Abstract:

This essay uses topographic map evidence to interpret landform origins in the region between Clear Creek and Crazy Woman Creek in the Wyoming Bighorn Mountains. Clear Creek headwaters originate in the high Bighorn Mountains and flow in southeast, east, and northeast directions to converge in a north to south oriented through valley along the Bighorn Mountains eastern flank and then to flow in a north-northeast and northeast direction to join the north oriented Powder River. Crazy Woman Creek headwaters originate in the high Bighorn Mountains south of the Clear Creek headwaters and flow in southeast, east, and northeast directions to also converge in the north to south oriented through valley along the Bighorn Mountains eastern flank and then to flow in a north-northeast and northeast direction to join the north oriented Powder River. Crazy Woman Creek headwaters are linked by through valleys with northeast oriented Clear Creek headwaters, south and southeast oriented North Fork Powder River headwaters, and with headwaters of southwest oriented streams flowing to north oriented Bighorn Basin rivers. Through valleys, elbows of capture, barbed tributaries, and valley orientations provide evidence the Clear Creek and Crazy Woman Creek drainage systems evolved as immense floods first flowed across the present day Clear Creek and Crazy Woman Creek drainage basins as the Bighorn Mountains began to emerge and later as the floodwaters were reversed to flow in north and northeast directions. Floodwaters were derived from the western margin of a thick North American ice sheet and were flowing from western Canada to and across the present day Bighorn Mountains and Powder River Basin. The Bighorn Mountains emerged as floodwaters flowed across them and as deep south-oriented flood flow channels eroded headward along the emerging mountain range eastern and western flanks. At the same time ice sheet related crustal warping raised the Bighorn Mountains, which are located along what is now the deeply eroded and warped southwest rim of the deep “hole” in which the huge ice sheet was located. The massive flood flow reversal occurred when headward erosion of the deep northeast oriented Yellowstone River valley beheaded south and southeast oriented flood flow routes crossing the Powder River Basin and the emerging Bighorn Mountains. The deep Yellowstone River valley eroded headward from space in the deep “hole” being opened up by ice sheet melting and which was initially drained in a south direction by flood flow channels east of the study area. Headward erosion of the deep Yellowstone River beheaded south and southeast oriented flood flow routes in sequence from east to west and floodwaters on north ends of beheaded flood flow channels reversed flow directions to create north oriented drainage systems. Northeast and north-northeast oriented valleys eroded headward from these newly created north oriented drainage systems to capture floodwaters still moving in a south direction west of actively eroding Yellowstone River valley head (and/or west of whatever actively eroding valley was to the north). Headward erosion of the north-northeast oriented Crazy Woman Creek valley first captured floodwaters flowing from the emerging Bighorn Mountains to a deep south-oriented flood flow channel along Bighorn Mountains eastern flank. Headward erosion of the north-northeast oriented Clear Creek valley next captured floodwaters flowing into that same south oriented flood flow channel along the Bighorn Mountains eastern flank. Similar captures occurred in the Clear Creek and Crazy Woman Creek headwaters areas, although those captures probably occurred before the reversal of flood flow in the Powder River Basin to the east.

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 Clear Creek-Crazy Woman Creek drainage divide area landform origins in the Wyoming Bighorn Mountains, 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 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 Clear Creek-Crazy Woman Creek drainage divide area landform evidence in the Wyoming Bighorn Mountains will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm.

