Abstract:

This essay uses topographic map evidence to interpret landform origins in the region between Popo Agie River and the Big Sandy River along the continental divide in the Wyoming Wind River Range. The Big Sandy River originates in the high Wind River Mountains and flows in south direction with water eventually reaching the Green and Colorado Rivers and the Pacific Ocean. The Little Sandy River originates south of a north-northwest oriented Big Sandy River tributary and flows in a south direction to eventually join the Big Sandy River. The Sweetwater River originates just east of the Little Sandy River headwaters and flows in a south and south-southeast direction with water eventually reaching the North Platte River and the Gulf of Mexico. The Middle Popo Agie River originates directly north of the Sweetwater River headwaters and flows in a north-northeast and east direction with water reaching the northeast oriented Popo Agie River and north oriented Wind and Bighorn Rivers and ultimately the Gulf of Mexico. The North Popo River originates north of the Big Sandy River headwaters and flows in an east and northeast direction to join the Popo Agie River. Through valleys eroded across high mountain ridges including the east-west continental divide link headwaters valleys of the North Popo Agie, Middle Popo Agie, Sweetwater, Big Sandy, and Little Sandy Rivers. The through valleys are interpreted to have been eroded by south and southeast oriented floodwaters at a time when the Wind River Range did not stand high above regions to the north. 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 mountain range. Floodwaters eroded the Wind River Range southwest flank prior to erosion of the northeast flank. The northeast flank was eroded during a massive flood flow reversal triggered by headward erosion of the deep northeast oriented Yellowstone River valley across Montana from space at the south end of the deep “hole” the melting ice sheet had occupied. Headward erosion of the deep Yellowstone River valley beheaded a major south oriented flood flow channel flowing just east of the emerging Wind River Range. Floodwaters on the north end of the beheaded flood flow channel reversed flow direction to create the north oriented Wind-Bighorn River drainage route. The northeast oriented Popo Agie River valley with its east and northeast oriented Middle Popo Agie River and North Popo Agie River valleys then eroded headward from this newly reversed flood flow channel to capture south oriented flood flow moving across the emerging Wind River Range and to behead flood flow routes to the south oriented Sweetwater, Little Sandy, and Big Sandy River valleys. Subsequently headward erosion of the southeast oriented Wind River valley and its tributary valleys further eroded the Wind River Range northeast flank, which combined with Wind River Range uplift ended all flood flow across the Wind River Range. Following Wind River Range emergence alpine glaciers formed in the Big Sandy, Little Sandy, Sweetwater, Middle Popo Agie, and North Popo Agier River headwaters area and modified many of the previously formed 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 Popo Agie River-Big Sandy River drainage divide area landform origins along the continental divide in the Wyoming Wind River 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 Popo Agie River-Big Sandy River drainage divide area landform evidence along the continental divide in the Wyoming Wind River Range will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm.

Popo Agie River-Big Sandy River drainage divide area location map

Figure 1: Popo Agie River-Big Sandy 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 Popo Agie River-Big Sandy River drainage divide area along the continental divide in the Wind River Range and illustrates a region in west-central Wyoming. The Wind River Range crest extends in a southeast direction from Union Pass (near northwest corner of figure 1) to near South Pass and for some of that distance serves as the east-west continental divide. South and west of the Wind River Range drainage flows to the south oriented Green River, which originates south of Union Pass as a northwest oriented river, but which then turns to flow in a south direction to the south edge of figure 1 (at Fontenelle Reservoir near the southwest corner of figure 1). South of figure 1 the Green River flows in a deep canyon across the Uinta Mountains and eventually joins the Colorado River with water ultimately reaching the Pacific Ocean. The Big Sandy River is a south and southwest oriented Green River tributary originating south of Lizard Head Peak and joining the Green River south of figure 1. The Little Sandy River originates south of Wind River Peak and joins the Big Sandy River near the town of Farson. North and east of the Wind River Range the Wind River flows in a southeast direction from the north edge of figure 1 (north of Union Pass) to Riverton in the Wind River Basin and then turns to flow in a northeast and north direction across the Owl Creek Mountains east end and to enter the Bighorn Basin near Thermopolis. Upon entering the Bighorn Basin the Wind River name changes to become the Bighorn River and the Bighorn River then flows in a north direction to eventually reach Montana and to join the northeast oriented Yellowstone River with water ultimately reaching the Gulf of Mexico. The Popo Agie River is shown in figure 1, but is not labeled, and is the northeast oriented river flowing from Lander to join the Wind River near Riverton. Figure 1 shows three headwaters streams combining near Lander to form the northeast oriented Popo Agie River. These three headwaters streams from north to south are the North Popo Agie River, the Middle Popo Agie River, and the Little Popo Agie River. The Sweetwater River originates near the Little Sandy River headwaters and flows in a south and south-southeast direction to South Pass where it turns to flow in an east-northeast and east direction to the east edge of figure 1. East of figure 1 the Sweetwater River flows to the north, northeast, east, and southeast oriented North Platte River with water eventually reaching the Gulf of Mexico. The Popo Agie River-Big Sandy River drainage divide area investigated in this essay is located in the high Wind River Range with the North and Middle Popo Agie River headwaters on the north and the Big and Little Sandy River and Sweetwater River headwaters to the south and is located along the east-west continental divide.

