A geomorphic history based on topographic map evidence

Abstract:

The Beaver Creek-Birch Creek drainage divide area is located in Hill and Chouteau Counties, Montana, USA and includes high Bear Paw Mountain regions.Beaver Creek is a north oriented Milk River tributary and Birch Creek is a south-oriented Missouri River tributary. Although detailed topographic maps of the Beaver Creek-Birch 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 Beaver Creek-Birch 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 across the drainage divide ended when headward erosion of the Milk River valley captured all southeast-oriented flood flow.

Preface:

Introduction:

• The purpose of this essay is to use topographic map interpretation methods to explore Beaver Creek-Birch Creek drainage divide area landform origins in Hill and Chouteau Counties, Montana. 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 Beaver Creek-Birch Creek drainage divide area landform evidence in Hill and Chouteau Counties, Montana will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm.

Beaver Creek-Birch Creek drainage divide area location map

Figure 1: Beaver Creek-Birch Creek 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 Beaver Creek-Birch Creek drainage divide area location map. Figure 1 illustrates a region in north central Montana and the US-Canada border is located just north of the figure 1 north edge. The Missouri River flows northeast, southeast, east-northeast, and southeast from the figure 1 west edge to Fort Peck Lake, which continues to the figure 1 east edge. The lake is a large reservoir impounded behind Fort Peck Dam, which is located east of the figure 1 map area. The Milk River flows southeast from Canada (in the figure 1 northwest corner) to Fresno Reservoir, Havre, Chinook, Harlem, Dodson, and Wagner. Beaver Creek (unnamed in figure 1) originates in the Bears Paw Mountains and flows in a north and north-northwest direction to join the east-oriented Milk River near Havre. Birch Creek is also unnamed in figure 1 and originates immediately south of the “e” in the words “Bears Paws Mts.” and flows in a south-southwest, southeast, and finally southwest direction to join the southeast-oriented Missouri River. The Beaver Creek-Birch Creek drainage divide area discussed here is located in the high Bear Paw Mountains and is in reality the Milk River-Missouri River drainage divide area. The eastern boundary of the Milk River-Missouri River drainage divide area discussed in this essay is Clear Creek, which flows north to join the Milk River east of Havre. The Milk River-Peoples Creek drainage divide area and the Peoples Creek-Missouri River drainage divide area essays describe drainage divide areas located immediately east of north-oriented Clear Creek and can be found under Milk River on the sidebar category list. Evidence presented in those essays demonstrated the present day north-oriented Clear Creek valley in the Bear Paw Mountain highlands region initially had been eroded by south-oriented flood flow, which was subsequently reversed to flow in a north direction when headward erosion of the deep east- and southeast-oriented Milk River valley beheaded and reversed the south-oriented flood flow route. Based on evidence from other Milk River drainage basin drainage divide area essays and evidence observable on detailed topographic maps shown below, landform evidence illustrated here is interpreted in the context of an immense south-oriented flood flowing across the figure 1 map area, including high Bear Paw Mountain regions, and which was systematically beheaded by Milk River valley headward erosion. As the Milk River valley eroded northwest and west it captured southeast-oriented flood water moving on a topographic surface at least as high as the topographic surface now preserved in the high Bear Paw Mountains to what was then the deep and newly eroded Missouri River valley. Flood waters on the ends of beheaded south-oriented flood flow routes reversed flow direction and eroded the present day north-oriented Milk River tributary valleys. Detailed maps below show how reversed flow in the present day north-oriented valleys captured south-oriented flood waters from adjacent yet to be beheaded (by deep Milk River valley headward erosion) south-oriented flood flow routes.

