Abstract:

This essay uses topographic map evidence to interpret landform origins in the region between the North Fork Little Wind River and North Popo Agie River in the Wyoming Wind River Range. The North Popo Agie River originates in the high Wind River Range next to the east-west continental divide and flows in an east and northeast direction to join other streams forming the northeast oriented Popo Agie River. The North and South Forks of the Little Wind River are located north of the North Popo Agie River and originate in the high Wind River Range also near the east-west continental divide and flow in north, northeast, and east directions into the Wind River Basin to form the southeast oriented Little Wind River, which then joins the northeast oriented Popo Agie River. The Popo Agie River joins the north oriented Wind-Bighorn River, which flows to the northeast oriented Yellowstone River with water eventually reaching the Gulf of Mexico. Through valleys cross the North Fork Little Wind River-South Fork Little Wind River drainage divide and the South Fork Little Wind River-North Popo Agie River drainage divide and link north oriented tributary valleys with south oriented tributary valleys. The through valleys and other evidence such as elbows of capture and barbed tributaries are interpreted in the context of immense south oriented floods that crossed the region prior to Wind River Range emergence as a high mountain range. Floodwaters were derived from the western margin of a thick North American ice sheet and were flowing from western Canada to and across Wyoming. The Wind River Range emerged as floodwaters deeply eroded surrounding regions and as ice sheet related crustal warping raised the Wind River Range. Ice sheet related crustal warping also created a deep “hole” in which the ice sheet was located. Headward erosion of the deep northeast oriented Yellowstone River valley from space being opened up by ice sheet melting at the south end of the deep “hole” beheaded a south oriented flood flow channel on the present day north oriented Wind-Bighorn River alignment. Floodwaters on the north end of the beheaded flood flow channel reversed flow direction to flow in a north direction to the much deeper Yellowstone River valley. The northeast oriented Popo Agie River valley and its northeast and east oriented North Popo Agie River valley then eroded headward from this newly formed north oriented Wind-Bighorn River drainage route to capture south oriented flood flow west of the reversed flood flow channel. Headward erosion of the Little Wind River valley and its tributary South Fork Little Wind River valley next captured the south oriented flood flow and beheaded flood flow routes to the newly eroded North Popo Agie River valley. North Fork Little Wind River valley headward erosion then captured south oriented flood flow and beheaded flood flow routes to the newly eroded South Fork Little Wind River valley.  As each deep valley eroded headward and beheaded flood flow routes floodwaters on north end of beheaded flood flow routes reversed flow direction to create north oriented drainage routes. Headward erosion of the southeast oriented Wind River valley and other Wind River tributary valleys subsequently ended flood flow across the region and further eroded the Wind River northeast flank. Continued crustal warping raised the emerging Wind River Range and after the Wind River Range had emerged as a high mountain range North Popo Agie River, South Fork Little Wind River, and North Fork Little Wind River headwaters valleys were glaciated with glaciers deepening and otherwise modifying the valleys to produce landscape features seen today.

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 North Fork Little Wind River-North Popo Agie River drainage divide area landform origins in the Wyoming Wind River Range, 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 North Fork Little Wind River-North Popo Agie River drainage divide area landform evidence in the Wyoming Wind River Range will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm.

North Fork Little Wind River- North Popo Agie River drainage divide area location map

