A geomorphic history based on topographic map evidence

The Pipestem Creek-James River drainage divide area discussed here is located in Wells, Foster, and Stutsman Counties, North Dakota, USA. Major nearby landforms present include the Missouri Escarpment and the Missouri Coteau. Pipestem Creek is a major James River tributary, which flows along the Missouri Escarpment base. The James River and Pipestem Creek originate near a major indentation in the Missouri Escarpment. Landforms in the drainage divide area formed during a thick North American ice sheet’s rapid melt down. Thick ice sheet rapid melting produced immense floods, which late during the ice sheet melt down history flowed southeast and south in the Pipestem Creek and James River drainage basins. A minor glacial event may have followed the immense southeast and south-oriented flood flow.

• The purpose of this essay is to use topographic map interpretation methods to explore Pipestem Creek-James River drainage divide area landform origins in Wells, Foster, and Stutsman Counties North Dakota, USA. Map interpretation methods can be used to unravel many geomorphic events leading up to formation of present-day drainage routes and development of other landform features. While each detailed topographic map feature provides detailed evidence to be explained, the solution must be consistent with explanations for adjacent area map evidence as well as solutions to big picture map evidence puzzles. I invite readers to improve upon my solutions and/or to propose alternate solutions that better explain evidence and are also consistent with adjacent map area and big picture evidence. Readers may do so either by making comments here or by writing and publishing their own essays and then by leaving a link to those essays in a comment here.

• This essay is also exploring a new geomorphology paradigm in which erosional landforms are interpreted as evidence left by immense glacial melt water floods. Implied in that interpretation is the immense floods were derived from a thick North American ice sheet that created a deep “hole” in the North American continent and also melted fast. The previously unexplored paradigm being tested in this and other Missouri River drainage basin landform origins research project essays is a thick North American ice sheet, comparable in thickness to the Antarctic ice sheet, occupied the North American region usually recognized to have been glaciated, and through its weight and erosive actions created a deep North American “hole”. The southwestern rim of that deep “hole” is today preserved in the high Rocky Mountains. The ice sheet through its weight and deep erosion (and perhaps deposition along major south-oriented melt water flow routes) caused significant crustal warping and tectonic change, through its action of melting fast produced immense floods that flowed across the continent, and through its action of melting fast systematically opened up space in the ice sheet created “hole” so headward erosion of newly developed north-oriented drainage systems captured immense south-oriented melt water floods and diverted immense melt water floods north into space the ice sheet had once occupied.

• If this previously unexplored paradigm is correct the geographic region explored by this essay should contain evidence of immense floods that were captured by headward erosion of new valley systems so as to cause the floods to flow in a different direction. Ability of this previously unexplored paradigm to explain Pipestem Creek-James River drainage divide area landform evidence in Wells, Foster, and Stutsman Counties, North Dakota will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm. This essay is included in the Missouri River drainage basin landform origins research project essay collection.

Pipestem Creek-James River drainage divide area location map

Figure 1: Pipestem Creek-James River drainage divide area location map (select and click on maps to enlarge). National Geographic Society map digitally presented using National Geographic Society TOPO software.

