Origin of North America east-west continental divide, Teton River-Flathead River drainage divide area, Montana, USA

Authors

Abstract:

This essay uses topographic map evidence to interpret landform origins in the Montana Teton River-Flathead River drainage divide area. Today the Teton River originates along the North America’s east-west continental divide and flows in a south-southeast and east direction to join the Missouri River with water eventually reaching the Gulf of Mexico. The northwest-oriented Middle Fork Flathead River, including a major south-oriented tributary, originates just west of Teton River headwaters and flows to the south- and west-oriented Flathead River with water eventually reaching the Pacific Ocean. The North American east-west continental divide segment located along the Teton River-Flathead River drainage divide in Montana’s Lewis and Clark Range is today a region of high mountains and mountain ridges separated by deep valleys, yet multiple north-south oriented through valleys (or mountain passes) cross the continental divide and other major drainage divides and provide evidence of numerous south-oriented flood flow channels which once flowed freely across the Teton River-Flathead River drainage divide region as much deeper valleys from both the east and west to capture the immense south-oriented flood flow and to carve the present day east-west continental divide. Probably the mountains were being uplifted as immense floods moved across the region to these new and deep valleys. Based on hundreds of similar drainage divide area studies flood waters are interpreted to have been derived from a rapidly melting thick North American ice sheet. The decaying ice sheet is interpreted to have been located in a deep “hole” with the Teton River-Flathead River drainage divide area being located along the deep “hole’s” western rim. Huge ice-marginal melt water floods are interpreted to have flowed in south and southeast directions from Canada and across Montana along an erosional surface where the high Lewis and Clark Range is today. In addition to numerous through valleys (or mountain passes) crossing the east-west continental divide and other regional drainage divides evidence used in interpreting this melt water flood capture interpretation includes barbed tributaries, elbows of capture, evidence for diverging and converging flood flow channels, and evidence of dismembered drainage routes.

Preface:

The following interpretation of detailed topographic map evidence is one of a series of essays describing similar evidence for all major drainage divides contained within the Missouri River drainage basin and for all major drainage divides with adjacent drainage basins. The research project is interpreting evidence in the context of a previously unexplored deep glacial erosion paradigm, which is fundamentally different from most commonly accepted North American glacial history interpretations. Project essays available at this site may be found by selecting desired Missouri River tributaries and/or states from this essay’s sidebar category list.

Introduction:

  • The purpose of this essay is to use topographic map interpretation methods to explore the North America east-west continental divide origin in the Teton River-Flathead River drainage divide area of Montana, USA. 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 and/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 providing links to those essays in a comment here.
  • This essay is also exploring a new geomorphology 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 other essays in the Missouri River drainage basin landform origins research project is a thick North American ice sheet, comparable in thickness to the Antarctic ice sheet, occupied the North American region usually recognized to have been glaciated, and through its weight and erosive actions created a deep North American “hole”. The southwestern rim of that deep “hole” is today preserved in the high Rocky Mountains. The ice sheet 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 the North America east-west continental divide origin in the Teton River-Flathead River drainage divide area of Montana will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm (see paradigm related essay listed above this essay’s title). This essay is included in the Missouri River drainage basin landform origins research project essay collection.

Teton River-Flathead River drainage divide area location map

Figure 1: Teton River-Flathead River drainage divide area location map (select and click on maps to enlarge). National Geographic Society map digitally presented using National Geographic Society TOPO software.

 

