A geomorphic history based on topographic map evidence

The Pumpkin Creek-Mizpah Creek drainage divide area discussed here is located in southeastern Montana, USA. Although detailed topographic maps of the Pumpkin Creek-Mizpah Creek 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 Pumpkin Creek-Mizpah Creek 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.

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 southeast Montana  Pumpkin Creek-Mizpah Creek 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 Pumpkin Creek-Mizpah Creek drainage divide area landform evidence will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm.

Pumpkin Creek-Mizpah Creek drainage divide general location map

Figure 1: Pumpkin Creek-Mizpah Creek drainage divide general location map. National Geographic Society map digitally presented using National Geographic Society TOPO software.

Figure 1 provides a general location map for the Pumpkin Creek-Mizpah Creek drainage divide area. Pumpkin Creek begins in southeast Montana near Sonnette and flows north-northeast until turning northwest to join a northwest-oriented Tongue River segment that flows to the northeast-oriented Yellowstone River. Mizpah Creek also begins in southeast Montana, near the Pumpkin Creek source area and flows northeast and then north to join a north-northwest-oriented Powder River segment, which flows to the northeast-oriented Yellowstone River. West of the Pumpkin Creek drainage basin is the north-northeast-oriented Tongue River drainage basin and east of the Mizpah Creek drainage basin is the northeast and north-northwest-oriented Powder River drainage basin. A different essay addresses landform evidence along the Mizpah Creek-Powder River drainage divide and can be found under Powder River on the sidebar category list. This essay interprets Pumpkin Creek-Mizpah Creek drainage divide area landforms to have originated during an immense southeast-oriented flood that was progressively captured by headward erosion of deep north-oriented valleys. In the case of drainage systems discussed here Powder River valley headward erosion was followed by Mizpah Creek valley headward erosion, which was followed by Pumpkin Creek valley headward erosion and shortly thereafter by Tongue River valley headward erosion. The flood water source cannot be determined from evidence provided here, although by using numerous other essays published on this website the flood waters can be traced headward into southern Alberta. Other essays also document how flood waters crossed the Powder River-Boxelder Creek drainage divide, the Boxelder Creek-Little Missouri River drainage divide, and the Little Missouri River-Moreau River drainage divide, among others, all located southeast of the northeast-oriented Powder River valley. Detailed maps presented here present evidence to demonstrate flood waters crossed the Pumpkin Creek-Mizpah Creek drainage divide and all rapid erosion of the Pumpkin Creek-Mizpah Creek drainage divide area ceased when the north-oriented Pumpkin Creek valley captured the southeast-oriented flood flow and diverted it to the northeast-oriented Yellowstone River.

Pumpkin Creek-Mizpah Creek drainage divide area detailed location map

Figure 2: Pumpkin Creek-Mizpah Creek 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 Pumpkin Creek-Mizpah Creek drainage divide area. The northeast-oriented Yellowstone River flows through Rosebud and Custer Counties in the figure 2 northwest quadrant. The north-northeast-oriented Tongue River flows north from Wyoming (not shown) into southeastern Rosebud County and then into southwest Custer County before turning northwest to join the Yellowstone River as a barbed tributary. Pumpkin Creek begins near Sonnette in Powder River County (just east of the Custer National Forest area) and flows north-northeast until it turns northwest to join the northwest-oriented Tongue River segment and flow to the northeast-oriented Yellowstone River near Miles City, Montana. The Powder River flows northeast from Wyoming and then northeast through Powder River County and enters southeast Custer County where it turns to flow north-northwest to the northeast-oriented Yellowstone River. Mizpah Creek begins west of Broadus in Powder River County a short distance east of the Pumpkin Creek source area and flows northeast and then north to join the north-northwest-oriented Powder River. Most tributaries to the north- and northeast-oriented trunk streams shown in figure 2 from the west are southeast-oriented and from the east are northwest-oriented. This southeast-northwest drainage alignment is evidence the north- and northeast-oriented trunk stream valleys were eroded headward to capture multiple southeast-oriented flood flow routes, such as might be found in a large southeast-oriented anastomosing channel complex. Northwest-oriented tributaries originated with reversals of flood flow on the northwest ends of beheaded southeast-oriented flood flow routes. Detailed maps in this essay further address this interpretation.

