South Saskatchewan River-Frenchman River drainage divide area landform origins, southwest Saskatchewan, Canada

Authors

Abstract:

Topographic map interpretation methods are used to determine landform origins in the South Saskatchewan River-Frenchman River drainage divide area of southwest Saskatchewan. The South Saskatchewan River originates in southern Alberta and flows in a generally northeast direction with water eventually reaching Hudson Bay. The Frenchman River originates along the south margin of the Cypress Hills upland surface in southwest Saskatchewan and flows in an east and southeast direction to reach the Milk River in Montana, with water eventually reaching the Missouri and Mississippi Rivers and the Gulf of Mexico. The Cypress Hills upland region forms the west end of the South Saskatchewan River-Frenchman River drainage divide area and the Wood Mountain upland region is located just east of the study region east end. Between these two upland regions is the north-oriented Swift Current Creek valley, which drains to the South Saskatchewan River. East and west of the Swift Current Creek drainage basin are interior drainage basins in the regions between the South Saskatchewan River and the Wood Mountain and Cypress Hills uplands. Large north-south oriented through valleys cross the South Saskatchewan River-Frenchman River drainage divide, with the largest through valley linking the north-oriented Swift Current Creek valley with the Frenchman River valley. These large through valleys, an asymmetric drainage divide north of the Cypress Hills upland, and barbed tributaries provide evidence the drainage divide was crossed by massive south oriented floods at a time when regions north of the Cypress Hills and Wood Mountain upland surfaces was at least as high as those upland surfaces are today. Flood waters were probably ice-marginal melt water floods from a rapidly melting North American ice sheet and it is possible the higher elevations north of the upland surfaces were on the decaying ice sheet surface. Headward erosion of the deep South Saskatchewan River valley beheaded the south- and southeast-oriented flood flow with flood waters on north ends of beheaded flood flow routes reversing flow direction to erode north oriented South Saskatchewan tributary valleys (e.g. the Swift Current Creek valley).

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 South Saskatchewan River-Frenchman River drainage divide area landform origins in southwest 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 comment here with a link to those essays.
  • 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 South Saskatchewan River-Frenchman River drainage divide area landform evidence in southwest Saskatchewan will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm (see paradigm related essay in menu at top of page). This essay is included in the Missouri River drainage basin landform origins research project essay collection.

