Saturday, April 1, 2017

Carolina Bays are Shock Liquefaction Impact Features

 















As i posted back in 2007 from my manuscript Paradigms Shift, the Carolina Bays are part of the evidence suite supporting the impact of a large comet onto the norther Ice Cap around 13,900 BP.  That they were identified by others as likely caused by ballistic ice from the Ice Cap is very welcome.  This is geology at its best.  That it has been ignored is irrelevant as that demands understanding the critical importance to human history of the Pleistocene nonconformity in the first instance.


Rather obviously you cannot accept the one without the other and that means understanding human history restarted after that event wiped the slate clean.  Cultural records say as much and plenty of other evidence abounds.  Yet old fashioned denial holds sway.


My contribution to all this has been to understand that the comet blow was targeted in order to induce a critical crustal movement that continues to play out today in order to eliminate the Northern Ice Cap.  That was the central purpose.  Ultimately it also flooded huge tracts of what is now the continental shelve, then hospitable for agriculture and opened up the whole northern hemisphere to agricultural development now well begun.  This represents a vast increase in usable land toward a potential human population of around 100 billion.

 .. 

Problem solved: Carolina Bays are shock liquefaction impact features from hypersonic ice boulders launched from the glacial ice sheet by a cosmic impact at the Younger Dryas
A. Zamora



The Tusk was absolutely thrilled to see the publication last week of a paper concerning Carolina Bays in the distinguished journal, Geomorphology. Other than a brief role for the Carolina bays in the early papers of the Comet Research Group, and a much longer series of Geological Society of America posters laboriously researched and determindly published by Michael Davias et. al, Zamora’s A Model for the Geomorphology of Bays is the only peer-reviewed and published ‘ET origin’ work on bays in the last two decades — and it is a doozy.

 http://cosmictusk.com/antonio-zamora-geomorphology-carolina-bays-shock-liquefaction-features-glacial-icebergs-launched-cosmic-impact-ice-sheet/

Zamora builds on the work of Willam Prouty and Melton and Schriver in the first half of the 20th century, with an assist from Eyton and Parkhurst in the 70’s, and finally Davias and Kimbel’s efforts in recent years. Each of the researchers maintained that the bays were formed at once by a barrage of material from the midwest. But, just as the early researchers ultimately decided, those around today also dismiss bays as the direct impacts of ET fragments of a comet or asteroid, and consider them to be the remnant features of secondary impacts from the ejecta and ballistic shockwaves of a northerly catastrophe. They are wise to do so.

The correct theory must account for ALL the easily observed, unique characteristics of bays. [See list of 16 from Eyton and Parkhurst here] The “wind and wave,” gradual formation, theories that continue to hold sway in classrooms, and publications from Ivestor and Brooks, fail miserably to account for all the observed phenomena. Zamora checks each off with ease. When time permits I hope to address them one by one.

Significantly, Zamora’s work is multidisciplinary and, like Davias, assisted by geometry as well as geology. Here is a sample:
Ellipses are mathematical conic sections formed by the intersection of a plane and a cone. The elliptical geomorphology of the Carolina Bays and the Nebraska Rainwater Basins can be explained if the bays originated from slanted conical cavities that were later remodeled into shallow depressions by geological processes. A width-to-length ratio of 0.58 corresponds to a cone inclined at 35° using the relationship sin(θ) = W/L. The proposed conical cavities could have been made by impacts of material ejected at approximately 35° in ballistic trajectories from the point of convergence in the Great Lakes Region. The small variations of the width-to-length ratio correspond to slightly different angles that are consistent with possible ballistic trajectories
The bay rims to Zamora are the result of a complex mathematical equation. They are the final surface expression of thousands of conical, inclined ballistic shock cones, each traveling with a giant ice fragment blown from the ice sheet in a nine-minute supersonic arc from the frigid north to the Carolina coast. (I will work on that sentence but you get the idea). These icebergs from space slammed into the supersaturated unconsolidated clayey sands of the coastal plain and left behind the shock “ripples” and “flaps” that we recognize today as bay rims. Zamora even provides an equation relating the perfection and ellipticity of bays to the degree of unconsolidated sediments encountered by the ice bullets:
The LiDAR images also reveal that some terrains do not have elliptical bays. Davias and Harris (2015) describe six archetype bay shapes that may be determined by the geological characteristics of the terrain. The thickness of the layer of unconsolidated material required to produce an elliptical bay can be estimated by the formula tan(θ) × L/2, where L is the length of the major axis and θ is the angle of inclination. A conical cavity inclined at 35° corresponding to a bay with a major axis of 400 m would require a layer of unconsolidated material with a depth of approximately 140 m.
That makes sense to me, and accounts for the “classes” of similar bays, an aspect unexplained by wind and water enthusiasts, but first investigated and catalogued by Davias.

In addition to the present journal publication, Zamora makes his case in detail in a recently published book available from Amazon: Killer Comet: What the Carolina Bays tell us. I am reading it now and will update this post accordingly.

On the shoulders of genius, Zamora has provided defensible and superior answers to the many questions provoked by the appearance and distribution of Carolina bays. The geological community will largely ignore this paper, of course, but some will take note. And there is always reason for hope as the class of geologists who reject recent catastrophic explanations out-of-hand continue their long march from the tenured defense of the known, to retirement, and finally to death. I note that in closing Zamora gives a shout-out to his editor, Professor Andrew J. Plater of the University of Liverpool, clearly an enlightened man, who tweets here as @GeomorphologyDr if you care to thank him.


