Abstract:

This essay uses topographic map evidence to interpret landform origins in the region between Gooseberry Creek and Cottonwood Creek in the southern Bighorn Basin, Wyoming. Gooseberry Creek and Cottonwood Creek originate in the same general region at the Absaroka Range southeast end and then diverge to flow along separate, but generally east oriented routes in the southern Bighorn Basin and north of the Owl Creek Mountains before turning to flow in southeast directions to join the north oriented Bighorn River as a barbed tributaries. Southeast oriented stream segments or tributaries are common in the study region even though today the Bighorn Basin is drained by a north oriented drainage system. Cottonwood Creek is located south of Gooseberry Creek and through valleys or passes eroded across the drainage divide link Cottonwood Creek tributary valleys with Gooseberry Creek tributary and headwaters valleys. The barbed tributaries, through valleys, and southeast oriented valleys are interpreted to have originated as south and southeast oriented flood flow channels in a large-scale anastomosing channel complex that crossed the region prior to headward erosion of the deeper Cottonwood and Gooseberry Creek valleys and their tributary valleys. At that time the Absaroka Range, the Owl Creek Mountains, and other regional mountain ranges had not yet emerged and floodwaters could freely flow across the region. Floodwaters are interpreted to have been derived from the western margin of a thick North American ice sheet and were flowing in south and southeast direction from western Canada to and across the Bighorn Basin. The regional mountains emerged as floodwaters flowed across them and in time south and southeast oriented floodwaters entering the Bighorn Basin were channeled to a single south oriented flood flow channel being eroded on the present day north oriented Wind River Canyon alignment across the emerging Owl Creek Mountains. The Cottonwood Creek valley and tributary valleys first eroded headward from that south oriented flood flow channel to capture south and southeast oriented flood flow further to the west in the Bighorn Basin. Next headward erosion of the Gooseberry Creek and tributary valleys beheaded flood flow routes to the newly eroded Cottonwood Creek and tributary valleys. Headward erosion of the deep northeast oriented Yellowstone River valley in Montana then beheaded a south oriented flood flow channel to the Bighorn Basin. The Yellowstone River valley was eroding headward from space in the deep “hole” the melting ice sheet had formed and occupied and was now opening up and was capturing the south and southeast oriented flood flow in Montana. Floodwaters on the north end of the beheaded flood flow channel reversed flow direction to create the north oriented Bighorn River drainage route, which then captured south and southeast oriented flood flow still moving west of the actively eroding Yellowstone River valley head.

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 Gooseberry Creek-Cottonwood Creek drainage divide area landform origins in the southern Bighorn Basin, Wyoming. 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 Gooseberry Creek-Cottonwood Creek drainage divide area landform evidence in the southern Bighorn Basin will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm.

Gooseberry Creek-Cottonwood Creek drainage divide area location map

Figure 1: Gooseberry Creek-Cottonwood Creek drainage divide area location map (select and click on maps to enlarge). National Geographic Society map digitally presented using National Geographic Society TOPO software.

