Abstract:

The Red Willow Creek-Blackwood Creek drainage divide area in Perkins, Lincoln, Hayes, Hitchcock, and Red Willow Counties, Nebraska was eroded by massive south-oriented floods. Flood waters were probably derived from a rapidly melting North American ice sheet and flowed south across Nebraska and into Kansas. The east and southeast oriented Republican River valley eroded headward from what was then the newly eroded Kansas River valley to capture south oriented flood waters and divert the flood flow east to the Missouri River valley and then to the south-oriented Mississippi River valley. Evidence of an anastomosing channel complex north of the Republican River valley suggests the southeast oriented Red Willow Creek and Blackwood Creek valleys eroded headward across and along south-oriented flood flow channels. Headward erosion of the Red Willow Creek valley beheaded many south oriented flood flow channels moving flood waters to what were then actively eroding Blackwood Creek tributary valleys and eventually to the actively eroding Blackwood Creek valley head. Flood waters on north ends of beheaded flood flow channels were reversed to flow north to erode what are today north-oriented and barbed Red Willow Creek tributary valleys. Shallow north-south oriented through valleys provide further evidence of former south-oriented flood flow.

Preface:

• The purpose of this essay is to use topographic map interpretation methods to explore Red Willow Creek-Blackwood Creek drainage divide area landform origins in Perkins, Lincoln, Hayes, Hitchcock, and Red Willow Counties, Nebraska, 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 the 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 Red Willow Creek-Blackwood Creek drainage divide area landform origins in Perkins, Lincoln, Hayes, Hitchcock, and Red Willow Counties, Nebraska will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm. This essay is included in the Missouri River drainage basin landform origins research project essay collection.

Red Willow Creek-Blackwood Creek drainage divide area location map

Figure 1: Red Willow Creek-Blackwood 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 Red Willow Creek-Blackwood Creek drainage divide area in Perkins, Lincoln, Hayes, Hitchcock, and Red Willow Counties, Nebraska location map. Nebraska occupies most of the figure 1 map area. Except near the figure 1 west margin Kansas is the state south of Nebraska. Colorado is the state in the figure 1 west margin area located south of the Nebraska Panhandle. North Platte, Nebraska is located near the figure 1 center and is where the southeast-oriented North Platte River joins the northeast and east-northeast oriented South Platte River to form the Platte River. From North Platte the Platte River flows in a southeast direction to Kearney and then in a northeast direction to Grand Island and the figure 1 east edge. East of the figure 1 map the Platte River flows generally in an east direction to join the south-southeast oriented Missouri River. The Republican River is located near the Nebraska south border and flows in an east-northeast direction to Culbertson, McCook, Cambridge, Holbrook, and Arapahoe before turning to flow in an east-southeast direction to Superior, Nebraska. From Superior the Republican River flows generally in a southeast direction into Kansas to join the east-oriented Kansas River, which flows to join the Missouri River at Kansas City, Missouri. At Kansas City the Missouri River turns from flowing in a south-southeast direction to flowing in an east direction to join the south-oriented Mississippi River at Saint Louis, Missouri. Red Willow Creek is a southeast-oriented Republican River tributary located south of North Platte and flows from Wallace to join the Republican River between McCook and Indianola. Hugh Butler Lake is a reservoir flooding the Red Willow Creek valley and is impounded behind Red Willow Dam. Blackwood Creek on figure 1 is the unlabeled southeast-oriented Republican River tributary located immediately west of Red Willow Creek and which flows from near Elsie and Grainton to join the Republican River near Culbertson. Hayes Center is located on the Red Willow Creek-Blackwood Creek drainage divide.

The Medicine Creek-Red Willow Creek drainage divide area and the Platte River-Medicine Creek drainage divide area essays both located immediately east of the Red Willow Creek-Blackwood Creek drainage divide area and can be found under Republican River on the sidebar category list. Hundreds of Missouri River drainage basin landform origins research project essays published on this website collectively present significant evidence for immense south-oriented floods, which flowed across Nebraska and into Kansas. The east-oriented Kansas River valley eroded headward to capture the south-oriented flood flow and to divert the flood waters east to the Mississippi River. The Republican River valley eroded headward from the newly eroded Kansas River valley to capture south-oriented flood flow in western Nebraska and to divert that flood water to the newly eroded Kansas River valley. The Red Willow Creek and Blackwood Creek valleys eroded headward from the newly eroded Republican River valley to capture south-oriented flood flow and to divert the flood waters more efficiently to the newly eroded Republican River valley. Finally the Platte River valley (and its tributary South and North Platte River valleys) eroded headward and beheaded all south-oriented flood flow to what were then the actively eroding Red Willow Creek and Blackwood Creek valleys.

