Two Medicine River-Birch Creek drainage divide area landform origins near continental divide in Glacier, Pondera, and Teton Counties, Montana, USA

Authors

Abstract:

Topographic map interpretation methods are used to determine Two Medicine River-Birch Creek drainage divide area landform origins near the continental divide in Glacier, Pondrea, and Teton Counties, Montana. The Two Medicine River originates along the continental divide in southeast Glacier National Park and flows in an east direction to join Cut Bank Creek and to form the east and south oriented Marias River, which flows to the Missouri River. Birch Creek originates as north-oriented tributaries and then flows in a northeast direction to join the Two Medicine River near its confluence with Cut Bank Creek. Between the Two Medicine River and Birch Creek is Badger Creek, which also originates along the continental divide in the as north-oriented tributaries, and which flows in a northeast and east direction to join the Two Medicine River. North-oriented Two Medicine River, Badger Creek, and Birch Creek tributary valleys are linked by deep through valleys (or mountain passes) with south oriented tributaries to the north-northwest oriented Middle Fork Flathead River on the opposite side of the continental divide. The deep through valleys and numerous other less deep through valleys (or mountain passes) crossing the continental divide provide evidence of former south-oriented anastomosing flood flow channels, which once crossed the entire region. Flood waters were derived from a rapidly melting thick North American ice sheet (which was located in a deep “hole”) and were flowing in a south and southeast direction along the western and southwestern rim of the deep “hole” being created by the thick ice sheet. The Canadian and Montana Rocky Mountains, or deep “hole’s” western and southwestern rim, were uplifted as gigantic south- and southeast-oriented melt water floods flowed across them. Rocky Mountain uplift (from south to north) and headward erosion of deep valleys from east and west (also from south to north) systematically captured, beheaded and reversed, and/or otherwise dismembered the numerous diverging and converging south-oriented anastomosing flood flow channels to create the valley pattern seen today.

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 Two Medicine River-Birch Creek drainage divide area landform origins near the continental divide in Glacier, Pondera, and Teton Counties, 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 by leaving a link 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 Two Medicine River-Birch Creek drainage divide area landform evidence near the continental in Glacier, Pondera, and Teton Counties, Montana will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm (see link to paradigm related essay in menu at top of page). This essay is included in the Missouri River drainage basin landform origins research project essay collection.

