Montana Teton River drainage basin landform origins, overview essay

Authors

A geomorphic history based on topographic map evidence

Abstract:

This is an overview essay for a series of essays describing drainage divide areas in and surrounding the Montana Teton River drainage basin. Essays describing specific Teton River drainage divide areas can be found listed under the sidebar Teton River category. The Teton River originates along the east-west continental divide in northern Montana and flows in an east direction onto the Montana plains to join the Missouri River with water eventually reaching the Gulf of Mexico. Topographic map evidence observed throughout the Teton River drainage basin, including high mountain areas in the Teton River headwaters area, suggests the entire Teton River drainage basin was deeply eroded by massive south and southeast-oriented floods. Based on evidence from essays describing many other drainage basins the flood waters are interpreted to have been derived from a rapidly melting thick North American ice sheet located in a deep “hole.” The present day Rocky Mountains in Canada and northern Montana are interpreted to be located along the deep “hole’s” western rim, which was uplifted as immense south and southeast-oriented ice-marginal meltwater floods flowed along it. Headward erosion of deep east- and west-oriented valleys captured the south and southeast-oriented floods in sequence from south to north and carved the east-west continental divide as Rocky Mountain uplift and deep flood water erosion created present day topographic features. North-oriented Teton River tributary valleys were eroded by massive reversals of flood flow on north ends of beheaded south-oriented flood flow channels. Previously unexplained topographic map evidence supporting this interpretation includes numerous north-south oriented through valleys linking east-oriented drainage routes, numerous drainage divides, deep through valleys eroded across the present day continental divide, barbed tributaries, elbows of capture, evidence of flood eroded anastomosing channels, and large incised meanders, among other features. These erosional landforms are significant scientific evidence, which has been ignored to date, and which deserves an explanation.

Introduction

  • Essays describing landform origins in the Montana Teton River drainage basin are summarized in this Teton River drainage basin landform origins overview essay (more detailed individual essays are listed under the sidebar Teton River category). This overview essay is one of what will be more than fifty overview essays describing major Missouri River tributary drainage basin drainage divide areas and/or drainage divide areas adjacent to the Missouri River in those states the Missouri River flows through. Each overview essay is a summary of more detailed essays illustrating and describing detailed drainage divide areas within its specific Missouri River tributary drainage basin. An overview of the entire Missouri River drainage basin area landform origins project can be found at the link at the top of this page.  The research project goal is to use topographic map evidence describe landform origins for all Missouri River drainage basin drainage divide areas both within the Missouri River drainage basin and between the Missouri River drainage basin and all adjacent drainage basins. All interpretations of landform origins made in each of what will be more than 500 individual essays is based completely on topographic map evidence illustrated in the individual essays and overview essays. No effort is being made to introduce evidence from sources other than the topographic maps. At the time this essay is being written essays describing all Missouri River drainage basin drainage divide landform origins in the states of Missouri, Iowa, Minnesota, Kansas, Nebraska, South Dakota, and North Dakota and the Canadian provinces of Saskatchewan and Alberta have been written as well as essays for most Missouri River drainage divide area landform origins in eastern and central Montana and northeast Wyoming. Essays describing landform origins for Missouri River drainage basin drainage divide areas in Colorado, Wyoming (except northeast Wyoming), and western Montana have yet to be written, but are being written as the Missouri River drainage basin landform origins are being systematically described. The Missouri River drainage basin landform origins research project is expected to be completed sometime in late 2012 or early 2013 when all Missouri River drainage basin drainage divide landform origins will have been described.
  • The Missouri River drainage basin landform origins research project is the first known attempt systematically use topographic map evidence to interpret landform origins for a large river drainage basin. Previous to this project selected Missouri River drainage basin landform origins have been interpreted based on other types of evidence and topographic map evidence including drainage divides, through valleys, valley orientations, barbed tributaries, elbows of capture, asymmetric drainage divides, erosional escarpments, anastomosing channel evidence, water gaps, wind gaps, and many similar features have been largely ignored and/or interpreted in a very local context. Introduction of this large mass of previously ignored and/or poorly explained erosional landform evidence is producing a fundamentally different landform origin interpretation than previously published and commonly accepted Missouri River drainage basin landform origin interpretations. The topographic map evidence describes a Missouri River erosional history in which deep valleys eroded headward in sequence along and across immense south and southeast-oriented flood flow and which sometimes triggered massive flood flow reversals. Flood waters are interpreted to have been derived from a rapidly melting thick North American ice sheet, which was located in a deep “hole.” The upper Missouri River drainage basin in Montana and northern Wyoming is interpreted to be a deeply eroded remnant of the deep “hole’s” southwest wall, while high Rocky Mountain ranges along the east-west continental divide in Canada, western Montana, and northern Wyoming are interpreted to have originated as segments of the deep “hole’s”  western and southwest rim. Immense south and southeast-oriented ice-marginal melt water floods are interpreted to have flowed along the deep “hole’s” western and southwest rim at a time when the ice sheet stood high above that rim. In time uplift of the Rocky Mountains (which occurred as flood waters flowed across them), ice sheet melting, and headward erosion of deep valleys from both the east and the west created a situation where the deep “hole” rim was no longer higher in elevation than the ice sheet surface to the east and northeast. Huge south oriented ice-walled valleys were carved into the decaying ice sheet’s surface and large east and northeast-oriented valleys eroded headward from the westernmost of those south oriented ice-walled valleys to erode what is now the upper Missouri River drainage basin in Montana and northern Wyoming, and which was the deep “hole’s” southwest wall. At the same time headward erosion of deep valleys from the west captured south- and southeast-oriented flood waters west of the present day Missouri River basin to create the east-west continental divide, with the continental divide being carved by headward erosion of these deep east- and west-oriented valleys in sequence from south to north.