Red Willow Creek-Blackwood Creek drainage divide area detailed location map

Figure 2: Red Willow Creek-Blackwood Creek drainage divide area detailed location map. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 2 provides a somewhat more detailed location map for the Red Willow Creek-Blackwood Creek drainage divide area in Perkins, Lincoln, Hayes, Hitchcock, and Red Willow Counties. Perkins, Lincoln, Chase, Hates, Frontier, Dundy, Hitchcock, and Red Willow are Nebraska county names and county boundaries are shown. The Platte River flows in a southeast direction in the figure 2 northeast corner. The east-northeast oriented South Platte River can just barely be seen in the figure 2 northwest corner. North Platte, Nebraska, where the South Platte and North Platte Rivers meet to form the southeast-oriented Platte River, is located north of the figure 2 north center edge. The Republican River flows in an east-northeast direction from Swanson Lake (a reservoir located along the figure 2 south center edge) across Hitchcock and Red Willow Counties to the figure 2 east edge (south half). Red Willow Creek originates in northeast Perkins County and flows in a southeast direction to Wallace in southwest Lincoln County. From Wallace Red Willow Creek flows in a southeast direction to Hugh Butler Lake and then to join the Republican River at Red Willow, which is located between McCook and Indianola. Blackwood Creek originates west of Grainton in eastern Perkins County and flows in a southeast direction through Hayes County to join the Republican River at Culbertson, which is located in Hitchcock County. Little Blackwood Creek is an important southeast-oriented Blackwood Creek tributary in Hayes County, and is located between Blackwood Creek and Red Willow Creek. Note how drainage routes in Perkins, Chase, Hayes, Dundy, and Hitchcock Counties are generally oriented in a southeast direction and drain to the east-oriented Republican River. While some drainage routes in Perkins County are discontinuous, the drainage pattern suggests multiple southeast-oriented flood flow channels were beheaded by South Platte River valley headward erosion. The discontinuous drainage routes in Perkins County and the large area in Lincoln County without any identifiable drainage routes suggests whatever drainage routes once existed have since been obscured, perhaps by wind-blown sediments. If so, the wind-blown sediments could have been derived from flood deposited sediments, perhaps in an area where flood waters were once temporarily ponded. Flood waters transported large volumes of finer grained sediments including sands, silts, and rock flour and these sediments would have been deposited wherever flood waters were ponded. Western Nebraska has many areas covered with eolian sediments and these sediments probably originated as flood transported and deposited materials.

Red Willow Creek-Blackwood Creek drainage divide area northwest end

Figure 3: Red Willow Creek-Blackwood Creek drainage divide area northwest end. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 3 uses reduced size topographic maps to illustrate the Red Willow Creek-Blackwood Creek drainage divide area northwest end. Wallace is the town located in the figure 3 east center area. Elsie is the town in the figure 3 west center and Grainton is the town midway between Elsie and Wallace in the figure 3 center area. Blackwood Creek originates south of Grainton and flows in a south-southeast direction to the figure 3 south center edge. Red Willow Creek originates north and west of the figure 3 map area and flows from the figure 3 north edge (north of Elsie) in an east direction along the figure 3 north edge and then in a southeast direction to flow north and east of Wallace to the figure 3 east edge. An east-oriented Red Willow Creek tributary originates near Elsie and flows to join Red Willow Creek just north and west of Wallace. Note southeast-oriented tributaries to this east-oriented Red Willow Creek tributary. Dry Creek is a northeast and east-oriented Red Willow Creek tributary located south and east from Wallace and joins Red Willow Creek east of the figure 3 map area. Close study of figure 3 reveals several discontinuous drainage routes, large regions without identifiable drainage routes, low hills, and shallow depressions, all of which suggest the region may be covered with wind-blown sediments, which have obscured at least some surface drainage routes. Drainage routes that can be seen suggest the region was crossed by south and southeast oriented flood flow, which probably flowed across the entire figure 3 map area. The deep Blackwood Creek valley eroded headward into the figure 3 map area to capture at least some of this south-oriented flood flow. At approximately the same time the Red Willow Creek valley and its east-oriented tributary valley (the one that originates near Elsie) eroded headward into the figure 3 map area north of the actively eroding Blackwood Creek valley head. The east-oriented Red Willow Creek tributary captured multiple southeast-oriented flood flow channels that had been moving flood waters in a southeast direction to what was then the actively eroding Blackwood Creek valley head. Figure 4 below provides a detailed map of the Red Willow Creek tributary-Blackwood Creek drainage divide area near Grainton to better illustrate evidence for this capture. Headward erosion of the Red Willow Creek valley north and west of the east-oriented Red Willow Creek tributary valley subsequently captured all south- and southeast-oriented flood flow to the east-oriented Red Willow Creek tributary valley.

