Bison Creek-Boulder River drainage divide area landform origins, Jefferson County, Montana, USA

Authors


Abstract:

This essay uses topographic map evidence to interpret landform origins in the region between Bison Creek and the Boulder River in Jefferson County Montana. The Boulder River, which after flowing in a north direction, turns to flow in an east, southeast, and south-southwest direction to join the east oriented Jefferson River, which flows to the north oriented Missouri River with water eventually reaching the south oriented Mississippi River and the Gulf of Mexico. Bison Creek originates at Elk Park Pass, which crosses the east-west continental divide (near Butte, Montana) and flows to the east oriented Boulder River. The Little Boulder River is located east of Bison Creek and flows in a south and northeast direction to join the southeast oriented Boulder River. South of the Little Boulder River elbow of capture are headwaters of south and south-southeast oriented Whitetail Creek, which flows to the Jefferson River. Little Whitetail Creek is a south oriented Whitetail Creek tributary originating near headwaters of a north oriented tributary to the southeast oriented Boulder River. South of the south oriented Whitetail Creek segment are headwaters of south oriented Halfway Creek, which flows to southeast oriented Pipestone Creek, which is a Jefferson River tributary. Multiple through valleys link the south oriented Little Boulder River, Whitetail Creek, and Halfway Creek valleys, the Boulder River valley and Little Whitetail Creek valley, and numerous other study region valleys. The through valleys provide evidence of what were once diverging and converging flood flow channels that once crossed the study region. The flood flow channels were eroded as southeast and south oriented floodwaters derived from a thick North American ice sheet flowed from western Canada across Montana to the study region. The thick ice sheet was located in a deep “hole” and the ice sheet weight caused crustal warping that raised study region mountain ridges as floodwaters flowed across them and carved deep valleys into them. Headward erosion of deep southeast, northeast, and east oriented valleys, including headward erosion of the deep north oriented Missouri River valley from space in the deep “hole” being opened up by ice sheet melting, captured the south oriented flood flow and diverted floodwaters in other directions. Floodwaters on north ends of beheaded flood flow channels reversed flow directions to erode north oriented valleys. Barbed tributaries found throughout the study region provide further evidence of the flood flow captures and reversals.

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 are listed on the sidebar category list under their appropriate Missouri River tributary drainage basin, Missouri River segment drainage basin (by state), and/or state in which the Missouri River drainage basin is located.

Introduction

The purpose of this essay is to use topographic map interpretation methods to explore the Bison Creek-Boulder River drainage divide area landform origins in Jefferson County, Montana 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 Missouri River drainage basin landform origins research project essays 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 Bison Creek-Boulder River drainage divide area landform evidence in Jefferson County, Montana will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm.

Bison Creek-Boulder River drainage divide area location map

Figure 1: Bison Creek-Boulder River drainage divide area location map (select and click on maps to enlarge). National Geographic Society map digitally presented using National Geographic Society TOPO software.

Figure 1 provides a location map for the Bison Creek-Boulder River drainage divide in Jefferson County, Montana and illustrates a region in western Montana.The Missouri River is located in the east half of figure 1 and is formed at Three Forks (in southeast quadrant) at the confluence the north and northwest oriented Gallatin River, north oriented Madison River (not labeled), and the northeast, east, and northeast and east oriented Jefferson River. From Three Forks the Missouri River flows in a north and north-northwest direction to Canyon Ferry Lake and to the north edge of figure 1. North and east of figure 1 the Missouri River flows in a northeast and east direction to North Dakota where it turns to flow in a southeast and south direction with water eventually reaching the Gulf of Mexico. The Boulder River (unlabeled in figure 1) originates north of Butte and flows in a north direction before turning to flow in an east direction to the towns of Basin and Boulder. From the town of Boulder the Boulder River flows in a southeast and south-southwest direction to join the Jefferson River near Cardwell. Bison Creek is not shown in figure 1, but originates slightly north and east of Butte and flows in a north-northeast direction to join the Boulder River near the town of Basin. The Bison Creek-Boulder River drainage divide area illustrated and discussed in this essay is located between the north oriented Boulder River headwaters and the south oriented Boulder River segment east of Bison Creek. The Clark Fork-Boulder River drainage divide area along the continental divide north of Butte, Montana essay illustrates and discusses the region immediately to the west of the region illustrated and discussed here.

