This presentation describes the scientific exploration of a small Carolina Bay to obtain soil samples for dating and forensic analysis.
Arabia Bay in North Carolina. On August 16th, 2019, I participated in the exploration of Arabia Bay, which is located about 10 kilometers southeast of Raeford, North Carolina. The bay is adjacent to Arabia Road, from which it takes its name. The length of the bay is 390 meters, which is small compared to other Carolina Bays nearby.
The exploration became possible because Arabia Bay is being converted from farmland to wetland by Restoration Systems, LLC. George Howard, who is the co-founder and CEO of Restoration Systems, organized a meeting of scientists and researchers to conduct scientific investigations during the initial phase of the restoration of the bay.
This LiDAR image of Arabia Bay shows the well-defined rims that have defied erosion by wind and water for thousands of years. The shape of the bay conforms to the prototypical elliptical geometry of the Carolina Bays. The Glacier Ice Impact Hypothesis published in 2017 proposes that an extraterrestrial impact on the Laurentide Ice Sheet ejected chunks of glacier ice in ballistic trajectories, and that the secondary impacts of the ice chunks liquefied unconsolidated ground and created inclined conical cavities that became shallow elliptical bays by viscous relaxation. Experiments of ice impacts on a viscous surface have demonstrated that inclined conical cavities appear as ellipses when viewed from above, as shown in the inset figure. The satellite image of the same area shows the plowed fields in the center of the bay and the turkey farm buildings located outside of the bay.
The yellow circle has a diameter of 75 meters, which is approximately the size of the glacier ice boulder that made the bay. The width-to-length ratio of the bay indicates that the glacier ice projectile hit at an angle of approximately 43 degrees. Ballistic equations and laws relating energy to crater size estimate a launch speed of 3,230 meters per second, a flight time of 7.48 minutes, and an energy yield equivalent to 278 kilotons of TNT. The bay formed in 4.74 seconds.
We got together the day before to plan the excavation. Michael Davias described his LiDAR maps Michael Davias and George Howard checked GPS coordinates and LiDAR images while Chris Cottrell looked on before proceeding to the site. The excavation equipment and the crew were already on site when we arrived at 9 AM.
George Howard informed the Restoration Systems crew about the people who were coming to see the excavation. and then we still have about 30 minutes before we start fooling around. Micah Hanks and Jason Pentrail who are.. Micah is a blogger, you know, a podcaster about a lot of things, and Jason Pentrail joins his podcast on nothing but archeology, and they're just kind of interested in geomorphology and what was going on in this landscape 10 to 15 thousand years ago.
While the equipment was being moved to the dig site, Mr. Harris, the turkey farmer, came out and inquired about our project. The turkey farm has two silos with wood chips used to cover the floor of the building. I took a look inside the building.
Excavation started on the east rim of Arabia Bay. The objective was to dig deep enough to find the Younger Dryas Boundary and get soil samples above and below the line. George Howard monitored the depth and examined the layers on the walls of the trench. Micah Hanks and Jason Pentrail from the Seven Ages Research Associates arrived during the excavation of the east rim of the bay. George Howard explained the methodology for the excavation. This picture shows the layers encountered in the rim of the bay and the holes in the wall of the cavity from which the samples were taken. The measuring rod was used to document the depth of each sample. The bottom of the trench started to fill with water when the trench went below the water table.
The samples were catalogued, properly labeled and bagged. Each bag contained at least one kilogram of sample to allow multiple tests and to reserve some material for future use. Anything can happen when you are out in the field. We had to take a half-hour break inside our cars while a rainstorm passed by. We were glad when the sun came out. Fortunately, the soil in the Carolina Bays is very porous and the rain drained away quickly without leaving any mud puddles.
This exploration did something that had not been tried before for Carolina Bays, which was to dig at the apex of the bay. The apex is the location presumed to be the resting place of the ice boulder that made the bay. The place was marked with a stake using GPS coordinates.
The soil at the apex of the bay had four distinct layers. The top layer was dark from organic matter. A second layer was reddish brown and the third one was light gray. The fourth and deepest layer was bright yellow and completely saturated with water. Water flowed rapidly and the walls started to crumble.
Michael Davias examined the soil looking for rocks that might have been brought from Michigan by the glacier ice boulder, while George Howard monitored the excavation. The pile of soil shows the different colors of the layers of the bay. It was too dangerous to go down into the pit because the walls were collapsing, so samples from the bottom were brought in the scoop of the excavator for examination under safer conditions.
The deep unstable portion of the trench was filled with dirt and George went down to obtain samples from the wall. The excavation on the west rim of Arabia Bay was in the middle of a grove of pine trees that had been planted as a reforestation project. Chris Cottrell was in charge of labeling and logging the soil samples. The water table was reached sooner than on the east rim. The Younger Dryas Boundary was closer to the surface in the west rim than in the east rim of the bay.
I hope that this video has given you an idea of the hard work required for geological research. We had to protect ourselves from rain, hot weather, and insect bites while trying to accomplish our goal. A lot of hard work lies ahead for processing the samples.
Chris Cottrell will prepare the samples for analysis, and the samples will provide some answers about the origin of the Carolina Bays and help to guide future research. George Howard deserves a lot of credit for combining scientific research on the Carolina Bays with the land restoration work that will give us a greener planet.