This CD-ROM contains both the National Geochronological Data Base [NGDB] and the Natural Radioelement Data Base [NRDB]. Supporting location, geologic, and reference information is provided for both data bases. The NGDB is a compilation of more than 30,000 individual published Pb-alpha, fission-track, K-Ar, Rb-Sr, U-Th-Pb, and Sm-Nd rock and mineral ages reported on approximately 18,000 dated samples from the United States. A program is provided to search the data files by latitude and longitude, state, analytical method, and age range. The NGDB is provided as quote-comma delimited files that can be entered into most commercial spreadsheet programs. The NRDB gives gamma-ray spectrometric analyses of the natural radioelements (U, Th, and K) for more than 8500 whole-rock samples obtained under the USGS Natural Radioelement Distribution Project. A program is provided to search the data files by state, keyword, U content, Th content, and K content.
Additional publication details
USGS Numbered Series
National geochronological and natural radioelement data bases
The Survey ;
For sale by USGS Distribution Branch],