Index
The Quaternary evolution of Herndon Bay in North Carolina is described in a paper by Moore, et al. (2016). The authors claim that geological investigations provide evidence that Herndon Bay has migrated by more than 600 meters and has left a regressive sequence of sand rims that partially backfill the remnant older portions of the bay. The following analysis shows that what appear to be older remnants of Herndon Bay are more likely to be different bays that have been overlaid by Herndon Bay.
Herndon Bay overlays a large portion of one bay, and a smaller portion of another bay. Moore, et al. have interpreted the sand rims of the overlaid bays as remnant rims of Herndon Bay at an earlier time, and the authors have postulated that the prevailing winds have caused the migration of the bay.
Statistical and geometrical analyses of the terrain can be used to show that what have been interpreted as previous rims of Herndon Bay are in reality the rims of other bays that have been overlaid. The image above shows Herndon Bay fitted with an ellipse that corresponds to the width-to-length ratio of the bay. Carolina Bays have a prototypical elliptical shape with width-to-length ratios of 0.58 ± 0.05 (Zamora, 2017)
A statistical analysis has to evaluate Herndon Bay in context with its geological surroundings. This helps to determine if Herndon Bay is really different from other bays, and whether it is migrating, or whether the bay is just overlaying other previously formed bays. The following image assigns numbers to the bays so that they can be analyzed.
Evaluation of Carolina Bay features
This is a statistical evaluation of bay features for a selected area with Herndon Bay (Lat. 34.861998°, Lon. -78.944526°) near the center.
The LiDAR data is from KMZ file for 1/4 Degree Grid Element 139315
(//cintos.org/Survey/index.html)
NOTE: Only bays with a major axis >200 m in the target area are considered for this exercise because smaller bays do not have distinct rims.
Guiding protocol for the area to be analyzed:
Results of the statistical evaluation.
Tot = 39
SR = 2 (bays: 31, 32) Proposed bays with secondary rims.
Ovr Notation: 5/11 indicates that bay 5 overlaps bay 11.
Ovr = 8 (bays: 5/11, 12/11, 13/11, 17/20, 21/20, 24/23, 31/30, 32/33)
SR/Tot = 0.051 = P(SR)
Ovr/Tot = 0.205 = P(Ovr)
There seems to be a big bay overlapped by 14, 15, 18 and 19 that was not counted, which would underestimate the number of overlaps. Another factor that causes the underestimation of overlapping bays is that the formation of large bays obliterates any smaller bays that may have been there previously.
From this cursory analysis we can state that the presumed "secondary" rim for bay 32 (Herndon Bay) is at least four times more likely to be the rim of a bay that was overlaid. Statistical analysis provides an objective way of classifying Carolina Bay features. The sample size can be increased by selecting a bigger area. The following image shows Herndon Bay and two other bays that it overlaid.
Herndon Bay (bay 32) has a major axis of 1070 m and a minor axis of 670 m, giving it a width-to-length ratio of 0.626. This ratio is within the range of 0.58 ± 0.05 reported in Zamora (2017) and corresponds to an ellipse of a cone inclined at approximately 38.8 degrees. The shape of bay 32 is elliptical with no evidence of geometrical deformation, which contrasts with the distorted geometry of bay 26. The lack of deformation of bay 32 from its prototypical elliptical shape may be considered evidence that the bay has not moved since its emplacement, whereas the deformation of bay 26 provides evidence of ground movement that stretched the shape of the bay.
The set of overlapping elliptical bays follow the geological law of superposition. Herndon Bay is a bay that was emplaced later in time. The image indicates the order in which the large bays were created according to this law. red:first, orange:next, yellow:last. By recognizing that the Carolina Bays are elliptical conic sections, it becomes mathematically possible to determine the shape of a partially obscured bay from 5 points along its curve. Thus, the rim southeast of bay 32, marked in orange, corresponds to a bay that was overlaid by Herndon Bay. From the fit of the orange ellipse, we can also see that the overlaid bay was actually smaller than Herndon Bay. The consistency of the statistical and geometrical analysis makes it difficult to draw another conclusion.
It is worthwhile noting that at least three small bays overlap the red ellipse. This was not mentioned by Moore, et al. The law of superposition requires that those small bays formed after the bay outlined in red.
Kaczorowski’s 1977 thesis.
Moore, et al. cite the thesis by Kaczorowski as being seminal work
demonstrating that Carolina bays evolve through the interactions of
strong, late Pleistocene directional winds on
shallow, ponded water, producing oriented
lakes. The authors affirm that through the
use of wind table modeling, Kaczorowski demonstrated that strong prevailing winds (from the
southwest in the Carolinas) were responsible
for creating circulation cells that shaped natural
depressions into ellipses and oriented bays perpendicular to prevailing wind.
The image below demonstrates the results of Kaczorowski's experiments.
Kaczorowski is to be lauded for trying to verify his eolian and lacustrine hypothesis by experiment, which is an essential step of the Scientific Method. Kaczorowski’s work preceded the paper by Zanner and Kuzila (2001) that reported the great similarity of the Nebraska Rainwater Basins to the Carolina Bays. Also, Kaczorowski’s work was done before the wide availability of LiDAR data revealed the pervasive elliptical geometry of the Carolina Bays with a narrow range of width-to-length ratios. The lack of these resources limited Kaczorowski to work with the information that he had at the time. Unfortunately, Kaczorowski’s wind and water experiment failed to produce the elliptical shape typical of the Carolina Bays, but Kaczorowski claimed otherwise in his description of the figure, as quoted here:
Figure 40. A diagramatic representation of model lake changes from circular to elliptical perpendicular to the influence of opposing winds alternated every fifteen minutes for a total of four hours. Sediment removed from the maximum transport zones along with sediment derived from near shore areas produced a net accretion in the areas where wave approach angle was low. Initial lake diameter was 65 cm.
