A geomorphic history based on topographic map evidence

This overview essay  provides highlights from more detailed essays, which interpret topographic map evidence to determine North Dakota Missouri River drainage basin landform origins. The detailed essays can be found under ND Missouri River on this website’s sidebar category list. The Missouri River enters North Dakota west of Williston and flows in an east, southeast, east, and south-southeast direction and leaves the state south of Fort Yates. Major North Dakota Missouri River tributaries are from the southwest and west and are the Little Missouri, Knife, Heart, and Cannonball Rivers. There are no major North Dakota tributaries from the north and east, although the south-oriented James River, which originates in North Dakota, does join the Missouri River in southern South Dakota. North and east of the North Dakota Missouri River is the Missouri Coteau, which is an area of poorly drained glacial moraines. Northeast and east of the Missouri Coteau is the northeast and east-facing Missouri Escarpment, the base of which is significantly lower in elevation than the topographic surface into which the Missouri River valley has been eroded. The Missouri Coteau in northwest and north central North Dakota forms the north-south continental divide while in south central North Dakota the Missouri Coteau forms the Missouri River-James River drainage divide. North Dakota Missouri River drainage basin evolution is closely related to rapid melting of a thick North American ice sheet, which had been located in a large and deep “hole”. Late during the ice sheet’s rapid melt down, a large southeast and south-oriented supra-glacial river carved a giant southeast and south-oriented ice-walled and bedrock-floored canyon into the ice sheet’s surface and the northeast and east-facing Missouri Escarpment represents what is left of that canyon’s southwest and west wall. Immense southeast-oriented ice-marginal floods then breached the decaying and detached ice sheet southwest margin, which had been forming an ice barrier, and the ice-marginal floods then flowed onto the deep canyon floor. A climate change triggered by reversals of south-oriented melt water floods caused by the opening up of more northern melt water flood flow routes then ended the rapid ice sheet melting and resulted in a new thin ice sheet, which blocked the ice sheet margin breaches, and which forced the newly eroded northeast and east-oriented drainage system to erode the present day south-oriented North Dakota Missouri River valley.

Figure 1: Regional map showing the North Dakota Missouri River drainage basin location in western and central North Dakota (select and click on maps to enlarge). National Geographic Society map digitally presented using National Geographic Society TOPO software.

North Dakota Missouri River drainage basin drainage history

This North Dakota Missouri River drainage basin landform origins overview essay provides highlights from more detailed essays, which use topographic map evidence to interpret Missouri River drainage basin landform origins within the state of North Dakota. The detailed essays are found under ND Missouri River on this website’s sidebar category list. The Missouri River originates at the confluence of major tributaries at Three Forks, Montana and flows in a north and east direction to enter North Dakota west of Williston. Essays describing Missouri River drainage basin landform origins in Montana are found under MT Missouri River on this website’s sidebar category list (and also under names of major Missouri River tributaries in Montana). Once in North Dakota the Missouri River flows in a northeast, east, southeast, east, and south-southeast direction and enters South Dakota a short distance south of Fort Yates, North Dakota. Essays describing Missouri River drainage basin landform origins in South Dakota are found under SD Missouri River on the sidebar category list. Today the Missouri River valley upstream from Garrison Dam in central North Dakota is flooded by Lake Sakakawea, which extends upstream almost to Williston, North Dakota. South of Bismarck, North Dakota the Missouri River valley is flooded by Lake Oahe, which is a large reservoir formed by Oahe Dam, which is located near Pierre, South Dakota. Major Missouri River tributaries in North Dakota include the southeast and northeast-oriented Cannonball, Heart, and Knife Rivers and the north and east-oriented Little Missouri River. Cannonball, Heart, and Knife River drainage basin and Little Missouri River drainage basin essays are found under North Dakota Missouri Slope and Little Missouri River on the sidebar category list. The Missouri River in North Dakota has no major tributaries from the north or east, although the south-oriented James River, which originates in central North Dakota east of the Missouri River, joins the Missouri River in southern South Dakota. James River drainage basin essays are found under James River on the sidebar category list.