Clear Creek-Crazy Woman Creek drainage divide area location map

Figure 1: Clear Creek-Crazy Woman 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 Clear Creek-Crazy Woman Creek drainage divide area in the Wyoming Bighorn Mountains and illustrates a region in north central Wyoming. The Montana-Wyoming state line is located near the north edge of figure 1. The Bighorn Mountains extend from the north edge of figure 1 (west half) to the south edge of figure 1 (west half). The Bighorn Basin is west of the Bighorn Mountains and the Powder River Basin is east of the Bighorn Mountains. The north oriented Bighorn River drains the Bighorn Basin and north of figure 1 flows to the northeast oriented Yellowstone River. The north oriented Powder River drains much of the Powder River Basin and also large areas in the southern Bighorn Mountains and north of figure 1 the Powder River flows to the northeast oriented Yellowstone River. The Tongue River drains areas in the Bighorn Mountains north of the Powder River tributaries and then flows in a northeast direction to the north edge of figure 1 (near Decker, Montana) and north of figure 1 joins the northeast oriented Yellowstone River. Clear Creek originates in the high Bighorn Mountains (south of Cloud Peak) and flows in an east direction to Buffalo, Wyoming where Clear Creek turns to flow in a northeast direction to join the Powder River. Crazy Woman Creek originates in the Bighorn Mountains (near Powder River Pass) and flows in a southeast, north-northeast, and northeast direction to join the Powder River. The Clear Creek-Crazy Woman Creek drainage divide area investigated in this essay is located south of Clear Creek, north of Crazy Woman Creek, and west of Interstate highway 25.

Today with exceptions south of Gillette, Wyoming all drainage routes seen in figure 1 eventually flow to the northeast oriented Yellowstone River north of figure 1. However, these north oriented drainage systems evolved during immense south and southeast melt water floods, which once crossed the entire region seen in figure 1. Floodwaters were derived from the western margin of a thick North American ice sheet and were flowing from western Canada to and across Wyoming. At least initially the Bighorn Mountains and other regional mountain ranges had not emerged and floodwaters were able to flow freely across what are today the high Bighorn Mountains. The Bighorn Mountains emerged as floodwaters deeply eroded surrounding regions while at the same time ice sheet related crustal warping raised the Bighorn Mountains and other regional mountain ranges. Ice sheet related crustal warping helped create a deep “hole” in which the massive ice sheet was located and the region seen in figure 1 could be considered a deeply eroded and warped segment of the deep “hole’s” southwest rim. Ice marginal melt water floods at first flowed in south and southeast along and across this deep “hole” southwest rim and the floodwaters began to erode deep south oriented flood flow channels on either side of the emerging Bighorn Mountains. Over time ice sheet melting began to open up space at the south end of the deep “hole”, which at first drained in south directions using flood flow channels east of figure 1. The deep northeast oriented Yellowstone River valley then eroded headward from this newly opened up space to capture the south and southeast oriented flood flow crossing the deep “hole’s” southwest rim. Headward erosion of the deep Yellowstone River valley beheaded south oriented flood flow channels crossing Wyoming in sequence from east to west. Flood flow channels to what was then the emerging Powder River Basin were beheaded first and floodwaters on the north ends of the beheaded flood flow channels reversed flow direction to create the north oriented Powder River drainage route. The newly reversed and much deeper north oriented Powder River drainage route then captured southeast oriented flood flow still crossing the emerging Bighorn Mountains, Headward erosion of the deep Yellowstone River valley next beheaded and reversed flood flow routes further to the west and in a similar manner created the north oriented Tongue River drainage system, which captured some of the flood flow moving to the newly created north oriented Powder River drainage system. This process was repeated when Yellowstone River valley headward erosion beheaded flood flow routes to the Bighorn Basin and created the north oriented Bighorn River drainage route and also ended all flood flow across the emerging Bighorn Mountains and Powder River Basin.

