Wood River-Poplar River drainage divide area landform origins, southern Saskatchewan, Canada

Authors

Abstract:

Topographic map interpretation methods are used to determine landform origins for the Wood River-Poplar River drainage divide in southern Saskatchewan. The Wood River is a north-oriented drainage route flowing to Old Wives Lake, which today has no outlet. The Poplar River is a south and southeast-oriented Missouri River tributary originating in southern Saskatchewan and joining the east and southeast oriented Missouri River in northeast Montana. East of the Poplar River is south and southeast-oriented Big Muddy Creek, which is linked by a large through valley with the Old Wives Lake basin to the north. The Wood River-Poplar River drainage divide area is today an upland region known as Wood Mountain, which stands approximately 300 meters higher than the deep through valley linking Old Wives Lake with Big Muddy Creek. Topographic map evidence in the form of through valleys eroded across the Wood Mountain upland surface provide evidence south oriented glacial melt water floods once flowed on a topographic surface at least as high as the present day Wood Mountain upland surface. It is possible significant thicknesses of bedrock material was removed from the region prior to south oriented flood flow events which crossed the Wood Mountain upland surface. Deep melt water flood erosion carved the south and southeast oriented Poplar River drainage basin to the south of the present day drainage divide while headward erosion of the deep Big Muddy Creek valley and tributary valleys along what is today the Wood Mountain north flank systematically beheaded and reversed the south-oriented flood flow channels. Newly beheaded and reversed flood flow channels captured yet to be beheaded flood flow from channels further to the west. Such captured flood water provided water volumes required to erode north-oriented valleys and also created flood flow movements that eroded the Wood Mountain north flank. The north-oriented Wood River valley was eroded by a reversal of flood flow which captured significant flood water from west of the study region.

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 Wood River-Poplar River drainage divide area landform origins in southern Saskatchewan, Canada. 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 Wood River-Poplar River drainage divide area landform evidence in southern Saskatchewan 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.

Wood River-Poplar River drainage divide area location map

Figure 1: Wood River-Poplar River drainage divide area location map (select and click on maps to enlarge). All maps used in this essay were downloaded from the Natural Resources Canada Toporama web site. The large grid identifies 1:250,000 topographic map sheets and the more detailed grid identifies 1:50,000 topographic map sheets. 

