Abstract:

This essay uses topographic map evidence to interpret landform origins in the region between the Lamar River drainage basin and the Clarks Fork Yellowstone River drainage basin in the Absaroka Range along the Yellowstone National Park eastern boundary, Wyoming and Montana. The Lamar River flows in a west and northwest direction in Yellowstone National Park to join the north and northwest oriented Yellowstone River, which north of Yellowstone National Park turns to flow in an east and northeast direction across Montana. Clarks Fork originates near the Yellowstone National Park northeast corner and flows in a southeast direction before turning to flow in a north-northeast direction to join the northeast oriented Yellowstone River. A through valley or high mountain pass links headwaters of a west and southwest oriented Lamar River tributary with southeast oriented Clarks Fork headwaters. Further south higher elevation notches, gaps, or passes cross the Lamar River-Clarks Fork drainage divide and link Lamar River tributary valleys with Clarks Fork tributary valleys and also cross drainage divides between the various Lamar River and Clarks Fork tributaries. The through valleys, notches, gaps, and passes are interpreted to have been eroded by south and southeast oriented flood flow channels that once crossed the Absaroka Range region. Floodwaters were derived from the western margin of a melting thick North American ice sheet and were flowing from western Canada across Montana into and across Wyoming. At that time the Absaroka Mountains did not stand high above regions to the north and were not a topographic barrier to the south and southeast oriented flood flow. Absaroka Range uplift occurred as floodwaters flowed across the region and as the deep southeast oriented Clarks Fork valley and tributary valleys eroded headward from south oriented flood flow channels in the present day north oriented Big Horn Basin and as southwest oriented tributaries eroded headward from southeast and south oriented flood flow channels in the present day Yellowstone National Park region. Headward erosion of the deep northeast oriented Yellowstone River in eastern Montana from space in the deep “hole” the melting ice sheet had occupied and which was being opened up by the ice sheet melting first beheaded and reversed south oriented flood flow routes in the Big Horn Basin, which among other things created the north-northeast oriented Clarks Fork drainage route, which then captured the southeast oriented Clarks Fork flood flow channel. Subsequently headward erosion of the deep east oriented Yellowstone River valley across southern Montana beheaded and reversed south and southeast oriented flood flow channels to the Yellowstone National Park region and created the Yellowstone National Park north and northwest oriented Yellowstone River drainage system. The massive flood flow reversals were greatly aided by ice sheet related crustal warping that raised mountain ranges and plateau areas, including the Absaroka Range and the Yellowstone Plateau, as floodwaters flowed across them.

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 Lamar River-Clarks Fork Yellowstone River drainage divide area landform origins along the Yellowstone National Park eastern boundary. 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 Lamar River-Clarks Fork Yellowstone River drainage divide area landform evidence along the Yellowstone National Park eastern boundary will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm.

Lamar River-Clarks Fork Yellowstone River drainage divide area location map

Figure 1: Lamar River-Clarks Fork Yellowstone 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 Lamar River-Clarks Fork Yellowstone River drainage divide along the Yellowstone National Park eastern boundary and shows a region in northern Wyoming in the south half and a region in southern Montana in the north half. Yellowstone National Park is located in the northwest corner of Wyoming and is labeled in figure 1. The Yellowstone River flows in a north-northwest direction to Yellowstone Lake and then in a northwest direction to Canyon, Wyoming. From Canyon the Yellowstone River flows in a northeast, north, and northwest direction to Gardiner, Montana and then in a northwest, north-northeast direction, and east-northeast direction to Big Timber, Montana. From Big Timber the Yellowstone River flows in an east-southeast and east-northeast direction to Billings, Custer, and the north edge of figure 1. North and east of figure 1 the Yellowstone River flows in a northeast direction to join the Missouri River. The Lamar River is a northwest oriented Yellowstone River tributary located in the northeast quadrant of Yellowstone National Park. The Clarks Fork Yellowstone River originates near Cooke City, Montana (near northeast corner of Yellowstone National Park) and flows in a southeast direction until it is joined by east and northeast oriented Sunlight Creek and then turns to flow in a northeast and north-northeast direction to join the Yellowstone River near Laurel, Montana. The Lamar River-Clarks Fork Yellowstone River drainage divide area along the Yellowstone National Park eastern boundary investigated here extends southward from the Cooke City, Montana area to the headwaters of the west and northwest oriented Lamar River and of east and northeast oriented Sunlight Creek and is located along the crest of the high Absaroka Mountains.