Pumpkin Creek-Powder River-Mizpah Creek north drainage divide

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

Figure 3 illustrates the north end of the Pumpkin Creek-Mizpah Creek drainage divide. Pumpkin Creek flows northwest across the figure 3 southwest quadrant. Mizpah Creek flows north along the figure 3 west edge and joins the north-northwest-oriented Powder River near the landing strip in the figure 3 northwest quadrant (the Powder River valley can be identified by the green color). East-oriented tributaries north of the Mizpah Creek-Powder River confluence flow directly to the Powder River. Note how many of the east-oriented tributaries are really southeast-oriented. Also note how Johnson Creek headwaters are southeast-oriented and Squaw Creek headwaters are northwest-oriented. Further, note how Pumpkin Creek is northwest-oriented. These southeast and northwest orientations are relics from the southeast-oriented flood water that flowed across the entire figure 3 map area. What was probably a deep north-oriented Powder River-Mizpah Creek valley eroded headward or south to capture multiple southeast-oriented flood flow routes and to divert the flood water north and north-northwest to the northeast-oriented Yellowstone River. Southeast and east-oriented tributary valleys eroded headward into the west wall of that newly eroded north-oriented Powder River-Mizpah Creek valley. Southeast-oriented flood water moving on what is today the northwest-oriented Pumpkin Creek-Tongue River alignment was next beheaded by headward erosion of the northeast-oriented Yellowstone River. Flood water already on the northwest end of that beheaded flood flow route reversed flow direction and started to flow northwest to the newly eroded and deeper northeast-oriented Yellowstone River valley. That new northwest-oriented flood flow eroded a deep valley headward or southeast and then south of figure 3 south-southwest to capture yet to be beheaded (by headward erosion of the north-northeast-oriented Tongue River valley and later by northeast-oriented Yellowstone River valley erosion) southeast-oriented flood flow.

Pumpkin Creek-Mizpah Creek drainage divide southeast of Johnson Creek

Figure 4: Pumpkin Creek-Mizpah Creek drainage divide southeast of Johnson Creek. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 4 illustrates the Pumpkin Creek-Mizpah Creek drainage divide southeast of the west-oriented Johnson Creek valley and includes significant overlap areas with figure 3. Pumpkin Creek in the figure 4 southwest quadrant is changing from being north-oriented to being northwest oriented. Mizpah Creek is flowing north along the figure 4 east edge. Note many Mizpah Creek tributaries flow southeast to join Mizpah Creek as barbed tributaries or have southeast-oriented segments and/or tributaries and that Pumpkin Creek has northwest oriented tributaries or tributaries with northwest-oriented headwaters. This southeast-northwest drainage alignment is a relic left from the southeast-oriented flood flow that initially flowed across the entire region prior to headward erosion of what was then the deep north-oriented Mizpah Creek valley and subsequently the deep northwest- and north-oriented Pumpkin Creek valley. Southeast and east-oriented Mizpah Creek tributary valleys were eroded headward by southeast-oriented flood waters. Pumpkin Creek west, southwest, and northwest-oriented tributary valleys along with the northwest-oriented Pumpkin Creek valley were eroded by reversed flow flood waters after headward erosion of the deep northeast-oriented Yellowstone River valley beheaded southeast-oriented flood flow routes across the figure 4 map region. The deep Pumpkin Creek valley eroded south to capture yet to be beheaded (by headward erosion of the north-northeast-oriented Tongue River valley and subsequently by the northeast-oriented Yellowstone River valley) southeast-oriented flood flow routes further to the south. Figure 4 evidence also suggests reversed flow on some west-oriented Pumpkin Creek tributaries captured flood waters from yet to be beheaded (by headward erosion of the Pumpkin Creek valley) southeast-oriented flood flow further to the south. For example the South Fork valley of Second Creek was probably eroded when reversed flood flow on the Second Creek alignment captured flood waters from yet to beheaded flood flow still moving on the Third Creek alignment.