Figure 1 provides a location map for the Gooseberry Creek-Cottonwood Creek drainage divide area in the southern Bighorn Basin and illustrates the Wyoming southern Bighorn Basin region. The Yellowstone National Park southeast corner can be seen in the northwest corner of figure 1 and the Absaroka Range extends from the northwest corner of figure 1 to the Owl Creek Mountains. The Yellowstone River flows in a north-northwest direction into the Yellowstone National Park southeast corner and north and west of figure 1 flows in a generally northwest direction into Montana. Once in Montana the Yellowstone River turns to flow in more of an east direction before turning to flow in a northeast direction. The Wind River originates near Togwotee Pass (south of the Yellowstone River headwaters) and flows in a southeast direction to Riverton. At Riverton the Wind River turns to flow in a northeast and north direction to Boysen Reservoir and then through Wind River Canyon to Thermopolis. Wind River Canyon is not labeled in figure 1, but is a deep canyon eroded across the Owl Creek Mountains. At the north end of Wind River Canyon the Wind River name changes to become the Bighorn River. North of Thermopolis the Bighorn River flows in a north, northeast, north, and north-northwest direction to the north edge of figure 1. North of figure 1 the Bighorn River flows in a north and north-northeast direction to join the northeast oriented Yellowstone River. Gooseberry Creek is a labeled east and southeast oriented tributary joining the northeast oriented Bighorn River segment south of Worland. Cottonwood Creek is an unlabeled southeast and east-northeast oriented tributary south of Gooseberry Creek, which joins the northeast oriented Bighorn River segment near the town of Winchester. Grass Creek is an unlabeled east-northeast and east-southeast Cottonwood Creek tributary flowing near the town of Grass Creek. The Gooseberry Creek-Cottonwood Creek drainage divide area investigated in this essay is located west of the Bighorn River, south of Gooseberry Creek, and north of Cottonwood Creek and includes the Gooseberry Creek and Cottonwood Creek headwaters areas in the southeast Absaroka Range.

While today the Bighorn River is a north oriented drainage system the north oriented Bighorn River drainage route originated as a south oriented flood flow channel. Floodwaters were derived from the western margin of a thick North American ice sheet and were flowing from western Canada to and across the present day Bighorn Basin. At that time the Absaroka Range (to the west), the Beartooth and Pryor Mountains (to the north and nor seen in figure 1), the Bighorn Mountains (to the east), and the Owl Creek Mountains had not emerged as mountain ranges and floodwaters could freely flow across what are today high mountain barriers. The mountain ranges emerged as immense melt water floods flowed across them and floodwaters over time were channeled into fewer and fewer channels across the emerging Owl Creek mountain range. In time all south oriented floodwaters entering the Bighorn Basin exited via a south oriented channel on the Wind River Canyon alignment. This south oriented flood flow channel then converged with a southeast oriented flood flow channel on the present day southeast oriented Wind River alignment. The Cottonwood Creek and Gooseberry Creek valleys probably eroded headward from the south oriented flood flow channel on the present day north oriented Bighorn River alignment. The reversal of flow direction in the Bighorn Basin occurred when the deep northeast oriented Yellowstone River valley in Montana (north of figure 1) eroded headward from space in the deep “hole” the melting ice sheet had occupied and was opening up as ice sheet melting occurred and beheaded a south oriented flood flow channel to the Bighorn Basin. Floodwaters on the north end of the beheaded flood flow channel reversed flow direction to create the north oriented Bighorn River drainage route. The newly reversed Bighorn River then captured all south and southeast oriented flood flow in the Bighorn Basin and the southeast oriented flood flow channel on the Wind River alignment. Considerable south and southeast oriented flood flow from west of the actively eroding Yellowstone River valley head was captured and deeply eroded the Wind River Basin south of the Owl Creek Mountains and probably further eroded the Bighorn Basin. In time Yellowstone River valley headward erosion beheaded and reversed all southeast and south oriented flood flow routes to the Yellowstone National Park region to create the northwest oriented Yellowstone River headwaters and ended all flood flow to and across the Bighorn Basin.

