Thread: The Carolina Bays are conic sections

1. Originally Posted by citpeks
I agree with you that finding the edges of the bays is difficult. My main point is that compared to the Alaskan lakes or the lakes in the Yamal peninsula, the Carolina Bays have remarkably elliptical shapes.
That's my point. It's difficult, therefore any claim of "perfect", "exact", "98%" cannot be made.

Originally Posted by citpeks
The variation in the ratios of the conic sections is another thing. This is a variation in the angles of the corresponding cones.
[...]
There should be some meaning in that.
Yes, it means that not only is the shape only roughly elliptical, but the ellipse shapes vary.
What is the meaning of any patterns in nature?

2. Originally Posted by grapes
But, even the limited amount of examples that you yourself have provided show that the Carolina Bays are only roughly elliptical.

The calculations you make using width-to-length ratios to calculate the angle of the cone depend upon them being perfect ellipses. That's clearly a false assumption.
The orbital calculations from Newtonian mechanics depend on the orbits being perfect ellipses. It is not quite so, is it? Nothing in nature is mathematically perfect. Close enough is sometimes good enough.

Here is an image of a lake in Alaska and a Carolina Bay.
Attachment 20642

In the following image I overlaid ellipses proportional to the length and the width at the midpoint. Even though you may find imperfections in the fit of the ellipse on the Carolina Bay, a mathematical test such as Least Squares Fitting could be used to quantify the degree of non-conformance in proportion to the area of the ellipse.

We can see that the Alaska lake has a poor fit with some boundaries inside the ellipse and other boundaries outside of the ellipse. This is clearly not elliptical.

Attachment 20641

It would clearly be wrong to try mathematical calculations on the Alaska lakes. However, the Carolina Bays are close enough to ellipses that we may learn something by using some mathematical calculations based on their shape.

3. Originally Posted by citpeks
The orbital calculations from Newtonian mechanics depend on the orbits being perfect ellipses. It is not quite so, is it?
Orbital calculations as perfect ellipses from Newtonian mechanics rely on 2 bodies. The reason they are not perfect is because there are more bodies influencing the orbits. When you consider the influences in the multiple bodies and take in relativity, they do become mathematically perfect.

These formations are from chaotic processes where many chaotic processes have some order.

Originally Posted by citpeks
Here is an image of a lake in Alaska and a Carolina Bay.

Originally Posted by citpeks
It would clearly be wrong to try mathematical calculations on the Alaska lakes. However, the Carolina Bays are close enough to ellipses that we may learn something by using some mathematical calculations based on their shape.
Only those that you are choosing to evaluate are "close enough" in your mind that you think a calculation would work.

The news media picks the most interesting pictures, other non mainstream sites also pick the most interesting ones and the ones that align with their agenda. We are not getting a full picture of the variety and variability. Then you go from that already non-representative set and apply your own selective reasoning.

This is like an analysis of paint spatters. We can determine the direction of the splatter by the shape and orientation of the spots, but there's nothing that can be found by trying to mathematically model the spots themselves.
In this case, the orientation has matched with theories of impacts (shown as not likely) or wind directions.

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I suppose Google-earthers have closely examined the circular swath of land between Carolina and Nebraska? There ought to be at least a few of these elliptical features along that path, unless one wants to argue that they're the ends of rays.

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Originally Posted by citpeks
My reason for posting on this forum is not to answer my own question, but to ask the help of geologists or geomorphologists...snipped lots of nitpicking...
My point remains, citpeks - why have you not asked geologists or geomorphologists for references to your demand for "the fluid mechanics calculations or numerical models that show how the elliptical or quasi-elliptical structures of the Carolina Bays are formed"?
These numerical models though might not exist. If they do not then you need to show that the mainstream scenarios are physically impossible before looking at other scenarios.
It is also fairly hopeful to think that geologists or geomorphologists specializing in the Bays hang out in this forum!

Originally Posted by citpeks
It is reasonable, but I am not satisfied with "roughly".
It is well known physics, citpeks: You have a basin or water. You release the water from the basin. Turbulent flow creates eddies. Eddies are roughly circular and cut out roughly circular depressions in the basin.

