A geomorphic history based on topographic map evidence

The Yellowstone River-Tongue River drainage divide area is located in eastern Montana, USA. Although detailed topographic maps of the Yellowstone River-Tongue 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 Yellowstone River-Tongue 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. Flood erosion across the drainage divide ended when headward erosion of the deep east and northeast-oriented Yellowstone River valley captured all southeast-oriented flood flow.

Introduction:

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

Yellowstone River-Tongue River drainage divide area location map

Figure 1: Yellowstone River-Tongue 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 Yellowstone River-Tongue River drainage divide area location map and illustrates a region in eastern Montana. The Yellowstone River flows from Billings in a northeast direction to Glendive, located on the figure 1 east edge. The Missouri River flows east from the figure 1 west edge to Fort Peck Lake, which is a reservoir flooding the Missouri River valley. The Tongue River flows northeast and northwest from the figure 1 south edge to join the Yellowstone River at Miles City. Figure 1 illustrates southeast and northwest-oriented Yellowstone River tributaries. The southeast and northwest-orientation of tributary valleys is evidence the northeast-oriented Yellowstone River valley eroded southwest across multiple southeast-oriented flood flow routes, such as might be found in a large-scale flood-formed anastomosing channel complex. Northwest-oriented tributary valleys were eroded by reversed flood flow on northwest ends of beheaded flood flow channels. Because channels were anastomosing (meaning they were interconnected) reversed flood flow on beheaded flood flow channels often captured yet to be beheaded southeast-oriented flood flow from flood flow channels further to the southwest. Such captures of yet to be beheaded flood flow often helped erode significant northwest-oriented tributary valleys. The northeast-oriented Tongue River valley upstream from the northwest-oriented Tongue River valley near Miles City, was eroded by such yet to be beheaded southeast-oriented flood flow. Based on the northwest-southeast orientation of tributary streams, landform evidence illustrated in this essay is interpreted in the context of an immense southeast-oriented flood flowing across the entire figure 1 map area and which was systematically captured and diverted further and further to the northeast by headward erosion of deep valleys eroded into a topographic surface at least as high as the figure 1 region highest elevations today. In the figure 1 map region headward erosion of the northeast-oriented Tongue River valley first captured the southeast-oriented flood flow and then headward erosion of the Yellowstone River valley captured the same southeast-oriented flood flow routes and diverted the flood waters more directly to the northeast-oriented Yellowstone River valley (downstream from Miles City, Montana). Detailed maps below provide evidence supporting this interpretation. The Big Dry Creek-Yellowstone River drainage divide area essay and the Musselshell River-Yellowstone River drainage divide area essay describe regions located northwest and north of the Yellowstone River-Tongue River drainage divide area discussed here and can be found under Yellowstone River on the sidebar category list. The Pumpkin Creek-Mizpah Creek drainage divide area essay and in the Mizpah Creek-Powder River drainage divide area essay describe regions located east and southeast of the area discussed here and can be found under Powder River on the sidebar category list.

