A geomorphic history based on topographic map evidence

The Powder River-Cheyenne River drainage divide area is located in the Wyoming Powder River Basin, USA. Although detailed topographic maps of the Powder River-Cheyenne 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. The Powder River-Cheyenne River drainage divide area is interpreted to have been eroded during immense southeast-oriented 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 today. Flood flow across the Powder River-Cheyenne River drainage divide area ended when deep Powder River valley headward erosion captured all southeast-oriented flood flow.

Introduction:

• The purpose of this essay is to use topographic map interpretation methods to explore Wyoming Powder River-Cheyenne 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 essay 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 Wyoming Powder River-Cheyenne River drainage divide area landform evidence will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm.

Powder River-Cheyenne River drainage divide area general location map

Figure 1: Powder River-Cheyenne River drainage divide area general 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 general location map for the Powder River-Cheyenne River drainage divide area. The North Fork Powder River begins near Powder River Pass (figure 1 northwest quadrant) and flows southeast to Kaycee, Wyoming where it joins the northeast oriented Middle Fork Powder River. The combined North and Middle Forks then flow east to join the northeast oriented South Fork Powder and the Powder River then flows northeast and north to the figure 1 north edge. Powder River tributaries from the east shown in figure 1 are northwest-oriented. Clear Creek and Crazy Woman Creek are Powder River tributaries from the west that flow east from the Bighorn Mountains and then turn northeast to join the north-oriented Powder River. Other essays found under Powder River on the sidebar category list address Clear Creek-Powder River and Crazy Woman Creek-Powder River drainage divide evidence. Salt Creek is the unnamed northwest-oriented Powder River tributary flowing through Edgerton, Wyoming (figure 1 center) and will be important in this essay. The Dry Fork of the Cheyenne River originates southeast of Teapot Dome (figure center) and flows northeast to the Cheyenne River, which then flows southeast around the Black Hills south end before turning northeast again. North of the Dry Fork Cheyenne River are northeast oriented headwaters and tributaries to Antelope Creek, which flows to the Cheyenne River, and southeast of the Dry Fork is the northeast-oriented Lightning Creek drainage system, which also flows to the Cheyenne River. North of Antelope Creek and the Cheyenne River itself all Cheyenne River tributaries shown in figure 1 are southeast oriented. The Belle Fourche River originates west of Wright, Wyoming and flows northeast between the Powder River and Cheyenne River drainage basins. Essays found under Belle Fourche River on the sidebar category list address Powder River-Belle Fourche River drainage divide evidence and Wyoming’s Belle Fourche River-Cheyenne River drainage divide area evidence. This essay interprets Powder River-Cheyenne River drainage divide evidence in the context of an immense flood, with flood waters moving southeast through the Wyoming Powder River Basin (between the Bighorn Mountains and Black Hills) and also east and northeast around the Bighorn Mountain south end. The southeast-oriented flood flow was captured by headward erosion of the Cheyenne River valley and diverted around the Black Hills south end and then northeast. Headward erosion of the Cheyenne River valley also captured some of the east and northeast-oriented flood flow. Flood flow to what was then the actively eroding Cheyenne River valley was beheaded by headward erosion of the northeast- and north-oriented Powder River-South Fork Powder River valley and the water was diverted further to the north.