  • Figure 1 provides a Natural Resources Canada index map for a large region of southern Saskatchewan, with Montana in the United States being located south of the index map area. The index map identifies 1:250,000 and 1:50,000 topographic maps available from Natural Resources Canada and map numbers will be used to identify illustrated features in this essay. For example, Regina, the Saskatchewan capital, is located near the northeast corner of map 72I7 and is located on Wascana Creek, which flows in a northwest direction before turning to flow in a north direction to join the east-oriented Qu’Sppelle River (not labelled in figure 1). Many drainage routes in figure 1 and in other figures used in this essay are not labeled and I will try to identify key drainage routes as the essay proceeds. The South Saskatchewan River is the southeast oriented river flowing from map 72K15 to Stewart Valley in map 72J12 and then flowing in a northeast direction to Elbow in map 72O2. Note how the South Saskatchewan turns to flow in a northwest direction at Elbow. North of the figure 1 map area the South Saskatchewan River turns again to flow in a northeast direction to join the North Saskatchewan River with water eventually reaching Hudson Bay. The southeast oriented stream in Montana which flows from the figure 1 west edge (north of southwest corner) and which makes a northeast jog (where some lakes are located) and then which flows to the figure 1 south edge (west of center) is the Milk River. South of figure 1 the Milk River joins the east-oriented Missouri River, which is located south of the figure 1 map area. The Frenchman River is a major (labeled) Milk River tributary originating in southern Saskatchewan and flowing in a southeast and south direction to join the Milk River in Montana. The easternmost of the Frenchman River tributaries shown is Wetherall Creek (not labeled) and flows from map 72G2 to join the Frenchman River in Montana. Between Wetherall Creek and the Poplar River headwaters are south-oriented Rock Creek headwaters, with Rock Creek (unlabeled) also flowing to the Milk River in Montana. The southeast-oriented stream originating near the west edge of map 72G1 is the West Fork Poplar River and joins the Poplar River in Montana. The Poplar River originates in map 72G1 (east of West Poplar River) and flows in a southeast and south direction to join the Missouri River south of the figure 1 map area, The southeast- and south-oriented drainage route east of the Poplar River is Big Muddy Creek, which also joins the Missouri River south of the figure 1 map area. The Poplar River-Big Muddy Creek drainage divide area landform origins, northeast Montana essay discusses regions between the Poplar River and Big Muddy Creek south of the international border and is included under the MT Missouri River category on the sidebar category list.
  • Looking at Saskatchewan just north of the Poplar River and Big Muddy Creek headwaters note Old Wives Lake in maps 72J1 and 72I4. Old Wives Lake is located in an interior drainage basin and has no outlet, however a large south- and southeast-oriented through valley does extend from the Old Wives Lake basin across maps 72H13, 72H12, 72H5 (northeast corner), 72H6, and 72H3 (northeast corner) to south-oriented Big Muddy Creek in map 72H2. This valley is today filled by elongate lakes and discontinuous drainage routes. This valley origin is discussed in the South Saskatchewan River-Big Muddy Creek drainage divide area landform origins essay (see Saskatchewan in sidebar category list) and is a northern extension of the Big Muddy Creek valley. A major drainage route to the Old Wives Lake basin extends in a north-northeast direction from map 72G7 to map 72J1 and has east-southeast oriented headwaters in map 72G6. This drainage route is the Wood River and today drains a large interior basin in southern Saskatchewan. The lake near the north edge of map 72G8 is Twelve Mile Lake and today drains in a northwest direction to the Wood River. The region between the north-oriented Wood River drainage basin and the south-oriented Poplar River and West Fork Poplar River drainage basins (plus the Rock Creek and easternmost Frenchman River tributary drainage basins) is today an upland region known as Wood Mountain and is the Wood River-Poplar River drainage divide area addressed in this essay. Evidence presented in this essay suggests immense south-oriented melt water floods flowed across the present day Wood Mountain upland to what was at one time the actively eroding Poplar River valley and its tributary valleys. The north-northeast oriented Wood River valley was probably eroded by reversals of south-oriented flood flow, which was beheaded by headward erosion of what is now the large south-oriented through valley linking the Old Wives Lake basin with the Big Muddy Creek valley. The north-northeast oriented Wood River valley was eroded headward across southeast-oriented ice-marginal flood flow, which deeply eroded the region north of the Wood Mountain upland prior to being captured by Wood River valley headward erosion.
  • Before looking at the more detailed maps a big picture view of how some figure 1 drainage routes, other than in the Wood River-Poplar River drainage divide area, evolved might be useful. Note southeast-oriented Long Creek in map 72H9. Just west of Long Creek is the unlabeled southeast-oriented (with northwest-oriented headwaters near Yellow Grass) Souris River. Long Creek is a tributary to the southeast-oriented Souris River, which flows in a broad lowland between the northeast-facing Missouri Escarpment to the southwest and discontinuous upland regions to the northeast. Long Creek is flowing near the Missouri Escarpment base. North of the Long Creek and Souris River headwaters are headwaters of northwest-oriented Avonlea Creek, Moose Jaw River, and Wascana Creek, which in map 72I turn to flow in a northeast direction to join the east-oriented Qu’Appelle River. North and west of the northeast-oriented Moose Jaw River segment are southeast-oriented Thunder Creek and unlabeled southeast-oriented Qu’Appelle River headwaters. Avonlea Creek and Thunder Creek flow in opposite directions along the Missouri Escarpment base. Note also how Thunder Creek and the unlabeled southeast-oriented Qu’Appelle River headwaters originate almost at the edge of Lake Diefenbaker, which today floods the South Saskatchewan River valley. The Missouri Escarpment is what remains of the southwest wall of what was once a giant ice-walled and bedrock-floored canyon carved by an immense supra glacial melt water river into the surface of a rapidly decaying North American ice sheet. The giant ice-walled and bedrock-floored canyon for all practical purposes detached the ice sheet’s southwest margin, which was located south and west of the Missouri Escarpment. The detached ice sheet southwest margin served as barrier which prevented immense southeast-oriented ice marginal melt water floods from flowing into the giant southeast-oriented ice-walled and bedrock-floored canyon. While breaches in this massive ice wall did develop (e.g. the northeast-oriented South Saskatchewan River valley was eroded across such a breach) for the most part drainage events in the ice-walled canyon were different from drainage events along the detached ice sheet’s southwest margin’s southwest margin.
  • The huge melt water river flowing on the ice-walled and bedrock-floored canyon’s floor initially flowed in a southeast and south direction to the ice sheet margin in southeast South Dakota where it flowed to what was then the actively eroding Missouri River valley. Headward development of tributary ice-walled and bedrock-floored canyons then began to open up new drainage routes across the decaying ice sheet floor to what is now the Saint Lawrence drainage system and later to what is now Hudson Bay. These new drainage routes systematically captured the huge southeast and south-oriented melt water river, first in southeast North Dakota (see Sheyenne River U-turn) and second in north central North Dakota (see Souris River U-turn). Next headward erosion of the east-oriented Qu”Appelle River valley captured the immense southeast-oriented melt water river and flood waters on northwest ends of the beheaded flood flow routes reversed flow direction to erode the northwest-oriented Moose Jaw River, Avonlea Creek, and Wascana Creek valleys. Finally headward erosion of the northeast-oriented South Saskatchewan River valley (along a newly opened flood flow route to the Hudson Bay region) beheaded the southeast-oriented flood flow to the newly eroded Qu’Appelle River valley. These events account for drainage routes on the former ice-walled and bedrock-floored canyon floor. South and west of the Missouri Escarpment the detached ice sheet southwest margin served as barrier, which generally prevented ice marginal melt water floods from moving directly onto the deeper ice-walled canyon’s floor. Most present day landscape features in the region south and west of the detached ice barrier were eroded by immense southeast-oriented melt water floods, although a long history preceded the development of present day landscape features. The ice sheet had been located in a deep “hole” and the ice-walled and bedrock-floored canyon existed in the final ice sheet melting stages. Prior to that time the region surrounding the decaying ice sheet was gradually lowered by deep melt water flood erosion, and it is probable ice-marginal floods flowed from the surrounding region onto the decaying ice sheet surface. While evidence beyond what topographic maps show is needed to confirm this hypothesis, it should be remembered that there are no pre glacial surfaces located anywhere in the figure 1 map area.

