A geomorphic history based on topographic map evidence
Abstract:
Red Willow Creek and Medicine Creek are southeast-oriented Republican River tributaries located primarily in Lincoln, Hayes, Frontier, and Red Willow Counties in southwest Nebraska. The Red Willow Creek-Medicine Creek drainage divide area was eroded by immense south-oriented floods, which were probably derived from a rapidly melting thick North American ice sheet. The east and southeast oriented Republican River valley eroded headward from what was then the newly eroded Kansas River to capture the south-oriented flood flow and to divert flood waters east and southeast. Southeast and south-southeast oriented tributary valleys eroded headward or north from the newly eroded Republican River valley along and across south oriented anastomosing flood flow channels. The Medicine Creek valley was one such valley and beheaded south oriented flood flow channels to what were then several south-southeast oriented and actively eroding Republican River and Red Willow Creek tributary valleys further to the west. The Red Willow Creek valley, which is located west of the Medicine Creek valley, eroded headward fast enough Medicine Creek valley headward erosion did not behead all south-oriented flood flow routes to it. Headward erosion of the east-oriented Platte River valley beheaded all south-oriented flood flow to the Red Willow Creek-Medicine Creek drainage divide area.
Preface:
Introduction:
- The purpose of this essay is to use topographic map interpretation methods to explore Medicine Creek-Red Willow Creek drainage divide area landform origins in Lincoln, Hayes, Frontier, 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 Medicine Creek-Red Willow Creek drainage divide area landform origins in Lincoln, Hayes, Frontier, 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.
Medicine Creek-Red Willow Creek drainage divide area location map
Figure 1: Medicine Creek-Red Willow 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 Medicine Creek-Red Willow Creek drainage divide area in Lincoln, Hays, Frontier, and Red Willow Counties, Nebraska location map. Nebraska occupies much of the figure 1 map area with the Colorado northeast corner located in the figure 1 southwest corner and a strip of northwest Kansas located south of Nebraska and east of Colorado. The Platte River originates at the confluence of the North Platte River and South Platte River at North Platte, Nebraska (near the figure 1 center) and flows in a southeast direction to Kearney, Nebraska and then in a northeast direction to the figure 1 east center edge. The North Platte River flows in a southeast and east direction from the figure 1 west edge (north half) to North Platte. The South Platte River flows in a northeast direction from the figure 1 west edge to the Colorado northeast corner and then in an east-northeast direction to join the North Platte River at North Platte. The Republican River originates in Colorado and flows in a northeast direction to the Nebraska southwest corner and then flows in an east-northeast direction to Holbrook and Arapahoe, Nebraska. At Arapahoe the Republican River turns to flow in a southeast and then east direction to Superior, Nebraska near the figure 1 southeast corner. East and south of the figure 1 map area the Republican River flows in a southeast direction to join the east-oriented Kansas River. Red Willow Creek is a labeled southeast-oriented Republican River tributary located south of North Platte and flows from northwest of Wallace in a southeast direction to join the Republican River between McCook and Indianola, Nebraska. Medicine Creek is the unlabeled southeast-oriented Republican River tributary located east of Red Willow Creek. Medicine Creek originates northwest of Wellfleet (located south of North Platte) and flows in a southeast direction to Maywood, Curtis, and Stockville before joining the Republican River near Cambridge, Nebraska. Maps and discussions in this essay focus on the region between Red Willow Creek and Medicine Creek. The Platte River-Medicine Creek drainage area essay described the region located east of the drainage divide area investigated here and can be found listed under Platte River (NE) or Republican River on the sidebar category list. Hundreds of Missouri River drainage basin landform origins research project essays published on this website collectively provide significant evidence for massive south-oriented floods, which flowed across Nebraska and into Kansas. Flood waters were probably derived from a rapidly melting North American ice sheet. Flood waters in the Red Willow Creek-Medicine Creek drainage divide area were first captured by headward erosion of the deep Republican River valley, which eroded headward from what was then the newly eroded Kansas River valley. The Medicine Creek and Red Willow Creek valleys then eroded headward from the newly eroded Republican River valley. Flood flow to what were the actively eroding Medicine Creek and Red Willow Creek valleys and tributary valleys were beheaded by headward erosion of the Platte River valley, which eroded headward from what was then the newly eroded south-southeast oriented Missouri River valley, located east of the figure 1 map area.