  • Figure 1 provides a location map for the Teton River-Flathead River drainage divide area in Montana. The Canadian border is located along the figure 1 north edge. The Montana-Idaho border crosses the figure 1 southwest corner. Glacier National Park is the large green area in the figure 1 northwest quadrant. The east-west continental divide extends in a south-southeast direction from the figure 1 north edge through Logan Pass and Marias Pass in Glacier National Park and then along or near the Lewis and Clark Range crest to the figure 1 south edge (west of Helena). The Missouri River flows in a north-northwest direction from the figure 1 south edge (just east of Helena) to Wolf Creek and then turns to flow in a northeast direction to Great Falls, Fort Benton and Loma with water eventually reaching the Mississippi River and the Gulf of Mexico. Major east-oriented Missouri River tributaries with headwaters along the east-west continental divide from south to north are the Dearborn River, the Sun River, the Teton River, and the Marias River. The Marias and Teton Rivers join the Missouri River at Loma while the Sun River joins the Missouri River at Great Falls. The Teton River originates along the continental divide north of Rocky Mtn. and west of Bynum Reservoir (labeled features near figure 1 center). North of the Teton River headwaters are headwaters of northeast-oriented Birch Creek, which is a Marias River tributary, and of northeast-oriented Dupuyer Creek (shown though unlabeled, but is the stream flowing through the town of Dupuyer), which is a Birch Creek tributary. South and southwest of the Teton River headwaters is the Sun River while west of the Teton River headwaters, and west of the continental divide, are headwaters of northwest-oriented Middle Fork Flathead River (with a south-oriented tributary). The Middle Fork Flathead River flows in a northwest direction from the continental divide region to near West Glacier where it joins the north-northwest oriented South Fork Flathead River and south-oriented North Fork Flathead River to form the south-oriented Flathead River, which flows to and through Flathead Lake and then in a south and west direction to the northwest-oriented Clark Fork, with water eventually reaching the Columbia River and Pacific Ocean. This essay illustrates and describes topographic map evidence in the region between the south-southeast oriented Teton River headwaters and the south-oriented Middle Fork Flathead River tributary. Other Teton River drainage divide area essays are listed under the Teton River category (see sidebar category list)
  • The east-west continental divide is a well-known erosional landform, yet its origin has never been well explained and is almost never discussed by the geomorphology research community. This essay uses topographic map evidence in the Montana Teton River-Flathead River drainage divide area to demonstrate the east-west continental divide was eroded by immense south and southeast-oriented floods which initially flowed across a high-level erosion surface, and which were captured by headward erosion of much deeper east- and west-oriented valleys. While this interpretation may appear outrageous based on commonly accepted geology models, this interpretation is based on easy to observe topographic map evidence, which is available to anyone willing to look. Briefly the figure 1 drainage systems evolved during the rapid melt down of a thick North American ice sheet, which was located in a deep “hole.” The deep “hole’s” southwest wall is today the deeply eroded Missouri River drainage basin in Montana and northern Wyoming. Crustal warping, probably related to the ice sheet’s tremendous weight, significantly raised non glaciated regions throughout the North American continent including major mountain ranges and high plateau areas. These mountain ranges and high plateau areas were uplifted as immense south oriented melt water floods flowed across them. Huge south and southeast-oriented ice-marginal meltwater floods from the decaying ice sheet’s western margin in Canada (to the north of figure 1) flowed across the figure 1 map area prior to headward erosion of deep east- and west-valleys used by present day drainage routes. Initially these immense floods flowed on erosion surfaces comparable to elevations of the highest ridges (or even higher) found in the figure 1 mountain ranges today. Headward erosion of deep valleys from both the east and west systematically captured the massive south and southeast-oriented melt water floods as the present day east-west continental divide and other figure 1 drainage divides were carved into what were probably rising mountain masses. While today it may be difficult to imagine huge floods flowing across the region topographic map evidence demonstrates multiple south- and southeast-oriented flood flow channels once were eroded parallel to and adjacent to the present day east-west continental divide, but also crossed the present day continental divide two or more times. Excellent topographic map evidence for such flood flow channels is found in the Teton River-Flathead River drainage divide area and is illustrated and discussed in the following essay.

Detailed location map for Teton River-Flathead River drainage divide area

Figure 2: Detailed location map for Teton River-Flathead River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

  • Figure 2 provides a detailed location map for the Teton River-Flathead River drainage divide area. The continental divide is labeled and extends in roughly a southeast direction from near Elkcalf Mountain in the figure 2 northwest corner to Muskrat Pass and Badger Pass and then to near Mt. Wright. Near Mt. Wright the continental divide makes a west-southwest jog to Kevan Mtn. where it then extends in a south direction to the figure 2 south edge (west half) with a westward jog near Spotted Bear Pass. Not all passes are labeled, the ones that are illustrate the presence of north-south oriented passes cut across what are today east-west oriented continental divide segments. These passes are in reality drainage divides separating north- and south oriented drainage routes on the floors of dismembered flood flow channels. Several such north-south oriented through valleys are illustrated in the topographic maps illustrated below. The North Teton River (not labeled on figure 2) originates just east of Mt. Patrick Gass (just north of Mt. Wright) and flows in a south-southeast direction to join the south- and east-oriented West Fork Teton River (also not labeled, but which originates west of Mt. Wright and which flows in an east direction south of Mt. Wright to join the south-southeast oriented North Fork Teton River). From the confluence of its North and West Forks the Teton River flows in a southeast direction until south of Choteau Mountain it turns to flow in an east and southeast direction to Choteau, Montana (the town in the figure 2 southeast quadrant) and then in a northeast direction to the figure 2 east edge (south half). The Middle Fork Flathead River originates in the region north of the west-southwest oriented jog the continental divide makes in the region between Mt. Wright and Kevan Mtn. The south-oriented stream originating just south of Badger Pass is Strawberry Creek (not labeled) and flows to near Mt. May and then makes a U-turn where it is joined by a northwest-oriented tributary (Bowl Creek-not labeled) and becomes the northwest-oriented Middle Fork Flathead River. The north-northwest oriented and north oriented stream at Badger Pass is Badger Creek, which eventually flows to the Marias River. The northeast-oriented stream originating near Badger Pass is the North Fork Birch Creek with water also eventually reaching the Marias River. South of Mt May Bowl Creek originates north of the south-oriented West Fork Teton River headwaters and flows in a west and southwest direction before turning to flow in a northwest direction to join Strawberry Creek to form the northwest-oriented Middle Fork Flathead River. South of the elbow of capture, where Bowl Creek turns from flowing in a southwest to northwest direction is Sun River Pass, which is not labeled on figure 2. The stream flowing in a south and southeast direction from Sun River Pass is the North Fork Sun River. Unnamed passes link the west-oriented Bowl Creek headwaters with the south- and east-oriented West Fork Teton River headwaters. North of the North Fork Teton River headwaters are headwaters of the north-northwest oriented South Fork Birch Creek, which flows to northeast-oriented Birch Creek and the Marias River. An unnamed pass links the south-oriented North Fork Teton River headwaters with the north-oriented South Fork Birch Creek headwaters. The multiple north-south-oriented passes identified on this location map provide evidence for multiple north-south oriented through valleys, some which are adjacent to the east-west continental divide and some of which cross the continental divide, not once, but twice. These and other passes will be seen in detail on the topographic maps below.

