Miller

Sediment records provide a glimpse into Iceland’s past, and hope for its future

Gabe Allen — Tue, 13 May 2025 21:38:08 +0000

Sediment records provide a glimpse into Iceland’s past, and hope for its future Gabe Allen Tue, 05/13/2025 - 15:38

Gabe Allen

Just a couple of kilometers inland from the coast of Northern Iceland, lie Torfdalsvatn, a small, deep freshwater lake. Winters here are frigid, snowy and dark, save a few hours of muted daylight. Lucky visitors might catch a glimpse of the Northern Lights when the clouds clear.

Most travelers opt to visit the region in the summer, when conditions are more temperate, but for paleoclimate researchers, winter is the perfect time for a trip to Torfdalsvatn. That’s because the mud that lies below the lake holds an exceptionally detailed record of Earth’s past. And, in the winter, researchers can bring the cumbersome equipment needed to drill down into the mud right out on the ice with them.

“You can drive right out onto the ice and drill through with an ice auger,” CIRES research scientist and INSTAAR affiliate David Harning explained. “It’s much harder in the summer when you’re out in a little boat trying to anchor it and it’s windy and our boat is getting dumped on.”

Last month, Harning, along with American and Icelandic collaborators, published a new analysis built on decades of research at Torfdalsvatn. The study brings diverse analytical methods together to provide a highly detailed picture of past climatic conditions, soil stability and plant life at the site.

One clear takeaway was that Torfdalsvatn’s soils and plant communities remained exceptionally resilient, when compared to other sites in Iceland. It’s an insight that is more than a piece of history—it could help conservationists better plan for the future.

“Soil erosion is one of the biggest problems in Iceland right now,” Harning said. “Understanding the resilience or fragility of certain areas to future changes in soil erosion is really important to conserving these landscapes.”

Fire and ice in the mud

Since 1992, researchers have looked to the sediments below Torfadalsvatn to understand the past 12,000 years of climatic conditions in Iceland. The site is an exceptionally good model of the past for two reasons.

Firstly, sediment piles up at the bottom of Torfadalsvatn at an unusually high clip, leaving researchers more mud to analyze. Secondly, Torfadalsvatn was one of the first lakes to emerge, when the giant ice sheet that once stretched across Iceland began to retreat 12,000 years ago. As a result, the lakebed houses some of the oldest sediment in the country.

The winter 2020 field team operates a sediment coring device on a clear day. Left to right: Jonathan Raberg (Postdoc, University of Wyoming and former INSTAAR PhD), Gifford Miller, and Áslaug Geirsdóttir. Photo courtesy of David Harning.

Over the past three decades, much of the work on Torfadalsvatn’s sediment record has been done by two researchers and their students: INSTAAR faculty fellow Gifford Miller and University of Iceland professor of geology Áslaug Geirsdóttir.

Harning, a former student of both, was brought in on the project during his PhD studies at INSTAAR. Between other projects, he worked to identify layers of volcanic ash in the sediment (Iceland is known as “the land of fire and ice” because of its plentiful active volcanoes).

Over the lifetime of the project, several other researchers devoted countless hours to other analyses. These included identifying algal pigments and geochemical markers, proxies for past plant communities and climate respectively.

In the new study, Harning pairs these previous analyses with a suite of techniques meant to place each data point more precisely in time.

Áslaug Geirsdóttir prepares the sediment coring device at Torfdalsvatn. Due to the lake’s high sedimentation rates, this 3 meter long tube will only recover around 3,000 years of mud. Multiple subsequent cores are then required to collect the entire 12,000 year history. Photo courtesy of David Harning.

“By establishing the chronology and locking sedimentary history in time, we could start to ask some of these longstanding questions that our group has been interested in,” he said.

One of these questions, perhaps the most controversial one, concerns soil erosion and human settlement. There is a longstanding theory that Norse settlers caused widespread soil erosion and ecological degradation when they arrived in Iceland a millenia ago. Recent research has called this narrative into question, suggesting that these changes could have been kicked off by environmental changes even further in the past.

Harning’s analysis, though, complicates the theory even further. The researchers estimated that erosion and vegetation changes at Torfadalsvatn didn’t escalate until around 200 years after the arrival of settlers. Perhaps something about the site made it more resistant to whatever factors caused degradation elsewhere.

“We weren’t expecting that,” Harning said. “This implied that the site, which is coastal and at a low elevation, had some sort of natural resilience to the processes that were causing soil erosion elsewhere.”

Looking Forward

Harning urges that further research should look into what made Torfadalsvatn so resilient. The question is still relevant today, as Icelandic land managers and farmers search for ways to combat soil erosion and deforestation on the landscape.

