignorance which drives them. They are the goobers who got SCARED by Bush and Cheney, who were themselves SCARED by the Vietnam War, and their possibility of actually having to serve.

Ignorance of science allows their emotional manipulation.

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