Figure 2: Region north and east of flooded Missouri River valley in Garrison Dam area of central North Dakota. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

North and east of the North Dakota Missouri River valley is the Missouri Coteau, which on topographic maps appears to be a poorly drained region, about 20-40 kilometers wide, and which is covered by what appears to be glacial moraine material and which in North Dakota extends parallel to the Missouri River from northwest North Dakota to the South Dakota border (and south into South Dakota). Figure 2 uses reduced size topographic maps to illustrate the flooded Missouri River valley immediately upstream from Garrison Dam, which is located in the figure 2 southwest corner area. The Missouri River flows in an east and then south direction in the figure 2 southwest corner area to reach Garrison Dam. Note how north and east of the flooded Missouri River valley the landscape is poorly drained and hummocky and has many small lakes, all typical of glacial moraine areas, and also typical of Missouri Coteau southwest margin areas. Note also the flooded southwest-oriented Missouri River tributary valley (the Snake Creek valley) and the flooded northwest-oriented valley (the Lake Audubon valley), which will be discussed later in this essay. North and east of the figure 2 map area the Missouri Coteau glacial moraine characteristics become even more pronounced, right up to the Missouri Escarpment crest, which in North Dakota is located along the Missouri Coteau northeast and east margin. The Missouri Escarpment is a northeast and east-facing escarpment, which also in North Dakota roughly parallels the route of the Missouri River and is illustrated in figure 3 below, which shows a region north of figure 2 (the major north-oriented highway continues in a north direction to Minot, North Dakota, which is the city located in figure 3). The poorly defined north-south continental divide is today located in the Missouri Coteau region between the Missouri River valley located in figure 2 and the Missouri Escarpment crest located in figure 3. The southeast-oriented river located in figure 3 is the Souris River, which south and east of the figure 3 map area makes a U-turn to flow in a northwest and north direction and which is located in the Hudson Bay drainage basin. Figure 4 illustrates the Turtle Mountain Escarpment located north and east of the figure 3 map and which is located on the northeast side of the lowland containing Souris River loop.

Figure 3: Northeast-facing Missouri Escarpment located south and west of Minot, North Dakota. The Missouri Coteau is the region of hummocky topography located south and west of the Missouri Escarpment crest. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

The Missouri Escarpment shown in figure 3 averages about 100 meters in height and elevations at the escarpment base are significantly lower than elevations of the surface into which the Missouri River valley has been eroded. In north central North Dakota the lowland at the Missouri Escarpment base is drained by the southeast, northeast, northwest, and north-oriented Souris River, which is flowing at a significantly lower elevation than the figure 2 landscape into which the Missouri River valley has been  eroded. The Souris River valley in the Minot area has an elevation of between 470-480 meters and the Lake Sakakawea average pool level is 560 meters, with the regional surface into which the Missouri River valley has been eroded averaging 600 meters or more in elevation. Note how the Missouri Coteau region in the figure 3 southwest third appears to be covered with much “fresher” looking glacial moraines than the Missouri Coteau region located in the figure 2 regions north and east of the Missouri River valley. The distance between the figure 2 and figure 3 map areas is approximately 30 kilometers. Between the figure 2 and figure 3 map areas there are no streams of any consequence, although there are numerous small lakes as seen in figure 3 and also in figure 2. The Missouri Coteau appears to be a region where an ice sheet loaded with debris slowly melted and deposited the debris where the ice melted. The Missouri Coteau southwest margin probably was eroded more than areas near the Missouri Escarpment crest, which accounts for at least some of the difference in surface appearance.