Harning and his colleagues’ recent paper could also provide useful information for other scientific fields. The analysis provides an exceptionally detailed record of past volcanic events, many of which had not been previously identified. If corroborated, these markers could provide, essentially, a time stamp in the sediment record to aid future research.

“It’s a ton of information about volcanic history,” Harning said. “Maybe someone else finds another link, and then you have new marker layers.”

Finally, the new analysis provides a huge amount of information relating past climatic conditions to ecological conditions. This information isn’t only useful for researchers curious about ancient history, it could also help scientists look to the future.

“These high resolution records are a key data constraint for any Earth system model that’s trying to predict future climate change,” Harning said. “If you have a good understanding of the physics of the system, you can run that model forward.”

A new investigation, led by INSTAAR affiliate David Harning, uncovers a story of ecosystem resilience at a lake in coastal Iceland. The analysis could aid future conservation and climate modeling efforts.

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INSTAAR and University of Iceland researchers extracting a sediment core from an Icelandic lake in February 2020. Photo courtesy of David Harning.

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INSTAAR and University of Iceland researchers extracting a sediment core from an Icelandic lake in February 2020. Photo courtesy of David Harning.

This monstrous mama laid the world’s largest egg (National Geographic)

David J Lubinski — Wed, 02 Apr 2025 21:55:03 +0000

This monstrous mama laid the world’s largest egg (National Geographic) David J Lubinski Wed, 04/02/2025 - 15:55

Gifford Miller has studied the fossilized eggshells of the elephant bird Aepyornis maximus and comments on how human predation may have contributed to their extinction.

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Kirk Bryan Award goes to a team of INSTAARs, colleagues

Anonymous — Thu, 19 Oct 2023 21:34:00 +0000

Kirk Bryan Award goes to a team of INSTAARs, colleagues Anonymous (not verified) Thu, 10/19/2023 - 15:34

Shelly Sommer

A team of researchers that included several INSTAAR scientists received the prestigious Kirk Bryan Award from the Quaternary Geology & Geomorphology Division of the Geological Society of America (GSA). The prestigious award honors the authors of a recent paper that advances the science of geomorphology.

Led by former INSTAAR PhD student Simon Pendleton, now an Assistant Professor of Practice at Plymouth State University, the team of researchers included INSTAARs Gifford Miller, Scott Lehman, Sarah Crump, and Robert S. Anderson and colleagues Nathaniel Lifton from Purdue University and John Southon from the University of California, Irvine.

Their paper in Nature Communications, “Rapidly receding Arctic Canada glaciers revealing landscapes continuously ice-covered for more than 40,000 years,” was published in 2019. The study looked at the ages of ancient plants preserved by now-receding ice caps in Arctic Canada. It found that the summer warmth of the past century now exceeds any century in within the past 115,000 years. In an acceptance speech at the GSA annual meeting, Pendleton described a long and collaborative process that led to the paper’s publication, involving, “the chance collection of preserved plants nearly 60 years ago, some not insignificant improvements in radiocarbon dating, the invention of an entirely new surface dating technique (cosmogenic exposure dating), and the perseverance of individuals in the pursuit of understanding these landscapes and the climate secrets they hold.” The researchers spent hours walking ice margins on Baffin Island and processed hundreds of preserved plants in labs to date the plants and place them in a context stretching for thousands of years. He added, “In many ways, this paper encapsulates the theme of the Kirk Bryan award: the innovations made by others over past decades enabled our team to continue to advance the field and our understanding of these glacier-climate systems.”

“It was only recently that I fully appreciated the irony of this particular project,” said Pendleton. “The irony that the warming of the climate—the very thing we are attempting to quantify and characterize—is revealing to us, through ice recession, the data we need to do it. These newly exposed materials are ephemeral, and once they are gone, the record is lost forever.”

The award comes with a monetary prize, which the authors will donate to the Sarah Crump Graduate Fellowship. Sarah Crump was an author on the paper who contributed significantly to the field and lab portions of the study. She passed away in 2022 after a battle with cancer, leaving a legacy of outstanding paleoclimate science paired with a strong commitment to inclusion and community building.

Previous Kirk Bryan Award winners from the University of Colorado Boulder include John Andrews in 1973 and Peter Birkeland in 1988.

Simon Pendleton and Giff Miller collect ancient plant remains melted out of the edge of an ice cap on Baffin Island. Photo by Matt Kennedy, Earth Vision Trust.

Giff Miller holds a clump of ancient moss, recently melted out of the edge of an ice cap on Baffin Island. Photo by Matthew Kennedy, Earth Vision Trust.

