Aging Ice-Cored Moraines in the Canadian Arctic

Baffin Island in Nunavut, Canada, has served as the backdrop for dozens of investigations into glaciation and ice-age patterns. Now a new paper takes a unique look at assigning ages to some of the oldest moraines from the most recent episode of glacier expansion in the Canadian Arctic.

Sarah Crump, the lead author of the paper, sampling a boulder on the Throne Moraine (Source: P. Thom Davis).

Moraines, ridges of debris deposited alongside or in front of a glacier, can contain valuable data for understanding past climate. The positions of these debris are controlled by temperature and precipitation, which when combined with moraine dating can help construct a picture of past glacier margins. Ice-cored moraines fronting debris-covered glaciers, like the ones this paper investigated, are formed when glaciers with debris on them, like rocks and sediment, retreat and leave behind sections of debris-covered ice. Over time, that ice slowly melts— and its melt-rate is affected (often further slowed) by all the debris that cover and protect the ice from solar radiation. These ice-cored moraines, named because they are moraines with remnants of glacial ice, are notoriously difficult to study because there are many factors that influence how accurately they can be dated. Fully extrapolating the glaciers’ positions and age from the ice-cored moraines also depends on the long history of temperature and precipitation in the area, which contributes to glacier formation and melting. However, when all these factors are accounted for, the positions of these debris can show the location of past glacier margins, reflecting the size of glaciers in the past.  

The researcher’s base camp near Spire and Throne glaciers (Source: Sarah Crump).

To date the moraines, the researchers examine the concentration of a beryllium isotope, 10Be, that accumulates only in some minerals (like quartz) in the uppermost layers of rocks. The rate of accumulation is well understood and based on cosmic ray interactions in the atmosphere and within the rock itself. Since only rocks on the earth’s surface accumulate 10Be, researchers can calculate how long that rock was exposed on the earth’s surface by comparing the concentrations of isolating a sample of 10Be in a rock from a moraine to other well-dated rocks. GlacierHub spoke with Sarah Crump, the lead author on this paper, who explained that with this information “we can estimate when a glacier was extended to the location of the moraine, and thereby make inferences about climate at the time.” Using this data, they reported that the moraines likely formed5,200 to 3,500 years ago during the Neoglaciation of the Late Holocene.  

However, 10Be dating has some uncertainty. Crump and her team realized that because “the 10Be ages exhibited quite a bit of spread,” they needed to take a closer look at the glacial setting and mechanics of moraine formation. “We thus teamed up with co-author Leif Anderson to collect glaciological data at the field sites and model a simplified, representative debris-covered glacier,” she said. Additionally, they used field observations of the moraines to decipher if the debris had evolved since their initial formation. The researchers looked for evidence of morphological changes caused by uneven ice melting over time, or moraine degradation leading to surface boulders to roll and new boulder faces to emerge— all of which can affect 10Be dates. The results of the paper combine findings from these three methods: 10Be dating (or more formally cosmogenic radionuclide dating), numerical modeling based on field collected glaciological data, and field observations for moraine evolution.

Due to this collaboration and methodology, this study is unique. Michael Kaplan, a paleoclimatologist at Columbia University, commented on the novelty of this research: “I am not familiar with another paper that uses these three approaches (and the different respective experts as coauthors) in the manner that Crump et al. do.”

The field team setting up a meteorological station on Spire Glacier (Source: Sarah Crump).

Though this combination of methods is novel, Crump stated that there are still some uncertainties in the precise formation age of the moraines. Often, 10Be dating results can deliver ages that are either older or younger than the actual age of the moraines. For example, rocks and boulders that ended up on a moraine might have arrived before glacial erosion, which would result in an age that was too old. The other two methods— field observations and numerical modeling— helped inform their final conclusions and significantly reduced uncertainty (though some uncertainty inherent to 10Be dating can never be completely eliminated).

Overall, Crump hopes that “readers will take note of the very important role of debris in glacier systems, both in terms of how they respond to climate variability and in terms of their geomorphic effect on the landscape.” These results show the importance of taking into account the glacial setting and help to clarify and identify some of the uncertainty around the moraine record, giving a deeper understanding of the relationship between glacier fluctuation and climate variability, allowing researchers to gather more detailed and accurate information about past climates and therefore better assess the future.

If you’re interested in learning more about the area, Gifford Miller, a co-author of the paper has an informative video about Baffin Island and its importance.

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Roundup: A Glacier Bus, Andean Rivers, and Ice-Cored Moraines

The Glacier Bus Turning Heads

From Iceland Monitor: “Glacier bus Sleipnir, named after Odin’s eight-legged-horse in Norse mythology, is the largest such truck in the world. It features eight wheels and is currently being tested on Langjökull Glacier where it passes with flying colors. It features comfortable leather seats inside for passengers with views to both sides of the vehicle and through the roof. The vehicle cost around 70 million ISK to make and it can cross glacial crevasses measuring up to three meters.”

Read more about Sleipnir’s big wheels here.

The Sleipnir, the largest bus in the world (Source: Hotel Husafell/Twitter).

 

Determining Distribution of Insects in Andean Rivers

From Ecohydrology: “This research was conducted in the high-Andean basin of the Zhurucay River in southern Ecuador. In 4 river reaches, 19 sampling campaigns were conducted per reach spread over a period of 35 months. The biotic samples were selected in the periods with greatest flow stability… In conclusion, although macroinvertebrates are currently employed in water quality studies, riparian vegetation and hydromorphological factors are determinant for their communities in pristine Andean rivers. Such factors are therefore crucial in the study of environmental flows and the assessment of the ecological integrity.”