South Saskatchewan River-Frenchman River drainage divide area location map

Figure 1: South Saskatchewan River-Frenchman River drainage divide area location map from Atlas of Canada Toporama website index map (select and click on maps to enlarge).
  • Figure 1 illustrates a location map for the South Saskatchewan River-Frenchman River drainage divide area in southwest Saskatchewan and is an index map from the Atlas of Canada Toporama website. Numbers defining areas in the large grid identify hard copy 1:250,000 scale topographic maps and numbers in the more detailed grid identify hard copy 1:50,000 scale topographic maps. Large grid maps 72K, 72F, 72J, and 72G are located in southwest Saskatchewan with Montana (in the United States) being located to the south and Alberta being located to the west. The South Saskatchewan River is labeled in (large grid) map 72K and flows in a northeast direction in Alberta before entering Saskatchewan. Once in Saskatchewan the South Saskatchewan River flows in an east and southeast direction before turning to flow in a northeast, north-northwest, and northeast direction and eventually the water reaches Hudson Bay. The Frenchman River originates at Cypress Lake (shown, but not labeled near corner of small grid maps 72F5, 72F6, 72F11, and 72F12) and flows in an east and southeast direction to the international border in map 72G3 and south of the figure 1 map area joins the Milk River, with water eventually reaching the Gulf of Mexico. The South Saskatchewan River-Frenchman River drainage divide discussed in this essay is also the north-south continental divide. Note the lack of major South Saskatchewan River tributaries from the south. The one exception is Swift Current Creek, which originates in the northeast quadrant of large grid map 72F and then flows in a northeast and north-northwest direction to join the South Saskatchewan River in large grid map 72J. Most other drainage routes shown between the South Saskatchewan River and the Frenchman River end up in interior drainage basins with no modern-day outlet, although through valleys seen on the topographic maps provide evidence of former drainage routes. The South Saskatchewan River-Frenchman River drainage divide area investigated in this knol is located in large grid maps 72F and 72K. The Frenchman River-international border region landform origins essay discusses regions south of the Frenchman River and north of the United States border. Milk River drainage divide essays are listed under Milk River on the sidebar category list.
  • The Frenchman River originates on the south side of the Cypress Hills upland region straddling the Saskatchewan-Alberta border, which consists of two or more areas capped by a high erosion and/or deposition surface and north-south oriented through valleys link the east oriented Frenchman River valley with drainage basins to the north. North and east of where the Frenchman River enters the United States is the Wood Mountain upland region, which is capped by another, although somewhat lower erosion and/or deposition surface. Between the Cypress Hills upland region and the Wood Mountain upland region a broad north-south oriented through valley links the Frenchman River valley with the northeast-oriented Swift Current Creek valley, which originates remarkably close to the Frenchman River valley. East of Swift Current Creek is northeast-oriented Notukeu Creek, which flows to the north-oriented Wood River, which in turn flows to Old Wives Lake. Old Wives Lake today has no outlet, although through valleys link it with the south-oriented Big Muddy Creek valley, which drains to the Missouri River in northeast Montana. The Cypress Hills and Wood Mountain upland surfaces are unusually high regions surrounded by lower plains in all directions and their origin is important to understanding South Saskatchewan River-Frenchman River drainage divide area landform origins. The South Saskatchewan River and Frenchman River valleys eroded headward across the figure 1 map area very late during the melt down history of a thick North American ice sheet, which had been located in a deep “hole.” The ice sheet had originally formed on a topographic surface now preserved, if it is preserved at all, as the highest level Rocky Mountain erosion surfaces, although those high level Rocky Mountain erosion surfaces have probably been significantly uplifted since that time. The deep “hole” in which the ice sheet was located was created by deep glacial erosion and by crustal warping caused by the ice sheet’s great weight. Crustal warping continued as the ice sheet melted and massive ice marginal meltwater floods flowed across the high level Rocky Mountain erosion surfaces as the Rocky Mountains and various Rocky Mountain outlier ranges were uplifted. Generally the meltwater floods flowed in south and/or southeast directions, although in time the ice sheet surface melted to a point where it was lower than the surrounding bedrock surface. At that point the ice-marginal meltwater floods began to flow in east and northeast directions to move onto the ice sheet surface and to join giant supra-glacial melt water rivers.
  • The Cypress Hills erosion and/or deposition surface was probably formed as immense melt water rivers flowed in an east and/or northeast direction to a giant southeast-oriented ice-walled and bedrock-floored canyon carved by a supra-glacial melt water river into the decaying ice sheet surface. That giant canyon extended diagonally across southern Saskatchewan and North Dakota and then in a south direction across eastern South Dakota and in time became an ice-walled and bedrock-floored canyon and detached the ice sheet’s southwest margin. The northeast and east facing Missouri Escarpment in Saskatchewan, North Dakota, and South Dakota is today what remains of that giant canyon’s southwest and west wall. The east and/or northeast oriented melt water river flowing from south and west of the ice sheet’s southwest margin onto the ice sheet’s surface migrated in an east and southeast direction as the ice sheet’s surface was lowered. This migration in a downstream direction along the southeast-oriented ice-walled canyon is recorded by elevations of the Cypress Hills upland surface, the Wood Mountain upland surface, the Flaxville upland (in northeast Montana), and the elevation of a large abandoned northeast-oriented valley in the Medicine Lake region of northeast Montana. That large abandoned (Medicine Lake area) valley was eroded headward from the ice-walled and bedrock-floored canyon in the North Dakota northwest corner region and west of Poplar, Montana is today used by the Missouri River. The Milk River valley eroded headward from that deep valley and the Frenchman River valley subsequently eroded headward from the newly eroded Milk River valley. Headward erosion of these deep valleys from the ice-walled and bedrock-floored canyon represented the last major erosion events during the ice sheet’s rapid melt down and also some of the final events in eroding the deep “hole’s” southwest wall, which is today the upper Missouri River drainage basin. The ice sheet’s rapid melt down ended when melt water floods were diverted from flowing in a south direction to the Gulf of Mexico to flowing across the ice sheet floor to the North Atlantic and other northern oceans. This change in meltwater flood flow direction changed ocean currents and also triggered a major climatic change, which resulted in a freezing of the north-oriented melt water floods and establishment of a new thin ice sheet.

