The Delaware Geological Survey has published an online report that presents a compilation of chronologic information for coastal sedimentary deposits of the U.S. Atlantic and Pacific coasts, with additional information for sites on the Pacific coast of South America.
Titled Database of Quaternary Coastal Geochronologic Information for the Atlantic and Pacific Coasts of North America (additional information for sites in Peru and Chile), Open File Report Number 50 presents the results of research conducted over nearly 40 years by John F. Wehmiller, professor emeritus in UD’s Department of Geological Sciences; Vincent Pellerito, of URS Corp., Conshohocken, Pennsylvania, and formerly of both the Delaware Geological Survey and UD geological sciences; and numerous other colleagues both within and external to the DGS and the University of Delaware.
Open File Report No. 50 contains a variety of information related to the chronology and stratigraphy of over 1,000 collection sites from coastal sedimentary units, including approximately 150 from Delaware, most of Quaternary age (~ < 2 million years).
This information includes data obtained by various radiometric methods such as radiocarbon and uranium-series dating, plus a large body of data based on the use of amino acid racemization (AAR), a method of dating first developed in the late 1960s at the Carnegie Institution of Washington.
Wehmiller and colleagues have used and refined AAR methods for numerous applications, most of which provide insight into the geologic evolution of coastal landforms throughout the Quaternary.
Knowledge of the age of sedimentary units assists in mapping of surface and subsurface units, establishing the chronology of sea level histories linked to Quaternary climate change, understanding of deformation rates in regions of tectonic activity, and reconstructing ancient climate when combined with paleontologic information.
In addition, much of this research has helped to understand the geochemical intricacies of the AAR dating method, which itself remains experimental in nature.
Open File Report No. 50 brings together a variety of information beyond the site- and sample-specific analytical data. Supplementary files containing relevant publications, maps, laboratory and field notes, and supporting geochemical information are also available.
Links to online maps, files hosted on UDSpace and the National Oceanographic and Atmospheric Administration (NOAA) Paleoclimatology Site are also provided.
The database remains a work in progress and all updates to the database or supplemental files will be identified appropriately.
DGS Open File Report No. 50 is part of the Delaware Geological Survey’s ongoing mission to understand geologic and hydrologic systems and to advise, inform, and educate Delawareans about the results of such investigations for use in issues regarding surface and groundwater resources, agriculture, economic development, land-use planning, environmental protection, resource evaluation, engineering applications, hazard identification and mitigation, and recreation.
It is available online -- with all supporting supplements and instructions for use -- from the DGS webpage.