The Carolina Bays and the Nebraska Rainwater Basins are elliptical features oriented toward the Great Lakes. Their convergence point is a clue about the location of an extraterrestrial impact on the Laurentide Ice sheet that launched pieces of glacier ice in ballistic trajectories. The secondary impacts of the ice boulders created inclined conical cavities that became shallow elliptical bays by viscous relaxation.
The Carolina Bays and the Nebraska Rainwater Basins are elliptical features oriented toward the Great Lakes. Their convergence point is a clue about the location of an extraterrestrial impact on the Laurentide Ice sheet that launched pieces of glacier ice in ballistic trajectories. The secondary impacts of the ice boulders created inclined conical cavities that became shallow elliptical bays by viscous relaxation. In this presentation, I will review some publications that have examined the headings of the Carolina Bays to determine the location of the extraterrestrial impact.
The first systematic study of the Carolina Bays was published by Professors Melton and Schriever from the University of Oklahoma in 1933 with the title "The Carolina Bays – are they meteorite scars?" The abstract says: "Aerial photographs of a district on the coastal plain of South Carolina reveal hitherto unknown relationships among surface depressions of a particular type, the origin of which has long been a subject of speculation. These relationships include 1) a smoothly elliptical shape, 2) parallel alignment in a southeastern direction, 3) a peculiar rim of soil which, with unimportant exceptions, is invariably larger at the southeastern end than elsewhere, and 4) mutual interference of outline. Consideration of all of these facts leads to the conclusion that the origin is not directly attributable to ordinary geologic processes. On the contrary, a hypothesis involving impact by a cluster of meteorites is presented as the most reasonable explanation."
Working from aerial maps, Melton and Schriever found that the bays are nearly parallel with a mean direction of south 46 degrees east, which corresponds to an azimuth of 136 degrees. The authors say: "The average of the deviations from the mean direction is 3.08 degrees. Since the allowable error in determining the long axis of a bay is greater than this amount, it is apparent that the degree of parallelism is striking." Melton and Schriever always described the Carolina Bays as elliptical and defined a measure of ellipticity.
In 1942, Professor Douglas Johnson from Columbia University proposed that the Carolina Bays had been created by a complex process where lakes that formed from artesian springs were later modified by wind and water mechanisms. Professor Johnson consistently characterized the Carolina Bays as oval and refused to call them elliptical throughout his book. Johnson objected to the meteor impact hypothesis by Melton and Schriever, and his study of the axial orientation was intended to refute the hypothesis by showing that the orientations of the bays were not parallel as required by a meteor shower. Johnson's measurements of axial directions of 75 bays from North Carolina to Georgia showed a wide range of orientations.
In 1975, Eyton and Parkhurst tried to revive the impact hypothesis in a paper titled "A re-evaluation of the extraterrestrial origin of the Carolina Bays." The abstract says: "Controversy as to the origin of the Carolina Bays has centered on terrestrial versus extraterrestrial theories. Meteoritic impact has been considered the primary causal mechanism in extraterrestrial models, but alternatives such as comets and asteroids have not been adequately considered. Comets may explode during fall and produce depressions which would conform to the morphology of the Bays. Only a comet appears to satisfy the constraints imposed both by extraterrestrial requirements and observed terrestrial characteristics."
Eyton and Parkhurst measured the azimuths of 358 Carolina Bays in fourteen counties from Georgia to Virginia. They say: "Measuring the precise orientation of an ellipse where overlap occurs is difficult. Although we omitted bays where we thought the orientation was too indistinct, some subjectivity in the actual alignment certainly occurred. Relatively small sample sizes, particularly in counties with wide azimuthal fluctuations, also affect the results."
"The mean azimuths for the fourteen sample counties are plotted on Figure 5. They display radial alignment, but more significantly, they have an apparent focus in either southern Ohio or Indiana which indicates the possibility of a point source." The convergence of the lines in Ohio or Indiana could be due to drawing straight lines on a flat map. Later, we will see that great circle trajectories have a convergence point in Wisconsin.