Figure 1: North Fork Little Wind River-North Popo Agie 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 North Fork Little Wind River-North Popo Agie River drainage divide area in the Wyoming Wind River Range and illustrates a region in west-central Wyoming. Togwotee Pass is located near the northwest corner of figure 1 and Union Pass is located south and east of Togwotee Pass. The Wind River Range extends in a southeast direction from near Union Pass to near South Pass. The Wind River originates near Togwotee Pass and flows in a southeast direction between the Wind River Range and Owl Creek Mountains to Riverton, which is located in the Wind River Basin. At Riverton the Wind River turns to flow in a northeast and north direction across the Owl Creek Mountains east end (north of Boysen Reservoir) to Thermopolis in the Bighorn Basin. Once in the Bighorn Basin the Wind River name changes to become the Bighorn River and north of figure 1 the Bighorn River flows in a north direction to enter Montana and then to join the northeast oriented Yellowstone River with water eventually reaching the Gulf of Mexico. The Popo Agie River is the northeast oriented Wind River tributary flowing from Lander to Riverton and is not labeled in figure 1. Popo Agie River headwaters are located in the Wind River Range with the North Fork Little Wind River originating near Roberts Mountain and flowing in a northeast and east direction to join the northeast oriented South Fork Little Wind River near Fort Washakie and then to flow in an east and southeast direction to join the Popo Agie River near the town of Arapahoe. The North Popo Agie River originates between Lizard Head Peak and Wind River Peak and flows in a northeast and southeast direction to join the Popo Agie River near Lander. West and south of the Wind River Range is the Green River drainage basin with the Green River originating as a northwest oriented river south of Union Pass. The northwest oriented Green River headwaters turn to flow in a south direction near the west edge of figure 1 and then flow to the southwest corner of figure 1. South of figure 1 the Green River eventually reaches the Colorado River, which flows to the Pacific Ocean. The Sweetwater River originates south and east of Wind River Peak and flows in a south and south-southeast direction to South Pass. At South Pass the Sweetwater River turns to flow in an east-northeast and east direction to the east edge of figure 1 and east of figure 1 joins the North Platte River with water eventually reaching the Gulf of Mexico. The North Fork Little Wind River-North Popo Agie River drainage divide area investigated in this essay is located south and east of the North Fork Little Wind River and north and west of the North Popo Agie River.

Drainage routes in the Wind River Range and surrounding regions developed during immense south oriented melt water floods from the western margin of a thick North American ice sheet. The floodwaters were flowing from western Canada to and across Wyoming at a time when the Wind River Range and other regional mountain ranges did not stand high above surrounding regions as they do today. The Wind River Range and other regional mountain ranges emerged as floodwaters deeply eroded surrounding regions and as ice sheet related crustal warping raised the mountain ranges. Ice sheet related crustal warping combined with deep glacial erosion also created a deep “hole” in which the ice sheet was located. Initially there was no deep southeast oriented Wind River valley between the Owl Creek Mountains and the Wind River Range and floodwaters flowed in a south direction across the present day Wind River Range to deep south oriented valleys eroding headward from the Colorado River valley (south of figure 1). These south oriented valleys, which included the Green River valley and its tributary valleys, eroded the Wind River Range southwest flank. A major south oriented flood flow channel eroded headward just east of the emerging Wind River Range east end on the alignment of the present day north oriented Wind-Bighorn River. The south and south-southeast oriented Sweetwater River valley probably eroded headward from that south oriented flood flow channel. Headward erosion of the deep northeast oriented Yellowstone River valley in Montana beheaded and reversed the south oriented flood flow channel on the present day north oriented Wind-Bighorn River alignment. The Yellowstone River valley was eroding headward from space at the south end of the deep “hole” the ice sheet had occupied and that was being opened up by ice sheet melting. Headward erosion of the deep northeast oriented Yellowstone River valley beheaded south oriented flood flow routes to Wyoming in sequence from east to west. When the major south oriented flood flow channel on the present day north oriented Wind-Bighorn River alignment was beheaded floodwaters on the north end of the beheaded flood flow route reversed flow direction to flow to the much deeper Yellowstone River valley.

The newly formed north oriented Wind-Bighorn River drainage route rapidly eroded a much deeper north oriented valley (than the previous south oriented flood flow channel) and deep northeast, east, and southeast oriented valleys then eroded headward from the much deeper north oriented Wind-Bighorn River valley to capture south and southeast oriented flood flow still moving west of the newly formed north oriented drainage route. The northeast oriented Popo Agie River valley was one of the northeast oriented valleys, which eroded headward from the newly form north oriented Wind-Bighorn River drainage route to capture south and southeast oriented flood flow still moving across the emerging Wind River Range. Popo Agie River tributary valleys eroded headward across the south and southeast oriented flood flow in sequence from the southeast to the northwest with the northeast and southeast oriented North Popo Agie River capturing the flood flow before the South Fork Little Wind River valley beheaded flood flow routes to the newly eroded North Popo Agie River valley and tributary valleys. North Fork Little Wind River valley headward erosion next beheaded flood flow routes to the newly eroded South Fork Little Wind River valley and tributary valleys. Headward erosion of the southeast oriented Wind River and its northeast oriented Bull Lake Creek (the stream flowing through Bull Lake) next beheaded flood flow routes to the newly eroded North Fork Little Wind River valley. Headward erosion of these and other northeast oriented Wind River tributary valleys also beheaded south oriented flood flow routes crossing the emerging Wind River Range in sequence from the southeast to the northwest and further eroded the Wind River Range northeast flank and contributed to the erosion of the Wind River Basin. As floodwaters were deeply eroding the Wind River Range east, southwest, and northeast flanks ice sheet related crustal warping was also raising the Wind River Range so as to create the high mountain range seen today.

