Strange Impacts From Long Ago

A couple of mysteries for us to consider: Please share your thoughts and additional information!

1. Carolina Bays:

"Carolina bays are elliptical depressions concentrated along the Atlantic seaboard within coastal Delaware, Maryland, New Jersey, North Carolina, South Carolina, Virginia, Georgia, and northcentral Florida (Prouty 1952, Kaczorowski 1977). In Maryland, they are called Maryland Basins (Rasmussen and Slaughter 1955).
Other landform depressions, not widely accepted as Carolina bays, are found within the northern Gulf of Mexico coastal plain in southeast Mississippi and Alabama, where they are known as either Grady ponds or Citronelle ponds (Otvos 1976, Folkerts 1997). Carolina bays vary in size from one to several thousand acres. About 500,000 of them are present in the classic area of the Atlantic Coastal Plain, often in groups, with each bay invariably aligned in a northwest-southeast direction...

"...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"

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


2. Younger Dryas impact hypothesis

"The Younger Dryas impact hypothesis or Clovis comet hypothesis was the hypothesized large air burst or earth impact of an object or objects from outer space that initiated the Younger Dryas cold period about 12,900 BP calibrated (10,900 BP uncalibrated).[1]
One scenario proposes that an air burst and/or earth impact with a rare swarm of carbonaceous chondrites or comets set vast areas of the North American continent on fire, causing the extinction of most of the large animals in North America and the demise of the North American Clovis culture at the end of the last glacial period.[2] This swarm would have exploded above or even into the Laurentide Ice Sheet north of the Great Lakes. An airburst would have been similar to but many orders of magnitude larger than the Tunguska event of 1908. Animal and human life not directly killed by the blast or the resulting coast to coast wildfires would have starved on the burned surface of the continent.

The scenario has been the subject of criticism and doubts. Impact specialists have studied the claim and concluded in 2010 that there never was such an impact, in particular because various physical signs of such an impact cannot be found.[3] The evidence for the event has been thoroughly dismissed, and the hypothesis is no longer considered viable in the scientific community.[4]"

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