Detailed location map for Gooseberry Creek-Cottonwood Creek drainage divide area

Figure 2: Detailed location map Gooseberry Creek-Cottonwood Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 2 provides a more detailed location map for the Gooseberry Creek-Cottonwood Creek drainage divide area in the southern Bighorn Basin. The Bighorn River flows in a north direction from the south edge of figure 2 to Thermopolis and then to the county boundary before turning to flow in a northeast direction to the east edge of figure 2. East and north of figure 2 the Bighorn River flows primarily in a north and north-northeast direction to eventually join the northeast oriented Yellowstone River. Gooseberry Creek originates in the west center area of figure 2 and flows in a north-northeast, and north direction to near Soapy Dale Peak. From near Soapy Dale Peak Gooseberry Creek flows in a northeast, east, and southeast direction to join the northeast oriented Bighorn River as a barbed tributary near the town Neiber (near east edge of figure 2). Cottonwood Creek originates almost at the same place that Gooseberry Creek originates and flows for a short distance in a northeast direction before turning to flow in a southeast, east, and east-northeast direction with a final turn in a southeast direction to join the Bighorn River as a barbed tributary near the town of Winchester. Grass Creek originates near the point where the Cottonwood Creek headwaters turn from flowing in a northeast direction to flowing in a southeast direction and then flows in a northeast direction to near the town of Grass Creek. Grass Creek then flows in an east-southeast direction to the town of Grass Creek and continues to join east-northeast oriented Cottonwood Creek. Note the southeast oriented streams or southeast oriented segments of streams seen in figure 2. South and southeast oriented streams in the southwest corner of figure 2 flow to the southeast oriented Wind River on the south side of the Owl Creek Mountains. Remember the southeast oriented Wind River turns to flow in a north direction to become the Bighorn River a short distance south of Thermopolis. The other southeast oriented streams generally flow to northeast oriented drainage routes, suggesting headward erosion of northeast oriented valleys captured earlier southeast oriented drainage routes. Even though figure 2 lacks contour lines or other topography information and only shows major drainage routes the evidence seen in figure 2 suggests a major drainage reversal has occurred to form the present day north oriented Bighorn River drainage system.

Gooseberry Creek-Cottonwood Creek drainage divide area near the Bighorn River

Figure 3: Gooseberry Cree-Cottonwood Creek drainage divide area near the Bighorn River. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 3 provides a topographic map of the Gooseberry Creek-Cottonwood Creek drainage divide area near the Bighorn River. The Bighorn River flows in a northeast direction from the south edge of figure 3 (east of center) to the east center edge of figure 3. Gooseberry Creek flows in a southeast direction from the north center edge of figure 3 to join the Bighorn River as a barbed tributary near the town Neiber (near east center edge of figure 3). Cottonwood Creek (labeled “Creek” in figure 3) flows in an east-northeast direction from near the southwest corner of figure 3 and near the south center area of figure 3 turns to flow in a southeast direction to join the Bighorn River as a barbed tributary near the town of Winchester. Note other southeast oriented barbed tributaries flowing to the northeast oriented Bighorn River including southeast oriented Little Gooseberry Creek. Also note the southeast oriented tributaries draining to Cottonwood Creek including Chimney Gulch, Lester Draw, Spring Gulch, and Boulder Gulch. These multiple southeast oriented drainage routes in what is today a north oriented drainage system suggest the northeast oriented Bighorn River valley segment eroded headward across multiple southeast oriented flood flow channels such as would be found in a southeast oriented anastomosing channel complex. It is possible the Bighorn River valley was oriented in a southwest direction at the time the southeast oriented flood flow channels were captured. At that time the floodwaters would have been flowing in a south direction to Wind River Canyon and then south across central Wyoming. If so the reversal of flood flow on the Bighorn River alignment to create the north oriented Bighorn River occurred shortly after the capture of the southeast oriented flood flow channels.