Detailed location map for the North Fork Little Wind River-North Popo Agie River drainage divide area

Figure 2: Detailed location map for the North Fork Little Wind River-North Popo Agie 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 North Fork Little Wind River-North Popo Agie River drainage divide area in the Wyoming Wind River Range. The green colored area is National Forest land in the Wind River Range. Brown colored areas are Wind River Indian Reservation lands. The east-west continental divide follows the Wind River Range crest, which extends in a southeast direction from the west edge of figure 2 (north of center) to the south edge of figure 2 (west half). South and west of the continental divide drainage flows to the Green River with water eventually reaching the Colorado River. The Wind River (not labeled in figure 2) flows in a southeast direction across the northeast corner of figure 2. East of figure 2 the Wind River turns to flow in a northeast and north direction and further north becomes the north oriented Bighorn River, which flows to the northeast oriented Yellowstone River with water eventually reaching the Gulf of Mexico. The Popo Agie River flows in a northeast direction from south and west of Lander to the east edge of figure 2 (north half) and joins the Wind River east of figure 2. Wind River Peak is a labeled high point on the Wind River Range crest near the south edge of figure 2 and Mount Washakie is located north and west of Wind River Peak. The Middle Popo Agie River originates east of Wind River Peak and flows in an east and northeast direction to Lander. The North Popo Agie River originates on the east side of the Wind River Range crest between Mount Washakie and Wind River Peak and flows in an east, northeast, and east direction to near Milford where it turns to flow in a southeast direction to join the northeast oriented Popo Agie River (a short distance downstream from Lander). The South Fork Little Wind River originates east and north of Mount Washakie and flows in a northeast direction to between the towns of Fort Washakie and Ethete where it is joined by the North Fork Little Wind River to form the Little Wind River. The Little Wind River then flows in a southeast direction from Ethete to join the northeast oriented Popo Agie River near the town of Arapahoe. Trout Creek is a northeast oriented stream joining the South Fork Little Wind River near the town of Wind River. The unlabeled east-northeast and east-southeast oriented North Popo Agie River tributary north of Black Mountain and south of the Trout Creek headwaters is Sand Creek. Other North and South Fork Little Wind River and North Popo Agie River tributaries and contour lines to illustrate topographic features are shown on topographic maps illustrated below.

