Abstract:

Topographic map evidence is used to interpret landform origins in the Chariton River-Grand River drainage divide area located in Lucas, Decatur, and Wayne Counties, Iowa. The Chariton River flows in an east, northeast, and southeast direction in south central Iowa before entering the state of Missouri and then flowing in a south direction to join the Missouri River. West of the south oriented Chariton River segment are south-oriented tributaries to the south, southeast, and south oriented Grand River, which joins the Missouri River a short distance upstream from where the Chariton River joins the Missouri River. Major south-oriented Grand River tributaries originating south of the east oriented Chariton River (or south of east-oriented Chariton River tributaries) from east to west are Locust Creek, Medicine Creek, and the Weldon River, which flows to the south-oriented Thompson River. The south-southeast and south-oriented Thompson River is located west of the Chariton River headwaters and the south-oriented Grand River headwaters are located west of the Thompson River. Valley orientations of these major streams and of their tributaries and the presence of shallow through valleys eroded across drainage divides suggest the south-oriented Chariton River valley and Grand River tributary valleys eroded headward along south-oriented flood flow routes, which were beheaded by headward erosion of east-oriented Chariton River tributary valleys and of the east-oriented Chariton River valley. The south-oriented flood flow is interpreted to have been derived from a rapidly melting thick North American ice sheet located north of the study region. South-oriented flood flow to the newly eroded Chariton River valley was subsequently beheaded by headward erosion of the east, northeast, northwest, and northeast oriented White Breast Creek valley, which eroded headward from the actively eroding Des Moines River valley.

Preface:

Introduction:

• The purpose of this essay is to use topographic map interpretation methods to explore the Chariton River-Grand River drainage divide area landform origins in Lucas, Decatur, and Wayne Counties, 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 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 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-Grand River drainage divide area landform evidence in Lucas, Decatur, and Wayne Counties, Iowa will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm (see menu at top of page for paradigm related essay). This essay is included in the Missouri River drainage basin landform origins research project essay collection.

Chariton River-Grand River drainage divide area location map

Figure 1: Chariton River-Grand River 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 Chariton River-Grand River drainage divide area in Lucas, Decatur, and Wayne Counties, Iowa. The south-southwest and south-southeast oriented river near the figure 1 east edge is the Mississippi River, which eventually flows to the Gulf of Mexico. The state east of the Mississippi River is Illinois. West of the Mississippi River in the north of figure 1 is the state of Iowa and south of Iowa is the state of Missouri. The Missouri River flows in a south-southeast direction from the figure 1 west edge (slightly north of center) to Kansas City and then in an east-northeast direction to Brunswick, Missouri. From Brunswick the Missouri River flows in a southeast and south direction to the figure 1 south center edge. South of the figure 1 map area the Missouri River turns to flow in more of an east direction to join the south-oriented Mississippi River. The state in the figure 1 southwest corner and west of the Missouri River is Kansas and the Nebraska southeast corner can be seen west of the Missouri River and north of Kansas. The Des Moines River is a southeast oriented Mississippi River tributary flowing from the figure 1 north center area to join the Mississippi River along the Iowa-Missouri state line. The Chariton River originates south of Osceola, Iowa (in figure 1 north center area) and flows in an east, southeast, and south direction to join the Missouri River downstream from Brunswick, Missouri. Directly north of the Chariton River in south central Iowa are east and northeast oriented Des Moines River tributaries. The Grand River originates near Afton, Iowa (west of Osceola) and flows in a south, southeast, and south direction to join the Missouri River near Brunswick, Missouri. Several significant south-oriented tributaries flow to the southeast oriented Grand River segment in Missouri. The south-southeast and south oriented Thompson River originates near Greenfield, Iowa (north of Afton) and joins the southeast- and south-oriented Grand River near Utica, Missouri. The south-oriented Weldon River originates just south of the Chariton River headwaters (south of Osceola, Iowa) and joins the Thompson River near Trenton, Missouri. Further east are south-oriented Medicine Creek and Locust Creek, which originate near the Iowa-Missouri state line and which flow to the southeast-oriented Grand River segment upstream from Brunswick, Missouri. The Chariton River-Grand River drainage divide area of concern in this essay is located south of the east- and southeast-oriented Chariton River headwaters in south central Iowa and north of the Iowa-Missouri state line. Essays addressing landform origins in adjacent drainage divide areas include the Platte River-Thompson River drainage divide area in Adair, Union, Ringgold, and Decatur Counties, Iowa essay, the Des Moines River-Missouri River drainage divide area in Madison, Clarke, Lucas, and Monroe Counties, Iowa essay, and the Des Moines River-Grand River drainage divide area in Adair, Madison, Union, and Ringgold Counties, Iowa essay and can be found under Iowa on the side bar category list.

