How a New Geology and Glacial Paradigm Explains Colorado South Platte-Arkansas River Drainage Divide Topographic Map Evidence, USA

Eric Clausen

doi:10.4236/ojg.2021.1111029

Abstract

United States Geological Survey (USGS) topographic maps (available at the USGS National Map website) are used to determine development of the asymmetric South Platte River drainage basin (south of Denver) by noting low points (referred to as divide crossings) where south-oriented floodwater channels once crossed the South Platte-Arkansas River drainage divide. Twelve groups of observed divide crossings are described most of which show evidence for flood-formed diverging and converging channels including where divide crossings are cut across Thirtynine Mile volcanic field ejectamenta. A new Cenozoic geologic and glacial history paradigm requires southeast- and south-oriented floods to have flowed across what is now the east-west continental divide to reach the southeast-oriented Arkansas River valley and to have eroded the divide crossings before north-oriented South Platte River valley headward erosion captured the flow. Such floods are not consistent with accepted Cenozoic geologic and glacial history interpretations, but are consistent with new paradigm interpretations (developed to explain Missouri River drainage basin topographic map drainage system evidence) in which a thick continental ice sheet (located where large continental ice sheets are usually reported to have been) deeply eroded the underlying bedrock and caused crustal uplift to create a deep “hole” with a deep “hole” rim segment roughly following today’s Wyoming and northern Colorado east-west continental divide and then continuing eastward along what is now the Missouri-Arkansas River drainage divide. The new paradigm results in a Cenozoic geologic and glacial history in which immense south-oriented continental ice sheet meltwater floods first flowed in a south direction across the rising deep “hole” rim and were then forced by rim uplift to flow along the rim and subsequently in north directions into the developing deep “hole”.

Highlights

IntroductionThe geologic research community’s failure to say much about South Platte River drainage system history is intriguing because published reports say much more about the regional geologic structures, stratigraphy, volcanic activity, economic resources, and paleontology than they say about the regional drainage history
Supporting an interpretation that diverging and converging flood flow channels eroded the deep valleys on either side of the ridge is a high-altitude divide crossing between north- and east-oriented Rich Creek and north- and northeast-oriented Rough and Tumbling Creek, both flowing to the South Fork South Platte River which when viewed with similar divide crossings to the north suggests a south-oriented stream of water once flowed from Weston Pass along what are the north-oriented Rich Creek and Rough and Tumbling Creek segment alignments and into the southoriented Fourmile Creek valley, which joins the south-southeast oriented Arkansas River
With the exception of DC-1, DC-13, DC-14 and DC-15 all of the described divide crossings suggest large floods of south-oriented water flowed from the northoriented South Platte River drainage basin into the southeast- and east-oriented Arkansas River drainage basin while DC-13, DC-14 and DC-15 suggest the north-oriented South Platte River valley originated as a south-oriented flood flow channel

Summary

Introduction

The geologic research community’s failure to say much about South Platte River drainage system history is intriguing because published reports say much more about the regional geologic structures, stratigraphy, volcanic activity, economic resources, and paleontology than they say about the regional drainage history. Two recent Colorado Geological Survey reports [1] [2] describe Park County geology but hardly mention the regional drainage history even though significant regional South Platte River drainage history events must have occurred. This failure to determine regional drainage histories is not unique to the South Platte River headwaters region and shows up in geologic literature pertaining to most other drainage systems. While geologists rarely say so, they are reluctant to determine regional drainage histories because the drainage histories determined from detailed topographic maps (on which drainage history evidence is most observed) frequently do not agree with commonly accepted Cenozoic geology and glacial history paradigm (accepted paradigm) interpretations

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Conclusion