Big picture topographic map for Wood River-Poplar River drainage divide area

Figure 2: Big picture topographic map for Wood River-Poplar River drainage divide area (downloaded from a 1:300,000 scale Toporama map). 
  • Figure 2 provides a big picture topographic map view of the Wood River-Poplar River drainage divide area. The Poplar River flows in a southeast direction across the map 72G1 northeast quadrant and the map 72H4 southwest quadrant to the figure 2 south edge. The West Poplar River flows in a south-southeast direction near the west margin of map 72G1. South-oriented drainage in map 72G2 flows to Rock Creek. The lake in the northwest quadrant of map 72H4 (east of Rock Glen) is Fife Lake and southeast oriented drainage flowing to the figure 2 east edge (just north of southeast corner) flows to the south oriented East Poplar River, which is located east of the figure 2 map area. The elongate lake near the north edge of map 72G8 is Twelve Mile Lake, which today drains in a north-northwest direction to the figure 2 north edge and then to the north-northeast oriented Wood River. Other northwest and north-northwest oriented drainage in maps 72G7 and 72G10 also flows to the north-northeast oriented Wood River. North of the figure 2 map area the Wood River flows to Old Wives Lake. The intermittent lake in map 72H12 is located in the large through valley connecting the Old Wives Lake basin with the south and southeast oriented Big Muddy Creek valley. Remember, there is no continuous drainage route in this through valley today, but when the valley was eroded it was eroded by south and southeast oriented melt water flood flow probably flowing along the southwest margin of the detached southwest margin of the rapidly decaying North American ice sheet. The region north of Twelve Mile Lake was deeply eroded by southeast and east oriented melt water floods flowing to the evolving and deep south- and southeast-oriented Big Muddy Creek valley. These southeast- and east-oriented melt water floods were captured by headward erosion of the north-northeast oriented Wood River valley. Flood waters on northwest ends of beheaded flood flow routes reversed flow direction to erode the northwest and north-northwest oriented Wood River tributary valleys. The present day Wood River-Poplar River drainage divide near the south edge of map 72G8 stands approximately 200 meters higher than most regions north of Twelve Mile Lake. As will be seen in the following figures south-oriented melt water floods cross the present day Wood River-Poplar River drainage divide, which means regions north of Twelve Mile Lake at that time were at least 200 meters higher than they are today. It is possible some or all of that elevation was the result of ice, which was present in the region at that time. But, whatever was located north of what is now Wood Mountain, the surface was at least as high as Wood Mountain is today. The flood flow reversals occurred in sequence from east to west, which meant flood waters in the west were still flowing on the high level topographic surface while north-facing Wood Mountain escarpment was being eroded in the east.