The Yellowstone National Park boundary in this region is defined by the Lamar River-Clarks Fork Yellowstone River drainage divide and is located between major valleys both to the east and to the west. To the east a major north-to-south oriented through valley or lowland is located between the Absaroka Range and the Pryor Mountains in which the highway from Laurel, Mountain to Cody, Wyoming is located. Today the north end of that through valley is drained by the north-northeast oriented Clark Fork Yellowstone River while the east-northeast, north, and northeast oriented Shoshone River drains the through valley in the Cody area. The through valley was eroded by massive south and southeast oriented melt water floods prior to headward erosion of the deep northeast oriented Yellowstone River valley. Floodwaters were derived from the western margin of a melting thick North American ice sheet and were flowing in south and southeast directions from western Canada to and across the figure 1 map area. The ice sheet had created a deep “hole” in which it was located by deep glacial erosion of the surface underneath the ice sheet and by crustal warping that raised mountain ranges and plateau areas elsewhere on the continent. The Absaroka Range and other mountain ranges seen in figure 1 were uplifted as melt water floods flowed across them. The deep northeast oriented Yellowstone River valley eroded headward from space in the deep “hole” being opened up by the ice sheet melting and captured the southeast and south oriented melt water floods and diverted the floodwaters into space in the deep “hole” the ice sheet had once occupied. Floodwaters on north ends of beheaded flood flow channels reversed flow direction to create north oriented drainage routes. In the case of the Clarks Fork Yellowstone River southeast oriented flood flow from west of the deep northeast oriented Yellowstone River valley continued to flow along what is today the Absaroka Mountains crest and eroded the deep southeast oriented Clarks Fork canyon headward from the reversed flood flow channel that created the north-northeast oriented Clarks Fork Yellowstone River drainage route.

West of the Absaroka Range a major south and southeast oriented flood flow channel developed along the alignment of the present day north and northwest oriented Yellowstone River. Headward erosion of the much deeper Yellowstone River across southern Montana eventually beheaded and reversed all south oriented flood flow channels to the southeast oriented Clarks Fork Yellowstone River headwaters and then beheaded and reversed the south and southeast oriented flood flow channel on the present day north and northwest oriented Yellowstone River alignment. This reversal of flood flow created the north and northwest oriented Yellowstone River drainage system in Yellowstone National Park. The present day northwest oriented Lamar River valley originated as a southeast oriented flood flow channel diverging from the south and southeast oriented flood flow channel on the present day north and northwest oriented Yellowstone River alignment. The reversal of flood flow in the Yellowstone River flood flow channel also reversed flood flow in the Lamar River valley to create the northwest oriented Lamar River drainage route seen today. While this brief description makes these flood flow reversals sound simple they actually were complex. Flood flow channels were beheaded one at a time and usually from east to west. Reversed flood flow in a newly beheaded flood flow channels often captured yet to be reversed south oriented flood flow from adjacent flood flow channels. Further, ice sheet related crustal warping was raising mountain ranges and plateau areas as floodwaters flowed across them. Uplift of the Absaroka Range and of the Yellowstone Plateau played major roles in the flood flow reversals that created the north oriented Yellowstone River drainage system in Yellowstone National Park and other north oriented drainage routes seen in figure 1.