• Drainage routes in the figure 1 map developed as deep valleys eroded headward into the region during immense south-oriented floods. The floods were derived from a rapidly melting thick North American ice sheet, the southern margin of which was located (at the time figure 1 drainage routes developed) north of the figure 1 map area. The ice sheet had been large, probably comparable in size to the present day Antarctic Ice Sheet, and had been located in a deep “hole” created by deep glacial erosion and crustal warping caused by the ice sheet’s great weight. The figure 1 map area was located on the deep “hole’s” south rim and was probably deeply eroded by melt water flood erosion prior to development of present day drainage routes. Initially melt water floods overwhelmed whatever pre-ice sheet drainage system existed and flowed in a south direction across the entire figure 1 map area (and a much larger region) to the Gulf of Mexico. Headward erosion of the deep south-oriented Mississippi River valley and its tributary valleys from the Gulf of Mexico systematically captured the south-oriented flood flow and diverted flood waters to the actively eroding Mississippi River valley. Tributary valleys eroded headward from the actively eroding Mississippi River valley (both to the east and to the west) in sequence from south to north. South of the figure 1 map area in the state of Arkansas headward erosion of the southeast-oriented Arkansas River valley occurred prior to headward erosion of the southeast-oriented White River valley, which occurred prior to headward erosion of the Missouri River valley. Des Moines River valley headward erosion occurred still later.

• Tributary valleys eroded headward from the actively eroding Mississippi River tributary valleys also in sequence (in the figure 1 map area from east to west and from south to north). North-oriented tributary valleys were eroded by reversals of flood flow on north ends of beheaded flood flow channels. Of concern to this essay the south-oriented Chariton River segment eroded headward from actively eroding Missouri River valley along a south-oriented flood flow route and next headward erosion of the southeast-oriented Grand River valley from the actively eroding Missouri River valley captured several south-oriented flood flow routes, including those on the present day Locust Creek, Medicine Creek, Weldon River, Thompson River, and south-oriented Grand River alignments. Deep south-oriented valleys then eroded headward along each of those captured flood flow routes. Because Chariton River valley headward erosion occurred first it was able to erode further north than the Locust Creek, Medicine Creek, and Weldon River valleys and east oriented Chariton River tributary valleys were able to erode headward in sequence (from south to north) to behead south-oriented flood flow to the actively eroding Locust Creek, Medicine Creek, and Weldon River valleys. At the same time Des Moines River valley headward erosion entered the region and reversed flood flow on north ends of beheaded flood flow routes began to capture south-oriented flood waters from west of the actively eroding Des Moines River valley head resulting in the development of east and northeast oriented Des Moines River tributaries which beheaded south-oriented flood flow routes to the actively eroding Chariton River and Thompson River valley (which had earlier beheaded south-oriented flood flow to the south-oriented Grand River tributary valleys.

Chariton River-Grand River drainage divide area detailed location map

Figure 2: Chariton River-Grand River drainage divide area detailed location map. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