Before looking at detailed maps of the Bison Creek-Boulder River drainage divide area a brief look at the big picture erosion history is appropriate. Large volumes of south and southeast oriented floodwaters once flowed across the region shown by figure 1, including the present day north and west-northwest oriented Clark Fork drainage basin west of the continental divide. Floodwaters were derived from the western margin of a rapidly melting thick North American ice sheet and were flowing in a south and southeast direction from southwest Alberta and southeast British Columbia to and across the figure 1 region. At that time (at least initially) there were no high mountains in western Montana or in the region south of figure 1 and floodwaters could freely flow across locations that are today high mountain ranges. Western Canada, Montana, Wyoming, and other mountain ranges were formed by ice sheet related crustal warping and occurred as floodwaters flowed across the rising mountain masses. In addition, deep flood water erosion of valleys and basins surrounding the rising mountain ranges contributed to the emergence of present day mountain ranges.

In time the ice sheet related crustal warping combined with deep glacial erosion under the ice sheet created a deep “hole” in which the ice sheet was located. Eventually as the ice sheet melted there came a time when elevations on the ice sheet surface (at least in the south) were lower than elevations along the deep “hole” southwest rim where the immense south and southeast oriented ice marginal melt water floods were flowing. Deep northeast oriented valleys then eroded headward from space in the deep “hole” being opened up by the ice sheet melting to capture the south and southeast oriented melt water floods in present day Montana. The northeast oriented Missouri River valley segment (north and east of figure 1) and its east and northeast oriented tributary valleys eroded headward from the deep “hole” across the south and southeast oriented flood flow. Northwest oriented Missouri River tributary valleys and the north-northwest oriented Missouri River valley segment seen in figure 1 were eroded by reversals of flood flow on north and northwest ends of beheaded flood flow channels. The present day north oriented Madison River, north and northwest oriented Gallatin River, and north oriented Jefferson River tributary alignments were established initially as south oriented flood flow channels, which were reversed and deepened during a massive upper Missouri River drainage basin flood flow reversal. Uplift of the Yellowstone Plateau and mountain ranges south of figure 1 probably contributed significantly to the massive flood flow reversal. Headward erosion of the east oriented Jefferson River valley captured south oriented flood flow on the present day south oriented Boulder River alignment (and also on the alignment of south oriented Whitetail Creek, which joins the Jefferson River at Whitetail). The north oriented Boulder River and north-northeast oriented Bison Creek flow on the alignments of what began as south oriented flood flow channels. Floodwaters on north ends of those south oriented flood flow channels reversed flow direction when headward erosion of the much deeper east oriented Boulder River beheaded the south oriented flood flow channels.

Detailed location map for Bison Creek-Boulder River drainage divide area

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

Figure 2 provides a more detailed location map for the Bison Creek-Boulder River drainage divide area in Jefferson County, Montana and shows drainage routes not seen in figure 1. County boundaries are shown and Jefferson County is labeled. Green shaded areas are National Forest lands, which generally are located in mountainous regions. Butte is located in Silver Bow County in the southwest quadrant of figure 2. The east-west continental divide is labeled and extends in a south to north direction along the Jefferson County west boundary. The Boulder River originates on the north side of the continental divide  (where the continental divide is oriented in a west to east direction north of Butte) and flows in a north direction to near Blizzard Hill and then turns to flow in an east direction to the towns of Basin and Boulder before turning to flow in a southeast and south-southwest direction to join the Jefferson River near Cardwell (just west of Lewis and Clark Caverns). Basin Creek originates near Elk Park Pass (across the continental divide from Butte) and flows in a north-northeast direction to join the Boulder River west of the town of Basin. The Little Boulder River originates near Haystack Mountain and flows in a south direction toward Whitetail Reservoir, but makes an abrupt U-turn to flow in a northeast direction to join the Boulder River near the town of Boulder. Whitetail Creek flows in a south-southeast direction from Whitetail Reservoir to join the Jefferson River near the town of Whitetail. Little Whitetail Creek originates south of the town of Boulder and flows in a south direction west of Bull Mountain to join Whitetail Creek north of Whitetail. The remarkable U-turns made by the various drainage routes in the Bison Creek-Boulder River drainage divide area in Jefferson County provide evidence of one time south and southeast oriented flood flow channels that were beheaded and reversed by headward erosion of deep east and northeast oriented valleys. The north-northeast oriented Bison Creek alignment seen in figure 2 was once a major south-southwest oriented flood flow channel, which was reversed by crustal warping and headward erosion of the much deeper east oriented Boulder River valley to become a north oriented drainage route. South oriented streams, such as Whitetail Creek, Little Whitetail Creek, and the southeast and south-southwest oriented Boulder River segment document how headward erosion of the deep east oriented Jefferson River valley captured south oriented flood flow channels. The north oriented Boulder River segment and north-northeast oriented Basin Creek were formed by reversals along what had been south oriented flood flow channels.

