Abstract:

Topographic map evidence is used to interpret landform origins in drainage divide areas between Chariton River tributaries and between the Chariton River and Mississippi River tributaries located in Appanoose County, Iowa. The Chariton River flows in a southeast and south-southeast direction across Appanoose County and south of Appanoose County flows in a south direction to join the Missouri River. Several major east and northeast oriented tributaries join the Chariton River in Appanoose County and one major east and southeast oriented Chariton River tributary flows through Appanoose County. Tributaries to these major Chariton River tributaries suggest the presence of multiple former southeast or south-southeast oriented flood flow channels across the Appanoose County region. In addition to valley orientations shallow through valleys can be found crossing some drainage divides and further support this flood origin interpretation. Flood water are interpreted to have been derived from a rapidly melting North American ice sheet located north of Appanoose County. North of the southeast-oriented Chariton River are east and northeast oriented Des Moines River tributaries, with the Des Moines River flowing in a southeast direction to the Mississippi River. East of the south-southeast oriented Chariton River in Appanoose County are headwaters of three different southeast-oriented Mississippi River tributaries. The multiple closely spaced and parallel Mississippi River tributary valleys suggests the presence of a former southeast-oriented anastomosing channel complex which was partially beheaded and captured by headward erosion of the deep south-oriented Chariton River valley. Headward erosion of east and northeast oriented Des Moines River tributary valleys beheaded flood flow routes to the newly eroded south-oriented Chariton River valley.

Preface:

Introduction:

• The purpose of this essay is to use topographic map interpretation methods to explore the Chariton River and tributary drainage divide area landform origins in Appanoose County, Iowa, 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 essay 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 essays in the Missouri River drainage basin landform origins research project is a thick North American ice sheet, comparable in thickness to the Antarctic ice sheet, occupied the North American region usually recognized to have been glaciated, and through its weight and erosive actions created a deep North American “hole”. The southwestern rim of that deep “hole” is today preserved in the high Rocky Mountains. The ice sheet through its weight and deep erosion (and perhaps deposition along major south-oriented melt water flow routes) caused significant crustal warping and tectonic change, through its action of melting fast produced immense floods that flowed across the continent, and through its action of melting fast systematically opened up space in the ice sheet created “hole” so headward erosion of newly developed north-oriented drainage systems captured immense south-oriented melt water floods and diverted immense melt water floods north into space the ice sheet had once occupied.
• If this previously unexplored paradigm is correct the geographic region explored by this essay should contain evidence of immense floods that were captured by headward erosion of new valley systems so as to cause the floods to flow in a different direction. Ability of this previously unexplored paradigm to explain Chariton River and tributary drainage divide area landform evidence in Appanoose County, Iowa will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm (see menu at top of page for a paradigm related essay). This essay is included in the Missouri River drainage basin landform origins research project essay collection.

Chariton River and Appanoose County, Iowa location map

Figure 1: Chariton River and Appanoose County, Iowa 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 Chariton River and Appanoose County, Iowa location map. The state of Iowa is labeled and occupies much of the figure 1 map area. Missouri is the state located south of Iowa. The south-oriented Mississippi River is located along the Iowa and Missouri eastern borders and eventually flows to the Gulf of Mexico. Note the numerous southeast oriented Mississippi River tributaries located in Iowa and in northeast Missouri. The Des Moines River is a major southeast oriented Mississippi River and flows in a south-southeast direction from the figure 1 north edge to Des Moines, Iowa and then in a southeast direction to the Iowa-Missouri border where it joins the Mississippi River. Note southeast, east, and northeast oriented Des Moines River tributaries west and south of Des Moines. The Missouri River is located along the Iowa and Missouri western borders (as seen in the figure 1 southwest quadrant) and south of the figure 1 map area flows in more of an east direction to join the south-oriented Mississippi River. Note south-southwest and south oriented Missouri River tributaries in western Iowa and flowing from Iowa across northern Missouri to the Missouri River (located south of the figure 1 map area). The Chariton River originates in southern Iowa, south of Des Moines, and flows in an east direction to Rathbun Lake before gradually turning to flow in a south direction to the figure 1 south edge and the Missouri River. North and east of the Chariton River in Iowa are east and northeast-oriented Des Moines River tributaries so the drainage divide between the (upper) Mississippi River drainage basin and the Missouri River drainage basin is located just north and east of the east, southeast, and south-oriented Chariton River in Iowa. The Appanoose County Iowa area includes the Chariton River segment from Rathbun Lake to the Iowa-Missouri state line and includes the towns of Mystic, Centerville, and Moulton (Seymour is located just west of the Appanoose County western border). This essay focuses on drainage divides between Chariton River tributaries in Appanoose County and also on drainage divides between the Chariton River and an east-oriented Des Moines River tributary (South Soap Creek) and between the Chariton River and three southeast-oriented Mississippi River tributaries (the Fox, Wyaconda, and North Fabius Rivers). The Des Moines River-Missouri River drainage divide area landform origins in Clarke, Lucas, and Monroe Counties, Iowa essay addressed the region north of the east-oriented Chariton River segment. Drainage divide origins in the area directly west of Appanoose County are addressed in the Chariton River-Grand River drainage divide area in Lucas, Decatur, and Wayne Counties essay. These and other regional drainage divide area essays can be found listed under Iowa or Chariton River on the sidebar category list.