Figure 1 provides a Pipestem Creek-James River drainage divide location map and also illustrates a large area in central and eastern North Dakota. Pipestem Creek joins the James River near Jamestown, North Dakota, which is located near the northwest corner of the figure 1 southeast quadrant. Pipestem Creek originates northwest of Jamestown near the town of Bowdon and flows generally east to Sykeston. East of Sykeston Pipestem Creek turns to flow southeast and joins the south-oriented James River at Jamestown. The James River originates northwest of Bowdon and flows north to Manfred where it turns southeast and east to flow to Bremen, New Rockford, and Grace City. Near Grace City the James River turns to flow south to Jamestown. South of Jamestown the James River flows southeast to the figure 1 south edge and eventually joins the southeast-oriented Missouri River in southern South Dakota. The Missouri River is located in the figure 1 southwest quadrant and flows from Garrison Dam (located near the figure 1 west center edge) in a south-southeast direction to Bismarck and then to the figure 1 south edge. Another river important to this essay is the Sheyenne River, which originates west of Harvey (northwest of Bowdon) and then flows northeast through Harvey before turning to flow generally east to near Kloten. Near Kloten the Sheyenne River turns south to flow to Valley City and Fort Ransom. At Fort Ransom the Sheyenne River begins to turn, first southeast and then northeast and joins the north-oriented Red River near Fargo. The Red River is in the Hudson Bay drainage basin while the Missouri River is in the Gulf of Mexico drainage basin. The north-south continental divide is located between the James River and Sheyenne River, with James River water flowing south to the Gulf of Mexico and Sheyenne River water flowing north to Hudson Bay. The Sheyenne River elbow of capture in the Fort Ransom area provides evidence the Sheyenne River drainage basin upstream from the Fort Ransom area once drained south to the Gulf of Mexico and was subsequently captured so as to flow north to Hudson Bay. A similar elbow of capture can be seen on the Souris River in the figure 1 northwest quadrant. The Souris River flows southeast through Minot to Velva and then turns northeast to Towner. At Towner the Souris River turns to flow northwest to the figure 1 north edge. North of figure 1 Souris River water eventually reaches the north-oriented Red River, which eventually reaches Hudson Bay. The Souris River elbow of capture provides evidence the Souris River drainage basin upstream from Velva once drained southeast into central North Dakota and probably south to the Gulf of Mexico, but like the Sheyenne River it was captured and diverted north to flow to Hudson Bay. Between the Missouri River and the Souris River and also between the Missouri River and Pipestem Creek there is a broad area, which on figure 1 lacks an integrated drainage pattern. That region is known as the Missouri Coteau. The northeast and east edge of the Missouri Coteau is a northeast and east-facing escarpment known as the Missouri Escarpment. The Souris River flows in a northwest-southeast oriented lowland at the Missouri Escarpment base. Pipestem Creek and the James River (except for their headwaters areas) also flow in that same northwest-southeast oriented lowland.

Pipestem Creek-James River drainage divide area detailed location map

Figure 2 provides a somewhat more detailed map of the Pipestem Creek-James River drainage divide area. Eddy, Wells, Foster, Griggs, Kidder, Stutsman, and Barnes are names of North Dakota counties. The red shaded area in Eddy County is Fort Totten Indian Reservation (since renamed Spirit Lake Reservation) land. The Sheyenne River flows northeast through Harvey in the figure 2 northwest corner and in the figure 2 northeast quadrant is the Fort Totten Indian Reservation southern boundary before turning southeast and south to flow to Valley City located in the figure 2 southeast corner. The James River begins in Wells County (south of Harvey) and flows north and southeast to Manfred. The James River then flows northeast and southeast to New Rockford in Eddy County and to Grace City in Foster County, before turning south to flow through the Arrowhead National Wildlife Refuge and to flow to Jamestown near the figure 2 south edge. Pipestem Creek originates near Bowdon in southeast Wells County and meanders east to Sykeston and Dover and then turns to flow southeast to join the James River at Jamestown. The area with many small lakes in western Stutsman County, Kidder County, and southwest Wells County is the Missouri Coteau. Between the Missouri Coteau and Pipestem Creek is the east-northeast facing Missouri Escarpment. Several high points along the Escarpment crest are marked including Hawks Nest in southeast Wells County and Mount Moriah, Brush Hills, and Round Top in northern Stutsman County. The Missouri Escarpment also extends in a northwest direction across southwest Wells County, although there are several significant indentations, which make the Escarpment less pronounced than further to the northwest or southeast. Northeast and east of the Missouri Escarpment is a northwest-southeast oriented lowland, which in north central North Dakota is bounded to the northeast and east by the Turtle Mountain upland region and in South Dakota by the Prairie Coteau upland region. In the region shown in figure 2 there is no obvious northeast or eastern boundary. The northwest-southeast oriented lowland is named in this Missouri River drainage basin research project essay series as the Midcontinent Trench. The Midcontinent Trench was eroded as an immense southeast and south-oriented ice-walled and bedrock-floored valley sliced headward into a thick and rapidly melting North American ice sheet. The immense southeast and south-oriented melt water river that flowed on the Midcontinent Trench floor is named in this essay series as the Midcontinent River. The Missouri Escarpment formed as the Midcontinent Trench’s southwest and west wall. The northeast and east valley wall is today discontinuous, having been eroded when the Midcontinent River was systematically captured and diverted to flow north to Hudson Bay. Evidence for two of the captures and diversions of water to the north was illustrated and discussed in figure 1, where the Sheyenne River and the Souris River were shown to make U-turns so as to flow north.