Detailed location map for Clear Creek-Crazy Woman Creek drainage divide area

Figure 2: Detailed location map Clear Creek-Crazy Woman Creek 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 Clear Creek-Crazy Woman Creek drainage divide area in the Wyoming Bighorn Mountains. The green colored areas are National Forest lands, which are located in the Bighorn Mountains. The Bighorn Mountains extend south of the green colored region, although most of the highest regions are included in the green colored areas.  The Powder River flows in a north direction along the east edge of figure 2. Cloud Peak is a labeled Bighorn Mountains high point located near the north edge of figure 2. Clear Creek is not labeled in figure 2, but originates south of Cloud Peak and flows in an east direction to Buffalo, Wyoming where Clear Creek turns to flow in a north-northeast direction to the north edge of figure 2 and north of figure 2 turns to flow in a northeast direction to join the Powder River. The unlabeled northeast oriented Clear Creek tributary in the Bighorn Mountains is South Clear Creek and the unlabeled north oriented South Clear Creek tributary is Sourdough Creek. Sand Creek (Bull Creek on more detailed maps) is a southeast, east, and north oriented Clear Creek tributary located south of Buffalo. Rock Creek is the southeast oriented tributary joining Clear Creek just east of Buffalo. Lake De Smet (near north center edge of figure 2) is located in a northwest to southeast oriented through valley linking a southeast oriented Piney Creek valley segment with the Rock Creek and Clear Creek valley. The North Fork Crazy Woman Creek originates in the Bighorn Mountains near the Sourdough Creek headwaters and flows in a northeast, southeast, and south direction to join the east oriented Middle Fork Crazy Woman Creek and then to join the northeast oriented South Fork Crazy Woman Creek and to form Crazy Woman Creek, which then flows in a northeast, north-northeast, and northeast direction to join the Powder River near the northeast corner of figure 2. Kirby Creek is a southeast and south-southeast oriented tributary to the North Fork Crazy Woman Creek and is located south and slightly west of Buffalo. Hazelton Peak is a labeled mountain near the south edge of the green colored area. The Middle Fork Crazy Woman Creek originates near Hazelton Peak and flows in a southeast and east direction to join the North and South Forks Crazy Woman Creek east of the Bighorn Mountains. The North Fork Powder River originates north and west of Hazelton Peak and flows in a south and southeast direction to the south edge of figure 2 (west of center) and south of figure 2 joins the Middle and South Forks of the Powder River to form the north oriented Powder River. Southeast and south oriented Crazy Woman Creek tributaries are located on alignments of southeast and south oriented flood flow channels that were captured by headward erosion of the much deep northeast and northeast oriented Crazy Woman Creek valley. Likewise the south and southeast oriented Powder River tributaries are located on alignments of south and southeast oriented flood flow channels captured by the flood flow reversals on what had been a south oriented flood flow channel on the present day north oriented Powder River alignment.

Clear Creek-Little North Fork Crazy Woman Creek drainage divide area east of Bighorn Mountains

Figure 3: Clear Creek-North Fork Little North Fork Crazy Woman Creek drainage divide area east of Bighorn Mountains. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 3 provides a topographic map of Clear Creek-Little North Fork Crazy Woman Creek drainage divide area and is located along the boundary between the Bighorn Mountains and the Powder River Basin. The map contour interval for figure 3 is 20 meters. Clear Creek flows in an east direction near the north edge of the northwest quadrant of figure 3 and just east of the north center edge turns to flow in a northeast direction to Buffalo, Wyoming (which is just north of figure 3). Elgin Park is located near the west center edge of figure 3. Grammund Creek originates west of Elgin Park and flows in a northeast and north direction to join Clear Creek between Grouse Mountain and Bald Ridge. Between the north oriented Grammund Creek valley and Bald Mountain are headwaters of southeast, east, and north oriented Bull Creek (sand Creek in figure 2), which flows to the north edge of figure 3 and north of figure 3 joins Clear Creek. A north to south oriented through valley west of Bald Ridge links the east oriented Clear Creek valley with the southeast oriented Bull Creek valley.  The through valley floor elevation is between 1820 and 1840 meters. Bald Ridge to the east rises to more than 2000 meters suggesting the through valley is at least 160 meters deep. South of Bald Ridge Bull Creek turns to flow in an east direction between Bald Ridge and Kingsbury Ridge in what could be considered to be a water gap. Little North Fork Crazy Woman Creek flows in a northeast direction from the west edge of figure 3 towards Elgin Park and then turns to flow in a southeast direction between Sisters Hill and Crazy Woman Mountain to the south center edge of figure 3 and south of figure 3 joins southeast and south-southeast oriented North Fork Crazy Woman Creek. West of Kingsbury Ridge is a through valley linking the southeast oriented Bull Creek headwaters valley with headwaters of south-southeast oriented Kelly Creek. And south of figure 3 Kelly Creek joins the Little North Fork Crazy Woman Creek. The through valley west of Kingsbury Ridge links the Bull Creek valley (and Clear Creek valley) with the southeast and south oriented North Fork Crazy Woman Creek valley. The through valley floor elevation is between 1700 and 1720 meters. Kingsbury Ridge, which is a hogback ridge, rises to at least 1840 meters suggesting the through valley is at least 120 meters deep. The highway east of Kingsbury Ridge makes use of a much broader, but (perhaps) shallower north to south oriented through valley. These through valleys along the Bighorn Mountains east flank were eroded as south oriented flood flow channels prior to the flood flow reversal that created the north oriented Powder River drainage system. When the flood flow reversal took place the north-northeast oriented Crazy Woman Creek eroded headward to capture the south oriented flood flow channels seen in figure 1 first. Next headward erosion of the northeast and northeast oriented Clear Creek valley captured the south and southeast oriented flood flow and beheaded the flood flow routes to the newly eroded Crazy Woman Creek valley. Floodwaters on north ends of beheaded flood flow reversed flow direction to create north oriented Clear Creek tributary drainage routes. The north oriented Bull Creek segment was created by a reversal of flood flow and captured flood flow moving in a south direction west of the actively eroding east oriented Clear Creek valley head. The captured flood flow then created the southeast and east oriented Bull Creek segments and beheaded south oriented flood flow to the Kelly Creek valley. Headward erosion of the deeper east oriented Clear Creek valley then beheaded the south oriented flood flow west of Bald Ridge ending flood flow to the Bull Creek headwaters valley. Next Clear Creek valley headward beheaded and reversed a south oriented flood flow channel on the Grammund Creek alignment. A northeast oriented valley then eroded headed from the newly reversed flood flow channel to capture flood flow moving in a south direction west of the actively eroding Clear Creek valley head.