Drainage routes in figure 1 developed during immense south oriented floods derived from the western margin of a thick North American ice sheet and which were flowing from western Canada to and across the region in figure 1. At that time the Wind River Range and other regional mountain ranges were just beginning to emerge and at first floodwaters could freely flow across what are today high mountain barriers. Mountain ranges, including the Wind River Range, emerged as floodwaters deeply eroded surrounding basins and valleys 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 massive ice sheet was located. The Wind River Range began to emerge as deep south-oriented valleys eroded headward from the deep Colorado River valley to the southwest margin of the emerging mountain range. These south oriented valleys included the deep south-oriented Green River valley and its Big Sandy and Little Sandy River tributary valleys. At that time there was no deep Wind River valley between the Wind River Range and the Owl Creek Mountains and elevations north of the Wind River Range were at least as high as the Wind River Range. Floodwaters flowing across the Wind River Range deeply eroded the Green River Basin to the south. A major south oriented flood flow route was located on the alignment of the present day north oriented Wind-Bighorn River and continued in a south direction between the emerging Wind River Range and Granite Mountains to the south edge of figure 1 and then into Colorado. The south-southeast oriented Sweetwater River valley segment was probably eroded headward from that south oriented flood flow route.

A major flood flow reversal on that south oriented flood flow route occurred when headward erosion of the deep northeast oriented Yellowstone River valley in Montana beheaded the south oriented flood flow channel. The deep Yellowstone River valley eroded headward across Montana from space at the south end of the deep “hole” the melting ice sheet had occupied and beheaded south oriented flood flow routes to Wyoming in sequence from east to west. Floodwaters on the north end of the beheaded flood flow route on the Wind-Bighorn River alignment reversed flow direction to flow in a north direction to the much deeper northeast oriented Yellowstone River valley and to create the north oriented Wind-Bighorn River drainage route. Northeast, east, and southeast oriented valleys then eroded headward from this newly formed and deeper north oriented drainage route to capture south and southeast oriented flood flow still moving west of the actively eroding Yellowstone River valley head. The northeast oriented Popo Agie River valley and its headwaters valleys eroded headward into the emerging Wind River Range to capture south and southeast oriented flood flow still crossing the emerging mountain range. The headwaters valleys were eroded in sequence with the Little Popo Agie River valley capturing the floodwaters first, the Middle Popo Agie River valley capturing the floodwaters next, and the North Popo Agie River valley capturing the floodwaters last. Headward erosion of the northeast, east, and southeast oriented Little Wind River from the Popo Agie River near the town of Arapahoe (shown, but not labeled in figure 1) subsequently beheaded all flood flow routes to the newly eroded North Popo Agie River valley. Headward erosion of these deep valleys from the newly formed and deep north oriented Wind-Bighorn River drainage route systematically eroded the Wind River Basin and Wind River Range northeast flank as the deep southeast oriented Wind River valley eroded headward between the emerging Wind River Range and the emerging Owl Creek Mountains and ended all flood flow across the emerging Wind River Range.