Beaver Creek-Birch Creek drainage divide area detailed location map

Figure 2: Beaver Creek-Birch Creek 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 Beaver Creek-Birch Creek drainage divide area discussed in this essay. Hill, Blaine and Chouteau Counties are located in Montana. The eastern red shaded area is the Fort Belknap Indian Reservation and the western red shaded area is the Rocky Boys Indian Reservation. The Milk River flows southeast from the figure 2 north edge to Havre and then east and southeast to the figure 2 east edge. The Missouri River flows northeast and south-southeast in the figure 2 southwest quadrant and then forms the southern boundary of Chouteau and Blaine Counties in the figure 2 lower half. Beaver Creek flows north and northwest from the Bear Paw Mountains to join the east-oriented Milk River as a barbed tributary. East of Beaver Creek is north and northwest-oriented Bullhook Creek and north-northeast and northwest-oriented Little Boxelder Creek. East of Little Boxelder Creek is north-oriented Clear Creek. The Beaver Creek-Birch Creek drainage divide area discussed here includes evidence from the region between Beaver Creek and Clear Creek. Birch Creek originates near the Beaver Creek headwaters (near Baldy Mountain at the south edge of the Rocky Boys Indian Reservation) and flows south, southeast, and southwest to join the east-oriented Missouri River. As previously mentioned this essay interprets Beaver Creek-Birch Creek drainage divide evidence in the context of an immense southeast oriented flood, which crossed the figure 2 map area. Headward erosion of the east-oriented Missouri River valley first captured the southeast and south-oriented flood flow. Soon thereafter headward erosion of the Milk River valley beheaded southeast-oriented flood flow routes to the newly eroded Missouri River valley. Topographic maps below illustrate how southeast-oriented Missouri River tributary valleys eroded north into the Bear Paw Mountain region to capture south- and southeast-oriented flood flow, which was subsequently beheaded by headward erosion of the deep Milk River valley. Evidence presented requires flood waters to have flowed across a topographic surface at least as high as the highest figure 2 elevations today (including Bear Paw Mountain elevations), although it is possible the Bear Paw Mountains region was being uplifted while flood erosion was taking place. An alternate possibility is the Bear Paw Mountains region and the Beaver Creek-Birch Creek drainage divide area were surrounded by sedimentary rocks and/or ice, which were removed by flood water erosion. Detailed maps tell the story better.

North end of the Beaver Creek-Birch Creek drainage divide area

Figure 3: North end of the Beaver Creek-Birch Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 3 illustrates the north end of the Beaver Creek-Birch Creek drainage divide area discussed in this essay. The east oriented Milk River is located in the figure 3 north half. North-northwest and northeast oriented Beaver Creek is located along the figure 3 west edge and joins the Milk River west of Havre. North- and northwest oriented Bullhook Creek flows from the figure 3 south edge to join the Milk River at Havre. Northeast, northwest, and northeast-oriented Little Boxelder Creek joins the Milk River at the roadside park area east of Havre. Clear Creek flows north-northeast along the figure 3 east edge to join the Milk River near Lohman. The digital map set being used for these essays unfortunately has Bear Paw Mountain maps without contour lines at this scale. Two maps at this scale are included in this essay to show big picture drainage relationships, otherwise the essay uses more detailed maps with contour lines. North-oriented Milk River tributaries are flowing from the Bear Paw Mountains region to the south and elevations where the streams join the Milk River are significantly lower than Bear Paw Mountains elevations shown in the following maps (e.g. the Milk River valley floor at Havre is slightly less than 2500 feet and the Little Boxelder Creek-Birch Creek drainage divide seen in figure 7 below is slightly less than 5200 feet). Note northwest-orientations of segments of each of the north-oriented valleys. These northwest-orientations are relics of southeast oriented flood flow routes beheaded by headward erosion of the deep Milk River valley. Flood waters on the northwest ends of beheaded southeast and south-oriented flood flow routes reversed flow direction to erode the northwest-oriented valley segments and in this region to also erode the north-oriented valley segments. Evidence presented in the Milk River-Peoples Creek drainage divide essay and the Peoples Creek-Missouri River drainage divide essay indicated the north-oriented Clear Creek valley (south of the figure 3 map area) was initiated by south-oriented flood flow and was subsequently reversed when headward erosion of the deep east and southeast-oriented Milk River valley beheaded the south-oriented flood flow route. Figures below demonstrate the Beaver Creek and Little Boxelder Creek valleys in the high Bear Paw Mountains regions south of figure 3 also originated as south-oriented flood flow routes and were also beheaded and reversed by headward erosion of the deep east-oriented Milk River valley. At the time south-oriented flood waters crossed the Bear Paw Mountains present day topography did not exist. There was no east-oriented Milk River valley and it is possible Bear Paw Mountain uplift took place as flood waters eroded the region.