Detailed map of Red Willow Creek-Blackwood Creek drainage divide area near Grainton

Figure 4: Detailed map of Red Willow Creek-Blackwood Creek drainage divide area near Grainton. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 4 provides a detailed map of the drainage divide between an east-oriented Red Willow Creek tributary and Blackwood Creek near Grainton and which was seen in less detail in figure 3 above. Grainton is the town located in the figure 4 east center. The southeast oriented stream in sections 20 and 28 flowing to the figure 4 south center edge is a Blackwood Creek headwaters tributary. The east-oriented stream flowing near the figure 4 north edge is an east-oriented Red Willow Creek tributary. Note how the east-oriented Red Willow Creek tributary has northwest-oriented (barbed) tributaries in sections 14, 15, and 16 and has a north-northeast oriented tributary with southeast and northwest oriented tributaries in section 17. Also note shallow through valleys in sections 20, 21, and 22 linking northwest-oriented tributaries to the east-oriented Red Willow Creek tributary with the southeast-oriented valleys draining to the Blackwood Creek valley. The figure 4 map area drainage history can be explained in the context of massive southeast-oriented flood flow moving across the figure 4 map area to what was then the actively eroding southeast-oriented and deep Blackwood Creek valley. Flood waters were probably flowing in a complex of southeast-oriented anastomosing channels.  At that time the east-oriented Red Willow Creek tributary valley did not exist. The east-oriented Red Willow Creek tributary valley then eroded headward across the figure 4 map area and beheaded the southeast-oriented flood flow channels one channel at a time from the east to the west. Flood waters on northwest ends of beheaded flood flow channels reversed flow direction to flow in a northwest direction to the newly eroded east-oriented Red Willow Creek tributary valley. Because flood flow channels were anastomosing (or interconnected) reversed flow in a newly beheaded flood flow channel could capture yet to beheaded flood flow from flood flow channels further to the west. Headward erosion of the east-oriented Red Willow Creek tributary valley in this manner beheaded all flood flow channels supplying flood waters to what had been the actively eroding Blackwood Creek valley. Headward erosion of the Red Willow Creek valley north and west of the figure 4 map area then beheaded all flood flow channels moving flood waters into the figure 4 map area.

Red Willow Creek-Blackwood Creek drainage divide area near the Lincoln-Hayes County border

Figure 5: Red Willow Creek-Blackwood Creek drainage divide area near the Lincoln-Hayes County border. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 5 uses reduced size topographic maps to illustrate the Red Willow Creek-Blackwood Creek drainage divide area south and east of the figure 3 map area and includes overlap areas with figure 3. Blackwood Creek flows in a southeast direction from the figure 5 northwest corner to the figure 5 south edge (west half). Red Willow Creek flows from the figure 5 north center edge area in a southeast direction to the figure 5 southeast corner. The south-southeast-oriented stream originating near the Lincoln County-Hayes County border and located between Blackwood Creek and Red Willow Creek is Little Backwood Creek, which is a Blackwood Creek tributary. Note in the figure 5 north center area just west of the Red Willow Creek valley two northwest-southeast oriented streamlined hills with a northwest-southeast oriented through valley located on the west side. The valleys surrounding those hills are remnants of a southeast-oriented anastomosing channel complex eroded by southeast-oriented flood waters at the time the Red Willow Creek valley was being eroded headward into the figure 5 map area. Narrower streamlined hills adjacent to the Blackwood Creek valley can be seen in the figure 5 northwest quadrant and provide evidence of southeast-oriented anastomosing channels that existed as the Blackwood Creek valley eroded headward into the region. Figure 6 below provides a detailed map of the southeast-oriented anastomosing channels in the Blackwood Creek valley area. Study of the figure 5 map area reveals evidence of the former southeast-oriented anastomosing channel complex can be found throughout the map area. For example, study of shallow valleys north of the Little Blackwood Creek headwaters reveals evidence the Little Blackwood Creek valley was once linked with both the Red Willow Creek valley and the Blackwood Creek valley. These linkages were probably in the form of intertwining southeast-oriented anastomosing flood flow channels, which were beheaded as headward erosion of the deeper Blackwood Creek valley and the deeper Red Willow Creek valley beheaded southeast-oriented flood flow routes to what was then the actively eroding, but shallower Little Blackwood Creek valley.