January 22nd, 2017 | Tags: | Category: Carolina Bays, New Papers
 1. Introduction

The Carolina Bays are shallowelliptical depressions with raised rims that occur on the Atlantic Coastal Plain along the east coast of the United States. The geometrical elliptical shape of the bays and their particular
orientation first became apparent fromaerial photographic surveys. Because
the bays have very regular shapes that are very different from
other geological structures, Melton and Schriever (1933) suggested
that they had been created by a swarm of oblique meteorite impacts.
However, meteorite fragments are not common in the region where
the bays are located, and the alignment of the bays varies by latitude instead
of being parallel as would have been expected for impacts by extraterrestrial
objects. The lack of impact evidence led to hypotheses of
geological mechanisms that could have produced the bays, such as the
modification of karst-like depressions by the action of water and wind
(Johnson, 1942). In 1975, Eyton and Parkhurst proposed that the
Carolina Bays could have formed by air blasts from explosions of fragments
of a disintegrating comet. Dating studies of the bays have concluded
that the bays were formed over an extended period of time
during the Late Pleistocene starting approximately 140,000 years ago
(Brooks et al., 2010), thus precluding the possibility that all the bays
formed at the same time.
Zanner and Kuzila (2001) reported that Nebraska's Rainwater Basins,
which they characterized as eolian blowouts, had many characteristics
in commonwith the Carolina Bays, except that theywere oriented
from northeast to southwest instead of from northwest to southeast.
The Nebraska Rainwater Basins are not as well known as the Carolina
Bays but their elliptical shape is so similar that it is necessary to consider
that they formed contemporaneously with the Carolina Bays by the
same mechanisms. Firestone et al. (2007) proposed that an extraterrestrial
object exploding over North America 12,900 years ago contributed
to the megafaunal extinctions in North America and partially
destabilized the Laurentide Ice Sheet and the thermohaline circulation
in the northern Atlantic, thus triggering the Younger Dryas cooling
event. The date of the event has been updated to 12,800 cal. BP by
Kennett et al. (2015). In a subsequent paperwith images of the Carolina
Bays and the Nebraska Rainwater Basins, Firestone (2009) stated that
the strikingly regular orientation of the bays was consistent with their
formation by a shockwave coming from the Great Lakes. Firestone
(2009), Firestone et al. (2010) also reported that impact material was
found throughout the Carolina Bay sediments whereas these markers
were found only in a thin layer elsewhere at the Younger Dryas Boundary;
this can be interpreted as an indication that the bays are impact related.
Pinter et al. (2011) wrote a “requiem” paper about the Younger
Dryas Impact Hypothesis concluding that the evidence for an extraterrestrial
impact could not be corroborated and that terrestrial mechanisms
could account for the geological formations.

2. New impact evidence

The question of whether an extraterrestrial impact occurred at the onset of the Younger Dryas has been a contentious issue because the microspherules, nanodiamonds and other materials that Firestone proposed as indicators of an impact have not been recognized as definitive evidence of an impact. Someof the acceptedmarkers of an extraterrestrial event are impact craters with raised rims, meteorite fragments, shocked minerals with planar deformation features caused by the high pressure of a hyperspeed impact, and siderophile elements, such as iridium, that are more common in extraterrestrial objects than in the minerals found in the Earth. Nevertheless, additional reports of
microspherules attributed to an extraterrestrial impact at the Younger Dryas Boundary have been reported (Israde-Alcántara et al., 2012; LeCompte et al., 2012).