Pumpkin Creek-Mizpah Creek drainage divide east and southeast of Beebe

Figure 5: Pumpkin Creek-Mizpah Creek drainage divide east and southeast of Beebe. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 5 illustrates the Pumpkin Creek-Mizpah Creek drainage divide area east and southeast of the former town of Beebe and includes an overlap strip with figure 4. Pumpkin Creek flows north-northeast across the figure 5 west half and Mizpah flows north-northeast across the figure 5 east half. Mizpah Creek tributaries from the west are almost all southeast-oriented and their valleys were eroded headward into the west wall of what was then the newly eroded and deep north-oriented north-northeast-oriented Mizpah Creek valley. Pumpkin Creek tributaries from the east are almost all northwest-oriented and were eroded southeast by reversed flow on the northwest ends of southeast-oriented flood flow routes beheaded by headward erosion of the deep north-northeast-oriented Pumpkin Creek valley. Note how major northwest-oriented Pumpkin Creek tributaries have northeast-oriented tributaries. Those northeast-oriented tributaries are evidence reversed flow on each northwest-oriented tributary valley captured yet to be beheaded (by headward erosion of deep Pumpkin Creek valley) southeast-oriented flood water moving along the alignment of the present day northwest-oriented tributary to the south. In other words the northwest-oriented tributary valleys were eroded in a progressive sequence as the Pumpkin Creek valley eroded south, and reversed flow on each major beheaded flood flow  route captured yet to be beheaded flood water from the yet to be beheaded major flood flow route just to the southeast. In addition to the drainage alignment and evidence of flood water captures by reversed flow on the northwest ends of beheaded flood flow routes a close look at figure 5 evidence also shows shallow through valleys or gaps or passes eroded in the drainage divide linking the northwest-oriented streams and the southeast-oriented streams. These through valleys are further evidence southeast-oriented flood waters moving on a high level topographic surface at least as high as the highest points along the Pumpkin Creek-Mizpah Creek drainage once flowed across the region and the drainage divide was created when headward erosion of the deep north-northeast-oriented Pumpkin Creek valley beheaded southeast-oriented flood flow and caused flood waters on the northwest ends of those beheaded flood flow routes to reverse flow direction.

Pumpkin Creek-Mizpah Creek drainage divide east and northeast of Volborg

Figure 6: Pumpkin Creek-Mizpah Creek drainage divide east and northeast of Volborg. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 6 illustrates the Pumpkin Creek-Mizpah Creek drainage divide area east and northeast of Volborg and does not include an overlap strip. Figure 6 evidence is very similar to the figure 5 evidence with the exception that the northeast-oriented Sand Creek valley eroded southwest to capture southeast-oriented flood water that had been flowing to the north-oriented Mizpah Creek valley. Note how southeast-oriented tributaries flowing to the north-oriented Mizpah Creek valley are relatively shallow suggesting headward erosion of the northeast-oriented Sand Creek valley beheaded southeast-oriented flood flow routes to what was then the newly eroded north-oriented Mizpah Creek valley before those southeast-oriented flood flow routes had time to erode deep valleys into the newly eroded and deep Mizpah Creek valley west wall. Likewise southeast-oriented Sand Creek tributary valleys are shallow probably because headward erosion of the north-oriented Pumpkin Creek valley beheaded southeast-oriented flood flow to what was then the newly eroded Sand Creek valley before there was time for southeast-oriented flood flow to erode deep valleys into what was then the newly eroded Sand Creek northwest valley wall. Note how northwest-oriented Deer Creek (flowing to north-oriented Pumpkin Creek) is linked by through valleys with the northwest-oriented Sand Creek drainage basin. Those through valleys are evidence that prior to Pumpkin Creek valley headward erosion significant southeast-oriented flood flow was moving into what was then the newly eroded and deep northeast-oriented Sand Creek valley along the present day Deer Creek alignment. That southeast-oriented flood flow route was beheaded and reversed by headward erosion of the deeper Pumpkin Creek valley to erode the northwest-oriented Deer Creek valley. Also note the north-oriented Deer Creek tributary valley linked to the northwest-oriented Shelter Creek valley further to the south. That north-oriented Deer Creek tributary valley was probably eroded by yet to be beheaded flood waters (by headward erosion of the north-oriented Pumpkin Creek valley) flowing southeast on the present-day Shelter Creek alignment to the actively eroding northeast-oriented Sand Creek valley.