6. My theory on the formation of the Carolina Bays is due to the phenomena from karst topology. What underlies almost all of North Carolina than a huge bed of limestone? During the massive Ice Ages (Icehouse Earth), the massive mounds of ice actually suppressed the land underneath them through subsidence. As you push down on the poles, what happens to the equatorial region? It is forced out, or "squished out", however you wish to view it, through a process similar to isostasy. Since the land in this region was pushed slightly higher due to the polar ice caps, it started forming the "circular" and "elliptical" shape sink holes. However, the ice receded, allowing the land under the ice to begin rising again, as it is doing to this day. The Hudson Bay and Great Lakes areas are still rising due to the rebound of isostasy. Obversely, the region of eastern North Carolina is sinking due to subsidence. This has been proven by sophisticated GPS equipment. I have even participated in one such event here in NC. Over a three year period, the region we measured dropped 2.5mm. As the land subsided, ground water was forced up into the pre-sink holes. Before, the holes could actually sink, more silt and deposits filled-in these holes faster than they could be eroded away like a sink hole and actually become a sink hole.

Thus, you have your Carolina Bays. They are not caused by meteors. No evidence of a meteor has ever been found in any Carolina Bay.

One of my major areas of study was Geology, specifically Geomorphological Deformation. Of course, the above is an over simplified explanation. To fully explain, it would take the 383 pages from one of my text books.

rmfr
Last edited by arakish; 2015-Jul-12 at 07:36 PM. Reason: Added about NC on limestone

7. Originally Posted by arakish
My theory on the formation of the Carolina Bays is due to the phenomena from karst topology. What underlies almost all of North Carolina than a huge bed of limestone? During the massive Ice Ages (Icehouse Earth), the massive mounds of ice actually suppressed the land underneath them through subsidence. As you push down on the poles, what happens to the equatorial region? It is forced out, or "squished out", however you wish to view it, through a process similar to isostasy. Since the land in this region was pushed slightly higher due to the polar ice caps, it started forming the "circular" and "elliptical" shape sink holes. However, the ice receded, allowing the land under the ice to begin rising again, as it is doing to this day. The Hudson Bay and Great Lakes areas are still rising due to the rebound of isostasy. Obversely, the region of eastern North Carolina is sinking due to subsidence. This has been proven by sophisticated GPS equipment. I have even participated in one such event here in NC. Over a three year period, the region we measured dropped 2.5mm. As the land subsided, ground water was forced up into the pre-sink holes. Before, the holes could actually sink, more silt and deposits filled-in these holes faster than they could be eroded away like a sink hole and actually become a sink hole.

Thus, you have your Carolina Bays. They are not caused by meteors. No evidence of a meteor has ever been found in any Carolina Bay.

One of my major areas of study was Geology, specifically Geomorphological Deformation. Of course, the above is an over simplified explanation. To fully explain, it would take the 383 pages from one of my text books.

rmfr
I have no doubt that the Carolina Bays have been subject to a wide range of terrestrial processes. However, I have not encountered a good explanation yet of how the terrestrial processes could have generated such a large number of apparently elliptical features with a narrow range of width-to-length ratios. Such features are not seen in Alaska thermokarst or in the lakes of the Yamal peninsula in Russia. If there were just a few elliptical bays, I could agree that their shape could have arisen by chance through terrestrial processes. However, their radial alignment, which includes the Nebraska rainwater basins, is very peculiar and there is no satisfactory explanation that encompasses the bays in the East Coast and in Nebraska.

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Originally Posted by citpeks
However, I have not encountered a good explanation yet of how the terrestrial processes could have generated such a large number of apparently elliptical features with a narrow range of width-to-length ratios.
So you have never read the Carolina Bay Wikipedia article, citpeks ?
Geomorphology
Various geomorphological hypotheses have been proposed to account for the bays, including action of sea currents when the area was under the ocean or the upwelling of ground water at a later time. One major hypothesis within the earth sciences academic community is that a combination of processes created the shapes and orientations of these ancient landforms, including climate change, the formation of siliciclastic karst by solution of subsurface material during glacial sealevel lowstands and later modification of these depressions by periodic eolian and lacustrine processes.

