Northeastern Section - 49th Annual Meeting (23–25 March)

Paper No. 7
Presentation Time: 10:20 AM


WEHMILLER, J.F., Department of Geological Sciences, College of Earth, Ocean, and Environment, University of Delaware, 103 Penny Hall, Newark, DE 19716 and PELLERITO, Vincent, 650 Brooke Road, B15, Glenside, PA 19038,

Amino acid racemization (AAR) geochronology is one of many tools employed in Quaternary stratigraphic and geomorphic studies conducted world-wide over the past forty+ years. Numerous publications related to these studies exist, most being identifiable using standard bibliographic search engines. Nevertheless, there are clear needs to develop searchable databases that record collection locations, data, references, and interpreted results, not only for AAR but for other similar geochronologic information (radiocarbon, OSL, U-series, etc.). For the AAR community, this effort is just underway using the NOAA World Data Center site as a host for analytical data obtained by numerous labs since the early 1970’s (

The University of Delaware AAR Database (using MS Access® ) was developed over 10 years ago in order to organize dozens of separate data files (generated in a variety of formats since the mid-1970’s) into a common structure (Pellerito, 2004). The database has a “back end” containing six levels beginning with a unique locality identifier, then collection descriptions (i.e., bulk samples or bags of multiple individual specimens), individual samples (i.e., single shells), then laboratory data and results unique to a single analysis, thereby allowing the recording of multiple instrumental runs. The uncertainty in the location of each collection site is estimated using field notes, topographic maps, and Google Earth; uncertainties range from <10 m in some cases to >>1000 m in others, especially older collections or those obtained from museums. Over 2800 collection sites are now documented in our database; those within the US are grouped by relevant USGS 1:100,000 topographic sheets to facilitate data searching. Not all sites have AAR data, but they are included because of relevant independent chronologic information. The “front end” of the database allows searching using multiple criteria (map sheet, genus, latitude/longitude, etc.) and permits simple statistical outputs (means, standard deviations) for individual or groups of localities. The current storage location of analyzed samples is also recorded, as future collections may not be possible. Database outputs can be easily transferred to online ArcGIS for public viewing (e.g.

  • Wehmiller digital geoscience NE GSA 2014.pdf (750.7 kB)