Medicine Creek-Red Willow Creek drainage divide area detailed location map
Figure 2: Medicine Creek-Red Willow Creek drainage divide area detailed location map. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
Figure 2 provides a more detailed location map for the Medicine Creek-Red Willow Creek drainage divide area in Lincoln, Hayes, Frontier, and Red Willow Counties, Nebraska. Lincoln, Dawson, Hayes, Frontier, Gosper, Hitchcock, Red Willow, and Furnas are Nebraska county names and county boundaries are shown. The Platte River flows in a southeast direction from the figure 2 north center edge to the figure 2 east center edge area. The Republican River flows in an east-northeast direction across Hitchcock and Red Willow Counties and into Furnas County, where at Arapahoe it turns to flow in a southeast direction to the figure 2 southeast corner. Red Willow Creek originates west of the figure 2 map area and flows in a southeast direction to Wallace (located in the Lincoln County southwest corner) and then into and across eastern Hayes County to enter Hugh Butler Lake located in southwest Frontier County. Hugh Butler Lake is a reservoir impounded behind Red Willow Dam. From Red Willow Dam Red Willow Creek flows in a southeast direction into Red Willow County and to join Republican River near Red Willow. Spring Creek located in western Frontier County is a south-southeast oriented Red Willow Creek tributary. Medicine Creek originates near Somerset in southern Lincoln County (east of Wallace) and flows in a southeast direction to Wellfleet, Maywood, Curtis, and Stockville before joining the Republican River near Cambridge in the Furnas County northwest corner. Harry Strunk Lake in southern Frontier County is a reservoir impounded behind Medicine Creek Dam. Brushy Creek in northwest Frontier County (and southern Lincoln County) and Cedar Creek near Stockville are important Medicine Creek tributaries. Named figure 2 south-southeast oriented Republican River tributaries between Red Willow Creek and Medicine Creek are Coon Creek, Dry Creek, and Stevenson Canyon. Note the south, south-southeast, and southeast oriented Republican River tributaries across the figure 2 south margin. The south-oriented tributary valleys eroded headward from what was at one time the actively eroding Republican River valley head as the deep Republican River valley eroded headward across the figure 2 map area to capture massive south-oriented flood flow. Generally the south-oriented tributary valleys eroded headward in sequence, from east to west. Republican River valley headward erosion was probably eroding at a faster rate than the rate of tributary valley erosion, which meant south-oriented Republican River tributary valleys west of the Cambridge area (where Medicine Creek joins the Republican River) were able to erode headward before Medicine Creek valley (and Medicine Creek tributary valley) headward erosion beheaded south-oriented flood flow channels supplying flood water to those south-actively eroding Republican River (and Red Willow Creek) tributary valleys. Also note north-oriented Republican River tributaries. The north-oriented Republican River tributary valleys were eroded by reversals of flood flow on north ends of beheaded south-oriented flood flow channels.
Northwest end of Medicine Creek-Red Willow Creek drainage divide area
Figure 3: Northwest end of Medicine Creek-Red Willow Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
Figure 3 uses reduced size maps to illustrate the northwest end of the Medicine Creek-Red Willow Creek drainage divide area in southern Lincoln County. Wallace is the town located just north of the figure 3 west center edge area. Red Willow Creek flows from west of the figure 3 map area to Wallace and then in a southeast direction to the figure 3 south edge. Somerset is the much smaller town located in the figure 3 east center area and Dickens is the small town located between Wallace and Somerset. Medicine Creek originates northwest of Somerset and flows in a southeast direction from Somerset to the figure 3 east edge. The east-oriented Medicine Creek tributary located south of Somerset is Little Medicine Creek. Other than Red Willow Creek, Medicine Creek, and Little Medicine Creek the figure 3 map area is devoid of identifiable drainage routes. The region appears to be an almost featureless plain and to probably be covered with a veneer of wind deposited sediments.The Medicine Creek and Little Medicine Creek valleys appear to have been eroded as deep valleys into this featureless plain, although Red Willow Creek does not appear to have eroded a deep valley, at least in the figure 3 map area. As we progress south and east along the Red Willow Creek-Medicine Creek drainage divide area remember this featureless upland plain. Prior to Republican River valley headward erosion the entire Red Willow Creek-Medicine Creek drainage divide area looked like this plain, although at that time massive south-oriented floods were moving across the region. It is possible flood waters were temporarily ponded in this region and deposited sediments which cover the entire figure 3 surface. These flood deposited sediments may be the source of wind-blown materials, which probably cover the region. Headward erosion of the Medicine Creek and Red Willow Creek valleys into the figure 3 map ended when Platte River valley headward erosion north of the figure 3 map area beheaded all flood flow routes to the figure 3 map area. The figure 3 landscape has changed little since that time.