• The Appanoose County, Iowa area and for that matter the entire figure 1 map area was eroded by massive south-oriented melt water floods as the present day drainage system evolved. Flood waters were derived from a rapidly melting thick North American ice sheet, the southern margin of which at the time figure 1 drainage systems evolved was located north of the figure 1 map area. The ice sheet had been comparable in size, if not larger, than the modern Antarctic Ice Sheet and had been located in a deep “hole.” The deep “hole” had been formed by a combination of crustal warping and of deep glacial erosion and the figure 1 map area would have been located along the deep “hole’s” southern rim. Prior to formation of present day figure 1 drainage systems immense south-oriented melt water floods overwhelmed whatever drainage networks existed and flowed across the entire figure 1 map region in a south direction towards the Gulf of Mexico and deeply eroded the deep “hole’s” southern rim. How much bedrock material flood waters stripped from the figure 1 map area may never be determined, although it could measure in the hundreds of meters. The south-oriented Mississippi River valley, which may not have been initiated prior to the ice sheet’s formation, was eroded headward from the Gulf of Mexico as it captured the immense south-oriented floods by eroding tributary valleys headward both to the east and west. These tributary valleys eroded headward in sequence from south to north. South of the figure 1 map area in the state of Arkansas the southeast-oriented Arkansas River valley eroded headward to capture flood flow in advance of White River valley headward erosion, which beheaded flood flow routes to the newly eroded Arkansas River valley and its tributary valleys. Next headward erosion of the Missouri River valley and its east and northeast oriented tributary valleys across the state of Missouri beheaded south-oriented flood flow routes to the newly eroded White River valley and its tributary valleys. South-oriented tributary valleys then eroded headward along south-oriented flood flow routes from the actively eroding Missouri River valley into the figure 1 map area while at the same time headward erosion of additional southeast-oriented Mississippi River tributary valleys, including the Des Moines River valley and its tributary valleys, was beheading south-oriented flood flow routes to the actively eroding south-oriented Missouri River tributary valleys. The east oriented Chariton River headwaters segment was probably initiated by headward erosion of deep southeast-oriented anastomosing channel complex from the Mississippi River valley and beheaded south-oriented flood flow to actively eroding south-oriented Missouri River tributary valleys, although headward erosion of the south-oriented Chariton River valley captured some developing east- and southeast-oriented flood flow routes and diverted the flood water to the newly eroded Missouri River valley.

Detailed Chariton River and Appanoose County location map

Figure 2: Detailed Chariton River and Appanoose County location map.United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

 

