Meteoric Impacts on ice.

[JohnB]

This question, while it had a genesis in reading about climate change isn't about climate per se.

 

When we read about meteoric impacts we tend to think of them as occurring on land or in the water. I've read no end of articles about the ejecta and ash from a land impact and we've had big budget movies about water impacts. Giant waves, the whole bit, we all know what will happen if a big enough rock hits the water.

 

So what happens when it hits ice?

 

20,000 years ago much of North America and EurAsia was covered with a couple of miles of ice. A meteorite large enough to bury itself a mile underground hitting so much ice wouldn't even make it to the dirt. It would make a big hole in the ice and most of the ejecta would be ice fragments.

 

Would we be able to even detect that such an event had occurred? The only material available to form an ash layer would have to come from the impactor itself. Presumably most of the material would settle relatively near to the crater, but that is also on top of the ice. When the Ice Age ended and the sheets melt, all that material will get washed to the sea. (At least I would think so)

 

So, what happens when a "city killer" hits an ice sheet 2 miles thick?

[Moontanman]

This question, while it had a genesis in reading about climate change isn't about climate per se.

 

When we read about meteoric impacts we tend to think of them as occurring on land or in the water. I've read no end of articles about the ejecta and ash from a land impact and we've had big budget movies about water impacts. Giant waves, the whole bit, we all know what will happen if a big enough rock hits the water.

 

So what happens when it hits ice?

 

20,000 years ago much of North America and EurAsia was covered with a couple of miles of ice. A meteorite large enough to bury itself a mile underground hitting so much ice wouldn't even make it to the dirt. It would make a big hole in the ice and most of the ejecta would be ice fragments.

 

Would we be able to even detect that such an event had occurred? The only material available to form an ash layer would have to come from the impactor itself. Presumably most of the material would settle relatively near to the crater, but that is also on top of the ice. When the Ice Age ended and the sheets melt, all that material will get washed to the sea. (At least I would think so)

 

So, what happens when a "city killer" hits an ice sheet 2 miles thick?

 

Total speculation here but i see no reason it would be any different than hitting 2 miles of water as far as ejecta is concerned.

[Airbrush]

Yes it seems like 2 miles of ice is nearly the same as 2 miles deep of water for an asteroid. It would easily punch through the ice and instantly heat the area enough to melt and vaporize the nearby ice very quickly.

 

Your ice impact theory is I think one explanation for the disappearance of the Clovis people and mega-fauna from North America, over 10,000 years ago. If there was over a mile deep of ice, it could absorb all the impact or Tunguska-like air blast, then evidence melts away.

Edited November 23, 2011 by Airbrush

[John L]

 

So, what happens when a "city killer" hits an ice sheet 2 miles thick?

 

Could you be more specific here? Mass and speed will make a difference. For example asteroids, which are usually remnants of former comets, tend to be smaller, and much slower. If a comet enters our atmosphere and slams into a large ice sheet, the kinetic energy is going to be far greater. But comets tend to calve upon entry and there are usually many potential impactors.

 

Also, have you had a chance to study the subject of Carolina Bays? George Howard has a wealth of information on this, right here. Whether this is directly linked to the 'so called' Clovis Comet, is still unknown, but clearly the evidence of multiple strikes is self-evident.

 

Its a shame that the most vocal proponent on the Clovis Comet appears to have taken some very unscientific shortcuts, to the point where it has tainted the concept. Personally I believe this event to have occurred, causing the sudden Younger Dryas cooling. But then again, I'm one of those Impactor fanatics.

 

Anyway, just what do you mean by 'city killer': a fifty metre object, or perhaps something much bigger? Because its just possible the Impactor actually exploded in the atmosphere and resulted in multiple strikes, which may have had more damaging consequences. Anyway, check out the images of the Carolina Bays to get a better idea of the shooting gallery we live in.

 

Carolina Bays Images

 

[Moontanman]

Could you be more specific here? Mass and speed will make a difference. For example asteroids, which are usually remnants of former comets, tend to be smaller, and much slower. If a comet enters our atmosphere and slams into a large ice sheet, the kinetic energy is going to be far greater. But comets tend to calve upon entry and there are usually many potential impactors.

 

Also, have you had a chance to study the subject of Carolina Bays? George Howard has a wealth of information on this, right here. Whether this is directly linked to the 'so called' Clovis Comet, is still unknown, but clearly the evidence of multiple strikes is self-evident.