Two Medicine River-Birch Creek drainage divide area location map

Figure 1: Two Medicine River-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 location map for the Two Medicine River-Birch Creek drainage divide area. The west to east boundary line is the Canada-United States border with Montana south of the border and British Columbia in the northwest corner and Alberta being east of British Columbia. Glacier National Park is located south of the border while Waterton Lakes National Park is directly to the north in Canada. The west to east continental divide follows the British Columbia-Alberta border and then extends in a south-southeast direction to the figure 1 south center edge. The north-northwest oriented South Fork Flathead River and northwest-oriented Middle Fork Flathead River are tributaries to the south-oriented Flathead River (which flows through Flathead Lake) to the figure 1 south edge (east half) with water eventually reaching the Pacific Ocean. East of the continental divide most drainage routes are Missouri River tributaries, with the Missouri River being seen in the figure 1 southeast corner flowing in a northeast direction through Great Falls, Fort Benton, and Loma. Missouri River water eventually reaches the Gulf of Mexico. Major east-oriented Missouri River tributaries seen in figure 1 (from south to north) are the Sun River, Teton River, Marias River, and Milk River (which flows into and across southern Alberta before turning to flow back into Montana and to join the Missouri River). Water east of the continental divide and north and west of the Milk River (e.g. the St Mary River, which flows from the Glacier National Park northeast corner to the Lethbridge, Alberta area where it joins the Oldman River) eventually reaches Hudson Bay, meaning there is a triple continental divide in the Glacier National Park northeast corner area. The Marias River is formed at the confluence of east and south-southeast oriented Cut Bank Creek and the east-oriented Two Medicine River, both of which originate along the continental divide in Glacier National Park. Badger Creek and Birch Creek are northeast-oriented Two Medicine River tributaries originating along the continental south of Glacier National Park, with Birch Creek being located south of Badger Creek. The Two Medicine River-Birch Creek drainage divide area investigated in this essay is located in the mountain region near the continental divide and includes Marias Pass and extends southward to the Birch Creek headwaters area. The Cut Bank Creek-Two Medicine River drainage divide area landform origins, Glacier County, Montana essay describes the region directly to the north. The Two Medicine River-Birch Creek drainage divide landform origins east of the mountains, Glacier and Pondera Counties, Montana essay describes the region to the east (Marias River drainage basin drainage divide area essays can be found by selecting Marias River from the sidebar category list).
  • The Two Medicine River-Birch Creek drainage divide area near the continental divide (and elsewhere) was eroded by immense southeast and south oriented melt water floods derived from a rapidly melting thick North American ice sheet, which had been located in a deep “hole.” The deep “hole” developed after the ice sheet formed and was created by a combination of deep glacial erosion and of crustal warping caused by the ice sheet’s great weight. At the time the ice sheet originally formed the Rocky Mountains did not stand high above surrounding regions as they do today. Instead the ice sheet stood high above surrounding regions and huge ice-marginal melt water floods could flow in southeast and south directions along what are today crests of high Rocky Mountain ranges from Canada into Montana, Wyoming, Colorado, and even New Mexico. Uplift of the Rocky Mountains occurred in sequence from south to north as these gigantic melt water floods were flowing on routes corresponding closely with the present east-west continental divide. While fundamentally different from all previously published interpretations evidence presented in this essay demonstrates massive south and southeast oriented floods deeply eroded the present day continental divide region south of Glacier National Park and flood waters were captured by headward erosion of deep valleys from both the east and west to create the present day continental divide. The evidence is in the form of deep through valleys which cross the continental divide, valley orientations, and in the drainage divides that exist today. These landform features exist, are easily identified on topographic maps, and were formed by something and their origins have never been satisfactorily explained. While gigantic volumes of water, far greater than anything considered in previous geological publications, are needed to explain these landforms the landforms can be explained by the rapid melt down of a thick North American ice sheet, which was opening up space in a deep “hole” at the same time as the Rocky Mountains and other North American high areas were being uplifted.
  • Today the upper Missouri River drainage basin in Montana and northern Wyoming (plus the Saskatchewan River drainage basin in western Alberta) represents what remains of the deep “hole’s” deeply eroded southwest wall. How did the upper Missouri River drainage basin develop with its north, northeast, and east oriented valleys? As already noted initially the Rocky Mountains were not high and the ice sheet stood high above the surrounding continental surface. However, as the ice sheet existed and began to melt Rocky Mountain uplift gradually occurred (in sequence from south to north) and at the same time the ice sheet surface elevation gradually became lower. Eventually a point was reached where the rising Rocky Mountains (south and west of the ice sheet southwest margin) were higher than the ice sheet surface to the north and east. Because Rocky Mountain uplift progressed from the southeast to the northwest immense ice-marginal melt water floods flowed in south and southeast directions along what is today the deep “hole’s” west and southwest rim (today the east-west continental divide in Canada and Montana) until the flood waters were blocked by rising Rocky Mountains and plateaus in Wyoming. The gigantic melt water floods were then diverted in north, northeast, and east directions toward space in the deep “hole” being opened up as the ice sheet melted. Space was being opened up in the deep “hole” as huge south oriented supra glacial melt water rivers carved gigantic ice-walled canyons into the decaying ice sheet’s surface. Of particular importance to the Missouri River drainage basin was an immense southeast and south oriented ice-walled canyon in what is today Saskatchewan, North Dakota, and South Dakota, which eventually became an ice-walled and bedrock-floored canyon and which detached the ice sheet’s southwest margin. Today the Missouri Escarpment in Saskatchewan, North Dakota, and South Dakota is what remains of this giant ice-walled and bedrock-floored canyon’s southwest and west wall. This huge ice-walled canyon in time became the primary regional drainage route and deep east- and northeast-oriented valleys eroded headward from it into what is now Montana and northern Wyoming. These valleys eroded headward in sequence from the southeast to the northwest and captured the south and southeast oriented flood flow, which had been moving along what is today the crest of the Rocky Mountains. These captures as already mentioned were greatly aided by Rocky Mountain uplift, which was occurring as the immense melt water floods flowed across them. Headward erosion of the east-oriented Missouri River tributaries seen in figure 1 represented the last of the deep Missouri River tributary valleys to capture the south- and southeast-oriented ice-marginal flood flow, although headward erosion of the deep Saskatchewan River valley and its tributary valleys subsequently captured the south and southeast oriented flood flow further to the north and west.

