West Fork Madison River-Red Rock drainage divide area landform origins Beaverhead and Madison Counties, Montana, USA

Authors


Abstract:

This essay uses topographic map evidence to interpret landform origins between the West Fork Madison River and the Red Rock River in Beaverhead and Madison Counties, Montana. The West Fork Madison River flows in a southeast and northeast direction to join the north oriented Madison River, which at Three Forks, Montana joins the Gallatin and Jefferson Rivers to form the north oriented Missouri River. Elk River is a southeast oriented tributary to the northeast oriented West Fork Madison River. South of the east oriented West Fork Madison River in the Centennial Valley is west oriented Red Rock Creek, which flows to the west and north-northwest oriented Red Rock River. West of the study region the Red Rock River flows to the north-northeast oriented Beaverhead River, which flows to the north-northeast, east, and northeast oriented Jefferson River. The West Fork Madison River-Red Rock River drainage divide and the Elk River-West Fork Madison River drainage divide are crossed by through valleys linking south oriented Red Rock River tributary valleys with the West Fork Madison River valley and south oriented West Fork Madison River tributary valleys with valleys of east oriented Elk River tributaries. This essay interprets these through valleys to have been eroded as diverging and converging south and southeast oriented flood flow channels, which were initially captured by a valley on the Red Rock River alignment, which was probably oriented in an east direction in the eastern Centennial Valley with flood flow moving to a deep south oriented flood flow channel on the present day north oriented Madison River and south oriented Henrys Fork alignment. Floodwaters were derived from a melting thick North American ice sheet located north and east of the essay’s study region. Initially floodwaters flowed at elevations much higher than elevations of the through valley floors and crossed what are today some of the highest regional drainage divides. Flood flow on the deep south-oriented Madison River-Henrys Fork flood flow channel was beheaded by headward erosion of a much deeper northeast oriented valley from space in the deep “hole” the melting ice sheet had occupied. Floodwaters on the north end of the beheaded flood flow channel reversed flow direction to create the north oriented Madison River drainage system and the north oriented Missouri River segment north of the Madison River. The flood flow reversal enabled the deep northeast oriented West Fork Madison River to erode headward across south and southeast oriented flood flow channels west of the Madison River valley. At the same time the deep Jefferson River valley was eroding headward from the reversed flood flow channel to behead south oriented flood flow channels feeding the south-southeast and east oriented flood flow channels on the Red Rock River alignment. Floodwaters on the north and west ends of the beheaded flood flow reversed flow direction to create the west and north-northwest oriented Red Rock River drainage route. These massive flood flow reversals were probably greatly aided by ice sheet related crustal warping that raised mountain ranges and otherwise altered the study region topography as immense melt water floods flowed across the region.

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 are listed on the sidebar category list under their appropriate Missouri River tributary drainage basin, Missouri River segment drainage basin (by state), and/or state in which the Missouri River drainage basin is located.

Introduction

The purpose of this essay is to use topographic map interpretation methods to explore the West Fork Madison River-Red Rock River drainage divide area landform origins in Beaverhead and Madison Counties, Montana and 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 Missouri River drainage basin landform origins research project essays 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 West Fork Madison River-Red Rock River drainage divide area landform evidence in Beaverhead and Madison Counties, Montana will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm.

West Fork Madison River-Red Rock River drainage divide area location map

Figure 1: West Fork Madison River-Red Rock 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 West Fork Madison River-Red Rock River drainage divide in Beaverhead and Madison Counties, Montana and illustrates in the north a region in southwest and south central Montana with the northwest corner of Wyoming in the southeast quadrant of figure 1 and an area in eastern Idaho located in the southwest quadrant of figure 1. The Montana-Idaho state line west of Yellowstone National Park is located on the east-west continental divide, which follows the crest of the Beaverhead and Centennial Mountains from the west edge of figure 1 to the Wyoming state line. The Madison River originates east of the town of West Yellowstone and flows in a northwest direction to Hebgen Lake and then in an east direction to Earthquake Lake before turning to flow in a north direction to join the Gallatin and Jefferson Rivers near Three Forks, Montana to form the north oriented Missouri River. North of figure 1 the Missouri River turns to flow in a north-northwest, northeast and east direction and eventually reaches North Dakota where it turns to flow in a southeast and south direction. The West Fork Madison River is the unlabeled southwest, east, and northeast oriented drainage route located west of Earthquake Lake and north of Upper Red Rock Lake. Upper Red Rock Lake drains in a west direction to Lower Red Rock Lake and then to the Red Rock River, which flows in a west direction to Lima, Montana where it turns to flow in a north-northwest direction to join the north-northeast-oriented Beaverhead River. The Beaverhead River joins the north, southeast, south, and northeast oriented Big Hole River near Twin Bridges, Montana to form the north-northeast, east, and northeast oriented Jefferson River. South of the north oriented Madison River segment is Henrys Lake, which drains to south and southwest oriented Henrys Fork. Henrys Fork joins the northwest and south oriented Snake River west of Rexburg, Idaho. South of figure 1 the Snake River turns to flow in a southwest and then west direction across southern Idaho before turning to flow in a north direction with water eventually reaching the Pacific Ocean. The West Fork Madison River-Red Rock River drainage divide area investigated in this essay is mostly located south of the West Fork Madison River and north of the Red Rock River and its west oriented Red Rock Creek tributary, which flows to Upper and Lower Red Rock Lakes.

