Extinction event: Why NZ scientists are studying a prehistoric apocalypse in Antarctica

• Kiwi scientists are heading to Antarctica next week for a 50-day expedition focused on a volcano-driven mass extinction event from our planet’s past.
• The event, 183 million years ago, put enough carbon into the atmosphere to change the planet’s climate and oceans, while destroying a multitude of life forms.
• They say their expedition, in which they expect to encounter extreme polar conditions, could tell us more about the climate change ramifications of human fossil fuel burning today.

Kiwi scientists are venturing into Antarctica’s remote reaches to study a devastating event that wiped out life across Earth – and what they learn could yield important insights into how fossil fuel burning is warming our planet today.

Some 183 million years ago, around the time of the initial break-up of the Gondwana supercontinent, enormous volcanic eruptions and sprawling lava deposits covered large areas of southern Africa and Antarctica.

These major events, forming masses called large igneous provinces (LIPs), are known to occur every 20 million years. The very largest put enough carbon into the atmosphere to change the planet’s climate and oceans, while destroying a multitude of life forms.

That’s just what happened during the time of the “Ferrar” igneous province – the focus of a University of Auckland-led expedition this month – but much about its associated mass extinction event remains unclear.

The project’s leader, Dr James Muirhead, explained his team’s hypothesis.

“As the provinces are formed, vast volumes of magma flow through the upper levels of the Earth’s crust on their way to the surface,” he said.

“Much of that hot magma, however, remains within the crust and heats up the surrounding sedimentary rocks.

“If abundant organic carbon is present within these rocks, we think they essentially burn off and release greenhouse gases, driving global environmental change and mass extinction.”

To test that hypothesis, the team will analyse frozen Ferrar remnants that have been gradually lifted to the surface over tens of millions of years, amid Antarctica’s famous McMurdo Dry Valleys.

That will involve testing how much heat these ancient magmas brought to the surface 183 million years ago, what temperatures they once reached, and just how much carbon was released through them.

Antarctica's transantarctic mountains (pictured) store 183-million-old rocks that will help University of Auckland scientist piece together a prehistoric extinction event. Photo / James Muirhead

Muirhead said the team, who are to fly to New Zealand’s Scott Base this week, expect to encounter extreme cold and high winds amid the mountains, where they’d be working and camping outdoors for about 50 days.

“For about 45 of these days, we’ll be at an elevation of higher than 1500m, so I’d expect typical ambient temperatures to range [from] -10C to -20C – and it can get colder,” he said.

“We can also expect windchill on a number of days to be below -30C, which is too dangerous to work in and will force us to wait in our tents for the weather to clear.”

But such was the effort required to retrieve evidence which Muirhead expected would draw “significant interest” from the scientific community.

“Mass extinctions are critical events that have played an important role in shaping the evolutionary trajectory of life on our planet,” he said.

“Understanding the causes represents a fundamental question in the field of earth sciences.”

Moreover, he said, the work could tell us more about the climate change ramifications of human fossil fuel burning today.

Specifically, they’d investigate whether the crustal carbon released 183 million years ago eventually hit a specific tipping point, driving a catastrophic drop in biodiversity.

“This will allow us to assess whether Earth’s geological record contains case studies, which will help us understand future impacts of anthropogenic greenhouse gas release.”

Jamie Morton is a specialist in science and environmental reporting. He joined the Herald in 2011 and writes about everything from conservation and climate change to natural hazards and new technology.

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