Detailed location map for Two Medicine River-Birch Creek drainage divide area

Figure 2: Detailed location map for Two Medicine River-Birch Creek 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 Two Medicine River-Birch Creek drainage divide area near the continental divide. County boundaries are shown and county names are given. South of Glacier County is Pondera County and south of Pondera County is Teton County. The east-west continental divide defines the Glacier, Pondera, and Teton County western border. Flathead County is the county west of the continental divide. East Glacier Park is a small town located near the figure 2 center. The Two Medicine River originates west of East Glacier Park along the continental divide and then flows in roughly an east direction to join Cut Bank Creek (south and slightly east of the town of Cut Bank) to form the east-southeast oriented Marias River, which flows to the figure 2 east center edge with water eventually reaching the Gulf of Mexico. Note the South Fork Two Medicine River, which flows in a northwest and northeast direction to join the Two Medicine River just south of East Glacier Park. A northeast oriented tributary flows from Marias Pass to join the northeast oriented South Fork Two Medicine River segment while a southwest oriented tributary flows from Marias Pass to join the northwest and west oriented Middle Fork Flathead River, which then joins the south-oriented Flathead River, which flows to Flathead Lake (in figure 2 southwest corner) with water eventually reaching the Pacific Ocean. South of the South Fork Two Medicine River is northeast- and east-oriented Badger Creek, which originates near Big Lodge Mountain and which is a Two Medicine River tributary. Note how north-oriented Badger Creek headwaters are north of a west to east oriented continental divide segment which is crossed by Muskrat Pass and Badger Pass with south-oriented Middle Fork Flathead River tributaries to the south of those passes. The passes and the valley orientations are important and will be much better seen in the topographic maps illustrated below. The North Fork Birch Creek originates near Badger Pass and flows in an east-northeast direction to join the northeast- and north-oriented South Fork Birch Creek and then to flow in roughly a northeast direction to join the Two Medicine River just before it joins Cut Bank Creek. Continue in a southeast direction from Badger Pass along the continental divide to Gateway Pass and then a bit south and east to the headwaters of the South Fork Birch Creek. Note also the northwest and north-northwest oriented Middle Fork Flathead River west of the continental divide and the south-oriented tributaries to that north-oriented river (which turns near the figure 2 west edge to flow in a south direction). The elbows of captures are better seen on topographic maps, but are evidence of massive flood flow capture events, which resulted in immense flood flow reversals.

Two Medicine River-South Fork Two Medicine River drainage divide area

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

 

 

  • Figure 3 illustrates the Two Medicine River-South Fork Two Medicine River drainage divide area south of East Glacier Park, Montana. The small town of East Glacier Park is near the figure 3 north center edge and the Two Medicine River flows in a southeast and east direction from the figure 3 north center edge to the figure 3 east edge (north half). Summit is the name for the location where the highway and railroad cross the east-west continental divide near the figure 3 southwest corner. On figure 2 the pass is labeled Theodore Roosevelt Pass, although on other maps the pass is named Marias Pass. The South Fork Two Medicine River flows in a northwest direction from the figure 3 south center edge towards Summit Mountain (north of Summit) and then makes an abrupt turn to flow in a northeast and east-northeast direction to join the Two Medicine River in the figure 3 northeast quadrant. The northeast-oriented South Fork Two Medicine River is joined by northeast-oriented Summit Creek just south of the place named False Summit, which is between Summit and East Glacier Park. Note how the South Fork Two Medicine River flows around the west end of Two Medicine Ridge. The figure 3 contour interval is 50 meters and the elevation at Marias Pass appears to be between 1550 and 1600 meters. Little Dog Mountain to the north rises to more than 2600 meters and elevations greater than 2250 meters can be found where the continental divide crosses the figure 3 south edge. Marias Pass is at least 650 meters deep and is a major water eroded valley crossing the present day continental divide. What and how was the Marias Pass valley eroded? And why does the South Fork Two Medicine River flow in a northwest direction to reach what is otherwise an east-oriented drainage system? To answer these questions we need to visualize the figure 3 map area at a time when the mountains did not stand high as they do today, but instead as an area being eroded by immense south-oriented ice-marginal melt water floods. At that time Rocky Mountain uplift was beginning and flood waters were eroding an immense complex of south-oriented anastomosing channels into the rising mountain mass. A major south-oriented flood flow channel entered the figure 3 map area in the East Glacier Park region and diverged into two major channels, with one of the diverging channels moving flood waters eastward while the other diverging flood flow channel moved flood waters in a southwest direction toward Marias Pass. Before reaching   Marias Pass the southwest-oriented channel diverged again with one channel moving flood water in a southeast direction along what is today the northwest-oriented South Fork Two Medicine River valley while the other diverging flood flow channel moved water in a southwest direction to converge with a major south-southeast oriented flood flow channel on the alignment of the present day north-northwest oriented Middle Fork Flathead River. There were additional diverging and converging flood flow channels, I have only identified the major channels to point out how the south and south-southeast oriented flood flow channels diverged and converged as they crossed what is today the east-west continental divide. In time headward erosion of the deep east-oriented Two Medicine River valley and the northeast-oriented South Fork Two Medicine River valley segment beheaded the southeast-oriented flood flow channel on the present day northwest-oriented South Fork Two Medicine River valley segment. Flood waters on the northwest end of the beheaded flood flow channel reversed flow direction to erode the northwest-oriented South Fork Two Medicine River valley segment (erosion was aided by continuing Rocky Mountain uplift). Headward erosion of the west-oriented Middle Fork Flathead River valley segment (west of figure 3) beheaded and reversed south-southeast-oriented flood flow to erode the north-northwest oriented Middle Fork Flathead River valley segment.