A brief look at the big picture erosion history will help understand discussions related to detailed maps shown below. Large volumes of south and southeast oriented floodwaters once flowed across the region shown by figure 1. Floodwaters were derived from the western margin of a melting thick North American ice sheet and were flowing in a south and southeast direction from southwest Alberta and southeast British Columbia to and across the figure 1 region. North oriented rivers in figure 1, including the north oriented Madison River and Missouri River and north-northwest oriented Red Rock River, are generally flowing in valleys that originated as south oriented flood flow channels. The west oriented Red Rock River segment was at one time an east oriented flood flow channel. When floodwaters first flowed across the region the mountain ranges, deep river valleys, and basins between the mountains did not exist and floodwaters could freely flow in south and southeast directions across the region. Mountain ranges and intervening basins emerged as floodwaters flowed across the region and initially floodwaters flowed across what are today high mountain ranges including mountain ranges, which today form the east-west continental divide. The most successful, or deepest, flood flow channels captured floodwaters from adjacent less successful flood flow channels, which resulted in a constantly changing pattern of flood flow channels. Abandoned flood flow channels are today preserved  as through valley or passes crossing present day drainage divides, which are sometimes high mountain ridges.

The Madison River originated as a south oriented flood flow channel, which was subsequently reversed to form the north oriented drainage route seen today. The flood flow reversal was probably indirectly caused by crustal warping that occurred as melt water floods flowed across the region with the crustal warping being related to thick ice sheet presence north and east of figure 1, although the direct cause was headward erosion of a deep northeast oriented valley across Montana (north of figure 1), which beheaded the south oriented flood flow channel supplying floodwaters to the south oriented Madison River flood flow channel on the present-day north oriented Madison River-Missouri River alignment. The deep northeast oriented valley (now the northeast oriented Missouri River valley north of figure 1) was eroding headward from space in the deep “hole” the melting ice sheet had occupied and was capturing the south and southeast oriented ice-marginal melt water floods and diverting the captured floodwaters into space in the deep “hole” where the melting the ice sheet had occupied. This northeast oriented valley was much deeper than the beheaded south oriented flood flow channel and floodwaters on the north end of the beheaded flood flow channel reversed flow direction to create the north oriented Madison River –Missouri River drainage route seen in figure 1. Headward erosion of the deep Jefferson River valley from this reversed flood flow channel next beheaded flood flow channels further to the west and floodwaters on north ends of those beheaded flood flow channels reversed flow direction to create north oriented drainage routes, including the north-northwest oriented Red Rock River segment, which then reversed the east oriented flood flow north of the Centennial Mountains to create the west oriented Red Rock River headwaters segment seen in figure 1.

Detailed location map for West Fork Madison River-Red Rock River drainage divide area

