At Cosmictusk.com there was a comment by Terry Egolf, which triggered an idea that I posted as a comment and that I post here as well.
For those who have never heard of them or would like to know more of the basics, see here.
This was an interesting and thought-provoking idea:
As George knows, I’m a YEC, so I immediately thought of a Genesis Flood-related process. Based on some work done by Emil Silvestru, an eminent karstologist, I imagined thermal decomposition of deeply buried limestones off the east coast releasing high pressure carbon dioxide into the upward-tilted aquifers underlying the coastal plain. As the lithostatic pressure lessened, gas bubbles expanded and broke through the impermeable rock strata and burst through the surface sediments. If this had occurred near the end of the recessional stage of the Flood, and while the coast was still under water, the flow off the land could have lengthened the craters in the direction of flow. Now THAT is what I call thinking outside the box! Non-uniformitarian catastrophism at its best. Heh.
…Your bubble hypothesis IS definitely out of the box, which alone says nothing for or against it.
When the waters receded, they would have done so at a less than glacial pace. Year to year, it would have been relatively difficult to see or measure. As the coastline receded, then at some point – and for a very long time – each bay would have been straddling the high and low tides. Not only would the bay have seen the incoming and outgoing tides, but wave action every minute or two.
It seems not possible that the waves would not have completely erased the sand rim of that at-risk bay, all 360° of it. I have spent much less time on beaches than you, a submariner, would have done, but I know that any competition between sand and waves is always won by the waves. The best we would see is a high tide sand dune. How that could turn into an ellipse I can’t see.
Nice try on that aspect, but I can’t see it working. Not if the solid surface were underwater. But it takes my mind to something else…
Your bubbling idea brings to mind the hydrate fields under the coastal waters.
THIS seems like something worth looking into. We have so far only a little understanding of hydrate “patches”. It is certain that the water pressure helps keep them from bubbling up, and what allows them to bubble up is a release of the pressure for whatever reason. So far, all the studies have been focused on hydrates currently under the water. If the coastal plain was at one time under water, then one would think that hydrates were underlying those areas, too. And since they do bubble up from time to time, it makes sense that they could bubble up under above-sea-level coastal plains, too.
You suggest they bubbled up while under water, but the transition from under water to dry land I don’t think is tenable. Therefore, perhaps considering that they might have bubbled up AFTER the land emerged may make more sense.
To widen our overall picture, let’s consider the New Madrid quakes of 1811-1812. One of the phenomena of those was what are termed “sand blows.” Here is a link to an image of sand blows in the New Madrid area: