Missouri River-Osage River drainage divide area landform origins in Moniteau, Cole, and Miller Counties, Missouri, USA

· Missouri, MO Missouri River, Osage River
Authors

Abstract:

Topographic map interpretation methods are used to determine landform origins in the Missouri River-Osage River drainage divide area located in Moniteau, Cole, and Miller Counties, Missouri. The Moniteau, Cole, and Miller County area is located at the Missouri River-Osage River drainage divide east end where the Osage River joins the Missouri River. Between the southeast-oriented Missouri River and northeast-oriented Osage River is the east-northeast oriented Moreau River, which is formed by east-northeast oriented South Moreau Creek and east-southeast oriented North Moreau Creek and which joins the Missouri River upstream from where the Osage River joins the Missouri River. North of North Moreau Creek is east- and northeast-oriented Moniteau Creek, which enters the southeast-oriented Missouri River valley as a barbed tributary. Other north-oriented barbed tributaries also enter the southeast-oriented Missouri River valley. The Osage and Moreau Rivers and North and South Moreau Creeks all exhibit large incised meanders. Barbed tributaries and elbows of capture are common along all study region streams as are shallow through valleys crossing present day drainage divides. These landform features are interpreted to have formed during immense south and southeast-oriented glacial melt water floods, which flowed across the study region as the deep Missouri River valley and its tributary valleys eroded headward into and across the region. Osage River valley headward erosion proceeded slightly in advance of Moreau River-South Moreau Creek valley headward erosion, which was slightly in advance of North Moreau Creek valley headward erosion. Moniteau Creek valley headward erosion next beheaded flood flow routes to the newly eroded North Moreau Creek valley and Missouri River valley and tributary valley headward erosion subsequently captured all flood flow routes to the newly eroded Moniteau Creek valley. North-oriented valley segments and tributary valleys were eroded by reversals of flood flow on north ends of beheaded flood flow routes.

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 Missouri River-Osage River drainage divide area landform origins in Moniteau, Cole, and Miller 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 Missouri River-Osage River drainage divide area landform evidence in Moniteau, Cole, and Miller 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.

