Abstract - The Younger Dryas Impact Study

The events precipitating the dramatic, millennial long climatic cooling known as the Younger Dryas, that occurred approximately 13,000 years ago remain a mystery. Recent evidence suggests an extraterrestrial impact on the Laurentide ice sheet may have provided the trigger for the massive influx of fresh glacial melt water posited to have flooded the North Atlantic and shut down the Thermohaline circulation that moderates climate in the northern hemisphere.

The apparent absence of an easily identified impact crater has made the search for evidence of an impact, in the form of extraterrestrial markers embedded in the Earth’s sedimentary record, a critical element of the research.

Association of an impact with coincident disappearance or reduction in the numbers of extant megafauna and human occupants of North America has suggested a strategy for the search for evidence of the impact. Evidence of an impact responsible for initiating the onset of the, the ultimate disappearance of megafauna species and decline in human populations should be present at the sedimentary boundary (YDB) separating the Younger Dryas from the preceding Bolling-Allerod at a depth corresponding to 12,900 years before present.

Some of these evidential markers (magnetic spherules) are relatively easy to extract and identify while others (nanodiamonds and fullerenes) require great care, expensive instrumentation and considerable training. Fortunately, the vessels containing the more challenging markers (carbon spherules) can be identified and extracted during the soil processing for magnetic spherules. The processing of YDB soil samples for extraterrestrial impact markers can provide students an opportunity to participate in the scientific process while performing valuable research; engaging them in the essential process of discovery whose experience motivates young adults to pursue scientific careers. They will also gain valuable training and experience-collecting soil samples, using scientific diagnostic tools such as magnetic susceptibility meters, global positioning devices (GPS) and microscopes; as well as an appreciation of the importance of more sophisticated soil analysis techniques such as Transmission Electron Microscopy and X-Ray Crystallography.

The proposed research project to be conducted at Elizabeth City State University’s center for Environmental Remote Sensing includes an investigation of local lacustrian depressions known to harbor impact markers and whose stratigraphy may reveal a clearer understanding of the processes that shaped the coastal topography during the Younger Dryas. The research will be carried out using a combination of Ground Penetrating RADAR (GPR) and sample coring to probe the subsurface deposits of selected depressions.