Gooseberry Creek-Grass Creek drainage divide area

Figure 4: Gooseberry Creek-Grass Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 4 provides a topographic map of the Gooseberry Creek-Grass Creek drainage divide area west and slightly north of figure 3 and includes an overlap area with figure 3. Gooseberry Creek flows in an east direction near the north edge of figure 4 and east of figure 4 turns to flow in a southeast direction to join the northeast oriented Bighorn River. Coulee Canyon is a southeast and northeast oriented Gooseberry Creek tributary near the northwest corner of figure 4. Grass Creek flows in an east-southeast, east and southeast direction from the west edge of figure 4 (south half) to the south edge of figure 4 (east of center) and south of figure 4 joins east-northeast and southeast oriented Cottonwood Creek. The map contour interval for figure 4 is 50 meters (20 meters along the north edge). Note how broad northwest-to-southeast oriented through valleys on either side of Red Ridge link the Coulee Canyon valley with the Grass Creek valley. A northwest-to-southeast oriented ridge near the center of figure 4 exceeds 1750 meters in elevation while a northwest-to-southeast oriented ridge straddling the west center edge of figure 4 exceeds 1800 meters in elevation. Elevations on the northwest-to-southeast oriented through valley between Red Ridge and the ridge near the center of figure 4 are in the 1600 to 1650 meters range or more than 100 meters lower than elevations on the northwest-to-southeast oriented ridges on either side. This northwest-to-southeast oriented through valley was eroded by southeast oriented flood flow moving to the southeast oriented Grass Creek valley. At that time there were no Coulee Canyon or Gooseberry Creek valleys to the northwest and floodwaters could flow in a southeast direction to what was probably the actively eroding southeast oriented Grass Creek valley. Headward erosion of the deeper east-oriented Gooseberry Creek valley and its Coulee Canyon tributary valley captured the southeast oriented flood flow. Floodwaters on the northwest end of the beheaded flood flow route reversed flow direction to create what are today northwest oriented Coulee Canyon tributary drainage routes. Headward erosion of deep Gooseberry Creek valley next captured the southeast oriented flood flow and beheaded flood flow routes to the newly eroded Coulee Canyon valley.

Grass Creek-Cottonwood Creek drainage divide area

Figure 5: Grass Creek-Cottonwood Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 5 provides a topographic map to illustrate the Grass Creek-Cottonwood Creek drainage divide area south and west of figure 4 and includes a significant overlap area with figure 4. Cottonwood Creek flows in an east-northeast and east direction from the south edge of figure 5 (south of Wagonhound Bench) to the east center edge of figure 5. Grass Creek flows from the north edge of figure 5 in an east-southeast direction from the Grass Creek Basin (“Basin” in figure 5) to make a short northeast jog and then flows in an east and southeast direction to join Cottonwood Creek near the east center edge of figure 5. Spring Gulch is an east and northeast oriented Grass Creek tributary seen near the northwest corner of figure 5. Prospect Creek is the east-southeast, east-northeast, and east-southeast oriented Cottonwood Creek tributary flowing from the west center edge of figure 5. Ilo Ridge is a northwest-to-southeast oriented ridge located just west of the center of figure 5. Note the northwest-to-southeast oriented through valley paralleling the west side of Ilo Ridge, which links the Spring Gulch valley with the Prospect Creek valley The map contour interval for figure 5 is 50 meters and the through valley floor elevation is between 1700 and 1750 meters. Elevations on Ilo Ridge reach more than 1900 meters and elevations of at least 1900 meters can be found west of the through valley. These elevations suggest the northwest-to-southeast oriented through valley is at least 150 meters deep. The through valley was eroded by southeast oriented flood flow prior to headward erosion of Spring Gulch valley (and prior to headward erosion of the Grass Creek and Gooseberry Creek valleys north and west of figure 5). Headward erosion of the Spring Gulch valley from what then the actively eroding Grass Creek valley head captured the southeast oriented flood flow and diverted the floodwaters to the newly eroded Grass Creek valley and ended flood flow in the through valley.