North Fork Little Wind River-South Fork Little Wind River drainage divide area

Figure 3: North Fork Little Wind River-South Fork Little Wind River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 3 provides a topographic map of North Fork Little Wind River-South Fork Little Wind River drainage divide area. The map contour interval for figure 3 is 50 meters. The dashed boundary line extending in a south-southeast direction from the west edge of figure 3 (north of center) to the south edge of figure 3 (west half) is located along the Wind River Range crest and is also the east-west continental divide. South and west of the dashed line streams drain to the Green River with water eventually reaching the Colorado River and Pacific Ocean. Mount Bonneville is a labeled high point on the Wind River Range crest near the south edge of figure 3. North and slightly east of Mount Bonneville is Moraine Lake where the North Fork Little Wind River originates. From Moraine Lake the North Fork Little Wind River flows in a north and north-northeast direction to Raft Lake and then in an east direction to Twin Lakes before flowing in a northeast direction to the north center edge of figure 3. Twenty Lakes Creek is the north oriented tributary joining the North Fork Little Wind River at Raft Lake. The South Fork Little Wind River originates south of figure 3 and flows in a north direction across the south center edge of figure 3 before turning to flow in a northeast direction to the east edge of figure 3 (north half). Raft Creek is the south-southeast oriented stream originating south of the north oriented Twenty Lakes Creeks headwaters and flowing to the South Fork Little Wind River at the point where the South Fork turns from flowing in a north direction to flowing in a northeast direction. As a south oriented stream flowing to a north oriented drainage route Raft Creek is a barbed tributary. The drainage divide between the North Fork Little Wind River and South Fork Little Wind River is located in the high Wind River Range and is crossed by several identifiable north to south oriented through valleys (or passes). One of the most obvious through valleys (or passes) links the north oriented Twenty Lakes Creek valley with the south-southeast oriented Raft Creek valley. The through valley (or pass) floor elevation is between 3350 and 3400 meters. Elevations to the east of the through valley rise to 3711 meters and higher elevations are found to the west of through valley. These elevations suggest the through valley is at least 300 meters deep. The through valley is a water-eroded valley and was eroded by a south oriented flood flow channel flowing from the present day north oriented Twenty Lakes Creek alignment to the present day north oriented South Fork Little Wind River alignment (south of figure 3). Headward erosion of the much deeper northeast oriented South Fork Little Wind River valley captured the south oriented flood flow channel and floodwaters on the north end of the beheaded flood flow channel reversed flow direction to create the north oriented South Fork Little Wind River drainage route. Next headward erosion of the northeast oriented North Fork Little Wind River valley captured the south oriented flood flow channel and floodwaters on the north end of the beheaded flood flow channel reversed flow direction to create the north oriented Twenty Lakes Creek drainage route. After flood flow across the region had ended and after the Wind River Range had emerged as a high mountain range the region in figure 3 was glaciated with valley glaciers forming in many of the higher elevation valleys. While the glaciers deepened and otherwise modified valleys including creating the lake basins seen today the glaciers did not carve new valleys.

Detailed map of Twenty Lakes Creek-Raft Creek drainage divide area

Figure 4: Detailed map of Twenty Lakes Creek-Raft 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 Twenty Lakes Creek-Raft Creek drainage divide area seen in less detail in figure 3. The map contour interval for figure 4 is 40 feet. Tepee Pass is located near the center of figure 4. Trail Lake is north of Tepee Pass. Twenty Lakes Creek flows in a north direction from Trail Lake to the north edge of figure 4 and north of figure 4 flows to Raft Lake where it joins the east and northeast oriented North Fork Little Wind River. The South Fork Little Wind River (not labeled in figure 4) flows in a northeast direction across the southeast corner of figure 4. Raft Creek originates south of Tepee Pass and flows in a south-southeast direction to the south edge of figure 4 (east of center) and joins the northeast oriented South Fork Little Wind River as a barbed tributary south of figure 4. The Tepee Pass floor elevation is between 11,040 and 11,080 feet. The high point in section 9 to the east of Tepee Pass is shown as being 12,175 feet. West of Tepee Pass in section 8 the elevation rises to 12,252 feet. These elevations suggest Tepee Pass is approximately 1100 feet deep. Tepee Pass is a water-eroded valley, although alpine glaciers have since modified the valley. The through valley was eroded by south oriented flood flow moving in a south oriented flood flow channel on the present day north oriented Twenty Lakes Creek alignment to the present day north oriented South Fork Little Wind River alignment (south of figure 4). Study of the North Fork Little Wind River-South Fork Little Wind River drainage divide reveals other less obvious north-to-south oriented passes or through valleys. For example in section 7 a pass or through valley links a north oriented stream valley draining to Roberts Lake with southeast oriented headwaters of south-southeast oriented Grave Creek (which flows to the south edge of figure 4 (west of center) and which south of figure 4 enters Grave Lake and then turns to flow in an east-southeast and northeast direction to join the northeast oriented South Fork Little Wind River. This second through valley floor elevation is between 11,400 and 11,440 feet. Elevations to the east rise to 12,252 feet and to the west to 12,767 feet on Roberts Mountain. These elevations suggest the second through valley is approximately 800 feet. While this second through valley is probably a water-eroded valley at least some of its depth can probably be attributed to glacial erosion so the second through valley is not as convincing as the first through valley. However, the presence of the second through valley near the first and more convincing through valley suggests the second through valley was also eroded by south oriented flood flow.

