A geomorphic history based on topographic map evidence

The North Fork-South Fork Grand River drainage divide area is located in northwest South Dakota, USA. Although detailed topographic maps of the North Fork-South 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 North Fork-South 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 northwest South Dakota North Fork Grand River-South 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 northwest South Dakota North Fork Grand River-South Fork Grand River drainage divide area landform evidence will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm.

North Fork-South Fork Grand River drainage divide location map

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

The North Fork-South Fork Grand River drainage divide is located in Harding and Perkins Counties in the northwest corner of South Dakota, however the North Fork Grand River drainage basin also includes areas of adjacent Bowman and Adams Counties, which are located in the southwest corner of North Dakota.  Immediately west of Harding and Bowman Counties is the state of Montana. The North Fork Grand River begins in Bowman County, North Dakota and flows in a southeast-oriented direction to join the South Fork Grand River at Shadehill Reservoir in Perkins County, South Dakota (see east center figure 1). A major northeast-oriented North Fork Grand River tributary, Crooked Creek, originates in the area of Table Mountain (west of the northernmost Custer National Forest area) and flows in an east and northeast direction to join the North Fork Grand River near the North Dakota-South Dakota state line. A different essays illustrates and discusses the North Fork Grand River drainage basin landform origins and can be found under SD Grand River on the sidebar category list. South Fork Grand River headwaters are located in western Harding County and while there are many southeast-oriented tributaries from the north, the South Fork Grand River flows in an easterly direction and then turns northeast to join the North Fork Grand River at Shadehill Reservoir. West of the North Fork and South Fork Grand River is the north-oriented Little Missouri River. Other essays illustrate and discuss the Little Missouri River-North Fork Grand River drainage divide area and the Little Missouri River-South Fork Grand River drainage divide area and can be found under Little Missouri River on the sidebar category list. This essay illustrates and discusses North Fork-South Fork Grand River drainage divide area landform evidence.

• The figure 1 big picture map illustrates the relationship of the southeast and east oriented North and South Grand River headwaters to the north-oriented Little Missouri River. As discussed in other essays on this website the Little Missouri-Grand River drainage divide is an asymmetric drainage divide indicating the Little Missouri River valley eroded south to behead and capture multiple flow routes that once carried large amounts of water from the west and northwest of the figure 1 map area into the present-day Grand River drainage basin.  Also visible in figure 1 is the northwest-southeast alignment of North and South Fork Grand River tributaries. This northwest-southwest drainage alignment is evidence the east and northeast-oriented South Fork Grand River eroded headward across multiple southeast-oriented flood flow routes, capturing the flood water and diverting it east and northeast to what is to the Grand River valley east of the Shadehill Reservoir. The existence of multiple flow routes across what is today the Little Missouri River-Grand River drainage divide suggests captures took place during an immense southeast-oriented flood event, with the floodwaters being responsible for erosion of the North and South Fork Grand River drainage basins and also for erosion of the north-oriented Little Missouri River drainage basin.This knol will look for additional southeast-oriented flood flow evidence along the North Fork-South Fork Grand River drainage divide and will start in the west and proceed east.