Enos Creek-Grass Creek drainage divide area

Figure 6: Enos Creek-Grass Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 6 illustrates the Enos Creek-Grass Creek drainage divide area west and north of figure 4 and there is an overlap area with figure 4. Gooseberry Creek flows in an east direction from near the northwest corner of figure 6 to near the northeast corner of figure 6. Enos Creek flows in an east and north-northeast direction from the west edge of figure 6 (south half) to join Gooseberry Creek. Grass Creek flows in an east-northeast and north-northeast direction from the south edge of figure 6 (near southwest corner) to near the center of figure 6 and then turns to flow in an east direction to the Grass Creek Basin where it turns to flow in an east-southeast direction to the east edge of figure 6 (south half). Spring Gulch drains in an east-northeast, east, and northeast direction from the south edge of figure 6 to join Grass Creek near the east edge of figure 6. Note how the Enos Creek valley and the Grass Creek valley are linked by through valleys. The map contour interval for figure 6 is 50 meters (except along the north edge where the contour interval is 20 meters). One through valley near the center of figure 6 is oriented in a west-to-east direction and has an elevation of between 1850 and 1900 meters. Elevations north of the through valley rise to more than 2000 meters as do elevations south of the through valley suggesting the through valley is at least 100 meters deep. The through valley was eroded by east or east-southeast oriented floodwaters moving to the Grass Creek valley prior to headward erosion of the northeast oriented Enos Creek valley. The second through valley is located to the south of the first and is oriented in more of a north-to-south direction. The second through valley floor elevation is between 1900 and 1950 meters and elevations on both sides rise to at least 2050 meters suggesting the through valley is at least 100 meters deep. The second through valley was eroded by south oriented flood flow prior to headward erosion of the Enos Creek valley. These two through valleys appear to have been formed by two flood flow channels diverging from a south oriented flood flow channel on the present day north-northeast oriented Enos Creek alignment. Headward erosion of the deep east oriented Gooseberry Creek valley beheaded the south oriented flood flow channel causing floodwaters on the north end of the beheaded flood flow channel to reverse flow direction and to create the north-northeast oriented Enos Creek drainage route, which then eroded headward to capture south and southeast oriented flood flow west of the actively eroding Gooseberry Creek valley head. The Grass Creek Basin appears to be an eroded dome and to be surrounded by hogback ridges. Note how various streams have eroded water gaps across the hogback ridges providing evidence that floodwaters originally flowed on a much higher-level erosion surface. It is also possible and probable that crustal warping that formed the dome occurred as floodwaters crossed the region.

Gooseberry Creek-Enos Creek drainage divide area

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

Figure 7 provides a topographic map of the Gooseberry Creek-Enos Creek drainage divide area west of figure 6 and includes an overlap area with figure 6. Gooseberry Creek flows in a north-northeast and north direction from the south edge of figure 7 (near southwest corner) to near Red Cliff. From the Red Cliff area Gooseberry Creek flows in an east, northeast, east-northeast, and east-southeast direction to the east edge of figure 7 (north half). Elk Creek is a north oriented tributary joining Gooseberry Creek near Wall Rock (near Red Cliff). Middle Creek originates south of Soapy Dale Peak and east of Elk Creek and flows in a northeast direction to join east-southeast oriented Gooseberry Creek segment near the northeast corner of figure 7. Left Hand Creek is northeast, east, and northeast oriented tributary south and east of Middle Creek, which joins Gooseberry Creek near the east edge of figure 7. Enos Creek originates in the southwest quadrant of figure 7 (just east of the word “PARK CO”) and flows in an east and northeast direction to join Gooseberry Creek at the east edge of figure 7. Grass Creek is the northeast oriented stream flowing across the southeast corner of figure 7. The map contour interval for most of figure 7 is 50 meters with a strip near the north edge having a 20 meter contour interval. Many details are lost with the 50-meter contour interval, however several through valleys can still be seen linking the various Gooseberry Creek tributary valleys. One such through valley links the northeast oriented Middle Creek valley with the east oriented segment of the Left Hand Creek valley. The floor elevation of this through valley is between 1950 and 2000 meters with elevations on both sides rising to more than 2050 meters. Perhaps the most impressive through valleys are south of Soapy Dale Peak and link the north oriented Elk Creek valley with the northeast oriented Middle Creek and east oriented Enos Creek headwaters valleys. The Elk Creek-Middle Creek through valley is actually two through valleys with elevations of between 2200 and 2250 meters with Soapy Dale Peak rising to more than 2350 meters to the north and much higher elevations to the south. These elevations suggest the through valleys are more than 100 meters deep. The Middle Creek-Enos Creek through valley has an elevation of between 2250 and 2300 meters with elevations on Leon Baird Peak to the east rising to more than 2350 meters and much higher elevations to the west. These elevations suggest the through valley is at least 50 meters deep. These through valleys provide evidence that south oriented flood flow on the present day north oriented Elk Creek alignment once flowed to the east and northeast oriented Enos Creek valley. Headward erosion of the deep northeast oriented Middle Creek valley then captured the south and southeast oriented flood flow and diverted the floodwaters more directly to the actively eroding Gooseberry Creek valley. At a later time headward erosion of the much deeper Gooseberry Creek valley beheaded the south oriented flood flow channel. Floodwaters on the north end of the beheaded flood flow channel reversed flow direction to create the north oriented Elk Creek drainage route seen today. Soapy Dale Peak and Leon Baird Peak are probably erosional residuals carved by the south and southeast oriented flood flow, which was captured by headward erosion of the Enos and Middle Creek valleys .