Detailed map of Blackwood Creek valley

Figure 6: Detailed map of Blackwood Creek valley. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 6 provides a detailed map of the Blackwood Creek valley area seen in less detail in figure 5 above. Blackwood Creek flows from the figure 6 northwest corner area in a southeast direction to the intermittent lake in sections 19 and 30 and then is no longer shown as a surface stream, although the valley continues in a southeast direction to the figure 6 south edge. South of figure 6 Blackwood Creek is again shown as a surface stream. What is particularly interesting about the figure 6 map area is the anastomosing channel complex present. Proceed from west to east across the figure 6 map area to see the various intertwined southeast-oriented valleys. For example, start in the figure 6 northwest quadrant near the figure 6 west edge. Note the north-northwest and north-oriented Blackwood Creek tributary, which joins Blackwood Creek as a barbed tributary near the figure 6 north edge. Note how headwaters of that north-oriented Blackwood Creek tributary are linked in section 23 with headwaters of a south-southeast oriented stream flowing to the figure 6 south edge. The through valley provides evidence south-oriented flood flow in what was once a southeast-oriented flood flow channel on the Blackwood Creek alignment split in the figure 6 northwest corner area with one flood flow channel continuing along the Blackwood Creek alignment and the other flood flow channel proceeding in a south-southeast direction along the alignment defined by the through valley. Subsequently the Blackwood Creek channel was eroded deeper and beheaded flood flow on the south-southeast oriented flood flow channel. Flood waters on the north end of the beheaded flood flow channel reversed flow direction to flow north to what was then the deeper Blackwood Creek flood flow channel. The reversed flood flow eroded the north-northwest oriented Blackwood Creek tributary valley. Note also northwest-southeast oriented streamlined erosional residuals in the Blackwood Creek valley and elsewhere in the figure 6 map area. These streamlined erosional residuals were eroded by southeast-oriented flood flow, which eroded the anastomosing channels or valleys which outline the northwest-southeast oriented hills today. Also note the north-oriented Blackwood Creek tributary in section 25 in the figure 6 southwest quadrant and how that tributary is linked to a south-oriented through valley. The south-southeast oriented Blackwood Creek tributary in section 18 (figure 6 north center area) is also linked to a shallow through valley with a deeper south-southeast oriented valley to the east.

Red Willow Creek-Blackwood Creek drainage divide near Hayes Center

Figure 7: Red Willow Creek-Blackwood Creek drainage divide near Hayes Center. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 7 illustrates the Red Willow Creek-Blackwood Creek drainage divide area near Hayes Center and is located south and east of the figure 5 map area. Hayes Center is the town located near the figure 7 center. Blackwood Creek flows in a south-southeast direction from the figure 7 northwest corner area and near the figure 7 south edge turns to flow in an east and then a southeast direction to the figure 7 south center edge. East of Blackwood Creek is south-southeast oriented Government Canyon, which is located just west of Hayes Center. Government Canyon drains to southeast-oriented Blackwood Creek in the figure 7 south center area. Note how in the figure 7 northwest quadrant a south-southwest oriented Blackwood Creek tributary has eroded headward to behead south-southeast oriented flood flow to was then the actively eroding Government Canyon valley. This intertwining of valleys is further evidence the present day figure 7 drainage network evolved from an anastomosing complex flood flow channels. Continuing east of Hayes Center is south-southeast oriented Little Blackwood Creek and its south-oriented tributary Skunk Creek. Note north-oriented Little Blackwood Creek tributaries just north of the Government Canyon headwaters. The north-oriented Little Blackwood Creek tributary valleys were eroded by reversals of flood flow, which had been moving to what had been the actively eroding Government Canyon valley. Flood flow was reversed when headward erosion of the deep Little Blackwood Creek valley beheaded south-oriented flood flow to the actively eroding Government Canyon valley. Further east note the north-northeast and east oriented Red Willow Creek tributary originating directly north of the south-oriented Skunk Creek headwaters. Red Willow Creek is the southeast and south-southeast oriented stream flowing from the figure 7 north edge (east half) to the figure 7 southeast corner. The Red Willow Creek tributary valley eroded west to capture south-oriented flood flow that had been moving to what had been the actively eroding Skunk Creek valley. Flood waters on the north end of the beheaded flood flow channel reversed flow direction to erode the north-northeast-oriented tributary headwaters valley. Note the shallow north-south through valley linking the north-northeast oriented Red Willow Creek tributary valley with the south-oriented Skunk Creek valley. East of Skunk Creek and west of Red Willow Creek in the figure 7 east center area is Burger Canyon. Note how the south-southeast oriented Burger Canyon headwaters are linked by a shallow north-south oriented through valley with a north-oriented Red Willow Creek tributary. The north-oriented Red Willow Creek tributary valley was eroded by reversed flood flow on the south-oriented flood flow channel which had been moving flood water to what had been the actively eroding Burger Canyon valley.