Detailed location map for Lamar River-Clarks Fork Yellowstone River drainage divide area

Figure 2: Detailed location map Lamar River-Clarks Fork Yellowstone 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 Lamar River-Clarks Fork Yellowstone River drainage divide area along the Yellowstone National Park eastern boundary. Yellowstone National Park is shown in the red-brown color in the west half of figure 2 and the North Absaroka Wilderness is east of the Yellowstone National Park eastern boundary. The Montana-Wyoming state line is the west-to-east line in the north half of figure 2. The Lamar River originates near the easternmost point in Yellowstone National Park and flows in a north, west, and southwest direction before turning to flow in a north-northwest and northwest direction to the west edge of figure 2. West of figure 2 the Lamar River joins the northwest oriented Yellowstone River, which eventually turns to flow in a northeast, east-southeast, and northeast direction north of figure 2. Major Lamar River tributaries include west-southwest and south-southwest oriented Soda Butte Creek, which originates near Cooke City, Montana; south-southwest oriented and west oriented Cache Creek; southwest and west oriented Calfee Creek, and west oriented Miller Creek. Clarks Fork Yellowstone River originates near Cooke City, Montana and flows in a southeast, east, and southeast direction before turning to flow in a northeast, east, and north-northeast direction to the northeast corner of figure 2. Crandall Creek is an important east-northeast oriented tributary and has tributaries originating just east of the Yellowstone National Park eastern boundary. These tributaries include the southeast oriented North Fork, east-southeast oriented Closed Creek, east oriented Timber Creek, northeast-oriented Papoose Creek, and north-northeast oriented Hoodoo Creek. Sunlight Creek originates south of the Lamar River headwaters and flows in a south, east, and northeast direction to join the Clark Fork Yellowstone River at the point where the Clark Fork turns from flowing in a southeast direction to flowing in a northeast direction. Note the large number of south oriented drainage routes or south oriented drainage route segments in what are today north oriented drainage basins. These south oriented valleys are relics of south oriented flood flow channels that once crossed the region and which were captured by headward erosion of deeper flood flow channels, which were subsequently beheaded and reversed to form the north oriented drainage basins seen today. The flood flow captures occurred as crustal warping was raising the Absaroka Range and the flood flow reversals occurred when headward erosion of the much deeper Yellowstone River valley north of figure 2 beheaded the south oriented flood flow channels in sequence from east to west. Uplift of the Absaroka Range and of the Yellowstone Plateau greatly aided in the flood flow reversals.

Soda Butte Creek-Clarks Fork Yellowstone River drainage divide area

Figure 3: Soda Butte Creek-Clarks Fork Yellowstone River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 3 provides a topographic map of the Soda Butte Creek-Clarks Fork Yellowstone River drainage divide area. The Yellowstone National Park boundary is shown with a dashed line extending in a northeast direction from the west edge of figure 3 to Wolverine Peak and then in a south direction to Amphitheater Mountain before turning in an east and south-southeast direction to the south center edge of figure 3. Soda Butte Creek originates near Cooke City and flows in a west-southwest and south-southwest direction to near the southwest corner of figure 3. South and west of figure 3 Soda Butte Creek joins the northwest oriented Lamar River. Clarks Fork Yellowstone River is formed at the confluence of south oriented Lady of the Lake Creek and southeast oriented Fisher Creek north of Colter Pass and flows in a south-southeast and southeast direction to near the southeast corner of figure 3. South and east of figure 3 Clarks Fork Yellowstone River turns to flow in a north-northeast direction to join the northeast oriented Yellowstone River. Colter Pass is east of Cooke City and is a through valley linking the west-southwest oriented Soda Butte Creek valley with the south-southeast oriented Clarks Fork Yellowstone River valley. The map contour interval for figure 3 is 50 meters and the Colter Pass elevation at the drainage divide is between 2450 and 2500 meters. Mountains north of Colter Pass rise to elevations greater than 3200 meters as do mountains south of Colter Pass suggesting the through valley is at least 700 meters deep. The through valley is a water-eroded feature and was eroded by southeast and east oriented flood flow moving to an actively eroding south-southeast and southeast oriented Clarks Fork Yellowstone River valley. Headward erosion of a deep south-southwest oriented flood flow channel on the Soda Butte Creek alignment captured some of the flood flow and became a diverging flood flow channel. At that time the Absaroka Range did not stand high above surrounding regions and floodwaters were eroding flood flow channels into a surface equivalent in elevation to the tops of the highest mountain peaks in figure 3 today. Uplift of the Absaroka Range combined with headward erosion of the deep Yellowstone River valley (north of figure 3) ended south and southeast oriented flood flow across the region and created the Soda Butte Creek-Clarks Fork Yellowstone River drainage divide.