Montana Teton River drainage basin location map

Figure 1: Montana Teton River drainage basin location map. National Geographic Society map digitally presented using National Geographic Society TOPO software.

 

  • Figure 1 is a location map for the Montana Teton River drainage basin and illustrates a region in north central and northwest Montana. The Canadian border is located along the figure 1 north edge. Glacier National Park is located in the figure 1 northwest corner. The east-west continental divide extends in a south-southeast direction from the figure 1 northwest corner through Logan Pass and Marias Pass (both in Glacier National Park) and then along or near the crest of the Lewis and Clark Range to the figure 1 south edge (just west of Helena). Helena is located just west of the figure 1 south center edge. Missoula is located near the figure 1 southwest corner and is located on northwest-oriented Clark Fork with its water eventually reaching the Pacific Ocean. All figure 1 drainage west of the east-west continental divide eventually reaches the Clark Fork including drainage in the north-oriented Middle Fork Flathead River, South Fork Flathead River, and Swan River, which flows to the south-oriented Flathead River, which is west of the figure 1 map area, but which flows through Flathead Lake (along figure 1 west edge) on its way to join the northwest-oriented Clark Fork (west of figure 1). East of the continental divide all figure 1 drainage routes flow to the Missouri River, which can be seen flowing in a north-northwest direction from the figure 1 south center edge to near Wolf Creek where it turns to flow in a northeast direction through Great Falls, Fort Benton, and Loma. South of Big Sandy the Missouri River turns to flow in a south-southeast direction and then in an east-northeast direction to the figure 1 east edge (slightly north of center). The Teton River is a Missouri River tributary originating along the continental divide between Glacier National Park and the Lewis and Clark Range and joining the Missouri River near Loma. The unlabeled east-oriented Teton River tributary flowing north of Bynum Reservoir is Muddy Creek, which will be discussed and seen in figure 5 below and mentioned in the figure 4 discussion. South of the Teton River drainage basin is the east-oriented Sun River drainage basin, with the Sun River being an east-oriented river originating along the continental divide in the Lewis and Clark Range and joining the Missouri River at Great Falls. North of the Teton River drainage basin is the Marias River drainage basin with the Marias River being formed at the confluence of Cut Bank Creek and the Two Medicine River (south of  Cut Bank, Montana) and flowing in an east-southeast and south direction to join the Teton River and Missouri River near Loma. The Two Medicine River and northeast-oriented Two Medicine River tributaries also originate  along the east-west continental divide and are linked by through valleys with both northwest-oriented Flathead River tributaries and with south-oriented Teton River tributaries and headwaters.
  • Looking at the big picture evidence in figure 1 the entire region was located near or along the deep “hole’s” western rim and was eroded by massive south and southeast melt water floods at a time when the present day mountain ranges did not exist. The south and southeast oriented melt water floods flowed on both sides of the present day continental divide and as shown in figure 2 below (and in the maps illustrated in the individual essays) multiple south and southeast oriented flood flow channels crossed what is now the east-west continental divide. The deep northeast and east-oriented Missouri River valley segments seen in figure 1 eroded headward from a giant south oriented ice-walled and bedrock-floored canyon crossing present day Saskatchewan, North Dakota, and South Dakota, which had been carved into the decaying ice sheet surface (segments of which were later reversed to become north oriented ice-walled and bedrock-floored canyons). Headward erosion of the northeast-oriented Missouri River valley segment beheaded south and southeast-oriented flood flow channels (in sequence from east to west) and flood waters on north ends of those beheaded flood flow channels reversed flow direction to erode what are now north, north-northwest, and northwest oriented Missouri River tributary and headwaters valleys (e.g. unnamed north and northwest-oriented Missouri River tributaries in Great Falls area, the north-northwest oriented Smith River, and the north-northwest oriented Missouri River segment seen in figure 1). At the same time deep east-oriented valleys eroded headward from the newly eroded Missouri River valley to capture the south and southeast-oriented flood flow. These east-oriented valleys eroded headward in sequence with Sun River valley headward erosion being slightly in advance of Teton River valley headward erosion, which was slightly in advance of Marias River (and Marias River tributary) valley headward erosion. At the same time headward erosion of deep west-oriented valleys west of the figure 1 map area beheaded southeast-oriented flood flow on the present day northwest-oriented Clark Fork alignment. Flood waters on the northwest end of the beheaded flood flow channel reversed flow direction to erode the deep northwest-oriented Clark Fork valley, which captured south-oriented flood flow on the south-oriented Flathead River alignment. A deep south-oriented valley then eroded headward along the Flathead River alignment and beheaded southeast- and south-southeast oriented flood flow on the Swan River, South Fork Flathead River, and Middle Fork Flathead River alignments. Flood waters on the north ends of the beheaded flood flow channels reversed flow direction to erode what are today the deep north-northwest oriented Swan River and South Fork Flathead River valleys and the deep northwest-oriented Middle Fork Flathead River valley. Headward erosion of these deep valleys from both east and west carved what is today the east-west continental divide and probably occurred as what are today high mountain ranges were rising and as flood waters were deeply surrounding regions.
  • [Many landforms illustrated in this overview essay were not illustrated in the detailed Teton River drainage divide area essays, but are being illustrated here to provide additional evidence supporting the hypothesis that all erosional landforms in the entire Teton River drainage basin, including the high mountain regions, were eroded by massive south and southeast-oriented melt water floods, which were captured by headward erosion of the deep east-oriented Teton River valley and its tributary valleys.]