• Figure 2 provides a somewhat more detailed map of the Chariton River and Appanoose County, Iowa area. County names and boundaries are shown with Appanoose County, Iowa being located in the figure 2 southeast quadrant. The west to east oriented Iowa-Missouri state line is located directly south of Appanoose County and Putnam and Schuyler Counties are located in Missouri. The Chariton River originates as Chariton Creek near Weldon (located on the Clarke-Decatur County border) and flows in an east-northeast, east, and northeast direction to Chariton in Lucas County. At Chariton the Chariton River turns to flow in a southeast direction to the Appanoose County northwest corner and enters Rathbun Lake, a large reservoir flooding the Chariton River valley. From Rathbun Lake the Chariton River flows in a south-southeast direction to the Missouri state line and then in a south direction along the Putnam-Schuyler County line. Major east and northeast-oriented Chariton River tributaries shown in Appanoose County are from the west and (from north to south) are the South Fork Chariton River, Walnut Creek, Cooper Creek, and Shoal Creek, which turns to flow in a south-southeast direction into Putnam County before flowing to the Chariton River. No significant Chariton  River tributaries are shown in the Appanoose County area from the north and east. The southeast oriented Des Moines River flows through Ottumwa in Wapello County and drainage routes shown in figure 2 north of the Chariton River eventually drain to the Des Moines River. North-northwest oriented Mormon Branch and Ingraham Branch in southern Monroe County flow to the east-northeast, northwest, and northeast oriented Cedar Creek which joins the Des Moines River near the Marion-Mahaska County border. East of the Chariton River in the Appanoose County northeast corner is southeast- and east-oriented South Soap Creek, which flows to east-northeast oriented Soap Creek, which joins the southeast-oriented Des Moines River near the Wapello County southeast corner. Between Udel and Moulton in eastern Appanoose County are east-oriented headwaters of southeast-oriented Fox River, which flows directly to the Mississippi River, adjacent to and parallel to the Des Moine River. In the Appanoose County southeast corner, south and east of Moulton, are headwaters of southeast-oriented North Fabius River, which with the Fabius River represents another of the closely spaced elongate and parallel southeast-oriented Mississippi River tributaries. Between the Fox River and North Fabius River headwaters are headwaters of the southeast-oriented South Wyaconda River. The Appanoose County region is then located along a major divide between southeast-oriented Mississippi River tributary drainage basins to the north and east and the Missouri River drainage basin to the south and west. Note how with the exception of the east- and southeast-oriented Chariton River almost all Missouri River tributaries shown in figure 2 are oriented in south directions while almost all Mississippi River tributaries are oriented in southeast directions, although several of the southeast-oriented Mississippi River tributaries have east, east-northeast, and northeast oriented tributaries and/or headwaters.

South Soap Creek-Chariton River drainage divide area

Figure 3: South Soap Creek-Chariton River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

• Figure 3 illustrates the South Soap Creek-Chariton River drainage divide area north and east of Centerville, Iowa. Centerville is the large town located in the figure 3 southwest quadrant. The southeast end of Rathbun Lake and Rathbun Dam are located in the northwest quadrant and the Chariton River flows in a south-southeast direction from Rathbun Dam to the figure 3 south center edge. Udell is the much smaller town located east and south of the figure 3 center. The reservoir located north of Udell is located on southeast and east oriented South Soap Creek, which flows to the figure 3 east edge (just south of northeast corner) and then to Soap Creek, which flows to the Des Moines River. Note the north-oriented tributary originating near Udell and flowing to the reservoir in the South Soap Creek valley. The north oriented tributary valley is linked by a shallow through valley with a southwest and south oriented Chariton River tributary. The through valley provides evidence of a south-oriented flood flow route to what was then the actively eroding Chariton River valley (and Missouri River valley) prior to headward erosion of the deep South Soap Creek valley. Headward erosion of the South Soap Creek valley (from the actively eroding Soap Creek valley and Des Moines River valley) beheaded the flood flow route and diverted the south-oriented flood flow from the developing Missouri River drainage system to the developing Des Moines River drainage system. Flood waters on the north end of the beheaded flood flow route eroded the north-oriented tributary valley. Just east of the north-oriented South Soap Creek tributary valley, on the upland at the edge of the east oriented South Soap Creek valley, are northeast-oriented headwaters of east-southeast oriented North Fox Creek, which flows to the southeast-oriented Fox River, which flows directly to the Mississippi River. The east-oriented stream flowing to the figure 3 east edge south of North Fox Creek are Fox River tributaries. Note how the South Soap Creek valley floor is approximately 20 meters deeper than the erosion (deposition?) surface on which the adjacent North Fox Creek headwaters originate. This evidence suggests headward erosion of the deep South Soap Creek valley beheaded flood flow routes to the actively eroding Fox Creek valley, which the west end of which had previously been captured by headward erosion of the deep south-oriented Chariton River valley. The lack of any significant east-oriented Chariton River tributary valleys in the figure 3 map area provides further evidence supporting this flood capture interpretation. In summary, the figure 3 map evidence suggests south-oriented flood flow moving across the figure 3 map area was first captured by headward erosion of east-oriented tributary valleys from the southeast-oriented Fox River valley, which had eroded headward from the Mississippi River valley. Second, headward erosion of the deeper Chariton River valley from the Missouri River valley captured the west ends of the developing east-oriented Fox River tributary valleys. Finally headward erosion of the deep South Soap Creek valley from the Des Moines River valley captured a developing south-oriented flood flow route just west of Udell to the south-oriented Chariton River valley.