Figure 4: Southwest-facing Turtle Mountains escarpment and north-northwest oriented Souris River. Bottineau is the town located at the Turtle Mountain escarpment base near the figure 4 east edge. There is a gap of approximately 30 kilometers between the figure 3 and figure 4 map areas (see figure 1). United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figures 3 and 4 illustrate a very different topography in the lowland located north and east of the Missouri Escarpment base. First, the Missouri Coteau type hummocky topography is almost completely absent on the lowland floor. Second, the lowland floor, while not everywhere well-drained, is drained by the southeast, northeast, northwest, and north-oriented Souris River and its tributary streams. Third, the lowland floor is approximately 100-200 meters lower than the Missouri Coteau regions to the south and west. Figure 4 illustrates what is located on the northeast side of the North Dakota Souris River loop lowland. The Turtle Mountains located in the figure 4 northeast corner are today an isolated upland region surrounded by Missouri Escarpment type escarpments, especially on the southwest margin. The upland region has many of the same glacial moraine type characteristics found on Missouri Coteau, is poorly drained, and has an elevation similar to the Missouri Coteau elevations. To understand the North Dakota Missouri River drainage basin drainage history it is necessary to understand the Missouri Escarpment, Missouri Coteau, Souris River, and Turtle Mountain history as well. These major landforms have never been well explained in the geology or geomorphology literature and are being explained for the first time in this Missouri River drainage basin landform origins research project essay series.

• The North Dakota Missouri River drainage basin began with the development of a North American ice sheet comparable in size to the present day Antarctic Ice Sheet, if not larger. The ice sheet was thick, probably several kilometers thick, and was located in a deep “hole”, which the ice sheet had formed by a combination of deep glacial erosion and crustal warping caused by the ice sheet weight. When it at its maximum size the ice sheet stood high above the pre-glacial surface, but also had roots that extended well below the pre-glacial surface, which no longer exists. The pre-glacial surface under the ice sheet had been completely destroyed by deep glacial erosion and the pre-glacial surface adjacent to the ice sheet and elsewhere on the North American continent was being deeply eroded by deep melt water flood erosion and was also probably being significantly altered by crustal warping caused by the thick North American ice sheet presence.

• Events important to the North Dakota Missouri River drainage basin drainage history began as the ice sheet was rapidly melting and had melted to the point it no longer stood high above the surrounding non-glaciated surface, which had probably already been significantly lowered by deep melt water erosion. At that time immense melt water rivers were flowing in a southeast direction along the ice sheet’s southwest margin and were deeply eroding the region between the present day Pine Ridge Escarpment in South Dakota and the ice sheet margin. Also at that time immense southeast and south-oriented supra-glacial melt water rivers were flowing across the ice sheet surface to the ice sheet’s southern margin and carving giant ice-walled and bedrock-floored canyons. A huge southeast and south-oriented ice-walled and bedrock-floored canyon was carved east of the present day Missouri River valley in North and South Dakota and the Missouri Escarpment is what remains of that giant canyon’s west and southwest wall. The floor of that huge ice-walled and bedrock-floored canyon was significantly lower in elevation than the bedrock surface south and west of the decaying ice sheet and separating the immense southeast-oriented ice marginal floods from the much deeper ice-walled and bedrock floored canyon floor was the decaying and detached ice sheet southwest margin or ice barrier.

Figure 5: Sheyenne River headwaters and Missouri Escarpment base in west of Harvey in central North Dakota. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

As the ice sheet’s southwest margin continued to decay the southeast-oriented ice marginal floods, which were flowing at a higher elevation than deep ice-walled and bedrock-floored canyon floor to the northeast and east began to breach the ice barrier and to flow into the giant ice-walled and bedrock-floored canyon. Evidence for those breaches is today located along the Missouri Escarpment where deep valleys have been eroded into the Missouri Escarpment slope. Figure 5 illustrates one such deep valley located west of Harvey, North Dakota. The northwest-southeast oriented Missouri Escarpment extends from the figure 5 northwest corner area to the figure 5 east edge (south half). Today these deep valleys are partially filled with what on topographic maps appear to be glacial deposits, and it is possible to trace at least some of these valleys from the present day Missouri River valley to the Missouri Escarpment and sometimes even further. The northwest-oriented flooded valley in figure 2 east of Garrison Dam was eroded by flood waters moving east through ice sheet margin breaches and can be linked to this figure 5 abandoned valley. The lowland at the Missouri Escarpment base in figure 5 is located south and east of the Souris River loop and the stream flowing to the figure 5 east center edge is the Sheyenne River, which originates on the Missouri Escarpment slope just north of the abandoned valley in the figure 5 west center area. Figure 2 shows the Sheyenne River course as it flows in a northeast, east-northeast, southeast, and south direction to Lisbon, North Dakota, where like the Souris River, the Sheyenne River makes a U-turn and turns to flow in a northeast direction to join the north-oriented Red River (located east of the figure 2 map area), which eventually drains to Hudson Bay.