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How 1,200-year-old eggs from a 9-foot tall, 1,500-pound bird led to a scientific breakthrough (USA Today)

Anonymous — Sat, 11 Mar 2023 07:00:00 +0000

How 1,200-year-old eggs from a 9-foot tall, 1,500-pound bird led to a scientific breakthrough (USA Today) Anonymous (not verified) Sat, 03/11/2023 - 00:00

Saleen Martin , USA Today

Towering over nine feet tall and weighing over 1,500 pounds, the now-extinct aepyornis lived more than 1,200 years ago and was Madagascar’s largest land animal. Scientists at the University of Colorado Boulder and Curtin University in Australia recently discovered a new lineage of the birds using eggshell remnants, as well as isotope geochemistry and protein extraction. The findings were published in Nature Communications.

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Giant eggshells reveal the secrets of Madagascar's elephant birds (NPR)

Anonymous — Wed, 08 Mar 2023 18:44:26 +0000

Giant eggshells reveal the secrets of Madagascar's elephant birds (NPR) Anonymous (not verified) Wed, 03/08/2023 - 11:44

Before they were driven to extinction, giant elephant birds roamed Madagascar, weighing up to 2,000 pounds and towering 10 feet tall. A new analysis of DNA in their eggshells gives new information about the birds and identifies a previously unknown lineage. The story is a 2-minute listen on National Public Radio.

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Ancient eggshells unlock discovery of extinct elephant bird lineage (С�� Boulder Today)

Anonymous — Wed, 01 Mar 2023 18:29:40 +0000

Ancient eggshells unlock discovery of extinct elephant bird lineage (С�� Boulder Today) Anonymous (not verified) Wed, 03/01/2023 - 11:29

Kelsey Simpkins , С��

More than 1,200 years ago, elephant birds roamed the island of Madagascar. While these ostrich-like giants are now extinct, new research from С�� Boulder and Curtin University in Australia reveals that their eggshell remnants hold valuable clues about their time on Earth. Published today in Nature Communications, the study describes the discovery of a previously unknown, separate lineage of elephant bird that roamed the wet, forested landscapes on the northeastern side of Madagascar—a discovery made without access to any skeletal remains.

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How we cracked the mystery of Australia’s prehistoric giant eggs (The Conversation)

Anonymous — Wed, 25 Jan 2023 23:30:01 +0000

How we cracked the mystery of Australia’s prehistoric giant eggs (The Conversation) Anonymous (not verified) Wed, 01/25/2023 - 16:30

Gifford Miller and collaborators Matthew James Collins and Beatrice Demarchi tell the story of the ancient eggshell fragments found in eroding Australian sand dunes, the controversy around their origins, and how new techniques and AI helped solve the mystery. A summary chapter in the evolving story of Genyornis and the probable causes of its extinction.

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Egg-eating humans helped drive Australia’s ‘thunder bird’ to extinction (Science)

Anonymous — Fri, 27 May 2022 06:00:00 +0000

Egg-eating humans helped drive Australia’s ‘thunder bird’ to extinction (Science) Anonymous (not verified) Fri, 05/27/2022 - 00:00

The giant bird Genyornis newtoni disappeared from Australia 45,000 years ago, and researchers have long puzzled over whether human hunters or climate change was the culprit. Now, a new analysis of ancient eggshells—the leftovers of a prehistoric feast—suggests humans were responsible. Study led by Giff Miller. Illustration by Nobu Tamura.

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Bits of an extinct bird’s eggshells may be clue to why megafauna vanished (Washington Post)

Anonymous — Thu, 26 May 2022 06:00:00 +0000

Bits of an extinct bird’s eggshells may be clue to why megafauna vanished (Washington Post) Anonymous (not verified) Thu, 05/26/2022 - 00:00

A new study led by Giff Miller suggests that the 500-pound <em>Genyornis newtoni<em> laid the eggs marked by cooking fires in Australia, and not a smaller bird. The study could shed light on an even bigger scientific mystery, of why megafauna went extinct shortly after the advent of humans on the continent.

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New class of С�� Distinguished Professors: Leaders in research, education, service (С�� Connections)

Anonymous — Thu, 11 Nov 2021 07:00:00 +0000

New class of С�� Distinguished Professors: Leaders in research, education, service (С�� Connections) Anonymous (not verified) Thu, 11/11/2021 - 00:00

University’s highest faculty honor awarded to 11 professors for 2021, including INSTAARs Diane McKnight and Giff Miller.

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Miller

Sediment records provide a glimpse into Iceland’s past, and hope for its future

Fire and ice in the mud

Looking Forward

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