Notukeu Creek-Frenchman River drainage divide area

Figure 2: Notukeu Creek-Frenchman River drainage divide area from Toporama 1:300,000 scale topographic map.
  • Figure 2 uses a Toporama 1:300,000 scale topographic map to illustrate the Notukeu Creek-Frenchman River drainage divide area just west of the Wood Mountain upland surface region. Streams in figure 2 are not labeled, however the Frenchman River flows in an east and southeast direction from map 72F7 to map 72F8 and then to map 72G5 and finally to map 72G4 and the figure 2 south edge. Notukeu Creek originates in the map 72F9 southwest quadrant and flows in a north-northeast direction to the north edge of map 72F9 and then turns to flow in an east direction to the figure 2 east edge (the railroad roughly parallels Notukeu Creek from near Shaunavan to the figure 2 east edge). East and north of the figure 2 map area Notukeu Creek flows to the north-oriented Wood River, which in turn flows to the Old Wives Lake interior basin. Note how the Frenchman River has a well-developed and extensive south oriented tributary network especially in map 72G5 and how Notukeu Creek has a system of north- and northeast-oriented tributaries in maps 72F9 and 72G12. Follow the Notukeu Creek-Frenchman River drainage and note elevations. Beginning in the map 72F9 southwest quadrant there are high elevations in excess of 1020 meters and then elevations drop to less than 960 before rising to more than 1000 meters. The low area near the map 72F9 south center edge is a through valley linking a north-oriented Notukeu Creek tributary valley with a south-oriented Frenchman River tributary valley. Continuing along the drainage divide in an east direction just east of the map 72G12 southwest corner is another low area where elevations drop to less than 920 meters. Continuing along the drainage divide in an east and southeast direction to map 72G6 elevations rise again to more than 1000 meters. The low area east of the map 72G12 southwest corner is another through valley linking a north-oriented Notukeu Creek tributary valley with a south-oriented Frenchman River tributary valley. This second through valley is at least 80 meters deep and in much broader than the first through valley. The through valleys are evidence of south-oriented flood flow channels which were carved into a high level erosion and/or deposition surface which was at least as high as high points on the present day Notukeu Creek-Frenchman River drainage divide.The south-oriented flood waters were deeply eroding the landscape south of the present day drainage divide and were captured by headward erosion of the Frenchman River valley. Headward erosion of the east-oriented Notukeu Creek valley (from reversed flood flow on the present day Wood River alignment perhaps as headward erosion of the deep South Saskatchewan River valley captured the south- and southeast-oriented flood flow further to the north) beheaded and reversed the south-oriented flood flow to erode the north-oriented Notukeu Creek tributary valleys. Reversals of flood flow occurred on north ends of beheaded flood flow routes.