Figure 6: Missouri River valley from Yellowstone River confluence area to mouth of south-oriented Little Muddy River near Williston, North Dakota. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Why does the southeast-oriented Souris River, which flows along the Missouri Escarpment base, make an abrupt U-turn and flow north and why does the Sheyenne River, which for a short distance south and east of the Souris River loop flow along the Missouri Escarpment base before flowing across the lowland surface and then turning to flow in a south direction also make an abrupt U-turn so as to flow north? When breaches were opening up in the ice sheet’s southwest margin, which permitted the immense southeast-oriented ice-marginal melt water floods to flow into the deep ice-walled and bedrock-floored canyon located to the east and northeast of the ice sheet southwest margin, what had been large south-oriented melt water rivers in those deep ice-walled canyons had been captured and diverted north and east as new and lower outlets to the present day Saint Lawrence River drainage basin and later to what is now Hudson Bay had opened up. The breaches in the decaying ice sheet southwest margin ice barrier triggered the headward erosion of deep northeast and north oriented valleys which began to capture the southeast-oriented ice-marginal floods as the deep north and northeast-oriented valleys eroded headward across the region south and west of the ice sheet margin.

• The opening up of the ice margin breaches began in the south and progressed northward, which meant deep northeast-oriented valleys eroded headward in sequence. Figure 2 illustrates how the Cannonball, Heart, and Knife Rivers all flow in northeast directions to reach the south-oriented Missouri River as barbed tributaries. Figure 2 also illustrates how the Little Missouri River flows in a north and east direction to join an east oriented Missouri River segment. That east oriented Missouri River valley segment was initiated as a deep ice-marginal east and southeast-oriented valley eroded headward from an ice-margin breach located east of Garrison Dam. The north-oriented Little Missouri River valley eroded south from that east and southeast-oriented valley to capture all southeast-oriented melt water moving between the ice sheet margin and the Black Hills. West of the north-oriented Little Missouri River in figure 2 is the northeast-oriented Yellowstone River. Figure 6 illustrates the Yellowstone River confluence with the Missouri River. Note how a southeast-oriented Missouri River turns at its junction with the Yellowstone River to flow in a northeast direction to the mouth of the south-oriented Little Muddy River near Williston. The south-oriented Little Muddy River is located in a large north-northeast oriented valley, which was the location of a major ice margin breach.

Figure 7: Abandoned north-northeast oriented valley eroded into Missouri Escarpment slope north of south-oriented Little Muddy River valley seen in figure 6. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 7 illustrates the north end of the deep north-oriented “Yellowstone River” valley seen in figure 6, which had eroded headward from the ice-walled canyon’s southwest wall across what was then the decaying and detached ice sheet southwest margin and then eroded headward across eastern Montana to capture the same southeast-oriented flood waters Little Missouri River valley headward erosion had previously captured. Today between the large south-oriented Little Muddy River valley seen in figure 6 and the northeast oriented abandoned valley seen in figure 7 there is a stretch of almost 30 kilometers where the north-northeast oriented valleys is filled with glacial deposits. Why are the deep northeast and east-oriented valleys, which were eroded at the ice sheet margin breach locations, now filled with glacial deposits? To answer that question think about what the immense south-oriented melt water floods were doing when they were captured and diverted north. Those massive south-oriented melt water floods had been flowing to the Gulf of Mexico and forcing warm Gulf of Mexico waters into the Atlantic Ocean, where the warm waters then moved north to warm Northern Hemisphere climates. When those immense south-oriented floods were captured so as to flow across what had been the ice sheet’s floor in northward directions the flood waters then began to displace what were cold waters, which then moved south into the Atlantic Ocean to cool the North Hemisphere climate.