Detailed location map for Popo Agie River-Big Sandy River drainage divide area

Figure 2: Detailed location map Popo Agie River-Big Sandy River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 2 provides a detailed location map for the Popo Agie River-Big Sandy River drainage divide area along the continental divide in the Wind River Range. The green colored area is National Forest land in the Wind River Range. Brown colored areas along the north edge of figure 2 are located in the Wind River Indian Reservation. The east-west continental divide extends in a south-southeast direction from the north edge of figure 2 (west half) along the Wind River Range crest to Wind River Peak and then turns in a south-southwest and southeast direction to South Pass and the south edge of figure 2. South of figure 2 is the internally drained Great Divide Basin where the continental divide location is not clearly defined. The Big Sandy River originates near Wind River Peak and flows in a northwest, southwest, south, west-southwest, south, south-southwest, and south direction to the south edge of figure 2 (near southwest corner) and south of figure 2 joins the Green River with water eventually reaching the Colorado River. The Little Sandy River originates near Wind River Peak and south of a northwest oriented Big Sandy River headwaters stream. Once formed the Little Sandy River flows in a south, south-southwest, and south direction to the south edge of figure 2 (west half) and south of figure 2 joins the Big Sandy River. The Sweetwater River originates between the Little Sandy River headwaters and Atlantic Peak and flows in a south and south-southeast direction to South Pass where it turns to flow in an east-northeast direction to the east edge of figure 2 (south half). East of figure 2 the Sweetwater River joins the North Platte River with water eventually reaching the Gulf of Mexico. The Popo Agie River is formed by several tributaries and flows in a northeast direction from Lander to the north edge of figure 2 (east half). North of figure 2 the Popo Agie River joins the northeast and north oriented Wind River, which becomes the north oriented Bighorn River with water flowing to the northeast oriented Yellowstone River and eventually reaching the Gulf of Mexico. The North Popo Agie River originates north of Wind River Peak and flows in an east and northeast direction to Milford before turning in a southeast direction to join the northeast oriented Popo Agie River a short distance northeast from Lander. The Middle Popo Agie River originates east of Wind River Peak and flows in an east and northeast direction to Lander and then to join the North Popo Agie River downstream from Lander. The Little Popo Agie River originates east of Atlantic Peak and flows in an east, northeast, north-northwest, and north-northeast direction to join the Popo Agie River near the town of Hudson. Figure 2 does not show topography, but as is shown in the topographic maps below headwaters of all of these rivers are located in high mountain areas and through valleys cross drainage divides linking these diverging drainage routes. The through valleys can only be explained in the context of south oriented flood flow channels that once crossed the Wind River Range. At the time floodwaters crossed the Wind River Range the region to the north had to be at least as high as the Wind River Range crest at that time. Since that time the Wind River Basin to the north and east has been deeply eroded and the Wind River Range has been raised relative to surrounding areas.

Tayo Creek-Little Sandy River Creek drainage divide area

Figure 3: Tayo Creek-Little Sandy River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 3 provides a topographic map of Tayo Creek-Little Sandy River drainage divide area. The map contour interval for figure 3 is 50 meters. The east-west continental divide is shown with a dashed line extending from the north center edge of figure 3 to the south center edge of figure 3 and labeled as the “FOREST AND WILDERNESS BOUNDARY”. Wind River Peak is located in the north center area of figure 3. Temple Peak is located west of Wind River Peak. A Big Sandy River tributary originates at Temple Lake (north of Temple Peak) and flows in a northwest direction to the north edge of figure 3 and north of figure 3 joins the Big Sandy River, which flows in a south-southwest direction across the northwest corner of figure 3 and then in a south direction to the south edge of figure 3 (near southwest corner). The Little Sandy Creek (River) originates east of Temple Peak and flows in an east and south direction to Little Sandy Lake (in south center area of figure 3). From Little Sandy Lake Little Sandy Creek flows in a southwest and south direction to the south edge of figure 3 (slightly west of center). South of figure 3 Little Sandy Creek (River) joins the Big Sandy River with water eventually reaching the Green and Colorado Rivers. The Sweetwater River originates west of Roaring Fork Mountain (and east of the continental divide) and flows in a south direction to the south edge of figure 3 (east of center). South of figure 3 the Sweetwater River turns to flow in a south-southeast, east-northeast, and east direction to eventually join the North Platte River with water eventually reaching the Gulf of Mexico. The Middle Popo Agie River originates north of the Sweetwater River headwaters and flows in a north, north-northeast, and east-northeast direction to the north edge of figure 3. East and north of figure 3 the Middle Popo Agie River joins the Popo Agie River and water eventually reaching the north oriented Wind-Bighorn River and the northeast oriented Yellowstone River and ultimately the Gulf of Mexico. Tayo Creek is an east and east-northeast oriented Middle Popo Agie River tributary originating at Coon Lake (near center of figure 3) and joining the Middle Popo Agie River north of the Sweetwater River headwaters. The Tayo Creek headwaters at Coon Lake are linked by a through valley with the south oriented Little Sandy Creek (River) valley. The through valley (which is a hanging valley) floor elevation at Coon Lake is between 3200 and 3250 meters. Wind River Peak to the north rises to more than 4000 meters. Elevations on the unnamed mountain to the south rise to more than 3650 meters. These elevations suggest the through valley is at least 400 meters deep. The through valley provides evidence headward erosion of the deeper south oriented Little Sandy River valley beheaded east oriented flood flow to northeast oriented Middle Popo Agie River valley. Figure 4 provides a detailed map of the through valley region. Another impressive through valley links the north oriented Middle Popo Agie River headwaters valley with the south oriented Sweetwater River headwaters valley. This north-to south oriented through valley has a floor elevation of between 3150 and 3200 meters. Roaring Fork Mountain to the east rises more than 3700 meters and the unnamed mountain to the west rises to more than 3650 meters suggesting this second through valley is more than 450 meters deep. This second through valley presents a much stronger case for south oriented floodwaters flowing across the present day Wind River Range crest.