Detailed map of Wise Creek-Denniel Creek drainage divide area

Figure 3: Detailed map of Wise Creek-Denniel Creek drainage divide area from Toporama 1:150,000 scale topographic map.
  • Figure 3 uses a 1:150,000 scale topographic map to illustrate the Wise Creek-Denniel Creek drainage divide area seen in less detail in figure 2 above. The Frenchman River is labeled and flows from the figure 3 west edge (south half) across map 72F8 and map 72G5 to Hoff Lake before reaching the figure 3 south edge  (just west of center). Denniel Creek is a labeled south-southeast oriented Frenchman River in map 72G5 and joins the Frenchman River south of the figure 3 map area. Wise Creek is a northwest and north-northeast oriented stream in the map 72G12 southwest corner region and flows to northeast-oriented Bull Creek, which is a Notukeu Creek tributary. Note the well-defined through valley linking the north-oriented Wise Creek valley with the south-southeast oriented Denniel Creek valley. The through valley floor elevation is between 900 and 920 meters. Follow the drainage divide eastward to near the figure 3 east edge and note how there is a high area where elevations rise to more than 1000 meters. Also follow the drainage divide westward from the through valley and note how elevations of high areas also exceed 1000 meters. This through valley was seen in less detail in figure 2 and is much better illustrated in figure 3. The through valley is at least 80 meters deep and is a major topographic feature. The valley was eroded as a south-oriented flood flow channel, which just before being beheaded and reversed was delivering flood waters to what was then the actively eroding Denniel Creek valley. Headward erosion of the deep east and northeast-oriented Notukeu Creek-Bull Creek valley north of the through valley captured the south-oriented flood flow channel and diverted the flood waters north and east to what was then a newly reversed flood flow channel on the present day Wood River alignment. Flood waters flowing to the actively eroding Denniel Creek valley were beheaded and flood flow on the northwest end of the beheaded flood flow channel reversed flow direction to erode the northwest-oriented Wise Creek valley segment. Note how the northwest-oriented Wise Creek valley segment is on approximately the same alignment as southeast-oriented Bull Creek tributaries seen in map 72F9.

Detailed map of Notukeu Creek-Gunn Creek drainage divide area

Figure 4: Detailed map of Notukeu Creek-Gunn Creek drainage divide area from Toporama 1:150,000 scale topographic map.
  • Figure 4 uses a Toporama 1:150,000 scale topographic map to illustrate the Notukeu Creek-Gunn Creek drainage divide area seen in less detail in figure 2 above. The Frenchman River is not labeled but flows in a north direction from the figure 4 south edge (west half) into map 72F8 and then “meanders” in an east and east-southeast direction to the figure 4 south edge (east half) in map 72G5. Mule Creek is south-oriented Frenchman River tributary near the figure 4 west edge and Gunn Creek is a south-oriented Mule Creek tributary flowing from the map 72F9 south center area to join Mule Creek (just before Mule Creek joins the Frenchman River). Notukeu Creek is labeled and is flowing in a generally east direction in the figure 4 north half. An unlabeled northeast oriented Notukeu Creek tributary is located north of the south-oriented Gunn Creek headwaters. Note how the northeast-oriented Notukeu Creek tributary valley is linked by a well-defined through valley with the south-oriented Gunn Creek valley. The through valley floor elevation is generally in the 960-980 meters range although at one point it appears to be lower than 960 meters. Elevations along the drainage divide on either side of the through valley rise to more than 1000 meters, suggesting the through valley is at least 40 meters deep. The location of this higher elevation through valley relative to the Wise Creek-Denniel Creek through valley seen in figure 3 and in the figure 4 southeast quadrant is shown. Between the two identified  through valleys is a third through valley linking the north-oriented Bull Creek valley with the south-oriented Rattlesnake Creek valley. This Bull Creek-Rattlesnake Creek through valley also has a floor elevation of between 960 and 980 meters with upland surfaces on either side rising to more than 1000 meters. These three adjacent through valleys provide evidence of what was probably a south-oriented anastomosing channel complex moving south-oriented flood waters to what was at one time the actively eroding Frenchman River valley. At that time the Notukeu Creek valley had not yet been eroded and flood waters were flowing across a high level surface north of the present Notukeu Creek-Frenchman River drainage divide. That high-level surface was at least as high as the present day Notukeu Creek-Frenchman River drainage divide and flood waters were eroding deep channels into it. It is possible the surface was underlain with ice, although it is also possible the surface had been formed on the underlying bedrock. Headward erosion of the deep Notukeu Creek valley beheaded the south-oriented flood flow channels and flood waters on north ends of the beheaded flood flow channels reversed flow direction to erode the north-oriented Notukeu Creek tributary valleys. Because flood flow channels were beheaded one at a time from east to west south-oriented flood flow from west of the newly beheaded and reversed flood flow channels could be captured by the newly reversed flood flow channels and moved in northeast and east directions eroding northeast- and east-oriented valleys and also eroding the north-facing slope (north of the drainage divide).

