Department of Geography-Geology at Illinois State University
Department of Geography-Geology at Illinois State University
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Geography - Geology News

WWS Geologic Images

Photo 1: Barrel on right sank into the mud while barrel on left did not, over the same time period.

By Bill Shilts

Patterned Ground is the term for the distinctive ornamentations of seasonally thawed  soils in areas of permafrost. In the permafrost areas of Canada, west of Hudson Bay,  one to two meter-diameter, circular patterns, or mudboils, form on glacial sediments that contain significant amounts of clay, silt, and sand. As part of a research program to develop methods of doing mineral exploration in remote areas of arctic Canada, a program of mapping and laboratory study began in this region to define physical and chemical properties of the various sediment types that form mudboils and associated patterned ground. Patterned ground occurs on virtually all glacial and postglacial soils in the eastern District of Keewatin (now the southwestern region of Nunavut Territory, Canada). The purpose of these studies was to ascertain relationships between surface patterns and properties of underlying soil (unconsolidated sediment). The conclusions from the study led to the development of a detailed mapping strategy that helped authorities produce the first detailed maps of the surficial materials in the low arctic environment of southwestern Nunavut. The detailed maps served as the basis for a 1:1,000,000-scale map of the main surficial deposits of the western Canadian Shield.

Atterberg Limits are derived from standard engineering laboratory tests that measure a sediment’s propensity to behave as a solid, plastic substance, or a liquid at varying moisture contents. The Plastic Limit is the moisture content, in weight %, at which an uncemented sediment (“soil” in engineering terms) passes from a solid (non-deformable) to a plastic (deformable) state. The Liquid Limit is the moisture content, in weight % water, at which a plastic sediment passes from a plastic to liquid state, that is, the sediment loses its strength and behaves like a liquid. The Plasticity Index is the range of moisture contents, in weight % water, over which a sediment will behave as a plastic substance and represents the difference between the solid and liquid states, between the plastic and liquid limits.

It is apparent that liquid limits for Keewatin “muddy soils” are very low with respect to other arctic or subarctic “muds” and that plasticity indices are low (<4%) or unmeasurable. This means that at very low moisture contents, Keewatin “muds” pass from a solid state possessing concrete-like strength to a liquid state with virtually no strength, either directly, or after passing through a very minor plastic phase. Thus, a very slight increase in moisture content or an increase in pore-water pressure may cause a seemingly solid soil to liquefy or founder, or, conversely, very slight decrease of these stresses may cause an apparently liquid, soft mud to become solid.

An example of the tendency of glacial muds to liquefy easily in this region is this image, photo 1, of two 10-imperial-gallon barrels, one on a stable, lichen-covered mud (glacial till) surface and the other on an active, lichen-free mud surface by Dr. Tony Davidson of the Geological Survey of Canada in 1968. Over seven years, the nearly empty barrel on the bare part of the mudboil sank, despite its light, less-than-ten-pound weight. This is an example of the effect of low liquid limits on till and fine-grained marine sediments that underlie much of the area. The propensity for sediment in the active (seasonally thawed)  layer in this area of deep permafrost to liquefy, even when lightly loaded, has important ramifications for construction, terrain disturbance, human activity in general, or loading by the hooves of the large, migrating caribou herds that are common in this area.

Another, even more graphic and unsettling example of the peculiar properties of soils with low liquid limits and limited plasticity, occurred in 1973, when Aaron Villakazie, a student assistant, was using a pointed steel bar to map the configuration of the permafrost surface beneath subaqueous patterned ground features near the shoreline of an island in Kaminak Lake (a very large lake, perhaps a third of the size of Lake Ontario). His foot became trapped in the mud as he attempted to pull the bar out of the bottom. As he struggled to free himself, his left foot sank farther and farther until he was waist-deep in water that had been a few inches deep at the start of the incident. Several people, flown to the small island in our helicopter, worked more than two hours, without success, to free him. The cause of his predicament was that, as his foot sank in the saturated mud, his weight, transferred to the mud at the sole of his leather boot, increased the pore water pressure in the mud, causing it to pass above its liquid limit (12.4% water by weight), liquefying it. As his foot descended, the mud above his foot, because of the limited plasticity index of the till in this area (<1%) passed back below the plastic limit and set to concrete-like hardness, preventing him from moving his foot. Fortunately, we had our helicopter with us, and I was able to fly out several assistants from my base camp to the island to help dig him out.  Even though we attempted to excavate the material around his leg, it was not possible to keep the excavated mud from flowing back into the depression and setting up solidly again. Despite the efforts of seven men, Aaron sank almost to the frost table and was extricated only after the rigid sediment around his leg was excavated hydraulically using a portable, high-discharge water pump that we flew to the island from my base camp.