South Fork Little Wind River-North Popo Agie River drainage divide area

Figure 5: South Fork Little Wind River-North Popo Agie River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 5 illustrates the South Fork Little Wind River-North Popo Agie River drainage divide area south and east of figure 3 and there is an overlap area with figure 3. The map contour interval for figure 5 is 50 meters. The dashed boundary line extending from the west edge of figure 5 (north half) to the south edge of figure 5 (west of center) follows the Wind River Range crest and is the east-west continental divide. Lizard Head Peak is located a short distance east of the continental divide in the southwest quadrant of figure 5. South Fork Lakes are located north of Lizard Head Peak and the South Fork Little Wind River flows in a north-northwest direction from South Fork Lakes to meet south-southeast oriented Raft Creek in the northwest quadrant of figure 5 and then to turn to flow in a northeast direction to the north center edge of figure 5. Remember Raft Creek originated at Tepee Pass with Twenty Lakes Creek flowing in a north direction north of Tepee Pass. South of Lizard Head Peak is the North Popo Agie River, which originates near Lonesome Lake and which then flows in an east and northeast direction to the east edge of figure 5 (south of center). Following the south oriented flood flow channel south from Raft Creek leads to the South Lakes Basin and then to a north-to-south oriented through valley or pass leading to a south oriented tributary valley draining to the east oriented North Popo Agie River valley. The through valley or pass floor elevation is between 3550 and 3600 meters, considerably higher than the lake to north, which has an elevation of 3205 meters. East of the through valley elevations rise to more than 3750 meters and elevations on Lizard Head Peak to the west rise to more than 3850 meters. These elevations suggest the through valley is at least 150 meters deep. South of figure 5 high level through valleys or passes cross the continental divide and link the North Popo Agie River valley with valleys of Big Sandy River tributaries with the Big Sandy River being a Green River tributary. Today these through valleys or passes are little more than minor notches in the high Wind River Range crest and it is difficult to imagine south oriented flood flow moving across the region. Yet, the valley alignments, elbows of capture, and barbed tributaries indicate Twenty Lakes Creek (north of figure 5), Tepee Pass, Raft Creek, the north oriented South Fork Little Wind River, and the south oriented North Popo Agie River tributary alignments originated as a south oriented flood flow channel, which was first captured by headward erosion of east oriented North Popo Agie River valley, next captured by headward erosion of the northeast oriented South Fork Little Wind River valley, and still later captured by headward erosion of the northeast oriented North Fork Little Wind River valley. Aiding these captures was crustal warping that was raising the Wind River Range so regions at the south end of the former flood flow channel were raised higher in elevation than regions further to the north.

Detailed map of South Fork Little Wind River-North Popo Agie River drainage divide area

Figure 6: Detailed map of South Fork Little Wind River-North Popo Agie River 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 South Fork Little Wind River-North Popo Agie River drainage divide area seen in less detail in figure 5. The map contour interval for figure 6 is 40 feet. The red boundary line in the west half of figure 6 follows the east-west continental divide. Shadow Lake in section 35 (in southwest quadrant of figure 6) drains in a northwest direction to the south oriented East Fork River (west of figure 6), which eventually joins the south oriented Green River, which then flows to the Colorado River. The South Fork Little Wind River originates in the South Fork Lakes area in sections 19 and 30 and flows in a north-northwest direction to the north center edge of figure 6. Lizard Head Peak is located in section 31 to the south and south of Lizard Head Peak is the North Popo Agie River headwaters valley. The North Popo Agie River originates at Lonesome Lake in section 2 and flows in an east direction to Lizard Head Meadows and then in an east-southeast direction to near the southeast corner of figure 6. A south-southeast oriented tributary flows from Bear Lake in section 32 to join the North Popo Agie River at Lizard Head Meadows. Two through valleys or passes link the north oriented South Fork Little Wind River valley with the south oriented Bear Lake valley. The deepest of the through valleys is located in the southwest quadrant of section 29 and has a floor elevation of between 11,600 and 11,640 feet. Elevations to the east rise to 12,529 feet in the southwest corner of section 28. Lizard Head Peak rises to 12,842 feet. These elevations suggest the through valley is approximately 900 feet deep. The second through valley is located near the north center edge of section 31 and has a floor elevation of between 11,760 and 11,800 feet, which suggests it is approximately 730 feet deep. This region has been glaciated and remnants of the glaciers are still present in the adjacent valleys. However, diverging and converging flood flow channels probably eroded these two through valleys long before the glaciation occurred, although glacial erosion has probably modified the valleys. At the time floodwaters flowed across the region the Wind River Range did not stand high above surrounding regions as it does today and floodwaters from the north could freely flow across the region. Crustal warping probably significantly raised the region seen in figure 6 while floodwaters were deeply eroding surrounding areas.