Quaternary geologists and geomorphologists argue that the peculiar features of Carolina bays can be readily explained by known terrestrial processes and repeated modification by eolian and lacustrine processes of them over the past 70,000 to 100,000 years.[1] Also, Quaternary geologists and geomorphologists believe to have found a correspondence in time between when the active modification of the rims of Carolina bays most commonly occurred and when adjacent sand dunes were active during the Wisconsinan glaciation between 15,000 and 40,000 years (Late Wisconsinan) and 70,000 to 80,000 years BP (Early Wisconsinan).[2] In addition, Quaternary geologists and geomorphologists have repeatedly found that the orientations of the Carolina bays are consistent with the wind patterns which existed during the Wisconsinan glaciation as reconstructed from Pleistocene parabolic dunes, a time when the shape of the Carolina bays was being modified.[3]
Quaternary geologists and geomorphologists have good explanations of how terrestrial processes could have generated such a large number of apparently elliptical features with a narrow range of width-to-length ratios as in the Carolina Bays.
Alaska thermokarst are not Carolina Bays.
The lakes of the Yamal peninsula are not Carolina Bays.
Nebraska rainwater basins are AFAIK not counted as Carolina Bays.
Last edited by Reality Check; 2015-Jul-14 at 01:37 AM.

9. RealityCheck,

Thanks for the Wikipedia link. Even I have never read it. That Geomorphology excerpt is similar to some of the text in my text book for my class. My professor actually loved my hypothesis. Although I said theory above, I should have said hypothesis. My Geomorphology professor even said I could have used that hypothesis to write a dissertation. However, my main focus was into Geographical Information Science and Systems. I only took the Geomorphological Deformation class because the title sounded interesting. The class was also very interesting. I never knew it was going to cover such a broad range.

However, as pointed out by RealityCheck, there are many good explanations of how geomorphological processes could have formed the Carolina Bays the way they did. In the excerpt, it briefly, very briefly, touches on all of the geomorphological processes that could have formed the Carolina Bays.

Also think on this: In which direction is the semi-major axis oriented in all of the Carolina Bays? The same directional orientation of water drainage in eastern North Carolina? Yes, I know, some rivers actually loop around to the opposite direction at times, but the general overall flow of drainage is from the northwest to southeast. The same directional orientation of the semi-major axis of a Carolina Bay.

There are many ways the Carolina Bays could have all been formed. My hypothesis is only one. Perhaps, my hypothesis is just a small part of the overall formation process. Even I do not fully believe my hypothesis. It was just a thought that popped into my head as I thought about the subsidence created by the massive ice sheets and the resulting uplift it would cause elsewhere.

As mentioned in my previous post, since we know for a fact that the land that used to be under the ice sheets is rebounding upward, and the land south of there is subsiding, then logic could be used to show that the opposite is true. With the Carolina region being uplifted and the ocean levels lower, in my opinion only, this would seem that some karst erosion may have been occurring, possibly creating sink holes. However, before the sink holes could truly develop into true sink holes, the climate changed from an Icehouse Earth to a Greenhouse Earth. Thus, the ice caps melted, ocean levels rose which also rose the base level. Since the base level rose, that would mean ground water also rose, filling in those almost sink holes. Know what happens to a pond that does not drain? It fills in with silt, dirt, organic detritus, until the pond actually disappears and becomes land.

As said, my hypothesis may have had a small part in the formation of the Carolina Bays. However, I tend to believe it was the combination of eolian and fluvian processes that simply formed parabolic dunes that later got filled in. Thus, you will have elliptical formations.

Follow the link above to the wiki page. However, use the references links and external links for further research. It might not hurt much to visit the USGS site and some university geology sites.