 

Its a shame that the most vocal proponent on the Clovis Comet appears to have taken some very unscientific shortcuts, to the point where it has tainted the concept. Personally I believe this event to have occurred, causing the sudden Younger Dryas cooling. But then again, I'm one of those Impactor fanatics.

 

Anyway, just what do you mean by 'city killer': a fifty metre object, or perhaps something much bigger? Because its just possible the Impactor actually exploded in the atmosphere and resulted in multiple strikes, which may have had more damaging consequences. Anyway, check out the images of the Carolina Bays to get a better idea of the shooting gallery we live in.

 

Carolina Bays Images

 

 

 

John, I live among the Carolina Bays, I also know scientists who study them (not personally but I have met some) very few if any real geologists think the Carolina Bays were formed by meteorite impacts, most think the bays were formed underwater by currents in a shallow sea, there is no evidence of impact forming those bays....

[John L]

You are saying that these slightly less than perfectly round circles, are the result of underwater currents?

 

And just how did these underwater currents manage to create them? And a huge number of these occur above the ancient 'fall line'. So how did they get under water, especially so recently?

 

But this is slightly off track other than the fact that the possible cause may have been the result of the Saginaw Impact, which would have been above the ice sheet boundary of the last recent round of the Pleistocene. Which may have something to do with the other John's question about leaving evidence of an impactor within the geologic record.

[Moontanman]

You are saying that these slightly less than perfectly round circles, are the result of underwater currents?

 

And just how did these underwater currents manage to create them? And a huge number of these occur above the ancient 'fall line'. So how did they get under water, especially so recently?

 

But this is slightly off track other than the fact that the possible cause may have been the result of the Saginaw Impact, which would have been above the ice sheet boundary of the last recent round of the Pleistocene. Which may have something to do with the other John's question about leaving evidence of an impactor within the geologic record.

 

 

John, I honestly don't know the details, I've had it explained to me many many years ago by a geologist and a oceanographer, actually over the years more than 3 or 4 of them as a matter of fact. The mail deal is that no evidence of meteor impact at the sites and the fact that many of them point in odd directions and that an actual impact is highly unlikely to leave a oval crater much less many of them, some in odd directions, all in the same place. The deal with the currents didn't stick all that well in my memory but I have dived in the ones that are full of water and they all (the ones I've dived in anyway) have springs issuing from the bottom and there is no fractured rock strata associated with them...

[John L]

Perhaps the Carolina Bays issue deserves another separate thread. There is a great deal of recent data I need to research as well. Its been a couple of years since I followed the trails.

 

But I mentioned that because of the Saginaw Bay crater, above where the ice sheet reached its southerly limits, could possibly be the origin of the Carolina bays. And too, I am not privy to its age either. I would like to know this as well, because if it did strike the ice sheet, it would indicate something of the size and speed of the Impactor.

Edited November 25, 2011 by John L

[Moontanman]

Perhaps the Carolina Bays issue deserves another separate thread. There is a great deal of recent data I need to research as well. Its been a couple of years since I followed the trails.

 

But I mentioned that because of the Saginaw Bay crater, above where the ice sheet reached its southerly limits, could possibly be the origin of the Carolina bays. And too, I am not privy to its age either. I would like to know this as well, because if it did strike the ice sheet, it would indicate something of the size and speed of the Impactor.

 

 

Another thread would be a good idea and i'll see if I can come up with anything to support my assertion other than an old memory...

 

Bold is mine, this is what I was told....

 

http://en.wikipedia.org/wiki/Carolina_Bay

 

Theories of Origin

More than a dozen bays are shown in this photo in southeastern North Carolina. Several are cleared and drained for farming.

Theories of the origin of the Carolina bays fall into two major categories: that these features were created by forces within the Earth, or that they were gouged by an astronomical event or set of events.

[edit]Geomorphology

Various geomorphological theories 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 theory 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 siliclastic karst by solution of subsurface material during glacial sealevel lowstands and later modification of these depressions by periodic eolian and lacustrine processes.

Various proposals that they were either directly or indirectly created by a meteorite shower or exploding comet are disputed by many scientists for an apparent lack of extraterrestrial material, absence of shocked quartz and "bedrock" deformation associated with larger bays, and extremely low ratio of depth to diameter of the larger bays. More information on these theories can be found at: Carolina Bays.