South Fork Little Wind River-Sand Creek drainage divide area

Figure 7: South Fork Little Wind River-Sand Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 7 illustrates the South Fork Little Wind River-Sand Creek drainage divide area north and east of figure 5 and includes an overlap area with figure 5. The map contour interval for figure 7 is 50 meters. The South Fork Little Wind River flows in a northeast and east direction from the west center edge of figure 7 to Washakie Reservoir (straddling the north center edge of figure 7) and north of figure 7 joins the North Fork Little Wind River to form the southeast oriented Little Wind River, which then flows to the northeast oriented Popo Agie River. Northeast oriented Little Wind River tributaries flowing to the north edge of figure 7 (east half) are Crooked Creek and Trout Creek, with Cottonwood Creek being a northeast and north oriented Trout Creek tributary. Black Mountain is located near the south center edge of figure 7. The North Popo Agie River flows in a northeast direction from the south edge of figure 7 (east of Black Mountain) through North Fork Canyon to the east edge of figure 7 (south half). East of figure 7 the North Popo Agie River turns to flow in an east and southeast direction to join the northeast oriented Popo Agie River. Mount Chauvenet is located near the southwest corner of figure 7. Sand Creek originates near Mount Chauvenet and flows in an east-northeast and southeast direction to join the North Popo Agie River east of Black Mountain. The east, northeast, and north oriented stream west of Black Mountain flowing to Sand Creek is Dickinson Creek and is linked by a through valley with the North Popo Agie River valley south of figure 7. That north-to-south oriented through valley continues in a north direction beyond the east oriented Sand Creek valley to the Trout Creek headwaters. The Trout Creek-Sand Creek drainage divide elevation is between 2850 and 2900 meters. East of the through valley elevations rise to more than 3000 meters and west of the through valley elevations rise to more than 3300 meters suggesting the Trout Creek-Sand Creek through valley is at least 100 meters deep. Further west a north-northwest to south-southeast through valley links the north-northwest oriented East Fork Marys Creek and Marys Creek valley with the Sand Creek valley (the East Fork flows to and through Squaw Lake and Marys Lake to join the north-northeast oriented West Fork and to form north-northwest oriented Marys Creek, which then flows to the northeast oriented South Fork Little Wind River). The East Fork Marys Creek-Sand Creek through valley south of Squaw Lake has a floor elevation of between 3150 and 3200 meters. Elevations east of the through valley rise to more than 3300 meters while elevations west of the through valley rise to more than 3500 meters suggesting the through valley is at least 150 meters deep. Orientations of these and similar through valleys probably are related to the Wind River Range geologic structures, although the through valleys are also water-eroded valleys and were eroded by south oriented flood flow moving to the Sand Creek valley. Headward erosion of the deeper northeast oriented Trout Creek valley captured the flood flow in the eastern through valley and floodwaters on the north end of the beheaded flood flow route then reversed flow direction to create the north oriented Trout Creek headwaters drainage route. Subsequently headward erosion of the South Fork Little Wind River valley captured the flood flow and floodwaters on the north end of the beheaded eastern flood flow route (to the newly eroded Trout Creek valley) reversed flow direction to create a north oriented South Fork Little Wind River tributary drainage route (tributary in shown, but not labeled) and still later to create the north-northwest oriented East Fork Marys Creek and Marys Creek drainage route.