Powder River-Cheyenne River drainage divide area detailed location map

Figure 2: Powder River-Cheyenne River drainage divide area detailed location map. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 2 provides a detailed location map for the Powder River-Cheyenne River drainage divide area. The figure 2 northeast county is Campbell County, Wyoming, the northwest county is Johnson County, the southeast county is Converse County, and the southwest county is Natrona County. The North Fork Powder River flows southeast from the figure 2 northwest corner to join the northeast-oriented Middle Fork Powder River east of Kaycee, Wyoming. A short distance further east the northeast-oriented South Fork Powder River enters and the Powder River flows east for another short distance before turning north and north-northeast in eastern Johnson County. Salt Creek originates just north of the word Pine Ridge near the Natrona County-Converse County line in the figure 2 south center and flows northwest through Edgerton to join the Powder River west of Sussex, Wyoming. The northeast-oriented Belle Fourche River originates near Pumpkin Buttes in southwest Campbell County and flows to the figure 2 north edge. The northeast-oriented Dry Fork Cheyenne River originates near the Natrona County-Converse County line at the figure 2 south edge and flows to the figure 2 east edge near the Converse County-Campbell County line. Antelope Creek originates near the common corner of the four counties and flows east just south of the Campbell County-Converse County line to join the Dry Fork Cheyenne River near the figure 2 east edge. Sand Creek is a northeast-oriented Antelope Creek tributary originating in western Converse County just east of the northwest-oriented Salt Creek headwaters (north of the word Pine Ridge). Detailed maps in this essay first illustrate the northeast end of the Powder River-Cheyenne River drainage divide area near Pumpkin Buttes in southwest Campbell County and then proceed southwest and south along the drainage divide. The essay ends with a look at the Salt Creek-Sand Creek drainage divide in the Pine Ridge area along the Natrona County-Converse County line.

Powder River-Cheyenne River drainage divide area near Pine Tree, Wyoming

Figure 3: Powder River-Cheyenne River drainage divide area near Pine Tree, Wyoming. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 3 illustrates the northeast end of the Powder River-Cheyenne River drainage divide area in the Pumpkin Buttes area. The South Prong of the Belle Fourche River originates near Pine Tree, Wyoming and then flows northeast (roughly parallel with the highway) to the figure 3 east edge. Northeast-oriented drainage east of the south-to-north oriented highway flows to the northeast-oriented Belle Fourche River. Southeast-oriented drainage southeast of the southwest-to-northeast oriented highway flows to Antelope Creek and then to the Cheyenne River. Northwest-oriented drainage west and north of Pine Tree flows to the Powder River. The northwest-southeast orientation of streams originating along the Powder River-Cheyenne River drainage divide is evidence the drainage divide was eroded by multiple southeast-oriented flood flow channels, such as might be found in a flood formed anastomosing channel complex. Southeast-oriented tributary valleys eroded northwest from what must have been a newly eroded deep Antelope Creek valley eroded west from what was then the actively eroding Cheyenne River valley to capture southeast-oriented flood flow and to divert flood waters around the Black Hills south end and then northeast into South Dakota and beyond. Headward erosion of the northeast-oriented Belle Fourche River-South Prong Belle Fourche River valley next beheaded southeast-oriented flood flow to what were then actively eroding southeast-oriented Antelope Creek tributary valleys east of Pine Tree. Next headward erosion of the deep north-oriented Powder River valley northwest of the figure 3 map area beheaded southeast-oriented flood flow to the actively eroding South Prong Belle Fourche River valley and then to the actively eroding southeast-oriented Antelope Creek tributary valleys west of Pine Tree. Flood waters on the northwest ends of the beheaded southeast-oriented flood flow channels reversed flow direction to flow northwest to the newly eroded and deeper north-oriented Powder River valley. This reversed flow captured yet to be beheaded southeast-oriented flood waters from flood flow channels south of the actively eroding Powder River valley head. With the aid of this captured flood water the reversed flow was frequently able to erode significant northwest-oriented Powder River tributary valleys.