James River-Pipestem Creek drainage divide near Bowdon, North Dakota

Figure 3: James River-Pipestem Creek drainage divide near Bowdon, North Dakota. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 3 illustrates the James River-Pipestem Creek drainage divide area near Bowdon, North Dakota. Pipestem Creek originates south of Bowdon and flows northeast in the figure 3 south center area and then turns southeast and east to flow to the figure 3 southeast corner. Pipestem Creek as seen in figure 10 below eventually joins the south-oriented James River, which flows to the Missouri River. Rock Run also originates south of Bowdon and flows north (just west of Bowdon) and then turns northeast to flow (with a major southeast jog) to the figure 3 northeast corner area. From the figure 3 map area Rocky Run flows roughly in a northeast direction to join the James River. Northwest-oriented streams along the figure 3 west edge are James River headwaters. From figure 3 the James River flows into the figure 4 map area seen below. Note how figure 3 landscape has been shaped in a northwest-southeast direction and how in addition to the northwest-oriented James River headwaters Rocky Run and Pipestem Creek have southeast oriented valley segments. This northwest-southeast orientation of figure 3 landscape features and of present day drainage routes provides evidence of large-scale southeast oriented flooding prior to development of the present day drainage network. Southeast-oriented flood water moving across the figure 3 map area was first captured by headward erosion of the shallow Pipestem Creek valley. Headward erosion of the Rocky Run valley next captured the southeast oriented flood waters, with the north-oriented Rocky Run headwaters valley south of Bowdon probably being eroded by reversed flood flow on a beheaded southeast- and/or south-oriented flood flow route. The northwest-oriented James River headwaters valley (and northwest-oriented James River tributary valley) were eroded by reversed flow on beheaded southeast-oriented flood flow routes when the James River valley eroded headward into the region. Southeast-oriented flood waters were probably flowing in the ice-walled and bedrock-floored Midcontinent Trench and represented the final large-scale southeast oriented flood flow event to reach the figure 3 map area. Headward erosion of the James River and Sheyenne River valleys (see figure 4 below) captured all flood flow from the northwest and probably the north central Midcontinent River capture event recorded by the present day Souris River U-turn (illustrated and discussed in figure 1 above) occurred at about the same time. Subsequent to those captures the figure 3 map area may have been affected by thin ice sheets that did not significantly alter the drainage system.