Pumpkin Creek-Mizpah Creek drainage divide in Coalwood area

Figure 7: Pumpkin Creek-Mizpah Creek drainage divide in Coalwood area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 7 illustrates the Pumpkin Creek-Mizpah Creek drainage divide area in the Coalwood vicinity and includes an overlap strip with figure 6. Mizpah Creek flows north-northeast along the figure 7 east edge and Pumpkin Creek flows north-northeast along the figure 7 west edge. Mizpah Creek tributaries from the west are southeast-oriented and Pumpkin Creek tributaries from the east are northwest-oriented. Note well-defined through valleys linking northwest-oriented Pumpkin Creek tributaries with southeast-oriented Mizpah Creek tributaries. For example a well-defined through valley at Coalwood links northwest-oriented S L Creek with southeast-oriented Hay Creek. These through valleys are evidence southeast-oriented flood water flowed across the Pumpkin Creek-Mizpah Creek drainage divide prior to headward erosion of the north-oriented Pumpkin Creek valley and that headward erosion of the Pumpkin Creek valley beheaded the southeast-oriented flood flow routes and caused reversals of flood flow on northwest ends of the beheaded flow routes. Those reversals of flood flow not only eroded the northwest-oriented valleys but also created the Pumpkin Ceek-Mizpah Creek drainage divide. Also note through valleys that indicate reversed flood flow on beheaded flood flow routes captured flood waters from yet to be beheaded (by Pumpkin Creek valley headward erosion) southeast-oriented flood flow routes further south. For example, northwest of Coalwood an unnamed northwest-oriented Pumpkin Creek tributary is linked by a large well-defined through valley with northwest-oriented S L Creek. That through valley probably carried yet to be beheaded flood waters to reversed flood flow on what was then a newly beheaded southeast-oriented flood flow route that had been eroding the southeast-oriented Hay Creek valley northwest from the north-northeast-oriented Mizpah Creek valley.

Pumpkin Creek-Mizpah Creek drainage divide northwest of Olive

Figure 8: Pumpkin Creek-Mizpah Creek drainage divide northwest of Olive. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 8 illustrates the Pumpkin Creek-Mizpah Creek drainage divide area northwest of Olive and includes an overlap area strip with figure 7. Mizpah Creek flows northeast across the figure 8 southeast corner while Pumpkin Creek flows north-northeast across the figure northwest corner. Again Mizpah Creek tributaries from the west are southeast-oriented and Pumpkin Creek tributaries from the east are northwest-oriented. Through valleys link the headwaters of the southeast-oriented Mizpah Creek tributaries with headwaters of the northwest-oriented Pumpkin Creek tributaries. The northwest-southeast oriented drainage alignment and the through valleys are evidence southeast-oriented flood waters using multiple southeast-oriented flow routes or channels, such as might be found in a southeast-oriented anastomosing channel complex, flowed across the region prior to headward erosion of the north-northeast-oriented Pumpkin Creek valley. Headward erosion of the deep north-northeast-oriented Pumpkin Creek valley beheaded the southeast-oriented flood flow routes in sequence, causing reversals of flood flow on the northwest ends of the beheaded flood flow routes. Those reversals of flood flow aided by flood waters captured from yet to be beheaded (by Pumpkin Creek valley headward erosion) southeast-oriented flood flow routes further to the south eroded northwest-oriented tributary valleys to the newly eroded Pumpkin Creek valley and also created the present day Pumpkin Creek-Mizpah Creek drainage divide. Flood waters were subsequently captured by headward erosion of the deep north-northeast-oriented Tongue River valley to the west and rapid erosion of figure 8 region ceased.

