The Carolina Bays are shallow elliptical depressions with raised rims (Fig. 1). Some of the depressions are filled with water, but most are wetlands that are rich in biodiversity (Wikipedia).
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| Figure 1: Carolina Bays located in North Carolina. |
According to Wikipedia, there are about 500,000 of these structures found along the east coast and they range in size from 1 to several thousand acres. All of the structures are located in a general northwest to southeast orientation, but the long axes systematically rotate more westward moving North. The age of the structures are still debated, but based on several lines of evidence are considered to predate the start of the Holocene period no more than a hundred thousand years.
There are two proposed origins of the Carolina Bays. The first origin is considered to be geomorphologically created due to various processes. One major hypothesis is that these structures were formed from the dissolution of subsurface material and then later modified by a combination of eolian and lacustrine processes. The second origin is considered to be of an extraterrestrial impact. This hypothesis was widely accepted in the 1950's, however, after more research, this hypothesis did not hold up well because of the lack of impact evidence (e.g., too shallow and no meteorite fragments).
I have to admit that I am having trouble following the resurrection of the impact theory. I will try to explain it as best as possible below.
The impact hypothesis had been resurrected in 2009 after the Younger Dryas impact hypothesis by Richard Firestone in 2007 which he claimed was caused by an extraterrestrial comet airburst. According to Richard Firestone, the Carolina Bays were created from the shockwave of the impact. This hypothesis has been rejected by the scientific community because Richard Firestone evidence for an impact does not hold up. There is also the question of not finding a crater as well as Carolina Bays being of different age and therefore not created from a single event.
The latest hypothesis is that the Carolina Bays were made by impacts of ice that were secondary projectiles by an extraterrestrial impact on a glacier. However, I am not sure how this hypothesis answers the questions of no impact crater and the different ages of the Carolina Bays from before.
Here are some websites. The information I have written about were paraphrashed from these websites:
http://www.ancient-origins.net/news-science-space/carolina-bays-and-destruction-north-america-004458
http://www.scientificpsychic.com/etc/carolina-bays/origin-of-carolina-bays.html
https://en.wikipedia.org/wiki/Carolina_bay