Missouri River-Osage River drainage divide area location map

Figure 1: Missouri River-Osage 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 is a location map for the Missouri River-Osage River drainage divide area in Moniteau, Cole, and Miller Counties, Missouri and shows a large region in the state of Missouri. The state of Illinois is east of the south-southeast oriented Mississippi River, which forms the Missouri-Illinois border. Kansas is the state west of Missouri along the figure 1 west edge. The Missouri River flows in an east-northeast direction from Kansas City (near figure 1 west center edge) to Brunswick and then turns to flow in a southeast, south, east, and southeast direction to Jefferson City. From Jefferson City the Missouri River flows in an east-northeast, east, southeast, and northeast direction to join the south-oriented Mississippi River near St Louis. The Osage River flows in an east and northeast direction from near Schell City (near figure 1 southwest corner) to Harry S. Truman Reservoir and then to the Lake of the Ozarks before flowing in a northeast direction to join the Missouri River a short distance downstream from Jefferson City. The Missouri River-Osage River drainage divide area in Moniteau, Cole, and Miller Counties is located at the east end of the Missouri River-Osage River drainage divide area and is east of a line extending north from Bagnell Dam (behind which is the Lake of the Ozarks) through Eldon and California to the southeast-oriented Missouri River. The unlabeled drainage route between the Missouri River and Osage River with two tributaries and flowing to the Missouri River at Jefferson City is the Moreau River. The northern Moreau tributary is North Moreau Creek and the southern tributary is South Moreau Creek. The unlabeled east-oriented Missouri River tributary north of North Moreau Creek is Moniteau Creek. Essays illustrating and describing surrounding drainage divide regions can be found under MO Missouri River and/or Osage River on the sidebar category list.
  • Topographic map evidence illustrated in this essay and in hundreds of other Missouri River drainage basin landform origins research project essays documents figure 1 drainage routes were established as deep valleys eroded headward into the figure 1 map area to capture immense south-oriented glacial melt water floods. Flood waters were derived from a rapidly melting thick North American ice sheet, which at the time figure 1 drainage routes were established, was located north of the figure 1 map area. Initially flood waters over whelmed whatever drainage systems existed and flowed south across the entire figure 1 map area to the Gulf of Mexico. The Ozark Plateau, located south of the figure 1 map area, was probably uplifted as flood waters flowed across the region and that uplift contributed to massive flood flow reversals responsible for erosion of north-oriented Missouri and Osage River tributary valleys. Uplift was probably delayed crustal warping triggered by the ice sheet’s great weight and prior to the uplift there were no major topographic barriers between the figure 1 map area and the Gulf of Mexico. Deep flood water erosion of the Ozark Plateau region may also have contributed to the regional uplift. Headward erosion of the deep 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 Mississippi River valley. Mississippi River tributary valleys were eroded in sequence from south to north and west of the Mississippi River in sequence from east to west. For example, in the state of Arkansas, south of the figure 1 map area, headward erosion of the southeast-oriented Arkansas River valley and its tributary valleys captured south-oriented flood flow routes prior to those flood flow routes being beheaded by headward erosion of the southeast-oriented White River valley and its tributary valleys. Next south-oriented tributary valleys eroded headward from the newly eroded White River valley along and across flood flow routes into what is now southern Missouri (just south of the figure 1 map area).
  • Headward erosion of the deep Missouri River valley and its tributary Osage River valley next captured the south oriented flood flow routes and flood waters on north ends of the beheaded flood flow routes reversed flow direction to erode what are today north-oriented Missouri River and Osage River tributary valleys. Flood flow routes were beheaded one at a time and in sequence from east to west, which meant reversed flood flow on a newly beheaded flood flow route could capture yet to be beheaded flood flow from flood flow routes further to the west. Such captures of yet to be beheaded flood flow provided the water volumes required to erode significant north-oriented valleys. As already mentioned these massive flood flow reversals were also probably significantly aided by Ozark Plateau uplift, which most likely was occurring at the same time. In the case of the Missouri River-Osage River drainage divide area headward erosion of the deep Osage River valley from the Jefferson City region was slightly in advance of Missouri River valley headward erosion, which beheaded flood flow routes to the newly eroded Osage River valley. The deep Missouri River valley, at least for a time eroded headward from the Jefferson City area along south and southeast-oriented flood flow routes while the deep Osage River valley eroded headward primarily across south and southeast oriented flood flow routes. In addition to crustal warping occurring as the deep valleys eroded headward across the region, it is important to remember flood flow volumes were immense and were deeply eroding the entire region. Evidence shown in this essay and in other Missouri River drainage basin landform origins research project essays documents all Missouri River drainage divides in the figure 1 map area were eroded by these massive south-oriented floods and the flood waters were responsible for eroding all regional slopes seen today.

Detailed location map for Missouri River-Osage River drainage divide area

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

 