• The resulting climatic change halted the ice sheet’s rapid melting and north-oriented flood waters located on the ice sheet floor began to freeze, with what for all practical purposes was a thin ice sheet beginning to form. Incorporated into that new thin ice sheet were the isolated and rejuvenated thick ice sheet remnants, including remnants of what had been the decaying ice sheet’s southwest margin ice barrier. The resulting thin ice sheet blocked the breaches through the ice sheet’s southwest margin, which had the effect of damming the newly eroded and deep northeast oriented valleys at the ice sheet’s southwest margin. Water spilled from one valley segment to another along the ice sheet margin, which resulted in headward erosion of the present day North Dakota Missouri River valley. Unlike the previous thick ice sheet, the new thin ice sheet did not deeply erode the underlying landscape, although it did alter some surface features. Because the new thin ice sheet ice between former thick ice sheet remnants was formed by the freezing of north-oriented flood water, the frozen flood water areas tended to be wet based, which meant large slabs of ice could easily move and sometimes carry underlying slabs of frozen bedrock with them. Such movements of wet based frozen flood water, which also included frozen slabs of the underlying bedrock, combined with expansion of the rejuvenated thick ice sheet remnants along the ice sheet’s southwest margin, partially filled the northeast and east-oriented valleys, which had previously been eroded across the ice sheet’s southwest margin. The thin ice sheet did melt, with areas between the rejuvenated thick remnants melting first. The thick ice sheet remnants melted much more slowly and today in North Dakota include the Missouri Coteau and Turtle Mountain upland area.

Introduction to Missouri River drainage basin research project essay series

• This North Dakota Missouri River drainage basin landform origins overview essay and its related detailed essays is one of a series of overview essays and related detailed essays in the Missouri River drainage basin landform origins research project. The research project goal is to use topographic map evidence to describe the evolution of drainage divides separating each significant present day Missouri River tributary valley and also to describe the evolution of drainage divides separating the present day Missouri River drainage basin from adjacent drainage basins. Each overview essay and its related detailed essays pertains to a specific Missouri River tributary, tributary to a present day Missouri River tributary, or a present day Missouri River valley segment. Each detailed essay illustrates and discusses detailed topographic map evidence describing the evolution of a secondary drainage divide separating specified Missouri River tributary valleys.

• The Missouri River drainage basin research project introduces a new regional geomorphology paradigm. An essay titled “About the ‘thick ice sheet that melted fast’ geomorphology paradigm” provides a brief introduction to the new paradigm and how the new paradigm emerged. Detailed evidence illustrated and discussed in the Missouri River drainage basin research project builds a strong case for (1) deep glacial erosion of the North American continent by a thick North American ice sheet that created and occupied a deep “hole”, (2) rapid melting of that thick North American ice sheet, (3) immense floods of south-oriented melt water, (4) headward erosion of deep east, northeast and north-oriented valley systems to capture the south-oriented melt water floods and to divert the melt water further and further northeast into space the ice sheet had once occupied, (5) deep flood water erosion of the North American continent surface, and (6) crustal warping that resulted in uplift of mountain ranges as flood waters were deeply eroding what are now high mountain regions. This interpretation is fundamentally different from most previous interpretations. The North Dakota Missouri River drainage basin landform origins evidence in this overview essay and its related detailed essays is presented for review and discussion by qualified research geomorphologists and geologists.

Additional information and sources of maps studied

This essay has provided only a sample of the detailed topographic map evidence supporting the flood erosion interpretation. Many additional illustrations could be provided. Readers are encouraged to look at mosaics of detailed topographic maps to see the abundance of available data. Maps used in this study were created and published by the United States Geologic Survey and can be obtained directly from the United States Geological Survey and/or from dealers offering United States Geological Survey maps. Hard copy maps can also be observed at United States Geological Survey map depositories which are located throughout the United States and elsewhere. Illustrations used here were created using National Geographic Society TOPO software and digital map data. TOPO software and map data can be obtained from the National Geographic Society and/or dealers offering National Geographic Society digital map data.