Of course, to take on your viewpoint, the Carolina Bays could have been formed by a comet that shattered into a shotgun blast. Thus, no evidence of meteors ever found. However, this is unlikely since a comet that shatters would almost also detonate in the atmosphere, much like the Tunguska Event. Remember that Russian meteor just a little while back? Look at how much damage that little thing caused by atmospheric detonation. To this day, I still firmly disbelieve that the Carolina Bays were caused by an impact(s) event. I most firmly believe the geomorphological explanations.

rmfr

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I think that the range of ages of the Carolina Bays ("predating the end of the Pleistocene by ten of thousands to over a hundred thousand years") is the nail in the coffin of an impact event creating them. It was a reasonable hypothesis 60 years ago before carbon dating and optically stimulated luminescence were used to get these dates.

11. Originally Posted by Reality Check
I think that the range of ages of the Carolina Bays ("predating the end of the Pleistocene by ten of thousands to over a hundred thousand years") is the nail in the coffin of an impact event creating them. It was a reasonable hypothesis 60 years ago before carbon dating and optically stimulated luminescence were used to get these dates.
Exactly.

However, it bugs me to this day wondering if my hypothesis of partial karst topographical erosion had anything to do with their formation. I still wonder. But, I'll never know since my life has taken other directions away from that possibility. Most of my private studies (or self-studies) now take me into astrophysics, celestial mechanics, orbital mechanics, etc., I probably will never try to study Carolina Bays the way I use to when I was a kid back when Tyrannosaurs ruled.

Thus, my hypothesis.

I have since found that a land developer has since "plowed and filled" that Carolina Bay. Shame. It would have been wonderful to continue studying it to see if actually became a sinkhole, later forming into another Carolina Bay.

rmfr

12. O! Yes, citpeks. ANY ellipsoid is a conic section. That is a geometric proof.

rmfr

13. Originally Posted by arakish
O! Yes, citpeks. ANY ellipsoid is a conic section. That is a geometric proof.

rmfr
It is not enough to just have an ellipse. There are also the constraints of axial orientation and width-to-length ratios. These are essential features of the Carolina Bays.

Image

Carolina Bays also are located only on unconsolidated soil and they have raised sandy rims.
Last edited by PetersCreek; 2015-Jul-17 at 07:30 PM. Reason: Image too large

14. I'm looking at your image, and it's quite clear that things aren't as exact as all that. There are other features in that image that appear to be the same thing (I'm not familiar with this feature) and aren't all that elliptical, and it's obvious to me that your superimposed ellipses do not completely cover the ones you have chosen.

15. citpeks,

At 283,436 bytes, the larger image you change to busts our image guidelines by a very wide margin so I have converted it to a link. Please see our rules for more details.

16. Originally Posted by citpeks
It is not enough to just have an ellipse. There are also the constraints of axial orientation and width-to-length ratios. These are essential features of the Carolina Bays.

Image

Carolina Bays also are located only on unconsolidated soil and they have raised sandy rims.
That's a fascinating image! Where is it, lat/lon?

The whole thing is covered with 'em! Different orientations, and overlapping ones. The smaller ones seem to be more circular.

17. Originally Posted by Gillianren
I'm looking at your image, and it's quite clear that things aren't as exact as all that. There are other features in that image that appear to be the same thing (I'm not familiar with this feature) and aren't all that elliptical, and it's obvious to me that your superimposed ellipses do not completely cover the ones you have chosen.
I have been fitting the ellipses at the margin between the center of the bays and the raised rims. There may be some deviation between the geological structures and the mathematical curves. The amount of deviation could be quantified by measuring the number of square meters of the actual structure which are inside or outside the ellipse and then dividing that number by the overall area of the ellipse. In general, the fit is very good.

Geological structures are modified by erosion from wind and water, and by distortions caused by ground movements. Some deviation from the theoretical does not invalidate the observation that the Carolina Bays are true ellipses as long as the deviation is not too great. By analogy, we consider the planets to be spherical, but none are truly spherical. Even the shape of the gas giants that have no mountains is distorted by their rotation. Theoretically speaking, planets are spherical and the Carolina Bays are elliptical.