Figure 2: Detailed location map West Fork Madison River-Red Rock River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 2 provides a more detailed location map for the West Fork Madison River-Red Rock River drainage divide area in Beaverhead and Madison Counties, Montana and shows drainage routes not seen in figure 1. The Yellowstone National Park boundary is labeled near the east edge of figure 2 and the Wyoming state line is just east of the Park boundary. West of Yellowstone National Park the continental divide serves as the Montana-Idaho state line and is shown with well-marked dashed line extending from the west edge of figure 2 (south half) along the Centennial Mountains crest ridge to near Henrys Lake and then north around Henrys Lake and then continues in southeast direction to near the southeast corner of edge of figure 2 (in Yellowstone National Park). Green shaded areas are National Forest lands, which generally are located in mountainous regions. The Madison River flows in a west and northwest direction from the east edge of figure 2 to Hebgen Lake. From Hebgen Lake the Madison River then flows in a west direction through Earthquake Lake to the town of Cliff Lake and turns to flow in north-northwest direction to the north edge of figure 2 (west of center). The West Fork Madison River originates north of the Red Rock Lakes Wilderness and flows in a southwest, southeast, east, southeast, and northeast direction to join the Madison River north of the town of Cliff Lake. The Elk River is a major southeast oriented West Fork Madison River tributary. Red Rock Creek is a northwest and west oriented stream originating near the continental divide in the south center area of figure 2 and flowing to Upper and Lower Red Rock Lakes. The Red Rock River originates at Lower Red Rock Lake and flows in a west direction to Lima Reservoir (not labeled in figure 2), which straddles the west edge of figure 2 (south half). The Centennial Mountains are a west-to-east oriented mountain range located south of the Centennial Valley and west oriented Red Rock Creek and the Red Rock River. Henrys Fork originates at Henrys Lake and flows in a southeast, west, and southwest direction to the south edge of figure 2 and eventually joins the south and southwest oriented Snake River. Raynolds Pass north of Henrys Lake is where the south oriented flood flow channel on the present day Madison River-Henrys Fork alignment crossed the present day continental divide. The deep south oriented Madison River-Henrys Fork flood flow channel eroded headward from the deep southwest and west oriented Snake River valley, which was actively eroding headward across the south oriented flood flow as the Beaverhead and Centennial Mountains were emerging. The region investigated in this essay is located south of Elk River and north of Red Rock Creek and the Red Rock River.

Antelope Creek-Red Rock Creek drainage divide area

Figure 3: Antelope Creek-Red Rock Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 3 provides a topographic map of the Antelope Creek-Red Rock Creek drainage divide area. The east-west continental divide serves as the state line and is shown with a dashed line, which extends from the south edge of figure 3 (east of center) to the northeast corner of figure 3. East and south of the continental divide in figure 3 water drains to south oriented Henrys Fork and the Snake River, with water eventually reaching the Pacific Ocean. North and west of the continental divide drainage is to the Missouri River with water eventually reaching the Gulf of Mexico. Raynolds Pass in the northeast quadrant of figure 3 is located in a major north-to-south oriented through valley linking the north oriented Madison River valley (north of figure 3) with the south oriented Henrys Fork valley. The map contour interval for figure 3 is 50 meters and the Raynolds Pass elevation is between 2050 and 2100 meters. Black Mountain to the east of Raynolds Pass rises to more than 3050 meters. West of the continental divide Red Rock Creek flows in a north direction from the south center edge of figure 3 and then turns to flow in a west direction near the south edge of figure 3 to the southwest corner. Antelope Creek is a north oriented stream flowing from near Saddle Mountain (south and east of the center of figure 3) to the north center edge of figure 3 and for purposes of this essay is considered to be a north oriented Madison River tributary (there is some discontinuous surface drainage north of figure 3). West of Saddle Mountain Lone Tree Creek flows in a north direction to join Antelope Creek. South of the Lone Tree Creek headwaters is Lone Tree Pass and south of Lone Tree Pass is a southwest Red Rock Creek tributary. The Lone Tree Pass elevation is between 2300 and 2350 meters. Deer Mountain to west rises to more than 2550 meters and the unnamed mountain (south of Saddle Mountain) to the east also rises to more than 2550 meters suggesting Lone Tree is at least 200 meters deep. Lone Tree Pass was eroded by south oriented flood flow to the Red Rock Creek valley, although the Red Rock Creek valley probably looked very different at that time. Elk Creek is a southwest oriented Red Rock Creek tributary flowing from elongate Elk Lake. Elk Lake is located in a north-northeast-to-south-southwest oriented valley forming the west margin of Hidden Lake Bench. Other lakes in that valley are Hidden Lake and Cliff Lake, which straddles the north edge of figure 3. There is no continuous drainage in the Hidden Lake valley today, although there is a continuous through valley linking the west oriented Red Rock Creek valley with the north oriented Madison River valley. The floor of that continuous through valley between Elk Lake and Hidden Lake has an elevation of between 2050 and 2100 meters and then descends gradually in both directions. Note how the elevation of this Elk Lake-Hidden Lake through valley is almost identical to the elevation of Raynolds Pass through valley to the east. The Raynolds Pass through valley was eroded by south oriented flood flow prior to the reversal of flood flow in the present day north-oriented Madison River valley. The Elk Lake-Hidden Lake through valley was probably initiated as a south oriented flood flow channel, but may have later been used by northeast oriented floodwaters flowing from an east oriented flood flow channel on the Red Rock Creek alignment to the newly reversed and north oriented Madison River valley flood flow channel prior to the reversal of flood flow that created the west and north-northwest oriented Red Rock River drainage route. These flood flow reversals were probably greatly aided by ice sheet related crustal warping that was raising mountain ranges in the region and that was also lowering areas between the rising mountains such as the Henrys Lake basin, the Alaska Basin near the south edge of figure 3, and the Centennial Valley (in southwest corner of figure 3).

