Abstract:

This essay uses topographic map evidence to interpret landform origins in the Tarkio River-Nodaway River drainage divide area located in Atchison, Holt, and Nodaway Counties of northwest Missouri. The Tarkio and Nodaway Rivers are two of several rivers which originate in southwest Iowa and flow in south-southwest and/or south directions to join the southeast-oriented Missouri in northwest Missouri. These south-oriented Missouri River tributaries are closely spaced and have narrow elongate drainage basins where tributaries often flow parallel to trunk streams for considerable distances. The south-oriented Missouri River tributary valleys are interpreted to have originated as channels in what was once a large south-oriented anastomosing channel complex which eroded headward from what was then the actively eroding Missouri River valley head. The south-oriented anastomosing channel complex captured massive flood flow from what was probably a south-southeast or southeast oriented anastomosing channel complex. Flood waters were derived from a rapidly melting thick North American ice sheet, the southern margin of which was located north of the study region at the time the Tarkio and Nodaway River drainage basins were eroded. Topographic map evidence supporting this flood origin interpretation includes trunk stream and tributary orientations, including numerous barbed tributaries, and shallow through valleys eroded across present day drainage divides.

Preface

The following interpretation of detailed topographic map evidence is one of a series of essays describing similar evidence for all major drainage divides contained within the Missouri River drainage basin and for all major drainage divides with adjacent drainage basins. The research project is interpreting evidence in the context of a previously unexplored deep glacial erosion paradigm, which is fundamentally different from most commonly accepted North American glacial history interpretations. 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.

Introduction

• The purpose of this essay is to use topographic map interpretation methods to explore the Tarkio River-Nodaway River drainage divide area landform origins in Atchison, Holt, and Nodaway 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 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 Tarkio River-Nodaway River drainage divide area landform evidence in Atchison, Holt, and Nodaway Counties, Missouri 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.

Tarkio River-Nodaway River drainage divide area location map

Figure 1: Tarkio River-Nodaway 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 Tarkio River-Nodaway River drainage divide area in Atchison, Holt, and Nodaway Counties, Missouri. The Missouri River flows in a south-southeast direction from the figure 1 north edge to Kansas City near the figure 1 south edge and then turns to flow in an east-northeast direction before turning again to flow in a southeast and south direction to the figure 1 south edge (just west of southeast corner-east of the figure 1 map area the Missouri River flows in an east direction to join the south-oriented Mississippi River). The Missouri River in figure 1 forms the boundary between the states of Nebraska (north) and Kansas (south) to the west and the states of Iowa (north) and Missouri (south) to the east. The Atchison, Holt, and Nodaway County area in northwest Missouri is located in the extreme northwest corner of Missouri. The Tarkio River originates near Stanton, Iowa and flows in a south and south-southwest direction through Coin, Iowa and Tarkio, Missouri before joining the Missouri River. The Nodaway River is somewhat longer and originates near Casey, Iowa (near figure 1 north edge, east of center) and flows in a south-southwest and south direction to Clarinda, Iowa and Skidmore, Missouri before joining the Missouri River. This essay uses topographic map evidence to interpret landform origins in the region between the Tarkio River and Nodaway River south of the Iowa-Missouri state line. Note in the figure 1 map area how most Missouri River tributaries in southwest Iowa and northwest Missouri are oriented south or south-southwest directions. Also note in the figure 1 northeast corner area a southeast-oriented river, which is the Des Moines River. Note how Des Moines River tributaries are oriented in southeast, east, and northeast directions, which are generally quite different from the Missouri River tributary orientations to the south and west. East of the figure 1 map area the Des Moines River flows in a southeast direction to join the south-oriented Mississippi River at the Iowa southeast corner. The Mississippi River-Missouri River drainage divide can be identified by orientations of the respective river tributaries and represents a major landform deserving an explanation.