WWS Geologic Images

Photo 2: Research assistant Aaron contemplated removal of probe from lake bottom.

WWS Geologic Images

Photo 3: The author, Bill Shilts, had no success trying to pull Aaron from the mud.

Photo 2 is of the site where Aaron became entrapped; it was taken approximately two hours before the final photo in series. The metal probe is protruding from the bare mud (till) patch in which his foot became entrapped. Photo 3 shows me halfheartedly trying to pull Aaron out because I was exhausted from an hour and a half of snorkeling to map the extent of permafrost in offshore sediments.

Shilts 4

Photo 4: Digging was not helping either.

Photo 4 shows Aaron submerged deeply after he had sunk into the liquefying mud after a two-hour struggle to extricate him. Just after this picture was taken, we flew in the high-discharge firefighting pump to hydraulically blast the mud away from his leg, freeing him. This is an example of the types of challenges that faced me and my colleagues when we worked in this relatively little known area in the early 1970s. I certainly don’t face management problems so unforeseen as this in my present position.


EDITOR’S NOTE: Bill (William Weimer) Shilts is the Founding Executive Director of the Prairie Research Institute, housed on the campus of the University of Illinois at Urbana-Champaign. He included this research tale in his February 2014 presentation in the departmental speaker series.


Las Vegas community2

By RJ Rowley

“Community” is a complex word. Its meanings differ depending on whom you talk to. Even geographers view community in a variety of ways. Most people, however, would agree that everyday, traditional community is something that connotes a sense of unity among a group of people who live within a space or territory. When conjuring up images of community, many of us might think back to the neighborhood we grew up in, where we played night games at the neighborhood churchyard with our friends from the surrounding homes. Or, we imagine a farming community coming together for the harvest or a ranching community for a branding. But urban scholars, including the well-known Jane Jacobs, point to the contemporary city as anti-community, a place where our individual lives and career goals, or the anonymity built into suburban neighborhood design, can make it difficult to recognize the “traditional” community city dwellers often imagine and even long for.

I have explored the ideal of community in my research about Las Vegas and found that southern Nevada is, indeed, reflective of what I call “discommunity.” The three-shift working nature of the city, the gambler mentality held by many local residents, transience in the rapidly growing population, the goal to make it in this fast town, and the proliferation of gated-entry—garage-centered—cinderblock-bounded residential landscapes all contribute to a lack of inherent and natural community in Las Vegas neighborhoods. Rather, I found that community is often in interest groups and a common connection to a city-wide sense of place felt by many residents from throughout the urban area.

Still, in my interviews with and observations of local residents, I encountered some exceptions, which have been noted by other observers, including John L. Smith, a local columnist and one of the city’s keenest observers: “Despite the shift work, and the gambling circuit…you find pockets of community throughout the valley.” I was impressed on one occasion when I observed one such pocket of community in the neighborhood I lived in while conducting research back in 2007.

Countless times, as I came and went in my research activities, I saw Mitch, an elderly gentleman who lived two doors down from my house, out visiting with one or another neighbor in front of their homes. Jane Jacobs probably would call Mitch a “public sidewalk character,” someone who, she wrote, would be an important anchor for “the social structure of sidewalk life” and the community it creates (68). One June day, as I sat working at my desk facing the window’s view of the street, I observed and recorded the following neighborly encounter in my field journal, an encounter that I see as representative of our block:

This summer the Pavlovich family, who recently moved in across the street, is traveling. Anton, the husband and father, is going to China and New York on business and then will join his wife, Hanna, and their daughter who are already in their native Ukraine. He left a key with Mitch to help watch the house, water plants, etc. Their car is covered by a grey tarp. When I came home, their door was open. Our assumption was that Mitch was doing his regular patrol, but I watched to make sure. My assumption was correct. He came outside, turned and locked the door. He checked it to make sure it was locked properly and walked down the driveway toward his home. Coming back to double-check the lock, he finally departed….As he walked across the street, another neighbor rode up his driveway on his scooter. The man waved to Mitch. Mitch waved back. But, this was not the typical Vegas noncommittal wave we locals hear about sometimes. Mitch veered from his course and had a short visit with the returning neighbor in the shade.

