Greybull River-Wind River drainage divide area landform origins in the Wyoming Absaroka Range, USA

Authors


Abstract:

This essay uses topographic map evidence to interpret landform origins in the Greybull River and Wind River drainage divide area located in the Wyoming Absaroka Range. The Wind River flows in a southeast direction between the Absaroka Range and the Wind River Mountains into the Wind River Basin and then turns to flow in a north direction through Wind Canyon to the Bighorn Basin. Once in the Bighorn Basin the river name changes to the Bighorn River, although the river continues to flow in a north direction. The Greybull River originates in the southern Absaroka Range, but north of the southeast oriented Wind River, and flows in a north-northwest direction before turning to flow in an east and northeast direction into the Bighorn Basin where it eventually joins the north oriented Bighorn River. Passes crossing high mountain ridges link north oriented Greybull River tributary and headwaters valleys with south oriented Wind River tributary valleys. These passes when viewed in the context of the valleys they link can be interpreted as evidence of a south oriented anastomosing channel complex that had been eroded into a surface now preserved, if preserved at all, by flat-topped mountains found throughout the Greybull River-Wind River drainage divide region. Floodwaters are interpreted to have been derived from the western margin of a thick North American ice sheet and were flowing from western Canada to and across the present day Absaroka Range location. At that time the Absaroka Range had not emerged as a mountain range and floodwaters could flow across what is today a high mountain range. Absaroka Range emergence occurred as floodwaters flowed across it and was caused by ice sheet related crustal warping and by the headward erosion of deep valleys into the rising mountain mass. Headward erosion of the deep southeast oriented Wind River valley captured the south oriented flood flow first and deep south oriented Wind River tributary valleys then eroded headward into the rising Absaroka Range mountain mass. Next headward erosion of the northeast oriented Wood River valley from the actively eroding northeast oriented Greybull River valley captured the south and southeast oriented flood flow and beheaded some flood flow routes to south oriented Wind River tributary valleys. Headward erosion of the east oriented Greybull River valley beheaded a major south-southeast oriented flood flow channel to the newly eroded northeast oriented Wood River valley. Floodwaters on the north-northwest end of the beheaded flood flow channel reversed flow direction to create the north-northwest oriented Greybull River headwaters drainage route and beheaded and reversed additional south oriented flood flow routes to south oriented Wind River tributary valleys.

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 Greybull River-Wind River drainage divide area landform origins in the Wyoming Absaroka Range. 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 Greybull River –Wind River drainage divide area landform evidence in the Wyoming Absaroka Range will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm.

Greybull River-Wind River drainage divide area location map

Figure 1: Greybull River-Wind 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 Greybull River-Wind River drainage divide area in the Wyoming Absaroka Range and illustrates northwest Wyoming. North and west Wyoming state lines are located along the north and west edges of figure 1. Yellowstone National Park is located in the northwest corner of figure 1. The Absaroka Range extends along the eastern boundary of Yellowstone National Park to the Owl Creek Mountains. The Wind River flows in a southeast direction from Togwotee Pass (in southwest quadrant of figure 1) to the south center edge of figure 1 and south of figure 1 turns to flow in a north direction to Boysen Reservoir (straddles south edge near southeast corner of figure 1) and then flows through Wind River Canyon (not labeled in figure 1, but a deep canyon carved across the Owl Creek Mountains) to near Thermopolis where the river name changes to become the Bighorn River. The Bighorn River then flows in a north direction from Thermopolis to the north edge of figure 1 (near northeast corner). North of figure 1 the Bighorn River flows in a north-northeast direction to join the northeast oriented Yellowstone River, which then flows to the Missouri River.  The Greybull River originates near where Absaroka Range meets the Owl Creek Mountains and flows in a north-northwest, east, and northeast direction to the town of Meeteetse and then flows in a northeast, east-southeast, and northeast direction to join the Bighorn River near the town of Greybull. The unlabeled northeast oriented stream originating south of Francs Peak and joining the Greybull River near Meeteetse is the Wood River. The South Fork Shoshone River is located west of the Greybull River. The Greybull River-Wind River drainage divide area in the Wyoming Absaroka Range is located in the southeastern Absaroka Range and is bounded on the west by the South Fork Shoshone River headwaters, on the east by the Wood River and Owl Creek Mountains, and on the south by the Wind River drainage basin.

