Along the coastal regions of the eastern United States, a number of curiously-shaped ponds scatter the seaboard landscape. Known as the “Carolina bays”, these elliptical bodies of water appear as far south as Florida, all the way up to Maryland, where regional name also include the Maryland Basins or the Delmarva bays.
The bays have been a subject of debate, particularly in recent years, due to controversies that have arisen over their origins. These pock-marks (or “bagols” as they are sometimes called) have long been supposed to result from natural geomorphological processes that involve clastic formation in regions where limestone is prevalent, if not more general geological lacustrine processes (the formation of lakes, in other words).
However, another more controversial theory as to the formation of the bays involves the notion that they were created by scattered pieces from a massive impact event, which grazed the areas known as the Carolina bays following the primary impact. First proposed as far back as the 1940s, this idea is widely disputed due to a number of issues: namely, that no evidence that links meteors or other ejecta from a primary impact has been directly associated with the bays and their formation.
Although many believe the "impact theory" has been laid to rest, a new paper by Antonio Zamora titled “A model for the geomorphology of the Carolina Bays” has revived the idea, suggesting that new evidence could still support the theory of an impact of some sort.
In the paper, Zamora explains that the bays are the likely result of "shock liquefaction impact features" from massive ice boulders, which were literally blasted from the glacial ice sheet by a cosmic impact coinciding with the Younger Dryas event (this refers to a geological period occurring between 12,900 and 11,700 years BP, during which a sharp decline in temperatures occurred over most of North America during the end of the Pleistocene).
Relevant information from the article’s abstract gives us the following breakdown:
“Geometrical analysis of the Carolina Bays using Google Earth in combination with LiDAR data makes it possible to postulate that the bays formed as the result of impacts, rather than from eolian and lacustrine processes. The Carolina Bays are elliptical conic sections with width-to-length ratios averaging 0.58 that are radially oriented toward the Great Lakes region. The radial distribution of ejecta is one characteristic of impacts, and the width-to-length ratios of the ellipses correspond to cones inclined at approximately 35°, which is consistent with ballistic trajectories from the point of convergence.”
If, as Zamora's paper suggests, the bays were created by massive chunks of ice that were blasted skyward as a comet smashed into the Pleistocene ice sheets, it might explain why no evidence of meteors or other objects have been found at the bay areas themselves. It should be noted, however, that Optically Stimulated Luminescence (OSL) dating of sample areas around the rims of some of the Carolina bays, along with other data extracted from cores of sediments within the bays themselves, still suggests that some of the bay formations date back to at least 60,000 BP, which would make them far too old to have been created at the time of the Younger Dryas.
Zamora's article is featured in Geomorphology, Volume 282, 1 April 2017, Pages 209–216, and can be read online here.
This paper is interesting for a few reasons. Obviously, reviving the debate about what processes led to the formation of the Carolina bays is interesting enough. However, this article arrives on the heels of the publication of a similar paper in Nature, titled "Widespread platinum anomaly documented at the Younger Dryas onset in North American sedimentary sequences", which suggests that consistent detection of a platinum anomaly, both in geological strata and recovered from ice cores, presents evidence of a possible extraterrestrial impact that might have caused the Younger Dryas (I discussed the article, and some of its implications, over on my blog).
While a number of theories about what caused the Younger Dryas have been offered, there are two primary schools of thought: the first is the climatic interpretation, where deglaciation may have been the primary cause, possibly resulting in a massive flood which served as the primary catalyst for cooling temperatures. The other discipline holds that an impact, possibly involving a comet, struck the ice sheets over North America around 12,800 BP, resulting in the Younger Dryas.
There is an interesting point to be made about this apparent "divide" between the proponents of ancient climate change, and the "Impact Truthers". Quite simply, while there are some researchers who see it as a war of ideas (and ideologies), there are also plenty of good scientists, doing good work, which leads them to conclusions based on evidence, not ideology.
Let me give you an example.
Last year, a paper appeared in Southeastern Geology titled, "The Quaternary Evolution of Herndon Bay, a Carolina Bay on the Coastal Plain of North Carolina (USA): Implications for Paleoclimate and Oriented Lake Genesis." The authors were Christopher R. Moore, Mark J. Brooks, David J. Mallinson, Peter R. Parham, Andrew H. Ivester, and James K. Feathers. This group of researchers examined one of the bays located in eastern North Carolina, and the following excerpt summarizes the essence of their findings:
While many nuances of bay evolution remain to be re-fined, the evidence at Herndon Bay clearly supports the concept that Carolina bays represent a regional example of a globally-occurring phenomenon: They are wind-oriented lakes shaped primarily by lacustrine processes.
Sounds pretty definitely against the "impact" theory, right? That's because it is (also, I would like to give credit to Dr. Andy White at the University of South Carolina for posting about this on his blog last March, which brought it to my attention). That said, if one were to compare the authors of that paper with the list of contributors to the recent Nature paper addressing a platinum anomaly, we once again find Christopher R. Moore, Mark J. Brooks, Andrew H. Ivester, and James K. Feathers' names all turning up.
Why is this significant? Because while one paper (dealing with the Carolina bays and their formation) would seemingly detract from the Younger Dryas Impact hypothesis, the other (dealing with a Younger Dryas related platinum anomaly) does just the opposite, lending new potential evidence in support of an extraterrestrial source for the platinum: likely a comet or other space object colliding with Earth.
While the impact theory is still viewed unfavorably by much of the science community, there is good science being done to try and analyze this ancient mystery, and some of the findings are indeed in contrast to the academic community's accepted views about things. Further, many of the same researchers are contributing data that both supports, and detracts, from the impact theory, rather than simply catering to biases.
And that's good, because fundamentally, that's how science works... and eventually it may even help us crack this Younger Dryas nut before another comet smashes into Earth, and we have to start all over again.