Drainage routes in high Bear Paw Mountains

Figure 4: Drainage routes in high Bear Paw Mountains. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 4 is the second of the two digital maps lacking contour lines and is shown to illustrate drainage system relationships in the high Bear Paw Mountains south of the figure 3 map area. North-oriented Beaver Creek is formed where the West Fork and East Fork meet just north of Baldy Mountain in the figure 4 center and flows to the figure 4 north center edge. The West Fork Beaver Creek is aligned with southwest Eagle Creek, which flows southwest along the northwest side of Pecora Ridge and then southwest to the figure 4 south edge (west half). Eagle Creek eventually reaches the Missouri River. Flowing south from the East Fork headwaters area (east of Baldy Mountain) is the West Fork of Birch Creek. The West Fork Birch Creek flows south to join the southwest-oriented East Fork and then reach the figure 4 south edge. Eventually Birch Creek reaches the Missouri River. North and slightly east of the West Fork Birch Creek headwaters area are headwaters of north-oriented Little Boxelder Creek, which flows to the figure 4 north edge and continues north to the Milk River as seen in figure 3. Further east in the figure 4 northeast corner area is north and north-northwest oriented Clear Creek, which also continues north to the Milk River. West of the Beaver Creek headwaters are headwaters of Big Sandy Creek, which flows around Black Mountain and then northwest and southwest. Big Sandy Creek eventually makes a complete U-turn west of the Bear Paw Mountains to flow north and northeast to the east-oriented Milk River valley. Detailed maps with contour lines below illustrate drainage divides in this high mountain region and then follow Birch Creek downstream towards the Missouri River. North-oriented Clear Creek, Little Boxelder Creek, and Beaver Creek have all eroded significant north-oriented valleys into what is today a substantial north-facing slope. A valid question is, if the flood that crossed the Bear Paw Mountains was south-oriented, where did the water come from that eroded the north-oriented valleys and slope? Headward erosion of the deep east-oriented Milk River beheaded south-oriented flood flow routes in sequence from east to west, which meant after south-oriented flood flow on the Clear Creek valley was beheaded and reversed south-oriented flood flow continued on the Little Boxelder Creek and Beaver Creek alignments and when flood flow on the Little Boxelder Creek alignment was beheaded and reversed south-oriented flood flow still continued on the Beaver Creek alignment. The flood flow channels were interconnected, which meant reversed flow on the Clear Creek alignment could capture non-reversed flood flow from south-oriented flood flow routes further to the west. Figure 5 below illustrates one such capture location along the West Fork of Clear Creek, located in the figure 4 northwest quadrant. Figure 6 illustrates another such area of capture along the present day Big Sandy Creek-Beaver Creek drainage divide.

