Summer 2009
THE CAROLINA BAYS: AN INVESTIGATION OF NORTH AMERICA’S POST LAST- GLACIAL MAXIMUM ENVIRONMENT (LGM)
Members: LaEsha Barnes (MVSU), Cedric Hall (ECSU)
Mentor: Dr. Dewayne Branch, Dr. Malcolm LeCompte
Keywords: katabatic winds, periglacial, Carolina Bay, nano diamond, carbon spherule, Ground Penetrating RADAR, slurry, epoch, stratigraphy

Buried beneath the East Antarctic Ice Sheet is a mountain range similar to the European Alps whose age estimates range from 35 to 500 million years. Expeditions during the International Polar Year are seeking to reveal the sub-glacial topography of the range and obtain hints to solve the mystery of their formation. The tools they are using include a combination of ice-core samples and ice penetrating RADAR.

During the Last Glacial Maximum, North America’s Laurentide Ice Sheet, reached its maximum extent approximately 20,000 years ago. Its south-easternmost margin penetrated deeply into Pennsylvania. There is no evidence that this or other glaciations went further, but it is believed that evidence for the harsh climatic conditions that prevailed during each glacial episode can be seen in topographical features that remain visible far to the South. Prominent among the features often attributed to glacial climate are numerous elliptically shaped, shallow depressions called collectively Carolina Bays, hypothesized to have been formed by “blow outs” of loose sediment by the strong, sustained winds characteristic of glacial epochs.

Approximately13,000 years ago, the Laurentide Ice Sheet’s retreat was interrupted by a return to glacial climatic conditions that persisted for over 1,000 years. The events precipitating the dramatic, millennial long climatic cooling, known as the Younger Dryas, remain both a mystery and the subject of debate. It has recently been hypothesized that a fragmented comet or asteroid might have simultaneously initiated the YD and formed the Carolina Bays. However, Carbon 14 dating and pollen analysis indicates an earlier genesis. While this research does indicate the bays were formed during prior glacial epochs, the bays also appear to be repositories of a significant amount of materiel considered evidence of an extraterrestrial impact including carbon and magnetic spherules and nanodiamonds.

If created during or before the LGM, the bays would have experienced episodic post-formation modification due to cold, dry, windy periods alternating with warm, moist and calmer climatic conditions. In this event, Carolina Bays would episodically fill with wind-blown or water-borne sediment or water.

To understand the processes that created the bays, it is helpful to probe their interior structure. Analogous to the Gamburtsev mountain research, sedimentary core samples and a ground penetrating RADAR survey were used to probe the interior of the bay to collect evidence consistent with either the terrestrial or extraterrestrial formation theory.