Detailed map of South Soap Creek-Chariton River drainage divide area

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

 

• Figure 4 provides a detailed topographic map of the South Soap Creek-Chariton River drainage divide area located north and west of Udell (seen in less detail in figure 3 above). Udell is the town located in the figure 4 southeast corner. The southeast-oriented Chariton River valley is located in the figure 4 southwest corner. The east-oriented South Soap Creek valley is located in the figure 4 northeast corner. Hiattsville is the very small town located in the figure 4 northwest quadrant (at corner of sections 27, 28, 33, and 34). East-oriented drainage in the figure 4 southeast corner (just east of Udell) flows to the southeast-oriented Fox River and the northeast and east-southeast oriented Fox Creek headwaters are located just east of the figure 4 northeast quadrant. The south-oriented drainage system in the figure 4 southeast quadrant (just west of Udell) flows to the south-oriented Chariton River. Note the shallow through valley linking that south-oriented Chariton River tributary valley with the north-oriented South Soap Creek tributary valley directly to the north. The map contour interval is 10 feet and the through valley is defined by two contour lines on each side. While the through valley looks small and insignificant it does provide evidence of south-oriented flood flow to the Chariton River valley prior to headward erosion of the deep South Soap Creek valley. Note how the north-oriented South Soap Creek tributary valley has northeast, east, and southeast oriented tributary valleys. Those northeast, east, and southeast oriented tributary valleys were eroded by flood flow from west of the actively eroding South Soap Creek valley head which was captured by reversed flood flow on the north end of the beheaded south-oriented flood flow route. The south-oriented Chariton River tributary valleys south of Hiattsville eroded headward to capture some of that southeast-oriented flood flow while southwest-oriented Chariton River tributary valleys west of Hiattsville captured still more of the southeast-oriented flood flow. At the same time the South Soap Creek valley was eroding headward in a northwest direction to capture additional southeast-oriented flood flow. The through valley is shallow which suggests flood waters were flowing across the entire region on the erosion (deposition?) surface located between the present day valleys. At that time flood waters had not eroded deep channels into that erosion (deposition?) surface and instead were flowing as large sheets of water, probably extending across the entire region.

Chariton River=South Fork Chariton River drainage divide area

Figure 5: Chariton River-South Fork Chariton River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

• Figure 5 illustrates the Chariton River-South Fork Chariton River drainage divide area in northwest Appanoose County. The Chariton River is located in the figure 5 north center edge area where it flows into the southeast-oriented Rathbun Lake. Lost Branch is the northeast oriented Chariton River tributary located in the figure 5 northwest corner. Goodwater Creek is the northeast- and north-oriented Chariton River tributary west of the figure 5 north center area. Note how both Lost Branch and Goodwater Creek have north-oriented tributaries and how there are unnamed north-oriented Chariton River tributaries located downstream from Goodwater Creek. The South Fork Chariton River flows in an east direction from the figure 5 west edge (south half) and makes a jog in a southeast direction in the figure 5 south center area before flowing in a northeast direction to Rathbun Lake. Note the north-oriented tributaries flowing to the South Fork Chariton River. The southeast-oriented tributary flowing from the figure 5 west center edge to the South Fork in the figure 5 southwest quadrant is Jordan Creek. The east and south-southeast oriented tributary flowing across the figure 5 center area (south of the town of Confidence) is Walker Branch. Catfish Branch is the labeled south-southeast oriented South Fork tributary east of Walker Branch. Note other unlabeled southeast and south-southeast oriented South Fork tributaries. The figure 5 map contour interval is 20 meters and relief on the upland surface is low making it impossible to identify shallow through valleys. However, based on valley orientations the following figure 5 map area drainage history is offered. Initially south and/or southeast oriented flood flow moved across the figure 5 map area on an erosion (deposition?) surface at least as high as the present day upland surface. Headward erosion of the deep northeast-oriented South Fork valley segment (from the actively eroding southeast-oriented Chariton River valley) next captured the south- and/or southeast-oriented flood flow in the figure 5 east half while headward erosion of the east and southeast oriented South Fork valley captured flood flow in the figure 5 west half. Flood waters on north ends of beheaded flood flow routes reversed flow direction to erode north-oriented South Fork tributary valleys. At the same time southeast and south-southeast oriented tributary valleys eroded headward from the South Fork valley along and across the south- and southeast-oriented flood flow routes. Headward erosion of the Chariton River and its northeast-oriented tributary valleys next captured the south- and southeast-oriented flood flow. Again flood waters on north ends of beheaded flood flow routes reversed flow direction to erode north-oriented tributary valleys.