Little Boxelder Creek-Clear Creek drainage divide area

Figure 5: Little Boxelder Creek-Clear Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 5 illustrates the Little Boxelder Creek-Clear drainage divide area and the White Pine Canyon and West Fork Clear Creek through valleys linking the two north-oriented streams. North-northwest oriented Clear Creek is located along the figure 5 east edge. North-oriented Little Boxelder Creek is located near the figure 5 west edge. Northeast-oriented White Pine Canyon is located in the figure 5 north center area and drains to Clear Creek north of the figure 5 map area. East and northeast-oriented West Fork Clear Creek is located in the figure 5 southeast quadrant. Note the through valleys linking headwaters of  northeast-oriented White Pine Canyon with a northwest-oriented Little Boxelder Creek tributary valley and linking headwaters of east and northeast-oriented West Fork Clear Creek with the north-oriented Little Boxelder Creek valley. Perhaps the easiest one to understand is the West Fork Clear Creek through valley, although the White Pine Canyon valley history is the same (except it was abandoned before the West Fork Clear Creek through valley was abandoned). The West Fork Clear Creek through valley was eroded by flood water moving south along what is now the north-oriented Little Boxelder Creek valley, although previous to that time it had probably been eroded as a channel in an ever-changing south-oriented anastomosing channel complex eroded into the present day Bear Paw Mountains upland surface and it is possible at one time the West Fork Clear Creek valley may have carried west-oriented flood water. In any case, when headward erosion of the deep east and southeast-oriented Milk River valley (to the north) beheaded and reversed the south-oriented Clear Creek valley flood flow, south-oriented flood flow on the Little Boxelder Creek valley flood flow route had not yet been beheaded and continued to flow into the figure 5 map region. The West Fork Clear Creek valley already existed and quickly became a route south-oriented flood flow in the Little Boxelder Creek could use to move to the newly reversed Clear Creek valley, which had suddenly become north-oriented to flow to the much deeper east-oriented Milk River valley. Flood waters also continued to flow south in the Little Boxelder Creek valley to the Little Boxelder Creek-Birch Creek drainage divide seen in figure 7 and 8 below.

Big Sandy Creek-Beaver Creek drainage divide area

Figure 6 illustrates the Big Sandy Creek-Beaver Creek drainage divide area. North-northwest oriented Beaver Creek is located in the figure 6 northeast quadrant and the northeast-oriented West Fork Beaver Creek is located in the figure 6 southeast quadrant. Big Sandy Creek flows around Klhiw Ridge in the figure 6 southwest quadrant. North-oriented Boxelder Creek is located in the figure 6 north center area. Note the well-defined through valley linking the present day west-oriented Big Sandy Creek valley with the northeast-oriented West Fork Beaver Creek valley. The through valley provides evidence water once flowed across the Big Sandy Creek-Beaver Creek drainage divide. Figures 7 and 8 below present evidence water once flowed south in the Beaver Creek valley to both the southwest-oriented Eagle Creek valley and the south-oriented Birch Creek valley and then the south-oriented Beaver Creek flood flow route was beheaded and reversed to create the present day north-oriented Beaver Creek drainage system. The present day Beaver Creek drainage system was eroded by significant amounts of north-flowing water and some of that water probably flowed east along the present day Big Sandy Creek valley alignment. At the time headward erosion of the Milk River valley beheaded and reversed south-oriented flood flow on the Beaver Creek alignment south-oriented flood flow was still moving into what is now the Big Sandy Creek drainage basin further to the west. At that time flood waters were flowing on a topographic surface at least as high as the highest figure 6 elevations. It is possible the high topographic surface was in part on top of a decaying ice sheet mass. Whatever created that high level topographic surface the surface has since been removed by flood water erosion, melting of ice (if ice was present), and/or Bear Paw Mountain uplift. In any case south-oriented flood waters entering the present day Big Sandy Creek drainage basin area were captured by reversed flood flow in the present day West Fork Beaver Creek valley and moved east along the present day Big Sandy Creek headwaters water. Subsequently headward erosion of the Milk River valley beheaded and reversed south-oriented flood flow routes in the Big Sandy Creek drainage basin and flow in the Big Sandy Creek headwaters valley was reversed to flow west.

