"Uniformitarian geomorphologists seem to bounce from one hypothesis to another. They have tried the antecedent stream hypothesis, the superimposed stream hypothesis, even stream piracy. They are stuck in the rut of their failed paradigm."
"We must conclude the necessity of searching for an explanation within a completely different paradigm. Ironically, the features of these landforms readily can be explained by the great nemesis of modern geology- the Genesis Flood."
Selections from the first section of Origin of Appalachian Geomorphology, Part III: Channelized Erosion Late in the Flood, by Michael J. Oard.
(These selections by Marko Malyj are of the article published in Creation Research Society Quarterly Journal, Volume 48, Number 4, Spring 2012)
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Many master streams flow in deep gorges through ridges of resistant rock, with the Valley and Ridge of Pennsylvania having the most dramatic examples. The problem of how streams were able to cut through such obstacles has fascinated many geomorphologists.
Water gaps are numerous in the Appalachian Mountains (VerSteeg, 1930; Thompson, 1939; Strahler, 1945; Ahnert, 1998). Hundreds of them have been cut through resistant ridges (Thornbury, 1965). Speculation and controversy over the origin of water gaps have been going on for about 150 years. Although the major rivers Bow through water gaps of the Valley and Ridge and Blue Ridge Provinces, many tributary streams also Bow through water gaps, especially in the northern Appalachians (see Figures 23 and 24).
One of the most famous is the series through which the Susquehanna River flows. The river cuts through the folded and eroded ridges of Blue Mountain north of Harrisburg, Pennsylvania (Figure 4). The river, on the 37-km stretch upstream from Harrisburg, could have flowed around four out of five of the resistant ridges, had it followed the expected course at lower elevations over softer rocks (Strahler, 1945).
|Figure 4. Coogle Maps Image of Susquehanna River water gaps north of Harrisburg, Pennsylvania. Note that the last two water gaps are aligned and the third to the north is almost aligned (© Google 2010).|
Figure 9. Shaded relief map of New River. Downstream toward top. Note that the river cuts almost straight through the Valley and Ridge Province(© Google 2010).
Uniformitarian Hypotheses and Problems
A water gap is "a deep pass in a mountain ridge, through which a stream flows; esp. a narrow gorge or ravine cut through resistant rocks" (Neuendorf et al., 2005, p. 715). This applies to any perpendicular cut through any topographical barrier, including a plateau (Douglas, 2005).
There are five uniformitarian hypotheses for the origin of water gaps, also called transverse drainage (Oberlander, 1965). William Morris Davis was one of the first to attempt an explanation in the early twentieth century, by relief inversion plus reversal in drainage. This explanation is not taken seriously today. The second is that gaps are the surface expression of faults cutting through the mountains. However, most water gaps in the Appalachians are erosional and cannot be attributed to faulting. In fact, many well-known faults have not resulted in water gaps (e.g., Strahler, 1945, pp. 46, 63-65).
That leaves three current uniformitarian hypotheses: (1) the antecedent stream, (2) the superimposed stream, and (3) stream piracy (Stokes and Mather, 2003, p. 76).
Antecedent Stream Hypothesis
The antecedent stream hypothesis, defined above and illustrated in Figure 1, seems to have been the first invoked to explain transverse drainage. John Wesley Powell simply assumed the Green River
through the Uinta Mountains and the Colorado River through Grand Canyon had been eroded by antecedent rivers. Most other geologists accepted this hypothesis until the mid 1900s, when
it ran into severe problems.
|Figure 1. The antecedent stream hypothesis shown on a plaque near a Yakima River water gap, Washington. First, a stream is established; then, as a ridge slowly uplifts, the stream erodes through the barrier.|
(Ranney, 2005). If uplift was too rapid, a river in an enclosed basin would become a lake. If a water gap through one barrier is difficult to achieve, aligned water gaps through multiple uplifts, such as on the Susquehanna north of Harrisburg (Figure 15), would be much less likely.
|Figure 15. Coogle Maps close-up view of aligned water gaps of the Susquehanna River north of Harrisburg, Pennsylvania.|
Superimposed Stream Hypothesis
In the superimposed stream hypothesis, a landscape is buried by renewed sedimentation, usually by a marine transgression. Then, a stream or river is established on the generally flat cover of sediments or sedimentary rock, called the "covermass." As erosion takes place over millions of years, the stream erodes downward in the same location (Figure 2). In that way, after millions of years, the stream ends up flowing through structural barriers. At the same time, the rest of the covermass not in the path of the river is somehow eroded or mostly eroded, leaving behind the stream or river flowing through ridges or mountains. If so, that surface would have been generally level, and rivers flowing across it were assumed to have cut down into older deformed sedimentary rocks.
|Figure 2. Block diagram of the superimposed stream hypothesis. The stream maintains its same course as most of the covermass (top layer) is eroded. Drawing by Bryan Miller.|
What is actually observed is that many tributaries do flow parallel to the ridges, but then they mysteriously jump across ridges through water gaps. Von Engeln (1942) also pointed to the aligned water gaps as evidence of superimposition, since these features would not be likely caused by antecedence or stream piracy.
The most significant problem is the absence of evidence for the proposed transgression, the great volume of "covermass." Cretaceous marine deposits do not occur within the Appalachian fold belt (Kaktins and Delano (1999, p. 382). Another difficulty is the tendency of modern rivers to take the path of least resistance. We would expect a downward-cutting river to change course as it encountered a more resistant anticline, and flow through the more easily eroded covermass.
Superimposition has a problem with removing the covermass in between the rivers. If the rivers are cutting vertically, then why would we expect laterally extensive erosion of these sediments on the ridges between the rivers? The hypothesis requires the river to maintain the same course and
downcut into both resistant and nonresistant formations, while at the same time having the drainage basin erode the covermass all across the remainder of the region. Thus, the soft rocks are cut into valleys and leave the more resistant rocks as ridges, while the main rivers do not change course through the ridges (Crickmay, 1974 ).
|Figure 3. Schematic of stream piracy drawn by Peter Klevberg. As the stream valleys erode, a tributary stream supposedly erodes through the intervening ridge and eventually captures part of the stream on the other side of the divide.|
The final piracy experiment successfully produced a transverse drainage through headward erosion, but required the retreat of a strongly asymmetrical scarp ridge and required much more time than the other experiments. This supports Bishop's (1995) argument concerning piracies over utilization.All Uniformitarian Hypotheses Fail
Hack (1989) acknowledged that the origin of water gaps has not been explained, despite all the attempts. Uniformitarian geomorphologists seem to bounce from one hypothesis to another, stuck in the rut of their failed paradigm.
"What was written in 1932-33 can still be quoted today: 'The Appalachian problem, like the poor, we shall have with us always.'" (Bryan etal., 1932/3 3, p. 318, quoted in Clark, 1989, p. 225, 229).
If all of the classical uniformitarian hypotheses are insufficient, then we must conclude the necessity of searching for an explanation within a completely different paradigm. Ironically, the features of these landforms readily can be explained by the great nemesis of modern geology - the Genesis Flood.
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