Jules Verne used his passion for science and adventure and talent in vivid storytelling to open a window into dark and mysterious worlds. His research and corresponding words revealed to the world the beauty and wonder of the deep sea in “Twenty Thousand Leagues Under the Sea.” His appetite for discovery offered his readers a view of the core of our planet in “A Journey to the Center of the Earth.”
Like Verne, a team of researchers will rely on their own talents and passion—theirs is permafrost research and frozen ground engineering – to reveal another mysterious world. Thanks to collaborative support and federal funding, the team will gather information to reveal the mysteries that lie within the frozen underground world of Alaska.
The collaborative project, fully named “Forty-Thousand Years of Yedoma: An investigation into the spatial heterogeneity and paleo-history of organic-rich permafrost in Alaska,” was funded by the National Science Foundation. NSF support will allow the University of Alaska Fairbanks, the U.S. Army Cold Regions Research and Engineering Laboratory (CRREL) and the University of Florida to continue their efforts to understand how permafrost forms and how it abides, and what it can tell us about the earth’s past climate.
Credit: Matt Nolan
Pictured is a panoramic view of the CRREL Permafrost Tunnel, excavated in 1963, at 15 meters into the winze.
Investigators plan to capitalize on information made available by construction of a new permafrost tunnel near Fox, AK, which will make unique and vital paleo-climatic data available. The project promises to feed the hunger for discovery of hidden worlds just as Verne’s work did more than 140 years ago.
The U.S. Army excavated a permafrost tunnel near Fox in 1963. The endeavor has produced vast amounts of data—more than 70 technical papers, hosting researchers from dozens of countries and more than 30 institutions—and offered tremendous outreach and public education opportunities. The tunnel has been the focal point of permafrost research for nearly five decades. Time and exposure have taken a toll on the material of the old walls, however; the new tunnel will expose new frozen ground structures, for new studies. The Department of Defense has funded a project to dig a new tunnel, adjacent to and connected to the old one, and the recently-awarded NSF funds will allow investigators to conduct research while excavation of the new tunnel is taking place.
“It is very important to start our study immediately after the excavation while the walls of the tunnel are in a perfect condition (not affected by contamination and sublimation of ground ice),” project team member Mikhail Kanevskiy of the Institute of Northern Engineering said. “After several months, significant efforts will be required for cleaning the tunnel.”
According to the project team, led by principal investigator Matthew Sturm of CRREL, there are four reasons the research must be conducted concurrent to tunnel excavation:
- To ensure appropriate sampling, not just for reconstructing prehistoric data and carbon and ice research, but also for future studies on Pleistocene fauna and prehistoric DNA;
- To ensure that sample location, documentation and preservation is done correctly;
- To allow day-to-day findings to guide the excavation, similar to the way a miner might follow an ore vein;
- And to fully leverage the excitement and news interest in the project so that education and outreach activities reach the widest segment of the public as possible.
Why does permafrost matter?
Permafrost underlies a quarter of the land area of the Northern Hemisphere. That vast body of frozen ground, which equals approximately 23 million square kilometers, is threatened by accelerated warming, particularly in the Arctic. Scientists now say the question is not whether permafrost change will occur, but by how much, where and with what impact. According to the team of yedoma researchers, degradation of permafrost poses three major risks:
- It alters the surface and subsurface hydrology, often changing surface topography and vegetation, which can in turn further accelerate thawing.
- It releases vast stores of carbon froze in cold storage, known as deep carbon.
- It threatens human infrastructure because thawing ice-rich permafrost leads to surface settlement and collapse.
Engineers often consider Yedoma, organic-rich layers of frozen silt deposits, the most problematic type of permafrost. Because of the high ice content, such deposits are particularly prone to thaw slumping, settlement and collapse, which often mean dramatic changes in the overlying topography. Yedoma covers a million square kilometers across Siberia, Alaska and Canada. Because yedoma tends to be rich in organic material, it is also a major source of deep carbon and an excellent cold storage for paleo- or prehistoric materials, which are useful in dating and climatic reconstructions.
Pictured is a cross section of the CRREL Permafrost Tunnel.