• Figure 2 offers a slightly more detailed location map for the Chariton River-Grand River drainage divide area in Lucas, Decatur, and Wayne Counties, Iowa. County names and boundaries are shown. Harrison, Mercer, and Putnam Counties are located in the state of Missouri and the west to east oriented Iowa-Missouri state line is located directly north of them. Ringgold, Decatur, Wayne, and Appanoose Counties are in Iowa and are located directly north of the state line. Chariton Creek originates just north of Weldon (a town on the Clarke-Decatur County line) and flows in an east-northeast, east, and northeast direction to Chariton in Lucas County. Downstream from Chariton the stream is named the Chariton River and flows in a southeast direction across Appanoose County to the Missouri state line and then in a south direction along the Putnam County east border to the figure 2 south edge. South of the figure 2 map area the Chariton River flows to the Missouri River as seen in figure 1. Directly north of the Chariton Creek headwaters in Clarke and Lucas Counties is east- and northeast-oriented White Breast Creek, which is a tributary to the southeast oriented Des Moines River (seen in the figure 2 northeast corner). Wolf Creek is a northeast-oriented tributary joining the Chariton River south of Chariton in Lucas County. The South Fork Chariton River flows in a north direction from near Allerton in Wayne County to  meet southeast oriented Ninemile Creek and then flows in an east and northeast direction to join the Chariton River in the Appanoose County northwest quadrant. Jackson Creek is a north-oriented South Fork Chariton River tributary in eastern Wayne County. South of the Jackson Creek headwaters in the Wayne County southeast quadrant are headwaters of south-oriented Locust Creek, which south of the figure 2 map area flows in a south direction to join the southeast and south oriented Grand River.  South of Bob White State Park and Allerton in south central Wayne County are Medicine Creek headwaters, with Medicine Creek also flowing in a south direction to join the southeast and south oriented Grand River. The south-southeast oriented river flowing from the Decatur County northwest corner to the Harrison County northeast corner and then south along the Harrison-Mercer County line is the Thompson River, which also flows to the southeast and south oriented Grand River. The Weldon River originates just south of Weldon (on Clarke-Decatur County line) and flows in an east direction to the Decatur County northeast corner and then turns to flow in a south direction to the figure 2 south edge. South of the figure 2 map area the Weldon River joins the south-oriented Thompson River, which in turn flows to the Grand River. The Chariton River-Grand River drainage divide in Lucas, Decatur, and Wayne Counties is a drainage divide between the east-oriented Chariton River headwaters and headwaters of south-oriented Grand River tributaries. Stream orientations in the Lucas, Decatur, and Wayne County region provides evidence headward erosion of the east-oriented Chariton River valley (and east-oriented South Fork valley) beheaded south-oriented flood flow channels such as might be found in a south-oriented anastomosing channel complex. The north-oriented South Fork Chariton River tributary valleys were eroded by reversals of flow on north ends of beheaded flood flow routes.

Chariton Creek-Weldon Creek drainage divide area

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

 

• Figure 3 provides a reduced size topographic map of the Chariton Creek-Weldon Creek drainage divide area. Weldon, Iowa is the small town located slightly north and west of the figure 3 center. Van Wert is the small town located near the highway south and west from Weldon. South-oriented streams west of the north-south oriented highway in the figure 3 west half flow to the south-southeast and south oriented Thompson River which is located just west of figure 3. The east-northeast oriented stream originating a short distance west and north of Weldon and flowing to the figure 3 east edge (just south of the northeast corner) is Chariton Creek, which further east becomes the Chariton River and which eventually turns to flow in a south direction to join the Missouri River. The northeast and east-northeast oriented stream originating just north and west of the Chariton Creek headwaters is South White Breast Creek which joins White Breast Creek near the figure 3 north edge and then which flows to the north edge (near northeast corner). North and east of the figure 3 map area White Breast Creek flows in an east and northeast direction to join the southeast-oriented Des Moines River, which flows directly to the Mississippi River. In other words the divide between the Mississippi River drainage basin and the Missouri River drainage basin is located on figure 3 between the east-northeast oriented South White Breast Creek valley and the east-northeast oriented Chariton Creek valley. Weldon Creek originates a short distance west and south of Weldon and flows in an east direction before turning to flow in a south direction to the figure 3 south edge (east half). South of its elbow capture Weldon Creek is named the Weldon River and eventually joins the Thompson River, which flows to the Grand River. The south-oriented stream originating near Van Wert is the Little River, which south of the figure 3 map area flows adjacent to and parallel with the south-southeast oriented Thompson River, but which is a Weldon River tributary. Note the north-oriented Chariton Creek tributary located along the figure 3 east edge and flowing in the opposite direction from the south-oriented Weldon River. The north-oriented Chariton Creek tributary valley was eroded by a reversal of flood flow on the north end of a beheaded south-oriented flood flow route. Headward erosion of the east-oriented Weldon Creek valley also beheaded south-oriented flood flow routes to actively eroding southeast-oriented Weldon River tributary valleys seen in the figure 3 south center area. Headward erosion of the east-northeast oriented Chariton Creek valley next beheaded south-oriented flood flow routes to the newly eroded Weldon Creek (River) valley. Next headward erosion of the White Breast Creek-South White Breast Creek valley beheaded south-oriented flood flow routes to the newly Chariton Creek valley. Weldon Creek, Chariton Creek, South White Breast Creek, and White Breast Creek (north of figure 3) valley headward erosion did not progress far enough west to capture south-southeast oriented flood flow on the present day Thompson River alignment and to some south-oriented Thompson River tributary valleys.