Detailed map of Red Willow Creek-Skunk Creek drainage divide area

Figure 8 provides a detailed map of the Red Willow Creek-Skunk Creek drainage divide area seen in less detail in figure 7 above. Red Willow Creek is the southeast-oriented stream flowing from Camp Hayes Lake near the figure 8 north edge (east half) to the figure 8 east edge (south half). Skunk Creek is the south-oriented stream in the figure 8 west half originating in section 19 and flowing to the figure 8 south edge. South of figure 8 Skunk Creek flows to south-southeast oriented Little Blackwood Creek, which then flows to southeast-oriented Blackwood Creek. Note how in section 18 there is a north-south oriented through valley linking the south-oriented Skunk Creek valley with a north-oriented Red Willow Creek tributary valley. The north-oriented Red Willow Creek tributary turns to flow in an east direction just north of section 18 and in section 9 turns again to flow in a north direction to join a southeast-oriented Red Willow Creek tributary. Headward erosion of the southeast-oriented Red Willow Creek tributary valley beheaded south-oriented flood flow on the section 9 north-oriented valley segment. Flood waters on the north end of the beheaded flood flow reversed flow direction to flow north to the newly eroded southeast-oriented Red Willow Creek tributary valley. The north-oriented reversed flow captured southeast-oriented flood flow from the west and eroded a valley west to where it beheaded the south-oriented flood flow channel supplying water to what was then the actively eroding Skunk Creek valley. Flood waters on the north end of that beheaded flood flow channel reversed flow direction to erode the north-oriented valley north of the south-oriented Skunk Creek headwaters valley. Also note north-south oriented through valleys linking other north-oriented Red Willow Creek tributary valleys with south-oriented Red Willow Creek tributary valleys. For example in the corner of sections 15, 16, 21, and 22 are through valleys linking a north, north-northeast, and southeast oriented Red Willow Creek tributary valley with a southeast and north-northeast oriented Red Willow Creek tributary valley. The through valleys provide evidence of south-oriented flood flow prior to a reversal of flood flow on the north ends of beheaded south-oriented flood flow routes. Section 29 near the figure 8 south edge shows another such through valley linking a north-oriented valley, which flows to a southeast and north-northeast oriented Red Willow Creek tributary valley, with a south-oriented Little Blackwood Creek tributary valley.

Red Willow Creek-Blackwood Creek drainage divide area near Republican River valley

