Frenchman River-International border region landform origins, southwest Saskatchewan, Canada

· Cypress Hills, Milk River, Saskatchewan
Authors

Abstract:

Topographic map interpretation methods are used in determine landform origins for the region between the Frenchman River and the United States border in southwest Saskatchewan. The Frenchman River originates along the south side of the southwest Saskatchewan Cypress Hills and flows in an east and southeast direction to the United States border and then to join the Milk River in Montana. West of the Frenchman River headwaters is the southeast, east, and south-oriented Battle Creek drainage basin, with the Battle Creek valley linked by a well-defined through valley with the Frenchman River headwaters valley suggesting headward erosion of the south-oriented Battle Creek valley captured the west end of the Frenchman River drainage system. Numerous north-south oriented through valleys cross the drainage divide between the Frenchman River valley and interior drainage basins and Milk River tributary valleys to the south and provide evidence of massive south-oriented flood flow at the time the Frenchman River and Battle Creek valleys eroded headward into the region. Flood waters were derived from a rapidly melting thick North American ice sheet and were flowing along the ice sheet’s southwest margin. The Cypress Hills upland surface may have been formed during an earlier melt water flood event when ice-marginal melt water floods were captured and diverted in an east and/or northeast direction to flow onto the decaying ice sheet surface where they joined massive southeast-oriented supra-glacial melt water rivers. Subsequent ice sheet melting then enabled the deep Missouri River-Milk River-Frenchman River valleys to erode headward from an ice-walled and bedrock-floored canyon to capture the immense ice-marginal floods, which also deeply eroded regions south of the Cypress Hills region, which may have been located along the ice sheet’s margin.

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 Frenchman River-international border region 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 the links 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 Frenchman River-international border region landform evidence in southwest Saskatchewan, Canada 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.