• Topographic map evidence in this essay and in previous essays indicates the Tarkio River-Nodaway River drainage divide area in Atchison, Holt, and Nodaway Counties, Missouri was eroded by immense south-oriented floods. Essays describing drainage divide areas west of the Missouri River and drainage divides between Missouri River tributaries located in western Iowa and northwest Missouri are listed under Iowa, Missouri, IA Missouri River, and MO Missouri River on the sidebar category list. Flood waters were derived from a rapidly melting thick ice sheet, which at the time the Tarkio and Nodaway River drainage basins were eroded was located north of the figure 1 map area (the southern margin at that time was probably located in southeast South Dakota and southwest Minnesota). At that time supra glacial melt water rivers were carving giant ice-walled (and eventually bedrock-floored) canyons into the decaying ice sheet’s surface. One of the largest ice-walled canyons was located in eastern South Dakota and had a drainage area that extended north and northwest into what is now North Dakota, southern Saskatchewan, and east central Alberta. The northeast and east facing Missouri Escarpment represents what remains of that giant ice-walled and bedrock-floored canyon’s southwest and west wall. Essays illustrating and discussing topographic map evidence related to the southern end of that giant ice-walled and bedrock-floored canyon can be found listed in under James River on the sidebar category list. The south-southeast oriented Missouri River valley in figure 1 map area eroded headward along the immense south and -southeast oriented melt water river emerging from the mouth of that giant ice-walled and bedrock-floored canyon.

• The important thing to remember when trying to understand the figure 1 drainage history is the figure 1 drainage routes did not exist until quite late in the ice sheet’s melt down history. The ice sheet had been thick, comparable in size to the present Antarctic Ice Sheet if not larger, and had been located in a deep “hole”. The deep “hole” had been created by deep glacial erosion and by crustal warping caused by the ice sheet’s tremendous weight. The figure 1 map area was located near the southern rim of that deep “hole” and was probably deeply eroded by repeated south-oriented melt water floods prior to the time the surface now seen was developed. How much material was removed from the figure 1 map area is difficult if not impossible to determine, however hundreds of meters of bedrock may have been stripped as flood waters repeatedly crossed the region. At the same time the melt water floods probably deposited various types of flood transported debris including large ice-rafted boulders, which make it difficult to accurately determine ice sheet margin locations. The immense south-oriented melt water floods repeatedly overwhelmed whatever drainage routes existed, which resulted in temporary ponding of flood waters and deposition of fine-grained sediments included in the immense melt water floods, although topographic map evidence alone is usually not adequate to identify melt water flood deposited materials.

• The figure 1 drainage system probably evolved as the deep south-oriented Mississippi River valley eroded headward from the Gulf of Mexico and deep southeast and east oriented tributary valleys eroded headward from that evolving Mississippi River valley. Headward erosion of the southeast and east-oriented Mississippi River tributary valleys captured the south-oriented melt water floods in sequence from the south to the north. For example, Arkansas River valley headward erosion captured south-oriented flood flow prior to White River valley headward erosion, which captured south-oriented flood flow prior to Missouri River valley headward erosion. Des Moines River valley headward erosion was in the process of capturing south-oriented flood flow moving to the newly eroded Missouri River valley, but failed to do so because the deep Missouri River valley was able to erode in a north-northwest direction along the immense melt water river emerging the previously mentioned ice-walled and bedrock-floored canyon mouth. Prior to headward erosion of the south-southeast oriented Missouri River valley seen in figure 1 the flood waters had been moving in south-southeast and southeast directions toward the actively eroding “east” oriented Missouri River valley located in the state of Missouri and the actively eroding Des Moines River valley in eastern and central Iowa. As the south-southeast oriented Missouri River valley eroded headward across the figure 1 map area south and south-southwest oriented tributary valleys eroded headward in sequence from east to west to capture those south-southeast and southeast oriented flood waters and to divert the flood flow to the Missouri River valley.