At one time the region in figure 1 was crossed by massive south and southeast oriented melt water floods from the western margin of a thick North American ice sheet. At that time the Absaroka Range and the Owl Creek Mountains had not emerged as mountain ranges and the immense south and southeast oriented melt water floods could flow across what are today high mountain ridges. The mountains emerged as ice sheet related crustal warping raised them and as deep valleys eroded headward into them. Headward erosion of the deep valleys into the emerging mountain areas was to capture the massive south and southeast oriented flood flow. The present day Bighorn River is located on the alignment of what began as a major south oriented flood flow channel, which south of the southeast corner of figure 1 converged with a southeast oriented flow channel on the southeast oriented Wind River alignment. Flood flow on the Bighorn River alignment was reversed when headward erosion of the much deeper northeast oriented Yellowstone River valley from space in the deep “hole” the melting ice sheet had once occupied beheaded a south oriented flood flow channel supplying floodwaters to the south oriented Bighorn River flood flow channel. Floodwaters on the north end of the beheaded flood flow channel reversed flow direction to create the north oriented Bighorn River drainage route, which captured the southeast oriented Wind River flood flow channel. Deep northeast oriented valleys then eroded headward from the newly reversed Bighorn River flood flow channel to capture flood flow still moving in south and southeast directions west of the actively eroding Yellowstone River valley head. The deep northeast oriented Wood River valley captured southeast and south oriented flood flow in the Absaroka Range area first, headward erosion of the deep east oriented Greybull River beheaded and reversed south-southeast oriented flood flow channel to the newly eroded northeast oriented Wood River valley, and subsequently South Fork Shoshone River valley headward erosion captured southeast and south oriented flood flow moving to the newly eroded Greybull River valley. What are today high mountain ridges were carved by systematic headward erosion of these deep valleys and their tributary valleys into a rising mountain mass to capture the immense south and southeast melt water flood flow.

Detailed location map for Greybull River-Wind River drainage divide area

Figure 2: Detailed location map Greybull River-Wind 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 Greybull River-Wind River drainage divide area in the Wyoming Absaroka Range. Meeteetse is the town near the northeast corner of figure 2. Pitchfork is a small town west of Meeteetse in the northeast quadrant of figure 2. The Greybull River flows in a north-northwest and east direction from the Absaroka Range (near center of figure 2) to Pitchfork and then in an east and northeast direction to Meeteetse. North and east of figure 2 the Greybull River flows to the north oriented Bighorn River. The Wood River is a major northeast oriented Greybull River tributary originating slightly south and east of the Greybull River headwaters and joining the Greybull River near the northeast corner of figure 2. Labeled Wood River tributaries include the Middle and South Forks. Anderson Creek and Venus Creek are labeled north-northeast tributaries west of the north-northwest oriented Greybull River segment. West of Anderson Creek is the South Fork Shoshone River drainage basin. The South Fork Shoshone River originates near Crescent Mountain and flows in a north-northeast direction to the north edge of figure 2 (slightly west of center). Needle Creek is the north and west oriented South Fork Shoshone River tributary west of Anderson Creek. South of the Needle Creek, Greybull River, and Wood River headwaters are headwaters of south oriented Wind River tributaries. The Wind River originates near Togwotee Pass (near west edge of figure 2, slightly south of center) and flows in a southeast direction to the south edge of figure 2 (near the town of DuBois). One labeled south oriented Wind River tributary of interest in this essay is Wiggins Fork and its tributaries Frontier Creek, Caldwell Creek, and Bear Creek. Wiggins Fork flows to the south oriented East Fork Wind River, which then flows to the southeast oriented Wind River. South oriented Wind River tributaries alignments roughly correspond with alignments of some of the north oriented Greybull, Wood River, and South Fork Shoshone River tributaries, which provides a clue to the drainage route origins. Headward erosion of the deep southeast oriented Wind River valley captured south oriented flood flow before headward erosion of the deep Wood River, Greybull River, South Fork Shoshone River valleys and south oriented Wind River tributary routes eroded headward as south oriented flood channels. Northeast oriented Wood River, Greybull River, and South Fork Shoshone River valley segments were then eroded headward across the south oriented flood flow channels. Floodwaters on north and northwest ends of beheaded flood flow channels reversed flow direction to create the northwest, north-northwest, and north oriented Wood River, Greybull River, and South Fork Shoshone River drainage route segments and tributaries seen in figure 2.