North Fork-South Fork Grand River drainage divide in Table Mountain area

Figure 2: North Fork-South Fork Grand River drainage divide in the Table Mountain area. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 2 illustrates the North Fork-South Fork Grand River drainage divide where the north-oriented Little Missouri River drainage basin truncates it. Northwest-oriented streams along the figure 2 west edge flow to the north-oriented Little Missouri River. The northeast-oriented Lone Tree Creek drainage basin (north center of figure 2) and the Crooked Creek drainage basin (east center) are included in the North Fork Grand River drainage basin, while the southeast-oriented Bull Creek drainage basin, including the Middle Creek and Campbell Creek drainage basins, are included in the South Fork Grand River drainage basin. What is particularly interesting about the figure 2 map evidence is how northeast-oriented Lone Tree Creek and Crooked Creek segments appear to have captured multiple southeast-oriented tributaries. Lone Tree Creek also has northwest-oriented tributaries suggesting reversal of flow on what were probably the northwest ends of beheaded southeast-oriented flow routes. This evidence suggests headward erosion of the Crooked Creek valley headcut captured southeast-oriented flow moving to the South Fork Grand River drainage basin. However, the situation is more complicated because southeast of Table Mountain there is evidence headward erosion of the Middle Creek valley beheaded northeast-oriented valleys used by Staadt and Camel Creek headwaters. In other words, while headward erosion of the North Fork Grand River drainage basin captured southeast-oriented flow on multiple flow that was moving to the South Fork Grand River drainage basin, headward erosion of deeper southeast-oriented South Fork Grand River tributary valleys beheaded northeast-oriented North Fork Grand River tributary valleys. Further, looking at the big picture map in figure 1 we see both the North and South Forks Grand River come together at Shadehill Reservoir. This situation is best explained in the context of a large-scale and ever-changing anastomosing channel complex of the type that might form during an immense southeast-oriented flood that was systematically being captured by headward erosion of a deeper east-oriented anastomosing channel complex. Figure 2 also provides evidence the southeast-oriented floodwaters first flowed over a topographic surface at least as high as the map region’s highest elevations. For example, southeast-oriented Middle Creek originates in an escarpment-surrounded basin located on the Table Mountain southeast side. That southeast-oriented escarpment-surrounded basin appears to be an abandoned headcut eroded by large volumes of water flowing southeast across what is today the Table Mountain top. Close study of stream captures demonstrates headward erosion by what is today the abandoned headcut ceased when flood flow that had been flowing across the Table Mountain top was systematically captured and diverted to flow around the present-day Table Mountain upland, where deep valleys were eroded, and then headward erosion of the Lone Tree Creek drainage basin captured the flow.

North Fork-South Fork Grand River drainage divide in North Cave Hills area

Figure 3: North Fork-South Fork Grand River drainage divide in North Cave Hills area. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Continuing east along the North Fork-South Fork Grand River drainage divide we next reach the North Cave Hills area illustrated in figure 3. Crooked Creek and its various tributaries are in the North Fork Grand River drainage basin. In the figure 3 southwest corner Campbell Creek flows to the (unnamed) southeast-oriented Bull Creek, which flows to the South Fork Grand River. South of the Tepee Buttes area (northeast corner figure 3) is the southeast-oriented Big Nasty Creek drainage basin, which drains to the east-oriented South Fork Grand River. Figure 3 drainage patterns provide evidence northeast-oriented Crooked Creek and Crooked Creek tributaries have captured southeast-oriented flow routes that once flowed to the South Fork Grand River drainage basin. For example, Petes Creek has a northwest-oriented segment and also a northwest-oriented tributary (center figure 3) both of which represent reversed flow on segments of a beheaded southeast-oriented flow route. Northwest-southeast oriented Fuller Canyon provides evidence southeast-oriented flow once moved on a topographic surface at least as high as the present-day North Cave Hills highest elevations and subsequently eroded a deep narrow valley before Crooked Creek valley headward erosion beheaded and captured the southeast-oriented flow. Southwest-oriented Schleichart Draw provides evidence the southwest end of a higher level northeast-oriented stream (a higher level Petes Creek?) was captured and reversed by headward erosion of the deep Bull Creek-Middle Creek-Campbell Creek valley complex, although subsequent erosion has removed most evidence of that earlier channel system. In addition to evidence that North Fork Grand River tributaries captured southeast-oriented flood water moving to the South Fork Grand River drainage basin, and a hint South Fork Grand River tributaries captured flood flow flowing to the North Fork Grand River drainage basin, there is also evidence South Fork Grand River tributaries were capturing southeast-oriented flood flow moving to other South Fork Grand River tributaries. For example, south of Riley’s Butte (figure 3 enter) Big Nasty Creek headwaters eroded west to capture southeast-oriented that probably was moving to the North Jack Creek drainage basin. Again this evidence for multiple capture events suggests the types of captures that occur in an ever-changing flood eroded anastomosing channel complex, in which the flood waters were flowing over the entire North Fork-South Fork Grand River drainage basin area.