Detailed map of Soda Butte Creek-Clarks Fork Yellowstone River drainage divide area

Figure 4: Detailed map of Soda Butte Creek-Clarks Fork Yellowstone River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 4 uses a detailed topographic map to illustrate the Soda Butte Creek-Clarks Fork Yellowstone River drainage divide area seen in less detail in figure 3. Cooke City, Montana is the town straddling the west edge of figure 4. Soda Butte Creek originates in the northeast corner of section 30 and flows in a west-southwest direction to Cooke City and the west edge of figure 4. West of figure 4 Soda Butte Creek turns to flow in a south-southwest direction to join the northwest oriented Lamar River. Miller Creek is the southeast oriented stream joining Soda Butte Creek as a barbed tributary just east of Cooke City. Clarks Fork Yellowstone River flows in a south-southeast direction from the north edge of figure 4 (east of center) to the southeast corner of section 29 and into section 28 where it is joined by Forage Creek and the Broadwater River and then flows to the east edge of figure 4 (south half). East of figure 4 Clarks Fork Yellowstone River flows in a southeast direction in a deep canyon for a considerable distance before turning to flow in a northeast and north-northeast direction to join the Yellowstone River. Colter Pass is labeled and is located on the boundary between sections 20 and 29 and links the west-southwest oriented Soda Butte Creek valley with the south-southeast and southeast oriented Clarks Fork Yellowstone River valley. The map contour for figure 4 is 40 feet and the Colter Pass elevation at the drainage divide is between 8000 and 8040 feet. Elevations on the mountain to the south reach more than 10,400 feet (just south of figure 4) and mountains north of figure 4 also reach elevations greater than 10,400 feet suggesting Colter Pass may be as much as 2400 feet deep. Colter Pass is a water-eroded valley and was eroded by southeast oriented flood flow moving to the southeast oriented Clarks Fork Yellowstone River valley. Headward erosion of the deeper south-southwest and west-southwest oriented Soda Butte Creek valley from a south oriented flood flow channel on the present day northwest oriented Lamar River alignment captured some of the southeast oriented flood flow and created the Colter Pass drainage divide. Significant regional uplift combined with headward erosion of the much deeper Yellowstone River valley (north of figure 4) ended all flood flow across the region.

Cache Creek-North Fork Crandall Creek drainage divide area

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

Figure 5 illustrates the Cache Creek-North Fork Crandall Creek drainage divide area south of figure 3 and includes an overlap area with figure 3. Soda Butte Creek flows in a west and south-southwest direction from the north edge of figure 5 (west half) to the west edge of figure 5 (south of center) and west and south of figure 5 joins the northwest oriented Lamar River. Clarks Fork Yellowstone River flows in a southeast direction from the north edge of figure 5 (east half) to the east edge of figure 5 (north of center). Republic Pass is a labeled location north of the center of figure 5. Pilot Creek is the east-northeast oriented tributary flowing from near Republic Pass to join Clarks Fork near the east edge of figure 5. The North Fork Crandall Creek flows to the east edge of figure 5 (near southeast corner). Republic Creek originates north of Republic Pass and flows in a north-northeast direction to join west-southwest and south-southwest oriented Soda Butte Creek north of figure 5. Cache Creek originates west of Republic Pass and flows in a west and south-southwest direction to the south edge of figure 5 (near southwest corner) and south of figure 5 joins the northwest oriented Lamar River. Republic Pass is a mountain pass crossing a high mountain ridge and has an elevation of between 3000 to 3050 meters (the map contour interval for figure 5 is 50 meters). To the southeast the ridge rises to 3287 meters and to the northwest the ridge rises to 3179 meters. Pilot Peak to the northeast rises to 3569 meters and Ablattar Peak to the northwest rises to 3371 meters. Depending on which elevations are used Republic Pass could be considered to be anywhere from 129 meters to more than 200 meters deep. Standing at Republic Pass today offers views down five deep valleys diverging in different directions, yet Republic Pass is what remains of what was once a water-eroded valley. At that time the deep valleys radiating in different directions did not exist and south oriented flood flow was carving a deep valley into a surface as high, if not higher, than the tops of the high peaks seen in figure 5. Also at that time the Absaroka Range did not stand high above surrounding regions as it does today, but it may have been beginning to emerge as a mountain range. Floodwaters were moving to the actively eroding Cache Creek valley and a south and west oriented tributary valley as well as to the actively eroding east-northeast oriented Pilot Creek valley. A reversal of flood flow created the north-northeast oriented Republic Creek drainage route. Since floodwaters ceased flowing across the region the entire region has been significantly uplifted, although high passes like Republic Pass provide evidence of the former flood flow routes.