Detailed Tarkio River-Nodaway River drainage divide area location map

Figure 2: Detailed Tarkio River-Nodaway River drainage divide area location map. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 2 provides a somewhat more detailed location map for the Tarkio River-Nodaway River drainage divide area in Atchison, Holt, and Nodaway Counties, Missouri. County names and boundaries are shown. Fremont, Page, and Taylor Counties are located in Iowa and the Iowa-Missouri state line is located along their southern boundaries. Atchison, Nodaway, Holt and Andrew Counties are located in Missouri. Counties west of the south-southeast oriented Missouri River are Otoe, Nemaha, and Richardson and are located in Nebraska. The Tarkio River flows in a south-southwest direction through central Page County to Blanchard on the Iowa-Missouri state line and then to Tarkio in Atchison County before joining the Missouri River in the Holt County northwest corner. West Tarkio Creek is the south-southwest oriented tributary joining the Tarkio River near Tarkio. Note how the Tarkio River drainage basin is long and narrow with most major tributaries being parallel to the Tarkio River for significant distances before joining the Tarkio River. The Nodaway River is formed in southeast Page County at the confluence of the south-oriented West Nodaway River and south and south-southwest oriented East Nodaway River. From Page County the Nodaway River flows in a south direction across western Nodaway County and then forms the Holt County east border as it flows to join the Missouri River just south of the figure 2 map area. West of the Tarkio River is the south-oriented Nishnabotna River, which is formed in south central Fremont County at the confluence of the south-oriented West Nishnabotna River and the south-southwest oriented East Nishnabotna River. The remarkable feature of the southwest Iowa and northwest Missouri drainage system is the large number of nearly parallel south and south-southwest oriented Missouri River tributaries and tributaries to those tributaries. The converging south and south-southwest oriented river valleys probably originated as channels in what was once a large south and/or south-southwest oriented anastomosing channel complex. While not obvious from the figure 2 map evidence this south and/or southwest oriented anastomosing channel complex probably evolved as headward erosion of the deep Missouri River valley captured what had been south-southeast and southeast oriented flood flow moving to actively eroding deep valleys further to the east. Evidence for the south-southeast and southeast oriented flood flow is more subtle and must be seen on topographic maps.

Tarkio River-Nodaway River drainage divide area northeast of Tarkio, Missouri

Figure 3: Tarkio River-Nodaway River drainage divide area northeast of Tarkio, Missouri. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 3 illustrates the Tarkio River-Nodaway River drainage divide area northeast of Tarkio, Missouri. Tarkio is the town located in the figure 3 southwest corner region. The south-southwest oriented Tarkio River flows from the figure 3 north edge (slightly west of center) to the figure 3 southwest corner. South-oriented West Tarkio Creek joins the south-southwest oriented Tarkio River at Tarkio. Middle Tarkio Creek is the south-southwest oriented stream located between West Tarkio Creek and the Tarkio River and which joins West Tarkio Creek just north of Tarkio. Note how Tarkio River tributaries from the east are often oriented in northwest directions and join the south-southwest oriented Tarkio River as barbed tributaries. Short northwest-oriented tributary valleys can also be seen along east sides of the Middle Tarkio Creek and West Tarkio Creek valleys. These northwest-oriented tributary valleys are evidence the Tarkio River valley and subsequently the Middle Tarkio Creek valley and still later the West Tarkio Creek valley eroded headward across multiple southeast-oriented flood flow channels. The northwest-oriented tributary valleys were eroded by reversals of flood flow along northwest ends of beheaded flood flow routes. The north-south (with a jog) oriented Atchison-Nodaway County line is shown and labeled and is just east of the figure 3 center. The southwest and south oriented river near the figure 3 east edge is the Nodaway River. Burlington Junction is the town located on the east bank of the Nodaway River valley in the figure 3 southeast quadrant. Mill Creek is the south-oriented tributary joining the Nodaway River just west of Burlington Junction. Elmo is the small town located in the Mill Creek valley. The railroad line extending from Burlington Junction to Elmo and then in a northwest direction to the figure 3 north edge follows the valley of a southeast-oriented Mill Creek tributary and then the valley of a northwest-oriented Tarkio River tributary. The two valleys are linked by a shallow northwest-southeast oriented through valley in which the railroad line is located. The through valley provides evidence of a southeast-oriented flood flow channel to what was once the actively eroding Mill Creek tributary valley. At that time the deep Tarkio River valley did not exist and flood waters flowed freely across a surface as high as the present day divides. Headward erosion of the deep Tarkio River valley beheaded and reversed flood flow on the southeast-oriented flood flow channel, which then eroded the northwest-oriented Tarkio River tributary valley. A close look at the figure 3 map reveals many additional such through valleys. The through valleys are best seen on more detailed topographic maps such as figure 4 below.