Twelve Mile Lake-Fife Lake drainage divide area

Figure 3: Twelve Mile Lake-Fife Lake drainage divide area from Toporama 1:150,000 scale map..
  • Figure 3 illustrates the Twelve Mile Lake-Fife Lake drainage divide area seen in less detail in figure 2 above. The eastern end of Twelve Mile Lake is seen in the figure 3 northwest corner area and as seen in figures 1 and 2 drains in a northwest direction to the north-northeast oriented Wood River, which flows to Old Wives Lake. The intermittent lake in the figure 3 northeast corner is Willow Bunch Lake, which is located in the through valley (with no continuous drainage today) linking the Old Wives Lake Basin with the south and southeast oriented Big Muddy Creek valley. Montaque Lake near the north edge of map 72H5 is in a closed basin today, although should it ever overflow it would spill eastward towards Willow Bunch Lake. The Fife Lake drainage route, when it drains, as discussed in figure 2 is to the south oriented East Poplar River seen along the south half of the figure 3 east edge. Note how the south oriented East Poplar River headwaters originate at an elevation of approximately 840 meters in Jean Louis Legare Regional Park area, just south of the northeast-facing escarpment, which formed as the southwest wall of what is today the deep Old Wives Lake-Big Muddy Creek through valley. Today the escarpment forms the northeast flank of the Wood Mountain upland region. West of the East Poplar River near the center of map 72H5 is a south oriented Fife Lake tributary originating near St Victor Petroglyphis Provincial Historic Park (east side). Note how that south oriented Fife Lake tributary is linked by a through valley with a north-oriented Montague Lake tributary. The through valley is defined by two 20-meter contour lines on each side. Further west in map 72H5 is the Twin Valley through valley linking a northwest-oriented Montague Lake tributary (which turns to flow along the escarpment base to Montague Lake) with the Fife Lake basin. The Twin Valley through valley floor elevation is between 820 and 840 meters and elevations to east and west rise to more than 900 meters. These through valleys provide evidence of south- and southeast-oriented melt water flood flow channels that once flowed across the Wood Mountain upland surface to what were then actively eroding East Poplar River tributary valleys. At that time the deep Old Wives Lake-Big Muddy Creek through valley had not been eroded and flood waters north of the Wood Mountain upland were flowing on a topographic surface at least as high as the figure 3 Wood Mountain upland surface today. Headward erosion of the deep Old Wives Lake-Big Muddy Creek through valley and its tributary valleys beheaded the south- and southeast-oriented flood flow channels in sequence from east to west and flood waters on north ends of beheaded flood flow channels reversed flow direction to erode the north-oriented Montague Lake and other tributary valleys.