Swift Current Creek-Frenchman River drainage divide area

Figure 5: Swift Current Creek-Frenchman River drainage divide area from Toporama 1:300,000 scale topographic map.
  • Figure 5 uses a Toporama 1:300,000 scale topographic map to illustrate the Swift Current Creek-Frenchman River drainage divide area. The Frenchman River flows in an east direction from the figure 5 west edge (south half) to Eastend (near south edge of map 72F10) and then turns to flow in a southeast direction to the figure 5 south center edge. South and east of the figure 5 map area the Frenchman River eventually reaches the Milk River with water eventually flowing to the Gulf of Mexico. Swift Current Creek originates in map 72F10 north and east of Eastend and flows in a north-northeast and north direction to and across the southeast corner of map 72F15 and then into map 72F16  before entering Reid Lake (the reservoir seen in the figure 5 northeast corner). North and east of the figure 5 map area Swift Current Creek eventually reaches the South Saskatchewan River, with water eventually reaching Hudson Bay. The Swift Current Creek-Frenchman River drainage divide seen in map 72F10 is the north-south continental divide. Note how a well-defined through valley links the north-oriented Swift Current Creek valley with the southeast and east oriented Frenchman River valley. Elevations on the through valley floor range between 940 and 960 meters while elevations on the Cypress Hills upland surface to the northwest rise to more than 1120 meters and elevations in the southwest corner of map 72F9 rise to more than 1020 meters. The through valley is at least 60 meters deep and the lower elevations to the east suggest much deeper erosion of the drainage divide in that direction. The through valley provides evidence of a major south-oriented flood flow channel, which moved large quantities of melt water to what was at one time the actively eroding Frenchman River valley. Headward erosion of the deep South Saskatchewan River valley (well north of the figure 5 map area) beheaded the south-oriented flood flow and flood waters on the north end of the beheaded flood flow channel reversed flow direction to erode the north-oriented Swift Current Creek valley (actually north-oriented Swift Current Creek valley segments were beheaded and reversed by headward erosion of east-oriented Swift Current Creek valley segments, which is a somewhat more complicated history). Southeast-oriented and barbed Swift Current Creek tributaries provide further evidence of the flood flow reversal that eroded the north-oriented Swift Current Creek valley.