Sheyenne River-James River drainage divide area near Manfred, North Dakota

Figure 4: Sheyenne River-James River drainage divide area near Manfred, North Dakota. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 4 illustrates the Sheyenne River-James River drainage divide area near Manfred and north and west of the figure 3 map area. The James River flows north in the figure 4 south center area and then northeast to the red highway. At the red highway the James River turns to flow southeast to Manfred and then east to the figure 4 east edge. Note the James River tributary in the figure 4 southwest corner, which flows northwest before turning northeast to flow to the James River. Also, note the James River valley is shallow compared to the Sheyenne River valley in the figure 4 northwest quadrant. The Sheyenne River flows northeast and north in the figure 4 northwest quadrant and north of figure 4 turns northeast, east, and eventually south to flow to Valley City and Fort Ransom as seen in figure 1. As illustrated in figure 1 the James River and the Sheyenne River flow to opposite sides of the North American continent. Water in the Sheyenne River eventually reaches Hudson Bay while water in the James River eventually reaches the Gulf of Mexico. How could a north-south continental divide be located between two rivers separated by relatively flat land? As previously described this figure 4 map area is located on the Midcontinent Trench floor and the Midcontinent Trench was eroded by an immense southeast and south-oriented melt water river (the Midcontinent River) that sliced an ice-walled and bedrock-floored valley headward into a rapidly melting thick ice sheet. Also, as previously mentioned late during the thick ice sheet’s melt down the Midcontinent River was systematically dismembered with flood waters captured and diverted to flow north in the present day Red River valley. The first capture event occurred in southeast North Dakota where the eastern half of the immense Midcontinent River was captured and diverted northeast to what was then newly reversed (from south-oriented to north-oriented) flood flow in the present day Red River valley. The western half of the Midcontinent River was not captured and continued to flow south. The Sheyenne River valley eroded headward along the eastern half of the Midcontinent River that had been captured while the James River valley eroded headward along the western half of the Midcontinent River that had not been captured. Probably headward erosion of both valleys reached the figure 4 map area after the entire Midcontinent River flow had been captured and diverted north further to the northwest in north central North Dakota (see Souris River U-turn in figure 1). Figure 4 does contain evidence for a subsequent glacial event. Some of the linear ridges in figure 4 (e.g. the ridge adjacent to the James River in the figure 4 center south area) appear to be eskers. Also, the hill southeast of Egg Lake in the figure 4 northwest quadrant appears to be an ice lifted bedrock slab removed from the Egg Lake basin area. These features suggest a wet based thin ice sheet probably covered the figure 4 map area, although there is no evidence the thin ice sheet altered the landscape in the same way the previous thick ice sheet had altered the landscape.

Rocky Run-Pipestem Creek drainage divide northwest of Carrington

Figure 5: Rocky Run-Pipestem Creek drainage divide northwest of Carrington. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 5 illustrates the Rocky Run-Pipestem Creek drainage divide area northwest of Carrington and east of the figure 3 map area. Rocky Run flows east and northeast from Cathy (located along the figure 5 west edge) to the figure 5 north edge. North and east of figure 5 Rocky Run joins the southeast and south-oriented James River (see figure 2). South of Rocky Run and located in the figure 5 center area is northeast, southeast, and northeast-oriented Scotts Slough, which east of figure 5 joins southeast-oriented Kelly Creek, which can be seen in the figure 5 northeast corner and which flows to the south-oriented James River. Pipestem Creek flows north-northeast in the figure 5 southwest corner and then turns to flow southeast to the figure 5 south center edge area. Southeast-oriented drainage route segments and northwest-southeast oriented landscape features probably were initiated by southeast-oriented Midcontinent River flood waters that flowed across the figure 5 map area. As previously mentioned the region probably experienced a minor glacial event following capture and diversion of the Midcontinent River flood waters, although unlike figure 4 the figure 5 map area evidence can be explained without such a glacial event. However, because adjacent areas do contain evidence of wet based thin ice sheets the figure 5 map area probably was also covered by wet based thin ice sheets. Why would wet based thin ice sheets be present on the Midcontinent Trench floor, which has been interpreted here to have been the floor of a giant ice-walled and bedrock-floored canyon carved into a decaying thick ice sheet? Previous discussions described how during most of the thick ice sheet rapid melt down melt water floods moved to the Gulf of Mexico. As the thick ice sheet melt down progressed and when the ice sheet elevation fell below the ice sheet rim elevation melt water flood flow routes changed with flood waters being directed into the “hole” the ice sheet had occupied. However, even after flowing northeast into the “hole” the flood waters, until very late during the melt down history, turned to flow south on the former ice sheet floor (in giant ice-walled and bedrock-floored river valleys, such as the Midcontinent Trench). Very late during the thick ice sheet melt down these immense south-oriented melt water flood rivers were captured and diverted north (see evidence in figure 1 above). The sudden change in flood water flow from the Gulf of Mexico to Hudson Bay significantly altered Atlantic Ocean currents. Instead of moving warm tropical water north to warm Northern Hemisphere climates the Atlantic Ocean currents began to move cold Arctic region waters south to cool Northern Hemisphere climates. This sudden Northern Hemisphere cooling stopped the thick ice sheet rapid melt down and also froze melt water floods on the former ice sheet floor. In addition, immense ice marginal floods still south and west of the thick ice sheet southwest margin were headed northeast into the “hole” the thick ice sheet had occupied. As those flood waters entered the “hole” and began to flow north they also froze. The result was rapid formation of a wet based thin ice sheet with reinvigorated remnants of the former thick ice sheet embedded in it. In places water saturated bedrock froze solid with the thin ice sheet above it. Some of these frozen bedrock slabs were lifted and moved when for various reasons the wet based thin ice sheets moved. Otherwise the wet based thin ice sheets did not significantly alter the landscape.

Pipestem Creek-James River drainage divide area southeast of Carrington

Figure 6: Pipestem Creek-James River drainage divide area southeast of Carrington. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 6 illustrates the Pipestem Creek-James River drainage divide area southeast of Carrington, North Dakota. Carrington is located in the figure 6 northwest corner. Pipestem Creek can just barely be seen where it flows southeast across the figure 6 southwest corner. The James River flows south along the figure 6 east edge area. Southeast-oriented Kelly Creek is located in the figure 6 northeast quadrant and joins the south-oriented James River. One of the more obvious figure 6 landscape features are the anastomosing channels in the James River valley. Note how southeast-oriented Kelly Creek turns to flow northeast to join the south-oriented James River as a barbed tributary, even though a through valley continues south to the south-oriented James River. The through valley provides evidence water once flowed in multiple south-oriented channels and that headward erosion of the present day James River channel beheaded south-oriented flow in the parallel channels. Further, south-oriented water in the newly beheaded Kelly Creek channel reversed flow direction to flow northeast to the deeper James River channel rather than continuing south. Evidence of such reversals of flood flow are common throughout the Missouri River drainage basin and sometimes provide evidence of much larger scale flood flow reversals affecting what are today major Missouri River tributaries. Small lakes in the figure 6 map area probably provide evidence of melt water flood deposition of sediments around small ice masses that subsequently melted. This figure 6 map area is located is located on what was the Midcontinent Trench floor. The ice masses may have been stranded ice masses carried downstream by melt water floods prior to capture events that decreased flood flow in this Midcontinent Trench region. Once those ice masses became stranded flood waters may have continued to deposit sediments in the figure 6 map area even though flood flow was not great enough to move the stranded ice masses. Another possibility, as previously mentioned adjacent areas show evidence of wet based thin ice sheets covered the region and it is possible some of the figure 6 map area landscape features resulted from those wet based thin ice sheets.