Detailed map of Lone Tree Creek-Red Rock Creek drainage divide area

Figure 4: Detailed map of Lone Tree Creek-Red Rock 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 Lone Tree Creek-Red Rock Creek drainage divide area seen is less detail in figure 3. The east-west continental divide serves as the state and county line and can be seen near the east edge of the south half of figure 4. Areas in the Idaho along the south half of the east edge of figure 4 drain to south oriented Henrys Fork. All other areas of figure 4 drain to the Missouri River, although by different routes. Lone Tree Creek originates in section 36 and flows in a north direction to the north edge of figure 4 (east of center). North of figure 4 Lone Tree Creek flows to north oriented Antelope Creek, which flows toward the north oriented Madison River, although does not continue as a surface stream. The northwest and southwest oriented stream in section 1 and then flowing in south direction to the south edge of figure 4 (west of center) flows to west oriented Red Rock Creek, which then flows to the west and north-northwest oriented Red Rock River, which flows to the north-northeast oriented Beaverhead River, which flows to the north-northeast, east, and northeast oriented Jefferson River. The Jefferson River joins the north oriented Madison River (and Gallatin River) at Three Forks, Montana to form the north oriented Missouri River. So, while the water on opposite sides of Lone Tree Pass flows along completely different routes to reach Three Forks, Montana the different routes eventually converge to form the north oriented Missouri River. To understand how these different routes evolved it is necessary to image the water flowing in a south direction and that the different routes are diverging and converging flood flow channels in a giant south oriented anastomosing channel complex. The south oriented flood flow was moving across what were at that time emerging mountain ranges and south oriented flood flow west of figure 4 was being blocked by the emergence of the Beaverhead and Centennial Mountain ranges and was being diverted in an east direction to a deeper south oriented flood flow channel on the present day north oriented Madison River and south oriented Henrys Fork alignment. A massive of reversal of flood flow occurred when the much deeper northeast oriented Missouri River valley eroded headward from space in the deep “hole” the melting North American ice sheet had occupied and beheaded the south oriented flood flow channel to the diverging flood flow channels at Three Forks. The reversal of flood flow in the present day Madison River drainage basin occurred prior to the reversal of flood flow in the present day Red Rock River drainage basin, although the ultimate result of the flood flow reversals was to create the present day Madison River-Red Rock River drainage divide. Lone Tree Pass in figure 4 is evidence south oriented floodwaters once flowed across that drainage divide and is more than 800 feet deep (the map contour interval for figure 4 is 40 feet).

