A geomorphic history based on topographic map evidence

The Mizpah Creek-Powder River drainage divide area discussed here is located in southeastern Montana, USA. Although detailed topographic maps of the Mizpah Creek-Powder 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 Mizpah Creek-Powder 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 ended when headward erosion of the north and northwest-oriented Pumpkin Creek valley captured all southeast-oriented flood flow.

Introduction:

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

Mizpah Creek-Powder River drainage divide area general location map

Figure 1: Mizpah Creek-Powder 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.

The Powder River begins in central Wyoming and flows northeast into Montana, past Broadus and Powderville (see figure 1 south center) and then turns north-northwest to flow to the northeast-oriented Yellowstone River. Mizpah Creek begins southwest of Broadus, Montana and flows north to join the north-northwest-oriented Powder River. West of the Mizpah Creek drainage basin is the north-northeast and northwest-oriented Pumpkin Creek drainage basin, with Pumpkin Creek flowing to a northwest-oriented Tongue River segment, which flows to the northeast-oriented Yellowstone River. East of the north-northwest-oriented Powder River segment is the northwest-oriented O’Fallon Creek drainage basin. Another essay addresses landform evidence along the Powder River-O’Fallon Creek drainage divide and can be found under Powder River on the sidebar category list. East of the northeast-oriented Powder River segment is the northeast-oriented Boxelder Creek drainage basin. Boxelder Creek flows to the north- and northeast-oriented Little Missouri River and a different essay addresses landform evidence along the Powder River-Boxelder Creek drainage divide and is also found under Powder River (and also Little Missouri River) on the sidebar category list. Evidence illustrated in this essay is interpreted in the context of an initial immense southeast-oriented flood that originally flowed across the entire region on a topographic surface at least as high as the highest points located in the present day Mizpah Creek-Powder River drainage divide area. Southeast-oriented flood waters were systematically captured first by headward erosion of the northeast-oriented Boxelder Creek valley, which diverted the flood waters northeast and north into western North Dakota and probably beyond; second by headward erosion of the northeast-oriented Powder River valley segment, which diverted the flood waters northeast and north-northwest to the northeast-oriented Yellowstone River valley and probably to somewhere in Canada; third by headward erosion of the north-oriented Mizpah Creek valley, which diverted the flood waters north and then north-northwest along the Powder River to the northeast-oriented Yellowstone River valley; and fourth by headward erosion of the northeast-oriented Yellowstone River valley, which beheaded southeast-oriented flood flow to the Mizpah Creek valley, causing a reversal of flood flow that eroded northwest-oriented Tongue River-Pumpkin Creek valley segments and then eroded the north-northeast-oriented Pumpkin Creek valley south-southwest to further capture southeast-oriented flood water that was moving to the newly eroded north-oriented Mizpah Creek valley.

Mizpah Creek-Powder River drainage divide area detailed location map

Figure 2: Mizpah Creek-Powder 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 Mizpah Creek-Powder River drainage divide area this essay discusses. The Powder River flows northeast and then north-northwest across the figure 2 center. Mizpah Creek flows north from near the northeast-oriented Powder River near Broadus, Montana (figure 2 south center) to join the north-northwest-oriented Powder River near Mizpah, Montana. Powder River tributaries from the east are nearly all northwest-oriented. Figure 2 does not show many Powder River tributaries flowing from the Mizpah Creek-Powder River drainage divide area to the Powder River. One notable exception is north-northwest-oriented Ash Creek. Detailed topographic maps illustrated below will show orientations of Powder River tributaries from the west. Nearly all Mizpah Creek tributaries flowing from the Mizpah Creek-Powder River drainage divide area shown in figure 2 flow in a northwest direction. Many Mizpah Creek tributaries from the west are southeast-oriented, especially in the southern half of the Mizpah Creek drainage basin. Pumpkin Creek tributaries flowing from the Pumpkin Creek-Mizpah Creek drainage divide are northwest-oriented. The predominance of northwest-southeast oriented tributaries to major north-oriented trunk streams shown in figure 2 is evidence supporting the previously described southeast-oriented flood interpretation and an interpretation the north-oriented trunk stream valleys eroded headward across multiple southeast-oriented flood flow routes. The multiple southeast-oriented flow routes suggests an immense ever-changing complex of anastomosing channels being carved into the regional landscape as flood waters stripped an initial high level topographic surface to produce the topographic surface that exists today. Headward erosion of the north-oriented trunk stream valleys proceeded from east to west, which would be logical if the north- and northeast-oriented Little Missouri River-Boxelder Creek valley headward erosion first captured the southeast-oriented flood flow, Powder River valley headward erosion next captured the southeast-oriented flood flow, Mizpah Creek valley headward erosion next captured the southeast-oriented flood low, and finally headward erosion of the Pumpkin Creek valley next captured the southeast-oriented flood flow.