Detailed map of Bull Creek-Kelly Creek drainage divide area

Figure 4: Detailed map of Bull Creek-Kelly 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 Bull Creek-Kelly Creek drainage divide area seen in less detail in figure 3. The map contour interval for figure 4 is 40 feet. Bull Creek (labeled “Creek” in figure 4) flows in an east-southeast and east direction from the north center edge of figure 4 to near the northeast corner of figure 4 and east of figure 4 turns to flow in a north direction to north-northeast oriented Clear Creek. North of the figure 4 Bull Creek flows in a southeast direction to the north center edge of figure 4 (see figure 3). Kelly Creek flows from the west center edge of figure 4 in an east, southeast, and south-southeast direction to the south edge of figure 4 (east half), and south of figure 4 Kelly Creek flows to south-southeast oriented Little North Fork Crazy Woman Creek, which then flows to south-southeast oriented North Fork Crazy Woman Creek. Kingsbury Ridge is located in the east half of figure 4 and rises to more than 6080 feet. The Klondike Road in section 31 makes use of a north to south oriented through valley linking the Bull Creek valley with the south-southeast oriented Kelly Creek valley. The through valley floor elevation at the lowest point on the drainage divide has an elevation of between 5580 and 5600 feet. The Bighorn Mountains to the west of figure 4 rise to elevations much higher than the Kingsbury Ridge elevation, which means the through valley is at least 480 feet deep. This through valley is an example of the south and southeast oriented flood flow channels that eroded headward into the Powder River Basin as the floodwaters deeply eroded regions surrounding the emerging Bighorn Mountains. Floodwaters were flowing across the Bighorn Mountains to reach these south and southeast oriented flood flow channels, which suggests areas north and west of Bighorn Mountains had not yet been deeply eroded and that Bighorn Mountains uplift and/or emergence was still underway when headward erosion of the deep north-northeast and northeast oriented Clear Creek valley and its newly beheaded and reversed Bull Creek tributary valley (north and east of figure 4) captured the south oriented flood flow west of Kingsbury Ridge and diverted the flood flow in an east and north direction to the newly eroded north-northeast and northeast oriented Clear Creek valley and then to the newly created north oriented Powder River valley with the floodwaters eventually flowing to space in the deep “hole” the melting ice sheet had opened up. Probably at that time floodwaters were draining from the south end of the deep “hole” in a south direction using south oriented flood flow channels east of the region studied in this essay.

