Moose Creek-Big Hole River drainage divide area landform origins, Silver Bow and Madison Counties, Montana, USA

Authors


Abstract:

This essay uses topographic map evidence to interpret landform origins between Moose Creek and the Big Hole River in Silver Bow and Madison Counties, Montana. The Big Hole River flows in a north, northeast, southeast, and south direction around the Pioneer Mountains in Beaverhead County and then makes a large U-turn in Madison County to flow in a northeast direction to join the north-northeast oriented Beaverhead River and to form the northeast oriented Jefferson River, which flows to the north oriented Missouri River. Moose Creek is a southwest oriented tributary to the south oriented Madison County Big Hole River segment and the study region investigated in this essay is located south and east of Moose Creek, east of the south oriented Big Hole River segment, north the Madison County Big Hole River U-turn, and west of the northeast oriented Madison County Big Hole River segment. Southeast oriented and barbed tributaries flow to the northeast oriented Madison County Big Hole River segment. Shallow through valleys cross Silver Bow and Madison County drainage divides between southwest oriented Big Hole River tributaries and also drainage divides between the southwest oriented tributaries and the southeast oriented Big Hole River tributaries providing evidence of former southeast oriented flood flow channels. Northwest oriented McCartney Creek flows to the south oriented Big Hole River segment as a barbed tributary while being linked by a through valley north of McCartney Mountain with a southeast oriented stream, which flows to the northeast oriented Madison County Big Hole River segment as a barbed tributary. The barbed tributaries, drainage divides crossed by through valleys, and the Madison County Big Hole River U-turn all provide evidence of southeast and south oriented flood flow that was captured by a massive flood flow reversal in the present day north oriented Beaverhead and Jefferson River valley. The massive flood flow reversal probably occurred as ice sheet related crustal warping raised mountain ranges and otherwise tilted the continent so as to cause south oriented melt water floods to flow in north and northeast directions toward space in a deep “hole” the ice sheet had been formed and was occupying and that was being opened up by ice sheet melting.

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 Moose Creek-Big Hole River drainage divide area landform origins in Silver Bow 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 Moose Creek-Big Hole River drainage divide area landform evidence in Silver Bow and Madison Counties, Montana will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm.

Moose Creek-Big Hole River drainage divide area location map

Figure 1: Moose Creek-Big Hole 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 Moose Creek-Big Hole River drainage divide area in Silver Bow and Madison Counties, Montana and illustrates a region in southwestern Montana with a small region in Idaho visible in the southwest corner of figure 1 and a smaller region at the northwest corner of Wyoming seen in the southeast corner of figure 1. The Missouri River (unlabeled in figure 1) is located in the east half of figure 1 and is formed at Three Forks, Montana at the confluence the north and northwest oriented Gallatin River, north oriented Madison River, and northeast, east, and northeast oriented Jefferson River. From Three Forks the Missouri River flows in a north and north-northwest direction to Canyon Ferry Lake (large reservoir flooding the Missouri River valley along the north edge of figure 1) . North of figure 1 the Missouri River turns to flow in a northeast and east direction to North Dakota where it turns to flow in a southeast and south direction with water eventually reaching the Gulf of Mexico. The Jefferson River is formed at the confluence of Big Hole and Beaverhead Rivers near Twin Bridges, Montana. Note how the Big Hole River flows in a north and northeast direction west of the Pioneer Mountains and then turns to flow in an east-southeast direction to the town of Divide. From Divide the Big Hole River flows in a south and northeast direction as it makes a large U-turn to join the north-northeast oriented Beaverhead River. Moose Creek is a southwest oriented stream joining the south oriented Big Hole River as a barbed tributary between the towns of Divide and Melrose. North of the south oriented Big Hole River segment are headwaters of north and northwest oriented Clark Fork, which flows from Warm Springs to Deer Lodge and the north edge of figure 1. North of figure 1 Clark Fork turns to flow in a northwest direction with water eventually reaching the Pacific Ocean. The Moose Creek-Big Hole River drainage divide area in Silver Bow and Madison Counties is located in the region of the Big Hole River U-turn, where the Big Hole River turns from flowing in a south direction to flowing in a northeast direction to join the northeast oriented Beaverhead River and to form the northeast oriented Jefferson River.