Medicine Creek-Brushy Creek drainage divide area
Figure 4: Medicine Creek-Brushy Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
Figure 4 illustrates the Medicine Creek-Brushy Creek drainage divide area south and east of the figure 3 map area. Wellfleet is the town located near the figure 4 north edge. Maywood is the town located in the figure 4 southeast quadrant. Medicine Creek flows from Wellfleet in a southeast direction to Maywood and then to the figure 4 east edge (near southeast corner). The east-oriented tributary joining Medicine Creek near the figure 4 southeast corner is Brushy Creek. North Brushy Creek originates just north of the Lincoln County-Frontier County line and flows in a southeast direction to join South Brushy Creek south of Maywood. South Brushy Creek originates near the Hayes County-Frontier County line and flows in an east direction to join North Brushy Creek and then to flow in an east direction to join Medicine Creek. Note how South Brushy Creek has several southeast oriented tributaries. Note also how North Brushy Creek also has southeast and south oriented tributaries and several north and northeast oriented tributaries. Further note how the north and northeast oriented North Brushy Creek tributary valleys are linked by shallow through valleys with the southeast-oriented South Brushy Creek tributary valleys. In addition note how the south and southeast oriented North Brushy Creek tributary valleys area linked by shallow through valleys with the southeast oriented Medicine Creek valley to the north. The shallow through valleys provide evidence of a south- and/or southeast-oriented anastomosing channel complex which crossed the present day Medicine Creek drainage basin (the eroded area in figure 4). Probably the anastomosing channel complex was not limited to the figure 4 eroded area, but had developed across the entire figure 4 map area. Headward erosion of the deep Medicine Creek valley and tributary valleys was eating into the featureless upland plain area and was halted when Platte River valley headward erosion beheaded the south-oriented flood flow. The deep Medicine Creek valley and tributary valleys such as the South and North Brushy Creek valleys and their tributary valleys probably eroded headward along what were then channels in what was then the higher elevation anastomosing channel complex. The South Brushy Creek valley eroded headward first and North Brushy Creek headward erosion then beheaded south-oriented flood flow to the newly eroded South Brushy Creek valley. North-oriented North Brushy Creek tributary valleys probably were eroded by reversals of flood flow on north ends of beheaded flood flow channels. Medicine Creek valley headward erosion then beheaded flood flow channels supplying flood water to what were then the actively eroding North Brushy Creek valley and tributary valleys.
Brushy Creek-Cedar Creek drainage divide area
Figure 5: Brushy Creek-Cedar Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
Figure 5 illustrates the Brushy Creek-Cedar Creek drainage divide area south and east of the figure 4 map area and includes a thin strip of overlap area with figure 4. Curtis is the town located near the figure 5 north edge (east half). Note the railroad line located just south of Curtis. The railroad line follows Medicine Creek, which is the southeast, east, and southeast oriented stream in the figure 5 northeast corner area. Cottonwood Canyon is a north-northeast and north oriented Medicine Creek tributary joining Medicine Creek at approximately the location where east-oriented Brushy Creek also joins Medicine Creek. Brushy Creek is the east oriented Medicine Creek tributary flowing along the figure 5 north center edge and South Brushy Creek is the east-oriented Brushy Creek tributary joining Brushy Creek near the Gaging Station located near the figure 5 north edge (by the north-south highway). Elkhorn Canyon is a southeast, northeast, and north oriented South Brushy Creek tributary located in the figure 5 northwest quadrant. Frazier Creek is an interesting north, east, northeast, southeast, and north-northwest Brushy Creek tributary located west and south of Cottonwood Canyon. Note the large number of north-oriented Frazier Creek tributary valleys. Those north-oriented Frazier Creek tributary valleys are linked by shallow through valleys with south oriented Red Willow Creek and Republican River tributary valleys. Cedar Creek is the north and southeast oriented stream in the figure 5 southeast quadrant flowing to the figure 5 southeast corner. Note how southeast oriented Cedar Creek tributaries are linked by shallow through valleys with northwest and north oriented Frazier Creek tributary valleys and also with the north oriented Cottonwood Canyon valley. Note further north-oriented Cedar Creek headwaters and how the north oriented valleys are linked by shallow through valleys with south-oriented valleys. The western north-oriented Cedar Creek headwaters valley is linked to a south oriented Red Willow Creek tributary valley. The eastern north-oriented Cedar Creek headwaters valley is linked to a south oriented Coon Creek tributary valley (Coon Creek flows in a south-southeast direction directly to the Republican River). What has happened here is headward erosion of the southeast oriented Cedar Creek valley beheaded south oriented flood flow to actively eroding south oriented Republican River and Red Willow Creek tributary valleys. Flood waters on north ends of beheaded flood flow channels reversed flow direction to flow north and to erode the north-oriented Cedar Creek headwaters valleys. Medicine Creek valley headward erosion next beheaded south-oriented flood flow to the newly eroded Cedar Creek valley. Flood waters on north ends of beheaded flood channels reversed flow direction to erode the north and north-northwest oriented Cottonwood Canyon and Frazier Creek valleys. Reversed flood flow in the north-northwest oriented Frazier Creek valley captured significant flood flow from south-oriented flood flow channels further to the west, which resulted in development of the complex Frazier Creek valley route seen today.
