The work of John Bluemle PhD

Wells

12-DEAD-ICE MORAINE

North Dakota, physiographic map, geology

Fig. 12-A. Physiographic map showing the distribution of the landform regions in North Dakota. The main areas of dead-ice moraine are the Missouri Coteau, Turtle Mountain, and the Prairie Coteau. Diagram: 1-29-2015

Geologists tend to concoct unusual names for the things they study. “Dead-ice moraine” may sound odd to some of you. It’s a name for a kind of landform found in parts of North Dakota. Dead-ice moraine sounds odd enough, but can you believe it is found along with things called “doughnuts” and “puckered lips”? First of all, the word “moraine” is an 18th century French word. It was coined by Horace de Saussure to refer to “a heap of earth or stony debris” (de Saussure did not initially realize he was referring to glacial deposits).  I’ll explain the “dead” part of dead-ice moraine later.

North Dakota, geology, Mountrail Co., dead ice topography

Fig. 12-B. Photo of dead-ice moraine topography on the Missouri Coteau in Mountrail County, about five miles north of Palermo. The view is to the west. The road helps to show the irregularity in the landscape. Photo: 7 – 2 – 2010.

 

 

 

Dead-ice moraine is also referred to as “hummocky collapsed glacial topography” or “stagnation moraine.” It has irregular topography,  formed as the last glaciers were melting at the end of the Ice Age, between about 12,000 and 9,000 years ago. The most extensive area of dead-ice moraine in North Dakota is found on the Missouri Coteau, which extends from the northwest corner to the south-central part of the state (coteau is French for “little hill”) Other extensive areas of dead-ice moraine are Turtle Mountain in north-central North Dakota and the Prairie Coteau in the southeast corner of the state near Lidgerwood. All three areas are uplands that stand above the nearby lower land. The landforms on Turtle Mountain are identical to those on the Missouri Coteau and Prairie Coteau, but Turtle Mountain has a woodland cover, the result of several inches more annual precipitation than the other areas.

dead-ice moraine, Wells Co., geology, North Dakota

Fig. 12-C. Dead-ice moraine on the Missouri Coteau near Otis about three miles southeast of Ruso in McLean County. Photo: 6-20-2009.

North Dakota’s areas of dead-ice moraine generally make for poor farmland as they are rough and bouldery. They do, however, include a lot of excellent rangeland and thousands of depressions, which may contain lakes, ponds, and sloughs known as prairie potholes . The dead-ice moraine of the Missouri Coteau is known as the prairie-pothole region (the so-called North Dakota “duck factory”). The dead-ice moraine is essentially undrained, except locally. No rivers or streams flow  for any appreciable distance in any of the three dead-ice regions – Turtle Mountain, the Missouri Coteau, or the Prairie Coteau. Dead-ice moraine formed when glaciers advanced against and over steep escarpments as they flowed onto the three upland areas. The land rises as much as 650 feet in little more than a mile along parts of the Missouri Escarpment, which marks the eastern and northeastern edge of the Missouri Coteau. Similar prominent escarpments border the Prairie Coteau and Turtle Mountain in North Dakota and Manitoba, especially the west side of Turtle Mountain near Carbury. When the glaciers advanced over these escarpments, the internal stress resulted in shearing in the ice. The shearing brought large amounts of rock and sediment from beneath the glacier into the ice and to its surface.

Bottineau Co., Turtle Mountain, North Dakota, geology

Fig. 12-D. Dead-ice moraine, about four miles west of Lake Metigoshe, Turtle Mountain, Bottineau County. The topography here is essentially the same as that on the Missouri Coteau, but because the area receives several more inches annual precipitation, it is wooded. Photo: 6-30-2010.

geology, North Dakota, Hurdsfield, dead-ice moraine

Fig. 12-E. Dead-ice moraine on the Missouri Coteau, six miles south of Hurdsfield, Wells County. The crop-duster airplane is spraying for weeds. Photo: 8/25/2009.

 

 

 

 

 

 

 

 

 

 

Eventually, as the Ice Age climate moderated, the glaciers became thinner and could no longer flow over higher land, although they kept flowing through lower areas. When the ice on the uplands became detached from still-flowing ice, the glaciers on the uplands stopped advancing and stagnated (or “died”). As the stagnant glacial ice melted, large amounts of sediment that had been dispersed through the ice gradually accumulated on top of the ice, which was several hundred feet thick. The thick covering of sediment on the stagnant glacier helped to insulate the underlying ice, helping to preserve it and prolonging the time it took to melt. As a result, it took several thousand years for the ice to melt. Geologists have determined that insulated, stagnant glacial ice continued to exist on the Turtle Mountain and Missouri Coteau uplands until about 9,000 years ago, nearly 3,000 years after actively moving glaciers had disappeared from North Dakota.

