A geomorphic history based on topographic map evidence

The Little Missouri-North Fork Grand River drainage divide area is located in northwest South Dakota and southwest North Dakota, USA. Although detailed topographic maps of the Little Missouri-North Fork Grand River drainage divide area have been available for more than fifty years detailed map evidence has not previously been used to interpret the region’s geomorphic history. The interpretation provided here is based entirely on topographic map evidence. Based on the topographic map evidence the Little Missouri-North Fork Grand River drainage divide area is interpreted to have been eroded during immense flood events, the first of which flowed on a topographic surface at least as high as the highest points in the present-day drainage divide area. Flood erosion ended when headward erosion of the north and northeast-oriented Little Missouri River valley captured the southeast-oriented flood flow.

Preface:

The following interpretation of detailed topographic map evidence is provided as evidence in the Missouri River drainage basin landform origins research project, which is compiling similar evidence for all major drainage divides contained within the Missouri River drainage basin and for all major drainage divides with and within certain adjacent drainage basins. The research project is interpreting evidence in the context of a previously unexplored geomorphology paradigm, which is briefly described in the introduction below. Project essays are listed on the sidebar category list under their appropriate Missouri River tributary drainage basin, Missouri River segment drainage basin (by state), and/or state in which the Missouri River drainage basin is located.

Introduction:

• The purpose of this essay is to use topographic map interpretation methods to explore Little Missouri River-North Fork Grand River drainage divide area landform origins. 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 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 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 similar essays is a thick North American ice sheet, comparable in thickness to the present day Antarctic ice sheet, occupied approximately the North American region usually recognized to have been glaciated and through its weight and erosive actions created a “deep” North American “hole”, 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 Little Missouri River-North Fork Grand River drainage divide area landform evidence will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm.

Little Missouri-North Fork Grand River drainage divide area location

Figure 1: Little Missouri-North Fork Grand River drainage divide area and North Fork Grand River drainage basin (select and click in maps to enlarge). United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

The North Fork Grand River begins in southwest North Dakota and flows in a southeast direction into South Dakota where it joins the South Fork Grand River to form the Grand River.  The southeast-oriented North Fork Grand River drainage basin is located in southwest North Dakota and northwest South Dakota. West and northwest of the North Fork Grand River drainage basin is the north-oriented Little Missouri River valley and the north-oriented Deep Creek drainage basin (unnamed north-oriented Little Missouri River tributary flowing north of Rhame in figure 2). North of the North Fork Grand River drainage basin is the southeast-oriented Cedar Creek drainage basin, which flows eventually to the Cannonball River. South of the North Fork Grand River drainage basin are drainage basins of southeast-oriented tributaries flowing to the east-oriented South Fork Grand River. The North and South Forks of the Grand River join at the modern-day Shadehill Reservoir to form the southeast-oriented Grand River. East of the Little Missouri River valley many drainage routes shown in figure 1 have a remarkable southeast orientation. This southeast-oriented drainage alignment suggests erosion of the entire region by a common southeast-oriented flood event. The north-oriented Little Missouri River appears to have beheaded southeast-oriented flood flow moving to the present-day headwaters of the southeast-oriented drainage routes. This beheading of the southeast-oriented drainage routes can be explained by headward erosion of a north-oriented Little Missouri River valley headcut during the southeast-oriented flood event. Evidence in the Little Missouri-North Fork Grand River drainage divide area to support these interpretations will be investigated in the following essay. Additional evidence is discussed in essays related to the North fork Grand River drainage basin and adjacent drainage basins.

Rhame area through valleys

Southeast-oriented figure 2 streams flow to the North Fork Grand River, north of the highway northwest-oriented streams flow to north-oriented Deep Creek and eventually the north-oriented Little Missouri River and south of the highway the west-oriented streams flow to the north-oriented Little Missouri River. Multiple through valleys can be seen connecting all three drainage basins suggesting the region was eroded by an immense southeast-oriented flood that was systematically captured by headward erosion of headcuts in each of the three drainage basins. Headward erosion of the deep southeast-oriented North Fork Grand River valley evolved as it and its associated tributary headcuts progressively captured the southeast-oriented floodwaters southeast of the map area. Headward erosion of the deep north-oriented Little Missouri River valley headcut and its tributary deep north-oriented Deep Creek headcut then progressively captured the southeast-oriented floodwaters north of the map area and flood flow on the northwest ends of beheaded southeast-oriented flood flow routes was reversed to produce northwest-oriented Deep Creek tributaries like those in figure 2. Continued headward erosion of the deep north-oriented Little Missouri River valley headcut west of the map area beheaded southeast-oriented flood flow across the map area and floodwaters on the northwest ends of the beheaded flood flow routes reversed direction to flow west and northwest back to the newly eroded deeper Little Missouri River valley headcut. Present-day through valleys linking the three drainage basins are remnants of the southeast-oriented anastomosing channel complex eroded by the southeast-oriented floodwaters before dismemberment by deep headcut erosion.