Frenchman River-international border location map

Figure 1: Frenchman River-international border location map from Atlas of Canada Toporama index map (select and click on maps to enlarge).
  • Figure 1 illustrates an Atlas of Canada Toporama website index map for topographic maps in southwest Saskatchewan, Canada. Numbers for the larger grid maps index hard copy 1:250,000 scale topographic maps while numbers in the more detailed grid index hard copy 1:50,000 scale topographic. Numbers in the more detailed grid are shown on the topographic map illustrations included in this essay and can be used to identify locations. The Canada-United States border is shown (but not labeled) near the figure 1 south edge. The Alberta-Saskatchewan border is also shown near the figure 1 west edge. The South Saskatchewan River flows in an east direction through maps 72L15 and 72L16 in Alberta (near figure 1 northwest corner) into Saskatchewan to map 72K15 where it turns to flow in a southeast direction to Lake Diefenbaker, which is a large reservoir flooding the South Saskatchewan River valley. From Lake Diefenbaker the South Saskatchewan River flows in a north-northwest and then northeast direction to the figure 1 north edge. The Frenchman River originates near Cypress Lake (shown, but not labeled on figure 1 near corner of maps 72F5, 72F6, 72F11, and 72F12) and flows in an east and east-southeast direction to the international border in map 72G3. South of the international border the Frenchman River joins the Milk River in Montana (south of figure 1). West of the Frenchman River headwaters is south-oriented Battle Creek, which flows south to the international border in map 72F3 and then flows in a south-southeast direction to join the east-oriented Milk River, which can be seen flowing across the figure 1 southwest corner region. The south-southwest oriented Battle Creek tributary originating in map 72F3 is Lyons Creek and the southeast and south-southeast oriented stream originating in map 72F1 is Whitewater Creek, which is another Milk River tributary. The Frenchman River-international border region investigated in this essay is located south of the Frenchman River and north of the international border. Essays describing regions south of the international border include the Whitewater Creek-Frenchman River drainage divide area essay, the Whitewater Creek-Milk River drainage divide area essay, the Woody Island Coulee-Milk River drainage divide area essay, and the Battle Creek-Savoy Creek drainage divide area essay. Milk River drainage divide area essays can be found by selecting Milk River under the sidebar category list.
  • Before looking at the topographic map examples illustrated in the figures below some information about what was happening in southwest Saskatchewan and adjacent Montana at the time the Frenchman River drainage basin was formed may be useful. The Frenchman River drainage basin was eroded during the final stages of massive melt water flood at the end of a rapid melt down of a thick North American ice sheet. At that time the decaying ice sheet’s southwest margin was located just north of the present day Frenchman River drainage basin and north and east of the ice sheet margin was a giant ice-walled and bedrock-floored canyon, which had detached the rapidly melting ice sheet’s southwest margin. The ice-walled and bedrock-floored canyon had been carved by immense supra glacial melt water river flowing across the ice sheet’s surface and today the northeast and east facing Missouri Escarpment in Saskatchewan, North Dakota, and South Dakota marks the location of the canyon’s southwest and west wall. The ice sheet had been located in a deep “hole” and as result ice-marginal melt water floods flowing along the ice sheet’s southwest margin were flowing on a surface higher than floor of the ice-walled and bedrock-floored canyon, which was eroding its valley into ice sheet’s floor. As a result east and northeast-oriented tributary valleys were able to erode headward from the ice-walled and bedrock-floored canyon across the ice sheet margin to capture the southeast-oriented ice-marginal melt water floods. The final such tributary valley of real significance eroded headward from the ice-walled and bedrock-floored canyon in the North Dakota northwest corner and across northeast Montana, where today (west of Poplar, Montana) it is used by the Missouri River. The Milk River valley subsequently captured ice-marginal flood flow and diverted flood waters to the newly eroded “Missouri” River valley and the Frenchman River valley eroded headward from the newly eroded Milk River valley to move flood waters more efficiently to the Milk River and Missouri River valleys. Subsequently a major breach through the ice sheet’s detached southwest margin in Saskatchewan enabled the deep South Saskatchewan River valley to erode headward from the ice-walled and bedrock-floored canyon to capture southeast-oriented melt water flood flow that had been moving to the newly eroded Frenchman River, Milk River, and other Milk River tributary valleys.
  • As already mentioned headward erosion of the Missouri River, Milk River, and Frenchman River valleys from the ice-walled and bedrock-floored canyon in northwest Dakota represented the final erosion stage during the ice sheet’s rapid melt down, however there were many preceding stages, evidence for most of which has been destroyed. The ice sheet had been located in deep “hole” formed by deep glacial erosion under the thick ice sheet and by crustal warping caused by the ice sheet’s great weight. Remember the ice sheet was comparable in thickness and extent to the present day Antarctic Ice Sheet and it significantly altered the entire North American continent, even regions it did not cover. The ice sheet formed on a topographic surface now preserved, if it is preserved at all, on the highest level Rock Mountain erosion surfaces. Those high level erosion surfaces were uplifted since the ice sheet was formed and probably were uplifted as the ice sheet was melting and massive melt water floods flowed across them. Rocky Mountain uplift, and uplift of Rocky Mountain outlier ranges, was probably caused by ice sheet caused crustal warping. Even with uplift of the mountain regions massive ice-marginal melt water floods deeply eroded the deep “hole’s” southwest wall to produce what is today the northeast oriented upper Missouri River drainage basin. Much of this erosion occurred as ice-marginal flood waters from higher elevation regions south and west of the ice sheet’s southwest margin moved in northeast directions to join giant supra glacial meltwater rivers flowing on the decaying ice sheet’s surface. In the Frenchman River drainage basin area northeast and/or east-oriented melt water river flowed from south and west of the ice sheet’s southwest margin onto the ice sheet surface to enter what was probably an ice-walled and ice-floored canyon located north and east of the Cypress Hills region (near the Frenchman River headwaters). As the ice sheet surface and the floor of the ice-walled and ice-floored canyon became lower the route of that northeast- and/or east-oriented melt water river migrated to the east and southeast of the Cypress Hills region and for a time crossed the Wood Mountain region north and east of where the Frenchman River crosses the international border. Next the meltwater river route migrated further south and east and crossed the Flaxville Plain in northeast Montana. Finally the melt water river, which by then was flowing to what had become an ice-walled and bedrock-floored canyon, had developed a route along what is a large northeast-oriented abandoned valley leading to the North Dakota northwest corner, which is the original Missouri River valley. The original Missouri River valley was subsequently abandoned when a shift of melt water flood flow directions from south to north triggered a return of glacial climates.