Flathead River-Teton River drainage divide at Teton Pass

Figure 2: Flathead River-Teton River drainage divide at Teton Pass. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

  • To illustrate the types of topographic map evidence documenting former south-oriented flood flow channels across the present day east-west continental divide figure 2 is a detailed topographic map showing the Flathead River-Teton River drainage divide area at Teton Pass. The west-oriented stream in sections 28 and 29 is Bowl Creek, which flows to the northwest-oriented Middle Fork Flathead River with water eventually reaching the Pacific Ocean. The north-northwest oriented stream originating in the section 27 northwest corner and flowing to the figure 2 north edge is Trail Creek, which is another Middle Fork Flathead River tributary. Note how Bowl Creek headwaters are just north of a deep north-south oriented through valley (or mountain pass) known as Teton Pass in the section 28 southeast corner and the Trail Creek headwaters are just north of an unnamed north-south oriented through valley (or mountain pass) in the section 27 southwest quadrant. South of these two through valleys are south-oriented headwaters of the east-oriented West Fork Teton River, which flows along the figure 2 southeast quadrant south margin to the figure 2 east edge with water eventually reaching the Gulf of Mexico. These two north-south oriented through valleys are water eroded features and were eroded by south-oriented flood flow channels which once crossed the figure 2 map area and which were captured by headward erosion of the much deeper east-oriented West Fork Teton River valley. South-oriented flood flow into what was then the actively eroding West Fork Teton River valley ended when headward erosion of the still deeper south-oriented Flathead River valley beheaded the diverging southeast-oriented flood flow channels leading to among other places the figure 2 map area and triggered a massive flood flow reversal that eroded the deep Middle Fork Flathead River valley and deep Middle Fork Flathead River tributary valleys, including the Trail Creek and Bowl Creek valleys seen in figure 2. Today it may be difficult to imagine an immense south-oriented melt water flood flowing across the figure 2 map area. However the east-west continental divide and other figure 2 drainage divides are significant erosional landform features and were eroded by water erosion. The two north-south oriented through valleys are also significant erosional landform features and were eroded by adjacent channels prior to headward erosion of the west-oriented Bowl Creek valley. The figure 2 map contour interval is 40 feet and the Teton Pass elevation at the continental divide is between 7240 and 7280 feet while the section 27 through valley elevation at the continental divide is between 7360 and 7400 feet. The mountain peak in section 27 is shown as having an elevation of 8481 feet while a mountain peak in section 33 is shown with an elevation of 8260 feet. These elevations suggest the south-oriented flood flow channel on the Teton Pass alignment may have been 1000 feet or more deep at the time it was beheaded by Bowl Creek valley headward erosion. The section 27 through valley flood flow channel was somewhat shallower, although it may have been more than 800 feet deep at the time it was beheaded and reversed by Trail Creek valley headward erosion. Many similar passes or through valleys cross the east-west continental divide and also other mountain region drainage divides in the Teton River western drainage basin and can be explained in a similar manner.