Detailed map of Swift Current Creek-Frenchman River drainage divide area

Figure 6: Detailed map of Swift Current Creek-Frenchman River drainage divide area from Toporama 1:150,000 scale topographic map.
  • Figure 6 uses a 1:150,000 scale Toporama topographic map to provide a more detailed look at the Swift Current Creek-Frenchman River drainage divide area seen in figure 5 above. The Frenchman River flows in a southeast direction from Eastend (along figure 6 west edge, south half) to the figure 6 south edge (west half). Swift Current Creek originates on the Cypress Hills upland surface north of Anxiety Butte and flows in a south direction before entering the large through valley and making a U-turn to flow in a north-northeast direction to the figure 6 north edge (just east of center). Note how in addition to its south-oriented headwaters Swift Current Creek also has other south-oriented tributaries and in particular Jones Creek. These south-oriented tributaries provide evidence of south-oriented flood flow routes which once flowed to what was then the actively eroding Frenchman River valley. Prior to headward erosion of the Frenchman River valley the south-oriented flood flow continued in a south direction probably to what was then the actively eroding Milk River valley. Rock Creek is a north-oriented Swift Current Creek tributary located east of Swift Current Creek. Note how the north-oriented Rock Creek headwaters are aligned with south-oriented Frenchman River tributaries. North-northeast oriented Notukeu Creek headwaters are also seen in the figure 6 east center edge area, but are not labeled (Grassy Creek flows to Notukeu Creek). Figure 6 also shows elevations better than figure 5 and note the 1020 meter high elevations in the figure 6 southeast corner region. Also note elevations greater than 1120 meters on the Cypress Hills upland surface where Swift Current Creek begins. Between the high elevations is the broad through valley linking the north-oriented Swift Current Creek valley with the southeast and east-oriented Frenchman River valley. As seen in figure 5 through valley floor elevations are between 940 and 960 meters indicating the through valley is at least 60 meters deep (based on the eastern upland elevation). The through valley was eroded by south-oriented flood flow, but the south-oriented flood flow was beheaded and reversed to erode the north-oriented Swift Current Creek valley. The relatively short south-oriented Frenchman River tributaries draining the through valley south end suggest the south-oriented flood flow was moving in a low gradient flood flow channel, which was beheaded by headward erosion of a much deeper flood flow channel north of the figure 6 map area. Melting of ice sheet remnants just north of the drainage divide area may have caused this somewhat unusual flood flow reversal.

Detailed map of Bridge Creek-Swift Current Creek drainage divide area

Figure 7: Detailed map of Bridge Creek-Swift CurrentCreek drainage divide area from Toporama 1:150,000 scale topographic map.
  • Figure 7 uses a Toporama 1:150,000 scale topographic map to illustrate Bridge Creek-Swift Current Creek drainage divide area seen in less detail in the figure 5 map area above. Swift Current Creek is not labeled in figure 7, but flows in a north-northeast direction from the northeast corner of map 72F10 across the southeast corner of map 72F15 into map 72F16 and then to the figure 7 east edge (north half). Bone Creek originates near Black Hole Lake (near south edge of map 72F15) and flows in a north, east, and south direction to join north-northeast oriented Swift Current Creek. Jones Creek flows in a south direction from the Black Hole Lake area to the figure 7 south center edge and as seen in figure 6 eventually joins north-oriented Swift Current Creek south of the figure 7 map area. North-oriented Rock Creek flows from the northwest corner of map 72F9 to join Swift Current Creek in map 72F16. Bridge Creek originates as a northwest-oriented stream and then after flowing down the Cypress Hills northwest facing slope turns to flow in a northeast direction along the base of the west-northwest facing Cypress Hills slope. Note how Bridge Creek is shown as a discontinuous drainage route. North of the figure 7 map area Bridge Creek turns to flow in a north direction and then ends in a lake with no modern-day outlet (although should it overflow the flow would end up in the South Saskatchewan River). Note how in map 72F15 a northwest-oriented Bridge Creek tributary is linked by a well-defined through valley with the east and south-oriented Bone Creek valley segment. The through valley has been eroded into the Cypress Hills upland surface and has a valley floor elevation of between 880 and 900 meters. The Cypress Hills upland surface on either side of the through valley rises to more than 1020 meters (even more to west) indicating the through valley is at least 120 meters deep. Note also elevations of 820-840 meters where the northwest-oriented tributary joins northeast-oriented Bridge Creek indicating the region north and west of the Cypress Hills upland is significantly lower than the through valley floor. The through valley was eroded by southeast-oriented melt water flood flow first moving to the Milk River drainage system in the south (including via the actively eroding Frenchman River valley). Reversal of the south-oriented flood flow in the east half of the figure 7 map area then eroded the north-northeast oriented Swift Current Creek valley while southeast-oriented flood flow still moved across the Cypress Hills upland region, which means the area north and west of the Cypress Hills upland was at least as high as the upland is today. Some or all of the high elevation may have been due to the presence of ice, although some of the elevation may have been due to bedrock which was removed by ice-marginal flood flow which was subsequently reversed to flow along the Cypress Hills base and then in a north direction to the actively eroding South Saskatchewan River valley.