Powder River-Cheyenne River drainage divide area near Artesian Draw

Figure 4: Powder River-Cheyenne River drainage divide area near Artesian Draw. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 4 illustrates the Powder River-Cheyenne River drainage divide area southwest of the figure 3 map area and includes overlap areas with figure 3. Northwest-oriented drainage flows to the north-oriented Powder River. Southeast-oriented Ninemile Creek flows to Antelope Creek (southeast of the figure 4 map area). Southeast-oriented Red Rock Draw flows to east-oriented Wind Creek (south of figure 4 map area), which flows to Antelope Creek and then to the Cheyenne River. Northwest-oriented Dry Fork flows to the north-oriented Powder River. Note how the Dry Fork headwaters flow roughly along the Johnson County-Campbell County line from the east side of the forested area in the figure 4 southwest corner. This will be important in understanding figure 6 below. Other figure 4 northwest-oriented drainage is tributary to northwest-oriented Dry Fork. The Powder River-Cheyenne River drainage divide in figure 4 is similar to the drainage divide seen in figure 3. Multiple southeast-oriented streams originate along the southeast side of the drainage divide while multiple northwest-oriented streams originate along the northwest side of the drainage divide. This evidence suggests the drainage divide was eroded by multiple southeast-oriented flood flow channels, such as might be found in a southeast-oriented anastomosing channel complex. The southeast-oriented valleys eroded headward from what must have been the newly eroded and east-oriented Antelope Creek-Wind Creek valley and headward erosion of the southeast-oriented valleys ceased when southeast-oriented flood flow channels were beheaded by the headward erosion of the deep Powder River valley to the northwest. Flood waters on the northwest ends of the beheaded flood flow channels reversed flow direction to erode northwest-oriented Powder River tributary valleys and also to create the Powder River-Cheyenne River drainage divide. Evidence presented here is not adequate to determine the flood water source, however based on evidence provided in numerous Missouri River drainage basin landform origins research project essays (published on this website) flood waters can be traced headward to a North American ice sheet location. Rapid melting of a thick North American ice sheet located in a deep “hole” would not only explain the flood water source, but would also explain why deep northeast-oriented valleys eroded headward into the Powder River Basin to capture south-oriented floods and to divert the flood water further and further northeast and north.

Detailed map of Artesian Draw-Red Rock Draw drainage divide

Figure 5: Detailed map of Artesian Draw-Red Rock Draw drainage divide. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 5 illustrates a detailed map of the Artesian Draw-Red Rock Draw drainage divide area seen in less detail in the figure 4 map area. Artesian Draw flows northwest to the figure 5 northwest corner and then to join northwest-oriented Dry Fork, which flows to the north-oriented Powder River. Southeast-oriented Red Rock Draw is located in the figure 5 south center and flows to east-oriented Wind Creek and then to Antelope Creek, which flows to the Cheyenne River. A close look at figure 5 reveals shallow through valleys linking northwest-oriented Artesian Draw headwaters with southeast-oriented Red Rock Draw headwaters. Similar through valleys can be seen at the head of east-oriented Ninenemile Creek further to the north. Ninemile Creek flows to east-oriented Antelope Creek and the Cheyenne River and unnamed drainage west of the Ninemile Creek headwaters flows to northwest-oriented Dry Fork and the Powder River. Such through valleys are commonplace along the Powder River-Cheyenne River drainage divide and are further evidence southeast-oriented flood water once flowed across the region. The valleys were eroded by water. The presence of multiple through valleys is evidence there were multiple flow routes active at approximately the same time. The best explanation for such a pattern of multiple flow routes is the southeast-oriented anastomosing channel complex that was beheaded by headward erosion of the deep Powder River valley to the northwest.

Powder River-Cheyenne River drainage divide area east of Edgerton, Wyoming

Figure 6: Powder River-Cheyenne River drainage divide area east of Edgerton, Wyoming. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 6 illustrates the Powder River-Cheyenne River drainage divide area southwest of the figure 4 map area and includes overlap areas with figure 4. The Powder River-Cheyenne River drainage divide has a different look in figure 6 from that seen in figures 3 and 4. The drainage divide appears to be a north-south oriented ridge opposed to the northeast-southwest orientation seen previously. However, north of east-oriented North Fork Wind Creek (figure 6 northeast quadrant) are headwaters of northwest-oriented Dry Fork, which was seen in figure 4 and which turns northwest to flow to the north-oriented Powder River. South of North Fork Wind Creek the Powder River-Cheyenne River drainage divide in figure 6 is a well-defined ridge and headwaters of some of the north-oriented Powder River tributaries are southwest-oriented. Starting in the north, where Natrona and Converse Counties meet Johnson County, north-south oriented Pine Ridge (Powder River-Cheyenne River drainage divide) separates east-oriented North Fork Wind Creek drainage (flowing to Antelope Creek and the Cheyenne River) from northwest-oriented Meadow Creek drainage (flowing to north-oriented Salt Creek and the north-oriented Powder River). Figure 7 below illustrates this Meadow Creek-North Fork Wind Creek drainage divide area in detail. Further south note north-northwest oriented Salt Creek flowing from the figure 6 south edge to the figure 6 west edge near Edgerton, Wyoming. Salt Creek is a major Powder River tributary (see figures 1 and 2) and was formed by a reversal of flood flow on what must have been a major southeast-oriented flood flow route (figures 8, 9, and 10 illustrate where the southeast-oriented Salt Creek valley flood flow was going). Southwest-oriented Salt Creek tributary valleys were eroded by headward erosion of southwest-oriented valleys into the wall of the southeast-oriented Salt Creek valley, prior to reversal of Salt Creek flood flow. That southeast-oriented Salt Creek valley was being eroded to the north so southwest-oriented tributary valleys formed from south to north, which enabled each new southwest-oriented valley to behead southeast-oriented flood flow to the previously formed valley south of it. Headward erosion of the deep north-oriented Powder River valley then beheaded southeast-oriented Salt Creek flood flow, causing a reversal of flood flow, which turned the southeast-oriented Salt Creek valley into a north-oriented Salt Creek valley.

