Abstract:

The Osage River-Weaubleau Creek drainage divide in St Clair, Benton, and Hickory Counties is bounded on the east by the north-oriented Pomme de Terre River, on the west by north, northwest, and north oriented Weaubleau Creek, and on the north by the east-oriented Osage River, and is drained primarily by north-oriented streams. North-oriented valleys in the St Clair, Benton, and Hickory County area were eroded during a massive reversal of an immense south-oriented flood. The south-oriented flood flow was derived from a rapidly melting North American ice sheet and prior to being reversed was flowing south to south-oriented tributary valleys actively eroding headward from what was then the newly eroded southeast-oriented White River valley. Headward erosion of the deep east-oriented Missouri River-Osage River valley triggered the massive flood flow reversal by beheading south-oriented flood flow routes in sequence from east to west. Flood waters on north ends of newly beheaded flood flow routes reversed to erode north-oriented valleys which captured flood flow still moving south on flood flow routes west of the actively eroding Osage River valley head. Osage River and Pomme de Terre River incised meanders probably originated as deep valleys were eroded headward across previously eroded, but much shallower, flood flow channels. Evidence supporting this flood origin interpretation includes positions and orientation of present day valleys and through valleys eroded across present day drainage divides.

Preface:

The following interpretation of detailed topographic map evidence is provided as evidence in the Missouri River drainage basin landform origins research project, which is compiling similar evidence for all major drainage divides contained within the Missouri River drainage basin and for all major drainage divides with and within certain adjacent drainage basins. The research project is interpreting evidence in the context of a previously unexplored geomorphology paradigm, which is briefly described in the introduction below. Project essays available at this site may be found by selecting desired Missouri River tributaries and/or states from this essay’s sidebar category list.

• The purpose of this essay is to use topographic map interpretation methods to explore Osage River-Weaubleau Creek drainage divide area landform origins in St Clair, Benton, and Hickory Counties, Missouri, 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 topographic map evidence in the Osage River-Weaubleau Creek drainage divide area in St Clair, Benton, and Hickory Counties, Missouri will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm.

Osage River-Weaubleau Creek drainage divide area location map

Figure 1: Osage River-Weaubleau 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 Osage River-Weaubleau Creek drainage divide area in St Clair, Benton, and Hickory Counties, Missouri and illustrates a region in southwest Missouri. Springfield is the largest southwest Missouri city. South-oriented streams flowing to the figure 1 south edge flow to the southeast-oriented White River which eventually reaches the south-oriented Mississippi River. The Osage River is near the figure 1 north edge and is formed near Schell City (near the west edge) at the confluence of tributaries from west of the figure 1 and flows in an east and northeast direction to Harry S. Truman Reservoir. From Harry S. Truman Reservoir the Osage River flows in an east direction to the Lake of the Ozarks (another large reservoir flooding the Osage River valley) and finally turns to flow in a northeast direction to the figure 1 north edge. North of the figure 1 map area the Osage River joins the Missouri River which then flows in an east direction to join the south-oriented Mississippi River valley. Important to this essay are two north-oriented Osage tributaries joining the Osage River south of Harry S. Truman Reservoir. The first is the Pomme de Terre River which originates north and east of Springfield and which flows in a north-northwest direction to Pomme de Terre Lake (another reservoir) and then in a north direction to join the Osage River at Harry S. Truman Reservoir. The second Osage River tributary is the Sac River, which originates west of Springfield and which flows in a north-northwest and north-northeast direction to join the Osage River near Osceola. The Little Sac River is a north-northwest oriented tributary originating north of Springfield and joining the Sac River in a reservoir located south of Stockton. Weaubleau Creek is the unlabeled north-northwest tributary located between the Sac River and Pomme de Terre River originating just west of Pomme de Terre Lake and joining the Osage River a short distance downstream from Osceola. the Weaubleau Creek-Little Sac River drainage divide area in St Clair, Hickory, Cedar, and Polk Counties essay addressed the region located west and south of the Osage River-Weaubleau Creek drainage divide area discussed here and can be found under Osage River on the sidebar category list. These drainage divide areas are among several hundred Missouri River drainage basin drainage divides illustrated and discussed on this Missouri River drainage basin landform origins research project website. Project essays present evidence for immense south-oriented floods from a rapidly melting North American ice sheet. Prior to headward erosion of the deep east-oriented Osage River valley south-oriented flood waters flowed across the figure 1 map area to what were then actively eroding south-oriented valleys, which had eroded headward from what was then the newly eroded southeast-oriented White River valley. Headward erosion of the deep east-oriented Osage River valley beheaded the south-oriented flood flow routes in sequence and triggered a massive flood flow reversal. The flood flow reversal was responsible for eroding the north-oriented Osage River tributary valleys and for creating the Osage River-White River drainage divide.

