The first aerial photo of Carolina Bays, taken in 1930.
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As I was scanning North Carolina, I saw something that brought to mind a term that I haven't heard since I was majoring in geology 40 years ago - Carolina Bays. (An achievment in itself for someone who often can't remember where the car keys are). I typed the phrase into Google, and got multiple hits - it really was the term to describe what I was looking at. One interesting thing about these oriented oval structures is that geologists are still not sure of their origin. Their signifigance wasn't discovered until the 1930's when aerial photography revealed their true nature. I think the strongest hypothesis is that they are of extra-terrestrial origin, caused by a comet nucleus that broke up in the atmosphere, scattering pieces that gouged out depressions which are all oriented in a NW-SE direction. But there are other theories, some plausible, some unlikely. Click the "web page" links to take you to further discussion of the Carolina Bays. web page 1 web page 2 web page 3 web page 4
web page 5
For more information about this and similar phenomena, go to http://www.perigeezero.org

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Orientation of the bays points back to a common point of origin to the northwest.

And see Obie's earlier post on the same topic, using the Algonkian word "pocosin", the older name for Carolina bays.

The attached placemark is at Poquoson, Virginia, but if there were a pocosin here, it has likely been drained for development.

Sketch of a cross-section exposed by a road cut of a bay in Virginia.
Included here are more placemarks in NC, SC, GA, and VA. Much has been lost due to rapid development, though sub-surface evidence remains.

Neat that you can see the circular impact structure in Lake Waccamaw (Ithe largest).

These lakes look very similar in many ways to the Carolina Bays of the SE U.S. They are located in Southwest Australia about 180 miles SE of Perth. I have arbitrarily named groups of them for easier analysis. There are others outside of these groups.

One hypothesis about the formation of the Carolina Bays proposes that they formed such large ovals in some areas, not just because of a strike by pieces of a disintegrating comet fragments. The resulting lakes were so large because the glowing hot material, coming in at a steep angle, struck a boggy area and the steam created literally exploded large holes out of the soft wet substrate. Strikes on drier ground had much less effect. The Australian area is also an old river course. Could the same processes be in effect here? Any geologist or geomorphologist with knowledge of the area could be of great help here. I haven't found much by googling so far.

Here is yet another reference to oriented lakes, possibly of meteoric origin, in South Africa posted by Cintos . He has created overlays showing the orientation of the lakes. Also check out the links below his name in his signature for posts about other oriented structures.

Hill I read this before but this thread has more complete info thant many others www

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I think the strongest hypothesis is that they are of extra-terrestrial origin, caused by a comet nucleus that broke up in the atmosphere,

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Me too I support this hypothesis

Then there are these Arctic lakes that seem to have a different, yet still not fully explained origin. They have been placemarked a number of times. They display a similar orientation and a tendency to be more polygon than oval.
More here.

OK, I'm intrigued. The Bay you marked in the Bon Air quadrangle in VA is in my backyard. A search turned up the paper that the diagram you posted is from (BTW, that diagram isn't showing a cross section, it's showing a road cut that contains an area of gravel.)

Anyway, I'm going to continue searching for others, but I'm surprised a this particular location being designated as a bay, when it was supposedly created in the 1980s when they built the expressway. Look at a topo of the area (topozone.com) and see that the pond is considered new. I don't know if anyone has done any cores to be able to do a stratigraphy study on it - I will say that from my backyard, it appears rather man-made.

--Bonnie

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Ice Age Ends Smashingly: Did a comet blow up over eastern Canada?

Sid Perkins for Science News

Evidence unearthed at more than two dozen sites across North America suggests that an extraterrestrial object exploded in Earth's atmosphere above Canada about 12,900 years ago, just as the climate was warming at the end of the last ice age. The explosion sparked immense wildfires, devastated North America's ecosystems and prehistoric cultures, and triggered a millennium-long cold spell, scientists say.



