Major- and Trace-Element Concentrations in Soils from Northern California: Results from the Geochemical Landscapes Project Pilot Study

The regional-scale California study was designed to represent more detailed, higher resolution geochemical investigations in a region of particular interest that was identified from the low-sample-density continental-scale survey. A 20,000-km area of northern California (fig. 1), representing a wide variety of topography, climate, and ecoregions, was chosen for the regional-scale pilot study. This study area also contains diverse geology and soil types and supports a wide range of land uses including agriculture in the Sacramento Valley, forested areas in portions of the Sierra Nevada, and urban/suburban centers such as Sacramento, Davis, and Stockton.

Also of interest are potential effects on soil geochemistry from historical hard rock and placer gold mining in the foothills of the Sierra Nevada, historical mercury mining in the Coast Range, and mining of base-metal sulfide deposits in the Klamath Mountains to the north. This report presents the major- and trace-element concentrations from the regional-scale soil geochemical survey in northern California. [Summary provided by the U.S. Geological Survey.]