Pumpkin Creek-Mizpah Creek drainage divide northwest of Epsie

Figure 9: Pumpkin Creek-Mizpah Creek drainage divide northwest of Epsie. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 9 illustrates the Pumpkin Creek-Mizpah Creek drainage divide area northwest of Epsie and includes an overlap area with figure 8. Figure 9 illustrates the south end of the Mizpah Creek drainage basin. Mizpah Creek originates southwest of Epsie near Mc Allister Butte. Pumpkin Creek flows northwest across he figure 8 southwest corner and flows northeast across the figure 8 northwest corner. The northwest-oriented Pumpkin Creek valley and its northwest-oriented Dutchman Creek and Reservoir Creek tributaries provide evidence headward erosion of the Pumpkin Creek valley beheaded a southeast-oriented flood flow route carrying flood water directly to the deep northeast oriented Powder River valley. That southeast-oriented flood flow channel must have been eroded deep enough that the north-northeast oriented Mizpah Creek valley could not capture the flood flow moving in it, and for that reason headward erosion of the north-northeast oriented Mizpah Creek valley ceased. When Pumpkin Creek beheaded that direct southeast-oriented flood flow route to the Powder River valley, flood waters on the northwest end of the beheaded flood flow route reversed flow direction to flow northwest to the newly eroded northeast- and north-oriented Pumpkin Creek valley. As will be noted in figure 10 the Pumpkin Creek valley did continue to erode a short distance south from this figure 9 location to capture a few more southeast-oriented flood flow routes. Note how the north-northeast-oriented Mizpah Creek valley continued to capture southeast-oriented flood flow routes almost all the way south and southwest to its head.

Pumpkin Creek-Powder River-Mizpah Creek south drainage divide

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

Figure 10 illustrates the Pumpkin Creek-Powder River drainage divide and the south end of the Pumpkin Creek-Mizpah Creek drainage divide and includes significant overlap areas with figure 9. The north-northeast-oriented basin located in the figure 10 northeast corner is the abandoned north-northeast-oriented Mizpah Creek headcut that was actively being eroded as the Mizpah Creek valley eroded south-southwest. This abandoned headcut provides some clues as to magnitude of the erosion that took place and also as to how the entire Pumpkin Creek-Mizpah Creek drainage divide region was eroded starting with flood flow moving southeast on a topographic surface at least as high as the highest elevations in the Pumpkin Creek-Mizpah Creek drainage divide region today. Immense headcuts such as this abandoned Mizpah Creek headcut were eroded headward across and along flood flow routes to produce the landscape present today. Northeast and southeast-oriented Cache Creek in the figure 10 southeast corner and its southeast-oriented tributaries are flowing to the deep northeast-oriented Powder River valley located just east of the figure 10 southeast corner. Figure 10 better illustrates the Pumpkin Creek headwaters than figure 9. Like the Mizpah Creek valley the Pumpkin Creek valley continued to erode south until it could not capture southeast-oriented flood flow from a deeper flood flow channel. That deeper flood flow channel had been eroded headward along a major flood flow route from the deep northeast-oriented Powder River valley. Subsequently headward erosion of the Tongue River-Otter Creek valley west of the Pumpkin Creek valley beheaded that deeper southeast-oriented flood flow route to create the present day Otter Creek (Tongue River)-Powder 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.