Fig. 12-F. When glaciers advanced onto upland areas such as the Missouri Coteau, the resistance to ice flow that resulted when the glacier edge was forced upward as it pushed onto the upland barrier caused large amounts of subglacial material to be forced into the moving ice. After the glacier on the uplands stopped moving (stagnated), and the ice began to melt, the debris that had been incorporated in the ice remained there. As the ice melted, the debris it contained gradually built up top of the melting stagnant glacier. This resulted in an effective layer of insulation, which greatly slowed the rate at which the remaining ice melted. Diagram: 1-29-2015

Fig. 12-F. When glaciers advanced onto upland areas such as the Missouri Coteau, the resistance to ice flow that resulted when the glacier edge was forced upward as it pushed onto the upland barrier caused large amounts of subglacial material to be forced into the moving ice. After the glacier on the uplands stopped moving (stagnated), and the ice began to melt, the debris that had been incorporated in the ice remained there. As the ice melted, the debris it contained gradually built up top of the melting stagnant glacier. This resulted in an effective layer of insulation, which greatly slowed the rate at which the remaining ice melted. Diagram: 1-29-2015

In places where the debris on top of the ice was thickest, the glacier was slowest to melt. If little or no insulating debris covered the glacial ice, melting was quicker and the ice had entirely melted away by 12,000 years ago.

glacial "donut" formation, North Dakota, geology

Fig. 12-HA. Formation of a “doughnut.” Three stages in the development of a “doughnut” in dead-ice moraine. Sediment fills a hole in the low ice (but ice exists beneath the hole). As the glacier melts, the sediment that had filled the hole slumps down, on top of the ice beneath it (which had not melted, because it is insulated by the material on top). Eventually when the remaining ice finally melts, what was an ice-cored mound of sediment now has a depression in the center, where the ice had been. 1-20-2015

As the stagnant ice on the uplands slowly melted, the glacier surface became more and more irregular. The soupy debris on top of the ice continually slumped and slid, flowing into lower areas, eventually shaping the hummocky, collapsed glacial topography – dead-ice moraine – found today over the uplands. As the stagnant glacial ice melted, and debris slid from higher to lower places, a variety of unusual features resulted. Long ridges formed when sediment slid into cracks in the ice. Such ridges may be straight or irregular, depending on the shape of the cracks. Often, cracks that formed in a rectilinear pattern when the glacial ice was disintegrating, became partly filled with debris that slid into them. Today, we see nearly straight, intersecting ridges, where the ice cracks had been. These ridges are called “disintegration ridges.” Mounds of material collected in holes and depressions in the ice.  If the mounds were cored by ice, when the ice cores melted, the centers of the mounds collapsed, forming circular-shaped ridges – “doughnuts.” Some of the doughnuts are breached on two sides because the debris cover on a mound of ice slid off two sides of the mound. Some geologists have referred to such features as “puckered lips.” Wherever part of the covering of debris slid off an area of ice to a lower place, the newly exposed ice then melted more quickly transforming what had been a hill into a hole or depression. Such reversals of topography continued until all the ice had eventually melted.

Dead-ice moraine, Stutsman Co., North Dakota, geology

Fig. 12-G. Air view of dead-ice moraine, near Woodworth, Stutsman County. This photo was taken in early spring when the snow was mainly melted, but ice still covered most of the pot-hole lakes. Photo scan of University of North Dakota air photo. 1962.

The insulating blanket of debris on top of a stagnant glacier was so thick in places that the cold temperatures of the ice had little or no effect on the surface of the ground. Trees, grasses, and animals lived on the land surface overlying the stagnant glacial ice. As conditions gradually stabilized, water collected in lakes in depressions on the debris-covered glacial ice. Most of the water in the lakes was probably the result of local precipitation rather than from melting ice. Precipitation at the time was greater than it is today, probably 50 or 75 or more inches of rainfall a year. The mean annual temperature was only a few degrees cooler than it is today.

Surrounding the ponds and lakes, the debris on top of a stagnant glacier was forested by spruce, tamarack, birch, and poplar, as well as aquatic mosses and other vegetation, much like parts of northern Minnesota today. This stagnant-ice environment in North Dakota, 10,000 years ago, was in many ways similar to stagnant, sediment-covered glaciers in parts of Alaska today. Fish, clams, and other animals and plants thrived in the numerous lakes. Wooly mammoths, bear, caribou, wapiti, and other large game roamed the broad areas of forested, debris-covered ice.

