scholarly journals North Platte River-South Platte River Confluence Area Drainage System History as Determined by Topographic Map Interpretation: Western Nebraska, USA

2020 ◽  
Vol 12 (2) ◽  
pp. 28
Author(s):  
Eric Clausen
Keyword(s):  
Drainage System ◽  
River Valley ◽  
New Paradigm ◽  
Platte River ◽  
Nebraska Sand Hills ◽  
South Platte River ◽  
River Confluence ◽  
Sand Hills ◽  
South Platte ◽  
North And South

Detailed topographic maps of the western Nebraska North Platte River-South Platte River confluence area show a low relief and gently sloping southeast-oriented upland surface, asymmetrical drainage divides, nearly adjacent and parallel east-oriented North and South Platte River valley segments, barbed tributaries, and shallow divide crossings (low points along drainage divides) in a region south of the Nebraska Sand Hills and at the Nebraska loess region’s western margin. Published interpretations of North and South Platte River confluence area landforms (referred to as the accepted paradigm) do not explain most drainage features and are compared with a new paradigm’s interpretations to determine which of the two paradigms explains the regional drainage history and related surface features in a simple and consistent manner. New paradigm interpretations require large sheets of slowly-moving southeast-oriented water to have flowed toward what was probably an actively eroding Republican River valley and to have shaped the upland surface while the Platte and North and South Platte River valleys eroded headward into and across the region so as to create the asymmetric drainage divides, barbed tributaries, and shallow divide crossings. These new paradigm interpretations are consistent with each other and with recently published new paradigm interpretations of upstream North and South Platte River drainage system history. New paradigm interpretations also suggest the adjacent Nebraska Sand Hills developed on a large flood deposited delta (typical of sand dune areas on former glacial lake deltas further to the north) and the slowly-moving sheets of water may have been responsible for some or all of Nebraska’s loess deposits, although the new paradigm leads to a fundamentally different middle and late Cenozoic regional geologic and glacial history than what workers using the accepted paradigm have described.

Geochemical Evidence for an Eolian Sand Dam across the North and South Platte Rivers in Nebraska

2000 ◽  
Vol 53 (2) ◽  
pp. 214-222 ◽  
Author(s):  
Daniel R. Muhs ◽  
James B. Swinehart ◽  
David B. Loope ◽  
Josh Been ◽  
Shannon A. Mahan ◽  
...  
Keyword(s):  
The South ◽  
Platte River ◽  
Nebraska Sand Hills ◽  
South Platte River ◽  
The North ◽  
Eolian Sand ◽  
Lincoln County ◽  
Sand Hills ◽  
South Platte ◽  
North And South

AbstractGeochemical and geomorphic data from dune fields in southwestern Nebraska provide new evidence that the Nebraska Sand Hills once migrated across the North and South Platte rivers and dammed the largest tributary system to the Missouri River. The Lincoln County and Imperial dune fields, which lie downwind of the South Platte River, have compositions intermediate between the Nebraska Sand Hills (quartz-rich) and northeastern Colorado dunes (K-feldspar-rich). The most likely explanation for the intermediate composition is that the Lincoln County and Imperial dunes are derived in part from the Nebraska Sand Hills and in part from the South Platte River. The only mechanism by which the Nebraska Sand Hills could have migrated this far south is by complete infilling of what were probably perennially dry North Platte and South Platte river valleys. Such a series of events would have required an extended drought, both for activation of eolian sand and decreased discharges in the Platte River system. A nearby major tributary of the North Platte River is postulated to have been blocked by eolian sand about 12,000 14C yr B.P. We propose that an eolian sand dam across the Plattes was constructed at about this same time.

scholarly journals Gravel deposits of the South Platte River valley north of Denver, Colorado

1998 ◽  
Author(s):  
David A. Lindsey ◽  
William H. Langer ◽  
Linda Scott Cummings ◽  
John F. Shary ◽  
Joseph E. Taggart ◽  
...  
Keyword(s):  
River Valley ◽  
The South ◽  
Platte River ◽  
South Platte River ◽  
South Platte ◽  
Platte River Valley

scholarly journals Topographic Map Analysis of the North Platte River-South Platte River Drainage Divide Area, Western Larimer County, Colorado, USA Eric Clausen