  • Figure 2 depicts a detailed location map for the Missouri River-Osage River drainage divide area located in Moniteau, Cole, and Miller Counties, Missouri. County boundaries and names are given. The Missouri River flows in a southeast direction along the northeast borders of Cooper, Moniteau, and Cole Counties and then turns to flow in a northeast and east direction along the Osage County northern border. The large reservoir in the figure 2 southwest quadrant is the Lake of Ozarks and is flooding the Osage River valley. From Bagnell Dam along the Miller County west border the Osage River meanders in a northeast direction across Miller County and the Cole County southeast corner before meandering along the Cole County-Osage County border to join the northeast-oriented Missouri River. Note how the northeast-oriented Osage River route is characterized by large meanders while the southeast-oriented Missouri River does not show comparable meanders. Probably the large Osage River meanders were formed as the deep Osage River valley first eroded headward along a reversed flood flow route, then eroded headward along a captured (yet to be beheaded flood flow route) and perhaps even eroded headward for short distances along a yet to beheaded flood flow route before eroding headward again along a reversed flood flow route. The Missouri River valley lack of comparable meanders probably means the deep Missouri River valley eroded headward along and across south oriented flood flow routes. The Moreau River meanders in an east direction in Cole County (just south of Jefferson City) to join the Missouri River a short distance downstream from Jefferson City and is formed at the confluence of North and South Moreau Creeks. North Moreau Creek is formed in western Moniteau County by north and east-oriented tributaries and flows in a north direction before turning to meander in a southeast direction to join South Moreau Creek. South Moreau Creek originates near Eldon in northwest Miller County and meanders in a northeast direction into Cole County where it joins North Moreau Creek to form the Moreau River. North of North Moreau Creek is east-oriented Moniteau Creek, which originates in southeast Cooper County and which flows across northern Moniteau County to join the Missouri River. Headward erosion of the meandering Osage River valley as already mentioned proceeded slightly in advance of Moreau River valley headward erosion. South Moreau Creek valley headward erosion beheaded south and southeast oriented flood flow routes to the newly eroded Osage River valley. Next North Moreau Creek valley headward erosion beheaded flood flow routes to the newly eroded South Moreau Creek valley. Moniteau Creek valley headward erosion (from the actively eroding Missouri River valley head) then beheaded south-oriented flood flow routes to the  newly eroded North Moreau Creek valley.

East end of Missouri River-Osage River drainage divide area

Figure 3: East end of Missouri River-Osage River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

  • Figure 3 provides a topographic map of the east end of the Missouri River-Osage River drainage divide area. Jefferson City is the urban area straddling the north edge of the figure 3 northwest quadrant and is located along the southwest bank of the southeast and northeast-oriented Missouri River, which flows to the figure 3 northeast corner. Osage City is the much smaller town located near the figure 3 northeast corner. The Osage River flows in a north-northwest direction from the figure 3 south center edge and then turns to flow in a southeast and east-northeast direction before turning to flow again in a north-northwest direction and then northeast direction to join the Missouri River north and east of the figure 3 northeast corner. The north-northwest oriented Osage River valley segments were eroded headward along north ends of beheaded flood flow routes and the short southeast-oriented Osage River valley segment was eroded headward along a yet to be beheaded flood flow route. The east- and northeast-oriented Osage River valley segments were eroded headward across south and southeast-oriented flood flow routes. Between Jefferson City and the Osage River is the meandering Moreau River, which meanders in an east and east-northeast direction to join the Missouri River between Jefferson City and Osage City. Note how Moreau River meanders frequently include north and/or northwest oriented valley segments in addition to south and/or southeast oriented valley segments. North and northwest-oriented Moreau River valley segments were probably eroded headward along north ends of beheaded and reversed flood flow routes while the south and southeast-oriented valley segments were probably eroded headward along yet to be beheaded flood flow routes. Headward erosion of the Moreau River valley occurred at approximately the same time as headward erosion of the deep Missouri River valley to north and was probably influenced by flood flow reversals on north ends of newly reversed flood flow routes, which had been beheaded by Missouri River valley headward erosion. Apparently Moreau River valley headward erosion proceeded fast enough that it was able to keep slightly in advance of the Missouri River valley head to the north, but not far enough in advance to escape the influence of the alternating flood flow directions created as the deep Missouri River valley eroded headward across the region.

