Welcome to another edition of the Carolina Bay of the Day.
In this episode, we will discuss a Carolina Bay in North Carolina that is 200 meters above
sea level and about 200 kilometers from the Atlantic Coast.
It is hidden in plain sight.
You cannot see it in aerial views or in satellite images.
Its elliptical geometry only becomes apparent when the terrain is viewed with LiDAR, which
is a laser ranging technology.
I received an email from Chris Cottrell that said: Hey Tony!
I have a special request for a "Bay of the Day" video about a Carolina Bay I stumbled
across with my students earlier today.
I think it has all the characteristics everyone needs to see, and is one of those outlier
Piedmont bays that has multiple 'street-view' angles and includes a road-cut rim.
Thanks and take care, Chris.
Chris is a science educator who has a YouTube channel called Dabbler's Den, where he discusses
the Carolina Bays and other topics.
In 2019, Chris and I participated in a research excavation of a Carolina Bay organized by
George Howard.
We obtained some soil samples of the layers and Chris and his students have helped to
process them for analysis.
This basin has all the typical attributes that characterize a Carolina Bay.
It is elliptical with raised rims, and it is oriented toward the Great Lakes.
The orientation is important because the Glacier Ice impact hypothesis proposes that the Carolina
Bays were created by oblique secondary impacts of glacier ice chunks ejected by one or more
extraterrestrial impacts on the Laurentide Ice sheet.
A satellite image of the same area shows some plowed fields and tree groves, but hardly
any trace of the Carolina Bay.
The terrain on which this bay is found is very hilly, but as we zoom in on its location
we can see that the bay is on a small flat area of the landscape.
Carolina Bays are sandy structures that are easily eroded on uneven terrain.
From the colorized topography of the LiDAR image, we can tell that the rim of the bay
is two to three meters higher than the center of the bay.
I selected eleven points along the perimeter of the bay and fitted them with an ellipse
by the least squares method.
All the points are on the ellipse and the fit demonstrates that this Carolina Bay has
a mathematically elliptical geometry.
The bay has a length of 727 meters and a width of 518 meters.
The azimuth of 130.5 degrees points just west of Lake Michigan, which after adjusting for
the rotation of the Earth should correlate to the point from which the ice chunk that
make this bay was launched.
The ballistic trajectory of the ice projectile would have had a flight time of 8.4 minutes
and reached a height of 313 kilometers above the surface of the Earth.
It was a suborbital space flight in the vacuum of space.
Ellipses are conic sections, and this implies that this Carolina Bay originated as an inclined
conical cavity or penetration funnel.
This is compatible with experimental results of ice projectiles striking a viscous target.
A viewer of one of my past videos admonished me by saying: Elliptical surface features
are consistent with conical cavities, but utterly fail to imply conical cavities; please
do not express this falsehood again.
It is not my intention to express falsehoods.
My statements are based on experiments showing that oblique impacts of ice projectiles on
a viscous surface produce inclined conical cavities with overturned flanges that become
shallow elliptical basins with raised rims after viscous relaxation.
When viewed from above, the inclined conical cavities look elliptical.
These experiments are small, but they demonstrate the laws of physics.
There is nothing false about it.
These experiments provide a credible, reproducible and scalable mechanism for the formation of
the Carolina Bays, and you can conduct similar experiments yourself.
The mechanisms shown in my experiments are described in the book Impact Cratering, A
Geologic Process by Professor Jay Melosh.
The section about Viscous Degradation of Craters says: Simple and complex craters are the immediate
result of impact crater excavation and collapse.
However, long after these rapid events have occurred, craters on most planetary bodies
continue to change and degrade toward the ultimate limit of gravitational stability:
a level plain.
The viscous relaxation process is illustrated in an image that shows a cavity decreasing
in depth from the bottom up.
Regarding the scalability of the physical model, Professor Melosh writes: the physics
of excavation is nearly the same for both microcraters and larger craters.
The main difference is that target strength dominates the excavation of microcraters whereas
gravity plays the dominant role for most geologically important craters.
Returning to our Carolina Bay, we see that the rim of the bay is crossed at four points
by two roads.
We can examine the surface features at the north, east, south and west crossings using
the Street View feature of Google Maps.
Samarcand road crosses the north rim of the bay.
The street view shows that the rim gently bulges about one meter above the road.
Route 211 crosses the east rim of the bay.
The LiDAR image shows a drainage ditch crossing under the road.
This is exactly what we see in the Street view.
Samarcand Road also crosses the south rim of the bay.
In this Street View, the camera is facing north, and we can see that the road, which
is on the rim of the bay, is slightly higher than the field to the right which is the center
of the bay.
Road 211 crosses the west rim of the bay.
The LiDAR image shows the road cutting through the rim.
The Street view shows a cross section of the raised rim on both sides of the road.
If you visit the area to look at these Carolina Bay rims, you may want to stop at the fruit
stand in the middle of the bay at the intersection of Samarcand Road and route 211.
This presentation emphasizes the importance of using LiDAR images for doing research on
the Carolina Bays.
There is a mathematically elliptical geological feature hidden in plain sight in this landscape.
But you cannot see it until you turn on the LiDAR visualization.
Thank you for joining me in the investigation of the Carolina Bays and the Younger Dryas
cataclysm.
There is a link to the LiDAR visualization tool in the description of the video.
I will continue to examine the mechanisms that made the Carolina Bays based on the principles
of experimental physics.
My book about the Carolina Bays is available at Amazon.
Please subscribe to my YouTube channel to be notified of future videos about the Carolina
Bays and other scientific topics.