Yellowstone River-Tongue River drainage divide area detailed location map

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

Figure 2 illustrates a somewhat more detailed map of the Yellowstone River-Tongue River drainage divide area discussed here. Treasure, Rosebud, and Custer Counties are located in Montana. The Yellowstone River-Tongue River drainage divide area discussed here is located primarily in western Custer County and eastern Rosebud County. The Yellowstone River flows east and northeast through Forsyth and Miles City to the figure 2 east edge. The north-oriented Tongue River is located at the figure 2 south edge center and then turns to flow northeast before turning northwest to flow to the northeast-oriented Yellowstone River at Miles City. Figure 2 shows numerous southeast-oriented Yellowstone River and Tongue River tributaries. Also, many Yellowstone River and Tongue River tributaries from the east and south are northwest-oriented. This northwest-southeast drainage alignment is evidence the northeast-oriented Tongue River valley eroded southwest and south across an immense southeast-oriented flood to capture flood waters and to divert flood waters northeast. Further, the drainage alignment is evidence the east and northeast-oriented Yellowstone River valley subsequently eroded southwest and west to capture the same southeast-oriented flood flow. The southeast-oriented tributary valleys were eroded by southeast-oriented flood flow moving into the newly eroded and deep Tongue River and Yellowstone River valleys. The northwest-oriented tributary valleys were eroded by reversed flood flow on the northwest ends of beheaded southeast-oriented flood flow routes. Because flood waters move in and erode anastomosing (or interconnected) channels reversed flood flow on a beheaded flood flow route could capture flood flow from yet to be beheaded flood flow routes. Such captures of yet to be beheaded flood flow could enable the reversed flood flow routes to erode much deeper and larger northwest-oriented valleys than might otherwise be possible. Often evidence for such flow reversals and captures can be found on detailed topographic maps. Detailed maps below illustrate the Moon Creek-Tongue River drainage divide, Graveyard Creek-Tongue River drainage divide, Sweeney Creek-Tongue River drainage divide, and Rosebud Creek-Tongue River drainage divide, among to illustrate how southeast-oriented flood waters were reversed and then captured yet to be beheaded flood flow that helped erode northwest-oriented valleys.

Yellowstone River-Tongue River drainage divide area southwest of Miles City

Figure 3: Yellowstone River-Tongue River drainage divide area southwest of Miles City. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 3 illustrates the Yellowstone River-Tongue River drainage divide area immediately southwest of Miles City, Montana. The Yellowstone River is the large river flowing northeast through Miles City. The Tongue River is the large river flowing northwest to join the northeast-oriented Yellowstone River at Miles City. Note how all Yellowstone River tributaries from the south are northwest-oriented. The northwest-oriented Tongue River has northeast-oriented tributaries, the most significant of which is Paddy Fay Creek. However, note how Paddy Fay Creek has southeast-oriented tributaries and how those southeast-oriented Paddy Fay Creek tributaries are linked to northwest-oriented Yellowstone River tributaries. The northwest-southeast orientation of the Yellowstone River and Paddy Fay Creek valleys is evidence the Paddy Fay Creek valley and subsequently the Yellowstone River valley eroded southwest to capture multiple southeast-oriented flood flow routes. The flood flow routes were probably along anastomosing (or interconnected) channels in a large southeast-oriented anastomosing channel complex. Headward erosion of a deep northeast-oriented valley across such southeast-oriented channels would capture the southeast-oriented flood flow and divert the flood waters to the northeast. Also, flood waters on the northwest ends of the beheaded flood flow channels would reverse flow direction to flow northwest into the newly eroded and deeper northeast-oriented valley. Reversed flood flow on such beheaded southeast-oriented flood flow channels often captured yet to be beheaded flood flow from channels further to the southwest. The Paddy Fay Creek valley was probably eroded by such captured flood water moving northeast to the newly reversed northwest-oriented Tongue River valley alignment, which had been reversed by headward erosion of the deep northeast-oriented Yellowstone River. At the time the Paddy Fay Creek was eroded the deep Yellowstone River valley headcut was still eroding southwest from Miles City and flood waters could still flow freely across what is today the deep Yellowstone River valley.

Moon Creek-Tongue River drainage divide area

Figure 4: Moon Creek-Tongue River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 4 illustrates the Moon Creek-Tongue River drainage divide area southwest of the figure 3 map area and includes overlap areas with figure 3. The northeast oriented Tongue River is located in the figure 4 southeast corner. East of figure 4 the Tongue River turns to flow northwest to the Yellowstone River as seen in figure 3. The northeast oriented Tongue River valley eroded southwest to capture yet to be beheaded flood flow routes still moving southwest of the active and deep northeast oriented Yellowstone River valley headcut, which was eroding the deep Yellowstone River valley north of the figure 4 map area. Note how figure 4 Tongue River tributaries are southeast-oriented. These southeast-oriented Tongue River tributaries are evidence the deep northeast oriented Tongue River valley eroded headward across southeast-oriented flood flow. Note also northwest-oriented Yellowstone River tributaries, especially in the figure 4 northwest quadrant. Moon Creek is a northeast, north, and northwest-oriented Yellowstone River tributary with southeast-oriented tributaries to the northeast- and north oriented valley segments. The southeast-oriented Moon Creek tributaries provide evidence the northwest-oriented Moon Creek valley was eroded by reversed flood flow on the northwest end of a beheaded southeast-oriented flood flow channel. The north and northeast-oriented Moon Creek valley segments were eroded by flood waters from yet to be beheaded flood flow channels captured by reversed flow on the newly beheaded Moon Creek alignment. The southeast-oriented Moon Creek tributary valleys were also eroded by those yet to be beheaded southeast-oriented flood flow channels. As headward erosion of the deep Yellowstone River valley progressed further to the southwest flood flow on the Cottonwood Creek alignment was next reversed to erode the present day northwest-oriented Cottonwood Creek valley. And the reversal of southeast-oriented flood flow channels continued in sequence as the deep Yellowstone River valley continued to erode to the southwest and then west.