Strawberry Creek-Middle Fork Flathead River drainage divide area

Figure 3: Strawberry Creek-Middle Fork Flathead River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

  • Figure 3 illustrates the Strawberry Creek-Middle Fork Flathead River drainage divide area south and west of the east-west continental divide. The Pondera-Flathead County border can be seen near the figure 3 northwest quadrant north edge and is the east-west continental divide. South of the figure 3 north center area the east-west continental divide defines the Teton-Flathead County border. Drainage in Pondera and Teton Counties eventually reaches the Gulf of Mexico while drainage in Flathead County eventually reaches the Pacific Ocean. Two deep north-south oriented through valleys crossing the continental divide (Pondera-Flathead County border) can be seen just west of the figure 3 north center edge. Beaver Lake is located just south of the western through valley, which is named Muskrat Pass (not labeled in figure 3) and which links the northwest-oriented Muskrat Creek valley (not seen in figure 3) with the southwest, south, and southwest oriented Cox Creek valley, with Cox Creek joining the northwest and west oriented Middle Fork Flathead River near the figure 3 west center edge. North of the figure 3 map area Muskrat Creek joins northeast-oriented Badger Creek, which is a Marias River tributary, with water eventually reaching the Gulf of Mexico. South-oriented Strawberry Creek originates just south of the eastern through valley, which is named Badger Pass (not labeled in figure 3), while northwest oriented South Badger Creek originates just north of Badger Pass. South of Badger Pass Strawberry Creek flows in a south direction (with a minor southwest jog) almost to the figure 3 south center edge and then makes a U-turn to join the north, northwest, and west oriented Middle Fork Flathead River. Bruce Creek originates near the figure 3 southeast corner and flows in a south-southeast direction to the figure 3 south edge (just west of southeast corner). South and east of the figure 3 map area Bruce Creek flows to the south-southeast-oriented North Fork Teton River (see figure 5). Most other drainage routes in the figure 3 Teton County area flow eventually to northeast-oriented Birch Creek, which is a Marias River tributary. Note Gateway Pass crossing the continental divide in the labeled section 31 in the figure 3 southeast quadrant. Gateway Pass links northwest and southwest oriented Gateway Creek with southeast, north-northeast and north-northwest oriented Trail Creek which flows to north-northwest oriented South Fork Birch Creek and then to north-northeast Birch Creek.
  • Our major concern in figure 3 is with Badger Pass, Muskrat Pass, and an additional north-south oriented through valley (or pass) crossing the continental divide west of Muskrat Pass (and which links a north oriented Muskrat Creek tributary valley with the south and southeast oriented Burnt Creek valley, with Burnt Creek being a Cox Creek tributary). Figure 4 provides a detailed topographic map of the Badger Pass region while figure 3 provides a big region map to illustrate relationships of the three passes to the Strawberry Creek U-turn.  Evidence the three passes were eroded during a large south-oriented flood includes the fact three closely spaced north-south oriented and diverging and converging through valleys cross the west to east oriented continental divide segment near the figure 3 northwest quadrant north edge. The three north-south south oriented through valleys are water eroded landforms and were formed when large volumes of south-oriented flood waters were moving across the figure 3 map region. South-oriented Strawberry Creek, Cox Creek, and Burnt Creek valley segments were eroded as south-oriented flood flow channels moving large volumes of flood water from what is today the Marias River drainage basin across the Middle Fork Flathead River headwaters drainage area to the figure 3 south edge and then to the Sun River drainage basin (south of figure 3, but seen in figures 8). These south-oriented flood flow channels diverged in the Badger Creek drainage basin north of the figure 3 map area and then converged in the figure 3 map area and were joined by a major southeast oriented flood flow channel on the present day northwest-oriented Middle Fork Flathead River alignment. Flood flow on that major southeast-oriented flood flow channel was beheaded north and west of the figure 3 map area by headward erosion of the much deeper south-oriented Flathead River valley. Flood waters on the northwest end of the beheaded flood flow channel reversed flow direction to erode the northwest-oriented Middle Fork Flathead River valley and to capture south-oriented flood flow moving in the south-oriented Burnt Creek, Cox Creek, and Strawberry Creek flood flow channels. Headward erosion of the deep northeast-oriented Badger Creek valley north of the figure 3 map area next beheaded south-oriented flood flow to the south-oriented Burnt Creek, Cox Creek, and Strawberry Creek valleys. Flood waters on north and northwest ends of the beheaded flood flow channels reversed flow direction to erode the northwest-oriented South Badger and Muskrat Creek valleys and the northeast-oriented Muskrat Creek tributary valley.