18. Originally Posted by grapes
That's a fascinating image! Where is it, lat/lon?

The whole thing is covered with 'em! Different orientations, and overlapping ones. The smaller ones seem to be more circular.

The image is of the Carolina Bays 37 km southwest of Fayetteville, NC viewed with LiDAR
(Lat. 34.850, Lon. -79.205)

LiDAR has made a big difference of how the Earth can be viewed. Many geological features that are invisible from aerial views become evident with LiDAR.

There is an online LiDAR viewer for the Carolina Bays here:
http://cintos.org/code/100kViewer/index.html

19. Originally Posted by citpeks
I have been fitting the ellipses at the margin between the center of the bays and the raised rims. There may be some deviation between the geological structures and the mathematical curves. The amount of deviation could be quantified by measuring the number of square meters of the actual structure which are inside or outside the ellipse and then dividing that number by the overall area of the ellipse. In general, the fit is very good.
It didn't look it to me. It looked cherry-picked.

Geological structures are modified by erosion from wind and water, and by distortions caused by ground movements. Some deviation from the theoretical does not invalidate the observation that the Carolina Bays are true ellipses as long as the deviation is not too great. By analogy, we consider the planets to be spherical, but none are truly spherical. Even the shape of the gas giants that have no mountains is distorted by their rotation. Theoretically speaking, planets are spherical and the Carolina Bays are elliptical.
Actually, we consider planets to be oblate spheroids, and "round" is a shorthand for people who don't know the term "oblate spheroid."

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Originally Posted by citpeks
It is not enough to just have an ellipse. There are also the constraints of axial orientation and width-to-length ratios. These are essential features of the Carolina Bays.
citpeks, We know what the features of the Carolina Bays are:
Carolina bays are elliptical depressions concentrated along the Atlantic seaboard within coastal Delaware, Maryland, New Jersey, North Carolina, South Carolina, Virginia, Georgia, and northcentral Florida (Prouty 1952, Kaczorowski 1977). ...
Carolina bays vary in size from one to several thousand acres. About 500,000 of them are present in the classic area of the Atlantic Coastal Plain, often in groups, with each bay invariably aligned in a northwest-southeast direction.
We do not need repeated images (no matter how interesting ) to recognize the basic fact that Carolina Bays are elliptical and oriented. That they are not perfect ellipses is also a real world fact - no one expects them to be perfect!

Is that the end of this thread, citpeks - you are repeating basic facts which everyone who reads about the Carolina Bays knows?
Or are you claiming that you being able to draw an eclipse on some bays in some images is significant in some way?

For example you have ellipses on a few of the bays in that LIDAR image. But anyone can see that the ones you ignore include
* bays with multiple rims.
* bays that are not quite oriented with the images you picked.
* overlapping bays that may or may not be elliptical.
* non-elliptical bays , e.g. with one end pointed and another end rounded.
ETA: You have also hidden the features of the bays that you picked with the overlay of a solid ellipse.

A true ellipse would be one that is perfectly elliptical. You draw a ellipse around the feature and that ellipse matches the rim at every point even if the line is infinitesimally thin. You need a rim that is infinitesimally thin!
A "true" ellipse could be a feature that is elliptical within the errors of measurement. For example draw a series of ellipses around the feature so that every ellipse lies within the rim. From that you get a range of elliptical parameters.
A bay with multiple rims could never be a "true" ellipse. A bay with a non-elliptical shape could never be a "true" ellipse.
Last edited by Reality Check; 2015-Jul-19 at 11:59 PM.

21. Originally Posted by Reality Check
citpeks, We know what the features of the Carolina Bays are:

We do not need repeated images (no matter how interesting ) to recognize the basic fact that Carolina Bays are elliptical and oriented. That they are not perfect ellipses is also a real world fact - no one expects them to be perfect!

Is that the end of this thread, citpeks - you are repeating basic facts which everyone who reads about the Carolina Bays knows?
Or are you claiming that you being able to draw an eclipse on some bays in some images is significant in some way?