East end of Frenchman River-international border region

Figure 2: East end of Frenchman River-international border region from Toporama 1:300,000 scale map.
  • Figure 2 uses a 1:300,000 scale Toporama topographic map to illustrate the east end of the Frenchman River-international border region. The area with no data available is located in Montana south of the west-to east oriented international border. The Frenchman River is the stream flowing in an east direction in the west half of map 72F8 and then turning north and even northwest before flowing in roughly an east direction to enter map 72G5 and to flow in roughly a southeast direction across the map 72G5 southwest quadrant, the map 72G4 northeast quadrant, and the map 72G3 southwest quadrant to the international border (south and east of the figure 2 map area). South and east of the figure 2 map area the Frenchman River joins the Milk River in Montana. The stream flowing in a southeast direction across the map 72F1 northeast quadrant and the map 72G4 southwest quadrant is Whitewater Creek, which also flows to the Milk River. The stream south and west of Whitewater Creek in map 72F1 is Lonetree Creek, which is a Whitewater Creek tributary. Note how elevations change throughout the figure 2 map area. The Frenchman River valley floor in map 72G3 has an elevation of less than 780 meters while elevations of greater than 1000 meters can be seen along the southern margins of maps 72F9 and 72G12. Between those 1000 meter high elevations are through valleys linking south-oriented Frenchman River tributary valleys with north-oriented drainage routes (which are discussed in the Wood River-Frenchman River drainage divide area essay). The 1000 meter plus elevation areas may be remnants of a high level erosion surface eroded by melt water floods flowing onto the ice sheet surface, although the through valleys were probably eroded by south-oriented melt water floods moving to the actively eroding and much deeper Frenchman River valley. The north-oriented drainage routes to north-oriented Wood River were eroded by reversals of flood flow as ice sheet melting lowered the ice sheet surface and opened up new drainage routes to the north. Note how shallow through valleys cross the Frenchman River-Whitewater Creek drainage divide indicating that south-oriented meltwater flood water moved to what was then the actively eroding Whitewater Creek valley prior to headward erosion of the Frenchman River valley (the shallow through valleys are much better seen on more detailed topographic maps seen below). Frenchman River headward erosion beheaded flood flow to the Whitewater River valley.

Frenchman River-Whitewater Creek east drainage divide area

Figure 3: Frenchman River-Whitewater Creek east drainage divide area from Toporama 1:150,000 scale map.
  • Figure 3 uses a 1:150,000 scale Toporama topographic map to illustrate the eastern Frenchman River-Whitewater Creek drainage divide area seen in less detail in figure 2 above. The Frenchman River flows in roughly a southeast direction through Huff Lake and Newton Lake in map 72G5 to Val Marie and then in a south direction along the south half of the figure 3 east edge. Whitewater Creek is labeled and flows in a southeast direction across the figure 3 southwest quadrant. Note the erosional remnant in map 72G4 northwest of Masefield which rises to more than 940 meters. Also note elevations greater than 940 meters in map 72F8. Between those 940 meter elevations is a through valley with a floor elevation of less than 880 meters linking the Frenchman River valley with the Whitewater Creek valley. The through valley was eroded by south-oriented flood flow moving to the Whitewater Creek valley prior to Frenchman River valley headward erosion. Frenchman River headward erosion beheaded the south-oriented flood flow and flood waters on the north end of the beheaded flood flow route reversed flow direction to erode a north-oriented Frenchman River tributary valley. The north-oriented Frenchman River tributary is a barbed tributary because it flows to a south-oriented oriented river. Another interesting through valley is used by the railroad east of Masefield. Note near the figure 3 southeast corner a hill rising to more than 880 meters. Between that hill and the hill rising to more than 940 meters northwest of Masefield is a through valley with a floor elevation of between 820 and 840 meters. The through valley links the Frenchman River valley with the valley of what is today and internal drainage basin. However south of the internal drainage basin is a through valley leading to an East Whitewater Creek tributary valley indicating that once flood waters flowed south along this somewhat deeper flood flow channel. Again headward erosion of the deep Frenchman River valley beheaded this south-oriented flood flow channel. The present day internal drainage basin may have been created by flood water scouring, deposition, and/or subsequent earth movements which blocked the south-oriented valley.