Needle Creek-Emerald Creek drainage divide area

Figure 3: Needle Creek-Emerald 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 Needle Creek-Emerald Creek drainage divide area. The orange-colored line is the northern boundary of the Wind River drainage basin. The South Fork Shoshone River flows in a north-northeast direction across the northwest corner of figure 3. East Fork Creek is north oriented tributary flowing from Hidden Basin (near southwest corner of figure 3) to join the South Fork Shoshone River near the northwest corner of figure 3. Needle Creek is a north oriented stream flowing from the north edge of the Wind River drainage basin to the north center edge of figure 3. North of figure 3 Needle Creek turns to flow in a west direction to join the South Fork Shoshone River.  The north-northeast oriented stream east of Needle Creek and flowing from the north edge of the Wind River drainage basin to the north edge of figure 3 (near northeast corner) is Venus Creek, which north of figure 3 joins the north-northwest Greybull River segment. All south oriented streams south of the Wind River drainage basin northern boundary flow to Wiggins Fork, which can be seen flowing in a south and south-southwest direction to the south edge of figure 3 (east of center). From west to east the major Wiggins Fork tributaries include Frontier Creek, Emerald Creek with its tributary Sheep Creek, and Burwell Creek. Note the flat-topped uplands seen in figure 3, the largest of which is the Shoshone Plateau near the southwest corner of figure 3. The map contour interval is 50 meters and these flat-topped uplands and other high points generally have elevations in the 3400 to 3500 meter range. This 3400-3500 meter elevation represents the surface into which the present day valleys were carved. Study of the South Fork Shoshone River-Wind River and the Greybull River-Wind River drainage divides in figure 3 reveals shallow through valleys or passes linking the north oriented valleys with the south oriented Wind River tributary valleys. Also shallow north-to-south oriented passes or notches can be seen linking tributary valleys on either side of the Wind River drainage basin north boundary. These passes or through valleys are evidence of flood flow channels that were eroded into the that former 3400-3500 meter high surface by the massive south oriented flood flow prior to headward erosion of the much deeper Greybull River and South Fork Shoshone River valleys and their tributary valleys. At that time the south oriented flood flow was moving to what was then newly eroded and deep southeast oriented Wind River valley located south of figure 3. The deep south oriented Wiggins Fork valley and its tributary valleys eroded headward into the region seen in figure 3 to capture the immense south oriented melt water floods. Headward erosion of the deep Greybull River valley and subsequently of the deep South Fork Shoshone River valley and their deep tributary valleys beheaded and reversed the south oriented flood flow channels to create the drainage systems seen today.