The support for an extraterrestrial impact was strengthened when
analysis of the Greenland Ice Sheet Project 2 (GISP2) ice core by
Petaev et al. (2013) found a large platinum anomaly at the Younger
Dryas Boundary. The increased platinum was not accompanied by a
prominent iridium anomaly, and the ratio of platinum to iridium
exceeded those of known terrestrial and extraterrestrial materials.
Petaev and his colleagues concluded that the results hinted at an extraterrestrial
source of platinum, possibly from an iron meteorite of low
iridiumcontent thatwould be unlikely to result in the airburst proposed
by Firestone. An iron meteorite could have survived the passage
through the atmosphere, making it possible to consider that material
ejected from the primary impact site would have produced secondary
impacts.
3. Greater availability of good quality imagery
The study of the shapes of the Carolina Bays was limited to photographic
aerial surveys prior to the development of LiDAR. The Carolina
Bays are obscured by a patchwork of farmed fields and vegetation in aerial
and satellite images. Digital ElevationMaps (DEMs) using LiDAR-derived
data accentuate the visual representation of these shallow basins.
A survey of Carolina Bays by Davias and Gilbride (2011) used a wide
range of resources, including 1/9 arc-second elevation data from the
USGS Seamless Server, NOAA Digital Coast, South Carolina Department
of Natural Resources (DNR), Nebraska DNR, and Virginia's College of
William and Mary. The data was processed with the Global Mapper
commercial GIS program to visualize the terrain as HSV-shaded images
saved as KeyholeMarkup Language (KML) tiled data files. The KML files
can be directly imported into Google Earth to align the images on a virtual
globe from which it is possible to capture geospatial metrics. The
Carolina Bay survey now contains data for approximately 45,000 bays
(Davias and Harris, 2015).
LiDAR has revealed very clear images of the bays without interference
from vegetation, and it is evident that the terrain consisting of unconsolidated
material is completely covered with bays, and that many
bays overlap while maintaining their elliptical shape. The only places
without bays are the streambeds where water erosion has washed
away evidence of their existence (Fig. 1).
4. Bay orientations
Early studies of the Carolina Bays using aerial images revealed that
the bay orientations differ by latitude. Johnson (1942) used photographs
from Fairchild Aerial Surveys, Inc., the U.S. Department of Agriculture,
the Agricultural Adjustment Administration and the U.S.
Geological Survey. The scarcity and inaccuracy of topographic maps
for North Carolina, South Carolina and Georgia constrained Johnson to
select only 381 bays that could be used to determine axial direction.
Johnson found that the northernmost bays were oriented primarily toward
the northwest, whereas the southernmost bays were oriented
more toward the north. A separate study by Eyton and Parkhurst
(1975) of 358 bays in Virginia, North Carolina, South Carolina and
Georgia concluded that the bays display radial alignmentwith an apparent
focus in either southern Ohio or Indiana.
Davias and Gilbride (2010, 2011) established a survey of thousands
of Carolina Bays and Nebraska Rainwater Basins using LiDAR data and
Google Earth. Using great circle trajectories adjusted for the Coriolis Effect,
Davias and Gilbride identified Saginaw Bay in Michigan as the intersection
point of the projections of the major axes of the bays. In a
subsequent paper, Davias and Harris (2015) provided a trigonometric
equation that can predict the azimuthal orientation of 45,000 bays in
Nebraska and the East Coast of the USA based only on their geographical
coordinates. Davias and Harris (2015) also noted that the equidistance
between the Carolina Bays and the Nebraska Rainwater Basins from
the proposed impact point in Saginaw Bay suggests that an extraterrestrial
impact at a low angle created an oval-shaped crater and a butterfly
ejecta pattern. This butterfly pattern could merely be a peculiarity due
to the lack of terrain suitable for the formation of elliptical bays between
Nebraska and the East Coast.
Before the availability of Google Earth, researchers had not been able
to find a point of convergence for the Carolina Bays because they
worked with flat maps, and they did not take into consideration the
Coriolis Effect corresponding to the time of flight of the ejecta. The
axial orientation of the Nebraska Rainwater Basins was also important
for determining the point of convergence.
5. Bay geometry
Aerial photographs from the 20th century showed the remarkable
elliptical symmetry of many Carolina Bays, but interference from vegetation
and the patchwork of farmed fields made it difficult to appreciate
the extent of this regularity. Consequently, the elliptical shapes of the
bays were assumed to be atypical features that formed fortuitously by
variable lacustrine and eolian mechanisms (Johnson, 1942).
The consistent shape and orientation of the Carolina Bays was what
first attracted the attention of geologists. However, the description of
the bays in the published literature seems to be biased according to
the hypothesis of formation favored by the authors. Proponents of impact
hypotheses (Melton and Schriever, 1933; Prouty, 1952) generally
describe the bays as elliptical; they provide graphs of the ellipticity of
the bays and relate the shape of the bays to the angle of impact based
on conic sections. Ellipticity is defined as the lengthminus thewidth, divided
by the length. Proponents of eolian and lacustrine processes, on
the other hand, characterize the Carolina Bays as oval and do not attribute
significance to their consistent shape (Johnson, 1942) or they do
not mention the geometric shape of the bays at all (Brooks et al.,
2010). Zanner and Kuzila (2001) described the remarkable similarity
of the Nebraska Rainwater Basins to the Carolina Bays, and characterized
the Nebraska features as oval shaped blowouts