Crooked Creek-Big Nasty Creek drainage divide area

Figure 4: Crooked Creek-Big Nasty Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Moving a bit further east along the North Fork-South Fork Grand River drainage divide figure 4 provides a better view of the Crooked Creek-Big Nasty Creek drainage divide. Crooked Creek flows northeast to the southeast-oriented North Fork Grand River while Big Nasty Creek flows southeast to the east-oriented South Fork Grand River. Big Nasty Creek tributaries are aligned in a northwest-southeast direction and probably reflect the direction flood waters were moving at the time flood flow to the Big Nasty Creek drainage basin was beheaded by headward erosion of the deeper northeast-oriented Crooked Creek valley headcut. Northwest and southeast-oriented Crooked Creek tributaries provide further evidence of this aligned drainage pattern and are likewise relics of the southeast-oriented flood flow that was moving across the region at the time the large Crooked Creek valley headcut was eroded southwest and west. Again, the multiple channels suggest the presence of multiple flood flow routes or some type of southeast-oriented anastomosing channel complex that was being captured by a deeper anastomosing channel complex with a more easterly orientation.

Lodge Pole Buttes area

Figure 5: Lodge Pole Buttes area. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Proceeding a bit further east along the North Fork-South Fork Grand River drainage divide we come to the Lodge Pole Buttes area shown in figure 5. Big Nasty Creek is the stream flowing southeast across the figure 5 southwest corner. North-northwest-oriented oriented tributaries along the figure 5 north edge flow to the southeast-oriented North Fork Grand River, which is located north of the figure 5 map area. Note south-southeast oriented tributaries flowing to Big Nasty Creek. Southeast-oriented Horse Creek (northeast quadrant figure 5) after flowing southeast turns north and north-northwest at pronounced elbow of capture (seen in figure 6) and flows to the North Fork Grand River. Fivemile Creek in the figure 5 southeast corner flows south to  southeast-oriented Big Nasty Creek. Figure 5 evidence suggests previous drainage across the Lodge Pole Buttes area flowed in multiple south-southeast channels and was captured by headward erosion of the southeast-oriented Big Nasty Creek valley and was being in the process of being captured by the southeast-oriented Horse Creek valley, but Horse Creek valley headward erosion ceased because headward erosion of the southeast-oriented North Fork Grand River valley north of the figure 5 map area beheaded and captured the south-southeast oriented flood flow. The north-northwest oriented North Fork Grand River tributaries were developed by reversals of flow on what were the north-northwest ends of the beheaded south-southeast oriented flood flow routes. Lodge Pole Buttes has an arcuate shape and forms a southeast-facing escarpment-surrounded basin, which suggests southeast-oriented floodwaters once flowed on a topographic surface at least as high as the Lodge Pole Buttes highest elevation and eroded a southeast-oriented headcut valley into the Lodge Pole Buttes bedrock mass. Subsequently floodwaters were captured by flow routes that were able to erode deeper and faster on either side of the what are today the Lodge Pole Buttes and eventually the surrounding bedrock was removed leaving Lodge Pole Buttes as an isolated monadnock today.