Sourdough Creek-North Fork Crazy Woman Creek drainage divide area

Figure 5: Sourdough Creek–North Fork Crazy Woman Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 5 illustrates the Sourdough Creek-North Fork Crazy Woman Creek drainage divide area west and slightly south of figure 3 and there is an overlap area with figure 3. The map contour interval for figure 5 is 20 meters. Sisters Hill and Crazy Woman Mountain are located near the east edge of figure 5. Remember from figure 3 the through valley elevation just east of figure 5 was less than 1700 meters. To illustrate the change in elevation west of that through valley Darton Peak in the northwest corner of figure 5 rises to 3741 meters or more than 2000 meters above the through valley floor. Loaf Mountain in the west center area of figure 5 rises to 3573 meters. South and slightly east of Loaf Mountain are southeast oriented headwaters of the North Fork Crazy Woman Creek, which flows to the south center edge area of figure 5 and then turns to flow in a northeast and east-northeast direction to the east edge of figure 5 (south of Crazy Woman Mountain). East of figure 5 North Fork Crazy Woman Creek turns to flow in a southeast and south direction to join north-northeast oriented Crazy Woman Creek. Little North Fork Crazy Woman Creek originates near the highway in the east center area of figure 5 and flows in a northeast and southeast direction to the east edge of figure 5 (between Sisters Hill and Crazy Woman Peak) and east of figure 5 flows in a south-southeast direction to join the North Fork Crazy Woman Creek. Other North Fork Crazy Woman Creek tributaries seen in figure 5 include east and south-southeast oriented Merle Creek, east-southeast oriented Caribou Creek, and east, northeast, southeast, and south oriented Pole Creek, which originates north of Sheep Mountain. South Clear Creek originates in the Chill Lakes region between Darton Peak and Bighorn Peak near the northwest corner of figure 5 and flows in an east-southeast and northeast direction to the north edge of figure 5 (east of center). Duck Creek originates at Paradise Lake near Loaf Mountain and flows in a northeast direction to join South Clear Creek. Sourdough Creek originates east of Loaf Mountain and flows in an east-northeast, northeast, and north direction to join South Clear Creek near the north edge of figure 5. Little Sourdough Creek is east of Sourdough Creek and flows in a north-northeast and north direction and joins Sourdough Creek near the north edge of figure 5. West oriented streams just barely seen along the west edge of figure 5 flow to southwest oriented Tensleep Creek, which joins the northwest oriented Nowood River, which in turn flows to the north oriented Bighorn River in the Bighorn Basin. The number of southeast oriented streams in what is today a north oriented drainage basin suggests south and southeast oriented flood flow was captured by east and northeast oriented valleys that were eroding headward into an emerging Bighorn Mountains mass. Shallow through valleys cross some of the drainage divides and provide further evidence of former southeast oriented flood flow channels. For example, near the center of figure 5 a northwest to southeast oriented through valley links the Sourdough Creek valley with the Pole Creek valley. The through valley floor elevation is between 2680 and 2700 meters. Elevations along the drainage divide to the northeast rise to more than 2740 meters suggesting the through valley is at least 40 meters deep. While not deep when compared with the mountains to the west the through valley is evidence of a southeast oriented drainage route that existed prior to headward erosion of the northeast oriented Sourdough Creek valley. Perhaps even more intriguing is the through valley south of Loaf Mountain linking a west oriented Tensleep Creek tributary valley with the southeast oriented North Fork Crazy Woman Creek valley. The floor of this second through valley has an elevation of between 3060 and 3080 meters. The high point south of the through valley rises to 3198 meters suggesting the through valley is approximately 120 meters deep, if not deeper. This second through valley provides evidence that southeast oriented floodwaters crossed what is now the Bighorn River-Powder River drainage divide and helped erode the North Fork Crazy Woman Creek valley. Powder River Pass seen near the southwest corner of figure 5 is illustrated and discussed in figures 7 and 8 below.