Detailed map of Tarkio River-Mill Creek drainage divide area

Figure 4: Detailed map of Tarkio River-Mill 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 Tarkio River-Mill Creek drainage divide area along the railroad line seen in less detail in figure 3 above. The west to east oriented Iowa-Missouri state line is located near the figure 4 north edge and Blanchard is the small town straddling the state line (west half). The south-southwest oriented Tarkio River is located in the figure 4 northwest quadrant. Mill Creek flows in a south-southeast direction near the figure 4 east edge. A northwest-southeast oriented railroad line extends from Blanchard to the figure 4 southeast corner. Note how the railroad line follows the valley of a northwest-oriented Tarkio River tributary to the drainage divide located in the section 3 southeast corner and then follows the valley of a southeast-oriented Mill Creek tributary to the figure 4 southeast corner. The railroad crosses the drainage divide in the section 3 southeast corner on the floor of a shallow northwest-southeast oriented through valley linking the northwest-oriented Tarkio River tributary valley with the southeast-oriented Mill Creek valley. The map contour interval is ten feet and the elevation where the railroad crosses the drainage divide is between 1130 and 1140 feet. The hills on either side of the through valley rise to elevations greater than 1170 feet. A 30-40 foot deep valley is not spectacular evidence, but is evidence of a southeast-oriented flood flow channel that once moved flood water to what was at that time the actively eroding southeast-oriented Mill Creek tributary valley. Study of the figure 4 map area reveals many additional shallow through valleys. An interesting set of shallow through valleys can be seen in section 8 (figure 4 southwest quadrant) linking northwest-oriented Tarkio River tributary valleys with a southwest (and northwest) oriented Tarkio River tributary valley (where the northwest-oriented segment is just west of the figure 4 map area). At least five northwest-southeast oriented shallow through valleys can be seen in section 8 alone. The through valleys are generally defined by two or three contour lines on each side and provide evidence of multiple southeast-oriented flood flow routes that carried flood waters to what was then the actively eroding southwest and northwest oriented tributary valley prior to headward erosion of the deep Tarkio River directly to the west. Headward erosion of the deep tributary valley and the deep Tarkio River valley probably occurred at approximately the same time, although the tributary valley eroded headward slightly in advance of the Tarkio River valley. Additional similar through valleys cross the drainage divide in section 17.