Detailed map of Tayo Creek-Little Sandy River drainage divide area

Figure 4: Detailed map of Tayo Creek-Little Sandy River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 4 provides a detailed topographic map of the Tayo Creek-Little Sandy River drainage divide area seen in less detail in figure 3. The map contour interval for figure 4 is 40 feet. The red Ranger District boundary line extending in a south-southeast direction from the north edge of figure 4 (west half) to near the south center edge of figure 4 is located along the continental divide. East of the south center edge of figure 4 the red Ranger District boundary line follows the Popo Agie River-Sweetwater River drainage divide. Little Sandy Creek (River) originates near the northwest corner of figure 4 and flows in a south-southeast and south direction to the south edge of figure 4 (west half). South of figure 4 Little Sandy Creek (River) flows to the Big Sandy River with water eventually reaching the Green and Colorado Rivers and ultimately the Pacific Ocean. Coon Lake is located in section 10 east of the Little Sandy Creek valley. Tayo Creek originates at Coon Lake and flows in an east and east-northeast direction to join the north and northeast oriented Middle Popo Agie River, which flows to the northeast corner of figure 4. North and east of figure 4 water in the Middle Popo Agie River flows to the Popo Agie, Wind, and Bighorn Rivers and then to the Yellowstone, Missouri, and Mississippi Rivers and ultimately to the Gulf of Mexico. Sweetwater Gap is located in section 18 and links the north oriented Middle Popo Agie River headwaters valley with the south oriented Sweetwater River headwaters valley. South of figure 4 the Sweetwater River flows in a south-southeast, east-northeast, and east direction to the North Platte River with water in the Sweetwater River eventually reaching the Platte, Missouri, and Mississippi Rivers and the Gulf of Mexico. Sweetwater Gap has a floor elevation of 10,327 feet. The mountain ridge to the west rises to 12,366 feet near the south center edge of figure 4. Roaring Fork Mountain to the east (and east of figure 4) rises to more than 12,400 feet. These elevations suggest Sweetwater Gap is at least 2000 feet deep. Sweetwater Gap is a water-eroded valley and was eroded by south oriented flood flow moving from the present north oriented Middle Popo Agie River drainage basin to the south oriented Sweetwater River headwaters valley. Headward erosion of the northeast oriented Middle Popo Agie River valley captured the south oriented flood flow and floodwaters on the north end of the beheaded flood flow channel reversed flow direction to create the north oriented Middle Popo Agie River headwaters. Another deep through valley in section 10 links the Tayo Creek valley with the Little Sandy Creek (River) valley. The through valley floor elevation is between 10,560 and 10,580 feet. Wind River Peak to the north of figure 4 rises to 13,192 feet and the high point in section 23 (near south center edge of figure 4) rises to 12,366 feet. These elevations suggest the Tayo Creek-Little Sandy Creek (River) through valley is approximately 1700 feet deep. Alpine glaciers filled several of the valleys seen in figure 4. The glaciers formed after the valleys had been formed and after all flood flow had ended and also after the Wind River Range had emerged as a high mountain range. While the glaciers modified some of the valleys the glaciers did not erode Sweetwater Gap, although at least some of the Tayo Creek-Little Sandy Creek (River) through valley depth can probably be attributed to glacial erosion.