Detailed map of South Badger Creek-Strawberry Creek drainage divide area

Figure 4: Detailed map of South Badger Creek-Strawberry Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

  • Figure 4 provides a detailed topographic map of the South Badger Creek-Strawberry Creek drainage divide area seen in less detail in figure 3. The continental divide is marked and labeled. Badger Pass is near the figure 4 center and is also labeled. South Badger Creek flows in a northwest direction from Badger Pass to the figure 4 north edge (west half) and north of figure 4 flows northeast-oriented Badger Creek which then flows to the Marias River, with water eventually reaching the Mississippi River and Gulf of Mexico. Strawberry Creek originates at Badger Pass and flows in a south-southeast and south-southwest direction to the figure 4 south center edge. South of figure 4 Strawberry Creek flows in a south direction and then makes a U-turn to join the northwest-oriented Middle Fork Flathead River with water eventually reaching the Columbia River and Pacific Ocean. Muskrat Pass can be seen in the figure 4 northwest corner and headwaters of northwest-oriented Muskrat Creek can just barely be seen. Cox Creek originates near Muskrat Pass and flows in a southeast direction to Beaver Lake and then in a south-southwest direction to the figure 4 west edge (south half). Note how a deep west to east oriented through valley (used by the Continental Divide National Scenic Trail) crosses the continental divide and links the Muskrat Pass through valley with the Badger Pass through valley. The figure 4 map contour interval is 40 feet. The floor of the Badger Pass through valley at the continental divide is between 6240 and 6280 feet in elevation. The west-east oriented through valley linking the Muskrat Pass and Badger Pass through valleys has an elevation of between 6400 and 6440 feet at the continental divide. The Muskrat Pass through valley floor elevation is marked as 5974 feet. Family Peak near the figure 4 north edge rises to 8086 feet while Cap Mountain (near figure 4 south edge, west of center) rises to 7612 feet. Most ridges in the figure 4 map area are somewhat lower, but most stand hundreds of feet higher than the three deep through valleys crossing the continental divide. These three deep through valleys provide evidence of what was once a flood eroded anastomosing channel complex with flood waters freely flowing across what is now the east-west continental divide. The west-east oriented through valley is evidence of how a southeast-oriented flood flow split (near present day Beaver Lake) with one diverging channel flowing to what was then the actively eroding Cox Creek valley and the other diverging channel joining an adjacent south- oriented flood flow channel crossing Badger Pass to what was then the south-oriented Strawberry Creek valley. Headward erosion of the much deeper northeast-oriented Badger Creek valley north of the figure 4 map area beheaded the southeast-oriented flood flow channels. Flood waters on northwest ends of beheaded flood flow channels reversed flow direction to erode the northwest-oriented Muskrat Creek and South Badger Creek valleys and also to create the east-west continental divide.

Strawberry Creek-North Fork Teton River drainage divide area

Figure 5: Strawberry Creek-North Fork Teton River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

