Figure 7 - uploaded by Eric Clausen
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USGS 1:24,000 topographic map (with 10-foot contour interval in west and 20-foot contour interval in the east) taken from Pennsylvania DCNR Interactive Map Resources website showing Davis home location (1), Tookany (Tacony) Creek valley downstream from Jenkintown (2), Mill Run headwaters (3), Tookany (Tacony) Creek Cheltenham direction change location (4), Cedar Brook headwaters (5), Jenkintown Creek (6), and an unnamed south oriented Tookany (Tacony) Creek tributary (7)
Source publication
Topographic map interpretation methods are used to determine erosional landform origins in and adjacent to the Tookany (Tacony) Creek drainage basin, located upstream from and adjacent to Philadelphia, PA. Five wind gaps notched into the Tookany-Wissahickon Creek drainage divide (which is also the Delaware-Schuylkill River drainage divide), a deep...
Contexts in source publication
Context 1
... Davis probably was most familiar with the Tookany Creek valley downstream from Jenkintown (see figure 7) simply because it was closest to the Davis family home and would have been an attraction not only for recreation, but also for any young person developing an interest in the natural sciences. In addition young Davis probably had excellent access to much of the land in this area as his father, in addition to his coal company interests, also headed the Chelten Hills Land Association, which in 1854 purchased 1000 acres of farmland between the railroad and the Philadelphia city line, including lands adjoining the Tookany Creek valley (Rothschild, 1976, p. 68). ...
Context 2
... several features seen in figure 7 suggest the Tookany Creek valley had a very different history than the modern day erosion rates suggest. First is Mill Run, a northeast oriented Tookany Creek tributary originating south of the former Davis home and joining the southeast oriented Tookany Creek segment downstream from Elkins Park. ...
Context 3
... evidence suggests the south oriented tributary valleys eroded headward across southwest oriented flow moving water into the newly eroded Tookany Creek valley with the unnamed south oriented tributary capturing the flow first and headward erosion of the south oriented Jenkintown Creek valley capturing the southwest oriented flow next. While not seen in figure 7, Pennypack Creek valley headward erosion east of figure 7 beheaded all southwest oriented flow to the Jenkintown Creek valley. ...
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Citations
... Recent papers have presented topographic map evidence suggesting the Tookany-Tacony-Frankford Creek valley (Clausen, 2016a), Pennypack Creek valley (Clausen, 2017a), Wissahickon Creek valley (Clausen, 2016b), lower Neshaminy Creek valley (Clausen, 2017b), and Schuylkill River valley (Clausen, 2017c) eroded headward across a large complex of southwestoriented diverging and converging channels, such as might be found in a flood formed anastomosing channel complex. Headward erosion of deep south-oriented valleys across massive southwest-oriented flood flow is a productive hypothesis explaining previously unexplained landforms such as drainage divides, valley orientations, wind gaps, water gaps, deep gorges, asymmetric divides, barbed tributaries, and valleys extending across present day drainage divides (referred to in this paper as through valleys). ...
... While the hypothesis offers excellent erosional landform origin explanations, it requires the movement of immense quantities of water across the region in massive and prolonged floods. Such massive and prolonged floods across southeast Pennsylvania, with the exception of Clausen (2016a;2016b;2017a;2017b;2017c), have not been previously described and the floodwater source is unknown other than that it was to the north or northeast of this paper's study region. Based on known geologic events, the most likely floodwater source would be rapid melting of a large continental ice sheet. ...
Detailed topographic map evidence is used to test a recently proposed hypothesis that deep valleys eroded headward across massive and prolonged southwest-oriented floods to create what are today the Neshaminy Creek-Perkiomen Creek and the To-hickon Creek-East Branch Perkiomen Creek drainage divide segments of the Delaware River-Schuylkill River drainage divide. The hypothesis was found to be extremely productive in terms of its ability to explain previously unexplained valley and drainage route orientations, through valleys (defined here as valleys that extend across present day drainage divides), barbed tributaries, asymmetric divides, incised meanders, and drainage divide origins. Further the hypothesis explains how and why many southeast Pennsylvania drainage routes cut across geologic structures and do not follow zones of more easily eroded bedrock. The source of the hypothesized immense and prolonged southwest oriented floods was not determined, but may have been a large and rapidly melting North American continental ice sheet.
... Detailed study of erosional landforms contained within and surrounding a modern day drainage basin, such as the Pennypack Creek drainage basin, can identify significant erosion events independently of sediment deposits and by doing so determine whether the described sedimentary record, if there is one, has identified all erosion events (and also determine whether the sediment record has been correctly interpreted). In the Piedmont Province Upland Section the smaller south oriented Tookany (Tacony) drainage basin is directly west of the Pennypack drainage basin and was determined by Clausen (2016) to have formed when headward erosion of the south oriented Tookany Creek valley captured southwest and west oriented floods. Prior to being captured floodwaters flowed in shallow diverging and converging channels formed on a low gradient topographic surface equivalent in elevation to highest regional elevations today. ...