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. [2]. 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 Wisconsin glaciation between 15,000 and 40,000 years and 70,000 to 80,000 years BP [3]. 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 Wisconsin glaciation as reconstructed from Pleistocene parabolic dunes, a time when the shape of the Carolina bays was being modified [4].

[edit]Impact event

The cometary impact theory of the origin of the bays was popular among earth scientists of the 1930s and 40s. It said that they were the result of a low density comet exploding above or impacting with the Laurentide ice sheet about 12,900 years ago.[1]

New hypotheses arose again in the 1980s and 1990s, spurred on by various attention to impacts such as the Tunguska event, Cretaceous–Tertiary extinction event and a theorized link to the unsolved scientific mystery of the Younger Dryas event. Impact geologists determined the depressions are too shallow to be impact features. Reports of magnetic anomalies turned out not to show consistency across the sites. There were no meteorite fragments or impact crater geologic structures. None of the necessary evidence for an impact was found. The conclusion was to reject the impact theory at the Carolina bays.[2]

Edited November 25, 2011 by Moontanman

[michel123456]

 

Carolina Bays Images

 

 

What is this white dot in the center of some bays?

[John L]

What is this white dot in the center of some bays?

 

My guess is that the white marks are the result of someone studying the photo. Note the same marks on irrigation squares not associated with the circles.

 

Here is what unmarked photos look like.

 

 

 

 

 

As for the age of the bays, clearly there are multiple strikes associated with them. many of the bays are overlapping, and some are inside others, so they were almost certainly the result of more than one Impactor strike. If you study the picture above closely, you can see older circles, and newer circles that are overlapping older ones.

 

By using the oval shape of the bays, it is easy to orient it to the direction from whence the objects originated. And the majority of the latest ones appear to originate from a common source, the so called Saginaw site.

 

Also, the latest ones are much more recent than perhaps others, indicating a strike at the trailing end of the more recent Wisconson(Wurm) stage of the Pleistocene.

 

But in answer to JohnB's question about an impactor on the ice sheet, it's size, impression on the geology, and spread of debris, the answer would be the size and kinetic energy of the inpactor.

 

Let's say the Saginaw site, or any other site on or above the area, are within the time frame of the Pleistocens(2.5 million years bp), then the odds are at least 90% that they occurred over the ice sheets that extended southward. Only during an interglacial, such as today's Holocene, would there be no ice present at the impactor site. This means the impactor's kinetic energy was sufficient to instantly melt the ice sheet, and continue driving into the landscape beneath it. That's a lot of kinetic energy being transfered from the object.

 

And that would tend to throw out a lot of debris, mostly in the direction the object was traveling. That is why the bays are being used to back track to the source, by studying the shape of the craters.

 

Now, if there are so many overlapping craters, under such a huge number of recent ones, then this is clear evidence the planet is being hit by Impactors on a regular basis, geologically.

 

It has been several decades since Shoemaker turned things upside down with the revelation of impactors and their impact(pardon the pun) on the globe, and clearly its significance has not become fully appreciated within the scientific community even yet.

 

I'm not a geologist(I'm a physical anthropologist), and I can see how impactors are clearly so important to how this planet has been affected. As I have stated before in another thread, we are living in one celestial shooting gallery, and assume we are not going to occasionally get a black eye, is sheer hubris on our part.

Edited November 25, 2011 by John L

[Moontanman]

As for the age of the bays, clearly there are multiple strikes associated with them. many of the bays are overlapping, and some are inside others, so they were almost certainly the result of more than one Impactor strike. If you study the picture above closely, you can see older circles, and newer circles that are overlapping older ones.

 

By using the oval shape of the bays, it is easy to orient it to the direction from whence the objects originated. And the majority of the latest ones appear to originate from a common source, the so called Saginaw site.

 

Also, the latest ones are much more recent than perhaps others, indicating a strike at the trailing end of the more recent Wisconson(Wurm) stage of the Pleistocene.

 

But in answer to JohnB's question about an impactor on the ice sheet, it's size, impression on the geology, and spread of debris, the answer would be the size and kinetic energy of the inpactor.

 

Let's say the Saginaw site, or any other site on or above the area, are within the time frame of the Pleistocens(2.5 million years bp), then the odds are at least 90% that they occurred over the ice sheets that extended southward. Only during an interglacial, such as today's Holocene, would there be no ice present at the impactor site. This means the impactor's kinetic energy was sufficient to instantly melt the ice sheet, and continue driving into the landscape beneath it. That's a lot of kinetic energy being transfered from the object.