  • Figure 5 illustrates a big region topographic map of the Strawberry Creek-North Fork Teton River drainage divide area south and slightly west of the figure 3 map area and includes significant overlap areas with figure 3. The east-west continental divide is marked and labeled, serves as the Teton-Flathead County boundary, and extends in a south-southeast direction from the figure 5 north edge (west of center) to the figure 5 south edge (east of center). Strawberry Creek is the south oriented stream west of the continental divide, which in the figure 5 southwest quadrant makes a U-turn to become the northwest-oriented Middle Fork Flathead (which flows to the figure 5 west center edge). As previously described water in the Middle Fork Flathead River eventually reaches the Pacific Ocean. Bowl Creek is the northwest-oriented stream joining south- and west-oriented Strawberry Creek to form the northwest-oriented Middle Fork Flathead River. Note how the south-oriented Strawberry Creek segment is joined by north-northwest oriented Trail Creek and South Fork Trail Creek segments, which are located in the southward extension of the south-oriented Strawberry Creek valley. South of the figure 5 map area the through valley continues across Sun River Pass (across the continental divide) and then becomes the valley of the south-southeast oriented North Fork Sun River. Water in the Sun River eventually reaches the Gulf of Mexico. This large north-south oriented through valley is a former south-oriented flood flow channel and crosses the present day continental at both Badger Pass and at Sun River Pass. South-oriented flood flow to what was then the actively eroding North Fork Sun River valley ended when headward erosion of the deep south-oriented Flathead River valley beheaded southeast-oriented flood flow on the present day northwest-oriented Middle Fork Flathead River alignment. Flood waters on the northwest end of the beheaded flood flow channel reversed flow direction to erode the northwest-oriented Middle Fork Flathead River-Bowl Creek valley and to capture south-oriented flood flow in the Strawberry Creek flood flow channel by beheading south-oriented flood flow to the actively eroding North Fork Sun River valley. Note also how Trail Creek has north-northwest and west-southwest headwaters before entering the large through valley south of south-oriented Strawberry Creek segment. The north-northwest oriented Trail Creek headwaters (west of the figure 5 south center edge area) are linked by a north-south through valley at Teton Pass (along the figure 5 south edge) with south- and east-oriented West Fork Teton River headwaters. Sun River Pass and Teton Pass will be better seen in figures 8, 9, and 10 below.
  • The North Fork Teton River originates near Bloody Hill in the figure 5 east center area and flows in a south-southeast direction to the figure 5 south edge (just west of the southeast corner). South of the figure 5 map area the North Fork Teton River joins the east-oriented West Fork Teton River to form the south-southeast and east oriented Teton River. Bruce Creek is a south-southeast and east oriented tributary north of Mount Wright in the figure 5 southeast quadrant. Nanny Creek is an east-oriented tributary north of the east-oriented Bruce Creek segment. North of the south-southeast oriented North Fork Teton River headwaters valley is the north-northwest oriented Phone Creek headwaters valley with Phone Creek flowing to north-northwest oriented South Birch Creek, which flows to northeast-oriented Birch Creek and then the east-oriented Marias River. North of the south-southeast oriented Bruce Creek headwaters and the east-oriented Nanny Creek headwaters is north-northwest oriented Crazy Creek, which flows to north-northeast and north oriented South Fork Birch Creek which then flows to Birch Creek. Note how the north-northwest oriented Phone Creek headwaters valley is linked by a through valley with the south-southeast oriented North Fork Teton River valley. Also note how the north-northwest Crazy Creek valley is linked by through valleys with the south-southeast oriented Bruce Creek headwaters valley and with the east-oriented Nanny Creek valley. These through valleys will be seen in more detail in figures 6 and 7 below. The Birch Creek-Teton River drainage divide seen in figure 5 east of the continental divide was formed when headward erosion of the deep northeast-oriented Birch Creek valley beheaded south-oriented flood flow channels to the actively eroding Teton River valley and its actively eroding tributary valleys and flood waters on north ends of the beheaded flood flow channels reversed flow direction to erode north-oriented Birch Creek tributary valleys. Also note how the northeast-oriented Trail Creek valley is linked by a north-southeast oriented through valley across the continental divide at Gateway Pass with the northwest-oriented Gateway Creek valley, with Gateway Creek then turning to flow in a southwest direction to south-oriented Strawberry Creek. While more complex than the other passes in origin Gateway Pass provides additional evidence of multiple flood flow channels crossing what is today the east-west continental divide.

Detailed map of Crazy Creek-Nanny Creek drainage divide area

Figure 6: Detailed map of Crazy Creek-Nanny Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