Learn more about what influences the distribution of insects in glacier streams in Ecuador here.

The Zhurucay River Ecohydrological Observatory (Source: Mario Cordova/blogs-mri.org)

 

Interpreting Exposure Ages from Ice-Cored Moraines

From Journal of Quaternary Science: “Be dating of moraines has greatly improved our ability to constrain the timing of past glaciations and thus past cold events… Here we present 28 new Be ages from ice-cored Neoglacial moraines on Baffin Island, Arctic Canada, and explore the processes at play in moraine formation and evolution through field observations and a numerical debris-covered glacier model… Three Baffin Island moraines yield Be ages suggesting formation at 5.2, 4.6 and 3.5 ka, respectively, adding to a growing body of evidence for significant summer cooling millennia before the Little Ice Age.”

Read more about the study on Baffin Island here.

The snow and ice of Baffin Island, Canada (Source: Stuart Rankin/Flickr).

 

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Indigenous Art Promotes Resilience to Climate Change

Uqqurmiut Centre for Arts and Crafts, Pangnirtung (source: Timothy K/Panoramio)
Uqqurmiut Centre for Arts and Crafts, Pangnirtung (source: Timothy K/Panoramio)

Indigenous art can play a role in transmitting environmental knowledge between generations and across cultures, according to an article published recently in the journal Ecology and Society. Inuit people in northern Canada produce art that conveys their perceptions of environmental change to younger generations within their community and to the wider world

Authors Kaitlyn Rathwell and Derek Armitage interviewed 30 professional artists in the towns of  Pangnirtung and Cape Dorset, both towns in Baffin Island in northern Canada where the decline of sea ice and changing seasons impact traditional hunting and food security. They selected the towns, both former trading posts for the Hudson Bay Company, for their “legacy of artmaking,” including textiles, carving, and printmaking. Cape Dorset is known as the “Capital of Inuit Art,” and carvers there use power tools on their work. The authors wrote, “While walking the streets, one hears the soundtrack of power tools omnipresent as carvers work constantly beside houses.” Local art cooperatives purchase the work and showcase it in national and international markets.

Hudson's Bay Company blubber station at Pangnirtung (source: Slp1/Creative Commons)
Hudson’s Bay Company blubber station at Pangnirtung (source: Slp1/Creative Commons)

Among professional artists, the artwork is an important source of livelihood. Newer generations of Innit are relying on art for income generation in areas where work opportunities are otherwise limited to commercial fishing and local social services.  International market demands, such as the unacceptability of seal skin canvases in European markets, have shifted the type of work that the Inuit produce.

Rathwell and Armitage also undertook a series of activities that led to the creation of a mural. They opened with a planning process to learn local priorities and build local support. These led to a full-day workshop, in which Inuit youth and youth from southern Canada discussed old and new times and sketched vignettes, which the group then integrated into a sketch for a mural. At a later workshop, they presented the mural to a group of elders, who then had a storytelling session about sea ice. The youth made sketches during this session. These activities overlapped with more formal art-making at a print shop and a studio.

Mural produced by Inuit artists in Pangnirtung, Nunavut, Canada (source: Ecology and Society)
Mural produced by Inuit artists in Pangnirtung, Nunavut, Canada (source: Ecology and Society)

Based on their interviews and observations of the workshops, the authors describe how knowledge is shared and recreated through art and art-making. The authors identify mechanisms by which art transmits and fosters knowledge. Firstly, artist embed messages and meanings in the objects they create. The artist Elisapee Ishulutaq stated, “When I was young the ice was not dangerous…now it’s getting dangerous and through art, artists can get [that message] out there.” Another mechanism was the sharing of knowledge through art, particularly across generations. The artist Toonoo Sharky said, “I learned by watching my grandfather and I took his place trying to imitate his carving at that time”

The authors find that the art-making provides a context that bring together the environmental knowledge of the elders and the skills of artists of different generations. One artist, Eddie Perrier, described how one printmaker, Jolly, taught him specific techniques while another, Eena, provided environmental knowledge. He said, “Jolly showed me how to draw icebergs and the mountains [from] his perspective.… she [Eena] is a really talented artist and printmaker and she is the one who told me the stories about…the snow on the mountains and about how the glaciers are changing. Where Jolly was just showing me how to draw it, not the story behind it.”

Andrew Qappak, Favourite Place to Be, 1987 (source: Inuit Art Quarterly)
Andrew Qappik, Favourite Place to Be, 1987 (source: Inuit Art Quarterly)

Another artist, Andrew Qappik, described recently making a “a large watercolor painting a couple weeks ago at the print shop. Painted the fjord where there use to be a lot of glaciers [and] now the glaciers are not there as much as they used to be. That is what I believe I’m showing in the painting.”  

The authors conclude that Inuit in both communities use art to provide livelihoods and to strengthen their communities. They show that the process of making art itself reinforces social ties and cultural understandings. Moreover, the techniques used in the art support not only the production of items for sale, but also maintain the traditional crafts, such as kamik or hand-sewn sealskin boots, which are used on hunting trips. In these ways, the art contributes to the resilience of an indigenous culture in a changing environment.

To see a video about Andrew Qappik from the National Film Board of Canada, click here.

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