Detailed map of Chariton Creek-Weldon Creek drainage divide area

Figure 4: Detailed map of Chariton Creek-Weldon Creek 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 Chariton Creek-Weldon Creek drainage divide area near Weldon. Weldon is the town located near the figure 4 east edge. Weldon Creek originates in the figure 4 southeast quadrant and flows in an east-southeast  and south-southeast direction to the figure 4 southeast corner. Chariton Creek originates west of the Weldon Creek headwaters and flows in a north and east-northeast direction to the figure 4 east (north half). South White Breast Creek can be seen meandering in an east direction along the figure 4 north edge. Wolf Creek is the south-southwest oriented stream flowing to the figure 4 southwest corner area and flows to south-oriented Long Creek which then flows to the south-southeast oriented Thompson River. While drainage divides in the figure 4 map are relatively level suggesting all valleys were eroded into a flood formed erosion (deposition?) surface, a few shallow through valleys can be seen crossing the South White Breast Creek-Chariton Creek drainage divide. For example in the section 32 northwest quadrant a shallow through valley (defined by one 10-foot contour line on each side) links two north-oriented South White Breast Creek tributary valleys with a south-oriented Chariton Creek valley. While a very subtle feature the shallow through valley provides evidence a south-oriented flood flow route to the actively eroding Chariton Creek valley prior to headward erosion of deep east-oriented South White Breast Creek valley. Headward erosion of the deep White Breast Creek valley beheaded the south-oriented flood flow and flood waters on the north ends of the flood flow routes reversed flow direction to erode north-oriented South White Breast Creek tributary valleys. The north-oriented Chariton Creek headwaters valley was also eroded by a reversal of flood flow on the north end of a beheaded south-oriented flood flow route. Reversed flow on the north end of the beheaded flood flow route captured south-oriented flood flow from west of the actively eroding Chariton Creek valley head, which means the deep Wolf Creek valley (and tributary valleys) did not yet exist west of the Chariton Creek valley head. Headward erosion of the deep Wolf Creek valley and tributary valleys captured south-oriented flood flow west of the Chariton Creek valley while at about the same time South White Breast Creek valley headward erosion ended all Chariton Creek valley headward erosion.

Chariton River-Wolf Creek drainage divide area

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

 

• Figure 5 illustrates the Chariton River-Wolf Creek drainage divide area located south of Chariton, Iowa and east of the figure 3 map area. Chariton is the larger town located near the figure 5 north edge. Humeston is the smaller town near the figure 5 southwest corner and Derby is the small town in the figure 5 west center area. The northeast-oriented stream just seen in the figure 5 northwest corner is White Breast Creek, which north of the figure 5 map area flows in a northeast, northwest, and northeast direction to join the southeast oriented Des Moines River (located north and east of the figure 5 map area). The east and northeast oriented stream flowing from the figure 5 west edge (north of Derby) to Chariton is Chariton Creek and has taken on the name Chariton River by the point where it has reached Chariton. From Chariton the Chariton River flows in a southeast direction to the figure 5 east edge (south half). East and south of figure 5 the Chariton River flows in a south direction to eventually join the Missouri River. Wolf Creek is the northeast-oriented tributary flowing from near Humeston to join the southeast oriented Chariton River downstream from Chariton. The east and southeast oriented Wolf Creek tributary located just south of Derby is Fivemile Creek and will be seen in more detail in figure 6 below. The north-northwest oriented stream just east of Chariton is Little White Breast Creek, which north of the figure 5 map area joins northwest and northeast oriented White Breast Creek. Relief is low in the figure 5 map area and the contour interval for most of the map area is 20 meters, which makes it difficult to identify shallow through valleys crossing drainage divides. Based on valley orientations headward erosion of the deep southeast-oriented Chariton River valley may have captured a developing northeast-oriented flood flow route that was starting to capture southeast- and south-oriented flood flow and to move the flood waters toward the actively eroding Des Moines River valley and the northeast-oriented Wolf Creek valley was later eroded along this former flood flow route. Southeast-oriented Wolf Creek tributary valleys then began to erode headward from the actively eroding northeast-oriented Wolf Creek valley. At the same time an east and northeast oriented flood flow route to the actively eroding Des Moines River valley on the east and northeast Chariton Creek alignment was developing, but that flood flow route was also captured by headward erosion of the deep southeast-oriented Chariton River valley. Headward erosion of the deep Chariton River valley along this newly captured emerging flood flow route beheaded southeast-oriented flood flow routes to the newly eroded Wolf Creek valley and its southeast-oriented tributary valleys. Flood waters on northwest ends of beheaded flood flow routes reversed flow direction to erode northwest and north oriented Chariton Creek (River) tributary valleys. While the above interpretation can probably be significantly improved with further study of more detailed topographic maps, valleys in the figure 5 map area were eroded at a time when headward erosion of deep valleys from the actively eroding Des Moines River valley head and headward erosion of deep valleys from the Missouri River valley to the south were competing with each other to capture the immense south-oriented melt water floods flowing across the figure 5 map area.