Based on conversations about community with locals from throughout the Las Vegas Valley, such an experience is rare. It seems to be less rare, however, in this neighborhood. I visited once with Louise Fishman, who decried the lack of community in her current suburban home, but changed her tone as she explained that my neighborhood is different. (Her father lived in this neighborhood until he passed away, incidentally in the same house now owned by the Pavlovich family.) She remembered the many hands that reached out to help as her father struggled with an illness that eventually took his life: “My dad would not have lived as long as he did if it wouldn’t have been for those people in that neighborhood.”

This all made me wonder what was different about this neighborhood. I’m certain that time has something to do with it. My neighborhood is an older one by Las Vegas standards and Mitch has lived there for decades (a long time to be in the same neighborhood in a transient place like Las Vegas). But, more than that, I think, the impetus for a thriving community is in the “public sidewalk characters” like Mitch, the ones that go outside their homes and comfort zones to “make” community in their neighborhood. Just this month, I was back home and looking out at the same street. I saw Mitch again out in the neighborhood, this time bringing the newspaper from the base of the Pavlovich family’s driveway to their porch, still watching over his neighbors, still building community.


Jacobs, Jane. The Death and Life of Great American Cities. New York: Random House, 1961.


EDITOR’S NOTE: RJ Rowley, in 2013, published his first book on Las Vegas and began his tenure-track journey as an Assistant Professor of Geography at Illinois State.

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Geography & Geology from CASNews

CAS Faculty & Staff Win Excellence Awards
photo of Amy Robillard, Diane Smith, Brenda Huber, Greg Simpson (Dean), Lisya Seloni, Andrew Weeks, Bill Shields, Jonathan Thayne

Amy Robillard, Diane Smith, Brenda Huber, Greg Simpson (Dean), Lisya Seloni, Andrew Weeks, Bill Shields, Jonathan Thayne

Seven College of Arts and Sciences faculty and staff members were presented with College Excellence Awards at the conclusion of the Fall Dean’s Address on September 9. Dr. Amy E. Robillard, Department of English, was the winner of the John A. Dossey Award for Outstanding Teaching, which is presented annually to a tenured faculty member. Dr. Lisya Seloni, Department of English, received the award for Outstanding Teaching by a Pre-tenured Faculty member. Mr. William Shields, Department of Geography-Geology, won the award for Outstanding Teaching by an Administrative Professional. Dr. Andrew Weeks, Department of Languages, Literatures, and Cultures, was the winner of the Janice Witherspoon Neuleib Award for Outstanding Scholarly Achievement. Dr. Jonathan Thayne, won the award for Outstanding Scholarly Achievement by a Pre-tenured Faculty Member. The winner of the award for Outstanding Administrative Professional was Dr. Brenda J. Huber, Department of Psychology. Ms. Diane L. Smith, Graduate Secretary in the Department of English, was the recipient of the Scott M. Elliott Award for Outstanding Civil Service staff. “On behalf of the College of Arts and Sciences, congratulations to all of these award winners,” said Dr. Greg Simpson, Dean of the College. “They represent the very best of the excellent work being done throughout the College of Arts and Sciences.”

Lecture on Tectonism Sept. 5
image of Nathan Niemi

Nathan Niemi

Nathan Niemi will give a talk titled A Paleoelevation History of the Basin and Range and Its Relation to Cenozoic Extensional Tectonism at 3 p.m. Friday, Sept. 5, in 133 Felmley Hall of Science Annex. The talk is free and open to the public.

Niemi’s research interests are in continental deformation, with an emphasis on actively deforming tectonic systems. Niemi, an associate professor of earth and environmental sciences at the University of Michigan, has worked on research dealing with tectonic evolution of northern Tibet.

For more information, contact the Department of Geography-Geology at 438-7649.

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Calendar of Events

Earthquakes, Volcanos, and Storms: The Politics of Natural Disasters
Fri, September 19, 2014 3:00 PM - 4:00 PM Felmley Hall of Science Annex (FSA), 133 - Free and open to the public
The Foreign Mother Tongue
Tue, September 23, 2014 7:00 PM - 8:00 PM Bone Student Center (BON), Old Main - Free and open to the public
Wed, September 24, 2014 11:00 AM - 1:00 PM Felmley Hall of Science Annex (FSA), 209 - Free and open to the public
The Future of Solar Energy
Fri, October 3, 2014 3:00 PM - 4:00 PM Felmley Hall of Science Annex (FSA), 133 - Free and open to the public

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Normal, Il 61790-4400
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