Topographic map evidence is used to interpret Pennypack Creek drainage basin erosion history in and north of the City of Philadelphia, Pennsylvania (USA). Southwest and west-southwest oriented through valleys crossing the south oriented Pennypack Creek drainage basin, barbed Pennypack Creek tributaries, and significant valley direction changes are used to determine that the Pennypack Creek valley eroded headward across massive southwest oriented floods. Initially floodwaters flowed on a low gradient topographic surface at least as high, if not higher, than the highest Pennypack Creek drainage basin elevations today. Shallow low gradient diverging and converging flow channels were eroded into the underlying bedrock surface predominantly along fault lines and other zones of easier to erode materials. Headward erosion of the much deeper Pennypack Creek valley across this anastomosing channel complex captured southwest oriented floodwaters and flow on northeast ends of beheaded channels was reversed so as to move toward the newly eroded and deeper Pennypack Creek valley. These reversed flow channels captured southwest oriented floodwaters still moving north of the actively eroding Pennypack Creek valley head. This captured water then moved in a northeast direction and eroded deep northeast oriented valleys headward from the newly eroded Pennypack Creek valley. These valleys today account for northeast and east oriented Pennypack Creek valley segments and northeast oriented (barbed) tributaries flowing to south oriented Pennypack Creek. The floodwater source cannot be determined from Pennypack Creek drainage basin evidence, but was from the northeast. Melting of a continental ice sheet could produce floods of sufficient volume and duration to overwhelm whatever drainage system previously existed and to erode new drainage basins in a manner similar to how the Pennypack Creek drainage basin was eroded.
... Chirico, P.G. and Epstein, J.B, 2000: Evans, Sheeder, and Lehning, 2003: and Cianfrani, Hession, and Rizzo, 2006 and there are studies of erosion rates in nearby Pennsylvania Piedmont river valleys (e.g. Reusser, L. Bierman, P., Pavich, M., Larsen, J., and Finkel, R., 2006), however the only recent literature found asking the types of questions being asked in this paper was written by the author of this paper (Clausen, 2016). Questions asked in this paper include: what type of drainage system crossed the Wissahickon drainage basin area before the Wissahickon Creek drainage basin existed, why does the south oriented Wissahickon Creek valley cut across geologic structures including some higher in elevation than the Wissahickon Creek headwaters, why do the Wissahickon Creek headwaters first flow in a southwest direction and then turn in an east direction before turning in a south direction, and how and why was the Wissahickon Creek drainage basin eroded? ...
... The west oriented Wissahickon tributary flows through a water gap (marked by the letters "WG") cut across the Edge Hill quartzite ridge while Tookany (Tacony) Creek near Jenkintown turns abruptly in a south direction at an obvious elbow of capture. Clausen (2016) suggests prior to headward erosion of the deep south oriented Tookany (Tacony) Creek valley all regional elevations were high enough that diverging and converging flow channels crossed the present day Edge Hill quartzite ridge (highest elevations exceed 420 feet today). Wind gaps numbered 2 (350-360 feet) and 3 (320-330 feet) were initiated by water moving into the Chester Valley area while wind gap 4 (320-330 feet) and an unseen wind gap east of Figure 4 were initiated by water moving from the Chester Valley area to the southeast side of today's ridge and drainage divide. ...
Topographic map interpretation methods are used to determine the Wissahickon Creek drainage basin origin. Wissahickon Creek flows for approximately 23 miles in a south direction to join the Schuylkill River in northwest Philadelphia. Wind gaps, through valleys, and saddles notched into drainage divides surrounding the Wissahickon drainage basin combined with orientations of valleys leading to and from those divide crossings document how the Wissahickon Creek valley and adjacent south oriented valleys eroded headward across multiple flood formed southwest oriented channels. Massive southwest oriented flood flow initially moved across the region on a topographic surface as high or higher than the highest regional elevations seen today. Headward erosion of south oriented valleys into this surface captured the floodwaters and lowered base level, which enabled the southwest oriented flow to significantly lower elevations in the Piedmont Province Gettysburg-Newark Section and Chester Valley. Headward erosion of the south oriented Wissahickon valley beheaded and in some cases reversed southwest oriented flow channels that had been supplying water to the southeast oriented Schuylkill River. Rapid erosion of the Wissahickon drainage basin ended when headward erosion of the southeast and south oriented Neshaminy Creek valley beheaded southwest oriented flow routes to the Wissahickon valley.
The book describes and illustrates with color maps examples of large-scale and well-mapped United States Geological Survey topographic map drainage system and erosional landform evidence found throughout the United States which the geology research community’s Cenozoic geology and glacial history paradigm cannot satisfactorily explain and which the geology research community has almost completely ignored. The book also describes a new Cenozoic geology and glacial history paradigm which appears to be able to explain the topographic map drainage system and erosional landform evidence which the geology research community's accepted Cenozoic geology and glacial history paradigm has been unable to explain. The topography map mystery is: does unexplained and ignored topographic map drainage system and erosional landform evidence support the Cenozoic geologic and glacial history story the geology research community usually tells or does unexplained and ignored topographic map drainage system and erosional landform evidence tell a completely different Cenozoic geologic and glacial history story? The 146-page book is available in e-book, softcover, and hardcover editions at on-line booksellers such as Amazon and Barnes and Noble. An e-book copy in pdf format can be obtained without cost by contacting at eric2clausen@gmail.com.