Detailed map of Chariton Creek-Fivemile Creek drainage divide area

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

 

• Figure 6 provides a detailed topographic map of the Chariton River-Fivemile Creek drainage divide area east of Derby, Iowa which was seen in less detail in figure 5 above. The east edge of Derby can be seen in section 24 along the figure 6 west edge. The Chariton River is located near the figure 6 north edge and flows in an east direction from section 13 to section 16 before turning to flow in a northeast direction to the figure 6 north edge (east half). Note the north-oriented Chariton River tributaries. The north-oriented tributary valleys were eroded when headward erosion of the deep Chariton River valley beheaded multiple south-oriented flood flow channels. Flood waters on north ends of the beheaded flood flow channels reversed flow direction and eroded the north-oriented valleys. Flood flow channels were beheaded in sequence from east to west and newly reversed flood flow channels captured flood waters still moving south around the actively eroding Chariton River valley head. Such captures of flood water provided the water volumes required to erode the north-oriented tributary valleys. Fivemile Creek flows in a southeast direction in section 25 (figure 6 southwest corner) and then turns to flow in an east-northeast direction to section 29 where it turns to flow in a southeast direction to the figure 6 south edge and then to Wolf Creek (see figure 5). Note short south-oriented Fivemile Creek tributaries. Fivemile Creek valley headward erosion occurred slightly in advance of Chariton River valley headward erosion. Study of the Chariton River-Fivemile Creek drainage divide reveals shallow through valleys linking north-oriented Chariton River tributary valleys with south-oriented Fivemile Creek tributary valleys. For example in the section 19 southeast quadrant and the section 30 northwest quadrant are several shallow through valleys crossing the drainage divide. These north-south oriented through valleys are not deep and are defined by a single 10-foot contour line on each side. In the section 21 southwest corner a slightly deeper through valley is defined by two contour lines on each side. The shallow through valleys provide evidence of south-oriented flood flow channels that existed prior to headward erosion of the deep Chariton River valley. Shallow through valleys can also be seen crossing drainage divides between the north-oriented Chariton River tributaries. For example in the west half of section 20 a shallow through valley crosses the divide between two north-oriented Chariton River tributaries. Such west-east oriented through valleys provide evidence of routes used by captured flood water from west of the actively eroding Chariton River valley head to reach the newly reversed flood flow on the newly beheaded and reversed flood flow route to the east.

Wolf Creek-South Fork Chariton River drainage divide area

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

 