Medicine Pole Hills through valleys

Figure 3: Medicine Pole Hills through valleys. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

The Little Missouri River-North Fork Grand River drainage divide south of Rhame crosses the Medicine Pole Hills. Northwest of the Medicine Pole Hills drainage flows northwest to the north-oriented Little Missouri River. Southeast of the Medicine Pole Hills drainage flows to southeast-oriented North Fork Grand River tributaries.  Cold Turkey Creek and other unnamed North Fork Grand River tributaries begin at what are interpreted to be abandoned southeast-oriented headcuts carved into the Medicine Pole Hills upland, suggesting erosion of those southeast-oriented valleys was initiated by immense volumes of southeast-oriented flood water eroding deep southeast-oriented headcuts into a topographic surface at least as high as the tops of the present-day Medicine Pole Hills. These deep headcuts eroded northwest until they reached more resistant rock in the Medicine Pole Hills area. Southeast-oriented floodwaters from adjacent flood flow routes spilling over into the newly eroded deep southeast-oriented headcuts were able to carve deep tributary headcuts around the resistant rock masses and also erode the surrounding region. Note how through valleys linking the southeast-oriented headcut basins with northwest-oriented Little Missouri tributary headwaters enter the southeast-oriented headcut basins from the sides. Southeast-oriented flood flow through the Medicine Pole Hills area ended when headward erosion of the north-oriented Little Missouri River valley headcut captured the southeast-oriented flood flow. Southeast-oriented floodwaters already between the Little Missouri River valley and the Medicine Pole Hills area reversed direction and flowed in a northwest direction to carve the present-day northwest-oriented Little Missouri River tributaries.

Anastomosing channels south of the Medicine Pole Hills

Figure 4: Anastomosing channels south of the Medicine Pole Hills. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Continuing south from the Medicine Pole Hills along the Little Missouri River-North Fork Grand River drainage divide multiple northwest to southeast oriented through valleys link headwaters of the southeast-oriented North Fork Grand River tributaries with headwaters of northwest-oriented Little Missouri River tributaries. Skull Creek is the major northwest-oriented tributary draining the area. Like other Little Missouri River-North Fork Grand River drainage divide segments to the north and south, the drainage divide segments shown in figure 4 is crossed by northwest to southeast oriented through valleys. Through valleys crossing the drainage divide have different elevations, and the multiple through valleys can only be explained if southeast-oriented floodwaters initially flowed over the entire region. As deeper through valleys were eroded the southeast-oriented flood flow probably was concentrated in those deeper channels, although even then the flood flow would have been moving in an immense anastomosing complex of southeast-oriented channels. The present-day Little Missouri River-North Fork Grand River drainage divide originated when headward erosion of the north-oriented Little Missouri River valley headcut systematically beheaded the southeast-oriented flood flow moving to the North Fork Grand River drainage basin and caused a reversal of flood flow on the northwest ends of the beheaded southeast-oriented flood flow routes. The reversals of flood flow to newly eroded deep Little Missouri River valley headcut eroded the valleys of the present-day northwest-oriented Little Missouri River tributaries. Floodwaters moving on yet to be beheaded southeast-oriented flood flow routes probably spilled over to join reversed flood in the beheaded routes to help eroded the northwest-oriented valleys.