Detailed map of Moreau River-Osage River drainage divide area

Figure 4: Detailed map of Moreau River-Osage 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 Moreau River-Osage River drainage divide area seen in less detail in figure 3. Wardsville is the small town located west of the figure 4 center. The Moreau River meanders in an east direction across the figure 4 north half with meanders crossing the figure 4 west and north edges. The Osage River flows in a north-northwest direction from the figure 4 south center and then makes a U-turn to flow in a southeast direction to the figure 4 south edge (east half). In addition to orientations of the Osage River and Moreau River valley segments what other evidence suggests the region was crossed by south and/or southeast-oriented flood flow channels? Look at the drainage divide between the southeast-oriented Moreau River valley segment in section 5 and the southeast-oriented Osage River valley segment in section 16. In section 8 there is a shallow northwest-southeast oriented through valley crossing the drainage divide. The map contour interval is 20 feet and the low points along the drainage divide in section 8 are between 740 and 760 feet. Follow the drainage divide to the west and elevations rise to 827 feet in section 7 (see spot elevation). Follow the drainage divide east from the through valley and elevations rise to 830 feet in section 9 (see spot elevation). The through valley provides evidence of what was once a southeast-oriented flood flow channel at least 67 feet deep and probably much deeper. The southeast-oriented Osage River and Moreau River valley segments were eroded headward along short segments of that southeast-oriented flood flow channel. Next proceed west into section 7 and look at the drainage divide in the town of Wardsville. Note how Herbrandt Branch flows in a north-northwest direction from the south half of section 7 to join a northwest-oriented Moreau River valley segment near the figure 4 northwest corner. Note also how the Herbrandt Branch alignment is the same as the north-northwest oriented Osage River valley segment alignment along the figure 4 south edge. Further note the very shallow through valley (defined by one contour line on each side) linking the north-northwest oriented Herbrandt Branch valley with south-oriented tributary valleys draining to the north-northwest oriented Osage River valley segment (as barbed tributaries). The valley alignments, very shallow through valley, and the barbed Osage River tributaries also provide evidence of a former southeast-oriented flood flow route which was beheaded and reversed by headward erosion of the deep Osage River valley, which then eroded the north-northwest-oriented Osage River valley segment. A close look at the drainage divide reveals other shallow through valleys linking north- and northwest oriented Moreau River tributary valleys with south-southeast-oriented Osage River tributary valleys.

Missouri River-North Moreau Creek drainage divide area

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

 

  • Figure 5 illustrates the Missouri River-North Moreau Creek drainage divide area located north and west of figure 3 and there is a small overlap area between the figure 5 southeast corner area and the figure 3 northwest corner area. The Missouri River flows in a southeast direction across the figure 5 northeast quadrant. Little Moniteau Creek is the east, northeast, north, east, and northeast oriented stream in the figure 5 northwest corner area and north of figure 5 flows in a north direction to join northeast-oriented Moniteau Creek, which enters the southeast-oriented Missouri River valley as a barbed tributary. Centertown is the town located slightly north and west of the figure 5 center. Rock Creek originates near Centertown and flows in a north, northeast, and east direction to the southeast-oriented Missouri River. East of Rock Creek is Meadows Creek, which is another barbed tributary flowing to the Missouri River. Grays Creek originates east of Centertown and flows in an east direction to join the Missouri River just east of the figure 5 east center edge. North Moreau Creek meanders in an east direction from the figure 5 southwest corner to south of the town of St Martins where it turns to meander in a south-southeast direction to the figure 5 south edge (east of center) and then to join east-northeast oriented South Moreau Creek to form the Moreau River. Note how North Moreau Creek has southeast-oriented tributaries from the north. For example, west of St Martins is southeast and south-southeast oriented Bennie Branch and south of Centertown is south-southeast oriented Strobel Branch. Note how these south-southeast oriented tributaries and their tributaries are aligned with north-northwest oriented streams. In the case of south-southeast oriented Strobel Branch its headwaters are linked with north-oriented Rock Creek headwaters and also with north-northwest oriented tributaries to Little Moniteau Creek. The figure 5 contour interval is 20 meters and does not provide enough detail to show shallow through valleys. However, based on valley alignments the North Moreau Creek valley eroded headward across the figure 5 region first with north-oriented valley segments being eroded headward along north ends of reversed flood flow routes. South-southeast oriented tributary valleys eroded headward along captured south-oriented flood flow routes until headward erosion of the deep Missouri River valley triggered flood flow reversals that eroded the north-oriented Moniteau Creek, Little Moniteau Creek, and tributary valleys.