Boulder River-Lowland Creek drainage divide area

Figure 3: Boulder River-Lowland Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 3 provides a topographic map of the Boulder River-Lowland Creek drainage divide area. County lines are shown with dashed lines and are labeled. Silver Bow County is located in the southwest quadrant of figure 3, Deer Lodge County is north of Silver Bow County in the west fourth of figure 3 and Jefferson County is north of Silver Bow County in the east half of the west half of figure 3 and occupies the entire east half of figure 3. The east-west continental follows the Jefferson County west border in the west half of figure 3. The Boulder River originates north of the east-west oriented Jefferson County-Silver Bow County line and east of the south to north oriented Jefferson County-Deer Lodge County line in the west half of figure 3 and flows in a north-northeast direction to near the north center edge of figure 3 and then in an east direction to the northeast corner of figure 3. Bison Creek flows through and from the large flat-floored valley in the southeast quadrant of figure 3 in a north-northeast direction to join the Boulder River near the northeast corner of figure 3. Sheepshead Mountain is a labeled mountain in the southeast quadrant of figure 3. The north-northeast and north oriented stream flowing from the Boy Scout Camp west of Sheepshead Mountain to join the Boulder River is Lowland Creek. Note how Lowland Creek has several south oriented tributaries flowing as barbed tributaries to the north oriented drainage route. These barbed tributaries include Swede Gulch and Olson Gulch from the west and Buffalo Gulch from the east. Also note northwest oriented tributaries to Lowland Creek, such as Sheep Creek and Cluney Gulch in the northeast quadrant of figure 3 . The north oriented Boulder River segment also has northwest oriented tributaries, including Northey Gulch. These tributaries provide evidence of southeast oriented flood flow channels that once crossed the region. The northwest oriented tributary valleys were eroded on the northwest ends of beheaded southeast oriented flood flow channels while the southeast oriented tributaries were eroded headward along the southeast ends of captured southeast oriented flood flow channels. The flood flow channels were probably first captured and/or beheaded by headward erosion of deeper south oriented flood flow channels, but those south oriented flood flow channels were subsequently beheaded and reversed by headward erosion of the much deeper east oriented Boulder River valley to form the north oriented Boulder River tributaries and headwaters seen today. In the case of the Bison Creek valley the south oriented flood flow crossed the continental divide at Elk Park Pass (north and east of Butte) and then flowed west along the Silver Bow Creek valley before flowing south across Deer Lodge Pass to what is today the north oriented Beaverhead River drainage basin. South oriented flood flow in the Lowland Creek valley converged with the south oriented flood flow in the Bison Creek valley near the south edge of figure 3. Note the through valley used by the southeast oriented road from the Boy Scout Camp to the Bison Creek valley.