Kaczorowski's experiment produced a structure pointy at both ends which does not have the geometrical characteristics of any Carolina Bay in existence. The following image shows an ellipse with the same width-to-length ratio as Herndon Bay superimposed on Kaczorowski's image. It is evident that the resulting structure is not a good fit.
Michael Davias’ comment on Cosmoquest.org (Sept. 2, 2014):
Raymond Kaczorowski's thesis (1977) is commonly referenced as the "wind and water" proof point. Unfortunately, it was never published except for a limited distribution by his institution's Geology Department. As such, it has never been held to any peer review, or open to a process of comment and rebuttal. With regard to the issue of wind direction and local dunes, he states this on p105:
"Therefore, while the shape and orientation of the Carolina Bays are a function of the prevailing southwest and northeast winds, the predominant westerly and north-westerly winds appear to be mainly responsible for producing the well recognized southeast dune rims."
Others have noted the disparity between the proposed normal-to-long-axis wind direction and that documented by local dunes. One explanation commonly given is that the dunes and the bays were created at different times.
Kaczorowski performed a scaled experiment on a sand table using a fan to simulate the glacial-era wind proposed. See his Figure 40 above. This experiment has not been successfully repeated for confirmation in a public document. Note the wind direction shown on the graphic — it denotes an alternating wind direction, reversing 180º at regular intervals during the experiment. In every reference I have seen to his "proof point" experiment, the alternating wind field is never referenced as Kaczorowski does in his explanation above (prevailing southwest and northeast winds). The current references are made to "Katabatic winds" flowing off the ice shield to the north, or cyclonic "Hurricane" winds, neither of which alternate in 180º patterns. It is conveniently overlooked, as such a regimen is hard to enforce. In any case, such a wind and wave regime requires (as in this experiment setup) a pre-existing shallow water-filled round depression.
I witnessed one attempt at re-creation, where the experiment was set up with a single fan blowing across the center of the "pond", and indeed a current was set up crossing the pond and being steered left and right at the other side. I pointed out that wind does not blow as a plume of air, but as a parallel wind field. When a second fan was introduced so as to provide a more parallel field of air, the circulating pattern stopped and the far side simply eroded across the entire half circle, and the far side of the puddle migrated away from the fan, as in the clam-shell type oriented bays in Chile. And the experimenter never even considered the 180º wind direction shift regimen.
Personal communication from M. Davias (Apr. 5, 2017)
Kaczorowski’s “experiment” has significant protocol errors.
First off, his experiment only works when one starts with a pre-existing round depression filled with water. Yea, 500,000 pre-existing round depressions… formed how?
But it does not end there. He used a wind mechanism consisting of an oscillating electric fan. His experiment moved it from one side of the bay to the 180º opposing position on a regular duty cycle. The mandate for opposing winds is NEVER addressed when folks regurgitate the result. Instead, they draw strong cyclonic winds with a fixed direction running over long periods, driven by ice sheet dynamics to the north. The term Katabatic winds is often invoked by the proponents, although they fail to recognize that such winds are downslope. In the case of a Laurentide ice sheet that should be north to south, not west to east. NO OSCILLATIONS, no 50-50 w-e, e-w duty cycles!
But it gets worse. His experiment does not generate a parallel wind field simultaneous across the entire width of the “bay”, but rather presents a stream of air unlike anything nature presents. this allows the fan to build up a catch across the center of the bay and allow the circulating vortexes to push a rotation of the water to either side of center. With a natural parallel wind field, what gets generated is the typical “clam shell” as the bay is effectively pushed away from the fan location.
At the 2012 GSA National Meeting in Charlotte, Mark Brooks tried to re-create Kaczorowski’s experiment in a vendor’s “water-erosion” box, and it failed miserably. The failure was primarily driven by my presence. After the setup was done, and a single rectangular “squirrel cage" fan was pumping the air in one direction across the center of the “round bay”. I pointed out the inconsistency to the table’s operator. The vendor took the second (idle) fan from the far side and placed the two side-by-side and spanning the ”bay” with a parallel wind field. Instantly the looping currents stopped.
The strongest argument I have is that Kaczorowski's experiment, although taken as scientific consensus “truth”, has never been duplicated by any researcher, and certainly never published. Even his seminal paper was never subjected to peer review — it was a thesis submission.
The Glacier Ice Impact Hypothesis
Based on the elliptical geometrical characteristics of the Carolina Bays
and their radial orientation toward the Great Lakes, Zamora (2017) proposed
that secondary impacts of ice boulders ejected by a meteorite impact on the Laurentide
Ice Sheet could have liquefied unconsolidated ground close to the water table, and
made it possible for the ejected ice impacts to create inclined conical cavities.
By contrast with Kaczorowski's experiments, oblique impact experiments on viscous soil produce inclined conical cavities that are remodeled into shallow elliptical depressions after viscous relaxation. The resulting structures bear a close resemblance to the elliptical geometry of the Carolina Bays because, mathematically, an ellipse is a conic section formed by the intersection of a plane and a cone.
The image above shows an inclined conical cavity fitted with an ellipse. After viscous relaxation, the conical structure will produce a shallow elliptical bay with raised rims typical of the Carolina Bays.
References