Detailed map of Grays Creek-North Moreau Creek drainage divide area

Figure 6: Detailed map of Grays Creek-North Moreau 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 Grays Creek-North Moreau Creek drainage divide area seen in less detail in figure 5. Centertown is the town located in the figure 5 northwest corner. Binder Lake is the reservoir located along the figure 6 east center edge and drains in a northeast direction to east-southeast and east-northeast oriented Grays Creek seen in the figure 6 northeast quadrant. St Martins is the town located west of Binder Reservoir. North Moreau Creek meanders along the figure 6 south margin from the figure 6 west edge (south half) to a point south of St Martins where it turns to flow to the figure 6 south edge. Note how North Moreau Creek has several prominent southeast and south-oriented valley segments which are aligned with south and south-southeast oriented tributaries. Strobel Branch is the south-southest oriented tributary south of Centertown. Bennie Branch is the labeled south-southeast oriented tributary just west of St Martins. North-oriented drainage just north of Centertown flows to north oriented Rock Creek and northeast oriented Meadow Creek headwaters flow to the figure 6 north edge just west of the center. The figure 6 map contour interval is 20 feet and again note how the drainage divide between the north, northeast, and east oriented Missouri River tributaries and the south-oriented North Moreau Creek tributaries is crossed by shallow through valleys. For example, in section 3 (where St Martins is located) there are two areas along the drainage divide where elevations drop to between 760 and 780 feet. In the section 34 southwest corner to the northwest elevations rise to more than 820 feet and in the west half of section 2 to the southeast elevations rise to more than 820 feet. In other words the drainage divide elevations provide evidence of what was once a south-oriented flood flow channel to the actively eroding North Moreau Creek valley, which had been eroded into a topographic surface at least equivalent in elevation to the 820 foot plus high elevations seen today. The channel was at least 40 feet deep, probably deeper, and was beheaded by headward erosion of the Grays Creek valley. Elevations along the drainage divide gradually rise toward the northwest toward Centertown, although additional shallow through valleys can also be seen (some are defined by a single contour line on each side). The through valleys provide evidence of south-oriented flood flow prior to headward erosion of east-oriented Grays Creek valley and of the deep Missouri River valley, which beheaded and reversed flood flow on north ends of the beheaded flood flow routes west of the Grays Creek headwaters.

North Moreau Creek-South Moreau Creek drainage divide area

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

 

  • Figure 7 illustrates the North Moreau Creek-South Moreau Creek drainage divide area located south of the figure 5 map area and includes overlap areas with figure 5. Russelville is the town near the figure 7 center North Moreau Creek flows in an east-southeast direction from the figure 7 northwest corner and then meanders in an east direction across the figure 7 north center region before turning to meander in a south-southeast direction to join South Moreau Creek near the figure 7 east center edge. South Moreau Creek meanders in an east-northeast direction from the figure 7 south edge (near the county line in west half) to join North Moreau Creek and to form the Moreau River. Note how South Moreau Creek has south and southeast-oriented tributaries from the north. These tributaries include Rock Enon Creek, Morgan Branch, Roark Branch, Russellville Branch, and Millbrook Branch. Many North Moreau Creek tributaries from the south are oriented in northeast directions although in the Russellville area the tributaries are oriented in northwest directions. Note how some of the northeast oriented North Moreau Creek tributaries are aligned with northeast or southwest oriented North Moreau Creek valley segments. For example in the figure 7 northwest quadrant north-northeast oriented Cliifty Branch is aligned with a northeast oriented North Moreau Creek valley segment and in the figure 7 northeast quadrant north-northeast oriented Strobel Branch is aligned with a southwest-oriented North Moreau Creek valley segment. Also note how an unnamed north-northwest oriented tributary flowing from Russellville is aligned with a south-southeast oriented North Moreau Creek valley segment. These and other alignments provide evidence the North Moreau Creek valley eroded headward along segments of what were earlier south-oriented flood flow channels (or segments of what were evolving northeast-oriented channels moving captured south-oriented flood water to newly reversed flood flow routes further to the east). North and northwest oriented valleys were eroded by reversals of flood flow on north ends of beheaded flow routes, northeast-oriented valleys were usually eroded by captured flood flow moving to newly reversed flood flow routes, south- and southeast-oriented valleys were eroded along south and southeast oriented flood flow routes, and southwest-oriented valleys were eroded by reversals of flood flow on southwest ends of beheaded northeast-oriented flood flow routes which had been created by captured flood waters.