Detailed map of Lowland Creek-Bison Creek drainage divide area

Figure 4: Detailed map of Lowland Creek-Bison Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 4 provides a detailed topographic map of the Lowland Creek-Bison Creek drainage divide area seen in less detail in figure 3. North oriented Lowland Creek joins the east oriented Boulder River in section 25 (near northwest corner of figure 4) and the Boulder River then flows in an east direction north of figure 4. Bison Creek flows in a north-northwest and north-northeast direction from the southeast corner to the northeast corner of figure 4. Note northwest oriented Lowland Creek tributaries from the east. These northwest oriented tributaries include Sheep Creek in the southwest quadrant of figure 4 and Cluney Gulch in the northwest quadrant of figure 4. Also note how those northwest oriented Lowland Creek tributary valleys are linked by through valleys (or mountain passes) with east and northeast oriented Bison Creek and Boulder River tributary valleys. Today the Lowland Creek-Bison Creek drainage divide may at first appear to be a significant topographic barrier. But the through valleys (or mountain passes) provide evidence of east oriented flood flow channels that once crossed the region. For example in section 32 a through valley links the northwest oriented Cluney Gulch valley with the northeast oriented Mormon Gulch valley and with the northeast and east oriented Wilder Gulch valley. The map contour interval for figure 4 is 40 feet and the through valley floor elevation at the drainage divide is between 7360 and 7400 feet. To the north the drainage divide rises to 7744 feet while to the south the drainage divide rises even higher suggesting the through valley is at least 244 feet deep. The through valley is a water eroded feature and was eroded at a time when the deep north oriented Lowland Creek valley to the west did not exist (nor did the deep east and north oriented Boulder River valley north and west of figure 4 exist). The flood flow channel diverged in the through valley area with one diverging flood flow channel continuing east to what was then the actively eroding north oriented Bison Creek valley (on the alignment of a newly beheaded and reversed flood flow channel that had previously been south oriented). The other diverging flood flow channel was oriented in a northeast direction toward what was then the actively eroding and much deeper east oriented Boulder River valley head.  Continued headward erosion of the much deeper east oriented Boulder River valley beheaded the southeast oriented flood flow channel and caused a reversal of flood flow on the northwest end of the beheaded flood flow channel to erode the northwest oriented Cluney Gulch valley.  Note the through valley in section 6 linking the Cluney Creek valley with the Sheep Creek valley. After the Cluney Gulch flood flow channel had been beheaded and reversed flood flow continued to move in a southeast direction on the Sheep Creek alignment and was captured by headward erosion of what was becoming the deeper northwest oriented Cluney Gulch valley. Southeast oriented flood flow on the Sheep Creek alignment was next beheaded and reversed by headward erosion of the deep north oriented valley on the Lowland Creek alignment, which before being beheaded and reversed had been a south oriented flood flow channel.

Bison Creek-Little Boulder River drainage divide area

Figure 5: Bison Creek-Little Boulder River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 5 illustrates the Bison Creek-Little Boulder River drainage divide area east and slightly south of figure 3 and includes an overlap area with figure 3. Bison Creek flows in a north-northeast direction from the south edge of the west half figure 5 to the north edge and is followed by the red highway. Haystack Mountain is located east of Bison Creek in the south half of figure 5. The Little Boulder River originates just east of Haystack Mountain and flows in a south direction to Little Boulder Park and then turns to flow in a northeast direction to the east edge of figure 5 (north half). East and north of figure 5 the Little Boulder River joins the Boulder River. The North Fork Little Boulder River originates near the center of figure 5 and flows in a northeast direction through Berrys Meadows before turning to flow in an east direction to join the Little Boulder River just east of figure 5. At the southwest end of Little Boulder Park there is a northeast to southwest oriented through valley linking the northeast oriented Little Boulder River valley with the southwest oriented Nez Perce Creek valley. Nez Perce Creek flows in a south, southwest, and northwest direction to join north-northeast oriented Bison Creek near the small town of Trask. South of Little Boulder Park and straddling the south center edge of figure 5 is Upper Whitetail Park, which will be seen again in figures 7 and 9. The south oriented stream originating in Upper Whitetail Park is Whitetail Creek, which flows in a south-southeast direction to join the Jefferson River. The map contour interval for figure 5 is 50 meters. Note how a through valley links the northeast oriented Little Boulder River valley with the south-southeast oriented Whitetail Creek valley. The figure 5 map also contains other through valleys. For example, a through valley links the North Fork Little Boulder River valley with Moose Meadows and Moose Creek, which flows in an east direction to the northeast oriented Little Boulder River. The through valley (floor elevation between 2150 and 2200 meters) is located between Haystack Mountain (elevation greater than 2650 meters) and Mount Pisgah (elevation greater than 2450 meters). A through valley in the Upper Bear Gulch Meadows area (near north center of figure 5) links the Bison Creek valley with the North Fork Little Boulder River valley. These and other through valleys provide evidence of deep flood flow channels that once crossed the region. At that time the deep northeast and east oriented Boulder River tributary valleys did not exist. The northeast and east oriented valleys eroded headward from the deep Boulder River valley to capture south and southeast oriented flood flow from west of the actively eroding and deep Boulder River valley head.