Horse Creek-North Fork Grand River through valley

Figure 5: Horse Creek-North Fork Grand River through valley. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Continuing still further south along the Little Missouri River-North Fork Grand River drainage divide figure 5 illustrates more through valleys crossing the drainage divide. The most prominent through valley in figure 5 links southeast-oriented North Fork Grand River headwaters with northwest-oriented Horse Creek headwaters flowing to the north-oriented Little Missouri River. Other less prominent through valleys link other southeast-oriented drainage routes with northwest-oriented drainage routes, both in figure 5 and in adjacent areas both north and south (see figures 2, 3, 4, and 6) and suggest all through valleys were carved as part of an immense southeast-oriented flood eroded anastomosing channel complex. Through valleys are carved between what are today the highest points along the drainage divide suggesting the floodwaters originally flowed on a topographic surface at least as high as those present-day high points and that flood water erosion lowered the surrounding landscape. Southeast-oriented flood flow in this southeast-oriented anastomosing channel complex was systematically beheaded from north to south by headward erosion of the deep north-oriented Little Missouri River valley headcut. As southeast-oriented flood flow routes were beheaded, floodwaters on the northwest ends of those beheaded flood flow routes reversed direction to flow back to the newly eroded deep Little Missouri River valley headcut. That reversal of flow created the present-day Little Missouri River-North Fork Grand River drainage divide also eroded the northwest-oriented Little Missouri River tributary valleys. Erosion of those northwest-oriented tributary valleys was aided by capture and reversal of flood water still moving southeast on yet to be beheaded southeast-oriented flood flow routes.

Fivemile and Sevenmile Creek-Lone Tree Creek through valleys

Figure 6: Fivemile and Sevenmile Creek-Lone Tree Creek through valleys. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Continuing south along the Little Missouri River-North Fork Grand River drainage divide to the North Dakota-South Dakota border we encounter still more northwest to southeast oriented through valleys. It is difficult to explain these multiple through valleys unless they were eroded as components of a southeast-oriented anastomosing channel complex. Such a southeast-oriented anastomosing channel complex was carved during an immense southeast-oriented flood event. Present-day through valleys and their linkages to northwest and southeast-oriented valley outline that flood eroded anastomosing channel complex. Through valleys today have different elevations and map evidence suggests floodwaters originally moved on a topographic surface at least as high as the tops of the present-day hills. Remember, the northwest to-southeast oriented through valleys are present for the entire length of the Little Missouri-North Fork Grand River drainage divide, meaning southeast-oriented floodwaters flowed across the entire region. The present-day drainage divide was created when the north-oriented Little Missouri River valley eroded south and systematically beheaded southeast-oriented flood flow routes. Floodwaters on the northwest ends of beheaded southeast-oriented flood flow routes reversed direction to flow back into the newly eroded deep Little Missouri River valley headcut. The reversed flow, augmented by captures of southeast-oriented flood flow from yet to be beheaded flood routes, eroded the present-day northwest-oriented tributary valleys and created the drainage divide.

Headwaters of Lone Tree Creek and Crooked Creek

Figure 7: Headwaters of Lone Tree Creek and Crooked Creek. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Continuing still further south from figure 6 the major North Fork Grand River tributaries are the northeast-oriented Lone Tree Creek and Crooked Creek as shown in figure 7. The westernmost southeast-oriented Lone Tree Creek tributaries are linked by through valleys to northwest oriented Little Missouri River tributaries. West of the forested North Cave Hills upland southeast-oriented Crooked Creek tributaries are linked by through valleys to northwest-oriented Lone Tree Creek tributaries. East of the North Cave Hills upland is the Pete’s Creek drainage basin where Pete’s Creek flows northeast, northwest and then northeast to Crooked Creek. Note the northwest-oriented Fuller Canyon valley cut across the North Cave Hills upland. Southeast-oriented drainage routes south and west of Table Mountain flow to the South Fork Grand River and are linked by through valleys to west and northwest oriented Little Missouri River tributaries. A deep southeast-oriented escarpment surrounded basin or headcut is located immediately southeast of Table Mountain and drains to the southeast-oriented Middle Creek and eventually the South Fork Grand River.  The aligned drainage routes and through valleys and the elbows of capture where southeast-oriented flow has been captured by northeast-oriented headcuts all support the interpretation that the North Fork Grand River drainage basin area shown in figure 7, like areas shown in other North Fork Grand River drainage basin figures, was eroded by an immense southeast-oriented flood. The figure 7 evidence suggests this immense flood first flowed on a topographic surface at least as high as the present-day highest upland surfaces (North Cave Hills and Table Mountain upland surfaces) and was responsible for removal of bedrock surrounding the modern-day residual uplands