Detailed map of Meadow Creek-Wind Creek drainage divide

Figure 7: Detailed map of Meadow Creek-Wind Creek drainage divide. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 7 illustrates a detailed map of the Meadow Creek-North Fork Wind Creek drainage divide seen in less detail in the figure 6 map area. The Powder River-Cheyenne River drainage divide north of the North Fork Wind Creek (flowing to the figure 7 east edge center) is not the well-defined north-south oriented Pine Ridge. In the figure 7 northeast corner are the northeast-oriented North and South Prongs of north and northwest-oriented Dry Fork (seen in figures 4 and 6), which flows to the north oriented Powder River. A close look at the area between the northeast-oriented South Prong Dry Fork and east-oriented North Fork Wind Creek reveals through valleys linking what are today the Powder River and Cheyenne River drainage basins. These through valleys are evidence of a complicated erosion history where headward erosion of the northeast-oriented South Prong valley (from a north and northwest-oriented valley) was being caused by reversed flood flow moving to the newly eroded north-oriented Powder River valley. That reversed flood flow captured yet to be beheaded southeast-oriented flood flow. For example, Meadow Creek flows northwest from the figure 7 central area to the figure 7 northwest quadrant and north edge and then on to join north-oriented Salt Creek and the north-oriented Powder River. Southeast-oriented flood flow on the Meadow Creek alignment probably was not yet beheaded when the northeast-oriented South Prong valley eroded into the region and it was southeast-oriented flood flow on the Meadow Creek alignment that eroded the northeast-oriented South Prong valley and north- and northwest-oriented Dry Fork valley (as well as the east-oriented North Fork Wind Creek valley headward from the Antelope Creek and Cheyenne River valleys to the east). Even though the drainage divide in figure 7 south of Meadow Creek and North Fork Wind Creek is the well-defined Pine Ridge, a close look reveals shallow through valleys eroded across it. Those shallow through valleys are evidence multiple flow routes once crossed the Pine Ridge area, probably carrying flood water from the west to the east. Why the ridge was not eroded deeper is hard to tell from topographic map evidence alone, although probably the underlying bedrock resistance to erosion played a significant role.

Powder River-Cheyenne River drainage divide area east of Teapot Dome

Figure 8: Powder River-Cheyenne River drainage divide area east of Teapot Dome. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 8 illustrates the Powder River-Cheyenne River drainage divide area south of the figure 6 map area and includes overlap areas with figure 6. Salt Creek flows northwest from the figure 8 south edge center to the figure 8 northwest corner. Little Teapot Creek flows north and north-northwest from the Teapot Dome area along the figure 8 west edge and joins Salt Creek west of the figure 8 map area. Salt Creek as previously described flows north to join the north-oriented Powder River. Antelope Creek headwaters flow east from the Pine Ridge area (figure 8 center) and then northeast to the figure 8 northeast quadrant. North Sand Creek flows east from Pine Ridge to the figure 8 east center edge. South of North Sand Creek are several east-northeast oriented tributaries to northeast-oriented Sand Creek, which can just barely be seen in the figure 8 southeast corner. As previously mentioned Sand Creek is an Antelope Creek tributary and Antelope Creek flows east to join the southeast-oriented Cheyenne River, which after flowing around the Black Hills south end turns northeast. The Powder River-Cheyenne River drainage divide in this figure 8 map area is the well-defined Pine Ridge. Both sides of the divide have been deeply eroded. As previously mentioned what is today the north-northwest oriented Salt Creek valley was initially eroded as south-southeast oriented valley. Initially southeast-oriented flood water flowed on a topographic surface at least as high as Pine Ridge today and was systematically captured by headward erosion of northeast-oriented Antelope Creek tributary valleys from what was then an actively eroding and deep Antelope Creek (eroding west from the deep Cheyenne River valley). Headward erosion of these northeast-oriented oriented tributary valleys was responsible for deep erosion of the area east of Pine Ridge. The south-southeast oriented Salt Creek valley west of Pine Ridge was eroded deeper because south of the figure 8 map area there is a deep valley cut across Pine Ridge, which enabled flood flow to directly flow into the deep northeast-oriented Sand Creek valley. Reversed flood flow after southeast-oriented flood flow on the south-oriented Salt Creek route after headward erosion of the deep Powder River valley beheaded the Salt Creek flow route, further eroded the area west of Pine Ridge.