South Fork Two Medicine River-Badger Creek drainage divide area

Figure 4: South Fork Two Medicine River-Badger Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

 

  • Figure 4 illustrates the South Fork Two Medicine River-Badger Creek drainage divide area located south of the figure 3 map area and includes overlap areas with figure 3. The east-west continental divide is shown with a dashed line and extends in a southeast and south direction from the figure 4 west edge (north of center) to the figure 4 south edge (west half). The South Fork Two Medicine River flows in a northwest direction across the figure 4 center toward the figure 4 northwest corner and then turns to flow in a northeast direction to the figure 4 north edge (near northwest corner). North Badger Creek flows in a north-northeast direction from the figure 4 south center edge to the South Fork Two Medicine River headwaters area and then turns to flow in a southeast direction to join north-oriented South Badger Creek and to form northeast and north-northeast oriented Badger Creek. Note how Badger Creek is joined several north-northwest oriented tributaries in the figure 4 southeast corner region. North and east of figure 4 Badger Creek joins the Two Medicine River. Note the well-defined through valley linking the northwest-oriented South Fork Two Medicine River valley with the southeast-oriented North Badger Creek valley. The figure 4 map contour interval is 50 meters and at the drainage divide the through valley floor elevation is between 1700 and 1750 meters. Goat Mountain to the south rises to 2496 meters while Half Dome Crag to the north rises to at least 2400 meters. In other words the through valley is almost 700 meters deep. This through valley is a water eroded feature and was eroded by a southeast-oriented flood flow channel as the surrounding mountains were being uplifted. The north-northeast oriented North Badger Creek valley and valleys of the north- and north-northeast oriented Badger Creek tributaries (in the figure 4 southeast corner area) were initiated as diverging south-oriented flood flow channels in what was at that time an immense south and south-southeast oriented anastomosing channel complex, which was being eroded into a region much larger than the figure 4 map area. Headward erosion of the deep northeast-oriented Badger Creek valley (north and east of figure 4) beheaded south-oriented flood flow moving on the present day north-northeast oriented Badger Creek valley alignment. Flood waters on the north end of the beheaded flood flow channel reversed flow direction to erode the north-northeast oriented Badger Creek valley segment and probably the various north-oriented Badger Creek tributary valleys as well, although southeast-oriented flood flow continued to move along the present day northwest-oriented South Fork Two Medicine River valley alignment. Headward erosion of the northeast-oriented South Fork Two Medicine River valley segment (seen in figure 3) then beheaded the southeast-oriented flood flow and flood waters on the northwest end of the beheaded flood flow channel reversed flow direction to erode the northwest-oriented South Fork Two Medicine River valley segment and to create the South Fork Two Medicine River-North Badger Creek drainage divide as seen in figure 4.