West Fork Teton River-South Fork Teton River drainage divide area

Figure 3: West Fork Teton River-South Fork Teton River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

  • Figure 3 uses a less detailed topographic map to illustrate the West Fork Teton River-South Fork Teton River drainage divide area south of the figure 2 map area. The continental divide can be seen crossing the figure 3 northwest corner. Southwest-oriented Bowl Creek just barely visible in the northwest corner turns to flow in a northwest direction to the northwest-oriented Middle Fork Flathead River, with water eventually reaching the Pacific Ocean. Teton Pass seen in figure 2 is located just north of the figure 3 north edge. The West Fork Teton River flows in a south-southeast and then east direction from near where the continental divide crosses the figure 3 north edge to south of the figure 3 north center edge where it joins the south-oriented Teton River. The Teton River then flows in a south-southeast, east-northeast, southeast, south-southeast, and east direction to the figure 3 east center edge with water eventually reaching the Missouri River and finally the Gulf of Mexico. Note the two north-oriented tributaries flowing to the east-oriented West Fork Teton River segment. These are Olney Creek and Porcupine Creek. Note how the north-oriented Olney Creek valley is linked by a well-defined north-south oriented through valley with south-oriented Nesbitt Creek, which flows to southwest-oriented Roule Creek, which in turn flows to the south-oriented North Fork Sun River, which flows to the figure 3 south edge (west half). Note also well-defined north-south oriented through valleys linking south-oriented North Fork Sun River tributaries with the Bowl Creek valley north of the continental divide. Going back to Porcupine Creek note how it is linked by a well-defined north-south oriented through valley with east-oriented Waldron Creek, which flows to the Teton River. Note also a north-south oriented through valley linking a south-oriented Teton River valley segment with the east-oriented Waldron Creek valley. South of Waldron Creek and a northeast-oriented Waldron Creek tributary is the east-oriented Middle Fork Teton River. Again note the north-south oriented through valleys linking the Waldron Creek valley (and its northeast-oriented tributary valley) with the Middle Fork Teton River valley. South of the Middle Fork Teton River valley is Lonesome Ridge and then the north-northeast and east oriented South Fork Teton River valley. Again note  the north-south-oriented through valleys eroded across Lonesome Ridge. These many noted north-south oriented through valleys are evidence of what at one time were anastomosing south-oriented flood flow channels moving immense meltwater floods across the figure 3 map area. Headward erosion of the east-oriented Sun River valley (south of the figure 3 map area) captured a major south-oriented flood flow channel along the present day south-oriented North Fork Sun River alignment and the deep Sun River valley eroded headward along that channel. At about the same time the deep east-oriented Teton River and its east-oriented South Fork Teton River valley eroded headward into the figure 3 map area and beheaded south-oriented flood flow channels to the newly eroded Sun River valley (south of figure 3). Flood waters on north ends of the beheaded flood flow channels reversed flow direction to erode north-oriented South Fork Teton River tributary valleys (seen along south edge of the figure 3 southeast quadrant). Headward erosion of the east-oriented Middle Fork Teton River valley then beheaded and reversed south-oriented flood flow channels to the newly eroded South Fork Teton River valley. This process was repeated with headward erosion of the Waldron Creek valley and then with headward erosion of the east-oriented West Fork Teton River valley to produce the valley pattern, drainage divides, and through valleys seen in the figure 3 map area today.

Teton River-Muddy Creek drainage divide area at Ralston Gap

Figure 4: Teton River-Muddy Creek drainage divide at Ralston Gap. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