Tarkio River-Nodaway River drainage divide area southeast of Tarkio, Missouri

Figure 5: Tarkio River-Nodaway River drainage divide area southeast of Tarkio, Missouri. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 5 illustrates the Tarkio River-Nodaway River drainage divide area south of the figure 3 map area and includes overlap areas with figure 3. Tarkio, Missouri is located just west of the figure 5 northwest corner and the Tarkio River flows in a south-southwest direction across the figure 5 northwest corner. The south-oriented Nodaway River can be seen along the figure 5 east edge (north half). The south-southwest and south oriented stream flowing from the figure 5 north center edge to the figure 5 south edge (west half) is Little Tarkio Creek. Long Branch is the labeled south-oriented tributary joining Little Tarkio Creek in the figure 5 southeast corner region. South of the figure 5 map area Little Tarkio Creek flows as an independent stream parallel to the Tarkio River to the southeast-oriented Missouri River valley. The labeled south-southwest oriented stream between Little Tarkio Creek and the Nodaway River is the East Fork of Little Tarkio Creek and joins Little Tarkio Creek south of the figure 5 map area. Note how the Tarkio River in the figure 5 northwest quadrant has several northwest-oriented tributaries and how some Little Tarkio Creek and East Fork tributary valleys are oriented in southeast and northwest directions. Again shallow through valleys can be seen crossing drainage divides. On figure 5 the through valleys are hard to identify, but with a close look they can be seen. Easier to see through valleys on figure 5 link the south-oriented Long Branch valley with northwest-oriented Tarkio River tributary valleys. The map contour interval is ten meters and these through valleys are defined by two contour lines on each side. Through valleys link the south-oriented Long Branch valley with at least three different northwest-oriented Tarkio River tributary valleys. South of the figure 5 map area Little Tarkio Creek and the Tarkio River valleys converge in the larger Missouri River valley. The through valleys linking the northwest-oriented Tarkio River tributary valleys with the south-oriented Long Branch-Little Tarkio River valley provide evidence of diverging and converging flood flow channels typical of anastomosing channel complexes. In other words, prior to headward erosion of the deep Tarkio River valley a complex of south-oriented anastomosing flood flow channels crossed the figure 5 map area. Headward erosion of the deep Tarkio River valley beheaded the diverging flood flow channels carrying south-oriented flood waters to what was then the actively eroding Little Tarkio Creek-Long Branch valley. Close study of the figure 5 map area and adjacent areas reveals other evidence of former diverging and converging flood flow channels.

Detailed map of Tarkio River-Long Branch drainage divide area

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

Figure 6 provides a more detailed topographic map of the Tarkio River-Long Branch drainage divide area seen in less detail in figure 5 above. Tarkio is the town in the figure 6 northwest corner. The Tarkio River flows in a south-southwest direction to the figure 6 southwest corner. The south-oriented tributary joining the Tarkio River near Tarkio is West Tarkio Creek. Little Tarkio Creek flows in a south-southwest direction across the figure 6 southeast corner. Long Branch flows in a south-southwest direction from section 28 (figure 6 east center area) to the figure 6 south center edge. Of particular interest to this discussion are the south-oriented Long Branch tributary in section 31 and the southeast-oriented Long Branch tributary in the section 6 northwest quadrant. Note how those tributary valleys are linked by multiple shallow through valleys with northwest oriented Tarkio River tributary valleys. The map contour interval is ten feet. The north-south oriented through valley in the section 30 southeast quadrant is defined by four contour lines on each side (more on the east side). The through valley in the section 31 northwest quadrant is also defined by four contour lines on each side. Two through valleys in the section 36 southeast quadrant are shallower, but are easy to identify. Also note how the north and northwest oriented Tarkio River tributary originating in sections 20 and 21 is linked by multiple through valleys with the south-southwest oriented Long Branch headwaters valley. Another shallow through valley in the section 28 northeast corner links the south-southwest oriented Long Branch headwaters valley with still another north (and northwest) oriented Tarkio River tributary valley (where the northwest-oriented valley segment is north of the figure 6 map area). These through valleys provide evidence of multiple diverging and converging flood flow channels. Also look at the Long Branch-Little Tarkio Creek drainage divide in sections 27, 28, and 33 and note the multiple northwest-southeast oriented shallow through valleys crossing that drainage divide. The northwest-southeast orientation of many of the through valleys and also of many secondary tributary valleys suggests headward erosion of the major south-southwest oriented valleys captured southeast-oriented flood flow moving across the figure 6 map area. What probably was taking place was a south and south-southwest oriented anastomosing channel complex was capturing an immense flood which had been moving in a southeast-oriented anastomosing channel complex.