Detailed map of Sourdough Creek-Pole Creek drainage divide area

Figure 6: Detailed map of Sourdough Creek-Pole 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 Sourdough Creek-Pole Creek drainage divide area seen in less detail in figure 5. The map contour interval for figure 6 is 40 feet. Sourdough Creek flows in an east-northeast and northeast direction from the west edge of figure 6 (south of center) to the north center edge of figure 6 and north of figure 6 joins South Clear Creek. Pole Creek originates near the southwest corner of figure 6 and flows in an east-northeast direction into section 22 where Pole Creek turns to flow in a southeast direction to the southeast corner of figure 6. Follow the drainage divide between Sourdough Creek and Pole Creek and there are several northwest to southeast oriented through valleys crossing the divide. Some the through valleys are shallow and are defined by only one or two contour lines on a side. The deepest through valley is located in the southwest corner of section 16 and has floor elevation of between 8800 and 8840 feet. The high point near the west center edge of section 16 reaches 9065 feet suggesting the through valley is more than 125 feet deep. This through valley and the other shallower through valleys were eroded as diverging and converging southeast oriented flood flow channels and were flowing to what at that time was the actively eroding southeast oriented Pole Creek valley. The east-northeast Pole Creek headwaters valley eroded headward from the southeast oriented Pole Creek valley segment. Headward erosion of the deep northeast oriented North Fork Crazy Woman Creek valley segment (south and east of figure 6-see figure 5) first captured the southeast oriented flood flow. Headward erosion of the northeast oriented Sourdough Creek valley next captured the southeast oriented flood flow and diverted the floodwaters to the northeast oriented South Clear Creek valley. The capture events seen in figure 6 illustrate capture events that can be reconstructed on a regional basis. Each change of direction made by a valley today records a capture event and each through valley across a modern-day drainage divide records a beheaded flood flow channel. The history of captures in the Bighorn Mountains is complex, but hopefully this illustration and brief discussion provides a brief outline of some of the major flood flow movements.

North Fork Crazy Woman Creek-North Fork Powder River drainage divide area

Figure 7: North Fork Crazy Woman Creek-North Fork Powder River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 7 illustrates the North Fork Crazy Woman Creek-North Fork Powder River drainage divide area south and west of figure 5 and includes an overlap area with figure 5. The map contour interval for figure 7 is 20 meters. Powder River Pass is located near the center of figure 7 and Munkres Pass is located east of Powder River Pass. The North Fork Crazy Woman Creek originates north of Munkres Pass and flows in a southeast and northeast direction to the east edge of figure 7 (north half). Muddy Creek originates at Munkres Pass and flows roughly parallel to North Fork Crazy Woman Creek on the south side of the highway to the east edge of figure 7 and east of figure 7 turns to flow in a southeast and south-southeast direction to join the south North Fork Crazy Woman Creek segment along the Bighorn Mountains east flank. The North Fork Powder River originates a short distance south of Powder River Pass and flows in a south-southwest direction to the south edge of figure 7 (west of center) south of figure 7 the North Fork Powder River turns to flow in a southeast direction to join other Powder River tributaries and to form the north and northeast oriented Powder River. West of Powder River Pass are headwaters of southwest and south-southwest oriented Canyon Creek (“Creek” in figure 7), which flows to the south edge of figure 7 (near southwest corner) and which south of figure 7 turns to flow in a west and northwest direction to join southwest oriented Tensleep Creek. Southwest oriented Tensleep Creek flows across the northwest corner of figure 7 and west of figure 7 joins the north and northwest oriented Nowood River, which then flows to the north-oriented Bighorn River. Baby Wagon Creek is a west oriented Tenseep Creek tributary in the northwest quadrant of figure 7. Powder River Pass is shown as having an elevation of 2851 meters. Hazelton is a small town in the southeast quadrant of figure 7. The southeast oriented stream flowing from Hazelton to the southeast corner of figure 7 is the Middle Fork Crazy Woman Creek, which south and east of figure 7 turns to flow in an east direction to join south oriented North Fork Crazy Woman and north-northeast oriented South Fork Crazy Woman Creek to form northeast and north-northeast oriented Crazy Woman Creek. Hesse Mountain to the southeast of Powder River Pass rises to 3165 meters while the unnamed mountain to the northwest rises to 3198 meters. These elevations suggest Powder River Pass may as much as 300 meters deep. Today Powder River Pass and Munkres Pass link the east and south oriented North Fork Crazy Woman Creek and Muddy Creek valleys with the south-southwest oriented North Fork Powder River and Canyon Creek valleys. However a look at the north to south oriented divide between Powder River tributaries on the east and Bighorn River tributaries on the west shows numerous other through valleys crossing the drainage divide. These through valleys provide evidence that multiple east and southeast oriented flood flow channels once crossed what is now the high Bighorn Mountains crest ridge. At the time floodwaters crossed the region elevations west of the present day drainage divide were comparable to or greater than elevations of the through valley floors. Floodwaters crossing the present day Bighorn Mountains drainage divide were flowing to the much deeper south oriented flood flow channels located along the emerging Bighorn Mountains eastern front. The east and southeast oriented flood flow channels were later beheaded by headward erosion of deeper south oriented flood flow channels west of the present day drainage divide. Reversals of flood flow in the Powder River basin probably occurred later and reversals of flood flow in the Bighorn Basin occurred even later. As these flood flow events occurred the Bighorn Mountains were emerging to become the high mountain range they are today.