  • Proceeding east of the mountains onto the Montana plains the topographic map evidence also suggests erosion by massive melt water floods, although in the case of figure 4 the landforms suggest flood waters first moved in a southeast direction and later moved in more of an east direction. Figure 4 uses a reduced size detailed topographic map to illustrate the Teton River-Muddy Creek drainage divide area at Ralston Gap and is east of the figure 3 map area. The Teton River flows in an east and southeast direction from the figure 4 west edge (just south of center) to the figure 4 southeast corner region. Ralston Gap is a large east-northeast oriented through valley north of Eureka Reservoir linking the east-oriented Teton River valley with the east-oriented Muddy Creek valley which is north and east of the figure 4 map area. Note how the erosional residuals between Eureka Reservoir and Ralston Gap and also north of Ralston Gap (along the figure 4 north edge) have been streamlined in northwest-southeast directions especially in their higher elevation regions. This northwest-southeast oriented streamlining occurred while massive southeast-oriented melt water floods flowed across the figure 4 map prior to erosion of the deep Ralston Gap through valley. Muddy Creek (which is not seen in figure 4, but which is seen in figure 5) is an east and east-southeast oriented Teton River tributary north of the Teton River. The east-oriented figure 4 valleys were probably eroded by a massive surge of east-oriented flood flow emerging from what was then a rising mountain region just to the west and which was moving toward what were then the actively eroding and much deeper Teton River and Muddy Creek valley heads (which at first were located east of the figure 4 map area)  The immense surge of east-oriented flood water moving toward the actively eroding Teton River and Muddy Creek valley heads split into several diverging channels near the west end of Eureka Reservoir, with a southern channel eroding the deep southeast-oriented Teton River valley segment seen in the figure 4 southeast quadrant, the middle channel eroding the Eureka Reservoir valley, and the northern channel eroding the Ralston Gap valley. Headward erosion of the deep Teton River valley beheaded flood flow to the Eureka Reservoir and Ralston Gap flood flow channels, although the west-east oriented erosional residual in the figure 4 northwest quadrant suggests east-oriented flood water for a time may have continued to move to and through Ralston Gap north of the present day east-oriented Teton River valley. Perhaps more important than details of the flood water movements is recognition that the figure 4 erosional landforms were eroded first by massive southeast-oriented floods and later by massive east-oriented floods.

Muddy Creek-Teton River drainage divide area showing incised meanders

Figure 5: Muddy Creek-Teton River drainage divide area showing incised meanders. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

  • Figure 5 uses a somewhat reduced size detailed topographic map to illustrate the Teton River-Muddy Creek drainage divide area just west of the Teton River-Muddy Creek confluence. Collins, Montana is the small town located on the railroad in the figure 5 east half. The Teton River meanders in an east-northeast direction from the figure 5 southwest corner to the figure 5 east edge (just south of center) while Muddy Creek meanders in a southeast and east-southeast direction from the figure 5 north edge (west half) to the figure 5 east center edge and joins the Teton River just east of the figure 5 map area. Both the Teton River and Muddy Creek valleys show excellent examples of incised meanders with several abandoned meander bends present especially along the Teton River valley walls. While these incised meanders and abandoned meander bends are not illustrated or discussed in the detailed essays they are illustrated here to demonstrate their presence. Such incised meanders and abandoned meander bends are found at a number of locations throughout the Missouri River basin and elsewhere and probably are evidence of deep valley erosion by intense concentrated flood flow carving a moderately deep valley into specific types of underlying material. There probably are other conditions required as well, although such features are observed in other Missouri River drainage basin regions where concentrated flood flow was carving deep valleys into regions covered by stagnant ice and also and in regions underlain with limestone bedrock, although concentrated flood flow is probably an important factor. The hummocky topography seen between Muddy Creek and the Teton River at first glance might be considered to be a glacial moraine material, which is a possibly. If so the presence of a glacial moraine at this location could mean the Teton River and Muddy Creek valleys were being eroded into a mass of stagnant ice, perhaps a decaying ice sheet remnant. Another possibly however is the hummocky topography is formed by flood deposited debris, probably deposited by slower moving flood waters adjacent to the more concentrated flood flow carving the deep valleys. In either case the hummocky topography is related to conditions that existed at the time the Teton River and Muddy Creek valleys were eroded.
  • This overview essay has provided just a brief introduction to the types of topographic maps evidence illustrated in the much more detailed Teton River drainage divide area essays. The detailed essays focus on specific Teton River drainage divide areas and each essay includes location maps and eight topographic maps along with descriptions and discussions of the erosional landforms seen. Each of the location maps and of the 40 topographic maps shown illustrates evidence similar to the evidence seen in the five maps illustrated in this overview essay. And all of the evidence illustrated can be explained in the context of the massive southeast and south-oriented flood flow hypothesis, although the explanations require immense flood volumes, deep flood erosion, and mountain ranges rising as flood waters flowed across them. To most geologists such an interpretation is probably not only outrageous, but unthinkable. However, the evidence shown on these maps has never been satisfactorily explained in any other way. I invite geologists who want to challenge the interpretations I have provided to provide better explanations for the erosional landforms shown and described in this Teton River drainage basin overview essay and in the detail drainage divide area essays, if such better explanations exist.

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.

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