Horse Creek-Lodgepole Creek drainage divide area

Figure 6: Horse Creek-Lodgepole Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Our journey east along the North Fork-South Fork Grand River drainage divide continues with figure 6, which illustrates the Horse Creek elbow of capture (northwest quadrant). Figure 5 showed southeast-oriented Horse Creek headwaters and at the elbow of capture shown here in figure 6 Horse Creek makes an abrupt turn from its former southeast-orientation to flow north to the southeast-oriented North Fork Grand River located north of figure 6 map area. Immediately southeast of the present-day Horse Creek elbow of capture are a series of northwest-oriented Horse Creek tributaries. These northwest-oriented tributaries were formed by reversals of flow on the northwest ends of multiple southeast-oriented flood routes that were beheaded when the deep Horse Creek valley headcut eroded south. These multiple northwest-oriented tributaries provide evidence that prior to the deep Horse Creek headcut headward erosion, southeast-oriented flood flow on the Horse Creek alignment was moving in multiple channels, not in a single channel as it does today. Southeast of the northwest-oriented Horse Creek tributaries is a southeast-oriented escarpment-surrounded upland plateau, which is drained to the southeast by southeast-oriented Lodgepole Creek, which flows to the northeast-oriented South Fork Grand River segment. The Lodgepole Creek escarpment-surrounded upland northwest face was created when the deep north-oriented Horse Creek segment valley eroded south from the deep North Fork Grand River to behead and capture what must have been multiple southeast-oriented flood flow routes responsible for eroding the Lodgepole Creek upland surface. The escarpment-surrounded upland north-facing escarpment had been previously eroded by earlier south-oriented valley headcuts that eroded south from the deep southeast-oriented North Fork Grand River valley. The upland’s south-facing escarpment was eroded by headward erosion of southeast-oriented Duck Creek (south center), which flows to the east and northeast-oriented South Fork Grand River. Note multiple through valleys linking the Horse Creek drainage basin with the Duck Creek drainage basin. These through valleys are evidence water once flowed southeast from what is today the Horse Creek drainage basin to what is today the Duck Creek drainage basin, although when that flow occurred the deep Horse Creek and Duck Creek valleys did not exist.

Lodgepole Creek escarpment-surrounded upland

Figure 7: Lodgepole Creek escarpment-surrounded upland. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 7 continues our view of the North Fork-South Fork Grand River drainage divide by illustrating an area slightly further east than the figure 6 map area. Lodgepole Creek drains the Lodgepole Creek escarpment-surrounded upland in a southeast direction to the northeast-oriented South Fork Grand River segment. The North Fork Grand River is flowing southeast at the northeast corner of figure 7. The northeast-facing escarpment, which serves as the North Fork-South Fork Grand River drainage divide, is immediately northeast of southeast-oriented Lodgepole Creek. Note how an unnamed northeast-oriented North Fork Grand River tributary flowing to Vobejda Lake (north edge figure 7 on east side of the north-south highway) has captured southeast-oriented tributaries and how 3 miles south of Vobejda Lake are  headwaters of an unnamed east-southeast oriented stream that turns at an elbow of capture northeast to join the southeast-oriented North Fork Grand River. These North Fork Grand River tributaries and others provide evidence that as the deep North Fork Grand River valley headcut eroded northwest, tributary headcuts eroded south and southwest to systematically capture southeast-oriented flood waters that were flowing on flood flow routes between the present-day North Fork Grand River route and the present-day Lodgepole Creek route. This evidence can be best explained in the context of floodwaters covering the entire region and flowing southeast in an ever-changing anastomosing channel complex that was systematically being captured by headward erosion of the deep North Fork and South Fork Grand River valley headcuts and their various tributary valley headcuts.

North Fork Grand River-Lodgepole Creek drainage divide west of Shadehill Reservoir