Mizpah Creek-Powder River drainage divide south of Mizpah Creek-Powder River confluence

Figure 3: Mizpah Creek-Powder River drainage divide south of Mizpah Creek-Powder River confluence. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 3 illustrates the Mizpah Creek-Powder River confluence and the Mizpah Creek-Powder River drainage divide area immediately south of the confluence area. The Powder River here is flowing in a northwest direction. The northwest-orientation resulted from a reversal of southeast oriented flood flow on a flood flow route to what was at the time of the reversal an actively eroding northeast-oriented Little Missouri River-Beaver Creek valley head further to the southeast. The flood flow reversal occurred when the deep Yellowstone River valley eroded headward (or southwest) and beheaded the southeast oriented flood flow route and because the newly eroded northeast-oriented Yellowstone River valley was much deeper than the actively eroding Little Beaver Creek valley. Flood waters on the northwest end of the beheaded flood flow route reversed flow direction to flow northwest and to erode a deep northwest-oriented valley headward along the former southeast oriented flood flow route alignment. Southwest-oriented Powder River tributaries from the east have southeast and northwest-oriented tributaries indicating they eroded headward to capture either the initial southeast oriented flood flow or flood flow on reversed northwest-oriented flood flow routes. In either case flood flow on the beheaded ends of the captured flood flow routes would have reversed flow direction to flow back to the newly eroded southwest-oriented tributary valleys. For example southwest-oriented Devils Hole Creek has southeast and northwest-oriented tributaries, which indicate the Devils Hole Creek valley eroded headward to capture southeast- or northwest-oriented flood flow. Northeast-oriented Powder River tributaries from the west were probably eroded after the flow reversal took place and diverted southeast-oriented flood flow to the newly reversed and newly eroded northwest-oriented Powder River valley. Mizpah Creek tributaries from the east (from the Mizpah Creek-Powder River drainage divide area) are almost all northwest-oriented and reflect reversals of flow on beheaded southeast-oriented flood flow routes. Southeast-oriented Mizpah Creek tributary valleys from the west and southeast-oriented tributary valleys to east-oriented Mizpah Creek tributary valleys from the west probably were eroded along southeast-oriented flood flow routes captured by headward erosion of the north-oriented Mizpah Creek valley or of its east-oriented tributary valleys.