  • Figure 6 provides a detailed map of the Crazy Creek-Nanny Creek drainage divide area seen in less detail in figure 5 above. The east-west continental divide is marked and labeled and serves as the Teton County-Flathead County border. Trail Creek is the north-northwest and west-southwest oriented stream south and west of the continental divide in the figure 6 southwest quadrant and flows to south oriented Strawberry Creek, which then flows to the northwest-oriented Middle Fork Flathead River. South of the figure 6 map area Trail Creek headwaters are located at Teton Pass, which is drained in the south by the south- and east-oriented West Fork Teton River. In the figure 6 northwest quadrant, north of the continental divide, the South Fork Birch Creek originates at Gateway Pass (near northwest corner) and flows for a short distance in a southeast direction before turning to flow in a northeast direction to the figure 6 north edge. My Creek originates in section 5 and flows in a north-northeast and north direction to the figure 6 north edge and joins the South Fork Birch Creek just north of the figure 6 north edge. Note in section 5 how a deep north-south oriented through valley across the continental divide links the north-oriented My Creek valley with the a south-oriented Trail Creek tributary valley and the north-northwest oriented Trail Creek headwaters valley. The figure 6 map contour interval is 40 feet and the through valley floor is more than 1400 feet lower than the high ridges on either side. This through valley was eroded by south-oriented flood flow, which crossed the continental divide at least twice, with the second crossing at Teton Pass south of the figure 6 map area.
  • The North Fork Teton River (labeled Teton River in figure 6) originates in sections 1 and 2 in the figure 6 northeast quadrant and flows in a south-southeast direction to the figure 6 southeast corner. North-northwest oriented Phone Creek originates in section 35 north of the North Fork Teton River headwaters and flows to the figure 6 north edge. Figure 7 below looks at the Phone Creek-North Fork Teton River drainage divide area, which is discussed at that point. Nanny Creek originates in the section 10 southeast quadrant and flows in an east direction to join the south-southeast oriented North Fork Teton River. Bruce Creek originates in the section 10 southwest quadrant and flows in a south-southeast direction to the figure 6 south edge and then in an east direction to join the North Fork Teton River near the figure 6 southeast corner. Crazy Creek originates in the section 10 northwest quadrant and flows in a north-northwest and north direction to the figure 6 north edge and then joins the South Fork Birch Creek. Note how in section 10 a well-defined through valley links the north-northwest oriented Crazy Creek valley with the east-oriented Nanny Creek valley and then with the south-southeast oriented Bruce Creek valley (a trail crosses both through valleys). The Crazy Creek-Nanny Creek through valley at the drainage divide has a floor elevation of between 7600 and 7640 feet while the Nanny Creek-Bruce Creek through valley floor elevation at the drainage divide is between 7520 and 7560 feet. The peak to the west rises to 8279 feet, peaks to the east rise even higher, suggesting the through valleys were originally eroded by a 600 foot or deeper south-oriented flood flow channel. Headward erosion of the deep east-oriented Bruce Creek valley first captured the south-oriented flood flow. Next headward erosion of the east-oriented Nanny Creek valley captured the flood flow and beheaded flood flow channel to what was then the actively eroding Bruce Creek valley. Next headward erosion of the much deeper northeast-oriented Birch Creek valley beheaded the south-oriented flood flow channel and flood waters on the north end of the beheaded flood flow channel reversed flow direction to erode the north-oriented Crazy Creek valley. Yet to be beheaded flood waters from the west may have moved across what is today the high continental divide west of the Crazy Creek headwaters to supply water volumes required to erode the Crazy Creek valley (in other words the figure 6 west half was not deeply eroded until after the Crazy Creek flood flow reversal).

Detailed map of Phone Creek-North Fork Teton River drainage divide area

Figure 7: Detailed map of Phone Creek-North Fork Teton River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

  • Figure 7 provides a detailed topographic map of the Phone Creek-North Fork Teton River through valley and illustrates still another north-south oriented through valley parallel to and adjacent to the east-west continental divide. The North Fork Teton River (labeled Teton River in figure 7) originates in sections 1 and 2 and flows in a south-southeast direction to the figure 7 south edge (just east of center). Phone Creek originates in section 35 and flows in a north-northwest and north-northeast direction to the figure 7 north center edge. North of the figure 7 map area Phone Creek flows to north-oriented South Fork Birch Creek, which then flows to northeast-oriented Birch Creek. A deep through valley in the southwest corner of the section labeled PB 44 links the north-oriented Phone Creek valley with the south-oriented Teton River valley. The figure 7 map contour interval is 40 feet and the through valley floor elevation at the drainage divide is between 6880 and 6920 feet. The ridge to the east rises to more than 8000 feet while Mount Patrick Gass to the west rises to 8620 feet. In other words the Phone Creek-North Fork Teton River valley originated as a south-oriented flood flow channel that may have been as much as 700 feet deep. The south-oriented flood flow was moving to the deep south-southeast and east oriented Teton River valley, which was actively eroding headward into the region. Headward erosion of deep valleys probably was aided by uplift the figure 7 mountain region which occurred as flood waters flowed across the area. Headward erosion of the deeper northeast-oriented Birch Creek valley beheaded the south-oriented flood flow channel. Flood waters on the north end of the beheaded flood flow channel reversed flow direction to erode the north-oriented Phone Creek-South Fork Birch Creek valley.
  • The east-northeast oriented stream flowing to the figure 7 northeast corner is the North Fork Dupuyer Creek. Note how tributaries from the south originate as northwest and north-oriented streams. South Creek is the north-northwest and north oriented tributary originating in the north half of the section marked PB 43. Kid Creek is the north-northwest, west, and southwest oriented North Fork Teton River tributary flowing across the PB 43 area south half. Note a deep through valley linking the north-oriented South Creek valley with the west-oriented Kid Creek valley. This through valley defines still another flood flow channel. Additional through valleys, some at much higher elevations, can be found crossing drainage divides elsewhere in the figure 7 map area. These through valleys are what remain of the converging and diverging south-oriented flood flow channels which were eroded into a high level erosion surface which once existed in the figure 7 map region. Headward erosion of the deep Teton River valley first captured the south-oriented flood flow channels, Next headward erosion of the northeast-oriented Dupuyer Creek valley and its North Fork Dupuyer Creek valley beheaded and reversed flood flow channels to what were then actively eroding Teton River tributary valleys. Finally headward erosion of the deep northeast-oriented Birch Creek valley beheaded and reversed the flood flow channels to create the Birch Creek-Teton River drainage divide seen in figure 7.