Tunnel me this
Sturm from CRREL, and Shur and Kanevskiy from UAF are joined by Kevin Bjella and Tom Douglas of CRREL; James Beget and Nancy Bigelow of UAF; and Edward Schuur of the University of Florida on the project. The group aims to address three research questions:
- What processes and conditions led to the widespread development of yedoma in the Arctic and why does it contain so much ancient carbon?
- How will this permafrost respond to warming and in what situations will it degrade?
- If the permafrost degrades, what will the consequences be in terms of carbon emissions, changes in local geomorphology and surface subsidence?
Construction of the new permafrost tunnel is key to answering these questions. The yedoma in the tunnel is typical of deposits throughout central and northern Alaska but unlike deposits further north, because sub-arctic Alaska is at greater risk of warming. Permafrost in this area is warm enough that any change in surface conditions, be it fire, construction work, farming or mining, leads to degradation. Whatever is going to happen to yedoma worldwide under warming conditions will happen first in sub-Arctic Alaska near Fairbanks. It is, then, in a sense, “the canary in the coal mine.”
Understanding the resilience of this local yedoma holds the key to anticipating future changes in more stable yedoma elsewhere. To do this, Sturm, Shur, Kanevskiy and their team will first reconstruct the paleo-history of the permafrost and its surrounding environment, building a story of change that spans from more than 40,000 years ago to present. They will pay special attention to the permafrost features during transition from cold to warmer eras, evidence of which can be seen in the tunnel.
“Cryogenic structure and organic matter preserved in permafrost are very important for reconstruction of geological history and conditions of permafrost formation,” Kanevksiy said.
Shur, Sturm, Kanevskiy and Bjella are in charge of creating a three-dimensional map of the large block of yedoma surrounding the tunnel. Yedoma exhibits extreme vertical and horizontal heterogeneity, revealing much about sedimentary structures and ice features, but has never before been mapped. Again, we can picture how Verne’s readers felt when his words mapped the deep sea for them: These new images of the permafrost will greatly expand existing knowledge of the landscape.
The cryogenic structure of frozen ice is the makeup of pore ice, ice lenses of segregated ice and bodies of massive ice within the soil, Kanevksiy explained. The study of cryostructures – ¬patterns created by pore ice and lenses of segregated ice— plays a vital role in understanding the nature of permafrost because these patterns reflect permafrost formation and conditions of freezing.
“Our experience in cryostructure analysis was crucial in the understanding of permafrost formation and later modifications in the existing CRREL permafrost tunnel,” he said.
Cryostratigraphic mapping of the walls and ceiling of the new tunnel will provide detailed information on the permafrost structure in the new tunnel, which will be used as a background for the future work of other researchers such as paleontologists, biologists and mining engineers. By studying organic matter – peat, roots, wood and bones—within the permafrost layers, the team will gain an understanding of the environment during permafrost formation.
“As a result of our study, we will have a clear idea about the time of yedoma formation and sedimentation rates,” Kanevskiy said.
Team members noted the main advantage of the new tunnel, in comparison with natural permafrost exposures, is its stability: The lifespan of natural exposures generally lasts only a few years, while this tunnel will provide access to the same permafrost sequence for many years to come.
“Frozen cores (collected during drilling on the site) along with the data from the new tunnel will help us to characterize the whole yedoma section,” Kanevskiy said.
Tunnel as textbook
Outreach is a key focus of the yedoma project as well. The first CRREL permafrost tunnel has appeared in more than 20 documentaries and has been a learning destination for students K-12 for decades. Hoping to offer learning opportunities to the pool of 15,000 K-12 students in the Fairbanks area, project plans include creating kid-friendly informative displays in the existing visitor center near the tunnel; display a world-class collection of Pleistocene remains of mammoth, steppe bison and other mega-fauna bones that students can handle while learning about the ice ages; add a glass-front walk-in freezer in which real ice cores and ice wedge sections can be viewed, touched and handled by students; and create video displays with permafrost slide shows including ones that illustrate how permafrost thaws and thermokarst occurs.
“The existing permafrost tunnel has provided a unique opportunity for outreach and education. Thousands of people have become introduced to permafrost in that tunnel,” Kanevskiy said. “The new tunnel will provide additional opportunities to learn about permafrost features, paleontology, and geological history of interior Alaska.”
He added that work in the new tunnel “will allow to students to participate in the exciting work of uncovering the history of permafrost formation and the environmental conditions of that time.”