Before looking at detailed maps of the Moose Creek-Big Hole River drainage divide area a brief look at the big picture erosion history is appropriate. 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 rapidly 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 are generally flowing in valleys that originated as south oriented flood flow channels. The north oriented drainage system seen on both sides of the east-west continental divide developed during massive flood flow reversals that occurred as mountain ranges and high plateaus were uplifted by ice sheet related crustal warping and occurred as floodwaters flowed across the region. In addition, deep flood water erosion of valleys and basins surrounding the rising mountain ranges contributed to the emergence of present day mountain ranges. In time the ice sheet related crustal warping combined with deep glacial erosion under the ice sheet created a deep “hole” in which the ice sheet was located. Eventually as the ice sheet melted there came a time when elevations on the ice sheet surface (at least in the south) were lower than elevations along the deep “hole” southwest rim in Montana where the immense south and southeast oriented ice marginal melt water floods were flowing. Deep northeast oriented valleys then eroded headward from space in the deep “hole” being opened up by the ice sheet melting to capture the south and southeast oriented melt water floods in present day eastern and central Montana. At the same time headward erosion of the south and west oriented Columbia River valley and tributary valleys from the Pacific Ocean beheaded and reversed southeast oriented flood flow channels moving floodwaters to western Montana.

The northeast oriented Missouri River valley segment north of figure 1 and its east and northeast oriented tributary valleys eroded headward from the deep “hole” across the south and southeast oriented flood flow. Northwest oriented Missouri River tributary valleys and the north-northwest oriented Missouri River valley segment seen in figure 1 were eroded by reversals of flood flow on north and northwest ends of beheaded flood flow channels. Alignments of the present day north oriented Madison River, north and northwest oriented Gallatin River, and north oriented Jefferson River  and of many of their tributaries were established initially as south oriented flood flow channels, which were reversed and deepened during massive upper Missouri River drainage basin flood flow reversal events. Uplift of the Yellowstone Plateau and mountain ranges south of figure 1 probably contributed significantly to the massive flood flow reversals. Reversal of flood flow to create the present day north oriented Jefferson River valley captured south oriented flood flow on the present day north oriented Clark Fork-Big Hole River alignment, which created the present day Big Hole River U-turn east of the Pioneer Mountains. The north oriented Big Hole River segment west of the Pioneer Mountains flows on the alignments of what began as south oriented flood flow channels. In other words the Big Hole River U-turn illustrated and discussed in this essay was formed when headward erosion of a deep valley from space in the deep “hole” being opened up by ice sheet melting captured south oriented melt water flood flow in southwest Montana.

Detailed location map for Moose Creek-Big Hole River drainage divide area

Figure 2: Detailed location map Moose Creek-Big Hole 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 Moose Creek-Big Hole River drainage divide area in Silver Bow and Madison Counties, Montana and shows drainage routes not seen in figure 1. County boundaries are shown and Silver Bow and Madison Counties are labeled. Beaverhead County is the unlabeled county south and west of Silver Bow and Madison Counties. Green shaded areas are National Forest lands, which generally are located in mountainous regions. The Big Hole River flows in a southeast and south-southeast direction and serves as the Silver Bow–Beaverhead County boundary from the west edge of figure 2 (near northwest corner) to Melrose. From Melrose the Big Hole River flows in a south and northeast direction and for a distance serves as the Madison-Beaverhead County boundary before joining the north-northeast oriented Beaverhead River near Twin Bridges and forming the Jefferson River. From the Twin Bridges area the Jefferson River flows in northeast direction to Cardwell and then in a southeast and northeast direction to the east edge of figure 2 (near northeast corner). Moose Creek is the southwest oriented stream flowing from near Mount Humbug in Silver Bow County to join the south-southeast oriented Big Hole River near Maiden Rock. Camp Creek is the southwest oriented tributary serving as the Silver Bow-Madison County boundary and joining the Big Hole River at Melrose. South of Melrose northwest oriented McCartney Creek flows to the south oriented Big Hole River as a barbed tributary. Note how McCartney Creek flows in a northwest direction on the same alignment as a southeast oriented stream, which flows to the northeast oriented Big Hole River as a barbed tributary. Note also other southeast oriented streams flowing to the northeast oriented Big Hole River segment and to the Jefferson River as barbed tributaries. The southeast oriented tributaries flowing to a northeast oriented river and the Big Hole River U-turn are evidence of south and southeast oriented flood flow channels that once crossed the region. The northwest oriented Big Hole River barbed tributary and the northwest oriented Beaverhead and Jefferson River tributaries seen in figure 2 were formed by reversals of flood flow on northwest ends of beheaded southeast oriented flood flow channels. Evidence for a southeast oriented flood flow channel north of McCartney Mountain is seen in figure 7 below. Prior to the flood flow reversal that created the north-northeast oriented Jefferson and Beaverhead Rivers and that captured south oriented flood flow on the south oriented Big Hole River alignment flood flow moved in a south direction on the Beaverhead River alignment to the actively eroding Snake River valley and tributary valleys in Idaho, which is south of figure 1. Deep mountain passes or through valleys provide evidence of the former south oriented flood flow channel routes, which were blocked as crustal warping raised high mountain ridges faster than the south oriented flood flow channels could erode their channel floors.

