The National Geochemical Survey - Database and Documentation

The USGS, in collaboration with other federal and state government agencies,
industry, and academia, is conducting the National Geochemical Survey (NGS) to
produce a body of geochemical data for the United States based primarily on
stream sediments, analyzed using a consistent set of methods. These data will
compose a complete, national-scale geochemical coverage of the US, and will
enable construction of geochemical maps, refine estimates of baseline
concentrations of chemical elements in the sampled media, and provide context
for a wide variety of studies in the geological and environmental sciences.
The goal of the NGS is to analyze at least one stream-sediment sample in every
289 km2 area by a single set of analytical methods across the entire nation,
with other solid sample media substituted where necessary. The NGS incorporates
geochemical data from a variety of sources, including existing analyses in USGS
databases, reanalyses of samples in USGS archives, and analyses of newly
collected samples. At the present time, the NGS includes data covering ~71% of
the land area of the US, including samples in all 50 states.

This version of the online report provides complete access to NGS data,
describes the history of the project, the methodology used, and presents
preliminary geochemical maps for all analyzed elements. Future editions of this
and other related reports will include the results of analysis of variance
studies, as well as interpretive products related to the NGS data.

[Summary provided the USGS.]