This dichotomy in the description of the bays brings up the question
ofwhether the Carolina Bays and theNebraska Rainwater Basins are just
ovals with indeterminate curvature or whether they are true ellipses in
the mathematical sense. Fortunately, this question can be settled by
comparing the geometry of the bays to mathematical ellipses.
The method for testingwhether a Carolina Bay is elliptical consists of
three steps: 1) measure the width and the length of the proposed
Carolina Bay, 2) create an ellipse with the same width-to-length ratio
as the target bay, and 3) scale and rotate the ellipse to try to match
the bay as precisely as possible. For this testing procedure, the rims
are considered to be external to the presumed conical cavity corresponding
to the bay, and they are not included in the measurement of
the bay or the fitting of the ellipse. The matching depends on the size,
placement and orientation of the ellipse. The goodness of fit can be
made visually or by quantitative measures such as least squares fitting
once the margins of the bay have been identified accurately.
Problems related to measuring the bays and fitting the ellipses arise
from irregularities in the shapes of the bays due to distortions caused
by bay overlaps, geological surface deformations, water erosion and encroachment
of the bays by eolian deposits. The determination of the bay
boundaries can be subject to interpretation, as pointed out by Johnson
(1942). Even under ideal conditions, the identification of craters is difficult.
A project to map Moon craters by overlaying them with circles
found 10–35% dispersion among experts in the number of craters
found, even though the experts were more consistent than volunteers
in identifying craters (Robbins et al., 2014). The fitting of ellipses for
the Carolina Bays is even more difficult because it requires the extra
step of determining the axial orientation. In spite of this, it is possible
to conclude that the prototypical shape of the Carolina Bays is elliptical.
An examination of a sample of Carolina Bays and Nebraska Rainwater
Basins with clearly defined rims showed that they have average widthto-
length ratios of 0.58 ± 0.05, and that the aspect ratios of the bays in
the Carolinas and Nebraska are statistically indistinguishable (Zamora,
2015). The width-to-length ratio of 0.58 corresponds to the average
ellipticity reported by Prouty (1952) for large bays in Marion and
Darlington counties, South Carolina. Each bay can be precisely fitted
with an ellipse whose ratio of minor to major axis corresponds to the dimensions
of the bay as illustrated in Figs. 2 and 3. The large bays are much
bigger than Meteor Crater in Arizona, which has a diameter of 1.2 km.
Ellipses are mathematical conic sections formed by the intersection
of a plane and a cone. The elliptical geomorphology of the Carolina
Bays and the Nebraska Rainwater Basins can be explained if the bays
originated from slanted conical cavities that were later remodeled into
shallow depressions by geological processes. A width-to-length ratio
of 0.58 corresponds to a cone inclined at 35° using the relationship
sin(θ) = W/L. The proposed conical cavities could have been made by
impacts of material ejected at approximately 35° in ballistic trajectories
fromthe point of convergence in the Great Lakes Region. The small variations
of the width-to-length ratio correspond to slightly different angles
that are consistent with possible ballistic trajectories.
The LiDAR images also reveal that some terrains do not have elliptical
bays. Davias and Harris (2015) describe six archetype bay shapes
that may be determined by the geological characteristics of the terrain.
The thickness of the layer of unconsolidated material required to produce
an elliptical bay can be estimated by the formula tan(θ) × L/2,
where L is the length of the major axis and θ is the angle of inclination.
A conical cavity inclined at 35° corresponding to a baywith a major axis
of 400mwould require a layer of unconsolidatedmaterialwith a depth
of approximately 140 m.
In general, bays that are not elliptical today may have started as elliptical
features that were modified after their formation by erosion or
ground movement. Fig. 2 shows many small bays in North Carolina
that are on the verge of disappearing due to erosion. The small bays
that look like dimples are generally on farmland that gets plowed
every year. This ground will eventually be leveled by the frequent
human activities of tilling and irrigating the soil, bioturbation by crops
and fauna, and by natural environmental erosive processes of rainfall
andwind. Fig. 3 shows Nebraska Rainwater Basins thatwere recognized
as analogous to the Carolina Bays by Zanner and Kuzila (2001). The
main geological difference noted by these researchers was that cores
from Nebraska indicated a sandy landscape buried by loess. If the
Carolina Bays and Nebraska Rainwater Basins formed contemporaneously,
the lack of small bays and the extensive modification of the
large bays in Nebraska indicate that the Nebraska featureswere subjected
tomore vigorous erosive processes than the Carolina Bays. The preservation
of the Carolina Bays may be due in part to highly permeable
ground that allows water to pass quickly below the surface and then
flows through underground aquifers. The Nebraska Rainwater Basins
are on abandoned Platte River fluvial sand situated on topologically irregular
terrain that is more likely to channel water along the surface
thus causing greater erosion. Non-elliptical bays are likely to occur in
terrain that was unsuitable for the formation of conical cavities due to
insufficient depth of unconsolidated sediment or because the water
table was too deep for the ground to be liquefied. Fig. 4 shows Carolina
Bays on the Delmarva Peninsula that are approximately circular, as
would be expected for impacts on a surface with insufficient depth of
unconsolidated material.
6. The Glacier Ice Impact Hypothesis
The Carolina Bays have no evidence of meteorites, petrographic
shock metamorphism or enrichment by siderophile elements, so they
Fig. 2. Carolina Bays fitted with ellipses. (Lat. 34.833, Lon. −79.225) The center of the
image is 4 km northwest of Red Springs, North Carolina. Small bays with lengths