 

And that would tend to throw out a lot of debris, mostly in the direction the object was traveling. That is why the bays are being used to back track to the source, by studying the shape of the craters.

 

Now, if there are so many overlapping craters, under such a huge number of recent ones, then this is clear evidence the planet is being hit by Impactors on a regular basis, geologically.

 

It has been several decades since Shoemaker turned things upside down with the revelation of impactors and their impact(pardon the pun) on the globe, and clearly its significance has not become fully appreciated within the scientific community even yet.

 

I'm not a geologist(I'm a physical anthropologist), and I can see how impactors are clearly so important to how this planet has been affected. As I have stated before in another thread, we are living in one celestial shooting gallery, and assume we are not going to occasionally get a black eye, is sheer hubris on our part.

 

So even though I easily found information that debunks the impact theory completely you are gonna go with an impact anyway?

 

There is no evidence for impact event

 

The bays are of differing ages and show sign of being gradually formed over time

 

They are not as accurately placed as many would have you believe

 

All I had to do was go to wiki and see the very things that people here who actually study these thing have demonstrated to be true.... have told me

 

http://en.wikipedia.org/wiki/Carolina_Bay

[John L]

I'm sorry, but theses are clearly impact sites. The odds of all of them being shaped the way they are, and tending to be patterned on like axis, is obviously not a random creation caused by 'terrestrial processes'. These are the result of 'celestial processes'.

 

And what do these 'so called' terrestrial processes represent anyway: oceanic movement; underground release of hydrate gas pockets; or other unknown acts?

 

These are all the result of one or more larger impacts from celestial events. If they aren't from an immediate, and larger, impact, they are obviously from an air burst, which threw out many smaller objects, impacting onto the planet's surface.

 

I don't understand why so many people find it so difficult to conceive of the notion that we are being bombarded from space, on certainly an irregular basis.

 

And there is even the possible conjecture that comets tend to be disturbed on a regular basis, either through movement up and down the galactic plane, or perhaps the presence of something like a brown dwarf that has an elongated orbit of our sun that may be every thirty to thirty-two million years. And these comets tend to move into the gravity well, where some of them wind up colliding with our planet, causing mass extinctions.

 

I'm sorry, but this to me is as elemental as the nose on one's face. And until someone can prove that these 'bays' are caused by something terrestrial, beyond reasonable doubt, I'm going to go with the Celestial Impact cause.

 

But let me go over one of the things mentioned in Wikipedia you want to follow: And keep in mind that just because Wikipedia said it doesn't make it the gospel. Their issue with the global warming debate proves this already.

 

But take this part:

 

Impact geologists determined the depressions are too shallow to be impact features. Reports of magnetic anomalies turned out not to show consistency across the sites. There were no meteorite fragments or impact crater geologic structures. None of the necessary evidence for an impact was found. The conclusion was to reject the impact theory at the Carolina bays.[2]

 

As for the part about there being no meteorite fragments, perhaps these have not been found yet. Perhaps a good deal of this could have been from some of all that ice sheets being blown away due to the initial impact. Once ice melts, it leaves only water behind.

 

And perhaps an air burst could have accomplished this, leaving little remains in concentration. The Tunguska event in Siberia is less than one hundred years old, and the remains there are scanty because it was an air detonation.

 

And the Wikipedia insert also claims that the bays are too shallow for them to have been impact craters. That assumes there is no such thing as weathering by a planet that constantly weathers everything else on the surface. And within an area where there is abundant rainfall, weathering would be extensive to say the least.

 

I just don't understand the lack of reason when it comes to impacts and impactors.

Edited November 25, 2011 by John L

[michel123456]

What is the nature of the ground? It looks sedimental to me. Wouldn't an impact on sedimental ground have been erased by erosion a long time ago?

[Moontanman]

I'm sorry, but theses are clearly impact sites. The odds of all of them being shaped the way they are, and tending to be patterned on like axis, is obviously not a random creation caused by 'terrestrial processes'. These are the result of 'celestial processes'.

 

And what do these 'so called' terrestrial processes represent anyway: oceanic movement; underground release of hydrate gas pockets; or other unknown acts?

 

These are all the result of one or more larger impacts from celestial events. If they aren't from an immediate, and larger, impact, they are obviously from an air burst, which threw out many smaller objects, impacting onto the planet's surface.