Crooked Creek and Bull Creek at North Cave Hills

Figure 8: Crooked Creek and Bull Creek at North Cave Hills. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 8 looks at the North Cave Hills region. The southeast-oriented stream in the southwest of the forested upland is Bull Creek flowing to the South Fork Grand River. Crooked Creek and its tributaries drain the area northwest of upland while Pete’s Creek, a Crooked Creek tributary, drains the area east of the upland. How could a large southeast-oriented flood erode the regional landscape to produce the present-day drainage pattern? The flood involved must have been so great it eroded a southeast-oriented system of headcuts and tributary headcuts that were 100 meters or more deep and 10 kilometers or more in width headward across the region. The North Fork Grand River drainage basin evolved as one such gigantic southeast-oriented headcut system eroded headward. The tributary Crooked Creek headcut eroded southwest, west and southwest, with the Pete’s Creek headcut eroding as a southwest-oriented tributary headcut (the parallel Lone Tree Creek headcut eroded north and west of the Crooked Creek headcut to behead the southeast-oriented flood flow—see figure 7). The South Fork Grand River drainage basin evolved in a similar manner and the southeast-oriented Bull Creek headcut eroded northwest to capture flood water that had been moving to the newly eroded deep Crooked Creek headcut. Headward erosion of the deep Little Missouri River valley headcut beheaded flood flow to both the North Fork and South Fork of the Grand River and modern-day river valleys formed as floodwaters on beheaded flood flow routes drained either southeast-or northwest and created the present-day Little Missouri River-Grand River drainage divide.

Beheading of Camel Creek near Table Mountain

Figure 9: Beheading of Camel Creek near Table Mountain. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 9 illustrates details of the area immediately southeast of Table Mountain. Note the large southeast oriented escarpment surrounded basin or headcut eroded into the Table Mountain upland. The southeast oriented stream originating in that basin is Middle Creek, which flows to Bull Creek and the South Fork Grand River. In the south half of section 14 an east-northeast oriented stream, Camel Creek, flows to Crooked Creek and the North Fork Grand River. The east-northeast oriented Camel Creek valley has been beheaded by the deeper southeast- oriented Middle Creek valley. At the time of the beheading floodwaters for a time had to be flowing both southeast to the South Fork Grand River and east-northeast to the North Fork Grand River. Since the North and South Forks join downstream to form the Grand River this evidence demonstrates both the North Fork and the South Fork were headcuts eroded as channels of a gigantic anastomosing channel complex encompassing the entire region (and probably much more). The present-day Table Mountain elevation and the Middle Creek headcut depth provide a minimum estimate of the depth of the immense flood carved headcuts that eroded headward across the region. The headcuts were eroded into a topographic surface at least as high as the present-day Table Mountain top. Through valleys carved in the Middle Creek headcut basin side walls were eroded by flood water spilling around the Table Mountain resistant cap rock mass to reach the deep headcut face and also by Camel Creek tributary valley headcuts that for a time carried floodwaters from the headcut face to the deep Camel Creek headcut. Floodwaters moving around the Table Mountain resistant cap rock mass stripped the surrounding to leave Table Mountain as a modern-day monadnock.

Summary of Little Missouri-North Fork Grand River drainage divide area evidence

• The North Fork Grand River begins in North Dakota and flows in a southeast direction into South Dakota where it joins the South Fork Grand River to form the Grand River. East-oriented North Fork Grand River headwaters are located along the north-oriented Little Missouri River drainage basin east edge. Multiple northwest to southeast oriented through valleys link southeast-oriented North Fork Grand River headwaters with northwest-oriented Little Missouri River tributaries. This evidence suggests southeast-oriented floods flowed across the drainage divide and eroded the southeast-oriented North Fork Grand River drainage basin. Further, this evidence also suggests flood flow to the North Fork Grand River drainage basin was beheaded when the deeper north-oriented Little Missouri River valley headcut and its tributary Deep Creek headcut eroded south.

• Evidence suggests the North Fork Grand River valley and its tributary valleys originated as channels in an anastomosing channel complex that included both the North Fork and the South Fork drainage basins. North Fork tributaries beheaded southeast-oriented flood flow moving to the South Fork drainage basin area and at least one northeast-oriented North Fork tributary was beheaded by headward erosion of a deeper South Fork tributary valley. Since the North and South Forks join downstream to form the Grand River such beheading of each other’s drainage areas requires that for a time at least water from the point where the beheading took place could follow two quite different routes to the downstream Grand River valley. That is the way an anastomosing channel complex works.

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 the detailed 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 were created using National Geographic 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.