• Figure 7 provides a topographic map of the Wolf Creek-South Fork Chariton River drainage divide area located south and slightly east of the figure 5 map area (and includes overlap areas with figure 5). The Chariton River flows in a southeast direction in the figure 7 northeast quadrant and Rathbun Lake is the reservoir flooding the Chariton River valley. Wolf Creek is the northeast-oriented stream in the figure 7 northwest quadrant and joins the Chariton River just north of the figure 7 north center edge. Southeast-oriented Fivemile Creek flows from the figure 7 west edge to join Wolf Creek near the Lucas-Wayne County line. Note the north-oriented Wolf Creek tributaries. Sugar Creek is the north-northwest oriented Wolf Creek tributary just east of the north-south oriented highway. Just west of the highway is Brush Creek, which flows in a north, northeast, south, east, and north direction to reach Wolf Creek. The South Fork Chariton River flows in an east direction near the figure 7 south edge and flows in a southeast and then northeast direction near the figure 7 southeast corner. East of the figure 7 map area the South Fork joins the Chariton River. Note how most South Fork tributaries from the north are oriented in southeast directions. Millerton is a small town near the north-south oriented railroad line just west of the figure 7 center. East of Millertown are the even smaller communities of New York and Bethlehem. Jordan Creek originates just south of Millerton and flows in an east, north, and east direction to New York and then turns to flow in a southeast direction to join east-oriented South Fork Chariton River. Note how the southeast-oriented Jordan Creek valley is linked by a shallow northwest-southeast oriented through valley with the north-northwest oriented Sugar Creek valley. The through valley is defined by one 20-meter contour line on each side. The 20-meter contour interval makes it difficult to identify other shallow through valleys on the figure 7 map, however study of more detailed topographic maps reveals additional through valleys in the figure 7 map region. Headward erosion of the east-oriented South Fork Chariton River valley captured multiple southeast-oriented flood flow channels prior to headward erosion of the northeast-oriented Wolf Creek valley. As previously noted Wolf Creek valley headward erosion captured south-oriented flood flow prior to headward erosion of the Chariton River valley (north of Wolf Creek) and Chariton River valley headward erosion captured south-oriented flood flow prior to White Breast Creek valley headward erosion.

Detailed map of Sugar Creek-Jordan Creek drainage divide area

Figure 8: Detailed map of Sugar Creek-Jordan Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

• Figure 8 provides a detailed topographic map of the Sugar Creek-Jordan Creek drainage divide area seen in less detail in the figure 7 map area. Millertown is the town located near the south edge (just west of center) Sugar Creek originates just north of Millerton and flows in a north-northeast and north-northwest direction to the figure 8 north edge (west half). Note the north-northwest oriented Sugar Creek tributary originating in the section 9 northwest quadrant and joining Sugar Creek in section 8. Jordan Creek flows in a north-northeast direction from the figure 8 south center edge (near east edge of section 20) and then turns to flow in an east direction to join a southeast-oriented tributary in the section 21 northeast quadrant and then to flow in a southeast direction to the figure 8 south edge (east half). Note how the southeast-oriented Jordan Creek tributary, which flows through section 16, is linked by a shallow through valley with the north-northwest-oriented Sugar Creek valley. The map contour interval is 10 feet and the through valley floor elevation is between 1030 and 1040 feet. Elevations on both sides of the through valley rise to more than 1070 feet. Again, while not deep, the through valley is a water eroded feature and provides evidence of a southeast-oriented flood flow route prior to headward erosion of the deep northeast-oriented Wolf Creek valley. Headward erosion of the deep Wolf Creek valley beheaded the south-oriented flood flow route to what was then the actively eroding southeast-oriented Jordan Creek valley. Flood waters on the north-northwest end of the beheaded flood flow route reversed flow direction to erode the north-northwest oriented Sugar Creek valley. The north-northeast Sugar Creek valley segment was also eroded by reversed flood flow on the north end of the beheaded flood flow route and provides evidence the south-southeast oriented flood flow channel on the Sugar Creek alignment was diverging into two or more south-oriented channels with one channel continuing in a south-southeast direction to the actively eroding Jordan Creek valley and another channel flowing in a south and south-southwest direction to the region just west of Millerton. The north-oriented valley along the figure 8 west edge (south half) is the north-oriented Brush Creek valley (see figure 7). Note shallow west to east oriented through valleys crossing the Brush Creek-Sugar Creek drainage divide in section 18. Those through valleys identify routes used by captured flood water to move to the newly reversed flood flow on the Sugar Creek alignment prior to beheading and reversal of flood flow on the Brush Creek alignment.