Moose Creek-Camp Creek drainage divide area

Figure 3: Moose Creek-Camp 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 Moose Creek-Camp Creek drainage divide area. The Big Hole River flows in a south-southeast direction from the northwest corner of figure 3 to the south edge of figure 3 (west half). Divide is the town located near the northwest corner of figure 3. Melrose is the town in the Big Hole River valley in the southwest quadrant of figure 3. Camp Creek is the southwest tributary serving as the Silver Bow-Madison County boundary and joining the Big Hole River near Melrose. The southwest oriented tributary joining the Big Hole River in the northwest quadrant of figure 3 is Moose Creek. The southwest oriented tributary between Moose Creek and Camp Creek is Soap Gulch. Note how the highway between Divide and Melrose does not follow the Big Hole River valley south of Moose Creek (as does the railroad), but instead uses a parallel valley. The north end of that parallel valley is drained by a north oriented Moose Creek tributary while the south end is drained by a south oriented Big Hole River tributary. The map contour interval for figure 3 is 50 meters and the floor of that parallel through valley at the Moose Creek-Big Hole River drainage divide has an elevation of between 1700 and 1750 meters. The hill separating that parallel through valley from the Big Hole River valley rises to more than 2000 meters meaning the through valley is at least 250 meters deep. The through valley is a water-eroded feature and was eroded as a diverging and converging flood flow channel at the same time the present day Big Hole River valley was being eroded. Eventually the Big Hole River-Moose Creek valley was eroded deeper and it beheaded south oriented flood flow in the parallel flood flow channel. Floodwaters on the north end of the beheaded flood flow channel reversed flow direction to erode the north oriented Moose Creek tributary valley. Study of the map area in figure 3 reveals other much higher elevation and shallower northwest to southeast oriented through valleys crossing drainage divides between the southwest oriented Big Hole River tributaries. These higher elevation through valleys provide evidence that southeast oriented flood flow once moved across a surface where there were no deep intervening southwest oriented Big Hole River tributary valleys. Headward erosion of the southwest oriented Camp Creek valley captured the southeast oriented flood flow first. Next headward erosion of the southwest oriented Soap Creek valley captured the southeast oriented flood flow. Headward erosion of the southwest oriented Moose Creek valley then captured the southeast oriented flood flow

Detailed map of Moose Creek-Big Hole River drainage divide area

Figure 4: Detailed map of Moose Creek-Big Hole River 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 Moose Creek-Big Hole River drainage divide area seen is less detail in figure 3. The Big Hole River flows in a southeast direction across the southwest quadrant of figure 4 and makes an interesting incised meander in the Maiden Rock area in sections 32 and 5 just to the north. Moose Creek flows in a southwest direction from the north center edge of figure 4 to join the Big Hole River at the Maiden Rock incised meander. The map contour interval for figure 4 is 40 feet. Maiden Rock, around which the Big Hole River flows, stands at least 200 feet higher than the floor of the more direct abandoned valley seen along the west edge of figure 4. But that valley is small compared to the much larger and deeper valley used by the highway between the Moose Creek valley near the north edge of figure 4 and the Big Hole River valley near the south edge of figure 4. The floor of that large north-to-south oriented through valley where the highway crosses the drainage divide has an elevation of between 5640 and 5680 feet. The high point in the southeast corner of section 4 to the west is 6533 feet and elevations near the northeast corner of figure 4 rise even higher suggesting the through valley is at least 850 feet deep. The through valley width can be seen on figure 4 (sections in figure 4 are one mile squares). The through valley provides evidence of a major south oriented flood flow channel that was beheaded by headward erosion of the deeper Big Hole River and Moose Creek valleys. Floodwaters on the north end of the beheaded flood flow channel reversed flow direction to erode the northwest oriented Moose Creek tributary valleys seen in section 34. Headward erosion of the deeper Big Hole River and Moose Creek valleys to behead the south oriented flood flow could not have taken place unless floodwaters were simultaneously flowing along the present day Moose Creek-Big Hole River valley alignment and also through the valley now occupied by the highway. In other words the valleys seen in figure 4 were at one time diverging and converging flood flow channels such as are found in anastomosing flood flow channel complexes. At that time volumes of water flowing across the map area seen in figure 4 were much greater than volumes of water in the Big Hole River today.