Osage River-Weaubleau Creek drainage divide area detailed location map

Figure 2: Osage River-Weaubleau 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 Osage River-Weaubleau Creek drainage divide area in St Clair, Benton, and Hickory Counties, Missouri. County names and boundaries are shown as are all of St Clair and Hickory Counties and relevant areas of Benton County. The Osage River flows from the figure 2 west edge in an east direction across central St Clair County to Osceola and then in a north direction to the St Clair-Henry County border. From the St Clair-Henry County border the Osage River flows in an east and north direction to the dam responsible for impounding the Harry S. Truman Reservoir. Downstream from the dam the Osage River flows to Warsaw and then in an east direction to the figure 2 east edge. Throughout its length, and especially in the Harry S. Truman Reservoir region, the Osage River has eroded some spectacular incised meanders. The Pomme de Terre River is the north-oriented river flowing through Hickory County to join the Osage River south of the Harry S. Truman Reservoir dam. Hermitage is the Hickory County town located on the Pomme de Terre River north of the dam creating Pomme dr Terre Lake. The Sac River is the north-oriented tributary joining the Osage River a short distance south (or upstream) of Osceola in St Clair County. Weaubleau Creek originates near Rondo (near the figure 2 south edge south of Hickory County and between the railroad line and the Pomme de Terre River) and flows in a north-northwest direction to join the Osage River a short distance downstream from Osceola. Bear Creek is a north-northwest oriented Osage River tributary located east of Weaubleau Creek and Hogles Creek is a north-northwest, north, and northeast oriented Osage River tributary located east of Bear Creek and west of the Pomme de Terre River. The unlabeled north-oriented Pomme de Terre River tributary east of Hogles Creek is the Little Pomme de Terre River. All major drainage routes in the Osage River-Weaubleau Creek drainage divide in St Clair, Benton, and Hickory Counties are north-oriented and were eroded during a massive reversal of south-oriented flood flow triggered by headward erosion of the deep east-oriented Osage River valley. Prior to headward erosion of the Osage River valley flood waters were flowing south across the figure 2 map area from a rapidly melting North American ice sheet in the north to actively eroding south-oriented White River tributary valleys. Headward erosion of the deep Osage River valley beheaded south-oriented flood flow routes in sequence from east to west. Flood waters on north ends of newly beheaded flood flow routes reversed flow direction to flow north to the newly eroded and deep Osage River valley and began to erode deep north-oriented Osage River tributary valleys. Because flood flow was beheaded in sequence from east to west and because flood flow routes were interconnected reversed flood flow east of the actively eroding Osage River valley head was flowing north while flood flow west of the actively eroding Osage River valley head was flowing south. The north-oriented reversed flood flow routes were able to capture flood flow from the yet to be beheaded flood flow routes further to the west and such captures of continuing south-oriented flood flow provided the water volumes required to erode significant and deep north-oriented Osage River tributary valleys.