Frenchman River-Whitewater Creek west drainage divide area

Figure 4: Frenchman River-Whitewater Creek west drainage divide area from Toporama 1:150,000 scale map.
  • Figure 4 uses a 1:150,000 scale Toporama topographic map to illustrate the west drainage divide area between the Frenchman River and Whitewater Creek. The Frenchman River is labeled and flows in a southeast, east, northeast, northwest, southeast, northeast, south, northeast, and southeast direction across the figure 4 north half. Whitewater Creek is also labeled and flows in a southeast direction across the map 72F1 northeast quadrant. West of Whitewater Creek is southeast-oriented Lonetree Creek, which is not labeled and which is a Whitewater Creek tributary. No deep through valleys can be seen crossing the Frenchman Creek-Whitewater Creek drainage divide in this region although a shallow through valley can be seen south of the map number 72F8. The north-oriented Frenchman River tributary valley draining the north end of that through valley was eroded by a reversal of flood flow on the north end of a beheaded south oriented flood flow route. The flood flow channel had been moving flood water to what was at that time an actively eroding Whitewater Creek tributary valley. Headward erosion of the much deeper Frenchman River valley captured the flood flow and beheaded and reversed the south-oriented flood flow channel. As can be seen in figure 4 elevations decrease to the east, which means south- and southeast-oriented flood water was moving on higher elevation surfaces west of the deeper through valleys seen in figure 3. This situation existed all along the Frenchman River valley route (and also throughout the Missouri River drainage basin), with the Frenchman River valley eroding headward into the higher elevation regions to capture the immense flood flow still flowing on those upland surfaces. The presence of massive ice-marginal flood flows on those upland surfaces means at that time there were no deep river valleys to the north and west of the present day Frenchman River drainage basin. At that time the South Saskatchewan River valley and its tributary valleys had not yet been eroded and ice marginal flood waters were free to move across ice marginal bedrock surfaces (now largely removed) to reach the actively eroding Frenchman River valley.

Middle section Frenchman River-international border region

Figure 5: Middle section Frenchman River-international border region from Toporama 1:300,000 scale map.
  • Figure 5 uses a 1:300,000 scale Toporama topographic map to illustrate the middle section of the Frenchman River-international border region. Streams in figure 5 are not labeled and the Frenchman River flows in an east direction roughly along the border of maps 72F11 and 72F6 and then 72F10 and 72F7 to Eastend before turning to flow in a southeast direction across the map 72F7 northeast quadrant and to map 72F8 where it turns to flow in an east and northeast direction (with a jog to the northwest) to reach the figure 5 east center edge. Headwaters of southeast-oriented Whitewater Creek and its tributaries can be seen in map 72F1. The southwest-oriented drainage system in map 72F3 flowing to the Montana border near the figure 5 west edge is Lyons Creek, which in Montana joins south-southeast oriented Battle Creek, which like the Frenchman River and Whitewater Creek is a Milk River tributary. Drainage basins in the region near the corner of maps 72F2, 72F3, 72F6, and 72F7 are internal drainage basins and today normally do not have outlets, although they are linked to the Lyons Creek and Whitewater Creek drainage basins by well-defined through valleys seen on figure 5. Note a well-defined north-south oriented through valley south of Eastend in map 72F7 linking a north-oriented Frenchman River tributary valley with these local internal drainage networks (Border Creek as seen in figure 6). This through valley, which will be seen in more detail in figure 6, provides evidence of a major south-oriented melt water flood flow channel which was beheaded and reversed by Frenchman River valley headward erosion. Flood waters were probably flowing to what was at that time the actively eroding Whitewater Creek valley although some of the flood water also flowed to what was at that time the actively eroding Lyons Creek valley. The internal drainage basins seen today may have been created by deeper flood water scour of those regions, uneven deposition of flood transported sediments, and/or subsequent earth movements which blocked the flood eroded drainage routes. The north-oriented Frenchman River tributary valley was eroded by a reversal of flood flow on the north end of the beheaded south-oriented flood flow route.