Camp Creek-Rochester Creek southwest drainage divide area

Figure 5: Camp Creek-Rochester Creek southwest drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 5 illustrates the Camp Creek-Rochester Creek southwest drainage divide area south and east of figure 3 and includes a significant overlap area with figure 3. Figure 9 below illustrates the Camp Creek-Rochester Creek northeast drainage divide area and shows more Camp Creek-Rochester Creek drainage divide features. The Big Hole River flows in a south direction along the west edge of figure 5. Camp Creek is the southwest oriented Big Hole River tributary serving as the Silver Bow-Madison County boundary and flowing from the north center edge of figure 5 to the town of Melrose. Rochester Creek is the south and southeast oriented stream flowing from the Dougherty Butte area (north center area of figure 5) to the town of Rochester and then to just north of the southeast corner of figure 5. In this discussion our interest is in the southeast oriented Rochester Creek tributary originating near the Camp Creek valley and joining Rochester Creek near the town of Rochester. Note how that tributary drains the southeast end of a northwest-to-southeast oriented through valley, which is drained in the northwest by a much shorter northwest oriented Camp Creek tributary. The map contour interval for figure 5 is 50 meters and the through valley elevation at the drainage divide is between 1950 and 2000 meters. The hill to the southwest rises to more than 2100 meters while the hill to the northeast rises even higher suggesting the through valley is at least 100 meters deep. While the through valley may be related to geologic structures it is also a water-eroded feature and is evidence of a former southeast oriented flood flow channel. At the time floodwaters flowed in the flood flow channel the deeper southwest oriented Camp Creek valley did not exist and the floodwaters were coming from northwest of the Camp Creek valley and flowing to the actively eroding Rochester Creek valley, which was probably eroding headward from a south oriented flood flow channel on the present day north-northeast oriented Big Hole River alignment (not seen in figure 5, but east of figure 5). Headward erosion of the deep southwest oriented Camp Creek valley captured the southeast oriented flood flow and floodwaters on the northwest end of the beheaded flood flow channel reversed flow direction to erode the short northwest oriented Camp Creek tributary valley. Note the short southeast oriented Camp Creek tributary located on the same alignment northwest of the through valley.

Detailed map of Camp Creek-Rochester Creek southwest drainage divide area

Figure 6: Detailed map of Camp Creek-Rochester Creek southwest 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 Camp Creek-Rochester Creek southwest drainage divide area seen in less detail in figure 5. Camp Creek flows in a southwest direction across the northwest quadrant of figure 6. The southeast oriented Rochester Creek tributary seen in figure 5 flows from section 22 to the east edge of figure 6 (in section 26). Note in the northwest quadrant of section 22 the northwest-to-southeast oriented through valley linking the southeast oriented Rochester Creek tributary valley with a west and northwest oriented Camp Creek tributary valley. The northwest oriented stream flows to southwest oriented Camp Creek as a barbed tributary. The map contour interval for figure 6 is 40 feet and the through valley floor elevation at the drainage divide is between 6440 and 6480 feet. The high point near the south edge of section 21 is 6939 feet and elevations greater than 7000 feet can be seen near the northeast corner of figure 6. These elevations suggest the through valley is approximately 500 feet deep. Another narrower northwest-to-southeast oriented through valley can be seen in section 29 (near southeast corner of figure 6) and links a different northwest oriented (and barbed) Camp Creek tributary valley with the valley of a west and south oriented stream, which south of figure 6 flows to the south oriented Big Hole River. The floor elevation of this second through valley at the drainage divide is between 5920 and 5960 feet. The ridge to the west in section 29 rises to at least 6160 feet and elevations higher than 6200 feet can be seen in section 29 just to the east of the through valley. Based on these elevations the second through valley is at least 200 feet deep. The first and much larger and higher level flood flow channel was eroded by southeast oriented flood flow moving water to a south oriented flood flow channel on the present day north-northeast oriented Big Hole River alignment. The second flood flow channel was eroded by south-southeast oriented flood flow moving water to what was then the actively eroding south oriented Big Hole River valley located west of figure 6. Flood flow was coming from north and northwest of figure 6. Headward erosion of the much deeper south oriented Big Hole River valley and its tributary southwest oriented Camp Creek valley captured the south and southeast oriented flood flow and diverted the floodwaters in a southwest and south direction. It is possible at that time ice sheet related crustal warping was still raising mountain ridges in the region with greater uplift occurring in the northeast than in the southwest.