Beaver Creek-Birch Creek drainage divide area

Figure 7: Beaver Creek-Birch Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 7 uses reduced maps to show the Beaver Creek-Birch Creek drainage divide area and also the Little Boxelder Creek-Birch Creek drainage divide area and includes overlap areas with both figures 5 and 6. The West Fork Clear Creek is located in the figure 7 northeast quadrant and north-oriented Little Boxelder Creek flows to the figure 7 north center edge. The northeast-oriented West Fork and northwest-oriented East Fork join to form north-oriented Beaver Creek in the figure 7 northwest corner area. The East Fork Birch Creek originates in the figure 7 center area and flows south to the figure 7 south center edge. The West Fork Birch Creek originates in the figure 7 center east area and flows south, southeast, and south in the figure 7 southeast quadrant. Note the through valleys in the figure 7 center area linking headwaters of the northwest-oriented East Fork Beaver Creek with south-oriented West Fork Birch Creek, north-oriented Little Boxelder Creek with south-oriented West Fork Birch Creek, and also the northwest-oriented West Fork Beaver Creek with north-oriented Little Boxelder Creek. These and other similar through valleys provide evidence south-oriented flood waters from the present day north-oriented Little Boxelder Creek and Beaver Creek valleys flowed south to erode the south-oriented Birch Creek valley headward from the deep Missouri River valley (located south of the figure 7 map area). Similar through valleys link the south-oriented East Fork Birch Creek with headwaters of unnamed northeast-oriented Clear Creek tributaries in the figure 7 east center area. The through valleys also provide evidence south-oriented flood flow in the Beaver Creek valley moved east to flow north in the Little Boxelder Creek valley. A close look at the figure 7 map reveals a maze of through valleys at different elevations suggesting the presence of an ever-changing south-oriented anastomosing channel complex that was systematically beheaded and reversed to create the present day Milk River-Missouri River drainage divide and to erode the present day north-oriented Milk River tributary valleys.

Beaver Creek-Eagle Creek drainage divide area

Figure 8: Beaver Creek-Eagle Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 8 uses reduced maps to illustrate the Beaver Creek-Eagle Creek drainage divide area and its relationship to the Beaver Creek-Birch Creek drainage divide and includes overlap areas with figure 7 above.  Baldy Mountain is located in the figure 8 center. North of Baldy Mountain is the northeast-oriented West Fork Beaver Creek, which near the figure 8 north edge joins northwest-oriented East Fork Beaver Creek to form north oriented Beaver Creek. North-oriented Little Boxelder Creek is located in the figure 8 northeast corner and south-oriented West Fork Birch Creek flows through the figure 8 southeast corner area. Headwaters of southwest-oriented Eagle Creek are located west of Baldy Mountain and Eagle Creek flows southwest to the figure 8 southwest corner. Eagle Creek continues to flow southwest from the figure 8 map area to eventually join a south-oriented Missouri River valley segment (see figures 1 and 2). South and southeast-oriented Birch Creek flows to an east-oriented Missouri River valley segment. The orientation of the Eagle Creek and Birch Creek valleys in the high Bear Paw Mountains is probably related to the orientations of those Missouri River valley segments. The deep Missouri River valley eroded south of the Bear Paw Mountains and the Missouri River’s ability to erode deep north and northwest-oriented valleys into the Bear Paw Mountain bedrock was limited and no deep southeast-oriented or south-oriented valleys could be eroded across the Bear Paw Mountains. However, when headward erosion of the deep Missouri River valley head reached the west end of Bear Paw Mountains suddenly it was free to erode a deep valley north and northwest and then headward along the Bear Paw Mountain west flank. That sharp change in the Missouri River valley orientation can be seen in figures 1 and 2. Headward erosion of the deep east-oriented Milk River valley north of the Bear Paw Mountains then beheaded and reversed south-oriented flood flow along the Bear Paw Mountain west flank to create north and northeast-oriented Big Sandy Creek valley segments. However, southwest-oriented  Big Sandy Creek valley segments west of the Beaver Creek-Birch Creek drainage divide area discussed here eroded headward from a rapidly eroding south-oriented Missouri River tributary valley that was subsequently beheaded and reversed by Milk River valley headward erosion. [Immense quantities of flood water subsequently deepened the Missouri River valley south of the Bear Paw Mountains region so the Missouri River tributary valley that initially eroded north along the Bear Paw Mountains west flank was probably at much higher elevation than the present day north-oriented Big Sandy Creek valley.]