 

I don't understand why so many people find it so difficult to conceive of the notion that we are being bombarded from space, on certainly an irregular basis.

 

And there is even the possible conjecture that comets tend to be disturbed on a regular basis, either through movement up and down the galactic plane, or perhaps the presence of something like a brown dwarf that has an elongated orbit of our sun that may be every thirty to thirty-two million years. And these comets tend to move into the gravity well, where some of them wind up colliding with our planet, causing mass extinctions.

 

I'm sorry, but this to me is as elemental as the nose on one's face. And until someone can prove that these 'bays' are caused by something terrestrial, beyond reasonable doubt, I'm going to go with the Celestial Impact cause.

 

 

How can the Idea of impact forming them be obvious as the nose on your face when none of the data supports the idea of impacts, there is no shocked quartz, many of the bays are of different ages, and a natural method formation has been worked out and it doesn't involve impacts, do you only read that which agrees with you? On top of that oval craters are quite rare, even coming in at an extreme angle usually makes a round crater, we are not talking about bullets here, these impacts would been hugely energetic and when the ice chucks hit they would be balls of hot plasma not chunks of cold ice....

[michel123456]

Browsing for "elliptical impact" the first answer was this

This image shows what appears to be a highly elliptical crater, which would be unusual.

Closer examination reveals that it is probably two overlapping craters that formed concurrently, plus several smaller craters aligned with the long axis of the elliptical depression.

This type of crater chain can form from a highly oblique impact, in which the bolide trajectory is almost parallel to the surface.

emphasis mine.

 

and this article

ScienceDaily (May 5, 2009) — Nearly all meteorite impact craters on Earth are circular. Elongated crater structures are expected only at impacts at angles lower than 12 degrees from the horizontal. Kenkmann and Poelchau document the first elliptical crater on Earth that provides insights into the mechanisms of crater formation at low angles.

 

It seems elliptical crater is a rare phenomenon.

Edited November 25, 2011 by michel123456

[John L]

 

[michel123456]

This is what you mean I guess: Correlating the Orientation of Carolina bays to a Cosmic Impact

[John L]

This is what you mean I guess: Correlating the Orientation of Carolina bays to a Cosmic Impact

 

Correct! This is a whole lot more logical than some hypothetical 'oceanic currents', or 'gas pockets' theory, which are even harder to prove.

 

This reminds me of the Permian Extinction event, and how the anti-celestial folks tend to write it off. To them it was caused by the massive Siberian Fault volcanic eruptions.

 

Well, so what? Anyone, who looks at the Permian event has a pretty good idea where it occurred(Antarctica). And if one looks to the opposite side of the globe, one will find the Siberian area where all those volcanoes were set off. Now just what could have possibly caused it, if the impact crater was at the opposite side of the planet?

 

Well, first of all, the planet has a thin crust, and shock waves tend to ripple outward in all directions. And where will all those ripples finally end up, all at once? If you say Siberia, YOU WIN!! And with all that shock striking all at once, does anyone think it just might cause the plates to open up and go haywire? The internal pressure would be enormous too.

 

Nine of ten, or more, cataclysmic events are the result of celestial means, in one form or another.

Edited November 25, 2011 by John L

[Moontanman]

I never said that oval craters were impossible or didn't happen but they are rare but the main thing you have to answer about the Carolina Bays is why there is no evidence of any impact at the sites, their ages are around 100,000 years old not a few thousand and there is no shocked quartz or any other mineral, no evidence of any extraterrestrial material associated with the bays, core samples do not indicate they were once deeper and filed with sediment. You show all the triangulation in the world but the fact remains there is no evidence they were caused by impacts, none, shape alone does not a crater make and incredulity about aeolian and water explainations do not make them invalid.

 

I had to go no further than wiki to find the explanation that was given me by local experts who have studied this stuff most of their lives.

 

http://en.wikipedia.org/wiki/Carolina_Bay

 

Theories of Origin

 

 

 

More than a dozen bays are shown in this photo in southeastern North Carolina. Several are cleared and drained for farming.

Theories of the origin of the Carolina bays fall into two major categories: that these features were created by forces within the Earth, or that they were gouged by an astronomical event or set of events.

[edit]Geomorphology

Various geomorphological theories 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 theory 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 siliclastic karst by solution of subsurface material during glacial sealevel lowstands and later modification of these depressions by periodic eolian and lacustrine processes.