Pipestem Creek-James River drainage divide area near Edmunds

Figure 7: Pipestem Creek-James River drainage divide area near Edmunds. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 7 illustrates the Pipestem Creek-James River drainage divide area near Edmunds, North Dakota and is located south of the figure 6 map area (and includes overlap areas with figure 6). The south-oriented James River valley is located along the figure 7 east edge. Pipestem Creek flows southeast from the figure 7 northwest corner to the figure 7 south center edge. Immediately west of Pipestem Creek is the northeast-facing Missouri Escarpment slope. At the Escarpment crest, along the figure 7 west edge (in the figure 7 southwest quadrant) is a small area of the Missouri Coteau. The Missouri Coteau is characterized by hummocky topography and small lakes as seen in figure 7. The Missouri Escarpment and the adjacent Missouri Coteau are landscape features that extend from east central Alberta southeast and south to southern South Dakota. For most of that distance the Missouri Escarpment is a rise from a lowland to the east or northeast to the higher level Missouri Coteau, which is a region covered by glacial moraines. In North Dakota and South Dakota the Missouri Coteau is located between the Missouri Escarpment and the Missouri River valley. The Missouri Escarpment and Missouri Coteau history are closely related to the history of a thick North American ice sheet (comparable in size and thickness to the present day Antarctic Ice Sheet) that rapidly melted. The thick North American ice sheet developed on a topographic surface now represented by high level Rocky Mountain erosion surfaces (if the topographic surface on which the thick North American ice sheet developed has been preserved at all). A deep North American “hole” was created by the thick ice sheet weight, which caused crustal down warping. In addition, deep glacial erosion probably further deepened ice sheet’s deep “hole”. The present day Pipestem Creek-James River drainage divide area was located on the former ice sheet floor, although it was not located in the deepest areas of the ice sheet’s deep “hole” (the Canadian Shield represents where the “hole” was deepest). Over time a considerable per cent of the ice sheet came to be located at elevations significantly below the ice sheet rim elevation, although a significant per cent of the ice sheet mass probably once stood high above the ice sheet rim elevation. Exactly where this ice sheet’s southwest rim was located probably cannot be determined, because the rim has since been deeply eroded by melt water flood erosion. At some point the thick ice sheet began to melt faster than new ice was being formed. The Missouri Escarpment and Missouri Coteau were formed during that thick ice sheet’s rapid melt down.

Pipestem Creek-James River drainage divide area south of Pingree

Figure 8: Pipestem Creek-James River drainage divide area south of Pingree. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 8 illustrates the Pipestem Creek-James River drainage divide south of the figure 7 map area near Pingree and is south of the figure 7 map area. Jim Lake is a reservoir located in the James River valley. Pipestem Creek flows southeast along the Missouri Escarpment base in the figure 8 west half. At the Missouri Escarpment crest small areas of the Missouri Coteau can be seen along the figure 8 west edge (southern two-thirds). Anastomosing channels east of the James River valley provides evidence the James River valley was eroded by a large-scale flood event. Small lakes or ponds in the lowland surface between Pipestem Creek and the James River may have formed when flood stranded ice masses melted (after flood waters deposited sediments around them). Hummocky topography and small lakes in the Missouri Coteau area provides evidence the Missouri Coteau region is probably underlain by glacial moraines. How did the thick ice sheet’s rapid melt down form the Missouri Escarpment and the Missouri Coteau? When the thick ice sheet rapid melt down began melt water rivers developed on the ice sheet surface. These supra-glacial rivers carved ice-walled and ice-floored valleys into the ice sheet surface, which eroded headward just as small gullies erode headward into unconsolidated clays. Over time some ice-walled and ice-floored river valleys developed extensive supra-glacial drainage networks. During periods of intense melting these supra-glacial rivers became immense melt water flood routes. Such melt water floods flowing to the ice sheet’s southern margin eventually flowed to the Gulf of Mexico and significantly eroded the landscape between the thick ice sheet’s southern margin and the Gulf of Mexico. In time melting progressed to the point where some ice-walled and ice-floored valleys became ice-walled and bedrock-floored valleys. One such giant ice-walled and bedrock-floored valley was carved by an immense southeast and south-oriented melt water river, named here as the Midcontinent River, which at its peak flowed from east central Alberta in a southeast direction through Saskatchewan to central North Dakota, where it turned to flow south to southern South Dakota. The Midcontinent River ice-walled and bedrock-floored valley (or canyon) is here named the Midcontinent Trench, and the Missouri Escarpment was eroded at the base of the Midcontinent Trench’s southwest and west wall.