Detailed map of Goodwater Creek-Walker Branch drainage divide area

Figure 6: Detailed map of Goodwater Creek-Walker Branch drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

• Figure 6 illustrates a detailed topographic map of the Goodwater Creek-Walker Branch drainage divide area seen in less detail in figure 5 above. The southwest edge of Rathbun Lake, which floods the southeast-oriented Chariton River valley, can be seen in the figure 6 northeast corner. Confidence is the small cluster of buildings in the section 14 center (figure 6 southeast quadrant). Walker Branch is the east-northeast oriented stream flowing from the figure 6 southwest corner and then turning to flow in a southeast direction to the figure 6 south edge (south of Confidence). Note south and southeast oriented Walker Branch tributaries from the north. Goodwater Creek flows in a northeast direction from the figure 6 west center edge to the section 4 southeast quadrant and then turns to flow in a north-northwest direction to the north edge and Rathbun Lake. Note north, north-northwest, and northwest oriented Goodwater Creek tributaries from the south. In section 10 (northwest of Confidence) a shallow northwest-southeast oriented through valley links the valley of a north-northwest oriented Goodwater Creek tributary with the valley of a south-southeast oriented Walker Branch tributary. The valley is defined by three 10-foot contour lines on the west and two contour lines on the east. The through valley provides evidence of a south-southeast oriented flood flow route prior to headward erosion of the deep Goodwater Creek valley. The Goodwater Creek valley eroded headward from the deep southeast-oriented Chariton River valley and the north-northwest oriented Goodwater Creek valley segment and tributary valley were eroded by reversals of flood flow on the north-northwest end of a beheaded flood flow route. The south-southeast oriented flood flow route had been moving water to the actively eroding Walker Branch valley. While relief on the figure 6 upland surface is low evidence of other through valleys can also be found. For example north of Confidence in sections 12, 11, and 2 is a north-northwest and north-northeast oriented Chariton River tributary and shallow through valleys can be seen in section 12 linking that north-northwest oriented tributary valley with a northeast-oriented Chariton River tributary valley to the southeast. These through valleys are defined by a single 10-foot contour line on each side, but provide evidence of at least two south-southeast oriented flood flow routes prior to the reversal of flood flow (caused by headward erosion of the deep Chariton River valley). Valley orientations provide evidence of additional flood flow routes.

South Fork Chariton River-Walnut Creek drainage divide area

Figure 7: South Fork Chariton River-Walnut Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

• Figure 7 illustrates the South Fork Chariton River-Walnut Creek drainage divide area located south and east of the figure 5 map area and west of the figure 3 map area (and includes overlap areas with both figures 3 and 5). Rathbun Dam is located in the figure 7 northeast corner area and Centerville is the town located near the southeast corner. The South Fork Chariton River flows in a northeast direction from the figure 7 west center edge to the north center edge. Walker Branch is the south-southeast oriented tributary flowing from the figure 7 northwest corner. Labeled north-northwest oriented South Fork Chariton River tributaries from the northeast to southwest are Jackson Branch, Sandy Branch, and Carls Creek. Promise City is a town name located along the figure 7 west edge (south half). Walnut Creek flows from the west edge (south of Promise City) to the figure 7 south center area where it turns to flow in a northeast direction to join the Chariton River near the town of Rathbun (located a short distance downstream from Rathbun Dam). Mystic is a town located on the north side of Walnut Creek in the figure 7 east center area and Plano is a small town located north of Walnut Creek in the figure 7 south center area. Clarkdale is a small town in the Walnut Creek valley located between Mystic and Rathbun. Little Walnut Creek is northeast-oriented flowing just north of Plano and making a jog in an east-southeast direction north of Mystic before resuming its northeast-oriented flow to join the Chariton River between Rathbun Dam and the town of Rathbun. Cooper Creek is the northeast-oriented stream flowing across the figure 7 southeast corner (just north of Centerville). Note how orientations of Little Walnut Creek tributaries suggest linkages with the north-northwest oriented South Fork Chariton River tributaries. While through valleys are not deep enough to appear on this 20-meter contour interval map more detailed topographic maps illustrate shallow through valleys linking the north-northwest oriented Jackson Branch valley with the valley of a southeast oriented Walnut Creek tributary and also linking a northwest-oriented Sandy Branch tributary valley with the southeast  and east-oriented Wolf Branch (of Little Walnut Creek) valley. A close look at figure 7 also reveals shallow through valleys linking northwest-oriented Little Walnut Creek tributary valleys with southeast- and east-oriented Walnut Creek tributary valleys (in the region between Clarkdale and Centerville). Detailed topographic maps of the region also reveal additional shallow through valleys. The valley orientations combined with the shallow through valleys provide further evidence that south- and southeast-oriented flood flow was first captured by headward erosion of the Walnut Creek valley, next by headward erosion of the Little Walnut Creek valley, and finally by South Fork Chariton River valley headward erosion.