Maple Creek-Frenchman River drainage divide area

Figure 8: Maple Creek-Frenchman River drainage divide area from Toporama 1:300,000 scale topographic map.
  • Figure 8 uses a 1:300,000 scale Toporama topographic map to illustrate the Maple Creek-Frenchman River drainage divide area in the Cypress Hills region. The Frenchman River originates at Cypress Lake (shown, but not labeled near the corner of maps 72F5, 72F6, 72F11, and 72F12) and flows in an east direction to Eastend (near south edge of map 72F10) before turning to flow in a southeast direction near the figure 8 southeast corner. Note how Cypress Lake is linked by a through valley with an east-northeast and south-southeast oriented stream in map 72F5 (that stream is Battle Creek). The Frenchman River valley in map 72F6 is located along the south margin of the eastern Cypress Hills upland region, which is drained by south-oriented Frenchman River tributaries. The much steeper north-facing slope of the Cypress Hills upland is drained by north-oriented streams, which today end up in shallow interior basins, but which if they should overflow to a major drainage route would flow to the South Saskatchewan River. Maple Creek is one of the north-oriented streams flowing near the town of Maple Creek (near line between maps 72F14 and 72F13). The asymmetric drainage divide suggests south-oriented flood flow moved across the Cypress Hills upland to what was at that time the actively eroding Frenchman River valley. At that time the region north of the Cypress Hills upland was at least as high as the upland region is today. That height may have been achieved by the presence of ice, which could mean the north-facing slope represents where the decaying ice sheet southwest margin was located at that time. Large melt water rivers eroded deeper valleys across the Cypress Hills upland, two of which are easily recognized in figure 8. The deepest valley is located in map 72F12 and represents the Gap between the East and West Cypress Hills upland regions. The floor of the Gap has an elevation of between 1080 and 1100 meters while elevations to the east rise to at least 1260 meters and to the west elevations rise even higher. In other words the Gap through valley is at least 160 meters deep. A somewhat shallower through valley is located near the west margin of map 72F11 and has a floor elevation of between 1140 and 1160 meters. Elevations to the east rise to more 1220 meters and to west rise to more than 1260 meters, meaning the through valley is at least 60 meters deep. These through valleys were eroded by south-oriented melt water flood flow at a time when the surface north of the Cypress Hills upland was being lowered (either by melting of ice and/or by deep erosion of bedrock). The north-facing slope was created by the melting of ice present there and/or by erosion of bedrock by southeast and east oriented ice-marginal flood waters, which had been captured by reversed flood flow routes to the actively eroding South Saskatchewan River valley.

