AN EVOLVING AMINOSTRATIGRAPHIC DATABASE FOR QUATERNARY COASTAL DEPOSITS

Over the past four decades, amino acid racemization (AAR) geochronology has found applications in numerous studies of coastal deposits world-wide, in order to reconstruct glacial, tectonic, or relative sea-level histories. Although there exist hundreds of publications resulting from these studies, only recently has there been an organized effort to compile data (analytical, locality, sample, and interpreted) for these studies into a community database. During 2010-2011, two workshops were held to initiate efforts toward data preservation, with the result being an evolving database at http://www.ncdc.noaa.gov/paleo/aar.html. Results from four active US laboratories are currently included, with each file containing raw or processed analytical data and descriptive metadata. Data files represent publications from 1971 through 2010.

The University of Delaware Aminostratigraphy Database was initially developed in 2004 with the goal of gathering dozens of separate data files (generated in a variety of file formats since 1979) into a common structure (Pellerito, 2004). This database, using MS Access® software, has six levels ranging from a unique locality identifier through sample details and down to results unique to a single chromatographic analysis, thereby allowing for multiple instrumental runs. Over 2800 collection sites are now recorded, many located to within 100 m using Google Earth, while others have larger uncertainties because of their collection histories. Not all sites have AAR data, but sites for which relevant or independent geochronologic information exist are also included in the database, with appropriate citations. For sites within the US, results are grouped according to USGS 1:100,000 topographic sheets to facilitate searches for all data within a particular region, and also directly linked to ArcGis maps. The database front-end permits searches based on a variety of criteria, with outputs being generated in a simple spreadsheet with as many as 35 columns of information about each sample. Information about sample archival storage is also maintained in the database, as in most cases the original collection sites can no longer be revisited. Documentation of data, collections, and specimens will become an ever more important component of AAR and other Quaternary geochronologic studies.