Frenchman River-Border Creek drainage divide area

Figure 6: Frenchman River-Border Creek drainage divide area from Toporama !:150,000 scale map.
  • Figure 6 uses a 1:150,000 scale Toporama topographic map of the Frenchman River-Border Creek drainage divide area seen in less detail in figure 5 above. The Frenchman River is labeled and flows in a southeast direction across the map 72F7 northeast quadrant. Labeled north-oriented Frenchman River tributaries include Galliene Coulee, Outlaw Coulee, and Eastbrook Coulee. South-oriented labeled drainage systems in the figure 6 southeast quadrant include Wrightville Coulee and Frontier Coulee, which do not normally connect with any external drainage system, but which are linked by a through valley with the Whitewater Creek drainage basin. South-oriented labeled drainage routes in the figure 6 southwest quadrant include Border Creek and its tributary Claydon Coulee. Border Creek today does not normally drain to an external drainage system, but should overflow it would flow to Lyons Creek, with the water eventually reaching Battle Creek. Note locations of high elevations on figure 6. The highest elevation in the east is just south of the Frenchman River near the east edge of map 72F7 and exceeds 1000 meters. Elevations exceeding 1000 meters are found throughout the figure 6 northwest quadrant and west center region with some elevations exceeding 1120 meters near the northwest corner of map 72F7. Between the 1000 meter plus elevation in the east and the much higher elevations in the west is a broad through valley linking the north–oriented Eastbrook Coulee valley with the south-oriented Wrightville Coulee valley. The through valley floor elevation is between 920 and 940 meters meaning the through valley is at least 60 meters deep and probably was much deeper when initially eroded. The through valley was eroded as a south-oriented flood flow channel prior to headward erosion of the deep Frenchman River valley. Frenchman River valley headward erosion captured 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 Eastbrook Coulee valley. Other less obvious and narrower through valleys link north-oriented Frenchman River tributary valleys with south-oriented Border Creek drainage routes further to west and can be seen somewhat better on more detailed topographic maps, although none of the valleys are very deep.