Detailed map of South Fork Two Medicine River-North Fork Badger Creek drainage divide area

Figure 5: Detailed map of South Fork Two Medicine River-North Fork Badger Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

 

  • Figure 5 provides a detailed topographic map of the South Fork Two Medicine River-North Fork Badger Creek drainage divide area seen in less detail in figure 4 above. The South Fork Two Medicine River flows in a northwest direction from section 16 to the figure 5 west edge (near northwest corner). North Badger Creek flows in a north-northeast direction in section 27 (near figure 5 south edge) into section 23 where it turns to flow in a southeast direction to the figure 5 east edge (near southeast corner). Note how the Continental Divide Scenic Trail follows the northwest-southeast oriented through valley linking the northwest-oriented South Fork Two Medicine River valley with the southeast-oriented North Badger Creek valley. The figure 5 map contour interval is 40 feet and the through valley floor elevation at the drainage divide is between 5720 and 5760 feet. Elevations in section 10 to the north rise to 7452 feet and in section 29 in the figure 5 southwest quadrant rise to 6897 feet. Based just on figure 5 evidence the through valley is at least 1100 feet deep, however by looking beyond the figure 5 map area much higher elevations can be found both north and south of the figure 5 map area suggesting the through valley may be as much as 2000 feet deep. The through valley is definitely a water eroded feature and it exists, which means it is a landscape feature demanding an explanation. As previously described the through valley was eroded as one of many southeast-oriented flood flow channels in what was a gigantic south-southeast oriented anastomosing channel complex. Flood waters responsible for eroding the south-southeast oriented anastomosing channel complex were flowing along the western and southwest rim of the deep “hole” in which a rapidly melting thick North American ice sheet was located. At the time the anastomosing channels were initiated the Rocky Mountains, which dominate the continental divide area today, did not stand high as they do today. Instead flood waters were able to flow freely in a south and southeast directions across what are today high mountain ranges. Uplift of the mountain ranges occurred as flood waters flowed across them and proceeded from south to north. Uplift in the south combined with headward erosion of deep east and west oriented valleys (in sequence from south to north) systematically beheaded and reversed the south-oriented flood flow channels to erode north- and northwest-oriented valleys such as the northwest-oriented South Fork Two Medicine River valley and to create drainage divides such as the South Fork Two Medicine River-North Badger Creek drainage divide seen in figure 5.

Summit Creek-Bear Creek drainage divide area at Marias Pass

Figure 6: Summit Creek-Bear Creek drainage divide area at Marias Pass. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

 

  • Figure 6 illustrates the Summit Creek-Bear Creek drainage divide area south and west of the figure 3 map area, west and north of the figure 4 map area, and includes overlap areas with figures 3 and 4. The South Fork Two Medicine River flows in a northwest direction from the figure 6 east edge (south of center) around the Two Medicine Ridge west end and then in a northeast and east-northeast direction to the figure 6 northeast corner. Water in the South Fork Two Medicine River eventually reaches the Gulf of Mexico. Summit Creek originates as a south-oriented stream on Little Dog Mountain (north and west of Summit) and makes a  sharp turn to flow in a northeast direction to join the South Fork Two Medicine River south of False Summit (near figure 6 north edge). Bear Creek originates as a southwest-oriented stream on Little Dog Mountain and then makes a U-turn to flow in a northeast direction toward Summit Creek before making another U-turn to flow in a southwest direction to the figure 6 southwest corner area and then to join the north-northwest oriented Middle Fork Flathead River. Water in the Flathead River eventually reaches the Pacific Ocean. The through valley linking the northeast-oriented Summit Creek valley and the southwest-oriented Bear Creek valley is labeled as Theodore Roosevelt Pass (also known as Marias Pass) and has already been described as being at least 650 meters deep. This through valley is a water eroded feature and was eroded as a southwest-oriented flood flow channel diverging from south and south-southeast oriented flood flow channels east of the Rocky Mountain front. The southwest-oriented melt water flood flow was moving to what at that time was a south-southeast flood flow channel on the alignment of the present day north-northwest oriented Middle Fork Flathead River valley segment (see figures 1 and 2). North and west of the southwest-oriented Bear Creek valley (and in a separate southwest-oriented valley) is southwest-oriented Ole Creek, which also flows to the north-northwest-oriented Middle Fork Flathead River. Note how a deep northwest-southeast oriented through valley links the Ole Creek valley with the Bear Creek valley. The figure 6 map contour interval is 50 meters and the through valley floor elevation at the drainage divide is between 1450 and 1500 meters. Elevations on Elk Mountain to the east rise to more than 2350 meters while Running Rabbit Mountain (on the figure 6 east edge) reaches an elevation of 2339 meters. In other words the through valley is more than 800 meters deep and was eroded as a diverging and converging southeast-oriented flood flow channel in the much larger anastomosing channel complex. Headward erosion of the deep west-oriented Middle Fork Flathead River valley segment beheaded and reversed the south-southeast flood flow channel west of the figure 6 map area to erode the north-northwest oriented Middle Fork Flathead River valley segment.