Mizpah Creek-Ash Creek drainage divide area north

Figure 4: Mizpah Creek-Ash Creek drainage divide area north. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 4 illustrates the Mizpah Creek-Powder River drainage divide region south of the figure 3 map area and provides an overlap strip. The Mizpah Creek-Powder River drainage divide area here is complicated by the north-oriented Ash Creek drainage basin located between the north-oriented Mizpah Creek drainage basin and the northwest-oriented Powder River valley. Like the north-oriented Mizpah Creek valley to the west the north-oriented Ash Creek valley eroded south to capture southeast-oriented flood flow moving to what was then newly reversed northwest-oriented flood flow on the northwest-oriented Powder River valley alignment. The north-oriented Ash Creek valley eroded south prior to north-oriented Mizpah Creek valley headward erosion, although there is evidence the two valleys eroded south at about the same time and the Mizpah Creek valley was eroding south faster than the Ash Creek valley. North of northeast-oriented Monarch Creek most Ash Creek tributaries are east-oriented and some even have southeast-oriented tributaries indicating Ash Creek was capturing flood water routes yet to be beheaded by Mizpah Creek valley headward erosion. However, the northeast-oriented Monarch Creek valley suggests the actively eroding Ash Creek valley head was at that point no longer capturing southeast-oriented flood flow routes, but was capturing flood waters moving on flood flow routes from south of the actively eroding Ash Creek valley head. Figure 5 below  illustrates that south of Monarch Creek all Ash Creek tributaries from the west have a northeast-orientation, indicating flood waters reaching the actively eroding north-oriented Ash Creek valley head flowed northeast, probably because the actively eroding Mizpah Creek valley had beheaded southeast-oriented flood flow to the Ash Creek valley further north. Northwest-oriented Mizpah Creek tributaries also captured water from yet to be beheaded (by Mizpah Creek valley headward erosion) flood water routes further to the south. For example, the north-oriented headwaters of northwest-oriented Forty Creek suggest reversed flow on the Forty Creek alignment captured yet to be beheaded flood flow on what is today the northwest-oriented Hercules Creek alignment.

Mizpah Creek-Ash Creek drainage divide area south

Figure 5: Mizpah Creek-Ash Creek drainage divide area south. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 5 illustrates the Mizpah Creek-Powder River drainage divide region south of the figure 4 map area and includes an overlap strip. Note how almost all Ash Creek tributaries from the west are northeast-oriented and how Ash Creek headwaters are also northeast-oriented. As previously mentioned this northeast-orientation suggests the Ash Creek valley was being eroded south by northeast-oriented flood waters captured from yet to be beheaded southeast-oriented flood flow routes south of the actively eroding Mizpah Creek valley head and the north-oriented Mizpah Creek valley had already eroded far enough south to have beheaded southeast-oriented flood flow routes that would have carried flood waters directly to the actively eroding Ash Creek valley head. Also note Maxwell Butte between northwest-oriented Spring Creek and northwest-oriented Elmhurst Creek and Twin Buttes along the Mizpah Creek-Ash Creek drainage divide. These buttes provide evidence of a higher level topographic surface upon which flood water once flowed. That topographic surface was at least as high as the butte tops and of flood waters first moving southeast and then being captured in sequence by headward erosion of the north-oriented Ash Creek valley and then headward erosion of the Mizpah Creek valley removed all of the surrounding material to produce the landscape that exists today. The north-oriented arc-shaped basin in the figure 5 southeast corner (the head of the north-oriented Ash Creek drainage basin) is an abandoned headcut, which was abandoned because the Spring Creek valley (southwest quadrant figure 5) was eroded deeper than the Ash Creek valley head, and when headward erosion of the north-oriented Mizpah Creek valley beheaded and reversed flood flow on that alignment there no longer was a source of flood water to what had been the actively eroding Ash Creek valley head (figure 6 will illustrate where the Spring Creek valley intersects the northeast-oriented Powder River valley, use Snake Butte for a reference point).

Mizpah Creek-Powder River drainage divide area west of Powderville

Figure 6: Mizpah Creek-Powder River drainage divide area west of Powderville. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 6 illustrates the Mizpah Creek-Powder River drainage divide region south of the figure 5 map area and includes an overlap strip. Spring Creek referred in te figure 5 discussion is located in figure 6 northeast quadrant west of southeast-oriented Meadow Creek headwaters. Mizpah Creek flows north along the northwest edge of the figure 6 map area. The Powder River here is northeast-oriented and flows in a deep valley located in the southeast corner of figure 6. Evidence for an initial southeast-oriented flood flow direction is easy to see in this figure 6 map region. Mizpah Creek tributaries are all northwest-oriented and there are through valleys at their valley heads linking the northwest-oriented Mizpah Creek tributaries with the short southeast-oriented Powder River tributaries. Events recorded by the figure 6 evidence begin with southeast-oriented flood flow moving across the entire region. Headward erosion of the deep northeast-oriented Powder River valley next captured the southeast-oriented flood flow, but before the southeast-oriented flood flow had time to erode deep southeast-oriented valleys headward into the newly eroded Powder River valley wall headward erosion of the shallower north-oriented Mizpah Creek valley captured the southeast-oriented flood flow and diverted the flood water north. Apparently the newly eroded Mizpah Creek valley was deep enough to cause a reversal of flood flow on the northwest ends of the beheaded southeast-oriented flood flow routes and those reversals of flood flow eroded the northwest-oriented Mizpah Creek tributary valleys that exist today. Note how northwest-oriented Corral Creek has a northeast-oriented tributary just east of Rattlesnake Hill. That northeast-oriented tributary is evidence reversed flood flow on the Corral Creek alignment captured yet to be beheaded flood flow still moving southeast on the more southerly Horse Creek alignment. Those captured flood waters helped erode the northwest-oriented Corral Creek valley.