Detailed map of Needle Creek-Emerald Creek drainage divide area

Figure 4: Detailed map of Needle Creek-Emerald 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 Needle Creek-Emerald Creek drainage divide area seen in less detail in figure 3. The labeled ranger district boundary and county line  is shown with a dashed line and is located along the South Fork Shoshone River-Wind River drainage divide and extends from the west edge of figure 4 (near southwest corner) to the north edge of figure 4 (near northeast corner). Emerald Creek originates at Emerald Lake in section 21 and flows in a south direction to join Wiggins Fork, which then flows in a south direction to join the southeast oriented Wind River. Sheep Creek originates at Sheep Lake in section 15 and flows in a south, southeast, and south direction to the south edge of figure 4 (near southeast corner). South of figure 4 Sheep Creek joins Emerald Creek. North of Emerald Lake in section 21 are headwaters of north oriented Needle Creek, which flows to the north center edge of figure 4 and north of figure 4 turns to flow in west direction to the north-northeast oriented South Fork Shoshone River. North of the north oriented Needle Creek valley segment is Boulder Creek, which flows on the same alignment to join the South Fork Shoshone River. Note in section 21 a pass linking the north oriented Needle Creek valley with the south oriented Emerald Creek valley. The map contour interval for figure 4 is 40 feet and the pass elevation is between 11,480 and 11,520 feet. The mountain peak to the west rises to 12,026 feet while the mountain peak to the east in section 21 rises to 11,954 feet and a peak reaching 12,144 feet is located near Sheep Lake. These elevations suggest the pass is more than 400 feet deep. This pass was eroded by south oriented flood flow prior to headward erosion of the South Fork Shoshone River valley and west oriented Needle Creek valley segment north of figure 4. The south and southwest oriented stream flowing to the south edge of figure 4 (near southwest corner) is Frontier Creek, which south of figure 4 joins Wiggins Fork. The west and northwest oriented stream north of Frontier Creek is Gentian Creek, which west of figure 4 joins north oriented East Fork, which flows to the north-northeast oriented South Fork Shoshone River. A much deeper north-to-south oriented pass can be seen in section 30 along the west edge of figure 4 linking the northwest oriented Gentian Creek valley with the south oriented Frontier Creek valley. The pass elevation is between 10,680 and 10,720 feet. Elevations on the drainage divide south and west of figure 4 rise to 11,687 feet suggesting the pass depth is almost 1000 feet. This pass was also eroded by south oriented flood flow from the present day north oriented East Fork valley, which was moving to the actively eroding south oriented Frontier Creek valley. Headward erosion of the much deeper South Fork Shoshone River valley beheaded and reversed the north end of the flood flow channel to create the northwest oriented Gentian Creek and north oriented East Fork drainage routes.

Greybull River-Wiggins Fork drainage divide area

Figure 5: Greybull River-Wiggins Fork drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 5 illustrates the Greybull River-Wiggins Fork drainage divide area east of figure 3 and includes a significant overlap area with figure 3. The northern boundary of the Wind River drainage basin is shown with the orange line. Mount Burwell is located near the center of figure 5 and Burwell Pass is south of Mount Burwell. Wiggins Fork flows in a north and northwest direction toward Burwell Pass and then turns to flow in a southwest and west-southwest direction to the south edge of figure 5 and south of figure 5 flows to the south oriented East Fork Wind River, which then flows to the southeast oriented Wind River. South of the Wiggins Fork headwaters are south-southeast and southwest headwaters of Caldwell Creek (not labeled in figure 5, but which flow through Black Canyon, which is labeled). A pack trail makes use of a through valley linking the northwest oriented Wiggins Fork valley segment with the south-southeast oriented Caldwell Creek headwaters valley segment. The map contour interval for figure 5 is 50 meters and the through valley elevation is between 3300 and 3350 meters. West of the through valley is a spot elevation of 3666 meters and east of the through valley elevations rise as high as 3757 meters suggesting the through valley is as much as 300 meters deep. East of the through valley is Yellow Ridge and the Greybull River originates near Greybull Pass (which is south and east of Yellow Ridge) and then flows in a north-northwest direction to the north edge of figure 5 (east of center). North of figure 5 the Greybull River turns to flow in an east and northeast direction. Greybull Pass is a through valley between the north-northwest oriented Greybull River valley and the southeast oriented Brown Basin, which drains to the northeast oriented Wood River and is further illustrated and discussed in figures 9 and 10 below. Many similar passes can be seen in figure 5 and these passes record evidence of south and south-southeast flood flow channels that once crossed the region. The north-northwest oriented Greybull River segment was created when headward erosion of the deep east oriented Greybull River valley north of figure 5 beheaded a south-southeast oriented flood flow channel. Floodwaters on the north-northwest end of the beheaded flood flow channel reversed flow direction to create the north-northwest oriented Greybull River headwaters drainage route. A similar situation occurred with the Wiggins Fork-Caldwell Creek through valley, although in that case the deep southwest oriented Wiggins Fork valley eroded headward from the newly eroded southeast oriented Wind River valley to behead a south-southeast oriented flood flow channel moving to the Caldwell Creek valley. Burwell Pass is today a notch in the high Greybull River-Wiggins Fork drainage divide with Cow Creek being the northeast oriented Greybull River tributary originating near Burwell Pass. Burwell Pass provides evidence of diverging and converging flood flow channels and has an elevation of between 3450 and 3500 meters. Mount Burwell to the northwest rises to 3753 meters and Dollar Mountain to the southeast rises to 3765 meters suggesting Burwell Pass may be as much as 250 meters deep.