Hattie Creek and East Fork Birch Creek-Rhue Creek drainage divide area

Figure 9: Hattie Creek and East Fork Birch Creek-Rhue Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 9 illustrates the Hattie Creek and East Fork Birch Creek-Rhue Creek drainage divide area south of the figures 7 and 8 map areas. The West Fork Birch Creek is located in the figure 9 northwest quadrant and flows southwest and south to join the southwest-oriented East Fork Birch Creek in the figure 9 west center area and then flow south. The East Fork Birch Creek flows southwest from the figure 9 north center edge. Hattie Creek flows southwest and northwest to join the East Fork Birch Creek in the figure 9 north center area. Rhue Creek flows south and southwest from the figure 9 center area to join south-oriented Birch Creek south of the figure 9 map area. South-oriented Sand Creek is located along the figure 9 east edge. Note the north-south through valley linking Hattie Creek at its elbow capture with the south-oriented Rhue Creek headwaters. There is a north-oriented Hattie Creek tributary flowing at the north end of that valley. Also note that valley is just one of several possible north-south through valleys linking the Hattie Creek elbow of capture with the Rhue Creek valley. These through valleys and others like them provide evidence of a maze of anastomosing channels, which provides evidence of south-oriented flood flow. Figures 7 and 8 above illustrate the East Fork and West Fork Birch Creek headwaters areas and their linkages with the present day north-oriented Beaver Creek and Little Beaver Creek valleys. Yet the south-oriented slope leading to the Missouri River is a maze of abandoned anastomosing channels, providing evidence an immense south-oriented flood once moved across the present day Bear Paw Mountains to what was probably at that time the newly eroded east-oriented Missouri River valley. The Bear Paw Mountains region may have been uplifted as the flood eroded the region or the present day Bear Paw Mountains elevation above the surrounding region may have developed as flood waters removed surrounding materials (which may have included ice).

Birch Creek-West Fork Sand Creek drainage divide area

Figure 10: Birch Creek-West Fork Sand Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 10 illustrates the Birch Creek-West Fork Sand Creek drainage divide area south of the figure 9 map area. Birch Creek flows south-southwest and south in the figure 10 west half. The West Fork Sand Creek originates east of Rattlesnake Butte (located in the figure 10 center west) and flows east and south-southeast to the figure 10 south center (east) edge and joins Sand Creek south of the figure 10 map area. Little Sand Creek flows south-southwest from the figure 10 northeast quadrant and then south-southeast to the figure 10 southeast quadrant. Southwest and south-oriented Sand Creek flows from the figure 10 east center edge and is joined by south-southeast oriented Little Sand Creek south of the figure 10 south edge. Sand Creek is a Birch Creek tributary and eventually joins Birch Creek south of the figure 10 map area. Note the through valleys linking the West Fork Sand Creek valley with the Birch Creek valley (for example north of Rattlesnake Butte). Also note through valleys linking the Little Sand Creek valley and the West Fork Sand Creek valleys and linking the Little Sand Creek valley with the Sand Creek valley. This maze of through valleys is more evidence of the anastomosing channel complex south-oriented flood waters carved into the Bear Paw Mountains south flank. These flood waters flowed across what is today a high mountain region. To some extent the Bear Paw Mountain region elevation is the result of the erosion of deep valleys around it. Some of the present day elevation probably resulted from localized uplift, which may have been taking place as flood waters eroded the region. The source of the southeast-oriented flood waters cannot be determined from evidence presented in this here. However, the hundreds of Missouri River drainage basin landform origins research project essays published on this website when taken as a group can be used to trace flood waters both up flood to source areas and down flood to see where flood waters were going. A logical flood water source would be rapid melting of a thick North American ice sheet located in a deep “hole” occupying approximately the North American location usually recognized to have been glaciated. The deep “hole” would have been created by deep glacial erosion and by crustal warping caused by the ice sheet weight. Such a flood water source would not only explain the immense southeast-oriented floods this essay series describes, but would also explain why deep valleys were eroding headward to capture the southeast-oriented flood waters and diverting the flood waters further and further to the northeast and north into space in the deep “hole” the rapidly melting thick ice sheet had once occupied. In addition, such a flood water source may explain uplift of the Bear Paw Mountains region during an immense southeast-oriented flood. A thick North American ice sheet in deep “hole” created in part due to the ice sheet’s weight would probably create crustal warping elsewhere on the continent, especially along ice sheet margins. Further, rapid erosion of significant volumes of overlying material might trigger localized uplifts of what are today high mountain regions.

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.