Salt Creek-Sand Creek drainage divide

Figure 9: Salt Creek-Sand Creek drainage divide. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 9 illustrates the Powder River-Cheyenne River drainage divide area south of the figure 8 map area and includes overlap areas with figure 8. Salt Creek originates in the figure 9 south center as a northeast-oriented stream, which quickly turns northwest to flow to the figure 9 west edge (center north) and then to the north-oriented Powder River. Northeast-oriented Sand Creek originates a short distance east of the Salt Creek headwaters and flows northeast and north to the figure 9 northeast quadrant and north edge and then to join Antelope Creek, which flows to the Cheyenne River. Multiple through valleys carved across Pine Ridge in the figure 9 map area are evidence large volumes of water flowed southeast into the region and then were captured by headward erosion of deep northeast-oriented Sand Creek tributary valleys, which diverted the flood waters to the Cheyenne River valley. Apparently, as flood waters eroded the region Pine Ridge became a barrier flood waters had to flow around and this location was one place where flood waters were able to do so. Headward erosion of the deep north-oriented Powder River beheaded southeast-oriented flood flow to the figure 9 map area, causing a reversal of flood flow on the northwest end of the beheaded Salt Creek flood flow route. Northeast-oriented Salt Creek tributaries along the figure 9 west edge suggest reversed flood flow on the Salt Creek flood flow route captured significant yet to be beheaded (by Powder River valley headward erosion) southeast-oriented flood flow further to the south. Such captured flood waters helped erode the northwest-oriented Salt Creek valley. The reversal of flood flow also was responsible for creating what is today the Powder River-Cheyenne River (Salt Creek-Sand Creek) drainage divide.

Detailed map of Salt Creek-Sand Creek drainage divide

Figure 10: Detailed map of Salt Creek-Sand Creek drainage divide. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 10 illustrates a detailed map of the Salt Creek-Sand Creek drainage divide area seen in less detail in the figure 9 map area. Sand Creek flows northeast to the figure 10 east edge center. Salt Creek flows north from the figure 10 south center and then turns northwest to flow the figure 10 west edge (center north). Multiple through valleys link Sand Creek and northeast-oriented Sand Creek tributaries with the north and northwest-oriented Salt Creek valley. The through valleys are evidence water once flowed southeast along the Salt Creek and flowed in multiple channels across what is now the Salt Creek-Sand Creek drainage divide. The water flowing along that route was flowing from what is now the Powder River drainage basin into what is now the Cheyenne River drainage basin. The fact there were multiple channels is strong evidence of flood flow and of an anastomosing channel complex. What has happened here is headward erosion of the deep Cheyenne River valley around the Black Hills south end and northwest into the Powder River Basin area captured southeast-oriented flood flow and diverted it northeast, east and southeast around the Black Hills south end and then northeast into South Dakota and perhaps somewhere further beyond. Subsequently headward erosion of the deep north-oriented Powder River valley into the Powder River Basin area beheaded the southeast-oriented flood flow to what was then the newly eroded Cheyenne River valley and diverted the flood waters further to the north and northeast. Evidence along the Powder River-Cheyenne River drainage divide supports the “thick ice sheet located in a deep ‘hole’ and that melted fast” paradigm.

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.