Mizpah Creek-Powder River drainage divide area south of Powderville

Figure 7: Mizpah Creek-Powder River drainage divide area south of Powderville. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 7 illustrates the Mizpah Creek-Powder River drainage divide region south of the figure 6 map area and includes an overlap strip. The deep northeast-oriented Powder River valley is located along the figure 7 east edge. Mizpah Creek flows north across the figure 7 center. Note how short southeast-oriented tributaries flow to the northeast-oriented Powder River. Also note how nearly all Mizpah Creek flowing from the Mizpah Creek-Powder River drainage divide are northwest-oriented. Further, note the southeast-oriented Mizpah Creek tributaries from the west. Events recorded by the figure 7 evidence are similar to the events recorded by the figure 6 evidence. Southeast-oriented flood water initially flowed across the entire region and probably was eroding multiple ever-changing channels suggesting a southeast-oriented flood formed anastomosing channel complex. Headward erosion of the deep Powder River valley then captured the southeast-oriented flood flow, but before there was adequate time for the southeast-oriented flood waters to erode deep southeast-oriented valleys headward from the deep Powder River valley, headward erosion of the shallower Mizpah Creek valley captured the southeast-oriented flood flow. Flood waters on the northwest ends of the beheaded southeast-oriented flood flow routes (between the present day Mizpah Creek-Powder River drainage divide and the Mizpah Creek valley) reversed flow direction and flowed northwest to create northwest-oriented Mizpah Creek tributary valleys and also to create the present day Mizpah Creek-Powder River drainage divide.

Mizpah Creek-Powder River drainage divide area north of Broadus

Figure 8: Mizpah Creek-Powder River drainage divide area north of Broadus. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 8 illustrates the Mizpah Creek-Powder River drainage divide region south of the figure 7 map area and includes an overlap strip. Figure 8 evidence is very similar to the figure 6 and figure 7 evidence. The northeast-oriented Powder River flows across the figure 8 southeast corner in a deep valley that was eroded by headward erosion across southeast-oriented flood flow. Mizpah Creek in figure 8 is northeast-oriented and flows parallel to the much deeper northeast-oriented Powder River valley. Mizpah Creek tributaries from the Mizpah Creek-Powder River drainage divide are almost all northwest-oriented and tributaries from the west are almost all southeast-oriented. Powder River tributaries are short and are almost all southeast-oriented. Events recorded by the figure 8 are again similar to events recorded by the figure 6 and figure 7 evidence. Southeast-oriented flood flow moved across the entire region on a topographic surface at least as high as the highest figure 8 elevations today. Headward erosion of the deep Powder River valley captured that flood flow, but before there was time for southeast-oriented flood flow to erode deep southeast-oriented valleys into the Powder River valley wall, headward erosion of the shallower northeast-oriented Mizpah Creek valley captured the southeast-oriented flood flow and diverted the flood water north. Flood water already on the northwest ends of the beheaded southeast-oriented flood flow routes (between the Mizpah Creek valley and the present day Mizpah Creek-Powder River drainage divide) reversed flow direction to erode northwest-oriented Mizpah Creek tributary valleys. Very soon thereafter headward erosion of the north-oriented Pumpkin Creek valley further to the west captured the southeast-oriented flood flow to the north-oriented Mizpah Creek valley and rapid erosion ceased in the figure 8 region and the landscape has changed little since.