Graveyard Creek-Tongue River drainage divide area

Figure 5 illustrates the Graveyard Creek-Tongue River drainage divide area southwest of the figure 4 map area and includes overlap areas with figure 4. The northeast-oriented Tongue River is located in the figure 5 southeast corner. Northeast-oriented Moon Creek headwaters are located in the figure 5 northeast quadrant. Graveyard Creek originates in the figure 5 west center and flows northeast before turning to flow northwest in the figure 5 northwest quadrant. Note how tributaries to the northeast-oriented Tongue River valley are southeast-oriented. These southeast-oriented tributaries provide evidence the Tongue River valley eroded southwest to capture multiple southeast-oriented flood flow channels, such as might be found in a southeast-oriented anastomosing channel complex. Some northwest-oriented Tongue River tributaries can be seen in the figure 5 southeast corner. The northwest-oriented tributary valleys were eroded by reversals of flood flow on the northwest ends of beheaded flood flow channels. North of the Yellowstone River-Tongue River drainage divide are the northeast-oriented Moon Creek and Graveyard Creek drainage routes. Moon Creek as seen in figure 4 above turns to flow in a northwest direction to the northeast-oriented Yellowstone River. Graveyard Creek, as seen here and in figure 8 below turns northwest and then north to flow to the Yellowstone River. Like reversed flood flow on the northwest-oriented Moon Creek valley segment, reversed flood flow on what is today the northwest-oriented Graveyard Creek valley segment captured yet to be beheaded southeast-oriented flood flow from flood flow channels further to the southwest (i.e. flood flow moving to erode the southeast-oriented Sixmile Creek valley headward from the northeast-oriented Tongue River valley). Captured flood waters moved northeast to the newly reversed northwest-oriented Graveyard Creek valley alignment and in the process eroded what is today the northeast-oriented Graveyard Creek headwaters valley segment. Subsequently, headward erosion of the deep Yellowstone River valley beheaded and reversed flood flow on the northwest end of the flood flow route that had been eroding the southeast-oriented Sixmile Creek valley and supplying water to erode the northeast-oriented Graveyard Creek valley.

Sweeney Creek-Tongue River drainage divide area

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

Figure 6 illustrates the Sweeney Creek-Tongue River drainage divide southwest of the figure 5 map area and includes overlap areas with figure 5. The northeast oriented Tongue River is located in the figure 6 southeast corner. Northeast-oriented Hay Creek located in the figure 6 northeast corner flows to northeast and northwest oriented Moon Creek. Northeast-oriented headwaters of Graveyard Creek are located along the figure 6 north edge (center east). West of the northeast-oriented Graveyard Creek headwaters are headwaters of northwest-oriented Hay Creek, which are linked to headwaters of southeast-oriented Sixmile Creek, which flows to the northeast-oriented Tongue River. North of figure 6 northwest-oriented Hay Creek flows to northwest-oriented Sweeney Creek, which is located in figure 6 west of Hay Creek. Sweeney Creek headwaters are northeast-oriented, suggesting reversed flood flow on the Sweeney Creek alignment captured flood waters from yet to be beheaded flood flow routes further to the southwest and the captured flood waters flowed northeast to the newly beheaded and reversed flood flow on the Sweeney Creek alignment. Subsequently the yet to be beheaded flood flow was captured in sequence by what are today additional northeast-oriented Sweeney Creek tributary valleys. The first of these northeast-oriented valleys to erode southwest to capture southeast-oriented flood flow to the northeast-oriented Sweeney Creek headwaters was Beaver Creek. Note the northwest-oriented Beaver Creek headwaters, which provide evidence headward erosion of the northeast-oriented Beaver Creek valley beheaded and reversed a southeast-oriented flood flow route. Subsequently the northeast-oriented Bell Creek valley, the northeast-oriented Twelvemile Creek valley, and an unnamed northeast-oriented valley eroded southwest to capture the southeast-oriented flood flow and diverted the flood waters to the newly beheaded and newly reversed Sweeney Creek alignment. Figure 9 below illustrates how flood waters were subsequently captured by headward erosion of north-oriented Rosebud Creek and its northwest, southwest, and west-oriented East Cottonwood Creek tributary valley.