James River valley east of Buchanan

Figure 9: James River valley east of Buchanan. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 9 illustrates the James River valley area east of Buchanan and east of the figure 8 map area (and includes overlap areas with figure 8). Jamestown Reservoir is located in the James River valley. East of the James River valley is a maze of channels, which provides evidence of a flood formed anastomosing channel complex. The anastomosing channels appear to have formed late in the figure 9 landscape development (i.e. they are cut into the prevailing topographic surface). The prevailing topographic surface includes small lakes and ponds suggesting ice masses were buried in flood water deposited sediments. There are also hummocky areas (e.g. in the figure 9 center) which suggest the possible presence of a glacial moraine. This area is located on the Midcontinent Trench floor, which means any glacial moraines located here are probably related to a glacial event subsequent to the thick ice sheet melt down. If so, the subsequent glacial event did not significantly affect the regional landscape (i.e. the Missouri Escarpment was not destroyed). At the time flood waters flowed southeast and south in this figure 9 region the Midcontinent Trench was probably an immense ice-walled and bedrock-floored canyon. This immense ice-walled and bedrock-floored canyon detached the thick ice sheet’s southwest margin. The detached ice sheet margin is named here as the Southwest Ice Sheet and its northeast edge was located at the Missouri Escarpment crest. The Southwest Ice Sheet was an immense ice wall between melt water floods moving along the Southwest Ice Sheet’s southwest margin and on the Midcontinent Trench valley floor to the east and northeast. In time the Southwest Ice Sheet melted and whatever debris contained within that detached ice mass was deposited forming the present day Missouri Coteau. Melt water flood erosion along the Southwest Ice Sheet’s southwest and west margin removed much of that debris, although closer to the Missouri Escarpment, where that ice marginal melt water flood erosion was not as intense, debris deposited by the melting Southwest Ice Sheet still remains. In places the ice-marginal floods broke through the Southwest Ice Sheet ice wall barrier and eroded ice-walled and bedrock-floored valleys to the lower Midcontinent Trench floor located to the northeast and east. The Missouri Coteau is located where the final Southwest Ice Sheet remnants melted.

Pipestem Creek-James River drainage divide area northwest of Jamestown

Figure 10: Pipestem Creek-James River drainage divide area northwest of Jamestown. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 10 illustrates the Pipestem Creek-James River drainage divide area northwest of Jamestown, North Dakota and south of figure 8 (and includes overlap areas with figure 8). Jamestown is located in the figure 10 southeast corner. Jamestown Reservoir is located in the James River valley and Pipestem Lake is located in the Pipestem Creek valley. Southeast-oriented Pipestem Creek joins the James River just south of figure 10 and the James River then makes a jog to the southeast before turning to flow south again. The Missouri Escarpment is located west of north-oriented Minneapolis Creek (in western Eldridge Township) and Pipestem Creek (north of where Minneapolis Creek joins it). The Missouri Escarpment slope in Windsor Township (figure 10 southwest quadrant) appears to be covered with glacial moraine materials, which is unusual for the Missouri Escarpment slope. The north-oriented Minneapolis Creek valley is linked south of figure 10 with a well-defined through valley to a large south-oriented valley (and probably to an anastomosing channel complex) that provides evidence the Minneapolis Creek originated as a south-oriented channel in what was a large-scale anastomosing channel complex located in the region east of the Missouri Escarpment. Anastomosing channel complexes during peak flood events are constantly changing and probably headward erosion of the southeast-oriented Pipestem Creek valley segment (between Minneapolis Creek and the present day James River valley) beheaded the south-oriented Minneapolis Creek flood flow channel. Flood waters on the north end of the newly beheaded Minneapolis Creek flood flow channel then reversed flow direction to flow north into the newly eroded and deeper Pipestem Creek valley. The Minneapolis Creek valley, Pipestem Creek valley, and James River valley appear to be the most recent figure 10 landscape features formed, which means a major south-oriented flood was the last major erosion event to affect the region. As previously mentioned it is possible there was a minor subsequent glacial event, although that glacial event did not significantly the figure 10 landscape.

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.