Mizpah Creek-Powder River drainage divide area west of Broadus

Figure 9: Mizpah Creek-Powder River drainage divide area west of Broadus. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 9 illustrates the Mizpah Creek-Powder River drainage divide region south of the figure 8 map area and includes an overlap strip. Figure 9 illustrates the south end of the north-oriented Mizpah Creek drainage basin. Mizpah Creek tributaries here are southeast-oriented and can be seen flowing southeast in the figure 9 northwest corner. The southeast-oriented Mizpah Creek headwaters are linked with northwest-oriented Pumpkin Creek tributaries. The East and West Forks of north-oriented Wolf Creek represent the southern most extensions of the Mizpah Creek drainage basin along the Powder River valley rim. Mizpah Creek headwaters are southwest of Epsie and will be show in figure 10 below. Figure 9 evidence otherwise is similar to figure 8 evidence and evidence also seen in figures 6 and 7. The Powder River flows northeast in a deep valley and Powder River tributaries from the west are short and southeast-oriented. Powder River tributaries from the east visible in figure 9 are also short and are northeast-oriented, but readers might want to look at the Powder River-Boxelder Creek drainage divide essay to better understand evidence east of the Powder River valley.  Mizpah Creek drainage flows north in a much shallower valley just west and northwest of the Powder River valley rim. Events recorded by the figure 9 evidence are similar to events previously described. One major difference along the figure 9 southwest corner edge is evidence of a deep southeast-oriented valley that was eroded into the northeast-oriented Powder River valley. Apparently at this point headward erosion of the deep northeast-oriented Powder River valley had progressed fast enough that headward of the Mizpah Creek valley could no longer behead southeast-oriented flood flow routes before they had an opportunity to erode deep valleys headward, which meant the shallower Mizpah Creek valley no longer could erode south.

Mizpah Creek-Powder River drainage divide area southwest of Broadus

Figure 10: Mizpah Creek-Powder River drainage divide area southwest of Broadus. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 10 illustrates the Mizpah Creek-Powder River drainage divide region southwest of the figure 9 map area and includes an overlap area. Figure 10 illustrates better the Mizpah Creek drainage basin south end and why the shallower north-oriented Mizpah Creek valley ceased to erode further south and southwest. Southeast-oriented Rock Springs Creek flows to southeast-oriented Cache Creek (unnamed on figure 10). Cache Creek and its various tributaries eroded deep southeast-oriented valleys headward into the northeast-oriented Powder River valley wall and directly captured southeast-oriented flood flow from west of the actively eroding north-oriented Mizpah Creek valley. When it was no longer possible to capture southeast-oriented flood flow further to the south and southwest active erosion of the Mizpah Creek valley head ceased and the Mizpah Creek headcut was abandoned. The north-oriented basin defined by the arc-shaped ridge of hills at the Mizpah Creek drainage basin head is what is left of the north-oriented headcut being eroded as the Mizpah Creek valley eroded south. This north-oriented abandoned headcut provides some clues as to the width and depth of the actively eroding Mizpah Creek valley head as it eroded south. Northwest-oriented drainage along the figure 10 west center edge are headwaters of northwest-oriented Dutchman Creek, which flow to a northwest oriented Pumpkin Creek valley segment. The north-oriented Pumpkin Creek valley beheaded southeast-oriented flood flow moving to the southeast-oriented Rock Spring Creek valley. Flood waters on the northwest end of that beheaded flood flow reversed flow direction to erode the northwest-oriented Dutchman Creek valley and the northwest-oriented Pumpkin Creek valley segment. Headward erosion of north-oriented Pumpkin Creek valley probably closely followed headward erosion of the deep northeast-oriented Powder River valley and the closely associated headward erosion of the shallower north-oriented Mizpah Creek valley and captured all flood flow moving across the figure 10 map area.

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.