South Fork Chariton River-Locust Creek drainage divide area

Figure 9: South Fork Chariton River-Locust Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

• Figure 9 provides a topographic map of the South Fork Chariton River-Locust Creek drainage divide area located south of the figure 7 map area and includes overlap areas with figure 7. Corydon is the larger town on the west to east oriented highway in the figure 9 northwest quadrant. Allerton is the town located south and west from Corydon. Seymour is the town in the figure 9 southeast quadrant. The South Fork Chariton River flows in a north direction from west of Allerton to the figure 9 northwest corner and then in an east, southeast, and northeast direction along the figure 9 north edge. Jackson Creek is the north-oriented tributary joining the South Fork just south of the figure 9 north center edge. West Jackson Creek flows in an east direction from near Corydon to join Jackson Creek just north of the figure 9 center. Note north-oriented West Jackson Creek tributaries from the south and south-oriented West Jackson Creek tributaries from the north. Walnut Creek is the east-oriented stream located between the South Fork and Seymour (east of Jackson Creek). East of the figure 9 map area Walnut Creek flows in an east-northeast direction to join the southeast oriented Chariton River. Note the north-oriented Walnut Creek headwaters and tributary west and north of Seymour. The south-oriented streams flowing to the south edge of the figure 9 southeast quadrant are headwaters of south-oriented Locust Creek. South of the figure 9 map area Locust Creek flows in a south direction roughly parallel to the south-oriented Chariton River to eventually join the Grand River, which then flows to the Missouri River (see figure 1). South-oriented streams flowing to the south edge of the figure 9 southwest quadrant are headwaters of south-oriented Medicine Creek, which south of the figure 9 map area flows in a south direction to join the southeast and south oriented Grand River. The north-oriented Walnut Creek headwaters and tributary valleys and the north-oriented Jackson Creek valley were eroded by reversals of flood flow on north ends of beheaded south-oriented flood flow routes to what was then the actively eroding Locust Creek valley system. Further west the north-oriented West Jackson Creek tributary valleys and the north-oriented South Fork Chariton River headwaters valley were eroded by reversals of flood flow on north ends of beheaded south-oriented flood flow routes. Figure 9 map evidence in the form of valley orientations demonstrates headward erosion of east-oriented tributary valleys from the what was then the actively eroding southeast and south oriented Chariton River valley beheaded multiple south-oriented flood routes to what were then actively eroding south-oriented Grand River tributary valleys.

Detailed map of West Jackson Creek-East Fork Medicine Creek drainage divide area

Figure 10: Detailed map of West Jackson Creek-East Fork Medicine Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

• Figure 10 provides a detailed topographic map of the West Jackson Creek-East Fork Medicine Creek drainage divide area east of Allerton, Iowa. Allerton is located near the west edge of the figure 10 southwest quadrant. West Jackson Creek flows in an east direction from the figure 10 west center edge across section 2 to section 1 where it turns to flow in a north direction to the figure 10 north center edge. Just north of figure 10 West Jackson Creek turns to flow in an east-northeast and east-southeast direction and can just barely be seen again near the figure 10 northeast corner. North-oriented streams flowing to section 32 in the figure 10 northeast corner are West Jackson Creek tributaries. South-oriented streams flowing to the figure 10 south edge are headwaters of south-oriented East Fork Medicine Creek, which flows to south-oriented Medicine Creek. The map contour interval is 10 feet and relief along the drainage divide is very low suggesting south-oriented flood flow moved across a flood formed erosion (deposition?) surface prior to headward erosion of the present day deep valleys. A close look at figure 10 does reveal evidence of what were once south-oriented flood flow channels to the actively eroding south-oriented East Fork Medicine Creek valley system. East of Allerton in the figure 12 northwest quadrant a shallow through valley links a north-oriented West Jackson Creek tributary valley with a south-oriented East Fork Medicine Creek headwaters valleys. The through valley appears to be narrow and appears to be defined by a single contour line on each side. However, further study of the figure 10 map reveals still higher elevations in the Allerton area and in the section 7 northeast quadrant suggesting instead of being narrow the through valley was almost three miles wide (the sections are one mile squares). While definitely not deep a three-mile wide valley provides evidence south oriented flood waters eroded broad flood flow channel into the surface on which the flood waters were flowing. Headward erosion of the east-oriented West Jackson Creek valley beheaded that south-oriented flood flow channel and the north-oriented West Jackson Creek valley segment seen in figure 10 was eroded by a reversal of flood flow on the north end of the beheaded flood flow channel. The east-oriented West Jackson Creek valley segment north of Allerton was eroded by captured flood flow, which had moved south-west of the actively eroding east-oriented West Jackson Creek valley head (just north of figure 10 center) and which was diverted to the newly reversed flood flow on the north-end of the beheaded south-oriented flood flow route.

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.