Detailed map of Little Boulder River-Nez Perce Creek drainage divide area

Figure 6: Detailed map of Little Boulder Rive-Nez Perce Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 6 provides a detailed topographic map of the Little Boulder River-Nez Perce Creek drainage divide area seen in less detail in figure 5. The Little Boulder River flows in a south-southeast direction from the north center edge of figure 6 into the northwest corner of section 12 and then turns to flow in a northeast direction to the northeast corner of figure 6. Nez Perce Creek originates in the northwest quadrant of section 10 and flows in a south direction to section 15 and then turns to flow in a southwest direction to the west edge of figure 6 (near southwest corner). Note how a through valley links the southwest oriented Nez Perce Creek valley with the northeast oriented Little Boulder River valley. Little Boulder Park is a relatively broad flat-floored area on the through valley floor. The map contour interval for figure 6 is 40 feet and elevations in the Little Boulder Park basin are in the 7280 to 7360 foot range. To the north elevations rise above 8600 feet while to the south elevations rise to more than 8120 feet. These elevations suggest the through valley is at least 760 feet deep. The through valley is a water-eroded feature and was probably eroded along a zone of geologic weakness (a fault line?) by floodwaters moving in a southwest direction to the Bison Creek valley and by floodwaters moving in a northeast direction to the Boulder River valley, although the northeast oriented Little Boulder River has probably been eroded along the alignment of what began as a southwest oriented flood flow channel. The north–northeast oriented Bison Creek valley (west of figure 6-see figure 5) originated as a south-southwest oriented flood flow channel and probably captured south and southeast oriented flood flow that had been moving to the southwest oriented flood flow on the Little Boulder River-Nez Perce Creek alignment. Evidence of the former south oriented flood flow channels can be seen near the corner of sections 3, 4, 9, and 10 where two parallel through valleys link north oriented streams with south oriented streams. While today these through valleys appear to be relatively minor features they are water-eroded features and were eroded by parallel south oriented flood flow channels, which were captured by headward erosion of the deep southwest oriented Nez Perce Creek flood flow channel.

Little Boulder River-Whitetail Creek drainage divide area

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

Figure 7 illustrates the Little Boulder River-Whitetail Creek drainage divide area east and somewhat south of figure 5 and includes an overlap area with figure 5. The Boulder River flows in a southeast direction across the northeast corner of figure 7. Whitetail Reservoir is located in Upper Whitetail Park in the southwest quadrant of figure 7 and Whitetail Creek flows in a south direction from Whitetail Reservoir to the south edge of figure 7 and then south of figure 7 to the Jefferson River. Little Boulder Park is north of Upper Whitetail Park and the Little Boulder River flows in a south direction to Little Boulder Park and then in a northeast direction to join the Boulder River just north of the north edge of figure 7. Note how north to south oriented through valleys link Little Boulder Park with Upper Whitetail Park. The map contour interval for figure 7 is 50 meters and the through valleys are bounded by four or more contour lines on a side. Bull Mountain is a labeled upland in the southeast quadrant of figure 7 and just west of Bull Mountain is the Whitetail Basin, which is drained by south oriented Little Whitetail Creek. Note how a north to south oriented through valley links the south oriented Little Whitetail Creek valley with a north oriented Boulder River tributary valley. The through valley floor elevation at the drainage divide is between 1700 and 1750 meters. Elevations on Bull Mountain to the east rise to more than 2500 meters while elevations to the west also rise to more than 2500 meters. While this through valley may be related to geologic structures it is also a water-eroded feature and was eroded by south oriented flood flow prior to headward erosion of the deep southeast oriented Boulder River valley. Headward erosion of the deeper Boulder River valley beheaded the south oriented flood flow to the Whitetail Basin and Little Whitetail Creek valley. Floodwaters on the north end of the beheaded flood flow channel reversed flow direction to erode the north oriented Boulder River tributary valley.  Also note how in the southeast quadrant of figure 7 (just north of Hay Canyon) Little Whitetail Creek flows through one south oriented valley while the road between Whitetail Creek and Bull Mountain uses an adjacent north to south oriented through valley. Another north to south oriented through valley can be seen west of Little Whitetail Creek (just west of the hill with the Airway Beacon).  These and other through valleys are evidence of diverging and converging south oriented flood flow channels such as might be found in a south oriented anastomosing channel complex. Headward erosion of the deep southwest oriented Nez Perce Creek-Little Boulder River flood flow channel first began to capture the south oriented flood flow in the Little Boulder Park region, but was interrupted by headward erosion of the deeper Boulder River valley, which beheaded and reversed south oriented flood flow to the Little Whitetail Creek valley after beheading and reversing the northeast end of the southwest oriented Nez Perce-Little Boulder River flood flow channel to create the northeast oriented Little Boulder River valley.