Rosebud Creek-Tongue River drainage divide area

Figure 7 illustrates the Rosebud Creek-Tongue River drainage divide area southwest of the figure 6 map area and includes overlap areas with figure 6. The northeast-oriented Tongue River is located in the figure 7 southeast corner. North-northwest-oriented Rosebud Creek is located in the figure 7 southwest corner. Tongue River tributaries from the north are southeast-oriented and provide evidence the deep northeast-oriented Tongue River valley eroded southwest to capture multiple southeast-oriented flood flow routes, such as would be expected in a southeast-oriented anastomosing channel complex. Tributaries to north-northwest and north oriented Rosebud Creek are less consistent in orientation, although some tributaries provide evidence of reversed flood flow on beheaded southeast-oriented flood flow routes. Eagle Creek in the figure 7 northwest quadrant begins as a northwest-oriented stream and then flows west to Rosebud Creek. The northwest-oriented Eagle Creek headwaters valley was eroded by reversed flood flow on a beheaded southeast-oriented flood flow route. Northwest-oriented Eagle Creek headwaters are also linked by through valleys with southeast-oriented Ranch Creek, which flows to the northeast-oriented Tongue River (see figure 10 below). The through valleys are evidence that prior to reversal of flood flow in the Eagle Creek valley southeast-oriented flood flow moved from the present day Eagle Creek drainage basin to erode the Ranch Creek valley. South of Eagle Creek is Goodman Creek, which also has a northwest-oriented valley segment. That northwest-oriented Goodman Creek valley segment is also evidence of reversed flow on what was at one time a southeast-oriented flood flow route. South of Goodman Creek is west-northwest oriented Cherry Creek. The west-northwest Cherry Creek orientation is evidence of reversed flow on a southeast-oriented flood flow route, although it is also evidence flood waters may have moved in an easterly direction toward what was probably the deep and actively eroding northeast-oriented Tongue River valley headcut. Depth of the deep Tongue River valley headcut was probably drawing in flood waters from the west, which then may have influenced the orientation of Rosebud Creek, which eroded south across the more easterly oriented flood flow. South of the figure 7 map area the Rosebud Creek and Tongue River valleys come close together before they diverge, with the Rosebud Creek valley turning to the southwest while the Tongue River valley turns to the south.