West Fork Madison River-Red Rock Creek drainage divide area

Figure 5: West Fork Madison River-Red Rock Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 5 illustrates the West Fork Madison River-Red Rock Creek drainage divide area west of figure 3 and includes a significant overlap area with figure 3. The Elk Lake-Hidden Lake through valley can be seen in the east fourth of figure 5. Lower Red Rock Lake is located in the southwest corner of figure 5 and is located in the west-to-east oriented Centennial Valley, the west end of which can be seen in the south half of figure 5. The Red Rock River flows in a west direction from Lower Red Rock Lake and further west turns to flow in a north-northwest direction to join the north-northeast Beaverhead River, which joins the north-northeast, east, and northeast oriented Jefferson River. Upper Red Rock Lake straddles the south edge of figure 5 east of Lower Red Rock Lake. Red Rock Creek flows in a west direction just north of Upper Red Rock Lake to Lower Red Rock Lake in the Centennial Valley. Tepee Creek is a southwest and south oriented stream originating near Snowshoe Pass and joining Red Rock Creek north of Upper Red Rock Lake. Snowshoe Creek is an east, south, east, and south oriented Tepee Creek tributary flowing from the west edge of figure 5 (north half). The West Fork Madison River flows in an east-northeast, southeast, and east-northeast direction from the west edge of figure 5 (near northwest corner) to the north edge of figure 5 (east half) and then flows to the north oriented Madison River north and east of figure 5. What makes figure 5 drainage routes interesting is water near the north edge of figure 5 is flowing in an east direction and water near the south edge of figure 5 is flowing in west direction, yet these drainage routes flowing in opposite directions end up converging at Three Forks, Montana to form the north oriented Missouri River. Even more intriguing is evidence of through valleys linking these opposing drainage routes. The West Fork Madison River-Tepee Creek drainage divide is Landon Ridge. Note the Landon Ridge low points near the elbow of capture where the West Fork Madison River turns from flowing in a southeast to a northeast direction low points on Landon Ridge. The map contour interval for figure 5 is 50 meters and the elevation at these low points is between 2200 and 2250 meters. Elevations greater than 2500 meters can found both east and west of those low points suggesting those low points are in fact evidence of south or southeast oriented flood flow channels that existed prior to headward erosion of the deeper northeast oriented West Fork Madison River valley, which captured the southeast oriented flood flow. The southeast oriented flood flow would have been moving to the west end of the present day Centennial Valley and then probably to the deep south oriented Henrys Fork valley seen south of Raynolds Pass in figure 3. Headward erosion of the deeper West Fork Madison River captured the south and southeast oriented flood flow and diverted the captured floodwaters to the newly reversed and then north oriented Madison River valley.

Detailed map of West Fork Madison River-Tepee Creek drainage divide area

Figure 6: Detailed map of West Fork Madison River-Tepee Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 6 provides a detailed topographic map of the West Fork Madison River-Tepee Creek drainage divide area seen in less detail in figure 5. Tepee Creek flows in a southwest direction across the southwest quadrant of figure 6 and south of figure 6 turns to flow in a south direction to join west oriented Red Rock Creek with water eventually reaching the north-northeast, east, and northeast oriented Jefferson River. Snowshoe Creek flows in an east and south direction from the east center edge of figure 6 to the south edge of figure 6 (near southwest corner) and south of figure 6 joins south oriented Tepee Creek. The West Fork Madison River flows in a southeast and northeast direction from the north edge of figure 6 (west half) to the north edge of figure 6 (east half) and north and east of figure 6 joins the north oriented Madison River. The West Fork Madison River-Tepee Creek drainage divide is named Landon Ridge, which extends in a southeast and then in a northeast direction just south of the southeast and northeast oriented West Fork Madison River. The map contour interval for figure 6 is 20 feet in the west half and 40 feet in the east half. Note the low point in Landon Ridge in the southeast quadrant of section 5 where the Landon Ridge elevation drops to less than 7360 feet (but is still more than 7320 feet). Landon Ridge near the west edge of figure 6 rises to 7871 feet and west of figure 6 rises to 8173 feet. Between the low point in section 5 and Snowshoe Pass Landon Ridge rise to more than 7640 feet and east of figure 6 rises to more than 8240 feet.  These elevations suggest the low point in the southeast quadrant of section 5 is evidence the southeast oriented West Fork Madison River segment alignment is developed on the alignment of what was at one a southeast oriented flood flow channel moving floodwaters to the Centennial Valley west end. The southeast oriented flood flow channel was first captured by headward erosion of southwest oriented Tepee Creek valley, which eroded headward from the south oriented Tepee Creek valley (perhaps as a flood flow reversal was taking place in the CEntennial Valley). Next headward erosion of the deeper northeast oriented West Fork Madison River valley captured the southeast oriented flood flow channel ending all southeast oriented flood flow across the present day Landon Ridge. This history begins with flood flow in the Centennial Valley being oriented in an east direction (and probably flood flow in the present day north oriented Madison River being in a south direction) and ends with drainage in the Centennial Valley being oriented in a west direction and drainage in the Madison River valley being oriented in a north direction.