Figure 8: North Fork Grand River-Lodgepole Creek drainage divide west of Shadehill Reservoir. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 8 almost completes our eastward journey along the North Fork-South Fork Grand River drainage divide. The North Fork Grand River flows in an east-southeast-oriented direction across the  figure 8 map area north edge. The northeast-oriented South Fork Grand River is in the figure 8 southeast corner. Lodgepole Creek flows east-southeast across the figure 8 center and joins the northeast-oriented South Fork Grand River. The Shadehill Reservoir arms extending up the North Fork and South Fork valleys are seen along the figure 8 east edge. Note unnamed southeast-oriented tributaries and northwest-oriented tributaries flowing to the northeast-oriented South Fork Grand River valley. This aligned drainage provides evidence the deep northeast-oriented South Fork Grand River valley eroded headward (or southwest) across multiple southeast-oriented flood routes. In other words, the deep South Fork Grand River valley was eroded headward before the more northerly Lodgepole Creek and North Fork Grand River valley headcuts could erode west and northwest to behead and capture those southeast-oriented flood flow routes. Also note the North Fork-South Fork Grand River drainage divide area between Lodgepole Creek and the North Fork Grand River. Through valleys link the Lodgepole Creek and North Fork Grand River valleys. These through valleys are evidence that even as the Lodgepole Creek and North Fork Grand River valleys were being eroded, floodwaters were spilling from one valley to the other. Figure 9 below illustrates a detail map of the through valley extending north from the blue word “Creek” in “Lodgepole Creek” shown in the figure 8 center.

Detail map of the North Fork Grand River-Lodgepole Creek drainage divide

Figure 9: Detail map of the North Fork Grand River-Lodgepole Creek drainage divide. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 9 illustrates a detail map of a through valley linking the Lodgepole Creek and North Fork Grand River valleys. The location of this through valley is identified at the figure 8 discussion conclusion. The east-southeast-oriented North Fork Grand River is in the figure 9 northeast corner. The southeast-oriented Lodgepole Creek is in the figure 9 southwest corner. The through valley extends from the Lodgepole Creek valley in a north-northwest direction in the figure 9 center. This south-southeast-oriented through valley was probably eroded as a tributary to the deep southeast-oriented Lodgepole Creek valley that was being eroded northwest (from a newly eroded northeast-oriented South Fork Grand River valley) to capture south-southeast-oriented flood routes the North Fork Grand River valley headward erosion had yet to behead and capture. South-southeast oriented flow on this newly formed Lodgepole Creek tributary was subsequently beheaded and captured by headward erosion of the deeper North Fork Grand River valley headcut. Once beheaded flood water contained within the through valley northern segment reversed flow direction and carved the north-oriented unnamed North Fork Grand River tributary valley located in section 18 (north center figure 9). A close look at figure 9 reveals many additional complications this simplistic explanation does not address, although these complications can probably be explained in the flood interpretation context. Hopefully the simplistic explanation provides clues that can help further unravel the complex pattern of anastomosing channels that carved this landscape as deeper east-oriented channels eroded headward to capture southeast-oriented floodwaters flowing across this North Fork-South Fork Grand River drainage divide region.

North Fork-South Fork Grand River confluence area at Shadehill Reservoir

Figure 10: North Fork-South Fork Grand River confluence area at Shadehill Reservoir. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 10 illustrates the Shadehill Reservoir area or North Fork-South Fork Grand River confluence area and completes out trip eastward along the North Fork-South Fork Grand River drainage divide. The Grand River can be seen flowing east downstream from the Shadehill Reservoir dam. Eventually the Grand River  reaches the south-oriented Missouri River. Figure 10 provides a better view of the multiple southeast and northwest-oriented tributaries flowing to the northeast-oriented South Fork Grand River. As previously discussed these aligned tributaries provide evidence the deep South Fork Grand River valley eroded headward across multiple southeast-oriented flood flow routes that had not yet been beheaded and captured by headward erosion of the deep east-southeast-oriented Lodgepole Creek valley or by the subsequent headward erosion of the deep east-southeast-oriented North Fork Grand River valley. And again, the northwest-oriented tributary valleys were eroded by reversed flood on the northwest ends of the beheaded southeast-oriented flood flow routes. This evidence for multiple southeast-oriented flow channels is just a continuation of similar evidence we have seen all along the North Fork-South Fork Grand River drainage divide. What we have seen is evidence the North Fork Grand River valley and the South Fork Grand River valley were eroded headward as components of an immense east-oriented (and northeast-oriented, although evidence for the northeast-orientation was not seen) anastomosing channel complex that was capturing southeast-oriented floodwaters.

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.