were definitely not formed by impacts of extraterrestrial objects. However,
the bays have raised rims,which is a characteristic of impacts. Unlike
karst processes that produce cavities by dissolution, impact
cratering displaces material laterally by horizontal compressive forces
and ejects debris ballistically to produce stratigraphically uplifted rims
around the cavity (Melosh, 1989). The objective of the Glacier Ice Impact
Hypothesis is to examine the characteristics of the Carolina Bays
and Nebraska Rainwater Basins to determine whether these geomorphological
features could have been created by secondary impacts
fromterrestrialmaterial, such as glacier ice, ejected by an extraterrestrial
impact.
The Laurentide Ice Sheet covered the convergence point determined
by Davias and Harris (2015) in SaginawBaywith a thickness of approximately
1500 to 2000mof ice during the Pleistocene (Dyke et al., 2002).
An impact by a meteorite at this location would have ejected chunks of
ice in ballistic trajectories, and the heat of the impactwould havemelted
some ice to producewater and steam. TheGlacier Ice Impact Hypothesis
describes four processes that must have occurred in a specific sequence
for the creation of the Carolina Bays.
6.1. Extraterrestrial impact ejects glacier ice boulders in ballistic trajectories
Experiments of high-speed impacts on ice sheets using NASA”s
Ames Vertical Gun demonstrate that ice shatters when a projectile
hits it. Pieces of ice are ejected radiating from the impact site in ballistic
trajectories and the icy layer reduces the extent of subsurface damage
(Stickle and Schultz, 2012). If the Carolina Bayswere created by secondary
impacts of glacier ice ejected by an extraterrestrial impact on the
Laurentide sheet, the velocity needed to launch the ice projectiles can
be calculated using the ballistic equation D = (v2/g)sin(2θ), where g
is the acceleration of gravity. An ice boulder ejected at an angle θ of
35° from Michigan to the South Carolina seashore would require a
launch speed v of approximately 3.6 km/s to cover the distance D of
1220 km.
Substituting distances between 1000 and 1500 km, and angles between
35 and 45° in the formula yields launch speeds of the ejected glacier
ice boulders in the range of 3 to 4 kmper second. The timeof flight T
and the maximum height H of the trajectories are given by the equations
T = (2v/g)sin(θ) and H = v2sin2(θ)/2 g. Using the same range of
distances and launch angles, the times of flightwould vary fromapproximately
6 to 9 min, and all the ballistic trajectories would be suborbital
space flightswithmaximumheights from150 to 370 km above the surface
of the Earth. The atmosphere only extends to 100 km above sea
level, so a substantial portion of the trajectory of the ice boulders
would have been in the vacuum of space. Some of the projectiles
would have broken up during re-entry and produced multiple impacts.
Since some Carolina Bays have been found as far south as the Georgia-
Florida border, the distal ejecta of the extraterrestrial impact covered
approximately an area with a radius of 1500 km from the impact
point. The bombardment by the ejected ice boulders lasted for about
9 min after the extraterrestrial impact.
Kennett et al. (2015) and Firestone et al. (2007), Firestone (2009),
Firestone et al. (2010) have reported evidence of widespread biomass
burning and the emplacement of a black mat at the Younger Dryas
boundary. Firestone et al. (2007) stated that an impact by single ormultiple
objects could have created fireballs thatwould have ignited a forest
in seconds. Could the extraterrestrial impact being considered here
have caused a major burning event? A comet at a speed of 50 km/s
would traverse the atmosphere vertically in 2 s generating a very intense
flash. An asteroid at a speed of 17 km/s would generate a somewhat
less intense flash lasting approximately 6 s. An oblique approach
by the extraterrestrial projectile would substantially increase the time
of intense radiation capable of carbonizing organic material. Any fauna
in the line of sight of the incandescent projectile would be burned or
disabled, contributing to an extinction event. Some of the fires started
by the passage of the projectile would be extinguished by the air blast
of its shockwave. The biomass burning would have occurred during
the passage of the projectile through the atmosphere and its initial contactwith
the Laurentide ice sheet. The greatest charringwould be under
the path of the fireball.
How could the ejected ice boulders survive ablation during their
transit? A numerical model indicates that an impact by a kilometersize
projectile would have moved the atmosphere, as well as the mass
of ejecta to the rarefied upper atmosphere where even fine ejecta
movemore or less ballistically (Shuvalov and Dypvik, 2013). The ballistic
trajectories of the ice boulderswere all suborbital space flightswith a
significant portion of the flight in the vacuum of space where ice would
not be subject to ablation. However, during re-entry, the ice boulders
would have experienced ablation, collisions, fragmentation and atmospheric
drag causing the smaller projectiles to impact at more vertical
angles than the larger projectiles (Melosh, 1989). Considering that the
Carolina Bays were produced by a saturation bombardment of glacier
ice projectiles, the close proximity of the projectiles as they re-entered
the atmosphere could have decreased ablation for the projectiles that
traveled behind others. Drafting or slipstreaming occurs when moving
objects align in a close group thereby reducing the overall effect of
drag by exploiting the lead object's slipstream. The effect of atmospheric
drag was reported byMelton and Schriever (1933) and Prouty (1952) in
their graphs plotting ellipticity vs. bay length.
Why did the ice boulders travel such long distances? There are three
reasons: 1) ice has about one third the density of rock, 2) the ballistic
trajectories carried the ice projectiles above the atmosphere where
there is no atmospheric drag, and 3) the speed of the ice ejecta was
boosted by a rapidly expanding plume of steamfromthe extraterrestrial
impact site. Using the equation for kinetic energy, we can calculate that
a rockwith three times the density of icewould only have about 0.6 the
velocity of ice, and the denser rock at the lower speed could only travel
one third as far as the ice. In addition, rocky ejecta would travel within
the atmosphere where friction would reduce the speed further.
6.2. Secondary impacts liquefy unconsolidated soil
The size of the glacier ice projectiles can be determined from their
speed and the size of the bays using yield-scaling laws that correlate energy
with crater size (Melosh, 1989). In addition, the energy of the extraterrestrial
impact can be estimated by adding the energy required
to form all the bays or by multiplying the energy of a typical bay by
Fig. 4. Bays near Barclay,MDon the Delmarva peninsula. (Lat. 39.15933, Lon.−75.85541)
The circular shape of the baysmay be due to insufficient depth of unconsolidated material
that prevented the formation of conical cavities. Circular bays are also found further south
in the peninsula near Mappsville, VA.