Osage River-Pomme de Terre River drainage divide area

Figure 3: Osage River-Pomme de Terre River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 3 illustrates the Osage River-Pomme de Terre River drainage divide area north of where northwest-oriented Weaubleau Creek joins the Osage River (located south of the figure 3 southwest corner). The Osage River flows around Horseshoe Bend in the figure 3 southwest corner and then flows north into the figure 3 north half. The Osage River valley in figure 3 is flooded by Harry S. Truman Reservoir. Once in the figure 3 north half the Osage River flows around Talley Bend, Harris Bend, Smith Bend, and Berry Bend in some rather spectacular incised meanders before joining the north oriented Pomme de Terre River in the figure 3 northeast quadrant and then flowing north to the figure 3 north edge. North of figure 3 the Osage River flows around Shawnee Bend before flowing in a southeast direction to Harry S. Truman Dam, which is a short distance north of the figure 3 northeast corner. The Pomme de Terre River flows in a north-northwest direction to join the Osage River in the figure 3 northeast quadrant. Little Pomme de Terre River is the north-oriented stream located west of the Pomme de Terre River and joining the Pomme de Terre River in the figure 3 east center area. Hogles Creek is the north-, east, and north oriented tributary flowing through the figure 3 south center area and joining the Osage River near its junction with the Pomme de Terre River. Little Hogles Creek is the north-oriented Hogles Creek tributary located between Hogles Creek and the Little Pomme de Terre River. The northwest-oriented Osage River tributary in the figure 3 southwest quadrant is Wright Creek. All major Osage River tributaries valleys in the figure 3 map area are north oriented and were eroded during a massive reversal of an immense south-oriented flood. South-oriented flood waters initially flowed across a topographic surface at least as high as the highest figure 3 elevations today and at that time none of the deep valleys existed. The deep Osage River valley head probably made use of south-oriented flood flow channels as it eroded headward (or west). The Osage River valley beheaded the south-oriented flood flow channels one channel at a time from east to west. Flood waters on north ends of newly beheaded flood flow channels reversed flow direction to flow north into the newly eroded and deep Osage River valley. The north-oriented reversed flow captured south-oriented flood flow from channels west of the actively eroding Osage River valley. In other words a north-oriented valley was eroded south by north-oriented flood flow and captured south-oriented flood flow from a channel further to the west. The captured flood water then eroded an east-oriented valley to the south-oriented flood flow channel and then eroded a deep valley northward in the south-oriented flood flow channel. The deep south-oriented valley then captured south-oriented flood flow from a flood flow channel still further to the west and a deep east-oriented valley then beheaded south-oriented flood flow in that further west channel. In this manner the Osage River valley incised meanders were eroded.

Detailed map of Osage River-Hogles Creek drainage divide area

Figure 4: Detailed map of Osage River-H0gles Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 4 provides a detailed map of the Osage River-Hogles Creek drainage divide area seen in less detail in figure 3 above. The Osage River flows north along the figure 4 west edge and north of the figure 4 map area flows around Smith Bend and then flows south into the figure 4 map area before turning to flow east around Berry Bend and then flowing north to the figure 4 north center edge. Hogles Creek flows north from the figure 4 south edge (just east of the St Clair-Benton County line) and as it approaches the Osage River incised meander Hogles Creek turns to flow in a southeast direction and then turns to flow north before turning to flow in southeast direction to the figure 4 east edge. The north-northwest oriented stream tributary flowing from the figure 4 southeast corner to join the southeast-oriented Hogles Creek segment is Little Gales Creek. Note the drainage divide near the figure 4 center between the north-oriented Osage River valley east of Berry Bend and the north-oriented Hogles Creek valley near the north-south oriented county line. A through valley has been eroded across the narrow Osage River-Hogles Creek drainage divide and has two parallel channels. Floors of those through valley channels have an elevation of between 840 and 850 feet. The hill to the southwest rises to at least 940 feet and a hill to the northeast rises to at least 930 feet. The through valley provides evidence of a south-oriented flood flow route that existed prior to being beheaded by headward erosion of the deep Osage River valley. Higher level north-south oriented through valleys can be seen near the road junction southwest of the hill which rises to more than 940 feet. These through valleys link an east-oriented Hogles Creek tributary with two northwest-oriented tributaries to the north-oriented tributary joining the south-oriented Osage River valley near the figure 4 north edge (west half). These two through valleys provide evidence of additional south-oriented flood flow channels, which were captured by headward erosion of the deep Hogles Creek valley from the newly eroded Osage River valley. Study of the figure 4 map area suggests south-oriented flood water initially flowed on a topographic surface at least as high as the highest figure 4 elevations today and the deep north-south valley orientations probably evolved from the earlier south-oriented anastomosing flood flow channel orientations as the deep east-oriented Osage River valley and tributary valleys eroded headward into the region and triggered a massive flood flow reversal to erode north-oriented valleys.