IT'S IN THERE. A layer of carbon-rich sediment (arrow) found here at Murray Springs, Ariz., and elsewhere across North America, provides evidence that an extraterrestrial object blew up over Canada 12,900 years ago. The hallmarks include lumps of glasslike carbon (top), carbon spherules (middle, in cross section), and magnetic grains rich in iridium (bottom).
West; (middle inset): Cannon Microprobe

At sites stretching from California to the Carolinas and as far north as Alberta and Saskatchewan�many of which were home to prehistoric people of the Clovis culture�researchers have long noted an enigmatic layer of carbon-rich sediment that was laid down nearly 13 millennia ago. "Clovis artifacts are never found above this black mat," says Allen West, a geophysicist with Geoscience Consulting in Dewey, Ariz. The layer, typically a few millimeters thick, lies between older, underlying strata that are chock-full of mammoth bones and younger, fossilfree sediments immediately above, he notes.

New analyses of samples taken from 26 of those sites reveal several hallmarks of an extraterrestrial object's impact, West and his colleagues reported at the spring meeting of the American Geophysical Union in Acapulco, Mexico.

Samples from the base of the black mat yield most of the clues to its extraterrestrial origin, says Richard B. Firestone, West's coworker and a nuclear physicist at the Lawrence Berkeley (Calif.) National Laboratory. Some of the particles there are small, magnetic grains of material with higher proportions of iridium than are found in Earth's crust, he notes.

Also in the mat's base are tiny lumps of glasslike carbon that probably formed from molten droplets of the element. These lumps, as well as little spheres of carbon with a different microstructure, contain nanoscale diamonds formed under intense pressure.

A host of unusual geological features, collectively known as Carolina Bays, hints at the cataclysm's location, says team member George A. Howard, a wetland manager at Restoration Systems, an environmental-restoration firm in Raleigh, N.C. Around 1 million of these elliptical, sand-rimmed depressions, measuring between 50 meters and 11 kilometers across, scar the landscape from New Jersey to Florida. In samples taken from 15 of the features, Howard and his colleagues found iridium-rich magnetic grains and carbon spherules with tiny diamond fragments similar to those found at Clovis archaeological sites.

The long axes of the great majority of the Carolina Bays point toward locations near the Great Lakes and in Canada�a hint that the extraterrestrial object disintegrated over those locales, says Howard.

Because scientists "haven't discovered a large, smoking hole" left by the event, the object that blew up in the atmosphere probably was a comet, says West.

Heat from the event would have set off wildfires across the continent, the scientists suggest. The heat and shock from the explosion probably broke up portions of the ice sheet smothering eastern Canada at the time, they add. The flood of fresh water into the North Atlantic that resulted would have interrupted ocean currents that bring warmth to the region, and thick clouds of smoke and soot in the air would have intensified cooling across the Northern Hemisphere.

The inferred date of the event matches the beginning of a 1,200-year-long cold spell that geologists call the Younger Dryas, which in its first few decades saw temperatures in the Northern Hemisphere drop as much as 10�C.

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Also see this post.

And from another source about the site:

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"People first arrived in this area 11,000 years ago. They belonged to what we now call the Clovis Culture and were the earliest known people to have inhabited North America. Named after the distinctive and beautifully crafted Clovis spear points they made, they were expert hunters of the large mammals of the Ice Age."

"These Clovis activity areas were uncovered directly under the Clanton Clay deposit, or the"black mat" which was laid down relatively rapidly and is primarily organic in composition. The origin of this black mat is a subject of debate, but its occurrence immediately over the Clovis sites has made absolute dates possible."

"The Clovis people were big game hunters who were always on the move following such game as the mammoth, mastodon, horse, bison, and tapir during the close of the last ice age. Their dependence on this now extinct mega fauna characterized their culture and was so complete, that one theory proposes the people of this culture may have actually contributed to the extinction of these animals by over hunting. In any case, the extinction of the game caused corresponding shifts in the life style and survival strategies of humans, and gave rise to the next cultural episode called the Archaic Period. "

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Emphasis mine... Source.

EDIT: Added a news conference about the comet hit from YouTube