500,000, which is the estimated number of bays reported in the literature
(Prouty, 1952).
The equations fromMelosh calculate that a craterwith a diameter of
1 km, which corresponds to a Carolina Bay of intermediate size, can be
made by a spherical ice boulder with a diameter of 180 m traveling at
a speed of 3 km/s when impacting sandy terrain at an angle of 45°.
The energy of the impact would be approximately 1.27 × 1016 J or
3.03 megatons of TNT explosive force. Such an impact would be the
equivalent of a magnitude 7.54 earthquake. A smaller bay with a diameter
of 220 m would correspond to an impact made by a 28-m ice
boulder with energy of 13 kt of TNT, which is about the same energy
as a 6.0 magnitude earthquake. By comparison, the bomb dropped on
Hiroshima had an approximate yield of 15 kt of TNT. The LiDAR images
of adjacent and overlapping bays, such as Fig. 1, indicate that the Carolina
Bays could have been created by a powerful saturation bombardment of
glacier ice chunks that would have killed fauna and destroyed their habitat.
Soil liquefaction is a phenomenon in which saturated soil loses
strength in response to applied stress causing it to behave like a liquid.
Liquefaction is frequently associated with earthquakes (Youd et al.,
2001). The earthquake in Christchurch, New Zealand in February 2011
had a magnitude of 6.3 and produced seismic shock waves that shook
the ground and turned sandy soils into quicksand that swallowed cars
and displaced roads. Even smaller aftershocks of magnitude 5.7 liquefied
the soil. In general, seismic events of magnitude 6.0 and higher
cause sufficient vibration to liquefy saturated soil.
In North Carolina, the water table is within 1.5 m below the sandy
soil where the bays are found (Eimers et al., 2001). This ground would
have been liquefied by the barrage of ice projectiles with energies of
13 kt to 3 MT of TNT. Even if the initial impacts had encountered solid
unconsolidated ground, the impacts occurring shortly thereafter
would have struck soil liquefied by the seismic vibrations of the preceding
impacts.
The characteristics of the extraterrestrial object can be calculated by
considering that if there are 500,000 Carolina Bays and each one was
formed by an energy of 1.27 × 1016 J, then the total energy of the impacts
was approximately 6.35 × 1021 J. This total energy provides a
rough estimate of the kinetic energy transferred to the ejecta by the extraterrestrial
impact. Additional energy would have been converted to
heat, seismic energy and fracturing of the target and projectile. The kinetic
energy of 6.35 × 1021 J corresponds to an asteroid with a diameter
of approximately 3 km traveling at a speed of 17 km/s.
6.3. Oblique impacts on liquefied soil create slanted conical cavities
Conical impact cavities have not received much attention in the scientific
literature because they are usually transient and disappear in
fractions of a second. Conical shock waves of objects passing through a
fluid are usually visualized using schlieren photography or high-speed
photography. Cavities made by the conical shock waves of a projectile
can remain stable for a relatively long time if the target material is viscous
and not elastic (Zamora, 2015). If the target material is too hard,
the projectile will shatter and release its energy explosively sending a
hemispherical shock wave that creates a typical bowl-shaped crater. If
the material is too elastic, the conical cavitymade by the passing projectile
will immediately collapse leaving only a tubular trail. Conical cavities
can only be made when a projectile travels through a viscous
medium without disintegrating and the medium has a consistency
thick enough to retain the shape of the shock wave. The projectile
loses energy as it parts the viscous medium, and it eventually stops at
the vertex of a conical cavity. The creation of a conical cavity is a plastic
deformation that can be partially reversed by the elastic properties of
the medium or by the force of gravity.
The formation of a conical cavity on a viscous target creates a new
surface, which is the interior of the cone. This new surface is exposed
to light, but the subsoil beneath the new surface remains unexposed
to light when the cavity is formed and when the depth of the cavity is
subsequently reduced by viscous relaxation. The penetration of the liquefied
soil by the projectile does not create turbulent mixing thatwould
expose any of the subsoil to light during the formation of the conical
cavity. This means that dating the subsoil by Optically Stimulated Luminescence
(OSL),which determines the time elapsed since some mineral
crystals were exposed to light, can only provide the date of the terrain,
but not the date of formation of the conical cavity.
Would it be possible to use OSL to date the ejecta that formed the
bays? OSL works for gradualistic depositional processes for which the
dose of radiation can be ascertained for the terrainwhere the test material
is collected. The luminescence signal increases in proportion to the
time thematerial is buried, and it is reset by exposure to sunlight or intense
heat (N150 °C) for an extended period of time (USGS, 2016). The
ejecta from the extraterrestrial impact on the Laurentide Ice Sheet
would have been mostly ice. Ice boulders ejected from the bottom of
the glacier close to the glacial bed could have had significant amounts
of quartz grains or other material datable by OSL, but ice chunks ejected
from the upper layers of the one- to two-kilometer thick glacier would
consist mostly of ice. Let us suppose that the ejected glacier ice chunks
were exposed to sunlight during their suborbital space flights. Would
sunlight be able to penetrate through 20 m or more of ice to reset the
luminescence signal of the imbeddedmineral crystals? Probably not because
the transmission of light is reduced substantially even by a few
centimeters of ice (Little et al., 1972). The imbedded crystals would
also be undatable by OSL if the extraterrestrial impact occurred at
night and the ice boulders traveled in darkness. After the ice melted following
the creation of the conical cavities by the secondary impacts,
where would the mineral crystals imbedded within the ice end up?
Most likely, the mineral particles fromthe meltwater of the glacier projectiles
would disperse at the apex of the conical cavities in the target
terrain, and theywould quickly be covered up during viscous relaxation
making it impossible to isolate them or date them. Large clasts carried
within the glacier chunks might still be retrievable from deep within
the bays, but their dateswould not be able to confirm the timeof formation
of the Carolina Bays.
The shallow elliptical Carolina Bays have not been successfully explained
as impacts by projectiles striking the soil at grazing angles
(Johnson, 1942). However, if seismic shock waves from the impacts liquefy
the soil, it is possible to consider that oblique impacts on the liquefied
soil can create inclined conical cavities that are remodeled into
elliptical bays. The glacier ice boulders ejected from the Laurentide Ice
Sheet by themeteorite impact would have traveled in ballistic trajectories.
The launch angles would be approximately the same as the impact
angles. Taking into consideration that thewidth-to-length ratio of an ellipse
is the sine of the impact angle and that the Carolina Bays have
width-to-length ratios of 0.58 ± 0.05, we can deduce that the impact
angles of the ice projectiles would have had an inclination between 32
and 39°. These oblique impacts would have created slanted conical cavities
on liquefied soil.
Ice is brittle and fractures easily upon impact (Schulson, 1999). Glacier
ice projectiles with speed of 3 to 4 km/s crashing upon dense solid
ground or rocky terrainwould have shattered and thenmelted without
leaving any lasting evidence. However, the chunks of glacier ice that
survived atmospheric re-entrywould have had enough energy to liquefy
unconsolidated soil close to the water table and sufficient structural
integrity to create conical cavities on liquefied soil.
6.4. Viscous relaxation converts conical cavities into shallow elliptical bays
Extraterrestrial impact sites usually have a lens of brecciated and
molten material at the bottom of the crater. One of the arguments
used against the impact origin of the Carolina Bays is that the stratigraphy
beneath the bays is not distorted (Preston and Brown, 1964; Thom,
1970). However, impacts by chunks of glacier ice at speeds of 3 to
4 km/s on liquefied ground are not explosive events like those produced
by hypervelocity impacts. A projectile traveling through a viscous

