Double Trouble: Ancient Volcanic Eruptions Unveil a Fiery Tale of Twin Mass Extinctions

Massive Volcanic Eruption Lava Illustration

An international team of researchers has found evidence suggesting that two mass extinctions, approximately 259 million and 262 million years ago during the Middle Permian Period, were caused by massive volcanic eruptions. The scientists studied uranium isotope profiles of marine samples collected in the South China Sea, which revealed two “pulses” where the oceans were deprived of life-giving oxygen. This research can help predict the potential impact of modern-day global warming on ocean food chains, as human activities release large amounts of carbon into the atmosphere, mimicking the effects of volcanic eruptions. Researchers emphasize the importance of addressing global environmental issues to prevent a sixth mass extinction.

Volcanic eruptions millions of years apart wiped out much of life on Earth.

Massive volcanic eruptions millions of years apart caused two mass extinctions during the Middle Permian Period, according to a study of uranium isotope profiles in marine samples. The findings highlight the potential effects of modern-day global warming on ocean food chains and the importance of addressing environmental issues to prevent further extinctions.

Long before dinosaurs, Earth was dominated by animals that were in many ways even more incredible.

Carnivores such as Titanophoneus, or “titanic murderer,” stalked enormous armored reptiles the size of buffalo.

Many of these animals died out in a mass extinction during the Capitanian Age approximately 260 million years ago.

Now an international team of researchers says evidence suggests this mass extinction was not a single event but two, separated by nearly 3 million years. Both were caused by the same culprit: massive volcanic eruptions.

By studying uranium isotope profiles of marine samples collected in the South China Sea, scientists identified two “pulses” in which the oceans became deprived of life-giving oxygen.

In a study published in the journal Earth and Planetary Science Letters, researchers say their analysis provides evidence that the oxygen-deprived oceans precipitated two mass extinctions around 259 million and 262 million years ago during the Middle Permian Period.

Looming climate disaster

By studying these ancient extinctions, researchers can better predict how modern-day global warming could affect the ocean’s food chain.

“We are studying the biocrisis in the Permian Period, but similar warming is happening today because of human events,” said Thomas Algeo, a study co-author and University of Cincinnati (UC) professor of geosciences. “Humans are mimicking the effects of volcanic eruptions as a consequence of the release of carbon into the atmosphere.”

The study was led by researcher Huyue Song at the China University of Geosciences, a former postdoctoral researcher at UC.

“Today, we are facing several global change issues, including global warming, ocean hypoxia, seawater acidification, and biodiversity decline, which are similar to the environmental changes during the Middle Permian biological crisis interval,” Song said.

Scientists have identified the five biggest mass extinctions, including the most cataclysmic of all 252 million years ago called “the great dying” that wiped out 90% of ocean life and 70% of land animals. This disaster, too, was caused by massive volcanic activity that turned the seas into dead zones, said Algeo.

“The Capitanian extinctions are not among the Big Five, but they are significant,” Algeo said.

How do volcanic eruptions lead to extinctions?

Algeo said massive eruptions create a brief period of cooling from ash in the upper atmosphere reflecting sunlight, followed by much longer periods of global warming. The release of massive volumes of greenhouse gases warmed the oceans. The warm surface water did not allow dissolved oxygen to reach lower depths, eventually destroying the food chain.

“The ocean is teetering on the edge of anoxia,” he said of this absence of oxygen. “Dissolved oxygen has to be taken up by the surface layer and supplied to the deep ocean. But warmer water is lower density. When you increase the density differential, you prevent any overturn and there’s no way to get dissolved oxygen into the deeper layers.”

One way researchers identify these massive volcanic eruptions is by looking for mercury in the sedimentary layers.

“Mercury has been shown to be a useful proxy for volcanic eruptions,” Algeo said. “Large volcanic eruptions spew mercury into the atmosphere that gets carried around Earth and deposited in marine sediments.”

Scientists say the volcanic eruptions that caused the great dying originated in Siberia. The eruptions that caused the twin mass extinctions in the Permian took place in southwest China in a place known as the Emeishan Large Igneous Province.

“Over the last 40 years we’ve made tremendous strides in understanding the Earth’s past.” — Thomas Algeo, UC College of Arts and Sciences

Algeo said he would like to see if any terrestrial evidence supports the conclusions derived from their study of ancient oceans. He is optimistic that geology will unlock more mysteries about prehistoric life on Earth.

“Over the last 40 years we’ve made tremendous strides in understanding the Earth’s past,” Algeo said. “It’s partly because we have all these new tools we can apply. And we have many more people working in this field than we had a generation ago.”

Researcher Song said the dual disasters in the Permian show the devastating effects that global warming can have.

“We must pay attention to these environmental issues and prevent the sixth mass extinction,” he said.

Reference: “Global oceanic anoxia linked with the Capitanian (Middle Permian) marine mass extinction” by Huyue Song, Thomas J. Algeo, Haijun Song, Jinnan Tong, Paul B. Wignall, David P.G. Bond, Wang Zheng, Xinming Chen, Stephen J. Romaniello, Hengye Wei and Ariel D. Anbar, 30 March 2023, Earth and Planetary Science Letters.
DOI: 10.1016/j.epsl.2023.118128

4 Comments on "Double Trouble: Ancient Volcanic Eruptions Unveil a Fiery Tale of Twin Mass Extinctions"

  1. Clyde Spencer | April 10, 2023 at 3:10 pm | Reply

    “Today, we are facing several global change issues, including global warming, ocean hypoxia, seawater acidification, and biodiversity decline, which are similar to the environmental changes during the Middle Permian biological crisis interval,”
    There is an important difference between what is happening today, and what happened during the Permian, especially the End Permian. During the End Permian, and probably the Capitanian, sills of magma were intruded into and around coal beds. The coal released sulfates from the co-existing pyrite, some of which got turned into sulfurous and sulfuric acids, making the oceans actually acidic, not just reducing the alkalinity as is happening now. [This distinction is an important reason why referring to the current minor lowering of pH as “acidification” is poor practice.] Sulfuric acid is a strong acid, in contrast to carbonic acid. The acidity alone could have killed much of the marine life. When it died, it would have used up oxygen, leading to hypoxia. Additionally, toxic volatile hydrocarbons, like benzene and coal tars, were released from the coal, along with toxic mercury, killing plants and animals on land. The dead plant and animal life would have used up oxygen both in the air, and from out-gassing from the oceans as the oxygen partial pressure was reduced, contributing to the hypoxia.

    “We must pay attention to these environmental issues and prevent the sixth mass extinction,”
    The extinctions happening today are not from baking coal and the consequent unrestricted release of sulfuric acid and volatile hydrocarbons, and the mid- to End Permian was very much hotter than what it is today.
    I don’t think that what happened in the Permian is a good analogue for what is happening today.

  2. Finally, research that offers realistic data on the reasons for major extinctions as opposed to the fatuous meteorite impact nonsense…

Leave a Reply to Clyde Spencer Cancel reply

Email address is optional. If provided, your email will not be published or shared.