Trail Creek-West Fork Teton River drainage divide area

Figure 8: Trail Creek-West Fork Teton River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

  • Figure 8 uses a big region topographic map to illustrate the Trail Creek-West Fork Teton River drainage divide at Teton Pass and adjacent areas. The east-west continental divide is labeled and extends in south, east-southeast, and south-southeast direction from Gateway Pass at the figure 8 north edge (west of center) to Teton Pass near the figure 8 center. From Teton Pass the continental divide extends in a west, south-southwest, and west direction to Sun River Pass in the figure 8 southwest quadrant. From Sun River Pass the continental divide continues in a southwest and west direction to the figure 8 west edge. Strawberry Creek flows in a south and west direction from the figure 8 north edge (east of northwest corner) to the figure 8 west edge (north of center) where it joins northwest-oriented Bowl Creek and becomes the Middle Fork Flathead River. Bowl Creek originates at Teton Pass and flows in a north-northwest, west-southwest, and southwest direction to just north of Sun River Pass and then tuns to flow in a northwest direction to join Strawberry Creek and to form the Middle Fork Flathead River. Trail Creek is the stream with long north-northwest oriented segment originating at Teton Pass and then turns to flow in a west-southwest direction to enter the large Strawberry Creek-Sun River Pass through valley where it turns to flow in a north-northwest direction to join south-oriented Strawberry Creek. South of Sun River Pass is south-oriented Fool Creek, which near the figure 8 south edge joins other streams to form the south-oriented North Fork Sun River. Sun River Pass is a deep north-south oriented through valley across the continental divide and documents how the south-oriented Badger Creek-Strawberry Creek-North Fork Sun River through valley crosses the continental divide a second time, documenting that south-oriented flood waters once flowed along and across the continental divide. As previously described this former flood flow channel was captured by headward erosion of the deep east-oriented Sun River valley and the deep valley knick point then eroded headward along the North Fork Sun River-Fool Creek valley. Headward erosion of the much deeper south-oriented Flathead River valley west and north of the figure 89 map area next beheaded southeast-oriented flood flow to the actively eroding Sun River valley (on the present day northwest-oriented Middle Fork Flathead River-Bowl Creek alignment). Flood waters on the north-west end of the beheaded flood flow channel reversed flow direction to erode the northwest-oriented Bowl Creek-Middle Fork Flathead River valley and to create the continental divide at Sun River Pass. Next Badger Creek headward erosion north of the figure 8 map area captured the south-oriented flood flow and flood waters on the north end of the beheaded flood flow channel reversed flow direction to erode the north-oriented South Badger Creek valley and to create the continental divide at Badger Pass.
  • The North Fork Teton River originates just south of the word “WILDERNESS” seen along the figure 8 north edge (east of center) and flows in a south-southeast direction to join east-oriented Nanny Creek and then east-oriented Bruce Creek before joining the east-oriented West Fork Teton River to form the south-southeast and east-southeast oriented Teton River, which flows to the figure 8 east edge (just north of the figure 8 southeast corner). The West Fork Teton River originates south of Teton Pass and flows in a south-southeast and then east direction to join the south-southeast oriented North Fork Teton River and to form the south-southeast and east-southeast oriented Teton River. Teton Pass is a north-south oriented through valley crossing the continental divide, which was eroded by a south-oriented flood flow channel traceable north of the north-northwest Trail Creek valley segment across the continental divide again to the South Fork Birch Creek valley south of Gateway Pass, where the southeast-oriented flood flow channel that eroded Gateway Pass converged with a south-southwest oriented flood flow channel on the South Fork Birch Creek alignment. After headward erosion of the deep northeast-oriented Birch Creek valley beheaded and reversed south-oriented flood flow channels east of the continental divide, which resulted in erosion of the north-oriented Birch Creek tributary valleys, south-oriented flood flow from west of the continental divide flowed through Gateway Pass and then in a north-northeast direction along the South Fork Birch Creek valley. Headward erosion of the northeast-oriented Badger Creek valley subsequently beheaded all south-oriented flood flow channels to the figure 8 map area and ended erosion of the deep figure 8 valleys. Probably as the deep figure 8 valleys were being eroded the region was also being uplifted, which contributed significantly to headward erosion of the deep valleys and also to development of the high relief found in the figure 8 map area today.