medium is slowed down in proportion to its cross-sectional area and
drag coefficient. Ablation during transit reduces the projectile mass,
which also slows down the projectile (Melosh, 1989). Projectiles
impacting a viscous surface penetrate themediumand part it in a plastic
deformation that can be partially reversed by viscous relaxation.
Viscous relaxation is a deformation process driven by gravity that
tends to smooth out geological features by making hills less prominent
and valleys less deep (Melosh, 1989). The process is generally slow, but
it can be speeded up by reducing friction within the medium. For saturated
soil, this can be accomplished by vibrations that promote liquefaction.
A cavity created by an impact in a viscous surface is filled by flow of
the material surrounding the deepest part of the cavity. Pressure increases
with depth and this creates a velocity gradient that promotes
faster centripetal lateral flow at the bottom of a cavity. Viscous relaxation
fills an impact cavity in the reverse order in which it was created,
starting from the bottom up and restoring the original stratigraphy
layer by layer until friction stops the centripetal flow of material and
only a shallow bay remains.
7. Experimental impact model
The eolian and lacustrine hypotheses for the formation of the
Carolina Bays cannot be tested meaningfully. There is no way of verifying
how the wind was blowing when the bays were created. Some authors
state that the bays are aligned with the prevailing wind (Raisz,
1934; Melosh, 2011), while others claim that the bays are elongated
perpendicular to the wind direction (Zanner and Kuzila, 2001; Brooks
et al., 2010). No weather phenomenon has been confirmed as being capable
of forming elliptical bays, but the eolian hypotheses only consider
the prevailing winds rather than whirlwinds, tornadoes or hurricanes
with variable wind conditions. Furthermore, there is no known eolian
or lacustrine mechanism that can consistently create shallow elliptical
features with the 0.58 width-to-length ratios observed for the Carolina
Bays and Nebraska Rainwater Basins. It is not possible to design an experiment
to test the terrestrial hypotheses without knowing how the
specific aspect ratios are achieved and maintained over a large geographical
area.
By contrast, the Glacier Ice Impact Hypothesis proposes fourmechanisms
that can be tested with a combination of mathematical and experimental
tools. Ballistic equations, scaling laws relating crater size to
impact energy, geometrical analysis and statistical analysis provide a
mathematical foundation for explaining the shape of the bays and
their origin from secondary impacts of glacier ice ejected from the
Laurentide Ice Sheet that covered Michigan. From geometry, we know
that ellipses with the aspect ratios of the Carolina Bays correspond to
conic sections inclined at 35°. It is relatively easy to design experiments
to study the formation of slanted conical cavities by oblique impacts of
ice projectiles and the process of viscous relaxation. The results of
these physical models provide insights about the geomorphology of
the Carolina Bays.
The following images show some experiments conducted on a mixture
of equal amounts of pottery clay and sand mixed with enough
water to have the consistency of bricklayer's mortar. A thin layer of colored
sand on the surface enhances visualization. A slingshotwas used to
fire the ice projectiles that made the impact cavities.
Fig. 5 shows inclined conical cavities made by oblique impacts. The
ice projectiles part the soil and stop at the apex of the conical cavity.
The penetration of the surface by the projectile creates flanges around
the cavity and pushes some material in the direction of travel.
Viscous relaxation reduces the depth of the inclined conical cavities
and transforms their flanges into overturned flaps that produce raised
rims around the shallow elliptical depressions (Fig. 6). Shaking the experimental
container speeds up viscous relaxation. After the ice melts,
there is no trace of the projectile. The same would be expected for the
glacier ice impacts that created the Carolina Bays.No trace of the projectilewould
remain in the Carolina Bays, except for someclasts that might
have been carried within the glacier ice. It is not known to what depth
the extraterrestrial projectile penetrated the glacier, but the projectile
would have had to go through the supraglacial and englacial segments
to reach the glacial bed in order to bring up clasts. This is something
that could be verified by geological exploration of the bays, although
not every bay would have such clasts. It is worth noting that the raised
rims are overturned flaps with inverted stratigraphy. Finding glacier
clasts within the bays or inverted stratigraphy in the rims would provide
verification of the Glacier Ice Impact Hypothesis.
Carolina Bays that overlap without affecting the shape of adjacent
bays are common. Two examples of bays that overlap can be seen in
Fig. 2. The eolian and lacustrine gyroscopic theories that have been proposed
for the formation of the Carolina Bays fail to predict the aspect ratios
of the bays, their orientations, and the creation of overlapping bays
(Melton, 1956). Impact experiments provide an explanation of how the
overlapping bays with similar aspect ratios can be created.
Fig. 7 demonstrates that impacts on liquefied ground can create conical
cavities adjacent to previous impacts without affecting the shape of
the previous bays. The aspect ratio of the resulting bay is determined by
the angle of impact.
Viscous relaxation of adjacent conical cavities on liquefied soil produces
overlapping bays (Fig. 8). Bay formation follows the principle of
superposition. A bay that overlaps another one was created later in
time. This makes it possible to determine the relative time of emplacement
of overlapping Carolina Bays.
In addition to the experiments illustrated here, the physical model
can be used to demonstrate that viscous relaxation, which decreases
the depth of an impact cavity by centripetal flow from the bottom up,
Fig. 5. Impacts by ice projectiles create conical cavities on a viscous surface.
Fig. 6. Viscous relaxation converts conical cavities into shallow bays with raised rims