Little Pomme de Terre River-Pomme de Terre River drainage divide area

Figure 5: Little Pomme de Terre River-Pomme de Terre River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 5 illustrates the Little Pomme de Terre River-Pomme de Terre River drainage divide south of the figure 3 map area and includes an overlap strip with figure 3. Quincy is the small town located on the north-south oriented highway just south of the figure 5 center area. The Pomme de Terre River makes some spectacular incised east-west oriented meanders as it flows north along the south half of the figure 5 east edge and then flows north, west, and north to the figure 5 north edge (east half). The Little Pomme de Terre River is the north, northwest, and north oriented stream located east of the north-south highway and flowing from the figure 5 south edge to join the Pomme de Terre River just north of the figure 5 north edge. Jennings Hollow, Trinity Hollow, and Montgomery Hollow are northwest-oriented valleys draining to the north-oriented Little Pomme de Terre River. Hogles Creek is the north-oriented stream west of the north-south highway flowing from the figure 5 south edge to the figure 5 north edge. The flooded Osage River valley at the southeast end of Horseshoe Bend can  just barely be seen in the figure 5 northwest corner. Bear Creek is the north-northwest and northwest oriented stream flowing from the figure 5 south edge (by the St Clair County-Hickory County line) to the figure 5 west edge (north half). West of figure 5 Bear Creek joins the north-oriented Osage River on the east side of Horseshoe Bend (see figure 2). South, southwest, and west oriented Clear Creek in the figure 5 southwest corner area flows to north-oriented Weaubleau Creek located just west of the figure 5 map area. Note how with few exceptions the figure 5 drainage routes are north oriented and are located in relatively narrow north-oriented drainage basins. These narrow north-oriented drainage basins originated as south-oriented flood flow channels on a topographic surface at least as high as the highest figure 5 elevations today. The south-oriented flood flow channels were beheaded in sequence from east to west by headward erosion of the deep Osage River valley north of the figure 5 map area. Flood waters on north ends of the beheaded flood flow routes reversed flow direction to erode deep north-oriented Osage River tributary valleys and to capture south-oriented flood flow from flood flow channels still west of the actively eroding Osage River valley head. Captured flood flow moved east into the newly reversed and rapidly eroding north-oriented Osage River tributary valleys. Shallow through valley eroded across the Little Pomme de Terre River-Pomme de Terre River drainage divide in the figure 5 east half provide evidence of this east-oriented flood flow movement.

Detailed map of Trinity Hollow-Mining Hollow drainage divide area

Figure 6 provides a detailed map of the Trinity Hollow-Mining Hollow drainage divide area seen in less detail in figure 5 above. White Cloud is the small community located near the figure 6 south center area. Incised meanders of the north-oriented Pomme de Terre River can be seen along the figure 6 east edge. Mining Hollow is the northeast and east oriented valley in sections 21, 16, and 15 draining to the Pomme de Terre River. Sloan Hollow is the southeast, northeast, and east oriented valley in sections 28 and 27 draining to the Pomme de Terre River. Trinity Hollow is the northwest-oriented valley extending from south of White Cloud to the figure 6 northwest corner. Montgomery Hollow is the northwest-oriented valley in the figure 6 southwest quadrant. Trinity Hollow and Montgomery Hollow drain to the north-oriented Little Pomme de Terre River located west of the figure 6 map area. Note the shallow west to east oriented through valley in section 20 linking northwest-oriented Trinity Hollow with east, northeast, and east oriented Mining Hollow. Also note in section 29 a shallow through valley linking the northwest-oriented Trinity Hollow valley with the southeast, northeast, and east oriented Sloan Hollow valley. These through valleys, while subtle features and easy to miss, provide evidence of flood flow routes that moved south oriented flood flow from the Little Pomme de Terre River alignment (which at that time was west of the actively eroding Osage River valley head location) to the newly reversed flood flow on the Pomme de Terre River alignment (which had just been beheaded and reversed by headward erosion of the deep east-oriented Osage River valley head). Note further how the flood flow routes defined by the Mining Hollow and Sloan Hollow valley orientations today are related to the Pomme de Terre River incised meander orientations. While I can not say for sure, I suspect the incised meanders resulted from headward erosion of the north-oriented Pomme de Terre River valley across northeast oriented flood flow channels eroded by south oriented flood flow from west of the Osage River valley head being captured by newly reversed and north-oriented flood flow routes east of the actively eroding Osage River valley head. The captured flood flow often moved in a southeast and then northeast direction and those directions are reflected in orientations of the figure 6 valleys (except the southeast-oriented flow routes have since been reversed to become northwest-oriented valleys and east of the Pomme de Terre River valley the northeast and north-oriented flow routes are now south and southeast-oriented valleys).