North Popo Agie River-Big Sandy River drainage divide area

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

Figure 5 illustrates the North Popo Agie River-Big Sandy River drainage divide area north and west of figure 3 and there is an overlap area with figure 3. The map contour interval for figure 5 is 50 meters. The east-west continental divide is shown with a labeled dashed line and extends in a south-southeast direction from the north edge of figure 5 (west half) to the south edge of figure 5 (east half). West and south of the continental divide drainage is to the Pacific Ocean. East and north of the continental divide drainage is to the Gulf of Mexico. The East Fork River is formed at the confluence of several tributaries in the northwest quadrant of figure 5 and then flows in south, west, south, and west direction to the west edge of figure 5 (near southwest corner) and south and west of figure 5 the East Fork River eventually reaches the south oriented Green River. Temple Peak is located slightly east of the south center edge of figure 5. A Big Sandy River tributary originates at Temple Lake (north of Temple Peak) and flows in a northwest direction to Big Sandy Lake. At Big Sandy Lake the Big Sandy River originates and flows in a southwest direction to the south edge of figure 5 (west half). South of figure 5 the Big Sandy River turns to flow in a south direction and eventually joins the south oriented Green River. North of Big Sandy Lake a south oriented Big Sandy River tributary originates at Arrowhead Lake. North of Arrowhead Lake is Lonesome Lake where the North Popo Agie River originates. From Lonesome Lake the North Popo Agie River flows in an east and northeast direction to the east edge of figure 5 (north half). North and east of figure 5 water in the North Popo Agie River flow to the Popo Agie, Wind, Bighorn, Yellowstone, Missouri, and Mississippi Rivers. A deep north-to south oriented through valley links the Lonesome Lake basin with the Arrowhead Lake basin. The through valley floor elevation is between 3150 and 3200 meters. Elevations both east and west of the through valley rise to more than 3750 meters suggesting the through valley is at least 550 meters deep. The through valley is a water-eroded valley and was eroded by south oriented flood flow flowing across the present day east-west continental divide. The flood flow probably moved across the high mountain ridge north of Lonesome Lake, which means floodwaters were flowing on a surface almost as high as the highest ridges in the Wind River Range today. At that time the Wind River Range had not emerged and regions to the north were equivalent in elevation if not higher than the high mountain ridges seen in figure 5. Ice sheet related crustal warping has since raised the Wind River Range relative to adjacent regions and deep erosion of the Wind River Basin to the north contributed to the Wind River Range emergence. Two south oriented flood flow channels diverged at the Big Sandy Lake location with one of the diverging flood flow channels following the present day southwest oriented Big Sandy River alignment and the other flood flow channel following the present day north-northwest oriented Big Sandy River tributary (or Rapid Creek on more detailed maps) alignment to the Temple Lake area and then to the Little Sandy River headwaters (see figures 7 and 8).