Detailed map of Van Pool Branch-Roark Branch drainage divide area

Figure 8: Detailed map of Van Pool Branch-Roark Branch drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

  • Figure 8 illustrates a detailed topographic map of the Van Pool Branch-Roark Branch drainage divide area seen in less detail in figure 7 above. Russellville is the town east of the figure 8 center. The Russellville Branch originates just east of Russellville and flows in a southeast direction to the figure 8 east edge (south half). Roark Branch originates just south and west of Russellville and flows in a south-southeast direction to the figure 8 south edge (east half). Morgan Branch flows in an east-southeast direction across the figure 8 southwest corner region. South of the figure 8 map area Morgan Branch, Roark Branch, and Russellville Branch all flow to South Moreau Creek. North-northeast oriented Cliffty Branch flows across the figure 8 northwest corner region. Van Pool Branch is the north-northeast stream located east of Cliffty Branch. Cliffty Branch and Van Pool Branch flow to North Moreau Creek, which is north of the figure 8 map area. The south end of a North Moreau Creek meander can just barely be seen along the figure 8 north center edge and is joined by an unnamed north-northwest oriented tributary, which originates near Russellville. Note also how Van Pool Branch has northwest-oriented tributaries. The map contour interval for the eastern three-fourths of the map is 20 feet, although the western fourth uses a 10 foot contour interval. In section 1 near the figure 8 west center edge elevations along the North Moreau Creek-South Moreau Creek drainage divide rise to more than 930 feet. In the northeast quadrant of section 35 in the figure 8 northeast quadrant elevations rise to more than 920 feet. Between those high points on the drainage divide elevations are always 20 or more feet lower with elevations dropping below 860 feet for a short distance in the section 5 northeast quadrant. The lower elevations provide evidence of what was a broad south-oriented flood flow channel prior to headward erosion of the North Moreau Creek valley. Flood waters were captured by headward erosion of the South Moreau Creek valley (south of figure 8) and the southeast-oriented tributary valleys eroded headward from that newly eroded valley. Next headward erosion of the North Moreau Creek valley (north of the figure 8 map area) captured the south-oriented flood flow and the north-oriented North Moreau Creek tributary valleys were eroded by reversals of flood flow on the north end of the beheaded flood flow channel. Remember the North Moreau Creek valley eroded headward from east to west and beheaded and reversed the flood flow in channel also in an east to west direction, meaning flood flow was reversed and flowing north in the east while further west in the broad channel flood flow may still have been flowing in a south direction.

South Moreau Creek-Osage River drainage divide area

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

 