Weaubleau Creek-Pomme de Terre drainage divide area

Figure 7: Weaubleau Creek-Pomme de Terre drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 7 illustrates the Weaubleau Creek-Pomme de Terre River drainage divide area south of the figure 5 map area and includes an overlap area with figure 5. White Cloud is the small town located near the north edge in the figure 7 northeast quadrant. Weaubleau is the larger town located in the figure 7 southwest quadrant and Wheatland is the larger town located just east of the Wheatland Prairie area. Quincy is the small town located in the figure 7 north center area. The meandering Pomme de Terre River is located along the figure 7 east edge. Pomme de Terre Lake in the figure 7 southeast corner is a reservoir flooding the Pomme de Terre River valley. Weaubleau Creek flows north from the figure 7 south edge just east of Weaubleau and Little Weaubleau Creek is the Weaubleau Creek tributary draining the figure 7 center area and flowing in a west-northwest direction to join Weaubleau Creek north of the town of Weaubleau. West of the figure 7 map area Weaubleau Creek turns to flow in a north direction to join the Osage River. The Little Pomme de Terre River flows in a northwest direction from near Wheatland toward Quincy and then turns to flow in a north direction to the figure 7 north edge. West of Quincy is north-oriented Hogles Creek which originates as west- and northwest-oriented streams in the Wheatland Prairie region west of Wheatland. Northwest-oriented Montgomery Hollow is located between the north-oriented Little Pomme de Terre River and town of White Cloud near the figure 7 north edge. Note how north of Wheatland shallow through valleys link the northwest-oriented Little Pomme de Terre River and Montgomery Hollow headwaters valleys with tributary valleys to the north-oriented Pomme de Terre River. These through valleys while shallow (they are defined by a single ten-meter contour line on each side) provide evidence of flood flow routes used by captured flood water which had been moving south on the Little Pomme de Terre River alignment which was moving to newly beheaded and reversed north-oriented flood flow on the Pomme de Terre River alignment. Headward erosion of the deep Osage River valley north of the figure 7 map area subsequently beheaded and reversed flood flow on the Little Pomme de Terre River alignment which resulted in erosion of the north-oriented Little Pomme de Terre River valley. The figure 7 map does not show enough detail to show through valleys between west-oriented Little Weaubleau Creek tributary valleys and the north-oriented Pomme de Terre River valley, although on more detailed maps such through valleys are seen and defined by one or two 10-foot contour lines on each side.

Detailed map of Little Pomme de Terre River-Vanderman Branch drainage divide area

Figure 8 provides a detailed map of the Little Pomme de Terre River-Vanderman Hollow drainage divide area located north of Wheatland, Missouri. Wheatland is the town located in the figure 8 southwest corner. The Little Pomme de River flows in a northwest direction north of Wheatland to the figure 8 west edge. Note northwest and west oriented Little Pomme de Terre River tributary valleys. North-oriented drainage in sections 7 and 8 near the figure 8 north edge flows to northwest-oriented Montgomery Hollow, which north and west of the figure 8 map area joins the north-oriented Little Pomme de Terre River. The north-oriented Pomme de Terre River meanders along and across the figure 8 east edge. Vanderman Branch is the northeast, east-southeast, and north-northeast oriented stream flowing across the figure 8 center area to join the Pomme de Terre River near the figure 8 east edge. Jordan Branch is the northeast and north-northwest oriented Vanderman Branch tributary located in the figure 8 south center area. Note how west and northwest-oriented Little Pomme de Terre River and Montgomery Hollow tributary valleys are linked by shallow through valleys eroded across the drainage divide with the Vanderman Branch valley. The through valleys provide evidence water once flowed across what is now the Little Pomme de Terre River-Pomme de Terre River drainage divide. My interpretation is the water had been flowing south on the Little Pomme de Terre River alignment and had been first captured by reversed flood flow on beheaded flood flow routes east of the figure 8 map area. This flood water was moving southeast and then northeast to those new and rapidly eroding deep north-oriented Osage River tributary valleys. Headward erosion of the deep north-oriented Pomme de Terre River valley then captured the southeast and northeast oriented flood flow and the captured flood water then moved “straight” north in the newly eroded Pomme de Terre River valley. The deep Pomme de Terre River valley as it eroded headward (or south) made use of segments of the northeast and southeast oriented flood flow channels it crossed. Use of those previously eroded flood flow channels (the floors of which were probably at the level of the present day Little Pomme de Terre River-Pomme de Terre River valley divide) probably contributed to the development of the incised meanders seen along the north-oriented Pomme de Terre River valley today.