Twelve Mile Lake-Fife Lake drainage divide area

Figure 4: Twelve Mile Lake-Fife Lake drainage divide area from Toporama 1:150,000 scale map.
  • Figure 4 illustrates the Twelve Mile Lake-Fife Lake drainage divide area west of the figure 3 map area and includes overlap areas with figure 3. Twelve Mile Lake is the elongate lake near the north edge of figure 4 and map 72G8. Fife Lake is located in the figure 4 southeast corner. Wood Coulee is a southeast-oriented drainage route in the map 72G8 southeast quadrant flowing to Fife Lake. Note how Wood Coulee is linked by a well-defined through valley with a northwest-oriented Twelve Mile Lake tributary (Gollier Creek). The through valley floor elevation appears to be between 840 and 860 meters. Elevations to the east rise to more than 900 meters and elevations to the west rise to more than 960 meters. This well-defined northwest-southeast oriented through valley was eroded as a southeast-oriented melt water flood flow channel at a time when the deep Twelve Mile Lake basin did not exist. At the time flood waters flowed in a southeast direction from north of the figure 4 map area to erode the southeast-oriented Wood Coulee valley on a topographic surface at least as high as the drainage divide. Note how southeast-oriented Wood Coulee tributaries originate on the 900 meter high surface east of the through valley. These southeast-oriented tributary routes were established by southeast-oriented flood flow routes moving across that 900 meter plus high surface, meaning flood waters at one time were flowing on a surface north of the present day Wood Mountain upland that was at least 900 meters high. Note how west of the through valley south-southeast oriented Gilford Creek, Lost Child Creek, and Solverson Creek originate on an even higher elevation surface (at least 940 meters high) and flow to an unlabeled southeast-oriented stream. The unlabeled southeast-oriented stream is the Poplar River, which also originates at an elevation greater than 940 meters. Note how southeast-oriented Poplar River headwaters are linked to the north-oriented Wood Mountain Creek valley, which drains to the west end of Twelve Mile Lake (and then to the Wood River). The origin of these southeast-oriented Poplar River headwaters on the high Wood Mountain drainage divide is further evidence southeast-oriented melt water flood flow moved across the entire Wood Mountain upland region and deeply eroded the surrounding region. The north-oriented Wood Mountain Creek valley was eroded by a reversal of flood flow as headward erosion of the deep Old Wives Lake-Big Muddy Creek through valley and its tributary valleys beheaded the southeast-oriented flood flow routes in sequence from east to west. Yet to be beheaded flood flow routes west of the Wood Mountain Creek valley provided the water volumes required to erode the north-oriented Wood Mountain Creek valley.

Detailed map of Gollier Creek-Fife Lake drainage divide area

Figure 5: Detailed map of Gollier Creek-Fife Lake drainage divide area from Toporama 1:40,000 scale map.
  • Figure 5 provides a more detailed map of the Gollier Creek-Fife Lake drainage divide area seen in less detail in figure 4 above. Gollier Creek flows in a northeast direction from the figure 5 west edge (north half) past the words “Old Post Coulee” and “Wood Coulee” and then turns to flow in a north-northwest direction to the figure 5 north edge (west half) and north of figure 5 flows to Twelve Mile Lake. As previously noted Twelve Mile Lake drains in a northwest direction to the north-northeast oriented Wood River, which flows to the Old Wives Lake closed basin. The southeast-oriented stream flowing from map number “72G8” to the figure 5 east edge (near southeast corner) is the stream identified as Wood Coulee in figure 4 and flows to Fife Lake. Also, as previously noted Fife Lake, when it does drain, drains to the East Poplar River with water eventually reaching the Missouri River. The northwest-southeast oriented through valley linking the north-northwest oriented Gollier Creek valley with the southeast-oriented Wood Coulee valley (draining to Fife Lake) is even more evident in this detailed map than in previous less detailed maps. The through valley floor has an elevation of between 830-840 meters and elevations greater than 940 meters can be found in the figure 5 northeast quadrant while elevations greater than 960 meters can be found in the figure 5 southwest quadrant. Note the presence of shallower and higher elevation through valleys at other points along the Old Wives Lake-Missouri River drainage divide. The figure 5 landform evidence is best explained in the context of massive southeast-oriented floods flowing across a topographic surface at least as high the highest figure 5 elevations today to actively eroding and deep southeast-oriented East Poplar River tributary valleys. Whether flood waters north of the figure 5 map area were flowing on a bedrock surface or on the ice-formed surface cannot be answered from figure 5 evidence, although the figure 5 evidence documents such a high level topographic surface did exist. The north-oriented valleys were eroded by flood flow reversals as headward erosion of deep valleys north of the Wood Mountain upland systematically beheaded the southeast-oriented flood flow routes. Whether the deep valleys were carved into a bedrock surface and/or an ice-covered surface is unknown.