Detailed map of North Popo Agie River-North Creek drainage divide area

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

Figure 6 provides a detailed topographic map of the North Popo Agie River-North Creek drainage divide area seen in less detail in figure 5. The map contour interval for figure 6 is 40 feet. The red county line and National Forest boundary follows the east-west continental divide. Drainage south and west of the continental divide is to the Pacific Ocean while drainage north and east of the continental divide is to the Gulf of Mexico. Lonesome Lake is located slightly west of the north center edge of figure 6. The North Popo Agie River flows in an east and east-southeast direction from Lonesome Lake to the east edge of figure 6. East of figure 6 the North Popo Agie River flows in an east and northeast direction with water eventually reaching the northeast oriented Yellowstone River before entering the Missouri River and flowing to the Mississippi River. Arrowhead Lake is located near the northeast corner of section 11 (near center of figure 6). North Creek originates at Arrowhead Lake and flows in a south direction to the south center edge of figure 6. South of figure 6, North Creek flows to Big Sandy Lake where the southwest and south oriented Big Sandy River originates. Jackass Pass is a through valley north of Arrowhead Lake linking the south oriented North Creek valley with the east oriented North Popo Agie River valley. The through valley floor elevation is between 10,520 and 10,560 feet. The high point on Warrior Peaks in the northwest quadrant of section 11 is 12,406 feet. Mitchell Peak near the south center edge of section 1 rises to 12,482 feet. These elevations suggest Jackass Pass is approximately 1800 feet deep. Jackass Pass is a water-eroded valley and was eroded by south oriented flood flow moving to the Big Sandy Lake location where the flood flow channel split into two diverging flood flow channels. One of the diverging flood flow channels followed the present day southwest oriented Big Sandy River alignment while the other diverging flood flow channel followed a present day north-northwest oriented Big Sandy River tributary alignment to the Temple Lake area and then continued to the south oriented Little Sandy River valley. Floodwaters probably flowed in a south direction to reach the Lonesome Lake basin, which means the floodwaters crossed high ridges north of Lonesome Lake. If so the floodwaters were flowing at an elevation as high as the highest Wind River Range elevations today. Headward erosion of the deeper east and northeast oriented North Popo Agie River valley captured the south oriented flood flow and diverted the floodwaters to the south end of the deep “hole” the melting ice sheet had opened up. Since that time the Wind River Range has been significantly uplifted and the Wind River Basin to the north has been deeply eroded, both of which contributed to the end of flood flow movements across the Wind River Range and to Wind River Range emergence as a major mountain range.

Big Sandy River-Little Sandy River drainage divide area

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

Figure 7 illustrates the Big Sandy River-Little Sandy River drainage divide area south and slightly west of figure 5 and includes an overlap area with figure 5. The map contour interval for figure 7 is 50 meters. The east-west continental divide is shown with a dashed line extending in a south-southeast direction from the north edge of figure 7 (east half) to the east edge of figure 7 (south half). The east oriented North Popo Agie River can be seen in the northeast corner of figure 7. Temple Peak is located in the east center area of figure 7 (west of the continental divide). Little Sandy Creek (River) originates east of Temple Peak and flows in a south direction to Little Sandy Lake (near southeast corner of figure 7). South of figure 7 Little Sandy Creek (River) flows to the Big Sandy River with water eventually reaching the Green and Colorado Rivers and the Pacific Ocean. Temple Lake is north of Temple Peak and a Big Sandy River tributary originates at Temple Lake and flows in a north-northwest direction to Big Sandy Lake where the Big Sandy River originates and then flows in a southwest, south, southwest, and south direction to the south edge of figure 7 (west of center). A trail crosses the drainage divide between Temple Lake to the north and the south oriented Little Sandy Creek (River) valley to the south. The trail makes use of a through valley or pass linking the north-northwest oriented Big Sandy River tributary valley (Rapid Creek on more detailed maps) with the south oriented Little Sandy Creek (River) valley. The through valley or pass floor elevation is between 3500 and 3550 meters. Temple Peak to the west of the through valley or pass rises to more than 3900 meters. Wind River Peak to the east of the through valley or pass rises to more than 4000 meters. These elevations suggest the through valley or pass is at least 350 meters deep. The through valley or pass was eroded by south oriented flood flow moving to the Little Sandy Creek (River) valley. The south oriented flood flow crossed Jackass Pass (seen in figures 5 and 6) to reach the Big Sandy Lake location where flood flow channels diverged with one flood flow channel following the present day north-northwest oriented Big Sandy River  tributary alignment (Rapid Creek) between Temple Lake and Big Sandy Lake and another flood flow channel following the present day southwest and south oriented Big Sandy River alignment. Still other diverging flood flow channels may have been located both west and east of Haystack Mountain and may have also delivered floodwaters to the Little Sandy Creek (River) valley. Headward erosion of a deeper southwest oriented flood flow channel on the southwest and south oriented Big Sandy River alignment beheaded the south-southeast oriented flood flow channels to the actively eroding Little Sandy Creek (River) valley. Floodwaters on north ends of the beheaded flood flow channels reversed flow direction to create the north-northwest oriented Big Sandy River tributary drainage routes. The flood flow reversals were probably aided by crustal warping that was raising the Wind River Range as floodwaters flowed across it.