Detailed map of Summit Creek-Bear Creek drainage divide area at Marias Pass

Figure 7: Detailed map of Summit Creek-Bear Creek drainage divide area at Marias Pass. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

  • Figure 7 provides a detailed topographic map of the Summit Creek-Bear Creek drainage divide area at Marias Pass which was seen in less detail in figures 6 and 3. Marias Pass is located near the cluster of buildings labeled as Summit near the figure 7 center. Summit Creek flows in a southeast direction in section 25 (north of Summit) and then turns to flow in an east and then northeast direction along the highway and railroad to the figure 7 north edge (east half). Bear Creek originates as a south and southwest oriented stream in section 26 and makes a U-turn to flow in an east direction across section 35 before turning again in sections 36 and 1 to flow in a south, southwest, and west direction to the figure 7 southwest corner area. The figure 7 map contour interval is 40 feet and the Marias Pass elevation at the Continental Divide is between 5220 and 5240 feet. Little Dog Mountain near the figure 7 north edge rises to 8910 feet while Elkcalf Mountain (just south of figure 7 on the Continental Divide) rises to 7607 feet and elevations greater than 8000 feet can be found by going further south. Note how the Marias Pass through valley is actually a series of through valleys with varying elevations. For example the southwest-oriented Bear Creek valley segment (in section 26) is linked by a through valley with a southwest-oriented stream flowing to the figure 7 west center edge in section 34. That southwest-oriented stream west of figure 7 turns to flow in a south direction to join Bear Creek. The east-west oriented through valley in section 34 has been eroded north of the Blacktail Hills and has an elevation at the drainage divide of between 5480 and 5520 feet. Elevations in the Blacktail Hills rise to 6092 feet in section 2 and the ridge to the north of the through valley is much higher. In other words this secondary through valley is approximately 600 feet deep and provides evidence of what were once multiple west and southwest oriented flood flow channels being eroded across what was probably the rising mountain mass. Some of the figure 7 map evidence such as the small lakes suggests the region may have been glaciated by alpine glaciers. If so the alpine glaciation occurred after the deep Marias Pass valley was eroded and the immense southwest-oriented melt water floods ceased to flow across the figure 7 map area.
  • Why would there be alpine glaciation after the thick North American ice sheet rapid melt down had ended? Remember the figure 1 discussion about giant south-oriented ice-walled and bedrock-floored valleys being carved into the decaying thick ice sheet’s surface. These giant canyons were carved by immense south-oriented melt water rivers, many of which were flowing to what is now the Mississippi River drainage basin with the water eventually reaching the Gulf of Mexico. These immense floods flowing into the Gulf of Mexico pushed warm Gulf of Mexico water into the Atlantic Ocean, where ocean currents then moved the warm water northward to warm the northern hemisphere climate. Warming of the northern hemisphere climate in turn increased the rate of ice sheet melting, which in turn led to even more northern hemisphere warming. However, as the ice sheet decayed and the deep ice-walled canyons became bedrock-floored canyons other north-oriented ice-walled and bedrock-floored canyons began to be carved in the ice sheet surface and in time these north-oriented canyons, which had much shorter routes to the ocean, intersected the south-oriented ice-walled and bedrock-floored canyons and captured the south-oriented melt water floods, which then diverted the flood waters to the North Atlantic Ocean. This diversion of the immense south-oriented melt water floods from the Gulf of Mexico to the North Atlantic Ocean completely changed the direction of the ocean currents. Instead of warm water moving north cold water began to move south. The rapid warming of the northern hemisphere ceased and instead the northern hemisphere cooled significantly. This northern hemisphere cooling caused the gigantic north-oriented melt water floods to freeze on the former thick ice sheet floor, which created a thin wet based ice sheet with remnants of the former thick ice sheet embedded within it. At the same time the climatic change combined with the uplift of the now deeply eroded Rocky Mountains created conditions where alpine glaciers could form in what had become high mountain regions. The thin ice sheet gradually melted without massive melt water floods of the type the thick ice sheet had produced. Many of the alpine glaciers have since melted, although some still remain in the high mountain regions.