Detailed map of Cow Creek-Wiggins Fork drainage divide area

Figure 6: Detailed map of Cow Creek-Wiggins Fork 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 Cow Creek-Wiggins Fork drainage divide area seen in less detail in figure 5. Wiggins Fork flows in a north-northeast direction in section 2 before turning to flow in a northwest and then southwest direction to the southwest corner of figure 6. Burwell Pass is located in the northwest corner of section 35 and Cow Creek flows in a northeast direction from near Burwell Pass to the north edge of figure 6 (east of center) and north of figure 6 joins the north-northwest oriented Greybull River. The map contour interval for figure 6 is 40 feet and the lowest Burwell Pass elevation is between 11,200 and 11,240 feet (the marked trail does not cross the drainage divide at the lowest point nor is the spot elevation at the lowest point). Mount Burwell in section 27 to the north reaches an elevation of 12,313 feet. Near the southeast corner of figure 6 there is an elevation of 12,155 feet and Dollar Mountain south of figure 6 rises to 12,353 feet. These elevations suggest Burwell Pass could be as much as 1000 feet deep. A south oriented flood flow channel eroded the Burwell Pass valley at a time when the deep Greybull River valley to the north did not exist. At that time flood flow was moving on a surface at least as high the Burwell Pass floor elevation and probably had eroded the valley into a surface as high as the highest points seen in figure 6. Floodwaters were flowing to diverging and subsequently converging south oriented flood flow channels on the present day north oriented and southwest oriented Wiggins Fork valley segments. Headward erosion of a deeper south-southeast oriented flood flow on the present day north-northwest Greybull River valley alignment (north and east of figure 6) probably beheaded and reversed the south oriented flood flow moving across Burwell Pass and created the northeast oriented Cow Creek drainage route. Subsequently headward erosion of the much deeper southwest oriented Wiggins Fork valley (from the deep south oriented East Fork Wind River valley, which had eroded headward from the southeast oriented Wind River valley) beheaded and reversed the south oriented flood flow channel on the present day north oriented Wiggins Fork headwaters alignment. Also, headward erosion of the much deeper east oriented Greybull River valley north of figure 6 beheaded and reversed the south-southeast oriented flood flow channel on the present day north-northwest Greybull River alignment. At the same as these deep valleys were eroding headward into the region to capture the immense south and southeast oriented flood flow ice sheet related crustal warping was probably raising the entire region. Headward erosion of the deep valleys into the region to capture the melt water flood flow and ice sheet related crustal warping that raised the entire region created what is today the rugged and high Absaroka Mountain Range.