Detailed map of Cache Creek-North Fork Crandall Creek drainage divide area

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

Figure 6 uses a detailed topographic map to illustrate the Cache Creek-North Fork Crandall Creek drainage divide area seen in less detail in figure 5. The Yellowstone National Park eastern boundary is the well-marked line following the high mountain ridge from the north edge to the south edge of figure 6. The northwest oriented stream flowing to the northwest corner of figure 6 is a Cache Creek tributary as is the northwest oriented stream in the southwest quadrant of figure 6. Both streams turn flow in a west direction before joining south-southwest oriented Cache Creek, which then joins the northwest oriented Lamar River. The North Fork Crandall Creek flows from section 36 to the southeast corner of figure 6 and south and east of figure 6 flows in a southeast and east-southeast direction to join east-northeast oriented Crandall Creek, which then joins Clarks Fork Yellowstone River. Note how along the west margin of section 21 a deep pass links the northwest oriented Cache Creek tributary valley with the southeast oriented North Fork Crandall Creek valley. The map contour interval for figure 6 is 40 feet and the elevation at the pass is between 9680 and 9720 feet.  Elevations to the north rise to more than 10,240 feet and to more than 10,600 feet north of figure 6 and elevations to the south rise to more than 9960 feet in figure 6 and to more than 10,600 feet south of figure 6. Based on which elevations are used the pass is anywhere from 240 to 880 feet deep. While insignificant compared to the much deeper valleys on either side of the high drainage divide the pass is a remnant of a water-eroded valley and was probably eroded by a southeast oriented flood flow channel moving floodwaters from the present day northwest oriented Cache Creek tributary alignment to the southeast oriented North Fork Crandall Creek alignment. At that time there was no deep south-southwest oriented Cache Creek valley west of figure 6 and floodwaters were eroding flood flow channels into a surface equivalent in elevation to the higher ridges seen in figure 6. Headward erosion of a deep south-southwest oriented valley on the Cache Creek alignment west of figure 6 beheaded and reversed the flood flow to create the northwest oriented Cache Creek tributary drainage route. South oriented flood flow from north of figure 6 probably contributed to the erosion of the deep northwest oriented Cache Creek tributary valley before being beheaded by headward erosion of deeper valleys north and west of figure 6.