South Badger Creek-Strawberry Creek drainage divide area

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

 

 

  • Figure 8 illustrates the South Badger Creek-Strawberry Creek drainage divide area south and east of the figure 4 map area. The Pondera County-Flathead County and Teton County-Flathead County borders are defined by the east-west continental divide and are clearly shown. Pondera, Teton, and Flathead Counties have a common corner near the figure 8 center. The northwest and north oriented stream originating near that common county corner and flowing to the figure 8 north edge (west half) is South Badger Creek. North Badger Creek can just barely be seen flowing in a north-northeast direction across the figure 8 northwest corner. As seen in earlier figures South Badger Creek joins North Badger Creek to form north-northeast and northeast oriented Badger Creek, which then joins the Two Medicine River with water eventually reaching the Gulf of Mexico. The south-oriented stream originating near the figure 8 center and flowing to the figure 8 south center edge is Strawberry Creek. South of figure 8 Strawberry Creek turns to flow in a west direction to join the north-northwest oriented Middle Fork Flathead River with water eventually reaching the Pacific Ocean. Note how the northwest-oriented South Badger Creek valley is linked by a through valley with the south-oriented Strawberry Creek valley. While not labeled on figure 8 the through valley is known as Badger Pass. The figure 8 map contour interval is 50 meters and the Badger Pass elevation at the drainage divide appears to be between 1900 and 1950 meters. Elevations to the west rise to more than 2250 meters and are much higher to the east. In other words this through valley is at least 300 meters deep. Just west of Badger Pass is another deep through valley linking the northwest-oriented Muskrat Creek valley with the southwest and south oriented Cox Creek valley (this unlabeled through valley is known as Muskrat Pass). Muskrat Creek flows to northeast-oriented Elbow Creek, which is a South Badger Creek tributary. Cox Creek is a Middle Fork Flathead River tributary. The elevation of Muskrat Pass at the continental divide appears to be between 1800 and 1850 meters and is lower than Badger Pass. Also note the through valley linking the Muskrat Pass through valley with the Badger Pass through valley, which has an elevation at the drainage divide of between 1900 and 1950 meters. These through valleys are just a few of the deeper through valleys seen in figure 8 which document former south-oriented diverging and converging flood flow channels which once crossed the figure 8 map area. Headward erosion of the west-oriented Middle Fork Flathead River valley (north and west of figure 8) beheaded and reversed south-southeast oriented flood flow on the present day north-northwest oriented Middle Fork Flathead River alignment and in doing so captured flood flow from the south-oriented Cox Creek and Strawberry Creek flood flow channels. Headward erosion of the northeast-oriented Badger Creek valley north and east of figure 8 beheaded and reversed south-oriented flood flow on the South Badger Creek alignment to erode the north-oriented South Badger Creek valley and tributary valleys.