Walnut Creek-Shoal Creek drainage divide area

Figure 8: Walnut Creek-Shoal Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

• Figure 8 illustrates the Walnut Creek-Shoal Creek drainage divide area south and slightly east of the figure 7 map area and includes overlap areas with figure 7. The south-southeast oriented Chariton River can just barely be seen in the figure 8 northeast quadrant. Plano is located in the figure 8 northwest quadrant, Jerome is a small town located west of the figure 8 center, and Mystic is the town located near the figure 8 north center edge. Walnut Creek flows in an east-northeast direction from the figure 8 west edge (between Plano and Jerome) to Mystic and the figure 8 north edge. Note how Walnut Creek has north and north-northwest oriented tributaries from the south. Numa is a small town located in the figure 8 south center area. Cooper Creek flows in an east direction from the figure 8 west edge between Jerome and Numa and then in a northeast direction to just north of Centerville before turning to flow in an east direction to the Chariton River. Note how Cooper Creek has south-southeast oriented tributaries from the north and how at least some of those tributaries appear to be aligned with north-northwest oriented Walnut Creek tributaries. Also note how Cooper Creek has north-northwest oriented tributaries from the south. Exline is the small town in the figure 8 southeast corner. Shoal Creek is the east-oriented stream near the figure 8 south edge which turns to flow in a south direction west of Exline. Note how Shoal Creek has southeast and south-southeast oriented tributaries from the north and several north and north-northwest tributaries from the south (in addition to some northeast-oriented tributaries). Study of the figure 8 map area reveals a few shallow through valleys crossing drainage divides, although more detailed topographic maps are required to see most evidence of the shallow through valleys. For example shallow through valleys in the Numa area link north-oriented Cooper Creek tributaries with south-oriented Shoal Creek tributaries and a shallow through valley in the Jerome area links a north-oriented Walnut Creek tributary with a south-oriented Cooper Creek tributary. Even on the more detailed topographic maps these shallow through valleys are usually defined by a single 10-foot contour line on each side. The low relief suggests flood waters flowed primarily as large sheets of south-southeast oriented flood flow on an erosion (deposition?) surface at least as high as the present day figure 8 upland surface. Headward erosion of the deep Shoal Creek valley first captured the flood flow and Cooper Creek valley headward erosion beheaded flood flow routes to the newly eroded Shoal Creek valley. Next Walnut Creek valley headward erosion beheaded flood flow movements to the newly eroded Cooper Creek valley.

Shoal Creek-Little Shoal Creek drainage divide area

Figure 9: Shoal Creek-Little Shoal Creek drainage divide area. 