Big Hole River-Big Hole River drainage divide area

Figure 7: Big Hole River-Big Hole River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 7 illustrates the Big Hole River-Big Hole River drainage divide area south of figure 5 and includes a significant overlap area with figure 5. This map has been reduced to show the Big Hole River U-turn. The Big Hole River flows in a south direction along the west edge of figure 7 and then turns to flow in southeast direction across the southwest corner of figure 7. Just south of the south edge the Big Hole River turns to flow in a northeast direction to join the north-northeast oriented Beaverhead River near the east edge of figure 7 and the town of Twin Bridges. Rochester is the small town located near the north center edge of figure 7. Rochester Creek flows in a southeast direction from Rochester to join the north-northeast oriented Big Hole River near the State Children’s Center. McCartney Mountain is the forested mountain surrounded by the Big Hole U-turn. The northwest oriented and barbed Big Hole River tributary north of McCartney Mountain is McCartney Creek. Note how a northwest-to-southeast oriented through valley links the northwest-oriented McCartney Creek valley with an unnamed east-southeast oriented Big Hole River tributary valley. The map contour interval for figure 7 is 50 meters and the through valley floor elevation is between 1800 and 1850 meters. Bell Peak on McCartney Mountain reaches an elevation of 2397 meters and while not seen in figure 7 elevations greater than 3000 meters can be found north and east of the through valley. These elevations suggest the through valley may be more than 500 meters deep. While the through valley appears to be related to regional geologic structures it is also a water-eroded feature and was eroded by southeast oriented flood flow prior to being beheaded by headward erosion of the deeper south oriented Big Hole River (to the west). Floodwaters on the northwest end of the beheaded flood flow channel reversed flow direction to erode the northwest oriented McCartney Creek valley. The Big Hole River U-turn and the southeast oriented barbed tributaries flowing to the north-northeast oriented Big Hole River segment provide overwhelming evidence of the capture of a major south oriented flood flow channel by a major flow reversal on what had been a converging south oriented flood flow channel. The flood flow reversal occurred probably because ice sheet related crustal warping was uplifting areas to the south creating a topographic barriers across the former south oriented flood flow routes. Also headward erosion of a deep northeast oriented Missouri River valley segment from space in the deep “hole” being opened by ice sheet melting beheaded south oriented flood flow channels (north and east of figure 7), which caused floodwaters on north ends of the beheaded flood flow channels to reverse flow direction and to form the north oriented western Montana Missouri River drainage system.

Moose Creek-Wickiup Creek drainage divide area

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

Figure 8 provides a topographic map of the Moose Creek-Wickiup Creek drainage divide area north and east of figure 3 and includes an overlap area with figure 3. The Big Hole River can be seen flowing in a south direction in the southwest corner of figure 8. Moose Creek flows in a southwest direction from near Gold Hill in the north center area of figure 8 to the west edge (south of center) and joins the south oriented Big Hole River west of figure 8. Camp Creek also originates in the Gold Hill region and flows in a south and southwest direction to the south edge of figure 8 (west of center). Wickiup Creek is a south-southeast oriented Camp Creek tributary located near the center of figure 8. Fish Creek in the northeast corner area of figure 8 is an east and southeast oriented Jefferson River tributary. Note how the south-southeast oriented Wickiup Creek valley is linked by a shallow through valley with the valley of a north-northwest oriented Moose Creek tributary. The map contour interval for figure 8 is 50 meters and the through valley floor elevation at the drainage divide is between 2250 and 2300 meters. To the southwest the ridge rises to more than 2500 meters while Red Mountain to the northeast rises to more than 3000 meters. These elevations suggest the Moose Creek-Wickiup Creek through valley is at least 200 meters deep. The Moose Creek-Wickiup Creek through valley is a remnant of another southeast oriented flood flow channel that crossed the region prior to headward erosion of the deeper southwest oriented Moose Creek valley. Apparently the southeast oriented flood flow was captured by headward erosion of the deep southwest oriented Camp Creek valley (from the south oriented Big Hole River valley) prior to headward erosion of deep southwest oriented Moose Creek valley. The southeast flood flow was then able to erode the south-southeast oriented Wickiup Creek valley before being captured by headward erosion of the deep southwest oriented Moose Creek valley. Floodwaters on the northwest end of the beheaded flood flow channel reversed flow direction to erode the north-northwest oriented Moose Creek tributary valley.