South Cache Creek-Timber Creek drainage divide area

Figure 7: South Cache Creek-Timber Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 7 illustrates the South Cache Creek-Timber Creek drainage divide area south of figure 5 and includes overlap areas with figure 5. The Yellowstone National Park boundary is shown with a dashed line and follows the Lamar River-Clarks Fork Yellowstone River drainage divide from the north center edge of figure 7 to the south center edge of figure 7. Cache Creek flows in a south-southwest direction from the north edge of figure 7 (west half) to the west edge of figure 7 (south of center) and joins the northwest oriented Lamar River west of figure 7. South Cache Creek originates near the center of figure 7 and flows in an east, east-southeast, and east direction to join Cache Creek near the west edge of figure 7. Note the unnamed Cache Creek tributaries north of South Cache Creek, which originate as northwest oriented streams and then turn in southwest directions to join Cache Creek. The northwest oriented valley segments are on alignments of southeast oriented flood flow channels that were beheaded and reversed by headward erosion of deeper southwest oriented valleys probably from a south-southwest oriented valley eroding headward on the Cache Creek alignment. At that time flood flow channels and valleys were being eroded into a surface equivalent in elevation to the high mountain ridges seen in figure 7. East of the Park boundary the North Fork Crandall Creek flows in an east-southeast direction in the northeast quadrant of figure 6, Closed Creek flows in a southeast, east, and southeast direction to the east edge of figure 7 (south of center) and Timber Creek flows in an east and east-northeast oriented direction to join Closed Creek near the east edge of figure 7 (the combined stream becomes Crandall Creek). Today the Lamar River-Clarks Fork Yellowstone River drainage divide is a high mountain ridge that appears to be a giant wall between the two independent drainage basins. However, a close look at the ridge top reveals numerous notches, gaps, or passes, which record locations of former southeast oriented flood flow channels that once crossed the region. For example near the center of figure 7 a notch or pass links the west oriented headwaters valley of South Cache Creek with a south-southeast tributary valley draining to the east oriented Timber Creek valley. The map contour interval for figure 7 is 50 meters and the pass elevation is between 2900 and 2950 meters. Elevations to the north rise to more than 3250 meters and elevations to the southwest rise to more than 3050 meters suggesting the pass is at least 100 meters deep. The pass was eroded by southeast oriented flood flow probably moving to deeper south oriented flood flow channels in the Big Horn Basin to the east. Headward erosion of a deeper west oriented valley on the South Cache Creek alignment captured the southeast oriented flood flow and diverted the floodwaters to a south-southwest oriented valley on the Cache Creek alignment. At that time valleys were being eroded into a surface equivalent in elevation to the highest figure 7 elevations today, although the region has probably been significantly uplifted since that time.

Detailed map of South Cache Creek-Timber Creek drainage divide area

Figure 8: Detailed map of South Cache Creek-Timber Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 8 uses a detailed topographic map to illustrate the South Cache Creek-Timber Creek drainage divide area seen in less detail in figure 7. The Yellowstone National Park east boundary is shown with the well-marked line extending along the high drainage divide from the north edge of figure 8 (west of center) to the south edge of figure 8 (west half). Closed Creek is the southeast and east oriented stream in the northeast quadrant of figure 8. Timber Creek flows in east direction from near the Park east boundary to the east edge of figure 8 (near southeast corner) and joins Closed Creek east of figure 8 to form east-northeast oriented Crandall Creek. South Cache Creek originates slightly north of the center of figure 8 and flows in west direction to the west edge of figure 8 (north of center) and then to south-southwest oriented Cache Creek. Areas east of the Park boundary have been surveyed with section numbers being assigned, which will be used here to identify locations along the Park boundary. Note along the Park boundary in section 13 a pass linking a north-northwest oriented South Cache Creek headwaters valley with a south and south-southeast oriented Timber Creek tributary valley. The map contour interval for figure 8 is 40 feet and the pass elevation is between 9600 and 9640 feet. Elevations along the east edge of section 18 to the northeast rise to more than 10,120 feet and near the north edge of section 23 to the southwest elevations also rise to more than 10,120 feet. These elevations suggest the pass is approximately 500 feet deep. The pass was eroded by south-southeast oriented flood flow at a time when the deep South Cache Creek valley did not exist and when floodwaters were flowing on a surface at least as high as the pass floor elevation today. At that time there was no deep Yellowstone River valley in Montana to the north and the Absaroka Mountains did not stand high as they do today. The Absaroka Mountains were raised as floodwaters flowed across them and as progressively deeper and deeper valleys eroded headward into them to capture the massive south and southeast oriented melt water floods.