Detailed map of Trout Creek-Sand Creek drainage divide area

Figure 8: Detailed map of Trout Creek-Sand 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 Trout Creek-Sand Creek drainage divide seen in less detail in figure 7 above. The map contour interval for figure 8 is 40 feet. Sand Lake is located in section 1 in the southwest quadrant of figure 8. Sand Creek originates south of the figure 1 and flows in a northeast direction to Sand Lake. Sand Creek then flows from Sand Lake in an east direction before turning to flow in a southeast direction to the southeast corner of figure 8. South and east of figure 1 Sand Creek joins the North Popo Agie River. Mosquito Park is located in the west half of section 24 (north of Sand Creek). Trout Creek originates in Mosquito Park and flows in a north, northeast, and east-northeast direction to near the northeast corner of figure 8. North and east of figure 8 Trout Creek joins the Little Wind River. Mosquito Park is located in a north to south oriented through valley linking the north oriented Trout Creek headwaters valley with the east oriented Sand Creek valley and also with the north and northeast oriented Dickinson Creek valley (mostly south of figure 8). The Mosquito Park elevation is shown as being 9460 feet. The high point in section 24 to the east of Mosquito Park is shown as 10,005 feet. Elevations west of Mosquito Park rise to 10,960 feet at Mount Cross. These elevations suggest the Trout Creek-Sand Creek through valley at Mosquito Park is at least 545 feet deep. Further west the East Fork Marys Creek originates in the northwest quadrant of section 1 (north of Sand Lake) and then flows in north-northwest direction to Squaw Lake and Marys Lake before reaching the northwest corner of figure 8. North of figure 8 Marys Creek joins the northeast oriented South Fork Little Wind River. A deep through valley between Mount Cross and Hobbs Peak links the north-northwest oriented East Fork Marys Creek valley with the deeper east oriented Sand Creek valley. The elevation at the East Fork Marys Creek-Sand Creek drainage divide is between 10,320 and 10,360 feet. Mount Cross reaches an elevation of 10,960 feet and Hobbs Peak reaches an elevation of 11,563 feet suggesting the through valley is approximately 600 feet deep. Other north to south oriented through valleys can be seen crossing the South Fork Little Wind River-Sand Creek drainage divide such west of Hobbs Peak in the west half of section 2. These through valleys were eroded by south oriented flood flow channels prior to headward erosion of the deeper northeast and east oriented South Fork Little Wind River valley. Headward erosion of the South Fork Little Wind River valley and its northeast oriented tributary valleys beheaded south oriented flood flow routes to the newly eroded Sand Creek valley in sequence from east to west. Floodwaters on north ends of the beheaded flood flow routes reversed flow direction to flow to the deeper South Fork Little Wind River valley and to create north oriented drainage routes, which in turn created the South Fork Little Wind River-Sand Creek drainage divide.