United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

• Figure 9 illustrates the Shoal Creek-Little Shoal Creek drainage divide area south and slightly east of the figure 8 map area and includes overlap areas with figure 8. The west-east oriented Appanoose-Putnam County line (also the Iowa-Missouri state line) is located near the figure 9 south edge. The south-southeast oriented Chariton River is located in the figure 9 northeast corner area. Numa is located in the northwest quadrant and Cooper Creek is the east-oriented stream seen near the figure 9 edge just north of Numa. Shoal Creek is the east-oriented stream just south of Numa and turns to flow in a southeast and south direction to the figure 9 south edge (just east of center) and south of the figure 9 map area turns again to flow in a southeast direction to the south-oriented Chariton River. Cincinnati is a small town near the figure 9 center.  Little Shoal Creek originates just west of Cincinnati and flows in a south-southeast, southeast and east direction around the Strip Mines near the figure 9 south center edge and joins Shoal Creek just south of the south edge. North Creek is an east-southeast oriented Little Shoal Creek tributary flowing from the figure 9 west edge (just south of center) and South Creek is the east-oriented Little Shoal Creek tributary located just to the south. Note how in the figure 9 west center area a north-northwest oriented Shoal Creek tributary is aligned with a southeast-oriented North Creek tributary. Other linkages between Shoal Creek tributaries and Little Shoal Creek tributaries can also be made. Again the map 20-meter contour interval does not show shallow through valleys which in spite of the regional low relief are sometimes visible on more detailed topographic maps. The figure 9 map evidence, based on valley orientations and linkages of north- and south-oriented tributaries, suggests headward erosion of the Little Shoal Creek valley and its east-oriented South Creek and North Creek tributary valleys occurred slightly in advance of headward erosion of the Shoal Creek valley to the north (the south-southeast oriented valley segments may have eroded headward at the same time). Headward erosion of the east-oriented Shoal Creek valley beheaded south- and southeast-oriented flood flow to the newly eroded and actively eroding Little Shoal Creek and tributary valleys with Copper Creek headward erosion next beheading flood flow to the newly eroded Shoal Creek valley.

Chariton River-North Fabius River drainage divide area

Figure 10: Chariton River-North Fabius River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

• Figure 10 illustrates the Chariton River-North Fabius River drainage divide area south and east of the figure 3 map area and east of the figure 9 map area (and includes overlap areas with both figures 3 and 9). Moulton is the town located just north of the figure 10 center. The Chariton River flows in a south-southeast direction from the Sharon Bluffs State Park located in the figure 10 northwest corner to the figure 10 south edge (west of center). The Fox River originates near Moulton and flows in a northeast direction to the figure 10 north edge (east half). North and east of the figure 10 map area the Fox River turns to flow in a southeast direction to join the Mississippi River. The southeast, east, and east-southeast oriented stream originating near Moulton is North Fabius Creek, which flows to the southeast-oriented North Fabius River, which after flowing parallel to the southeast-oriented Middle Fabius River and South Fabius River (headwaters located south of the figure 10 map area) joins those branches to form the Fabius River which then flows to the Mississippi River. The east-oriented stream originating near Moulton is Carter Creek, which east of the figure 10 map area turns to flow in a southeast direction to join the southeast-oriented North Fabius River. West Grove is a small town located in the figure 10 northeast corner. Just south of West Grove are headwaters of an east-northeast oriented stream. That stream east of the figure 10 map area turns to flow in a southeast direction and to become the South Wyaconda River. After flowing parallel to the adjacent southeast-oriented North Wyaconda River the two branches join to form the Wyaconda River, which flows directly to the Mississippi River. What we are seeing in figure 10 is headwaters of multiple closely spaced and parallel southeast-oriented Mississippi River tributaries located almost on the banks of the south-southeast oriented Chariton River. The closely spaced, elongate, and parallel Mississippi River tributary valleys suggests those tributary valleys originated as channels in what was once a large-scale southeast-oriented anastomosing channel complex which eroded headward from the actively developing Mississippi River valley. The figure 10 (and figure 3) evidence suggests headward erosion of the deep south-southeast and south oriented Chariton River valley beheaded and captured those anastomosing southeast-oriented flood flow channels and diverted the southeast-oriented flood flow to the actively eroding Missouri River valley located south of the figure 10 map area.

Additional information and sources of maps studied

This essay has provided only a sample of the detailed topographic map evidence supporting the flood erosion interpretation. Many additional illustrations could be provided. Readers are encouraged to look at mosaics of detailed topographic maps to see the abundance of available data. Maps used in this study were created and published by the United States Geologic Survey and can be obtained directly from the United States Geological Survey and/or from dealers offering United States Geological Survey maps. Hard copy maps can also be observed at United States Geological Survey map depositories which are located throughout the United States and elsewhere. Illustrations used here were created using National Geographic Society TOPO software and digital map data. TOPO software and map data can be obtained from the National Geographic Society and/or dealers offering National Geographic Society digital map data.