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

Figure 9: 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 9 provides a detailed topographic map of the South Badger Creek-Strawberry Creek drainage divide area seen in less detail in figure 8 above. The Continental Divide is clearly labeled and serves as the county border with Flathead County being west of the drainage divide. Muskrat Pass is located in the figure 9 northwest quadrant and links the northwest-oriented Muskrat Creek valley with the south and southwest oriented Cox Creek valley. Water in Muskrat Creek flows to Elbow Creek, which flows to South Badger Creek and eventually reaches the Gulf of Mexico. Water in Cox Creek flows to the north-northwest oriented Middle Fork Flathead River and eventually reaches the Pacific Ocean. Muskrat Pass is shown as having an elevation of 5974 feet at the continental divide (the figure 9 map contour interval is 40 feet). Elevations west of Muskrat Pass rise to 7375 feet while just to the north and east there is a spot elevation of 7172 feet meaning Muskrat Pass is at least 1200 feet deep. Badger Pass is labeled and is located near the figure 9 center and links the northwest-oriented South Badger Creek valley with the south-southeast and south-southwest oriented Strawberry Creek valley. As previously noted water in South Badger Creek eventually reaches the Gulf of Mexico while water in Strawberry Creek eventually reaches the Pacific Ocean. No spot elevation for Badger Pass is given at the continental divide, although calculating from contour lines the elevation appears to be between 6240 and 6280 feet, which is approximately 300 feet higher than the nearby Muskrat Pass. Cap Mountain in section 28 to the south and west rises to 7612 feet while Family Peak in the section 28 southwest corner (north and east of Badger Pass) rises to 8086 feet. These mountain elevations suggest Badger Pass may be as much as 1300 feet deep. Also note the west to east oriented through valley in section 32 linking the Muskrat Pass through valley with the Badger Pass through valley. This west to east oriented through valley has an elevation of between 6240 and 6280 feet at the drainage divide. The Muskrat Pass through valley, the Badger Pass through valley, and the west to east oriented through valley in section 32 (along with other less deep through valleys in figure 9) are all water eroded features. They were eroded by south-oriented anastomosing flood flow channels which once crossed the figure 9 region. At that time the region was being uplifted and flood waters were still flowing in south and southeast directions along what is now the west to east continental divide. Headward erosion of the deep Middle Fork Flathead River valley beheaded and reversed flood flow to create present day drainage routes west of the present day continental divide and subsequently headward erosion of the Badger Creek valley beheaded and reversed flood flow channels to produce present day figure 9 drainage routes east of the continental divide.

Birch Creek-Gateway Creek drainage divide area

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

 

 

  • Figure 10 illustrates the Birch Creek-Gateway Creek drainage divide area south and slightly east of the figure 8 map area and includes overlap areas with figure 8. The west to east continental divide is labeled and also serves as a county boundary. Badger Pass can be seen near the figure 10 north edge (west of center) and Muskrat Pass is slightly north of the figure 10 edge to the west. Cox Creek flows in a southwest, south, and southwest direction from Muskrat Pass to the figure 10 west edge (north of center). Strawberry Creek flows in a south direction from Badger Pass to near the figure 10 south edge and then turns to flow in a west direction to join north-oriented Clack Creek and to form the north and northwest oriented Middle Fork Flathead River (which flows to the figure 10 west edge just south of Cox Creek, which joins the Middle Fork Flathead River just west of the figure 10 map area). Gateway Creek originates in the figure 10 center area near Gateway Pass as a north and northwest oriented stream and then turns to flow in a southwest direction to join south-oriented Strawberry Creek. Gateway Pass is a through valley between the northwest-oriented Gateway Creek valley segment and a short southeast-oriented South Fork Birch Creek valley segment. At the south end of the southeast-oriented South Birch Creek valley segment South Fork Birch Creek turns to flow in a north-northeast, north-northwest, and north direction to the figure 10 north edge (east of center). Note how the South Fork Birch Creek has a number of north and north-northwest oriented tributaries. Also note how at the south end of the southeast-oriented South Fork Birch Creek valley segment there are through valleys (not as deep as Gateway Pass) linking the South Fork Birch Creek valley with the north-northwest oriented headwaters valley of Trail Creek. After flowing in a north-northwest direction Trail Creek turns to flow in a southwest, west, and northwest direction to join south-oriented Strawberry Creek as a barbed tributary. Study of the figure 10 map area reveals numerous other through valleys crossing the continental divide and other present day drainage divides. These through valleys are relics of the south-oriented anastomosing flood flow channels which crossed the figure 10 map area as the region was being uplifted. These anastomosing south-oriented flood flow channels were dismembered as deeper channels beheaded and reversed less deep diverging flood channels and as deep valleys eroded headward into the region from both the west and the east. In the case of the South Fork Birch Creek valley it was beheaded and reversed by headward erosion of the northeast-oriented Birch Creek valley (north and east of figure 10-see figures 1 and 2). South-oriented flood flow in the Strawberry Creek and Cox Creek flood flow channels was captured when headward erosion of the west-oriented Middle Fork Flathead River valley (north and west of figure 10) beheaded and reversed south-oriented flood flow on the north-northwest oriented Middle Fork Flathead River alignment. The north-northwest oriented Trail Creek valley segment was eroded when headward erosion of the southwest and west oriented Trail Creek valley beheaded and reversed a south-southeast oriented flood flow channel.

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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