For example you have ellipses on a few of the bays in that LIDAR image. But anyone can see that the ones you ignore include
* bays with multiple rims.
* bays that are not quite oriented with the images you picked.
* overlapping bays that may or may not be elliptical.
* non-elliptical bays , e.g. with one end pointed and another end rounded.
ETA: You have also hidden the features of the bays that you picked with the overlay of a solid ellipse.

A true ellipse would be one that is perfectly elliptical. You draw a ellipse around the feature and that ellipse matches the rim at every point even if the line is infinitesimally thin. You need a rim that is infinitesimally thin!
A "true" ellipse could be a feature that is elliptical within the errors of measurement. For example draw a series of ellipses around the feature so that every ellipse lies within the rim. From that you get a range of elliptical parameters.
A bay with multiple rims could never be a "true" ellipse. A bay with a non-elliptical shape could never be a "true" ellipse.
Sometimes an image is worth more than a thousand words. The large image elicited a surprised reaction from grapes, although he had participated in the ATM thread to stop ignoring the Carolina Bays.

I like your suggestion of drawing a series of ellipses to get a range of elliptical parameters. Maybe this is something that can be done when the mapping of the Carolina Bays becomes a community project like the mapping of the craters of the Moon, Mercury, etc.

I still have not found a source that satisfactorily explains the formation of the bays by terrestrial processes. Experts seem to have diverging ideas about how the shapes of the Carolina Bays originated. Prof. Melosh from Purdue University says that the Carolina Bays are aligned with the prevailing wind, whereas Prof. Brooks from the University of South Carolina in Columbia says that the elongation of the Carolina Bays is perpendicular to the wind direction.

Melosh, H.J., 2011, Planetary Surface Processes, Cambridge University Press, p. 462.
"Thawed permafrost expels water and contracts, sagging downward into small ponds that collect more water and enhance melting. Such thaw lakes are common, creating landscapes packed with kilometer-diameter circular to elliptical ponds that are often aligned with the prevailing wind. Such lakes constitute the infamous Carolina Bays, which impact-crater enthusiasts persistently claim to be of impact origin in spite of the complete lack of evidence for impacts."

Brooks, M. J.; B. E. Taylor; and A. H. Ivester, 2010, Carolina bays: time capsules of culture and climate change. Southeastern Archaeology. vol. 29, pp. 146–163.
"The distinctive shape and NW–SE orientation of bays developed through stronger-than-present southwesterly winds blowing over water ponded in shallow depressions (Brooks et al. 2001b; Carver and Brook 1989; Kaczorowski 1977; Thom 1970). The depressions were expanded and oriented by wave erosion, resulting in bay elongation perpendicular to wind direction and the formation of peripheral, downwind sand rims and shorelines on the eastern and southeastern margins, which were the preferred locations for settlement (Brooks et al. 1996a, 1996b)."

22. Originally Posted by citpeks
Sometimes an image is worth more than a thousand words. The large image elicited a surprised reaction from grapes, although he had participated in the ATM thread to stop ignoring the Carolina Bays.
But that's still only a very small percentage of the population and not necessarily a representative sampling.
And the surprised reaction is about the picture, not about the orientation. Even Grapes said "Different orientations, and overlapping ones. The smaller ones seem to be more circular."

Originally Posted by citpeks
I like your suggestion of drawing a series of ellipses to get a range of elliptical parameters. Maybe this is something that can be done when the mapping of the Carolina Bays becomes a community project like the mapping of the craters of the Moon, Mercury, etc.
How about a first step with you re-drawing your ellipses with a narrow border and not filling in the ellipse to hide the features underneath?

Originally Posted by citpeks
Prof. Melosh from Purdue University says that the Carolina Bays are aligned with the prevailing wind, whereas Prof. Brooks from the University of South Carolina in Columbia says that the elongation of the Carolina Bays is perpendicular to the wind direction.
Alignment does not necessarily specify direction. It very well could be aligned perpendicularly to the wind.
Besides, I find it hard to believe that two experts can be 90 degrees off from the apparent major axis, or 90 degrees off of wind direction.

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Craters of the Rio Cuarto
also here.

Carolina bays look different.