Dead-ice topography; North Dakota, geology

Fig. 12-I. The two circular ridges shown on this air photo are known as “doughnuts,” landforms characteristic of dead-ice moraine. The three-step diagram (Figure 12-H) shows how doughnuts form.

During the years I was mapping North Dakota geology, I occasionally came across Ice Age fossils in North Dakota’s dead-ice moraine: caribou bones, mammoth teeth, fossil fish (mainly perch), and various kinds of snails, but paleontologists studying the Ice Age fauna and flora in detail have found many more kinds of Ice Age fossils than I noticed.

Modern dead ice; geology, North Dakota

Fig. 12-J. This is a pile of melting snow on the State Capitol grounds, spring of 2013. The discontinuous covering of grass and dirt on top of the snow tends to retard the rate at which it melts. Notice how sediment forms covers on pedestals of melting snow. This behavior is analogous to melting glacial ice, which had a covering of sediment (much thicker than the small amount of covering shown here – the insulating cover on melting stagnant ice may have been hundreds of feet thick, and retarded melting by thousands of years. Photo: 4-27-2013.

 

 

 

 

 

 

Prehistoric people probably lived on the insulated glaciers in North Dakota 10,000 years ago without realizing the ice lay only a few feet below. Or, if they did realize it, they likely accepted it as a normal situation (and I suppose it was normal for that time). Eventually, all the buried ice melted, and all the materials on top of the glacier were lowered to their present position, resulting in the hilly areas of dead-ice moraine we see today.

 

 

 

North Dakota geology, stagnant ice and soil, Alaska glacial debris

Fig. 12-K. This is a glacier in Alaska, covered with debris. In the distance, a forest is growing on the debris, which provides insulation from the ice, which is melting, very slowly. This scene might approximate the stagnant glacial ice on Turtle Mountain, as it was melting, about 12,000 years ago. Photoscan UND Geology Dept. 1962

1-INTRODUCTION TO NORTH DAKOTA GEOLOGY – PART ONE

During my 42 years with the Geological Survey (1962 – 2004), I worked on nearly every facet of North Dakota geology: the rocks that produce oil, gas, coal, gravel, ground water and our other mineral resources. My studies of the glacial sediments near Devils Lake helped me to gain detailed insights into North Dakota’s past climate changes. However, I was always most interested in the origin of the hills and valleys I saw every day as I traveled around the state. I’ve spent a lifetime trying to understand how the land that is North Dakota came to be the way it is. My wife, Mary, and our three children as they came along, lived with me in about 25 North Dakota towns over the years. Our oldest son, Bill, was born in Park River while I was mapping Walsh County, and our daughter, Irene, arrived in Lisbon while I was mapping Ransom County. Paul, the youngest, was born in Grand Forks on the first day of January, when it was too cold to map anywhere. Over the years, we lived, up to six months each, in places like Carrington, Cooperstown, Harvey, Hazen, Mayville, McClusky, Washburn, White Shield, Fort Totten, Fort Yates, Rock Lake, and Turtle Lake. Our summer homes were in towns in about 30 counties, and on four Indian Reservations. We enjoyed every one of them.

Fig. 1-A. Mose is one town we never stayed in. On July 12, 1943, a tornado moved west from the town of McHenry toward Mose, twisting trees out of the ground as it went. As it came, it developed into one of the biggest storms in North Dakota’s history. Twenty-one-year-old Helen Johnson stood in the north window of her home and watched the driveway go, along with a bridge over the ditch at the front of her house. Mose actually survived for another 12 years before the post office finally closed. Mose was located about six miles west of Banford in Griggs County. Photo: 9-10-2009.

Each place was special in some way. North Dakota people are open and friendly, and often interested in geology. When we arrived at a new place, we asked locally if anyone had an apartment for rent and, usually, someone did. In Harvey we rented from the owner of the town bakery—a great choice! In Enderlin, our landlady’s son, a hunter, kept us supplied with pheasants and geese that autumn. In another town, our landlady’s son provided us with wild turkeys (some of them may have been poached—we didn’t ask). In another place, we shared a rental house with some bats. In Fort Yates, the brand-new nursing home was not yet filled and still had room, so that became our home. Our little kids were a hit with the elderly residents. I worked in every part of the state. A “field season” for me usually lasted from sometime in May, beginning when it was dry enough to get around, and ending in November, when the ground was frozen too hard to auger a hole. Just before Thanksgiving, we would move back to our own home in Grand Forks. The day after we got home one year, I raked the yard and put up the storm windows. The next day a blizzard blew, and the snow stayed until spring. Our neighbor, an elderly Norwegian man, commented, in his wonderful accent, “that Bluemle, he always times things right.” Well, I don’t “always time things right,” but I was glad I had that year. For the nearly 25 years that we spent our summers “in the field,” throughout North Dakota, we tended to visualize Grand Forks as a white and snowy “winter wonderland” because we weren’t around much to enjoy it in the summer time. Mary and I claim some important knowledge and understanding of North Dakota, apart from the geology. While mapping, I noted stands of chokecherries, wild plums, buffalo berries and juneberries. That valuable information went on my field maps, right along with the geology, as did the locations of the best places to buy sausage and kuchen.