Detailed map of Trail Creek-West Fork Teton River drainage divide area

Figure 9: Detailed map of Trail Creek-West Fork Teton River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

  • Figure 9 provides a detailed topographic map of Trail Creek-West Fork Teton River drainage divide area near Teton Pass, which was seen in less detail in figure 8 above. The east-west continental divide is labeled, serves as the county boundary, and extends from the figure 9 north center edge to the figure 9 south edge (west half). Teton Pass is labeled and is located in the section 28 southeast corner area near the figure 9 center. Teton Pass actually links the west oriented Bowl Creek headwaters valley with the south-southeast and east oriented West Fork Teton River headwaters valley. Just east of Teton Pass in the section 27 southwest quadrant is another unnamed and slightly higher pass across the continental divide which links the north-northwest oriented Trail Creek headwaters valley with the West Fork Teton River valley. Note how in the section 28 northeast quadrant a deeper through valley links the north-northwest oriented Trail Creek valley with the west-oriented Bowl Creek valley. The figure 9 contour interval is 40 feet and this Trail Creek-Bowl Creek through valley floor at the drainage divide has an elevation of between 6920 and 6960 feet. The Teton Pass elevation at the continental divide is between 7280 and 7320 feet. The unnamed pass between Trail Creek and the West Fork Teton River has an elevation at the drainage divide of between 7360 and 7400 feet. The unnamed peak just east of the unnamed eastern pass rises to 8461 feet while a spot elevation of 8260 feet can be seen in section 33 to the southwest of Teton Pass. These elevations suggest Teton Pass and the unnamed pass to the east were eroded by parallel south-oriented flood flow channels (probably eroded into the floor of a much broader south-oriented flood flow channel) that may have been several hundred deep and which were first captured by headward erosion of the much deeper east-oriented West Fork Teton River valley (which has an elevation of less than 6200 where near the figure 9 south edge). Headward erosion of the  somewhat less deep west-oriented Bowl Creek valley next captured the south-oriented flood flow and diverted the flood waters probably to Sun River Pass and what was then the actively eroding North Fork Sun River valley. South-oriented flood flow in the present day Trail Creek valley was captured and diverted to the west. The next event was reversal of southeast-oriented flood flow on the northwest-oriented Middle Fork Flathead River-Bowl Creek alignment, which captured the west- and southwest-oriented Bowl Creek headwaters flood flow to create the west, southwest, and northwest oriented Bowl Creek valley seen today. Headward erosion of the deep west-oriented Trail Creek valley north of the figure 9 map area then beheaded the south-oriented flood flow channel, which caused flood waters on the north end of the beheaded flood flow channel to reverse flow direction and to erode the north-northwest oriented Trail Creek valley.

Detailed map of Bowl Creek-Wrong Creek drainage divide area

Figure 10: Detailed map of Bowl Creek-Wrong Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

  • Figure 10 uses a detailed topographic map to illustrate the Bowl Creek-Wrong Creek drainage divide area west and south of the figure 9 map area and includes overlap areas with figure 9. Teton Pass is located near the figure 10 northeast corner and the continental divide, which is well-marked and labeled, extends from the figure 10 north edge (near Teton Pass) to the figure 10 west edge (just south of center). Bowl Creek flows in a west-southwest, southwest, and northwest direction from the figure 10 north edge (north of Teton Pass) to the figure 10 west edge (north half). Sun River Pass is labeled and is located near the figure 10 west center edge. Fool Creek is the south-oriented stream flowing from near Sun River Pass to the figure 10 south edge along the Lewis and Clark County-Teton County border (both counties are in the Missouri River or Gulf of Mexico drainage basin while Flathead County north of the Sun River Pass and north of the continental divide is in the Flathead River or Pacific Ocean drainage basin). McDonald Creek is the south and south-southwest oriented stream originating between Porphyry Reef and Wrong Ridge south of the continental and east of Fool Creek. South of figure 10 McDonald Creek joins Fool Creek to form the south-oriented North Fork Sun River. Note how three north-south oriented through valleys are located along the continental divide between Porphyry Reef and Wrong Ridge in sections 6 and 5. These through valleys link north- and northwest-oriented Bowl Creek tributary valleys with south-oriented McDonald Creek tributary valleys. The through valleys were eroded as south-oriented oriented flood flow channels prior to headward erosion of the deep Bowl Creek valley when south-oriented flood flow from north of the figure 10 map area was freely flowing across the present day continental divide. East of Wrong Ridge and south of the continental divide are headwaters of south-oriented Wrong Creek which south of the figure 10 map area flows to the south-oriented North Fork Sun River. Note how near the section 5 east edge there is a north-south oriented through valley linking the south-oriented Wrong Creek valley with a north-northwest oriented Bowl Creek tributary valley. This through valley provides evidence of an additional south-oriented flood flow channel. Further east is Washboard Reef and then the east-oriented West Fork Teton River valley head. The multiple north-south oriented through valleys (or mountain passes) crossing the continental divide between (and including) Teton Pass and Sun River Pass provide strong evidence that an anastomosing complex of diverging and converging flood flow channels once crossed the present day continental divide (in 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.

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