Various proposals that they were either directly or indirectly created by a meteorite shower or exploding comet are disputed by many scientists for an apparent lack of extraterrestrial material, absence of shocked quartz and "bedrock" deformation associated with larger bays, and extremely low ratio of depth to diameter of the larger bays. More information on these theories can be found at: Carolina Bays.

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. [2]. 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 Wisconsin glaciation between 15,000 and 40,000 years and 70,000 to 80,000 years BP [3]. 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 Wisconsin glaciation as reconstructed from Pleistocene parabolic dunes, a time when the shape of the Carolina bays was being modified [4].

[edit]Impact event

The cometary impact theory of the origin of the bays was popular among earth scientists of the 1930s and 40s. It said that they were the result of a low density comet exploding above or impacting with the Laurentide ice sheet about 12,900 years ago.[1]

New hypotheses arose again in the 1980s and 1990s, spurred on by various attention to impacts such as the Tunguska event, Cretaceous–Tertiary extinction event and a theorized link to the unsolved scientific mystery of the Younger Dryas event. Impact geologists determined the depressions are too shallow to be impact features. Reports of magnetic anomalies turned out not to show consistency across the sites. There were no meteorite fragments or impact crater geologic structures. None of the necessary evidence for an impact was found. The conclusion was to reject the impact theory at the Carolina bays.[2]

[John L]

One thing: if the initial impact is somewhere else, or if the impactor detonates in the atmosphere, the residue, which would have created all those other craters/bays, would have far less kinetic energy, or size, and thus make smaller secondary craters. Did you watch the NatGeo video, which showed how small the many secondary craters were? You really should watch it if you haven't yet.

 

And there has been more than one major impactor event, because there are many examples of overlapping craters which are laid down over other, older ones.

 

Also, if you rely completely on Wikipedia, which is a site where people contribute to it, you will also tend to get whatever they wish to contribute. The global warming fiasco is a classic case in point, and Wikipedia still has not gotten over it.

[Moontanman]

I never said that oval craters were impossible or didn't happen but they are rare but the main thing you have to answer about the Carolina Bays is why there is no evidence of any impact at the sites, their ages are around 100,000 years old not a few thousand and there is no shocked quartz or any other mineral, no evidence of any extraterrestrial material associated with the bays, core samples do not indicate they were once deeper and filed with sediment. You show all the triangulation in the world but the fact remains there is no evidence they were caused by impacts, none, shape alone does not a crater make and incredulity about aeolian and water explainations do not make them invalid.

 

I had to go no further than wiki to find the explanation that was given me by local experts who have studied this stuff most of their lives.

 

http://en.wikipedia.org/wiki/Carolina_Bay

 

Theories of Origin

 

 

 

More than a dozen bays are shown in this photo in southeastern North Carolina. Several are cleared and drained for farming.

Theories of the origin of the Carolina bays fall into two major categories: that these features were created by forces within the Earth, or that they were gouged by an astronomical event or set of events.

[edit]Geomorphology

Various geomorphological theories 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 theory 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 siliclastic karst by solution of subsurface material during glacial sealevel lowstands and later modification of these depressions by periodic eolian and lacustrine processes.

Various proposals that they were either directly or indirectly created by a meteorite shower or exploding comet are disputed by many scientists for an apparent lack of extraterrestrial material, absence of shocked quartz and "bedrock" deformation associated with larger bays, and extremely low ratio of depth to diameter of the larger bays. More information on these theories can be found at: Carolina Bays.

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. [2]. 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 Wisconsin glaciation between 15,000 and 40,000 years and 70,000 to 80,000 years BP [3]. 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 Wisconsin glaciation as reconstructed from Pleistocene parabolic dunes, a time when the shape of the Carolina bays was being modified [4].

[edit]Impact event

The cometary impact theory of the origin of the bays was popular among earth scientists of the 1930s and 40s. It said that they were the result of a low density comet exploding above or impacting with the Laurentide ice sheet about 12,900 years ago.[1]

New hypotheses arose again in the 1980s and 1990s, spurred on by various attention to impacts such as the Tunguska event, Cretaceous–Tertiary extinction event and a theorized link to the unsolved scientific mystery of the Younger Dryas event. Impact geologists determined the depressions are too shallow to be impact features. Reports of magnetic anomalies turned out not to show consistency across the sites. There were no meteorite fragments or impact crater geologic structures. None of the necessary evidence for an impact was found. The conclusion was to reject the impact theory at the Carolina bays.[2]

 

And no, wiki is not my only source of information but this particular article was concise and to the point, here is another...