Red Willow Creek-Brushy Creek drainage divide area
Figure 6 uses reduced size maps to illustrate the Red Willow Creek-Brushy Creek drainage divide area west and south of the figure 4 map area and includes overlap areas with figures 4 and 5. Maywood is the town located in the figure 6 northeast quadrant. Medicine Creek is the south-southeast oriented stream flowing across the figure 6 northeast corner. North Brushy Creek is the southeast-oriented stream flowing from the figure 6 north edge to join east-oriented South Brushy Creek near the Gaging Station located south from Maywood. Elkhorn Canyon is located south of South Brushy Creek and has southeast-oriented headwaters before turning to drain in a northeast and north direction to South Brushy Creek. Frazier Creek is located south of Elkhorn Canyon and flows to the figure 6 east edge. Red Willow Creek flows in a south-southeast direction in the figure 6 southwest quadrant. Spring Creek is a south-oriented Red Willow Creek tributary originating near the Elkhorn Canyon headwaters area and flowing south to the figure 6 south center edge. Other south-oriented drainage routes in the figure 6 southeast quadrant flow to southeast-oriented Red Willow Creek. Note how Red Willow Creek has eroded a deep valley into the upland surface, although the eroded area surrounding the Red Willow Creek valley is narrower than the eroded surrounding the Medicine Creek valley. The upland surface between the Red Willow Creek and the Brushy Creek (Medicine Creek) valleys lacks any evidence of a surface drainage pattern and may be covered with a veneer of wind-blown sediments, which obscure prior drainage routes. What has probably happened here is south-oriented flood flow has deeply eroded the figure 6 east half, but was beheaded before the figure 6 west half could be deeply eroded. Prior to headward erosion of the Medicine Creek-Brushy Creek valley system into the figure 6 map area (northeast quadrant) flood flow channels were eroding south-oriented tributary valleys north from what was then the newly eroded southeast-oriented Red Willow Creek valley located south of the figure 6 southeast quadrant. Headward erosion of the Medicine Creek-Brushy Creek valley system as described in the figures 4 and 5 discussion beheaded (and in some cases reversed) south-oriented flood flow routes. Headward erosion of the Platte River valley north of the Red Willow Creek-Medicine Creek drainage divide area apparently beheaded south-oriented flood flow routes across the figure 6 west half before south-oriented Red Willow Creek tributary valleys could erode north.
Cedar Creek-Dry Creek drainage divide area
Figure 7: Cedar Creek-Dry Willow Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
Figure 7 illustrates the Cedar Creek-Dry Creek drainage divide area south and east of the figure 5 map area. Medicine Creek flows in a southeast direction from the figure 7 north center edge area to Harry Strunk Lake located in the figure 7 southeast corner. Cedar Creek flows in a southeast direction before turning to flow in a north-northeast direction and then an east direction before finally turning to flow north to join southeast oriented Medicine Creek as a barbed tributary near the figure 7 north center edge. Note how Cedar Creek has north-oriented tributaries. North-oriented Cedar Creek tributaries south of the north-northeast oriented Cedar Creek valley segment are linked by shallow north-south through valleys with south oriented tributaries to south-southeast oriented Dry Creek (located in the figure 7 south center area). South of the figure 7 map area Dry Creek flows in south-southeast direction to the east-oriented Republican River. The labeled south-southeast oriented Dry Creek valley is linked by a shallow through valley to north-northeast oriented headwaters of Walnut Creek. Walnut Creek flows in a north-northeast, east, north, and northeast direction to join southeast oriented Medicine Creek as a barbed tributary. Figures 8 and 9 below provide detailed map of the Cedar Creek-Walnut Creek and Walnut Creek-Dry Creek drainage divide areas to better illustrate the through valleys linking what are today independent drainage basins. Note the shallow north-south oriented through valley linking the Walnut Creek valley with an unnamed southeast, north, and northeast-oriented Medicine Creek tributary located further to the south and east. That unnamed tributary also joins Medicine Creek as a barbed tributary. A close look at figure 7 reveals other shallow north-south oriented through valleys linking the southeast-oriented Cedar Creek valley segment with south- and southeast-oriented Republican River tributary valleys to the south. These shallow through valleys provide evidence of south-oriented flood flow that existed prior to headward erosion of the deep Medicine Creek valley and its tributary valleys. The north-oriented (barbed) Medicine Creek tributary valleys were eroded as a result of the reversal of flood flow on north ends of beheaded south-oriented flood flow routes. The reversed flood flow eroded north-oriented valleys or valley segments so as to reach the newly eroded and deeper Medicine Creek valley. The north-oriented Medicine Creek tributary valleys formed in sequence from the southeast to the northwest as headward erosion of each tributary valley beheaded and reversed flood flow moving to the previously eroded tributary valley.
Detailed map of Cedar Creek-Walnut Creek drainage divide area
Figure 8: Detailed map of Cedar Creek-Walnut Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
Figure 8 provides a detailed map of the Cedar Creek-Walnut Creek drainage divide area seen in less detail in figure 7 above. Cedar Creek flows in a north-northeast direction along the north half of the figure 8 west edge and then turns to flow in an east-northeast and east-southeast direction to section 10 along the figure 8 north edge and finally turns to flow in a northeast direction to the figure 8 north edge. Walnut Creek flows in a north-northeast direction in section 28 in the figure 8 south center area and then turns to flow in an east direction before turning again to flow north across the section 23 west margin and finally turns to flow in a northeast direction to the figure 8 northeast corner. Note in section 21 a through valley linking and north-northwest and north oriented Cedar Creek tributary valley with the Walnut Creek elbow of capture where north-northeast oriented Walnut Creek turns to flow in an east direction. That through valley provides evidence the north-northeast oriented Walnut Creek headwaters valley segment originated as a south-oriented flood flow channel (with a floor at least as high as the through valley floor). Headward erosion of the east-oriented Walnut Creek valley beheaded the south-oriented flood flow and flood waters on the north end of the beheaded flood flow channel reversed flow direction to flow north to the newly eroded east-oriented Walnut Creek valley. Next headward erosion of the east-southeast oriented Cedar Creek valley beheaded south-oriented flood flow to the newly eroded Walnut Creek valley. Flood waters on the north end of the beheaded flood flow route reversed flow direction to flow north and eroded the north-oriented Cedar Creek tributary valley. My description has simplified the situation because at the time flood waters were moving in multiple interconnected flood flow channels. Some of the other channels can be identified by other shallow through valleys linking the Cedar Creek valley system with the Walnut Creek valley system. Note other through valleys in sections 15, 21, 20, 29. Yet to be beheaded flood waters from flood flow channels west of the actively eroding Cedar Creek valley head were captured by reversed flood flow in the Walnut Creek valley and even perhaps on some of the more eastern north-oriented Cedar Creek tributary alignments, and large volumes of captured yet to be beheaded flood flow helped erode the north-oriented Walnut Creek and Cedar Creek tributary valleys.