Detailed map of North Fork Crazy Woman Creek-North Fork Powder River drainage divide area

Figure 8: Detailed map of North Fork Crazy Woman Creek-North Fork Powder River 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 North Fork Crazy Woman Creek-North Fork Powder River drainage divide area seen in less detail in figure 7 above. The map contour interval for figure 8 is 40 feet. The North Fork Crazy Woman Creek flows in a southeast and east direction from the north edge of figure 8 (east of center) to the east edge of figure 8 (north half). Munkres Pass is located south of the center of figure 8. Muddy Creek originates in section 11 east of Munkres Pass and flows in an east-northeast and east direction to the east center edge of figure 8. Hesse Creek originates in section 1 and flows in an east-southeast direction between the North Fork Crazy Woman Creek and Muddy Creek to the east edge of figure 8 (north of center) and east of figure 8 eventually joins the North Fork Crazy Woman Creek. The North Fork Powder River originates in section 10 west of Munkres Pass and flows in south-southwest direction to the south edge of figure 8 (west half). Munkres Pass has an elevation of 9447 feet and the North Fork Crazy Woman Creek-North Fork Powder River drainage divide near the north edge of section 10 has an elevation of 9355 feet. Hesse Mountain in section 14 rises to 10,385 feet and an elevation of 10,493 feet is located just north of figure 4 (north of Powder River Pass). These elevations suggest the through valleys linking the south-southwest oriented North Powder River valley with the east oriented North Fork Crazy Woman Creek valley and tributary valleys are approximately 1000 feet deep. These through valleys were initially eroded by east oriented floodwaters probably flowing along the south margin of what at that time were the emerging Bighorn Mountains to deeper south oriented flood flow channels east of the emerging Bighorn Mountains. These east oriented flood flow channels were then beheaded by headward erosion of the south-southwest oriented North Fork Powder River valley and subsequently by headward erosion of the south-southwest oriented Canyon Creek valley. Still later headward erosion of the southwest oriented Tensleep Creek valley beheaded all flood flow to the region and diverted floodwaters to south oriented flood flow channels eroding headward along the west side of the emerging Bighorn Mountains. Reversals of flood flow in the Powder River Basin to the east and in the Bighorn Basin to the west probably occurred after all flood flow across this southern Bighorn Mountains region had ended.