Detailed map of Elk Creek-Enos Creek drainage divide area

Figure 8: Detailed map of Elk Creek-Enos 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 Elk Creek-Enos Creek drainage divide area seen in less detail in figure 7. Elk Creek originates in section 27 and flows in a north-northwest and north direction to the north edge of figure 8 (west half) and north of figure 8 joins Gooseberry Creek. Middle Creek originates in section 26 and flows in a north and east-northeast direction to the northeast corner of section 26 and then in a northeast direction to the north edge of figure 8 (near northeast corner). Enos Creek originates near the south edge of figure 8 and flows in a northeast direction into section 35 and then turns to flow in an east direction to the east edge of figure 8. The map contour interval for figure 8 is 40 feet. Soapy Dale Peak in the south half of section 14 (near north edge of figure 8) rises to 7877 feet and Leon Baird Peak in the southeast corner of section 22 rises to 7722 feet. Elevations greater than 8000 feet are found near the south edge of the southwest quadrant of figure 8. In the west half of section 23 and in the northwest corner region of section 26 there are through valleys (or passes) linking the north-northwest oriented Elk Creek headwaters valley with the northeast oriented Middle Creek valley. The section 23 through valley floor elevation is between 7360 and 7400 feet and the section 26 through valley floor elevation is between 7320 and 7360 feet. These elevations and the elevation of Soapy Dale Peak suggest the through valleys are almost 400 feet deep. The through valleys are water eroded valleys and were eroded by south oriented flood flow that had been captured by headward erosion of the northeast oriented Middle Creek valley. The road near the southeast corner of section 26 makes use of a through valley linking the northeast oriented Middle Creek valley with the east oriented Enos Creek valley. The elevation where the road crosses the drainage divide is shown as 7479 feet, which suggests the through valley is almost 300 feet deep. Prior to being captured by headward erosion of the northeast oriented Middle Creek valley the floodwaters were flowing to the east oriented Enos Creek valley. Headward erosion of the Middle Creek valley beheaded the flood flow to the Enos Creek valley. Headward erosion of the deep east oriented Gooseberry Creek valley (north of figure 8) beheaded the south oriented flood flow channel. Floodwaters on the north end of the beheaded flood channel reversed flow direction to create the north-northwest and north oriented Elk Creek drainage route. Crustal warping was probably raising the region as floodwaters were being captured and probably aided in the flood flow reversal process.