In 2001, Zanner and Kuzila presented a paper announcing that Nebraska had geological structures similar to the Carolina Bays. The Nebraska Rainwater Basins were originally discovered using Digital Orthophoto Quadrangles, a technology that preceded LiDAR. The Nebraska Rainwater Basins are oriented from the northeast to the southwest, almost perpendicular to the orientation of the Carolina Bays. The discovery of the Nebraska Rainwater Basins made it possible to postulate that these elliptical features were made by secondary impacts of terrestrial ice ejected by an extraterrestrial impact on the Laurentide Ice Sheet.
The 2006 book titled "The Cycle of Cosmic Catastrophes" by Richard Firestone, Allen West, and Simon Warwick Smith proposes that a giant dustball comet crashed into the ice of Hudson Bay and sent icy debris hurtling through the air. Within minutes, the massive low-flying lumps crashed into the eastern seaboard exploding into fireballs and gouging out the Carolina Bays. The authors combined their own bay alignment research with that of Prouty, Johnson, Eyton and Parkhurst to produce compass headings for more than 1,000 large bays. Most of the lines meet in Wisconsin, west of Lake Michigan. Taking into consideration the rotation of the Earth, the convergence point in Wisconsin actually corresponds to one or two impacts in Lake Michigan. A critical review of this book in 2011 described the explanation of the comet impact and the ice boulder fireballs as defying the laws of physics. However, the convergence of the Carolina Bays in Wisconsin and the possible impact in Lake Michigan have some support.
In 2010, Michael Davias and Jeanette Gilbride made a presentation at the Geological Society of America with the title "Correlating an impact structure with the Carolina Bays". One of their illustrations showed an elliptical crater structure in Saginaw bay and a butterfly pattern made by Nebraska Rainwater Basins in the Midwest and Carolina Bays along the Atlantic Coast.
The abstract says: "We propose that the Carolina bays are depositional artifacts in the surface of a ~10 meter-thick sheet of distal ejecta, spread differentially from a cosmic impact. The lack of a correlated impact structure in North America is challenging, however. Using the alignments of 40 fields of Carolina bays in the East and the Mid-West, we generated great circle paths for visualization in Google Earth.
This yielded a fuzzy triangulation locus centered at 43.5°N, 89.5°W. Our analysis implies this triangulation would yield an erroneous impact location, offset to the west due to Earth rotation of 0.25 degrees of arc every clock minute of flight time. Adjustment of the crater eastward along the 43.5°N parallel should direct us towards the actual impact site. We examined geological depressions found along that transit, selecting the Saginaw area of Michigan." The 0.25 degrees per minute is derived from the fact that the Earth rotates 360 degrees in 24 hours and 1 hour has 60 minutes. We can also calculate that at latitude of 43.5° the Earth rotation of 0.25° corresponds to 20.1 kilometers in longitude.
In order to calculate the distance that the Earth rotates between the time that the ice boulders are launched by the extraterrestrial impact and when they land, we use ballistic equations to calculate the times of flight of the ejected ice boulders. Using distances from 1000 kilometers to 1,470 kilometers, we find that the flight of the projectiles varies from about 6 to 9 minutes. A projectile flight of about 8 minutes corresponds to offset in longitude of 160.8 kilometers eastward from the convergence point of the axes.
Using Google Earth, we can draw a line measuring 160 kilometers to the east of the convergence point determined by Davias. The end point, which would mark the site of an extraterrestrial impact, is in the middle of Lake Michigan, just as indicated by Firestone's book. Saginaw Bay, which was the site chosen by Davias as the impact point, is about 400 kilometers away from the convergence point, and would have required a 20-minute ballistic flight. The paper by Davias and Gilbride says that the Saginaw Bay area was selected heuristically.
This image of the Lake Huron bathymetry is marked to suggest that the impact at Saginaw Bay could have come from the southwest. The point of the black arrow is at the deepest point of Lake Huron, and it is remarkable that Saginaw Bay is aligned with the deepest point. The curvature of the bathymetry seems compatible with the shock waves of a projectile coming from the southwest. This was not the motivation why Davias and Gilbride chose Saginaw Bay as a potential impact location. On the contrary, they suggest that the extraterrestrial impact came from the northeast creating an oval shaped crater and a butterfly ejecta pattern.
In my own research, the majority of the lines intersect in Wisconsin, confirming the findings of Firestone and Davias. This makes it very likely that an extraterrestrial impact hit the Laurentide ice sheet that covered Lake Michigan. However, there are other intersection points, including some close to Saginaw Bay. For this reason, an extraterrestrial bombardment by multiple comet fragments cannot be excluded.