Detailed map of Big Sandy River-Little Sandy River drainage divide area

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

Figure 8 provides a detailed topographic map of the Big Sandy River-Little Sandy River drainage divide seen in less detail in figure 7. The map contour interval for figure 8 is 40 feet. The Big Sandy River flows in a southwest direction from Big Sandy Lake (straddling the north edge of figure 8-west of center) to the west edge of figure 8 (north of center). Temple Lake is located near the center of figure 8. Rapid Creek flows in a north-northwest direction from Temple Lake to Big Sandy Lake where it joins the southwest oriented Big Sandy River. Temple Peak is located south of Temple Lake and Little Sandy Creek (River) originates east of Temple Peak in the southeast corner of section 32 and then flows in an east and south-southeast direction to the south edge of figure 8 (near southeast corner).  The Little Sandy Trail crosses the Rapid Creek (Big Sandy River)-Little Sandy Creek (River) drainage divide using a through valley or pass in section 32. The through valley or pass floor elevation is between 11,480 and 11,520 feet. Temple Peak to the west rises to 12,972 feet. East Temple Peak to the east rises to 12,590 feet and Wind River Peak further to the east rises to 13,192 feet. These elevations suggest the pass or through valley used by the Little Sandy Trail is 1500 feet deep. Another north to south oriented through valley or pass is located between East Temple Peak and Wind River Peak and is approximately 1300 feet deep. This second through valley links the north-northwest and west-northwest Black Joe Creek valley with the south oriented Little Sandy Creek (River) valley. Diverging and converging south oriented flood flow channels eroded these two parallel through valleys at a time when the Wind River Range did not stand high above regions to the north. There is abundant evidence the valleys in figure 8 have been since modified by alpine glaciation. Glaciation of the high Wind River Range occurred after flood flow across the Wind River Range had ended and after the Wind River Range had emerged as a high mountain range. The alpine glaciers formed in the flood-eroded valleys and glacial erosion modified some of the valley shapes and walls, although the glaciers did not erode new valleys or significantly change the previously formed valley pattern.

North Popo Agie River-Middle Popo Agie River drainage divide area

Figure 9: North Popo Agie-Middle Popo Agie River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 9 illustrates the North Popo Agie River-Middle Popo Agie River drainage divide area east 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 east-west continental divide is shown with a labeled dashed line extending in a southeast and south-southeast direction from the west center edge of figure 9 to the south edge of figure 9 (west half). South and west of the continental divide streams drain to the Pacific Ocean. The North Popo Agie River flows in an east-southeast, east, and northeast direction from the west edge of figure 9 (north of center) to the north edge of figure 9 (east half) and north and east of figure 9 flows to the Popo Agie River and the north oriented Wind-Bighorn River with water eventually reaching the Gulf of Mexico. The Middle Popo Agie River flows in a north-northeast and east direction from the south center edge of figure 9 to the east edge of figure 9 (south half) and east and north of figure 9 flows to the Popo Agie River and north oriented Wind-Bighorn River. Wind River Peak is located in the southwest quadrant of figure 9 and Deep Creek Lakes are located north of Wind River Peak. Deep Creek originates at Deep Creek Lakes and flows in an east and east-southeast direction to join the Middle Popo Agie River at the elbow of capture where the Middle Popo Agie River turns from flowing in a north-northeast direction to flowing in an east direction. A northwest to southeast oriented trail extends from the North Popo Agie River elbow of capture (where it turns from flowing in an east direction to flowing in a northeast direction) to the Deep Creek and Middle Popo Agie River valley. The trail crosses the drainage divide using a through valley or pass with a floor elevation of between 3150 and 3200 meters. Elevations east of the through valley rise to at least 3457 meters and elevations along the continental divide to the west of the through valley rise much higher. These elevations suggest the through valley is at least 250 meters deep. The through valley was eroded by southeast oriented flood flow moving from the east oriented North Popo Agie River headwaters valley to the east oriented Middle Popo Agie River valley. Further east Shoshone Lake is located in a north to south oriented through valley linking the northeast oriented North Popo Agie River valley with the north-northeast and east oriented Middle Popo Agie River valley. The north end of tis north to south oriented through valley is drained by north oriented Shoshone Creek, which originates as a southeast oriented stream. The through valley floor elevation at the Shoshone Creek-Middle Popo Agie River drainage divide is between 2950 and 3000 meters. Mount Arter to the east rises to 3377 meters and elevations to the west rise to 3457 meters suggesting the through valley is at least 377 meters deep. The through valley was eroded by south oriented flood flow probably moving to a south-southwest and south oriented flood flow channel on the present day north oriented Middle Popo Agie River headwaters alignment and then to the actively eroding Sweetwater River valley (see figure 3). Headward erosion of the east oriented Deep Creek-Middle Popo Agie River valley captured the south oriented flood flow and floodwaters on the north end of the beheaded flood flow route reversed flow direction to create the north and north-northeast oriented Middle Popo Agie River headwaters drainage route. Headward erosion of the deeper northeast oriented North Popo Agie River valley next beheaded and reversed the south oriented flood flow channel to create the north oriented Shoshone Creek drainage route. The southeast oriented Shoshone Creek headwaters valley was eroded by southeast oriented flood flow prior to the reversal of flood flow in the Shoshone Creek valley.