Frenchman River-Lyons Creek drainage divide area

Figure 7: Frenchman River-Lyons Creek drainage divide area from Toporama 1:300,000 scale map.
  • Figure 7 uses a Toporama 1:300,000 scale topographic map to illustrate the Frenchman River-Lyons Creek drainage divide area west of the figure 5 map area and includes overlap areas with figure 5. The Frenchman River originates at Cypress Lake in the northwest corner of map 72F6 and flows in roughly an east direction to Eastend where it turns to flow in a southeast direction to the figure 7 east center edge. Note Cypress Lake is formed by a dam with water draining to the east to the Frenchman River and water also draining to the west to south-oriented Battle Creek, which flows in a south-southeast and southwest direction across the end of map 72F5 and then in southeast across the map 72F4 northeast corner and into map 72F3 where it turns to flow in a south direction to the Montana border. Note how Battle Creek has a north and west-northwest oriented tributary system in southwest quadrant of map 72F6. The southwest-oriented drainage system in the east half of map 72F3 is the Lyons Creek drainage system which eventually drains to Battle Creek in Montana. Note how multiple through valleys link the east-oriented Frenchman River valley with south-oriented tributaries to the west-northwest oriented Battle Creek tributary in map 72F6. The railroad uses one of the through valleys, another through valley is north of Robsart. Still another through valley is just to west and yet another through valley links the Lake Cypress basin with the Battle Creek valley along the line between maps 72F5 and 72F6. The through valleys were eroded by multiple south-oriented flood flow channels prior to headward erosion of the Frenchman River valley. Also note how the Battle Creek valley west of Cypress Lake is oriented in an east direction and appears to be a westward extension of the Frenchman River valley. Headward erosion of the deeper south-oriented Battle Creek valley probably captured the west end of what was then the newly eroded Frenchman River valley at a time when massive south-oriented flood flow was moving across the Cypress Hills upland surface north of the figure 7 map area. The greatest flow was moving south in a deep through valley eroded between the east and west Cypress Hills upland surface areas, which is located north of the south-oriented Battle Creek valley segment in map 72F12. Higher elevations north of the Frenchman River and of the east-oriented Battle Creek valley segment were probably protected with erosion resistant materials, which probably were not present (at least in the same quantity) in the Frenchman River valley area or other regions to the south. However at the time the Frenchman River valley began to erode headward into the figure 7 map area south-oriented flood waters were probably deeply eroding the figure 7 map area, which previously had been at an elevation equal to or close to the level of the present day Cypress Hills upland surface elevation. This high level erosion surface which preceded Frenchman River valley headward erosion had probably been formed by east- and/or northeast-oriented ice-marginal melt water floods flowing onto the decaying ice sheet surface to reach a deep ice-walled and bedrock-floored canyon which had been carved into the ice sheet surface, and which was located north and east of the Cypress Hills region.

Palisade Creek-Border Creek drainage divide area

Figure 8: Palisade Creek-Border Creek drainage divide area from Toporama 1:150,000 scale map.
  • Figure 8 uses a 1:150,000 scale Toporama topographic map to illustrate the Palisade Creek-Border Creek drainage divide area seen in less detail in figure 7 above. The Frenchman River is the east-oriented stream near the north margin of map 72F6 flowing to Ravenscrag and Neighbour and then across the map 72F11 southeast corner to the figure 8 north edge. Palisade Creek is an interesting stream south of the town of Palisade, which is linked by a well-defined through valley with a north-oriented Frenchman River tributary. Note how Palisade Creek flows in west direction toward the town of Palisade and then in a southwest direction until it ends. Continuing to the southwest are headwaters of a southwest-oriented Battle Creek tributary suggesting that at times Palisade Creek may drain to the Battle Creek. A south-oriented Palisade Creek tributary north of the town of Palisade drains the south end of the through valley linking the Palisade Creek drainage basin with the Frenchman River drainage basin. Also an interesting Palisade Creek tributary flowing through the town of Olga has south-oriented headwaters then flows in a west and north direction to reach Palisade Creek. Note how that tributary and the Palisade Creek headwaters drain an upland region where elevations rise above 1100 meters. Also note in the figure 8 southwest corner Old Man On His Back Plateau where elevations rise to more than 1060 meters. Between those two high areas is a broad southeast-oriented through valley linking the Palisade Creek drainage basin with the Border Creek drainage basin seen in the figure 8 southeast quadrant. The through valley floor elevation is between 960 and 980 meters meaning the valley is at least 80 meters deep and was probably deeper when initially eroded. The through valley provides evidence of a major southeast-oriented flood flow channel, which probably moved flood water to what was then the actively eroding Whitewater Creek valley. Subsequently headward erosion of the deeper Battle Creek-Lyons Creek valley captured flood waters south and west of the figure 8 map area (south of Old Man On His Back Plateau) to the Lyons Creek valleys diverting flood flow to the southwest. Later Battle Creek valley headward erosion diverted flood flow south and west along a route north of Old Man On His Back Plateau in the through valley located there. Next Frenchman River valley headward erosion captured the flood flow and diverted it east and southeast. And finally Battle Creek valley headward erosion beheaded the Frenchman River valley and diverted the flood flow from the areas west and north of Cypress Lake in a south direction toward the newly eroded and deep Milk River valley (in Montana).