2021 ◽  
Vol 10 (1) ◽  
pp. 49
Author(s):  
Eric Clausen
Keyword(s):  
Colorado River ◽  
The United States ◽  
River Valley ◽  
Topographic Map ◽  
Platte River ◽  
River Drainage ◽  
South Platte River ◽  
The North ◽  
Cache La Poudre River ◽  
South Platte

The United States Supreme Court settled legal disputes concerning four different Larimer County (Colorado) locations where water is moved by gravity across the high elevation North Platte-South Platte River drainage divide, which begins as a triple drainage divide with the Colorado River at Thunder Mountain (on the east-west continental divide and near Colorado River headwaters) and proceeds in roughly a north and northeast direction across deep mountain passes and other low points (divide crossings) first as the Michigan River (in the North Platte watershed)-Cache la Poudre River (in the South Platte watershed) drainage divide and then as the Laramie River (in the North Platte watershed)-Cache la Poudre River drainage divide. The mountain passes and nearby valley and drainage route orientations and other unusual erosional features can be explained if enormous and prolonged volumes of south-oriented water moved along today’s north-oriented North Platte and Laramie River alignments into what must have been a rising mountain region to reach south-oriented Colorado River headwaters. Mountain uplift in time forced a flow reversal in the Laramie River valley while flow continued in a south direction along the North Platte River alignment only to be forced to flow around the Medicine Bow Mountains south end and then to flow northward in the Laramie River valley and later to be captured by headward erosion of the east-oriented Cache la Poudre River-Joe Wright Creek valley (aided by a steeper gradient and less resistant bedrock). Continued uplift next reversed flow on the North Platte River alignment to create drainage routes seen today. While explaining Larimer County North Platte-South Platte drainage divide area topographic map drainage system and erosional landform evidence this interpretation requires a completely different Cenozoic history than the geologic history geologists usually describe.

scholarly journals Topographic Map Analysis of Mountain Passes Crossing the Continental Divide Between Colorado River Headwaters and North and South Platte River Headwaters to Test a New Geomorphology Paradigm, Colorado, USA

2020 ◽  
Vol 12 (1) ◽  
pp. 50
Author(s):  
Eric Clausen
Keyword(s):  
Colorado River ◽  
Drainage Basin ◽  
Mountain Range ◽  
Platte River ◽  
River Drainage ◽  
South Platte River ◽  
Continental Divide ◽  
South Platte ◽  
North And South ◽  
River Drainage Basin

Detailed topographic maps are used to identify and briefly describe named (and a few unnamed) mountain passes crossing high elevation east-west continental divide segments encircling south- and southwest-oriented Colorado River headwaters and linking the Colorado River drainage basin (draining to the Pacific Ocean) with the North and South Platte River drainage basins (draining to the Platte, Missouri, and Mississippi Rivers and Gulf of Mexico). Previous researchers following commonly accepted geomorphology paradigm rules have not explained how most, if any of these mountain passes originated. A recently proposed geomorphology paradigm requires all Missouri River drainage basin valleys to have eroded headward across massive south- and southeast-oriented floods, which implies south- and southeast-oriented floods flowed from what are today north-oriented North Platte River headwaters across the continental divide, the present-day south- and southwest-oriented Colorado River headwaters valley, and then across what is now the continental divide a second time to reach east- and southeast-oriented South Platte River headwaters. Paradigms are rules determining how a scientific discipline governs its research and by themselves are neither correct nor incorrect and are judged on their ability to explain observed evidence. From the new paradigm perspective, a stream eroded each of the passes into a rising mountain range until the uplift rate outpaced the erosion rate and forced a flow reversal in what would have been the upstream valley. The passes and the valleys leading in both directions from the continental divide are best explained if diverging and converging south- and southeast-oriented flood flow channels crossed rising mountain ranges. While explaining observed drainage patterns and erosional landforms such an interpretation requires a fundamentally different regional middle and late Cenozoic glacial and geologic history than what previous investigators using the accepted paradigm perspective have described.

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