restores the stratigraphy and prevents exposure to light of the soil beneath
the new conical surface created by the impact (Zamora, 2015).
These experiments are important because they provide information
about why the subsoil of the Carolina Bays appears undisturbed, and
why the dates of the bays are so diverse. The conical cavities are formed
by a plastic deformation that prevents light frompenetrating below the
surface of the new conical cavity thereby making OSL dating inapplicable.
OSL has been very successful for dating sedimentary processes, but
its use for dating material that may not have been reset by sunlight at
the time of formation of the Carolina Bays would be inappropriate. Carbon-
14 dating of the Carolina Bays has also been difficult due to the vertical
transport of carbon in sedimentary sequences (Kennett et al.,
2015). Analysis of charcoal and carbon spherules found within the sediments
of some bays have unusual radiocarbon dates that are inconsistent
with the age inferred by their stratigraphy and suggest that the
spherules are enriched in 14C (Firestone, 2009).
Can these experiments scale to the kilometer-size proportions of the
Carolina Bays? One advantage of physical models over computer
hydrocode simulations is that they integrate all the material interactions
of the system being tested. Small-scale physical models were
used by Stickle and Schultz (2012) to study impacts on ice, and Prouty
(1952) used a high-powered rifle to test the creation of shallow elliptical
cavities. Itwould be possible to design impact experiments tomodel
more closely the scenario proposed by the Glacier Ice Impact Hypothesis
by using soil samples fromthe Atlantic Seaboard on a shaking table that
promotes liquefaction. However, it is reasonable to expect that the experiments
presented here will scale up as the projectile size increases,
although certain attributes of the impact structures, such as rim width
relative to cavity size,will be different. The physicalmodelsmay provide
the fundamental parameters for developing computational models to
simulate multi-kiloton impacts.
8. Conclusion
The radial orientation of the Carolina Bays and Nebraska Rainwater
Basins toward a convergence point in Michigan (Davias and Harris,
2015) and the elliptical shapes of the bayswith specificwidth-to-length
ratios can be better explained by impact mechanisms than by terrestrial
wind andwater processes. The Glacier Ice Impact Hypothesis proposes a
sequence of four mechanisms that could have produced the Carolina
Bays by secondary impacts of glacier ice ejected from a primary extraterrestrial
impact on the Laurentide Ice Sheet. The hypothesis has
been supplemented with an experimental model demonstrating that
oblique impacts on viscous surfaces can reproducibly create inclined
conical cavities that are remodeled into shallow elliptical depressions
by viscous relaxation. This makes it possible to model the Carolina
Bays and Nebraska Rainwater Basins as conic sections whose widthto-
length ratio can be explained by the angle of impact. Unlike the eolian
and lacustrine hypotheses of bay formation that cannot be tested,
the impact hypothesis uses mathematics and a physical model that
can be used to demonstrate stratigraphic restoration by viscous relaxation
and the remodeling of conical impact cavities on viscous media.
The great diversity of dates obtained by Optically Stimulated Luminescence
(OSL) has been one of the greatest barriers for the acceptance
of an impact hypothesis. The use of OSL has assumed that the subsurface
of the Carolina Bays was exposed to light at the time of bay formation,
but the experimental model shows that impacts on viscous surfaces
are plastic deformations that do not expose the subsurface to light.
Therefore, OSL can only determine the date of the terrain, but not the
date of formation of the bays. If all the Carolina Bays and Nebraska Rainwater
Basins formed contemporaneously, it will be necessary to find a
different way of dating them.
The Glacier Ice Impact Hypothesis explains all the features of the
Carolina Bays and Nebraska Rainwater Basins, including their elliptical
shape, radial orientation, raised rims, undisturbed stratigraphy, absence
of shock metamorphism, overlapping bays, and the occurrence of bays
only in unconsolidated ground. In addition, the Glacier Ice Impact Hypothesis
predicts that the raised rims of the Carolina Bays will have
inverted stratigraphy characteristic of impacts, and that clasts carried
by the glacier ice projectiles might be found at the bottom of some
bays where the ice boulders stopped.
If the Carolina Bays were indeed made by impacts of ejected glacier
ice, the great surface density of the bays indicates that theywere created
by a catastrophic saturation bombingwith impacts of 13 kt to 3MT that
would have caused a mass extinction in an area with a radius of
1500 km from the extraterrestrial impact in Michigan. This paper has
considered mainly the ice boulders ejected by an extraterrestrial impact
on the Laurentide Ice Sheet during the Pleistocene, but the impact
would also have ejectedwater and produced steam. Taking into consideration
the thermodynamic properties of water, any liquid water
ejected above the atmosphere would have transformed into a fog of
ice crystals that would have blocked the light of the sun (Zamora,
2015). Thus, the time of formation of the Carolina Bays and Nebraska
Rainwater Basinsmust coincide with an extinction event in the eastern
half of the United States and the onset of a period of global cooling. This
combination of conditions is best met by the disappearance of the North
American megafauna, the end of the Clovis culture and the onset of the
Younger Dryas cooling event at 12,800 cal. BP. The report of a platinum
anomaly typical of extraterrestrial impacts at the Younger Dryas Boundary
by Petaev et al. (2013) supports this scenario. Further study of the
Carolina Bays may provide detailed insights about the late Pleistocene
and reveal information about near-Earth objects that could destroy
our civilization.
Acknowledgement
The author thanks Cintos.org for the use of LiDAR images licensed
under a Creative Commons Attribution-NonCommercial-ShareAlike
3.0 Unported License. The author would also like to thank two anonymous
referees and Prof. Andrew Plater whose comments helped to improve
this paper.
Appendix A. Supplementary data
Supplementary data associated with this article can be found in the
online version, at doi:10.1016/j.geomorph.2017.01.019. This data include
the Google maps of the most important areas described in this
article.
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