West Fork Madison River-Metzel Creek drainage divide area

Figure 7: West Fork Madison River-Metzel Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 7 illustrates the West Fork Madison River-Metzel Creek drainage divide area west and slightly north of figure 5 and includes a significant overlap area with figure 5. The north edge of the Centennial Valley is located along the south margin of figure 7. The Eureka Basin is located in Madison County in the northwest quadrant of figure 7 and the West Fork Madison River flows in a southwest direction to the Eureka Basin where the West Fork Madison River turns to flow in a southeast, east-northeast, southeast, and northeast direction to the east center edge of figure 7. Landon Ridge can be seen just south of the West Fork Madison River valley in the east half of figure 7. Patchtop Mountain is located near the center of figure 7 and Snowshoe Creek originates south of Patchtop Mountain and flows in an east, south, east, and south direction to join southwest and south oriented Tepee Creek, which was seen in earlier figures. Metzel Creek originates west of Patchtop Mountain and flows in a south direction to the south edge of figure 7 (west of center) and joins the west oriented Red Rock River south of figure 7. Note how the south oriented Metzel Creek valley is linked by a north-to-south oriented through valley with the southeast oriented West Fork Madison River valley. The map contour interval for figure 7 is 50 meters and the through valley floor elevation at the drainage is between 2300 and 2350 meters. Patchtop Mountain to the east rises to 2555 meters and the unnamed hill or mountain directly to the west rises to 2529 meters suggesting the through valley is approximately 200 meters deep. Between Patchtop Mountain and Landon Ridge another through valley links the West Fork Madison River valley with the east oriented Snowshoe Creek valley. This eastern through valley also has a floor elevation at the drainage divide of between 2300 and 2350 meters and Landon Ridge to the east rises to 2491 meters.  These through valleys provide evidence of what were once diverging south oriented flood flow channels. One of the diverging flood flow channels followed the alignment of the present day Metzel Creek valley alignment while the other diverging flood flow channel continued to the Snowshoe Creek alignment. Headward erosion of a deeper east oriented West Fork Madison River valley captured the south and southeast oriented flood flow and diverted the floodwaters to what at that time was the newly reversed flood flow channel on the present day north oriented Madison River-Missouri River alignment

Detailed map of West Fork Madison River-Metzel Creek drainage divide area

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

Figure 8 provides a detailed topographic map of the West Fork Madison River-Metzel Creek drainage divide area seen in less detail in figure 7. The map contour interval for figure 8 is 20 feet in the south half and 40 feet in the north half. The West Fork Madison River flows in a southeast direction from the north center edge of figure 8 to near the east center edge of figure 8 and then turns to flow in a northeast direction. Patchtop Mountain is located in section 32 in the southeast quadrant of figure 8. Metzel Creek originates in section 25 (in northwest quadrant of figure 8) and flows in a southeast and south direction to the south center edge of figure 8. Note in the southwest quadrant of section 30 how the road makes use of a through valley linking the southeast oriented West Fork Madison River valley with the deeper south oriented Metzel Creek valley. The through valley elevation where the road crosses the drainage divide is shown as 7697 feet. Patchtop Mountain rises to 8383 feet and the high point in section 26 to the west is shown as 8298. These elevations suggest the through valley is at least 600 feet deep. Note south-southwest oriented Miner Creek, which joins the West Fork Madison River just north of the through valley. The much deeper Metzel Creek valley to the south suggests the through valley was eroded by a south oriented flood flow channel on the Miner Creek-Metzel Creek alignment, which was captured by headward erosion of the slightly deeper southeast oriented West Fork Madison River valley. For a time at least this was a point of converging southeast and south-southwest flood flow channels as well as being a point of diverging south and southeast oriented flood flow channels. Based on evidence seen in figure 8 headward erosion of the south oriented Metzel Creek valley came very close to capturing the southeast oriented West Fork Madison River flood flow channel.