Gooseberry Creek-Cottonwood Creek west drainage divide area

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

Figure 9 provides a topographic map of the Gooseberry Creek-Cottonwood Creek west drainage divide area south of figure 7 and includes an overlap area with figure 7. Gooseberry Creek originates near the west edge of figure 9 and flows in a north and north-northeast direction to the north edge of figure 9 (near northwest corner). Cottonwood Creek flows in a northeast and then southeast direction from the west edge of figure 9 (slightly south of center) to the south center edge of figure 9. Grass Creek originates a short distance east of the west center edge of figure 9 and flows in a northeast, east, east-northeast, and north-northeast direction to the north edge of figure 9 (near northeast corner). Note how all three of these diverging drainage routes originate (Gooseberry and Grass Creek) or have a significant direction change near the west center edge of figure 9. The map contour interval for figure 9 is 50 meters and inspection of drainage divides reveals several through valleys or passes linking the diverging drainage routes. For example just east of the Shoshone National Forest boundary a through valley or pass links the south-southeast oriented Otto Creek valley (a Grass Creek tributary) with an unnamed north-northwest oriented Gooseberry Creek tributary valley. The through valley floor elevation is between 2550 and 2600 meters. Elevations on either side rise to more than 2650 meters suggesting the through is at least 50 meters deep. To the south an even deeper through valley links the north-northeast oriented Raspberry Draw valley (a Grass Creek tributary) with the southeast oriented Milk Creek valley. The through valley floor elevation is between 2400 and 2450 meters with elevations on the drainage divide to the east rising to more than 2550 meters and to the west to more than 2700 meters. These elevations suggest this second through valley is at least 100 meters deep. These and similar through valleys crossing the drainage divides provide evidence of south and southeast oriented flood flow channels that crossed the region prior to headward erosion of the much deeper Cottonwood Creek, Grass Creek, and Gooseberry Creek valleys. Headward erosion of the southeast oriented Cottonwood Creek valley captured the south and southeast oriented flood flow first. Next headward erosion of the Grass Creek valley captured the flood flow and beheaded flood flow routes to the newly eroded Cottonwood Creek valley. Floodwaters on north ends of beheaded flood flow routes reversed flow direction to create north oriented Grass Creek drainage routes. Finally headward erosion of the east oriented Gooseberry Creek valley north of figure 9 beheaded the south oriented flood flow channel to the newly eroded Grass Creek valley. Floodwaters on the north end of the beheaded flood flow channel reversed flow direction to create the north oriented Gooseberry Creek headwaters route seen in the northwest corner of figure 9.

Detailed map of Gooseberry Creek-Grass Creek drainage divide area

Figure 10: Detailed map of Gooseberry Creek-Grass 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 Gooseberry Creek-Grass Creek drainage divide area seen in less detail in figure 9. Twin Lakes are located near the center of figure 10. Gooseberry Creek originates in section 19 and flows west of Twin Lakes in a north direction into sections 18 and 7 and then to the north edge of figure 10 (west half). Middle Gooseberry Creek is the north-northeast oriented stream flowing across the northwest corner of figure 10 and north of figure 10 joins Gooseberry Creek. Grass Creek originates in section 20 (south of Twin Lakes) and flows in an east-northeast, northeast, and east direction to the east center edge of figure 10. Cottonwood Creek can just barely be seen at its elbow of capture (where it turns to flow in a southeast direction) along the south edge of the southwest quadrant of figure 10. A through valley or pass (just east of Twin Lakes) links a west oriented Gooseberry Creek tributary valley with an east oriented Grass Creek tributary valley. The map contour interval for figure 10 is 40 feet and the through valley elevation is between 8520 and 8560 feet. Elevations on the drainage divide to the north rise to 8912 feet while drainage divide elevations to the south rise much higher. These elevations suggest the through valley is at least 350 feet deep. The through valley or pass is a water-eroded landform and was eroded by south oriented flood flow on the present day north oriented Gooseberry Creek alignment that was flowing to the what was then the newly eroded Grass Creek valley. Prior to headward erosion of the Grass Creek valley floodwaters were flowing to the Cottonwood Creek valley (south of figure 10). One of the through valleys used by the south oriented floodwaters to reach the Cottonwood Creek valley can be seen near the south center edge of figure 10. South oriented flood flow to the newly eroded Grass Creek valley ended when headward erosion of the east oriented Gooseberry Creek valley (north of figure 10) beheaded the south oriented flood flow channel on the present day north oriented Gooseberry Creek headwaters alignment. Floodwaters on the north end of the beheaded flood flow channel reversed flow direction to create the north oriented Gooseberry Creek headwaters drainage route. Ice sheet related crustal warping was raising the mountains seen in figure 10 as floodwaters flowed across the region. The crustal warping probably contributed significantly to the flood flow reversal in the Gooseberry Creek headwaters 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.