Timber Creek-Miller Creek drainage divide area

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

Figure 9 illustrates the Timber Creek-Miller Creek drainage divide area south and slightly east of figure 7 and includes overlap areas with figure 7. The Yellowstone National Park east boundary is shown with a dashed line extending from the north edge of figure 9 (west of center) to the south edge of figure 9 (east of center). West of the Park boundary the Lamar River originates in the Hoodoo Basin area and flows in a north, west, and southwest direction before turning to flow in a northwest direction across the southwest corner of figure 9. Miller Creek originates near the center of figure 9 and flows in a northwest and west direction to join the northwest oriented Lamar River west of figure 9. East of the Park boundary Hoodoo Creek flows in a north and north-northeast direction to the east edge of figure 9 and joins east-northeast oriented Crandall Creek north and east of figure 9 (with Crandall Creek flowing to the Clarks Fork Yellowstone River). Papoose Creek originates just east of the Miller Creek headwaters and flows in a northeast direction to the north edge of figure 9 (near northeast corner) and joins Crandall Creek north and east of figure 9. Timber Creek flows in an east direction along the north edge of figure 9 and joins Closed Creek north of figure 9 to form east-northeast oriented Crandall Creek. Numerous notches, gaps, or passes cross the Lamar River-Clarks Fork Yellowstone River drainage divide providing evidence of flood flow channels that once crossed the region. For example note the pass linking the west oriented Miller Creek valley with the northeast oriented Papoose Creek valley. The map contour interval for figure 9 is 50 meters and the pass elevation is between 2750 and 2800 meters. Elevations to the south rise to 3214 meters and to the north to at least 3150 meters suggesting the pass or gap is at least 350 meters deep. The pass or gap was probably eroded by southeast and east oriented flood flow moving from the present day northwest oriented Lamar River and west oriented Miller Creek alignment to the northeast oriented Papoose Creek valley, which had eroded headward from the much deeper Clarks Fork Yellowstone River valley. This flood flow U-turn typifies the complex flood flow movements as deeper and deeper valleys eroded headward into the region to capture the southeast oriented flood flow. An alternate interpretation is the Papoose Creek alignment was first established as a southwest oriented flood flow channel moving floodwaters to the Yellowstone National Park region and then was beheaded and reversed by headward erosion of the much deeper Crandall Creek valley from the southeast oriented Clarks Fork valley. Evidence of flood flow channels can also be seen along drainage divides between the Lamar River and Lamar River tributaries (and also between Clarks Fork tributaries). For example east of Hague Mountain a northwest-to-southeast oriented pass or through valley links a north oriented Miller Creek tributary valley with Lamar River valley (where the Lamar River turns to flow in a southwest direction). The pass elevation is between 2900 and 2950 meters. Hague Mountain rises to more than 3200 meters and elevations rise to 3110 meters to the east suggesting the pass is at least 150 meters deep. The pass was eroded by southeast oriented flood flow prior to headward erosion of the deep west oriented Miller Creek valley.

Detailed map of Timber Creek-Miller Creek drainage divide area

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

Figure 10 illustrates the Timber Creek-Miller Creek drainage divide area seen in less in figure 9. The Yellowstone National Park eastern boundary is also the well-marked Wapiti Ranger District western boundary and extends from the north edge of figure 10 (west half) to the south edge of figure 10 (east half). Bootjack Gap is located near the center of figure 10 and links the east-northeast oriented Papoose Creek valley with the west-northwest oriented Miller Creek valley. East of figure 10 Papoose Creek flows to Crandall Creek, which flows to Clarks Fork Yellowstone River and Miller Creek flows in the opposite direction to the Lamar River. The map contour interval for figure 10 is 40 feet and the Bootjack Gap elevation is between 9120 and 9160 feet. North of Bootjack Gap elevations along drainage divide rise to more than 10, 360 feet. Hoodoo Peak to the south has an elevation greater than 10,520 feet. These elevations suggest Bootjack Gap may be as much as 800 feet deep. Bootjack Gap is a water eroded valley and was probably eroded by southeast and east oriented floodwaters moving on the present day northwest oriented Lamar River alignment and west oriented Miller Creek alignment to the northeast oriented Papoose Creek alignment and then to the much deeper Clarks Fork Yellowstone River valley, which at that time was probably flowing to south oriented flood flow channels in the present day north oriented Big Horn Basin. Absaroka Range uplift as floodwaters flowed across the region combined with headward erosion of a deeper south-southeast oriented valley west of figure 10 beheaded and reversed the east and northeast oriented flood flow channel and created the west oriented Miller Creek drainage route. South oriented flood flow from north of figure 10 may have continued to flow into the Miller Creek valley after the reversal of flood flow and may helped erode the deep Miller Creek valley seen today.

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.