The extensions of the major axes of the Nebraska Rainwater Basins and the Carolina Bays seem to have several convergence points. It will be interesting to see how these intersections develop as new lines are added.
The choice of Saginaw Bay as an impact location has been severely criticized on the basis of gravimetric analysis. In addition, the origin of the Carolina Bays from ice ejected by an impact at Saginaw bay has been contested on the basis that the Laurentide Ice Sheet had retreated from the Saginaw Bay region well before 12,900 years ago or 11,100 radiocarbon years before the present.
Several authors have reported that Saginaw Bay was covered with ice at the onset of the Younger Dryas. A 1993 paper by Blewett, Winters and Rieck tested the Port Huron moraine and reported a radiocarbon age of 12,960 ± 350 yr BP from sediments immediately proximal to the northwestern part of the Inner Port Huron moraine in Michigan's Southern Peninsula. Based on this paper, it is very likely that the Laurentide Ice Sheet covered Saginaw Bay at the time of the onset of the Younger Dryas, so an extraterrestrial impact at that location would have launched pieces of ice.
Earlier, we saw the comment by Eyton and Parkhurst that measuring the precise orientation of ellipses that overlap is very difficult. Determining the dimensions of the bays is particularly challenging for bays that are overlaid by another bay, like the bay labeled B in this image. However, fitting ellipses to the Carolina Bays by the least squares method provides an objective way of determining the width and length of the bay, as well as its orientation.
We can digitize the Carolina Bays by recording latitude and longitude coordinates at multiple points along the rim using Google Earth. We are interested in measuring the flat portion of the bay just inside the rim. The sample points are at the margin where the colorized topography indicates a change in elevation. No samples are taken at the margin that is deformed due to the overlap.
The coordinates of the perimeter of the Carolina Bay are input into a program that fits an ellipse to the points. The program also calculates the azimuth. This open-source software is available on Github for everyone.
The azimuth provided by the software can be used to draw a great circle trajectory toward the Great Lakes using Google Earth. The extension of the major axes of these bays in Marlboro County, South Carolina pass very close to the convergence point determined by Davias and Gilbride.
The impact angles calculated from the width-to-length ratios, and the distance of the bays from the convergence point are used to calculate the characteristics of the trajectories. The ballistic equations indicate that the glacier ice boulder that made basin A was launched at a speed of 3.465 kilometers per second. It had a flight time of 7.63 minutes and reached a height of 257 kilometers above the surface of the Earth. The trajectory was a suborbital space flight in the vacuum of space. Basin B was launched at a speed of 3.532 kilometers per second and it had a flight time of 7.04 minutes. From the law of superposition, we know that basin B was emplaced first, and from the ballistic equations we know that basin B was overlaid by basin A 35 seconds later.
The glacier ice projectiles that made these basins measured approximately one fifth of the basin length. The impact that made basin A had energy equivalent to 15.3 megatons of TNT, and the impact that made basin B had energy equivalent to 9.9 megatons of TNT. Both of these impacts produced seismic vibrations exceeding magnitude 8.
In a previous analysis of these Carolina Bays in Marlboro County, before I developed the least squares ellipse fitting procedure, I had manually measured, and visually estimated, the width and length of bays A and B. Compared to the least squares method, the manual method underestimated the length of basin A by 26 meters, which is 1.8 percent.
The length of bay B measured manually is 6 meters less than calculated by the least squares method, but the width, which was just a guess because the perimeter is overlaid, was 22 meters less. This is a 3.1 percent error. The increase in these numbers also increases the energy estimate for the ice boulder bombardment in Marlboro County of South Carolina to more than 8 megatons per square kilometer. Such a heavy bombardment must have been accompanied by an extinction event and serious ecological damage in the area covered by the ejecta curtain.
Digitizing and fitting ellipses to Carolina Bays makes the process of measuring the bays more exact. Only five points are needed to fit an ellipse, so the ellipse fitting procedure and the measurements are not compromised when a part of the Carolina Bays is obscured by overlapping bays or degraded by erosion. This increase in precision is possible only because well-preserved Carolina Bays are elliptical conic sections that originated as inclined conical cavities, also called penetration funnels. An experimental model provides support for this mechanism.