Yellowstone River valley north of Graveyard Creek-Tongue River drainage divide

Figure 8 illustrates the Yellowstone River valley west and south of the figure 4 map area and includes overlap areas with figure 4 and 5. Note how Yellowstone River tributaries are northwest-oriented or have northwest-oriented segments. The northwest-orientation of these tributary valleys is evidence the deep northeast-oriented Yellowstone River eroded southwest across multiple southeast-oriented flood flow routes such as might be found in a southeast-oriented anastomosing channel complex. The northwest-oriented tributary valleys were eroded by reversed flood flow on the northwest ends of beheaded southeast-oriented flood flow routes. As described previously reversed flood flow often captured yet to be beheaded southeast-oriented flood flow from flood flow routes further to the southwest. Such captured flood flow helped the reversed flood flow erode significant northwest-oriented valleys. The depth and size of the Yellowstone River valley provides some local clues as to the magnitude of the flood involved and also as to the amount of erosion accomplished. However, the local clues must be combined with evidence from the throughout the northern plains region and the northern Rocky Mountain region to fully understand the volume of flood water involved and the amount of erosion accomplished. The source of the flood waters cannot be determined from evidence provided here, although as a group the Missouri River drainage basin landform origins research project essays published on this website can be used to trace flood waters headward toward their source. Headward in this case is north and west, which suggests a logical flood water source might be rapid melting of a thick North American ice sheet located in a deep “hole”. The deep North American “hole” would have been created by deep glacial erosion and the ice sheet weight. Such a flood water source would not only explain the immense quantities of water involved, but would also explain why deep northeast-oriented valleys were eroding headward to capture immense southeast-oriented floods and divert south-oriented flood waters northeast into space the rapidly melting ice sheet had once occupied.

East Cottonwood Creek-Sweeney Creek drainage divide

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

Figure 9 illustrates the Rosebud Creek-Sweeney Creek drainage divide area north of the figure 7 map area and includes overlap areas with figure 7. Rosebud Creek flows north-northwest and northwest across the figure 9 west half. Northwest-oriented Sweeney Creek is located in the figure 9 northeast quadrant. Headwaters of southeast-oriented Tongue River tributaries are located in the figure 9 southeast corner. Rosebud Creek in the figure 9 southwest quadrant are east-oriented from the west and west-oriented from the east, although east-oriented Goodman Creek and Eagle Creek have northwest-oriented headwaters. Figure 10 below illustrates the Eagle Creek-Ranch Creek drainage divide area in detail. East Cottonwood Creek is an interesting Rosebud Creek tributary from the east. East Cottonwood Creek begins as a northwest-oriented stream, indicating that valley segment was eroded by reversed flood flow on a beheaded southeast-oriented flood flow route. However, after flowing northwest East Cottonwood Creek turns southwest and then west to flow to northwest-oriented Rosebud Creek. East Cottonwood Creek headwaters are linked with headwaters of northeast-oriented Sweeney Creek tributaries and also with headwaters of south-oriented Eagle Creek tributaries. It appears possible that for a time  prior to being captured by headward erosion of the northeast-oriented Sweeney Creek tributary valleys southeast-oriented flood waters on the Rosebud Creek alignment were flowing east on the East Cottonwood Creek and Eagle Creek alignments and then southeast to the Tongue River valley. Subsequently reversed flood flow on the Sweeney Creek alignment captured the east-oriented flood flow from the Rosebud Creek alignment and diverted the flood water northeast and then northwest to the newly eroded and deep Yellowstone River valley. This interpretation is only one of several possible interpretations and there may be other better interpretations for this set of evidence.

Detailed map of Eagle Creek-Ranch Creek drainage divide

Figure 10 illustrates a detailed map of the northwest-oriented Eagle Creek headwaters area and multiple through valleys linking the Eagle Creek drainage basin with southeast-oriented Ranch Creek seen in less detail in figures 7 and 9 above. Ranch Creek flows southeast to the figure 10 southeast corner. Eagle Creek flows northwest to the figure 10 northwest corner. Note how there are multiple through valleys eroded across the present day Eagle Creek-Ranch Creek drainage divide. Those through valleys provide evidence southeast-oriented flood waters once flowed from the present day Eagle Creek drainage basin to the present day Ranch Creek drainage basin and then to the northeast-oriented Tongue River valley. Flood flow across the Eagle Creek-Ranch Creek drainage divide ended when southeast-oriented flow was beheaded somewhere to the northwest of the figure 10 map area, probably by headward erosion of the deep northeast-oriented Yellowstone River valley. Flood waters in the Eagle Creek drainage basin then reversed flow direction and to flowed northwest to the north and northwest-oriented Rosebud Creek valley and then to the northeast-oriented Yellowstone River valley. The reversal of flood flow in the Eagle Creek drainage basin created the present day Eagle Creek-Ranch Creek drainage divide, which is also the Rosebud Creek-Tongue River drainage divide.

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.