Figure 9: Red Willow Creek-Blackwood Creek drainage divide area near Republican River valley. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 9 illustrates the Red Willow Creek-Blackwood Creek drainage divide area immediately north of the Republican River valley and is located south and east of the figure 7 map area. McCook, Nebraska is the city located in the figure 9 southeast corner area. Culbertson is the smaller town located in the figure 9 southwest quadrant. The Republican River flows in a northeast direction from the figure 9 southwest corner to Culbertson. At Culbertson the Republican River turns to flow in a southeast and then east direction just south of the figure 9 south edge (near McCook). High Butler Lake is the lake located near the figure 9 north edge (east half) and is a reservoir flooding the Red Willow Creek valley upstream from Red Willow Dam. Red Willow Creek flows in a southeast direction downstream from Red Willow Dam to the figure 9 east center edge. River Canyon is the southeast-oriented valley north of McCook and south of Red Willow Creek, which originates near the abandoned McCook State Airport and drains to the figure 9 east edge (south half). Blackwood Creek is the south-southeast oriented tributary flowing from the figure 9 northwest corner to join the Republican River a short distance east of Culbertson. The southeast-oriented Republican River tributary west of Culbertson is Frenchman Creek. Note the south-southeast oriented Republican River tributaries between Blackwood Creek and the figure 9 east edge and how headward erosion of the southeast-oriented River Canyon and the Red Willow Creek valleys have beheaded what were multiple south-southeast oriented flood flow channels to what was at that time the newly eroded Republican River valley. North-oriented Red Willow Creek and River Canyon tributary valleys were eroded by reversal of flood flow on north ends of the beheaded south-southeast oriented flood flow channels. Headward erosion of the River Canyon valley beheaded south-oriented flood flow to actively eroding south-oriented Republican River tributary valleys in the McCook area. Next Red Willow Creek valley headward erosion beheaded south-oriented flood flow to the newly eroded River Canyon valley and further west to actively eroding south-southeast oriented Republican River tributary valleys. The Blackwood Creek valley was far enough west that Red Willow Creek valley headward erosion did not behead south-oriented flood flow channels to it (at least until reaching the figure 3 map area). Probably all valleys were eroding headward at the same time and the Red Willow Creek valley and Blackwood Creek valleys were eroding headward slightly faster than the valleys between them were eroding headward.

Detailed map of Dry Creek-Blackwood Creek drainage divide area

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

Figure 10 provides a detailed map of the Dry Creek-Blackwood Creek drainage divide area, which is located a short distance north of the figure 9 northwest quadrant. Dry Creek is a Red Willow Creek tributary and originates in the figure 10 northwest quadrant and flows in a southeast, east, northeast, and east direction to join southeast-oriented Red Willow Creek in the figure 10 northeast corner. Red Willow Creek is the southeast-oriented stream which can just barely be seen in the figure 10 northeast corner. The south-oriented stream in sections 17, 20, and 29 is a south-oriented Blackwood Creek tributary, which flows to join southeast-oriented Blackwood Creek south of the figure 10 map area. The south-oriented stream in section 28 south of the figure 10 map area joins the south-oriented stream in section 29. Note the north-south oriented through valleys in sections 17 and 21 linking the east oriented Dry Creek valley with the south-oriented Blackwood Creek tributary valleys. Three north-south through valleys are easy to identify and provide evidence of at least three south-oriented flood flow channels moving flood water to what was then the actively eroding Blackwood Creek valley. Headward erosion of the east , northeast, and east oriented Dry Creek valley beheaded the three south oriented flood flow channels and diverted the flood water east and northeast to the newly eroded Red Willow Creek valley. Flood waters on north ends of the beheaded flood flow channels reversed flow direction to flow north to erode the north oriented Dry Creek tributary valleys and to create the Dry Creek-Blackwood Creek drainage divide. Note in the figure 10 east half how north-oriented Dry Creek tributary valleys are linked by shallow through valleys with southeast-oriented tributary valleys to a northeast-oriented Red Willow Creek tributary valley. Headward erosion of those eastern north-oriented Dry Creek tributary valleys was probably aided by the capture of yet to be beheaded south-oriented flood flow from flood flow channels further west in the figure 10 map area. Dry Creek valley headward erosion beheaded south-oriented flood channels one channel at a time and proceeded from east to the west. Flood flow channels were anastomosing or interconnected, meaning reversed flood flow in a newly beheaded flood flow channel could capture yet to be beheaded flood flow from flood flow channels further to the west. These captures of yet to be beheaded flood flow resulted in complex flood flow movements, which account for different valley orientations.

Additional information and sources of maps

This essay has only provided a sample of the drainage divide evidence supporting the “thick ice sheet that melted fast” geomorphology paradigm. Many additional examples could be provided, especially by using more detailed topographic maps. Readers are encouraged to look at mosaics of detailed topographic maps to see the abundance of supporting data. Maps used in this study were created by the United States Geological Survey and can be purchased in hard copy from the United States Geological Survey or from dealers offering United States Geological Survey maps. Hard copy maps can also be observed at United States Geological Survey map depositories located in major research libraries and elsewhere throughout the United States and in other countries. Illustrations used in this essay were created using National Geographic Society TOPO software and digital data. National Geographic Society digital maps can be purchased from the National Geographic Society or from dealers offering National Geographic Society digital maps.