Wood River-Bear Creek drainage divide area

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

Figure 7 illustrates the Wood River-Bear Creek drainage divide area south and east of figure 5 and there is a significant overlap area with figure 5. The Greybull River-Wind River drainage divide extends from the north edge of figure 7 (west of center) to the south edge of figure 7 (near southeast corner). Wiggins Fork is the southwest oriented stream flowing across the northwest corner of figure 7 and west and south of figure 7 turns to flow in south direction to the southeast oriented Wind River. Caldwell Creek flows in a south and southwest direction from near the north edge of figure 7 and the drainage divide to the west edge of figure 7 (south half) and west and south of figure 7 joins south oriented Wiggins Fork. Bear Creek originates near Bear Creek Pass (on the drainage divide north of center of figure 7) and flows in a south-southwest direction to the south edge of figure 7 (west half). North of Bear Creek Pass are headwaters of the northeast oriented Wood River, which flows to the north edge of figure 7 (east half) and which north of figure 7 joins the Greybull River. The map contour interval for figure 7 is 50 meters and the Bear Creek Pass elevation is between 3400 and 3450 meters. Dunrud Peak to the northwest rises to 3712 meters and Dollar Mountain slightly further to the northwest rises to 3765 meters. Elevations greater than 3600 meters can be found along the drainage divide east of East Fork Pass suggesting Bear Creek Pass could be as much 150 meters deep. East Fork Pass links a north oriented Wood River tributary valley with headwaters of the south oriented East Fork Wind River, which flows to the south edge of figure 7 (east of center) and then to the southeast oriented Wind River. East Fork Pass has a slightly lower elevation than Bear Creek Pass and is also approximately 150 meters deep. These high passes were eroded as south oriented flood flow channels moving floodwaters to the actively eroding south oriented Wiggins Fork and East Fork Wind River valleys. At that time the deep northeast oriented Wood River valley did not exist and floodwaters were flowing on a surface at least as high as the present day pass elevations, although the entire region has probably been uplifted since that time. Note the north-to-south oriented through valley west of Bear Creek and south of Dunrud Peak linking a west-northwest oriented Wiggins Fork tributary valley with the south oriented Bear Creek valley. The through valley (or pass) is used by a pack trail from Black Canyon to the Bear Creek valley and is evidence of a former diverging and converging flood flow channel route. Study of figure 7 valleys and passes linking those valleys suggests a large-scale south oriented anastomosing channel complex once crossed the entire region.

Detailed map of Wood River-Bear Creek drainage divide area

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

Figure 8 provides a detailed topographic map of the Wood River-Bear Creek drainage divide area seen in less detail in figure 7. The Wood River-Wind River drainage divide in the west half of figure 8 extends from the northwest corner of figure 8 to near the east center of figure 8. From the center of figure 8 the drainage divide extends in a south direction to Coal Chute Pass and the south edge of figure 8 (east of center). The Wood River originates in section 20 (in northwest quadrant of figure 8) and flows in a northeast direction to the north edge of figure 8 (east of center) and north and east of figure 8 joins the Greybull River. Bear Creek originates in section 29 and flows in southwest and south direction to the southwest corner of figure 8. The East Fork Wind River originates near the east edge of section 28 (south of East Fork Pass) and flows in a south direction to the south center edge of figure 8. South of figure 8 Bear Creek and East Fork Wind River flow eventually reaches the southeast oriented Wind River. The northeast oriented stream flowing across the southeast corner of figure 8 is the Middle Fork Wood River. Bear Creek Pass links a north oriented Wood River headwaters valley with the southwest and south oriented Bear Creek valley. East Fork Pass links a north oriented Wood River tributary valley with the south oriented East Fork Wind River valley. The map contour for figure 8 is 40 feet and the Bear Creek Pass elevation is shown as 11,211 feet while the East Fork Pass elevation is shown as 11,171 feet. Dunrud Peak in the northwest corner of figure 8 has an elevation of 12,201 feet and an elevation of 11,883 feet is located in section 27 east of East Fork Pass. These elevations suggest the passes are approximately 700 feet deep. While not deep compared with the nearby valleys the passes and the valleys they link are evidence of former south oriented flood flow channels that were eroded into a surface equivalent in elevation if not higher to the Wood River-Wind River drainage divide elevations seen today (although regional uplift has probably occurred since that time). When flood flow moved in those flood flow channels the regional topography looked very different from how it looks today. There was no deep Wood River valley and the south oriented Bear Creek and East Fork Wind River valleys were being eroded headward into the region by the massive south oriented flood flow. Headward erosion of the deep northeast oriented Wood River valley captured the south oriented flood flow channels in sequence from east to west and floodwaters on north ends of the beheaded flood flow channels reversed flow direction to create the north oriented Wood River tributary drainage routes and also to create the Wood River-Wind River drainage divide.