Detailed map North Popo Agie River-Deep Creek drainage divide area

Figure 10: Detailed map of North Popo Agie River-Deep Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 10 provides a detailed topographic map of the North Popo Agie River-Deep Creek drainage divide area seen in less detail in figure 9. The map contour interval for figure 10 is 40 feet. The North Popo Agie River flows in an east and north-northeast direction across the northwest corner of figure 10. The Middle Popo Agie River flows in a north-northeast direction from the south edge of figure 10 (east half) to Three Forks Park and then turns to flow in an east direction to the east edge of figure 10 (near southeast corner). Deep Creek originates in the Deep Creek Lakes area near the west edge of figure 10 (south half) and flows in an east-southeast direction to join the Middle Popo Agie River at Three Forks Park. Pinto Park is located in the northeast quadrant of section 13 (west half of figure 10) and is located in a northwest to southeast oriented through valley linking a southeast oriented Deep Creek tributary valley with a northwest oriented North Popo Agie River tributary valley. The through valley floor elevation is between 10,360 and 10,400 feet. Mount Chevo to the east rises to 11,396 feet and elevations just west of figure 10 rise much higher than 11,500 feet. These elevations suggest the through valley is approximately 1000 feet deep. The through valley was eroded by southeast oriented flood flow from the east oriented North Popo Agie River headwaters valley prior to headward erosion of the deeper north-northeast oriented North Popo Agie River valley. Shoshone Basin is located in section 15 (east half of figure 10) and Johnson Meadow is at the south end of Shoshone Basin. Shoshone Creek flows in a southeast direction to Johnson Meadow and then makes an abrupt turn to flow in a north direction through Shoshone Basin and then to Shoshone Lake (straddling the north edge of figure 10). North of figure 10 Shoshone Creek flows to the northeast oriented North Popo Agie River. South of Johnson Meadow are diverging through valleys with the western through valley extending to Three Forks Park and the north-northeast oriented Middle Popo Agie River headwaters valley and the eastern through valley extending in a southeast direction through Upper Hudson Meadow to the east oriented Middle Popo Agie River valley. Between the two diverging through valleys is a high point in section 22 standing about 100 feet above the western through valley floor. The Shoshone Creek-Middle Popo Agie River drainage divide south of Johnson Meadow has an elevation of between 9680 and 9720 feet. Mount Chevo to the west rises to 11,396 feet and Mount Arter to the northeast rises to 11,078 feet. These elevations suggest the north to south oriented Shoshone Creek-Middle Popo Agie River through valley is almost 1400 feet deep. The through valley was eroded by south oriented flood flow first moving to the south oriented Sweetwater River valley on the present day north-northeast oriented Middle Popo Agie River alignment. The south oriented flood flow channel was then captured by headward erosion of the east oriented Middle Popo Agie River valley, which also beheaded and reversed the south-southwest oriented flood flow route on the Middle Popo River headwaters alignment. Headward erosion of the deeper northeast oriented North Popo Agie River valley north of figure 10 next beheaded and reverse Shoshone Creek to create the Shoshone Creek elbow of capture at Johnson Meadow. The Shoshone Creek southeast oriented headwaters drainage route is a relic of a south oriented flood flow route to the former south oriented flood flow channel.

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.