 

http://www.georgehoward.net/cbays.htm

 

Yes I agree that meteor impacts have probably had more influence on the Earth than we give them credit for but every impression in the ground is not a meteorite crater....

 

An impact that would generate so many craters should have had profound impact on the climate of the day and you are postulating that such oval impact craters were made by more than one impact? While oval craters are occasionally found 100,000's of thousands of them in a small area from more than one impact seems a bit of a stretch to me... especially when more likely causes are logically possible... and again, there is no evidence of impact at any of the bays, even the ones that are miles across....

Edited November 25, 2011 by Moontanman

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Currently, many scientists believe high pressure winds formed these structures, which would be impossible simply because of the circular nature of the structures. Strong winds can form sand dunes, but not circular structures of widely varied sizes, surrounded by elevated borders of sand; some with concentric circular structures within the same depression.

 

 

 

http://en.wikipedia.org/wiki/Carolina_Bay

 

 

 

In addition, the uniform direction of the long axis of the oval depressions is always aligned with the slope of the surrounding soils over wide areas, further demonstrating the impossibility of thousands of cosmic fragments impacting in the same direction or by strong jets of wind.

 

 

 

Google Earth LIDAR images and http://www.georgehoward.net/cbays.htm.

 

 

 

Over the past several years, teams of researchers have drilled holes in and around many of these depressions. Substantial amounts of hydrogen gas were measured emerging from the soil inside their borders and very little or none outside. This was the same result in similar depressions tested in the USA [North & South Carolina, Kansas, Nebraska], Russia, Ukraine and Africa. What I found more interesting was the fact that little or no hydrocarbons were found, yet, when some areas within these depressions were set on fire by lightening or man, the fires could burn over a relatively large area and appeared nearly invisible. This is a characteristic of hydrogen gas fueled fires, unlike the more colorful fires resulting from decayed vegetation gases or natural gas.

 

 

 

Water was also associated with hydrogen emissions in these depressions, which would be understandable since hydrogen is a reactive gas and can combine with oxides to form water [HOH]. In Africa, the existence of oasis water holes was considered to be evidence of hydrogen emissions. One oasis village had a well drilled in the hope of finding a source of pure water. The drillers were surprised to find 98% hydrogen. So they rigged up a hydrogen powered generator to supply the local village with electricity. When they asked the village chief what he wanted most from the new found electricity, he answered, “Refrigeration to make Ice Cream.”

 

 

 

NH2E.com

 

 

 

One possible answer to the evolution of a relatively flat plain becoming populated by circular depressions is based on the fact that hydrogen atoms are small enough to uniquely reside within the atoms and molecules of many other elements. Their presence creates no increase in apparent mass; only increased density. However, when stressed by earth tides, a result of our Moon's gravity, the hydrogen atoms can effuse from within the other elements and form hydrogen molecules between grain boundaries. This would expand a region inside Earth's crustal layers, then vent from its surface, then escape into space. This behavior of hydrogen is known in the materials industry as Hydrogen Embrittlement, a continuing threat to the strength of materials. This is especially common in drilling equipment utilized in deep wells, which are often saturated with hydrogen gas.

 

 

 

http://www.uni-saarland.de/fak8/wwm/research/phd_barnoush/hydrogen.pdf

 

Dr.-Ing. Afrooz Barnoush, December 1, 2011

 

 

 

I suggest that Carolina Bay type depressions appear to have been formed by hydrogen emissions which had a greater flow rate in the past. These emissions could have been substantial enough to expand the soils and elevate the surface level of the ground in a circular manner; a hydrogen bubble. If so, the elevated surface would eventually become weathered and exfoliated surface materials would be deposited around the elevated portion. Then, with a decrease in the flow rate of hydrogen emissions, the now eroded surface would deflate and become a circular or oval depression. This process has obviously been repeated several times within some depressions over extended periods of time.

 

 

 

Fact remains, the interiors of every Carolina Bay type structure tested by researchers are venting hydrogen and they are all surrounded by borders of previously exfoliated surface materials, usually sand. So I believe the origin of Carolina Bays type structures is the result of internal hydrogen emissions, sub-surface expansion, the weathering of expanded surfaces and subsequent deflation. If anyone has a better idea, I would appreciate their explanation.