Detailed map of drainage divide area near Layton Hills

Figure 6: Detailed map of drainage divide area near Layton Hills from Toporama 1:20,000 scale map.
  • Figure 6 illustrates a very detailed topographic map of the Twelve Mile Lake-Fife Lake drainage divide area and is located along the drainage divide just east of the figure 5 map area. North and northwest-oriented drainage routes west of Bald Butte flow to Twelve Mile Lake while the northeast-oriented stream located east of Bald Butte drains to Montague Lake. South and southeast oriented drainage routes flow to Fife Lake. Note how the drainage divide is crossed by several identifiable through valleys carved between what are today slightly higher areas. For example, just west of the Layton Hills is the south oriented headwaters valley of a south-southeast oriented Fife Lake tributary. The present day drainage divide, which is in the figure 6 north center area, has an elevation of between 870 and 880 meters. The south-oriented valley west of the Layton Hills has been eroded across a ridge with elevations greater than 910 meters (both to the east and to the west). These elevations suggest the through valley was at least 30 meters deep when eroded and probably was deeper. Near the figure 6 west edge a narrow and meandering through valley links north-oriented drainage routes with south-oriented drainage routes. The floor of this narrow through valley has an elevation of between 890 and 900 meters and elevations greater than 920 meters can be found on either side. Perhaps just as significant as the north-south oriented through valleys is a west to east oriented through valley in the figure 6 north center area linking northwest and north-northwest oriented Twelve Mile Lake tributaries with a northeast-oriented Montague Lake tributary. This west-east oriented through valley illustrates what happened as southeast and south-oriented flood flow routes were beheaded and reversed in sequence from east to west. Headward erosion of a deep east and/or southeast oriented valley north of the figure 6 beheaded south-oriented flood flow routes moving across the figure 6 east margin area while southeast- and south-oriented flood flow further to the west was still moving across the figure 6 map area. Reversed flood flow on the newly beheaded flood flow routes captured flood flow from the yet to be beheaded flood flow routes in the west and the captured flood flow eroded an east-oriented valley as it flowed to the actively eroding and much deeper northeast-oriented valley. In this case the west to east oriented through valley has a floor elevation of between 870 and 880 meters while elevations to the north and south rise to more than 900 meters.

Gollier Creek-Gilford Creek drainage divide area

Figure 7: Detailed map of South Branch Salt Creek-Lake Creek drainage divide area from Toporama 1:40,000 scale map.
  • Figure 7 illustrates the Gollier Creek-Gilford Creek drainage divide area west of the figure 5 map area and seen in less detail in figure 4. Gilford Creek, Lost Child Creek, and other southeast and south-southeast oriented streams flow to the southeast oriented Poplar River located south of the figure 7 map area. As previously noted the Poplar River flows to the Missouri River. Gollier Creek flows in a northeast direction to the figure 7 northeast corner where it turns to flow in a north-northwest direction to Twelve Mile Lake. Also as previously noted Twelve Mile Lake drains in a north-northwest direction to north-northeast oriented Wood River, which flows to the Old Wives Lake closed basin. Note the south-oriented Poplar River tributaries are usually linked to the north-oriented Gollier Creek tributary valleys by shallow through valleys. Elevations are higher than in the regions further east and the through valleys are only defined by a single 10-meter contour line on each side. However at least seven north-south shallow through valleys can be seen and provide evidence south-oriented flood flow once crossed the drainage divide. Note drainage divide elevations in the figure 7 map area are generally in the 970 meter range although some elevations exceed 980 meters. Also of interest in figure  7 is the drainage divide between northeast oriented Gollier Creek and the northeast oriented Gollier Creek tributary to the south of Gollier Creek, which is also crossed by through valleys. The northeast-oriented Gollier Creek tributary valley was eroded in advance of the Gollier Creek valley by flood flow captured from yet to be beheaded flood flow routes west of the newly beheaded and reversed north-northwest oriented Gollier Creek valley segment (which had been beheaded and reversed by headward erosion of a deep east-oriented valley north of the present day Wood Mountain upland). Headward erosion of the northeast-oriented Gollier Creek valley and its shorter northeast-oriented tributary valleys next beheaded southeast- and south-oriented flood flow routes to newly eroded northeast-oriented Gollier Creek tributary valley. This process was then repeated by headward erosion of the northeast-oriented valley north of the northeast-oriented Gollier Creek valley segment. Capture of yet to be beheaded flood flow from west of the newly beheaded and reversed flood flow routes not only provided water volumes required to erode significant north-oriented valleys, but also created new flood flow routes, which eroded northeast- and east-oriented valleys.