Little Tarkio Creek-Nodaway River drainage divide area

Figure 7: Little Tarkio Creek-Nodaway River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 7 illustrates the Little Tarkio Creek-Nodaway River drainage divide area located east and south of the figure 5 map area and includes overlap areas with figure 5. Skidmore is the town located near the figure 7 southeast corner. Quitman is the smaller town located north of Skidmore near the figure 7 east edge. The Nodaway River flows in a south direction just west of Quitman and Skidmore. Little Tarkio Creek flows in a south-southwest direction from the figure 7 north edge (west half) to the figure 7 southwest corner and is joined by south-southwest and south oriented Long Branch near the figure 7 west center edge. The East Fork Little Tarkio Creek flows from the figure 7 north edge across the figure 7 center area to join Little Tarkio Creek just south of the figure 7 southwest corner. Dotham is the place-name near the figure 7 center and Hickory Branch is the southwest-oriented East Fork tributary flowing through Dotham. The unnamed stream flowing to the figure 7 south center edge is Squaw Creek and Squaw Creek flows as an independent stream to the Missouri River valley located south of the figure 7 map area. Note how many of the longer Nodaway River tributaries from the west (and none of them are very long) are named and are oriented in east and even northeast directions, but also have significant southeast oriented tributaries and/or headwaters. Burr Oak Creek is the east, east-northeast, and east oriented tributary joining the south-oriented Nodaway River just north of Skidmore. Note how east of Dotham the south-southwest oriented Squaw Creek headwaters valley is linked by a shallow through valley with headwaters of an unnamed northeast, southeast, and east oriented Nodaway tributary valley. Study of the figure 7 map area also reveals shallow through valleys eroded across drainage divides. Perhaps the easiest through valleys to see are located in the figure 7 center area and link the south-southwest oriented East Fork valley with the southwest-oriented Hickory Branch valley and especially with a south-southwest oriented Hickory Branch tributary valley.The through valleys provide evidence of diverging and converging flood flow routes typical of anastomosing channel complexes. Figure 8 below provides a detailed topographic map of the Hickory Branch-Burr Oak Branch drainage divide area located south and east of Dotham to better illustrate through valleys in that region. .

Detailed map of Hickory Branch-Burr Oak Branch drainage divide area

Figure 8: Detailed map of Hickory Branch-Burr Oak Branch 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 Hickory Branch-Burr Oak Branch drainage divide area seen in less detail in figure 7 above. Hickory Branch is the labeled southwest-oriented stream located in the figure 8 northwest quadrant (Dotham is located just west of the figure 8 map area in the Hickory Branch valley). West of the figure 8 map area Hickory Branch flows to the south-southwest oriented East Fork Little Tarkio Creek valley. The unlabeled southwest-oriented stream in the section 29 south half and flowing to the figure 8 west edge in section 32 (south of center) is a Little Tarkio Creek tributary. Burr Oak Creek is the labeled east and east-northeast oriented stream in the figure 8 southeast quadrant and east of the figure 8 map area Burr Oak Creek flows to the south-oriented Nodaway River. The unlabeled southwest-oriented stream flowing from section 27 across the section 34 northwest quadrant and the section 33 southeast quadrant to the figure 8 south edge (slightly west of center) is Squaw Creek, which flows independently of Little Tarkio Creek and the Nodaway River to the Missouri River valley (located south of the figure 8 map area). Note how many Squaw Creek tributaries from the northwest are oriented in southeast directions and from the southeast are oriented in northwest directions. Also note how many Hickory Branch tributaries from the southeast are oriented in northwest directions. Further note how Burr Oak Creek tributaries from the north are oriented in southeast directions. Study of the figure 8 map area reveals drainage divides are crossed by numerous northwest-southeast oriented shallow through valleys linking northwest-oriented tributary valleys with southeast-oriented tributary valleys. For example in the section 28 northwest quadrant two parallel through valleys link a northwest-oriented Hickory Creek tributary valley with a southeast-oriented Squaw Creek tributary valley. The map contour interval is ten feet and the deeper through valley is defined by three contour lines on each side. Other similar through valleys can be seen in the same region as well as along the Squaw Creek-Burr Oak Creek drainage divide. A somewhat different and interesting through valley is found near the corner of sections 26, 27, 22, and 23 and links the southwest-oriented Squaw Creek valley with a northeast-oriented Nodaway River tributary valley segment. This through valley suggests that for a time at least south-oriented flood flow from what is today the Nodaway River drainage basin flowed in a southwest direction to what is today the independent Squaw Creek valley and provides further evidence of diverging and converging flood flow channels typical of a large-scale anastomosing channel complex.