Washakie Creek-South Fork Little Wind River drainage divide area

Figure 9: Washakie Creek-South Fork Little Wind River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 9 illustrates the Washakie Creek-South Fork Little Wind River drainage divide area west and slightly north of figure 7 and there is an overlap area with figure 7. The map contour interval for figure 9 is 50 meters. The North Fork Little Wind River flows in a north-northeast direction from the west edge of figure 9 (south of center) to Raft Lake and then in a northeast and east direction to the east edge of figure 9 (near northeast corner). Washakie Park is located north of the center of figure 9. Washakie Creek flows in a northeast and north-northeast direction to and through Washakie Park to join the North Fork Little Wind River south of the north center edge of figure 9. Mount Shoshone is located west of the center of figure 9 and Shoshone Lake is located west of Mount Shoshone. Shoshone Creek flows in a north direction to join the North Fork Little Wind River downstream from Twin Lakes. Raft Creek is the north oriented stream west of Shoshone Creek flowing to Raft Lake. The South Fork Little Wind River flows in a northeast and east direction from the south edge of figure 9 (slightly west of center) to Washakie Reservoir (straddling the east edge of figure 9-north of center). Trout Creek flows in a northeast direction across the southeast corner of figure 9. Study of the North Fork Little Wind River-South Fork Little Wind River drainage divide in figure 9 (east of Raft Creek) reveals through valleys linking north oriented North Fork Little Wind River tributary valleys with south oriented South Fork Little Wind River tributary valleys. Perhaps the easiest through valley to see is located south of Shoshone Lake and links the north oriented Shoshone Creek valley with an east and southeast oriented South Fork Little Wind River tributary valley. The through valley floor elevation is between 3450 and 3500 meters. Elevations east of the through valley rise to more than 3550 meters and Mount Baldy to the west of the through valley rises to more than 3650 meters suggesting the through valley is at least 50 meters deep. The through valley was eroded by south oriented flood flow that was beheaded and reversed by headward erosion of the deeper northeast oriented North Fork Little Wind River valley. Further east several through valleys cross the drainage divide between Washakie Creek and a north-northeast and east-southeast oriented South Fork Little Wind River tributary. The two trails headed in an east direction from Washakie Park are located in two of those through valleys. The through valley floor elevations are both between 2800 and 2850 meters. To the northeast elevations rise to more than 2950 meters and to the southwest elevations rise much higher suggesting the through valleys are at least 100 meters deep. The through valleys were eroded by south and southeast oriented flood flow moving to the South Fork Little Wind River valley prior to headward erosion of north-northeast oriented Washakie Creek valley (and prior to headward erosion of the North Fork Little Wind River valley west of Washakie Creek).

Detailed map Washakie Creek-South Fork Little Wind River drainage divide area

Figure 10: Detailed map of Washakie Creek-South Fork Little Wind 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 Washakie Creek-South Fork Little Wind River drainage divide area seen in less detail in figure 9. The map contour interval for figure 10 is 40 feet. The South Fork Little Wind River flows in a northeast and east direction across the southeast corner of figure 10 and is located in a deep canyon. The North Fork Little Wind River flows in a northeast direction across the northwest corner of figure 10 and north of figure 10 turns to flow in more of an east direction. Washakie Creek flows in a northeast direction across section 13 to Washakie Park and then turns to flow in a north-northeast direction to join the North Fork Little Wind River north of the north center edge of figure 10. Yahtic Lake in section 12 is located in a southeast and north oriented through valley diverging and then converging with the North Fork Little Wind River valley. The through valley floor elevation west of Yahtic Lake is between 8560 and 8600 feet. Elevations between the through valley and the North Fork Little Wind River valley rise to more than 8960 feet suggesting the through valley is at least 360 feet. The through valley was probably eroded as a diverging and converging flood flow channel at the time the North Fork Little Wind River valley was eroded. In time the more direct northeast oriented North Fork Little Wind River valley eroded a deeper valley headward and was able to behead the diverging flood flow channel. South and east of Washakie Park a through valley in section 17 links the north-northeast oriented Washakie Creek valley with a southeast oriented South Fork Little Wind River tributary valley. The through valley floor elevation is between 9320 and 9360 feet and elevations in section 17 to the north rise to 9849 feet suggesting the through valley is approximately 500 feet deep. The through valley was eroded by southeast oriented flood flow moving to the South Fork Little Wind River valley prior to headward erosion of the north-northeast oriented Washakie Creek valley. Interestingly the southeast oriented South Fork Little Wind River tributary valley is today a hanging valley suggesting large volumes of floodwaters from west of figure 10 entered the South Fork Little Wind River valley and eroded the deeper South Fork Canyon after flood flow ceased to flow in the through valley. Another interesting through valley is located in the northwest quadrant of section 16 and links the southeast oriented South Fork Little Wind River valley with the east, north, and northeast oriented Timmoco Creek valley, with Timmoco Creek being a North Fork Little Wind River tributary. The through valley floor elevation is between 9200 and 9240 feet. Elevations east of the through valley rise to 9645 feet suggesting the through valley is approximately 400 feet deep. The through valley (and the through valley used by the jeep trail north of the Timmoco Creek headwaters) was eroded by south oriented flood flow moving to the South Fork Little Wind River valley prior to headward erosion of the North Fork Little Wind River valley and its Timmoco Creek tributary valley. Headward erosion of the Timmoco Creek valley first captured the south oriented flood flow, which was next captured by headward erosion of the North Fork Little Wind River valley.

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.