Wood Mountain Creek-Poplar River drainage divide area

Figure 8: Wood Mountain Creek-Poplar River drainage divide area from Toporama 1:150,000 map.
  • Figure 8 provides a big picture topographic map of the Wood Mountain Creek-Poplar River drainage divide area located west of the figure 4 map area and includes overlap areas with figure 4. The Poplar River is not labeled in figure 8, but is the unlabeled southeast-oriented stream between Horne Creek and Scaman Creek in map 72G1. Scaman Creek, Solverson Creek, Lost Child Creek, and Gilford Creek are all Poplar River tributaries. The West Poplar River originates along the boundary between maps 72G1 and 72G2 and flows in south direction to the figure 8 south center edge. South of the figure 8 map area the West Poplar River flows in a southeast direction to join the Poplar River, which then flows to the Missouri River. South-oriented streams west of the West Poplar River flow to Rock Creek, which flows to the Milk River, which in turn flows to the Missouri River. North-oriented drainage in maps 72G7 and 72G8 all flows to the north-northeast oriented Wood River, which flows to the Old Wives Lake closed basin. Note how elevations are slightly higher than seen in figure 7 with elevations reaching 1000 meters along the drainage divide near the figure 8 west edge. Shallow through valleys can be seen linking the north-oriented valleys with the south oriented valleys and are defined by one 20-meter contour line on each side. These multiple north-south oriented through valleys provide evidence of multiple south oriented flood flow channels such as might be found in a south-oriented anastomosing channel complex. Further, multiple shallow through valleys provide evidence flood waters once flowed across a topographic surface at least as high as the figure 8 drainage divide. Figure 8 drainage divide elevations are approximately 150 meters higher than drainage divide elevations seen in figure 3, which means the figure 3 drainage divide was much more deeply eroded than the figure 8 drainage divide. East of the figure 3 map area is the deeper through valley linking the Old Wives Lake basin with the south- and southeast-oriented Big Muddy Creek valley, which was eroded more than 100 meters deeper. The melt water flood erosion depth documented by these elevations is significant, although may only be a fraction of the depth of deep erosion that occurred. The Wood Mountain drainage divide represents the highest elevations found in the region today and there are no nearby markers to determine whether melt water floods crossed still higher level topographic surfaces. This interpretation of deep glacial and melt water flood erosion of the region is fundamentally different from previous interpretations, which usually interpret the Wood Mountain drainage divide to be a pre glacial topographic surface remnant.