Weaubleau Creek-Pomme de Terre Lake drainage divide area

Figure 9: Weaubleau Creek-Pomme de Terre Lake drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 9 illustrates the Weaubleau Creek-Pomme de Terre Lake drainage divide area located south of the figure 7 map area and includes overlap areas with figure 7. Hermitage is the town located near the figure 9 northeast corner. Wheatland is the town located just east of the figure 9 east center edge. Weaubleau is the town located near the figure 9 west edge. Pomme de Terre Lake is located in the figure 9 east half and floods the valley of the north, northeast, and north oriented Pomme de River. The dam impounding Pomme de Terre Lake is located in the figure 9 northeast quadrant. The meandering north and northwest oriented stream with a flooded valley near the figure 9 west center edge is Lindley Creek. Weaubleau Creek flows north, northwest, north, and northwest from the figure 9 south center edge area to the figure 9 northwest corner. Little Weaubleau Creek is the west-northwest oriented Weaubleau Creek tributary located east of the town Weaubleau. West and northwest oriented streams west of Wheatland in the figure 9 north center area flow to north oriented Hogles Creek. Study of the figure 9 drainage divide between the northwest- and west-oriented Weaubleau Creek tributary valleys and the north-oriented Pomme de Terre River valley suggests any through valleys eroded across the drainage divide are shallow. Orientation of drainage routes on either side of the divide however does suggest prior to the reversal of flood flow in the Hogles Creek and Weaubleau Creek valleys flood waters flowed in a southeast direction to cross what are now the Hogles Creek-Pomme de Terre River and Weaubleau Creek-Pomme de Terre River drainage divides. Orientations east of the drainage divide suggest once across the drainage divide the flood waters turned to flow in a northeast direction to what was then the rapidly eroding and deep north-oriented Pomme de Terre River valley. Headward erosion of the deep Osage River valley north of the figure 9 map area subsequently beheaded south-oriented flood flow routes on the Hogles Creek and Weaubleau Creek alignments causing a massive flood flow reversal that eroded the north-oriented Hogles Creek and Weaubleau Creek valley systems.

Detailed map of Weaubleau Creek-Pomme de Terre River drainage divide area

Figure 10: Detailed map of Weaubleau Creek-Pomme de Terre River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 10 provides a detailed map of a Weaubleau Creek-Pomme de Terre River drainage divide area located south of the figure 9 map area. The meandering north-northeast oriented river in the figure 10 east half is the Pomme de Terre River and the flooded valley along the north half of the figure 10 east edge is the south end of Pomme de Terre Lake. Weaubleau Creek flows in the figure 10 west half. Note how the west-oriented Weaubleau Creek tributary in sections 14 and 15 is linked by a through valley in section 14 with an east-southeast oriented Pomme de Terre River tributary valley. This is one of the deepest through valleys eroded across the Weaubleau Creek-Pomme de Terre River drainage divide. The through valley floor elevation at the drainage divide is between 1030 and 1040 feet. To the north the highest figure 10 drainage divide elevation is between 1070 and 1080 feet, however just north of the figure 10 map area drainage divide elevations rise to more than 1140 feet. The highest figure 10 drainage divide near Rondo near the figure 10 south edge is greater than 1090 feet, however proceeding a short distance south of the figure 10 map area there are drainage elevations higher than 1140 feet. In other words, what looks like a relatively shallow and narrow through valley is in fact a deep channel eroded into the floor of a much broader and deeper west to east oriented through valley that records the erosion of at least 100 feet or more of material from the much of the figure 10 Weaubleau Creek-Pomme de Terre River drainage divide area. The depth and width of the eroded region provides some clues as to magnitude of the flood flow involved and also provides some clues as to what was happening further to the north. What looked like shallow valleys eroded across present day drainage divides were in fact channels on the floors of much broader and deeper through valleys where flood erosion removed evidence of the valley walls. Volumes of flood water involved were immense and for at least a brief period of time flood waters were flowing south in the figure 10 west half and were being captured by north-oriented flood flow in the figure 10 east half. And as the captured flood waters flowed across the present day Weaubleau Creek-Pomme de Terre River drainage divide flood water erosion lowered the drainage divide area by 100 feet or more while eroding an even deeper north-oriented Pomme de Terre River valley (and a deep north-oriented Weaubleau Creek valley when all south-oriented flood flow was reversed).

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 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.