Camp Creek-Rochester Creek northeast drainage divide area

Figure 9: Camp Creek-Rochester Creek northeast drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 9 illustrates the Camp Creek-Rochester Creek northeast drainage divide area north and east of figure 5 and includes an overlap area with figure 5. The Jefferson River flows in a north-northeast direction across the southeast corner of figure 9. Canyon Creek is the southeast oriented stream originating in the Deer Lodge National Forest in the north center area of figure 9 and joining the north-northeast Jefferson River as a barbed tributary in the southeast corner of figure 9. Cherry Creek is the labeled southeast oriented stream flowing across the northeast quadrant of figure 9 and joining the Jefferson River as a barbed tributary just east of the east edge of figure 9 near Silver Star. Camp Creek flows in a south-southwest and southwest direction from the north edge of figure 9 (west half) to the west edge of figure 9 (south of center) and joins the south oriented Big Hole River west of figure 9. Wickiup Creek is the south-southeast oriented Camp Creek tributary in the northwest corner region of figure 9. Rochester is the small town near the south edge of figure 9 (west of center). Rochester Creek originates west of Dougherty Butte (north of Rochester) and flows in a south direction to Rochester and then turns to flow in a southeast direction to join the northeast oriented Big Hole River as seen in figure 7. Note how north of Dougherty Butte a through valley links the south oriented Rochester Creek headwaters valley with a northwest oriented Camp Creek tributary valley, which is located on approximately the same alignment as the south-southeast oriented Wickiup Creek valley. The map contour interval for figure 9 is 50 meters and the through valley floor elevation at the drainage divide is between 2050 and 2100 meters. To the southwest along the Camp Creek-Rochester Creek drainage divide elevations rise to 2250 meters. To the northeast elevations rise much higher, suggesting the through valley is at least 150 meters deep. The through valley is another segment of the southeast oriented flood flow channel seen crossing the Moose Creek-Wickiup Creek drainage divide in figure 8. In other words the Rochester Creek valley was eroded by south and southeast oriented flood flow derived from sources north and west of the Moose Creek valley. Headward erosion of the deep southwest oriented Camp Creek valley beheaded the southeast oriented flood flow channel and floodwaters on the northwest end of the beheaded flood flow channel reversed flow direction to erode the northwest oriented Camp Creek tributary valley. As seen in figure 8 this process was repeated when headward erosion of the deep southwest oriented Moose Creek valley captured the flood flow.

Detailed map of Camp Creek-Rochester Creek northeast drainage divide area

Figure 10: Detailed map of Camp Creek-Rochester Creek northeast 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 Camp Creek-Rochester Creek northeast drainage divide area seen in less detail in figure 9. Camp Creek flows in a southwest direction across the northwest quadrant of figure 10 and south and west of figure 10 joins the south oriented Big Hole River. Rochester Creek originates in the northeast quadrant of section 13 and flows in a southeast direction to the south center edge of figure 10 and south and east of figure 10 joins the northeast oriented Big Hole River. Note in the northwest quadrant of section 13 a northwest-to-southeast oriented through valley (used by an unimproved road) linking the southeast oriented Rochester Creek headwaters valley with a northwest oriented (and barbed) Camp Creek tributary. The map contour interval for figure 10 is 40 feet and the through valley floor elevation at the drainage divide is between 6720 and 6760 feet. A hill in the northeast corner of section 15 (not labeled, but west of section 14) is shown with an elevation of 7386 feet while elevations on Big Ridge to the east rise much higher suggesting the through valley is at least 600 feet deep. Other slightly higher through valleys can be seen in sections 12 and 7 linking south oriented Rochester Creek headwaters valleys with northwest oriented and barbed Camp Creek tributary valleys. These multiple through valleys suggest diverging and converging southeast oriented flood flow channels such as might be found in a southeast oriented anastomosing channel complex once crossed the region. Headward erosion of the deep southwest oriented Camp Creek valley from the deep south-oriented Big Hole River valley beheaded and reversed each of the several southeast oriented flood flow channels. Floodwaters on the northwest ends of the beheaded flood flow channels reversed flow direction to erode the northwest oriented (and barbed) Camp Creek tributary valleys.

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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