Frenchman River-Battle Creek drainage divide area

Figure 9: Frenchman River-Battle Creek drainage divide area from Toporama 1:150,000 scale map.
  • Figure 9 uses a Toporama 1:150,000 scale topographic map to illustrate Frenchman River-Battle Creek drainage divide area seen in less detail in figure 7 above. The Frenchman River is labeled and originates in Cypress Lake and flows in east direction near the north edge of map 72F6. Battle Creek is labeled and flows in an east-northeast direction almost to Cypress Lake and then turns flow in a generally south direction to the figure 9 south edge. Note the well-defined north-south oriented through valleys linking the Frenchman River valley with south-oriented Battle Creek tributaries. One of the through valleys is located south of Cypress Lake and has a floor elevation of between 980 and 1000 meters. Just downstream from the Cypress Lake dam is another through valley with a similar valley floor elevation, although it is bounded on both sides by uplands rising to more than 1040 meters. A third through valley with a deeper valley floor (between 960 and 980 meters) is found near the figure 9 east edge and is also bounded by uplands rising to more than 1040 meters. Battle Creek itself flows south through a similar valley with a valley floor elevation of between 960 and 980 meters and with uplands on either side rising to more than 1000 meters. West of Battle Creek still another north-south oriented through valley near the town of West Plains links the east-oriented Battle Creek valley with a south-oriented Battle Creek tributary valley. These through valleys provide evidence of multiple south-oriented flood flow routes which were beheaded by headward erosion of the east-oriented Frenchman River valley with headward erosion of the slightly deeper south-oriented Battle Creek valley subsequently capturing the east-oriented Frenchman River west end. The multiple south-oriented flood flow channels suggest an anastomosing channel complex was eroding the south margin of the Cypress Hills upland surface as the Frenchman River valley eroded headward across the region to capture the south-oriented flood flow. Figure 10 below shows the region north of the Frenchman River and Battle Creek valleys to illustrate the Cypress Hill upland surface which the south-oriented flood water must have crossed.

Battle Creek-Frenchman River drainage divide area

Figure 10: Battle Creek-Frenchman River drainage divide area from Toporama 1:300,000 scale map
  • Figure 10 uses a 1:300,000 scale Toporama topographic map to provide a big picture view of the Battle Creek-Frenchman River drainage divide area along the south margin of the Cypress Hills upland surface. Battle Creek flows in a southeast and south direction from map 72E9 across the southwest quadrant of map 72F12 into map 72F5 where it turns to flow in an east-northeast direction to the northeast corner of map 72F5 and then just before reaching the Cypress Lake area turns to flow in a south direction to eventually reach the figure 10 south edge. Note how Battle Creek is flowing from the north side of the western Cypress Hills upland surface in a deep valley across the upland surface and then flows along the south side of the upland surface. This deep water gap across the Cypress Hills upland surface could only be formed at a time when melt water floods from north and west of the Cypress Hills upland surface were flowing at an elevation at least as high as the upland surface elevation. The deep through valley in map 72F12 between the west and east Cypress Hills upland surface regions was also eroded by south-oriented melt water flood flow and another shallower through valley near the west margin of map 72F11 was also eroded by south-oriented flood flow. Initially flood waters flowed south across on a surface at least as high as the Cypress Hill upland surface high elevations today. It is possible the region north of the Cypress Hills upland regions was filled with ice at the time flood waters flowed across the upland surface and eroded these north-south oriented valleys, although it is also possible reversals of flood flow deeply eroded a high level bedrock surface north of Cypress Hills region as deep valleys north of the figure 10 map area (e.g. South Saskatchewan River valley) beheaded and reversed south-oriented flood flow routes. In either case the Cypress Hills upland surface provides a marker of what was once the elevation of the bedrock surface south and west on the ice sheet’s southwest margin. This was the level of the regional bedrock surface into which the deep Missouri River-Milk River-Frenchman River valley initially eroded. South and southeast-oriented ice-marginal flood waters flowing into these newly eroded deep valleys and their tributary valleys lowered the regional surface in most areas leaving only a few erosional remnants such as those seen in figure 10.

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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