Detailed map of Walnut Creek-Dry Creek drainage divide area
Figure 9: Detailed map of Walnut Creek-Dry Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
Figure 9 provides a detailed map of the Walnut Creek-Dry Creek drainage divide area south of the figure 8 map area and represents another region seen in less detail in figure 7 above. Walnut Creek originates in section 5 near the figure 9 center and flows in a north-northeast direction to the figure 9 north edge. The Walnut Creek route north of figure 9 is seen in figure 7. North-oriented figure 9 drainage routes west of Walnut Creek are Cedar Creek tributaries. Dry Creek originates in section 4 and flows south into section 9 and then to the figure 9 south edge. South of figure 9 Dry Creek flows to the Republican River. All other figure 9 south-oriented valleys drain to Dry Creek. Note how in sections 3, 4 and 5 north-oriented Walnut Creek valley and tributary valleys are linked by through valleys with the south-oriented Dry Creek valley and tributary valleys. Also note the north-south oriented through valleys in sections 5 (west margin), 6, and 1 linking north-oriented Cedar Creek tributary valleys with south-oriented Dry Creek tributary valleys. These through valleys provide evidence of multiple south-oriented flood flow channels moving water to what was once the actively eroding Dry Creek valley system, which had eroded headward from what was then the newly eroded east-oriented Republican River valley. At that time the north-oriented Walnut Creek valley did not yet exist, the Cedar Creek valley did not yet exist, and the Medicine Creek valley did not exist north of the figures 7,8, and 9 map areas.What figure 9 evidence is showing is evidence of a south-oriented anastomosing channel complex, which once moved vast quantities of south-oriented flood water to what was then the newly eroded Republican River valley. Headward erosion of the southeast-oriented Medicine Creek valley captured those south-oriented flood flow channels in sequence from the southeast to the northwest and diverted the flood waters more directly to the newly eroded Republican River valley. Flood waters on north ends of beheaded flood flow channels reversed flow direction to develop north-oriented Medicine Creek tributary valleys such as those seen in figure 9. As previously discussed these reversed flood flow movements were complex and resulted in the development of what appear to complicated drainage routes that flow to southeast-oriented Medicine Creek as barbed tributaries.
Republican River valley between Red Willow Creek and Medicine Creek
Figure 10: Republican River valley between Red Willow Creek and Medicine Creek. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
Figure 10 illustrates the Republican River valley between Red Willow Creek and Medicine Creek and is located south of the figure 7 map area. The Republican River flows in an east-northeast direction from the figure 10 southwest corner to the figure 10 east edge. The town located in the Republican River valley near the figure 10 east edge is Cambridge, Nebraska. Medicine Creek is the south-southeast oriented stream joining the Republican River just east of Cambridge (and the figure 10 east edge). Medicine Creek Dam is located in the figure 10 northeast corner and the south end of Harry Strunk Lake is immediately upstream from the dam. Red Willow is the place-name near the figure 10 southwest corner and Red Willow Creek flows in a southeast direction from the figure 10 west edge (south half) to join the Republican River near Red Willow. The town located in the Republican River valley downstream from Red Willow is Indianola and Bartley is the town located between Indianola and Cambridge. Stevenson Canyon is the south-southeast oriented tributary joining the Republican River just east of Bartley. Dry Creek is the south, southeast, and south-southeast oriented tributary joining the Republican River just west of Bartley. Coon Creek is the south-southeast oriented tributary joining the Republican River at Indianola. The Republican River valley eroded headward across the figure 10 map area to capture massive south-oriented flood flow which was moving across the region on a topographic surface at least as high as the featureless upland surface seen in figure 3 above. At that time the Platte River valley north of the Red Willow Creek-Medicine Creek drainage divide area did not exist, and for that matter none of the Missouri River tributary valleys north of the Republican River existed. As the actively eroding deep Republican River valley head eroded headward across the figure 10 map area south-southeast oriented tributary valleys began to erode north along the south-oriented flood flow channels. At the same time flood waters on north ends of beheaded flood flow routes reversed flow direction to flow north to the newly eroded and deep Republican River valley. These newly reversed and now north-oriented flood waters eroded the north-oriented Republican River tributary valleys. As the deep Medicine Creek valley eroded in a north-northwest direction it began to behead flood flow routes to what were then slightly shorter Republican River tributary valleys located further to the west. As seen in figures above reversed flood flow on north ends of the beheaded south-oriented flood flow routes developed north, north-northeast, east, are northeast oriented Medicine Creek tributary systems, which eventually beheaded south-oriented flood flow to what were then actively eroding south-oriented valleys west of Medicine Creek except to the main Red Willow Creek valley head. Medicine Creek tributary valleys did behead south-oriented flood flow to some south-oriented Red Willow Creek tributary valleys, but the present day Red Willow Creek valley had by that time eroded far enough west that it was still able to capture south oriented flood flow and erode further to the northwest.
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.
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