Detailed map of Little Boulder River-Whitetail Creek drainage divide area

Figure 8: Detailed map of Little Boulder River-Whitetail Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 8 provides a detailed topographic map of the Little Boulder River-Whitetail Creek drainage divide area seen in less detail in figure 7. The Little Boulder River flows in a south-southeast direction from the north edge of figure 8 (near northwest corner) to the northwest corner of section 12 and then turns to flow in a northeast direction to the north center edge of figure 8. North and east of figure 8 the Little Boulder River joins the Boulder River. Little Boulder Park is located in sections 11, 12 (northwest quadrant), and 2 (southeast corner). Upper Whitetail Park is the large non-forested flat area in sections 13 and 18 and which straddles the south edge of figure 8. South oriented drainage in Upper Whitetail Park is the headwaters of south oriented Whitetail Creek, which flows directly to the Jefferson River. Note how through valleys link the northeast oriented Little Boulder River valley with the south oriented Whitetail Creek drainage basin. The map contour interval for figure 8 is 40 feet. The deepest through valleys are located in the region where sections 1, 6, 7, and 12 sort of meet and have floor elevation of between 7360 and 7400 feet.  Elevations south of Little Boulder Park to the west rise to more than 8120 feet while equally high elevations can be found to the east of the through valleys. These elevations suggest the through valleys are as much as 720 feet deep, if not deeper. The through valleys were eroded by south oriented flood flow to the Whitetail Creek valley prior to headward erosion of the deeper northeast oriented Little Boulder River valley, which captured the south oriented flood flow and diverted the floodwaters in a northeast direction to what was then the actively eroding Boulder River valley. The flat-floored areas known as Little Boulder Park and Upper Whitetail Park appear to be areas where floodwaters deposited debris partially filling valley segments. Such deposition in the Upper Whitetail Creek drainage basin probably occurred because crustal warping was occurring as floodwaters flowed across the region and the crustal warping was uplifting areas downstream from figure 8 faster than the floodwaters could erode the downstream valley, which caused deposition in the valley upstream from the area being uplifted. As seen in the figure 9 the downstream uplift forced a diversion of the south oriented flood flow to create the present day Whitetail Creek drainage route. In the case of Little Boulder Park the explanation is probably more complex as floodwaters on the south oriented Little Boulder River valley alignment (in the northwest corner area of figure 8) first continued in a south direction to the actively eroding Whitetail Creek drainage basin, next flowed in a southwest direction to the southwest oriented Nez Perce Creek valley, and finally were captured by headward erosion of the deep northeast oriented Little Boulder River valley, although deposition of debris in the Little Boulder Park area probably was related to the deposition in the Upper Whitetail Park region.