  • Figure 9 illustrates the South Moreau Creek-Osage River drainage divide area located south and slightly west of the figure 7 map area and includes overlap areas with figure 7. Eldon is the larger town located in the figure 9 southwest corner. Eugene is the town located on the Miller-Cole County line in the figure 9 south center area. Osage River meanders can be seen in the figure 9 southeast corner region and the Osage River is flowing in a northeast direction, which means the meanders first show the river flowing in a northwest direction, then in a southeast direction, next in a northwest direction, and finally in a north-northeast direction. These meanders can be explained in the context of headward erosion of the deep Osage River valley along and across south and southeast oriented flood flow routes. Southeast-oriented valley segments were eroded headward along southeast oriented flood flow channels while the north-northeast and northwest oriented valley segments were eroded headward along reversed flood flow routes, with the flood flow reversals being caused by the beheading of south-oriented flood flow channels. Note how many Osage River tributaries from the north and west are oriented in southeast and south directions, including to the north-northeast Osage River valley segment. These tributary valleys were eroded headward along southeast- and south-oriented flood flow routes. North and northwest-oriented tributary valley segments were eroded by reversals of flood flow and northeast-oriented valley segments were probably eroded across flood flow routes. The South Moreau River originates west of Eldon (and the figure 9 map area) and crosses into the figure 9 at the figure 9 west center edge and then flows along the Moniteau-Miller County line until it is joined by north-northeast oriented Blythes Creek near the Miller-Moniteau-Cole County corner. South Moreau Creek then flows in a north-northeast direction along the Moniteau-Cole County line to near Enon where it turns to begin a series of large meanders across the figure 9 northeast quadrant. Note how South Moreau Creek has north-oriented tributaries, which generally originate on or near the South Moreau Creek-Osage River drainage divide, which is closely followed by highway 54. Note how the Osage River drainage basin has been more deeply eroded than the South Moreau Creek drainage basin. Osage River tributary valleys were eroded by south-oriented flood flow moving into the newly eroded Osage River valley. The drainage divide was created when headward erosion of the South Moreau Creek valley beheaded and reversed the south-oriented flood flow. As previously mentioned flood flow routes were beheaded and reversed in sequence, which meant newly reversed flood flow routes in the east captured yet to beheaded flood flow from further west. These captures of yet to be beheaded flood flow account for northeast-oriented South Moreau Creek tributary valley segments seen near the South Moreau Creek-Osage River drainage divide. For example, note how Clark Fork flows in a northeast direction along the drainage divide from near Spring Garden (north of Eugene) to near Brazito and then turns to flow in a northwest direction to join northeast-oriented South Moreau Creek.

Detailed map of Brush Creek-Jack Buster Creek drainage divide area

Figure 10: Detailed map of Brush Creek-Jack Buster 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 Brush Creek-Jack Buster Creek drainage divide area seen in less detail in figure 9 above. Eugene is the larger town located in the figure 10 southeast quadrant. Jack Buster Creek flows in a west-southwest direction from Eugene to the figure 10 south edge (west of center). South of the figure 10 map area Jack Buster Creek flows in a south direction to southeast-oriented Saline Creek, which then flows to the northeast-oriented Osage River. Etterville is the smaller town located in the figure 10 west center area. Note how Jack Buster Creek has south and southeast-oriented tributaries flowing from the Etterville region. North of Etterville in the figure 10 northwest corner is Brush Creek, which flows in a northeast direction to the figure 10 north edge and then flows in a north direction to join a southeast-oriented South Moreau Creek meander segment. Spring Garden is the very small town located in the figure 10 northeast quadrant. West of Spring Garden are west-oriented headwaters of northwest-oriented Brush Creek tributaries. East of Spring Garden are north oriented headwaters of north, east, and northeast oriented Clark Fork, which north and east of the figure 10 map area turns to flow in a northwest direction to join northeast-oriented South Moreau Creek. The South Moreau Creek-Osage River drainage divide is easy to identify on the figure 10 map and is crossed by shallow through valleys. For example in section 27 east of Etterville there is a shallow through valley linking south-oriented Jack Buster Creek tributary valleys with north oriented Brush Creek tributary valleys. The map contour interval is 20 feet and in section 27 drainage divide elevations drop to between 860 and 880 feet. In section 28 south and west of Etterville drainage divide elevations rise to more than 920 feet while in the west half of 26 a hill along the drainage divide reaches an elevation of at least 960 feet. The section 27 through valley in other words is at least 40 feet deep and may have been deeper when originally eroded. Another through valley can be seen in the section 26 east half and the west edge of section 25. The drainage divide in this region drops to between 880 and 900 feet. Elevations in the western half of section 26 rise to at least 960 feet and in the southwest corner of section 19 elevations rise to more than 1020 feet. This second through valley is at least 60 feet deep and links a northwest-oriented Brush Creek tributary valley with a southwest-oriented Jack Buster Creek tributary valley. These through valleys provide evidence of former south-oriented flood flow channels, which were beheaded and reversed by South Moreau Creek valley headward erosion. Flood waters had been moving to what at that time were actively eroding south-oriented Osage River tributary valleys, such as the Jack Buster Creek valley and its tributary valleys.

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.

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