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Originally Posted by citpeks
Sometimes an image is worth more than a thousand words...
In science a proper analysis of an image is worth more than a million words, citpeks. An improper analysis of an image is not worth the paper it is not written on.

You state you have not found a source that "satisfactorily" explains the formation of the bays by terrestrial processes. And then you list two sources !
The terrestrial process of thaw lakes: Melosh, H.J., 2011, Planetary Surface Processes, Cambridge University Press, p. 462.
The terrestrial process of wind action on depressions: Brooks, M. J.; B. E. Taylor; and A. H. Ivester, 2010, Carolina bays: time capsules of culture and climate change. Southeastern Archaeology. vol. 29, pp. 146–163.
This unfortunately makes it sound like no science will satisfy you.

ETA: The two authors do seem to contradict each other as how wind direction affects the bays but you have only quoted a couple of sentences. Brooks is talking about past winds. Maybe Melosh's prevailing winds are todays winds.
Last edited by Reality Check; 2015-Jul-21 at 12:21 AM.

25. Originally Posted by NEOWatcher
...
How about a first step with you re-drawing your ellipses with a narrow border and not filling in the ellipse to hide the features underneath?
I did that in a previous thread.

az0001-ellipse-overlay.jpg

Generally, the bay interiors are featureless planes, but many have drainage channels.

26. Originally Posted by citpeks
I did that in a previous thread.
Well, that's one.

Originally Posted by citpeks
Generally, the bay interiors are featureless planes, but many have drainage channels.
But the interior is not the point. The point is that you obstructed the features near the edge. For instance, in this picture, the lower left is well outside the rim.

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Originally Posted by citpeks
Generally, the bay interiors are featureless planes, but many have drainage channels.
The problem is that the bays may have multiple rims and non-elliptical shapes (as in your image). That suggests the possibility of cherry picking bays or a specific rim in a bay to get an elliptical shape. Thus the need to never hide any part of a bay that you are drawing an ellipse on, citpeks.

28. Originally Posted by citpeks
I have been fitting the ellipses at the margin between the center of the bays and the raised rims. There may be some deviation between the geological structures and the mathematical curves. The amount of deviation could be quantified by measuring the number of square meters of the actual structure which are inside or outside the ellipse and then dividing that number by the overall area of the ellipse. In general, the fit is very good.

Geological structures are modified by erosion from wind and water, and by distortions caused by ground movements. Some deviation from the theoretical does not invalidate the observation that the Carolina Bays are true ellipses as long as the deviation is not too great. By analogy, we consider the planets to be spherical, but none are truly spherical. Even the shape of the gas giants that have no mountains is distorted by their rotation. Theoretically speaking, planets are spherical and the Carolina Bays are elliptical.
What you are doing is trying to fit the ellipsoids to the actual geographical "SUPER" ellipses using Photoshop. Believe me, I tried with PS4. In my second year of Geology courses at NCSU.

It DOES NOT work. You need true GIS/GPS points to find they are NOT true ellipses. They are "SUPER" ellipses. A super concentration of ellipses overlayed upon each other indicative of a "huge" meteor impact. As the splashback happens, many pieces of the Earth's crust would have been propelled upward to fall in a short distance from the impact event.

Do you think the chunks of crustal material falling back may have caused "elliptical" craters as they fell back to Earth?

It can happen.

Think more. I find your arguments fascinating.

rmfr

P.S. - Yes. I am changing my argument from karst topology to the meteor impact. There was a big one off the "current" DelMarVa peninsula. Ever notice the ring like structure of the "Outer Banks"?

29. Originally Posted by Squink
Craters of the Rio Cuarto
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Carolina bays look different.
Yes. They do. As they should.

Two different parts of the same world with two different climatic regions.

If they did not look different on the same globe with wildly different climatic zones, then I would suspect.

rmfr

30. It would appear we are straying out of the bounds set in post #2:

Clarified: this thread is intended to discuss the geomorphology and geometry of the Carolina Bays and Nebraska rainwater basins. Related discussion about their origins must be consistent with currently accepted mainstream model(s).

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