Whitetail Creek-Halfway Creek drainage divide area

Figure 9: Whitetail Creek-Halfway Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 9 illustrates the Whitetail Creek-Halfway Creek drainage divide area south and west of figure 7 and includes an overlap area with figure 7. Bison Creek flows in a north-northeast direction across the northwest corner of figure 9. Upper Whitetail Park and Whitetail Reservoir straddle the north center edge of figure 9. Whitetail Creek flows in a south-southeast direction from Whitetail Reservoir to the east edge of figure 9 (near southeast corner). Note how the Whitetail Creek valley downstream from Whitetail Reservoir to Lower Whitetail Park (in east center area of figure 9) is narrow and deep when compared with the valley of the north oriented stream flowing to Whitetail Reservoir. In effect Whitetail Creek has eroded a deep water gap through the mountain ridge between Upper Whitetail Park and Lower Whitetail Park. The map contour interval for figure 9 is 50 meters and the Upper Whitetail Park elevation is between 2200 and 2250 meters. Elevations on the ridge north of the Whitetail Creek water gap rise to 2560 meters and to the southwest of the water gap the ridge elevations rise to more than 2600 meters. In other words the water gap is more than 300 meters deep. South of Upper Whitetail Park is Halfway Park. Halfway Creek originates in Halfway Park and flows in a south direction to the south center edge of figure 9. South of figure 9 Halfway Creek flows to southeast oriented Pipestone Creek, which then flows to the Jefferson River. Note how through valleys link the south oriented Halfway Creek valley with the north oriented stream valley draining to Whitetail Reservoir. Floors of these through valley are between 2250 and 2300 meters. Whitetail Peak to the west rises to 2689 meters while the unnamed mountain east of Halfway Park reaches an elevation greater than 2600 meters. The through valleys are at least 300 meters deep and were eroded by south oriented flood flow moving to the south oriented Halfway Creek valley. Whitetail Reservoir is located where two south oriented flood flow channels diverged, with one channel eroding the south-southeast oriented Whitetail Creek valley while the other flood flow channel eroded the south oriented Halfway Creek valley. Note how elevations in Halfway Park are similar to elevations in Upper Whitetail Park. Also note south-southeast oriented International Creek west of Halfway Park, which flows to Delmoe Lake. Through valleys link the Halfway Creek headwaters in Halfway Park with International Creek and provide evidence of still more diverging south oriented flood flow channels. Uplift of the ridge south of Halfway Park and the ridge east of Whitetail Reservoir apparently was the barrier than caused debris to accumulate in the Halfway Park and Upper Whitetail Park and which may also have contributed to the northeast diversion at Little Boulder Park to the Little Boulder River.

Detailed map of Whitetail Creek-Halfway Creek drainage divide area

Figure 10: Detailed map of Whitetail Creek-Halfway Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 10 provides a detailed topographic map of the Whitetail Creek-Halfway Creek drainage divide area seen in less detail in figure 9. Halfway Park is located in sections 11 and 12 in the south center area of figure 10. Halfway Creek flows in a south direction from Halfway Park to the south center edge of figure 10. International Creek flows in a south-southeast direction across the southwest corner of figure 10. The south end of Upper Whitetail Park is located in section 36 and straddles the north edge of figure 10. The north oriented stream flowing along the east edge of Upper Whitetail Park to the north edge of figure 10 flows to Whitetail Reservoir and is a barbed tributary to south-southeast oriented Whitetail Creek (not seen in figure 10). Note how in the southwest quadrant of section 1 a through valley links the east oriented headwaters of the north oriented Whitetail Creek tributary with a south oriented Halfway Creek tributary. The map contour interval for figure 10 is 40 feet and the through valley floor elevation is between 7440 and 7480 feet. Elevations in section 7 to the southeast of the through valley rise to 8560 feet and elevations in the northwest corner of figure 10 rise to more than 8440 feet with even higher elevations just north of the northwest corner of figure 10. These elevations suggest the through valley linking the south and south-southeast oriented Whitetail Creek valley with the south oriented Halfway Creek valley is as much as 1000 feet deep. Study of the drainage divide reveals numerous other through valleys suggesting not one, but many diverging and converging south oriented flood flow channels once crossed the region. Headward erosion of the deeper south-southeast oriented Whitetail Creek valley (north and east of figure 10) captured the south oriented flood flow and beheaded the flood flow moving to the Halfway Creek valley. Floodwaters on the north ends of the beheaded flood flow channels reversed flow direction to create the north oriented Whitetail Creek tributary seen today. Note also in section 10 (in southwest quadrant of figure 10) a through valley linking the Halfway Creek headwaters valley with the south-southeast oriented International Creek valley. Other through valleys crossing the Halfway Creek-International Creek drainage divide can also be seen. The entire figure 10 region was eroded by the south oriented flood flow, probably as crustal warping was raising the region. Initially floodwaters flowed on a surface now preserved, if it is preserved at all, by the highest figure 10 elevations seen 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 created and published by the United States Geologic Survey and can be obtained directly from the United States Geological Survey and/or from dealers offering United States Geological Survey maps. Hard copy maps can also be observed at United States Geological Survey map depositories, which are located throughout the United States and elsewhere. Illustrations used here were created using National Geographic Society TOPO software and digital map data. TOPO software and map data can be obtained from the National Geographic Society and/or dealers offering National Geographic Society digital map data.

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