Missouri River-Nodaway River drainage divide area

Figure 9: Missouri River-Nodaway River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 9 illustrates the Missouri River-Nodaway River drainage divide area south of the figure 7 map area. The southeast oriented Missouri River flows across the figure 9 southwest quadrant and an east-oriented Missouri River segment can be seen along the south edge of the figure 9 southeast quadrant. Little Tarkio Creek can be seen flowing in a south and south-southeast direction to join the Missouri River channel near the figure 9 west edge. Squaw Creek joins Little Tarkio Creek on the Missouri River valley floor north of the figure 9 northwest corner. Note Missouri River tributary orientations. While some tributaries from the north near the figure 9 south edge are oriented in south directions further upstream tributaries are oriented in southwest and even west directions. Mill Creek in the figure 9 south center area flows to the southeast and east oriented Missouri River valley as a south- and west-oriented (barbed) tributary. Rock Creek and Hickory Creek are significant west-oriented Mill Creek tributaries. Note also north-northeast oriented (barbed) Missouri River tributaries in the figure 9 southwest corner. Drainage routes on the Missouri River valley floor have been significantly altered by human intervention and are ignored for purposes of this discussion. The southeast and south oriented Nodaway River forms the Holt-Andrew County border in the figure 9 east half. Also note the barbed Nodaway River tributaries. For example Nichols Creek in the figure 9 north center area flows in a north and northeast direction to join the south-oriented Nodaway River. Further downstream on the Nodaway River Carroll Branch flows in a north-northeast, northeast, and east direction to join the south-oriented Nodaway River. These barbed tributaries are relics of flood flow routes that once crossed the figure 9 map area. Headward erosion of the deep south-oriented Nodaway River valley beheaded south-oriented flood flow channels on the north-oriented Carroll Branch and Nichols Creek alignments and flood waters on north ends of the beheaded flood flow routes reversed flow direction to erode the north-oriented Carroll Branch and Nichols Creek valleys. At about the same time Missouri River valley headward erosion beheaded east-oriented flood flow channels on the Mill Creek, Hickory Creek, and Rock Creek alignments and flood waters on west ends of those flood flow channels reversed flow direction to erode the west-oriented Mill Creek, Hickory Creek, and Rock Creek valleys. More detailed topographic maps such the map of the Carroll Branch-Smith Creek drainage divide area below show additional evidence supporting this flood origin interpretation.

Detailed map of Carroll Branch-Smith Creek drainage divide area

Figure 10: Detailed map of Carroll Branch-Smith 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 Carroll Branch-Smith Creek drainage divide area seen in less detail in figure 9 above. Carroll Branch flows in a north-northeast direction from section 33 in the figure 10 center to the figure 10 north center edge. Smith Creek originates in the section 4 northwest corner and flows in a southeast and east direction to the figure 10 south edge near the southeast corner. Rock Creek originates in the section 33 southwest corner and flows in a northwest direction across section 32 before flowing in a southwest direction to the figure 10 west edge. As seen in figure 9 Rock Creek west of the figure 10 map area flows in a west direction to join south and west oriented Mill Creek. Note how in the section 33 southwest corner and section 4 northwest corner a shallow through valley links the southeast-oriented Smith Creek headwaters valley with the northwest-oriented Rock Creek headwaters valley. The map contour interval is ten feet and the through valley appears to be defined by four contour lines on either side. Also note in the section 33 south center area a shallow through valley linking the north-northeast oriented Carroll Branch valley with a southeast-oriented Smith Creek tributary valley. In the section 32 northeast corner a through valley links the north-northeast oriented Carroll Branch valley with the valley of southwest-oriented Rock Creek tributary. Study of the figure 10 reveals many similar through valleys providing evidence of what were complicated and ever-changing flood flow channels as the deep Missouri River and Nodaway River valleys eroded headward into and across the regions east and 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.