This witch hit the road sign at the end of the driveway into the Davis Ranch in Slope County, October 23, 2009. She represents my own pondering as I tried to decide “which way to turn” as I constructed this website.

Fig. 1-B. This witch hit the road sign at the end of the driveway into the Davis Ranch in Slope County, October 23, 2009. She represents my own pondering as I tried to decide “which way to turn” as I constructed this website. Photo: 9-10-2009.

Most of the photos I will post on this website will illustrate landforms. I hope they will help readers appreciate and understand the geologic processes that shaped our modern landscape. I took most of them during the summers of 2009, 2010, and 2011 while we traveled throughout the state. The notion to travel around the state in the summer as kind of a “post-retirement” project turned out to be a great decision. To provide purpose, I took photos of geologic features. During some of our trips around the state we got a little more “off the beaten path” than I intended. One day, I drove along a road on the Missouri Coteau that became a trail, and eventually a narrow, mostly washed-out path with no place to turn around easily, so I kept going. Finally, we came to a barricade, so I stopped and walked around it to read the hand-printed sign: “Do Not Enter: Road Impassible.” The seven miles I had just driven were Longhorn cattle.IMG_1789_webimpassible! I dug out a couple of the steel fence posts, drove to the “good” side of the barricade, and replaced the posts and sign. Another day, I walked over to a fence line, took a picture, and stepped in a badger hole and broke my foot. Still another time, we stopped to admire a herd of longhorn cattle, standing on the road, surrounding us. I thought one was particularly handsome so I took his picture through the open window on the passenger side of our van. I felt something cold, turned around, and found myself nose to nose with a cow that had gotten her head in through the open window as far as her horns allowed. I presumed she probably wanted her picture taken too, so I snapped her as well.

Top photo shows the "handsome" Longhorn. Lower photo shows the cow that got her head inside our van. Notice that the bark has been scraped off some trees. Billings County, September 10, 2009

Figs. 1-C & 1-D. Top photo shows the “handsome” Longhorn. Lower photo shows the cow that got her head inside our van. Notice that the bark has been scraped off some trees. Billings County, 9-10-2009.

Many geologists move from country to country around the world; we moved from county to county around the state of North Dakota. Unspoiled prairies and buttes, rivers and lakes, wildflowers and wild fruit are everywhere. Wildlife abounds. Gravel trails lead to broad horizons. Late afternoon summer

This "gravel road leading to broad horizons" shows an area of dead-ice moraine topography with a crop-dusting airplane spraying a weed-infested slough area. About six miles south of Hurdsfield, Wells County, August 8, 2009.

Fig. 1-E. This “gravel road leading to broad horizons” shows an area of dead-ice moraine topography with a crop-dusting airplane spraying a weed-infested slough area. About six miles south of Hurdsfield, Wells County. Photo: 8-8-2010.

showers are followed by spectacular sunsets. The prairie landscapes are multi-dimensional. Their breadths, elevations and depths reflect geologic events and processes I’ll explore on this website. And the geology is always there. Geology opens the door to another world just beneath the familiar scenes of our everyday lives. It takes us outdoors as we explore the intricacies of our Earth’s history. Mary and I have traveled beyond North Dakota–to most of the states and Canadian provinces and about 20 other countries. Much of our travel has been to enjoy geology. We’ve seen a lot of spectacular geology in places like Montana, Alberta, and Sweden. Scotland is my favorite destination for geology and for the history of the science of geology. Our geology, here in North Dakota, may be more subtle than the places I just mentioned, but it is just as interesting. My career has been satisfying, my work interesting and rewarding. Every day on the job was different for me. Whether it was the glorious summer days in the field, mapping geology, or wintry days I spent in my office, piecing together and trying to understand what I had mapped the previous summer, it was always fascinating.

Fig. 1-F. “A Tree Grows in Hatton.” This tree in the park has its roots in the air. I don’t think it represents one of the intricacies of our earth’s history, just someone with a backhoe, a sense of humor, and some extra time. This part of Traill County, which includes the Hatton area, is part of the Elk Valley Delta in which sandy silt was deposited by streams flowing into Glacial Lake Agassiz. I took this photo on May 31, 2010.

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