Detailed map of Wood Mountain Creek-Poplar River drainage divide area

Figure 9: Detailed map of Wood Mountain Creek-Poplar River drainage divide area from Toporama 1:20,000 scale map.
  • Figure 9 provides a detailed topographic map of the Wood Mountain Creek-Poplar River drainage divide area seen in less detail in figure 8 above. North-oriented streams flowing to the figure 9 north are headwaters of north-oriented Wood Mountain Creek and water eventually reaches the Wood River and Old Wives Lake. The south-oriented Poplar River is labeled and south of the figure 9 map area turns to flow in a southeast direction to eventually reach the Missouri River. Scaman Creek (east of Poplar River) is a southeast-oriented Poplar River tributary. Horne Creek and the south-oriented stream west of Horne Creek are West Poplar River tributaries, with the West Poplar River flowing in a southeast direction to join the Poplar River. Reading figure 9 is somewhat confusing because the contour interval in map 72G8 is 10 meters while the contour interval in map 72G1 is 25 feet. Regardless of the different units and contour intervals shallow north-south oriented through valleys can be seen linking the south-oriented Poplar River valley with the north-oriented Wood Mountain Creek valley and also a south-southwest oriented West Poplar River tributary valley with a north-oriented Wood River tributary valley. The through valleys, while not deep, are well-defined valleys eroded across the drainage divide and provide evidence of at least two different south-oriented flood flow channels to what was once the actively eroding Poplar River valley system. While subtle, this figure 9 evidence documents glacial melt water floods that flowed across the Wood Mountain upland surface. As previously mentioned the figure 9 drainage divide elevations are at least 250 meters higher than the floor of the deep Big Muddy Creek valley to the east. Evidence for glacial melt water flood flow across the figure 9 drainage divide also is evidence that at one time elevations of regions north and east of the figure 9 map area were at least as high as the figure 9 drainage divide elevation today and is also evidence for removal of up to 250 meters of bedrock material from the region surrounding the high Wood Mountain drainage divide. Also as previously mentioned there are no higher regional elevations to use as markers to determine how much material was removed before the figure 9 drainage divide surface was formed. In the context of the “thick ice sheet that melted fast” paradigm deep glacial and melt water flood erosion of the North American surface may account for significantly deeper glacial and/or melt water flood erosion in the Wood Mountain upland region, although evidence from a much larger geographic region must be viewed to document such a suggestion.

Detailed map of Wood River-West Poplar River drainage divide area

Figure 10: Detailed topographic map of Wood River-West Poplar River drainage divide area from Toporama 1:40,000 scale map.
  • Figure 10 provides a detailed topographic map of the Wood River-West Poplar River drainage divide area west of the figure 9 map area and seen in less detail in figure 8 above. Again figure 10 is somewhat hard to read because elevations in maps 72G1 and 72G2 are shown using 25 foot contour lines while elevations in maps 72G8 and 72G7 are shown using 10 meter contour lines. The West Poplar River is labeled and West Poplar River tributaries in the northwest corner of map 72G1 can easily be identified. South of the figure 10 map area the West Poplar River turns to flow in a southeast direction to eventually reach the Poplar River and then the Missouri River. South-oriented drainage in map 72G2 not flowing to the West Poplar River flows to south-oriented Morgan Creek, which flows to Rock Creek, which in turn flows to the Milk River, which is a Missouri River tributary. Note how West Poplar River and Morgan Creek headwaters are intertwined, suggesting that at one time the shallow valleys were all components of the same south-oriented anastomosing channel complex. Headward erosion of the Southeast-oriented West Poplar River valley captured south-oriented flood flow to the west margin of map 72G1, but did not capture south-oriented flood flow routes further to west. The northeast-oriented drainage route flowing to the figure 10 east edge (near northeast corner) flows to Wood Mountain Creek and eventually to the Wood River and Old Wives Lake. The northwest oriented drainage route in the figure 10 northwest quadrant is Six Mile Creek, with water also eventually reaching the Wood River and Old Wives Lake. Like in previous figures shallow through valleys can be identified linking many of the north-oriented valleys with south-oriented valleys. Note also how northwest oriented Six Mile Creek headwaters are linked to southeast-oriented headwaters and tributaries of the northeast-oriented stream. In the figure 10 north center area a west to east oriented through valley can be identified linking the northwest- and northeast-oriented valleys. The through valley was eroded by yet to beheaded and reversed flood flow west of the newly beheaded and reversed flood flow route on the Wood Mountain Creek alignment. Flood waters flowed in a southeast direction into the figure 10 map area along what is now the northwest-oriented Six Mile Creek valley and then flowed in an east-southeast and northeast direction to the actively eroding and now north-oriented Wood Mountain Creek valley. Such captures of yet to be beheaded flood flow routes provided water volumes required to erode significant north-oriented valleys and also helped erode the Wood Mountain upland region northern flank.

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 produced and/or compiled by Natural Resources Canada and were downloaded from the Natural Resources Canada Toporama web site. Hard copy maps can be obtained from dealers offering Natural Resource Canada topographic maps or may be observed in libraries located throughout Canada and elsewhere.

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