North Fork Crazy Woman Creek-Middle Fork Crazy Woman Creek drainage divide area

Figure 9: North Fork Crazy Woman Creek-Middle Fork Crazy Woman Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 9 illustrates the North Fork Crazy Woman Creek-Middle Fork Crazy Woman Creek drainage divide area east and slightly south of figure 7 and includes an overlap area with figure 7. The map contour interval for figure 9 is 20 meters. The North Fork Crazy Woman Creek flows in an east-southeast and northeast direction across the northwest corner of figure 9 and north and east of figure 9 turns to flow in a south-southeast and south direction. Just south of the North Fork Crazy Woman Creek Hesse Creek flows in an east direction from the west edge of figure 9 to join the North Fork. Immediately south of Hesse Creek Muddy Creek flows in an east and east-northeast direction from the west edge of figure 9 to near the north edge of the northeast quadrant of figure 9 and then turns to flow in a southeast direction to the east edge of figure 9 (north half) and east of figure 9 joins south oriented North Fork Crazy Woman Creek. Billy Creek is an east oriented tributary flowing to the east edge of figure 9 (north of center) and joins south oriented North Fork Crazy Woman Creek east of figure 9. The Middle Fork Crazy Woman Creek flows in a southeast direction from the west center edge of figure 9 to Hazelton and then to Robinson Canyon where the Middle Fork turns to flow in an east direction to the east edge of figure 9. East of figure 9 the Middle Fork joins the south oriented North Fork and north-northeast oriented South Fork to form north-northeast oriented Crazy Woman Creek. Poison Creek flows from the west edge of figure 9 (north half) in a southeast direction to join Middle Fork Crazy Woman Creek near the east end of Robinson Canyon (the Poison Creek north of Middle Fork Crazy Woman Creek flowing to the east edge of figure 9 (south half) is a different Poison Creek and is a tributary to south oriented North Fork Crazy Woman Creek). Note in the region north and west of Robinson Canyon numerous streamlined residuals with a maze of through valleys between them  (Bald Hill is at the west end of this region). Some of the through valleys are defined by as many as six contour lines on a side and are at least 100 meters deep. These streamlined residuals are probably hogbacks along the Bighorn Mountains eastern flank, although the through valleys are water-eroded valleys and provide evidence of what was once an anastomosing complex of channels flowing to what was at that time the actively eroding Middle Fork Crazy Woman Creek valley. Headward erosion of the Poison Creek valley captured the south and southeast flood flow and ended southeast oriented flood flow across the that segment of the Poison Creek-Middle Fork Crazy Woman Creek drainage divide. Headward erosion of the Middle Fork Crazy Woman Creek and Poison Creek valleys probably occurred from a deep south oriented flood flow channel east of the emerging Bighorn Mountains eastern flank and occurred before headward erosion of the north-northeast oriented Crazy Woman Creek valley captured that south oriented flood flow channel and diverted the floodwaters in a north-northeast direction to space in the deep “hole” the melting ice sheet was opening up.

Detailed map of Poison Creek-Middle Fork Crazy Woman Creek drainage divide area

Figure 10: Detailed map of Poison Creek-Middle Fork Crazy Woman 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 Poison Creek-Middle Fork Crazy Woman Creek drainage divide area seen in less detail in figure 9. The map contour interval for figure 10 is 40 feet. Hazelton is the small town located in the southwest quadrant of figure 10. Middle Fork Crazy Woman Creek flows in a southeast direction from the west edge figure 10 (just north of center) to the south edge of figure 10 (east of center). Poison Creek flows in an east-southeast direction from the north edge of figure 10 (west half) to the east edge of figure 10 (north half) and east and south of figure 10 (and at a much lower elevation) joins the Middle Fork Crazy Woman Creek. The streamlined hill in section 35 in the southeast corner of figure 10 is Bald Hill (the name does not show in figure 10). The high point on Bald Hill (not shown in figure 10) is 8275 feet. In the northwest quadrant of section 35 a through valley links the headwaters of an east oriented Poison Creek tributary with a south oriented Middle Fork Crazy Woman Creek tributary. The through valley flow elevation is between 7880 and 7920 feet. Elevations near the west edge of figure 10 rise much higher than 8300 feet indicating the through valley is at least 355 feet deep. But, the through valley is just a deep channel eroded into the floor of a much broader through valley extending west of Bald Hill to near the west edge of figure 10. The entire Poison Creek-Middle Fork Crazy Woman Creek drainage divide area between west edge area of figure 10 and Bald Hill is lower than the top of Bald Hill and prior to headward erosion of the east-southeast oriented Poison Creek valley was crossed by southeast oriented flood flow moving to what at that time was the actively eroding southeast and east oriented Middle Fork Crazy Woman Creek valley (or Robinson Canyon, seen in figure 9). Headward erosion of the Poison Creek valley captured much of the flood flow and ended flood flow across the drainage divide in the region seen in figure 10. Subsequently headward erosion of the North Fork Crazy Woman Creek valley to the region north of Munkres Pass seen in figures 7 and 8 ended all flood flow to the Middle Fork Crazy Woman Creek valley before the deep Robinson Canyon could erode headward into the region seen in figure 10.

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.