Elk River-West Fork Madison River drainage divide area

Figure 9: Elk River-West Fork Madison River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 9 illustrates the Elk River-West Fork Madison River drainage divide area east and north of figure 7 and includes a significant overlap area with figure 7. The map contour interval for figure 9 is 50 meters. Patchtop Mountain is located near the southwest corner of figure 9. The West Fork Madison River flows from the west edge of figure 9 (north of Patchtop Mountain) in a southeast, east-northeast, southeast, northeast, and north-northeast direction to the east edge of figure 9 (north half) and joins the north oriented Madison River north and east of figure 9. Elk River flows from north of figure 9 to Elk River Basin (near north edge of northwest quadrant of figure 9) and then in a southeast direction to join the northeast oriented West Fork Madison River. Crater Ridge is located south of Elk River Basin and Barnett Creek is an east-southeast and east-northeast oriented Elk River tributary north of Crater Ridge while Hellroaring Creek is an east-northeast oriented Elk River tributary south of Crater Ridge. Fossil Creek is a south oriented West Fork Madison River tributary originating a short distance west of the Hellroaring Creek headwaters. East of Fossil Creek is Cascade Mountain, which rises to 2867 meters. Further east is Divide Mountain, which rises to more than 2900 meters. Between Cascade Mountain and Divide Mountain is south oriented Cascade Creek and a through valley linking the south oriented Cascade Creek valley with the east oriented Hellroaring Creek valley. The through valley floor elevation is between 2700 and 2750 meters suggesting the through valley is more than 100 meters deep. The through valley was eroded by south oriented flood flow prior to headward erosion of the deeper east-northeast oriented Hellroaring Creek valley. Other than the Cascade Creek through valley Cascade Mountain and Divide Mountain together form a large upland region bounded on the west by south oriented Fossil Creek, on the south by the West Fork Madison River, and on the north and east by Hellroaring Creek and Elk River. Note how through valleys link a northeast oriented Barnett Creek tributary valley with a southeast oriented Hellroaring Creek tributary valley and also link the south oriented Fossil Creek valley with the east-northeast oriented Hellroaring Creek valley. The Barnett Creek-Hellroaring Creek through valley has an elevation at the drainage divide of between 2700 and 2750 meters while the Hellroaring Creek-Fossil Creek through valley is slightly lower with an elevation of between 2650 and 2700 meters. These through valleys provide evidence of a south oriented flood flow channel on the Fossil Creek alignment that was partially beheaded by headward erosion of the east-northeast oriented Hellroaring Creek valley and completely beheaded at a later time by headward erosion of the Barnett Creek valley. Ever changing patterns of anastomosing flood flow channels, such as those described here, shaped landforms in the region illustrated in figure 9 with headward erosion of deep valley repeatedly capturing flood flow channels and then being captured by headward of even deeper valleys.

Detailed map of Hellroaring Creek-Fossil Creek drainage divide area

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

Figure 10 provides a detailed topographic map of the Hellroaring Creek-Fossil Creek drainage divide area seen in less detail in figure 9. The map contour interval for figure 10 is 40 feet. Hellroaring Creek flows in an east direction near the north edge of the northeast quadrant of figure 10. Note the southeast oriented Hellroaring Creek tributary in section 34. A through valley in the northwest corner of section 34 links that southeast oriented Hellroaring Creek tributary valley with a northeast oriented Barnett Creek tributary valley (not seen in figure 10). The through valley floor elevation at the drainage divide is between 8840 and 8880 feet. Elevations to the east (north of figure 10) rise to 9328 feet and near the northwest corner of figure 10 elevations rise to more than 9480 feet suggesting the through valley is at least 440 feet deep. Fossil Creek originates in the southwest corner of section 34 and the south half of section 33 and flows in a south direction to the south edge of figure 10 (west half). Note the north-to-south oriented through valley near the west edge of section 34 linking the south oriented Fossil Creek valley with the southeast oriented Hellroaring Creek tributary valley. Cascade Mountain is east of Fossil Creek in section 10 (just north of south edge of figure 10) and rises to 9406 feet. The south oriented stream east of Cascade Mountain and flowing from section 2 through section 11 to the south edge of figure 10 is Cascade Creek. Note the north-to-south oriented through valley in section 2 linking the south oriented Cascade Creek valley with the east oriented Hellroaring Creek valley. The through valley floor elevation at the drainage divide is between 8960 and 9000 feet. East of the south oriented Cascade Creek valley is Divide Mountain, which rises to 9529 feet suggesting the through valley is at least 400 feet deep. The described through valleys and other similar through valleys seen in figure 10 are water-eroded features and were eroded by south oriented flood flow channels. Headward erosion of the deep east oriented Hellroaring Creek valley beheaded the south oriented flood flow channel on the Cascade Creek alignment, which had been fed by the flood flow on the southeast oriented Hellroaring Creek tributary alignment. Next headward erosion of the northeast oriented Barnett Creek tributary valley north of figure 10 beheaded the flood flow channel on the southeast oriented Hellroaring Creek alignment and also a diverging south oriented flood flow channel on the Fossil Creek alignment.

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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