Detailed map of Maple Creek-Frenchman River drainage divide area

Figure 9: Detailed map of Maple Creek-Frenchman River drainage divide area from Toporama 1:150,000 scale topographic map.
  • Figure 9 uses a 1:150,000 scale Toporama topographic map to illustrate the Maple Creek-Frenchman River drainage divide area seen in less detail in figure 8 above. The Frenchman River originates at Cypress Lake (near map 72F5 northeast corner and map 72F6 northwest corner) and flows in an east direction south of the figure 9 map area. Cypress Lake is formed by a dam, which has raised the water level to the point where it can also drain in a west direction to south-oriented Battle Creek in the figure 9 southwest corner. Belanger Creek is a south-oriented Frenchman River tributary draining the through valley near the west margin of map 72F11. Note how Belanger Creek originates almost on the crest of the north-facing Cypress Hills slope and drains in a southwest direction to Jackpot Lake and then in a south direction along the south end of the through valley. North of the Belanger Creek headwaters are headwaters of north-oriented Maple Creek, while the through valley north end is drained by north-oriented Fleming Creek. Through valley floor elevations in the Jackpot Lake area are between 940 and 960 meters meaning the through valley is at least 60 meters deep. Note how other south-oriented Frenchman River tributaries originate on the Cypress Hills upland surface almost at the edge the north-facing Cypress Hills slope. For example just west of the fire tower in map 72F12 a south-southeast oriented Frenchman River tributary originates at an elevation of 1240 meters while just to the north Adams Creek headwaters flow in a north direction down the steep north-facing Cypress Hills slope. The south-southeast oriented Frenchman River tributary valley was eroded by south-southeast oriented ice-marginal flood flow moving to what at that time was the actively eroding Frenchman River valley. At that time the region north of the Cypress Hills was at least as high as the present 1240 meter high Cypress Hills upland surface today (and the deep through valleys on either side had yet to be eroded). Reversals of flood flow north of the Cypress Hills upland surface occurred in sequence from east to west meaning southeast-oriented ice-marginal flood flow could be captured by newly reversed flood flow further to the east. Such captures of flood flow produced east-oriented flood flow channels, which helped erode the north-facing Cypress Hills slope. Also, because the high level surface remained longer in the west than in the east the deep through valley along the figure 9 west edge was eroded after the Fleming Creek-Belanger Creek through valley was eroded.

Detailed map of Gap Creek-Frenchman River drainage divide area

Figure 10: Detailed map of Gap Creek-Frenchman River drainage divide area from Toporama 1:150,000 scale topographic map.
  • Figure 10 uses a 1:150,000 scale Toporama topographic map to illustrate the Gap Creek Frenchman River drainage divide area seen in less detail in figure 8 above. The Frenchman River originates at Cypress Lake (near figure 10 southeast corner) and flows in an east direction. Cypress Lake is a reservoir and the dam can be seen along the figure 10 south edge just west of the southeast corner. The lake level is high enough that drainage can also flow west and drainage routes west of Cypress Lake flow to south-oriented Battle Creek, which flows to the figure 10 south edge just west of Cypress Lake. South of the figure 10 map area Battle Creek eventually flows to the Milk River in Montana. Upstream from the Cypress Lake area Battle Creek flows in a south-southeast and south direction from the figure 10 west edge (north half) past Fort Walsh and then to the town of Battle Creek (near figure 10 southwest corner) before flowing south of the figure 10 map area. South of the figure 10 map area Battle Creek turns to flow in an east-northeast direction toward Cypress Lake before turning to flow in a south direction. Oxarat Creek is a south-oriented Battle Creek tributary draining the south end of the large north-south oriented through valley (the Gap) carved between the East and West Cypress Hills upland regions. Gap Creek drains the north end of the through valley in a north and east direction. The through valley floor elevation at the drainage divide is between 1080 and 1100 meters. Elevations east of the through valley rise to more than 1260 meters while west of the through valley elevations rise to more than 1340 meters. Note the unnamed Battle Creek tributary flowing in a south direction from Adams Lake and Coulee Lake parallel to the adjacent larger through valley. This unnamed Battle Creek tributary begins in two separate narrower through valleys providing evidence of multiple south-oriented flood flow channels. While not seen in figure 10 the Battle Creek valley begins on the north side of the West Cypress Hills upland surface and provides evidence of still an additional through valley crossing the high upland region. These multiple through valleys and the asymmetric drainage divide provide evidence of massive south-oriented melt water flood flow across the Cypress Hills upland region, which again is evidence the region north of the Cypress Hills was at that time higher than the Cypress Hills upland surface is today.

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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