Greybull River-Wood River drainage divide area

Figure 9: Greybull River-Wood River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 9 illustrates the Greybull River-Wood River drainage divide area and is located north and east of figure 7 and includes a significant overlap area with figure 7. The drainage divide between the Greybull River and the Wind River is located along the orange line crossing the southwest quadrant of figure 9. The map contour interval for figure 9 is 50 meters. The Wood River originates in the southwest quadrant of figure 9 (north of Bear Creek Pass) and flows in a northeast, east, and northeast direction to near the northeast corner of figure 9. North and east of figure 9 the Wood River joins the Greybull River. The Greybull River originates near Greybull Pass (in west center area of figure 9) and flows in a north-northwest direction to the north edge of figure 9 (near northwest corner). North of figure 9 the Greybull River turns to flow in an east and northeast direction to eventually join the north oriented Bighorn River (which originated as the southeast oriented Wind River south of figure 9). Dundee Mountain is a flat-topped upland near the center of figure 9 with elevations greater than 3600 meters and represents a relic of the high level surface that once extended across the entire region. South and southeast oriented flood flow moved across that high level surface and eroded what became an ever-changing complex of anastomosing flood flow channels in that upland surface. Headward erosion of the deep southeast oriented Wind River valley south of figure 9 captured the south and southeast oriented flood flow first and deep south oriented Wind River tributary valleys then eroded headward along the deepest south oriented flood flow channel routes. Greybull Pass is an interesting northwest-to-southeast oriented pass or through valley linking the north-northwest oriented Greybull River valley with the southeast oriented Brown Basin valley, which drains to the northeast oriented Wood River. The Greybull Pass elevation is between 3400 and 3450 meters. Brown Mountain to the northeast reaches 3707 meters and Mount Crosby to the southwest reaches 3794 meters suggesting Greybull Pass is approximately 250 meters deep. Greybull Pass was eroded by south-southeast oriented flood flow channel moving floodwaters to what was then the actively eroding northeast oriented Wood River valley. At that time there was no deep east oriented Greybull River valley north of figure 9. Headward erosion of the deep east oriented Greybull River valley beheaded the south-southeast oriented flood flow channel. Floodwaters on the north-northwest end of the beheaded flood flow channel reversed flow direction to create the north-northwest oriented Greybull River drainage route seen in figure 9.

Detailed map of Greybull River-Wood River drainage divide area

Figure 10: Detailed map of Greybull River-Wood River 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 Greybull River-Wood River drainage divide area seen in less detail in figure 9. The Wood River flows in a northeast direction from the south center edge of figure 10 to the east edge of figure 10 (near northeast corner). Greybull Pass is located near the center of figure 10. Brown Basin is a steep southeast oriented Wood River tributary valley located on the southeast side of Greybull Pass. The north and north-northwest oriented drainage route originating on the west side of Greybull Pass is the Greybull River. The map contour interval for figure 10 is 40 feet and the Greybull Pass elevation is between 11,240 and 11,280 feet. Brown Mountain to the north rises to 12,161 feet and Mount Crosby to the south rises to 12,449 feet. These elevations suggest Greybull Pass could be as much as 900 feet deep. Today Greybull Pass is a rather unimpressive notch in a high mountain ridge. However, Greybull Pass is evidence of a south-southeast oriented flood flow channel that was captured by headward erosion of the much deeper northeast oriented Wood River valley and subsequently beheaded and reversed by headward erosion of the much deeper east oriented Greybull River valley north and west of figure 10. West of the Greybull River headwaters is northeast oriented Yellow Creek, which is a Greybull River tributary. Still further west is north-northeast oriented Calf Creek, which flows to northeast oriented Steer Creek, which then flows to the Greybull River (north of figure 10). Horse Creek is the east and southeast oriented stream originating in section 8 (south of Yellow Creek headwaters) and joining the northeast oriented Wood River as a barbed tributary (near south center edge of figure 10). In section 8 deep notches in the Greybull River-Wood River drainage divide link the Yellow Creek and Horse Creek valleys. The deepest notch is near the east edge of section 8 and has an elevation of between 11, 240 and 11,280 feet (almost the same as the Greybull Pass elevation) and was eroded by southeast oriented flood flow moving to the actively eroding southeast oriented Horse Creek valley, which had eroded headward from the newly eroded Wood River valley. The flood flow was probably flowing across what is now a notch in the southwest quadrant of section 5 linking the Calf Creek valley with the Yellow Creek valley. That notch was eroded into a high level surface equivalent in elevation to the present day Yellow Ridge elevation (elevations on Yellow Ridge range from 11,600 feet to more than 11,800 feet). Probably the entire region has been significantly uplifted since that time.

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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