Skip to main content
U.S. flag

An official website of the United States government

Geochemical and mineralogical maps, with interpretation, for soils of the conterminous United States

April 25, 2019

Between 2007 and 2013, the U.S. Geological Survey conducted a low-density (1 site per 1,600 square kilometers, 4,857 sites) geochemical and mineralogical survey of soils in the conterminous United States. The sampling protocol for the national-scale survey included, at each site, a sample from a depth of 0 to 5 centimeters, a composite of the soil A horizon, and a deeper sample from the soil C horizon or, if the top of the C horizon was at a depth greater than 1 meter, a sample from a depth of approximately 80–100 centimeters. The <2-millimeter fraction of each sample was analyzed for a suite of 45 major and trace elements by methods that yield the total or near-total elemental concentration. The major mineralogical components in the samples from the soil A and C horizons were determined by a quantitative X-ray diffraction method using Rietveld refinement. This report presents all the maps and statistical information for each determined element and mineral along with an interpretive section discussing the possible processes that caused the observed national-scale geochemical and mineralogical patterns. Most often, the geochemical and mineralogical patterns reflect the composition of the underlying soil parent material with some modifications caused by leaching of the more mobile elements (for example, calcium and sodium) in the humid areas of the country.

Citation Information

Publication Year 2019
Title Geochemical and mineralogical maps, with interpretation, for soils of the conterminous United States
DOI 10.3133/sir20175118
Authors David B. Smith, Federico Solano, Laurel G. Woodruff, William F. Cannon, Karl J. Ellefsen
Publication Type Report
Publication Subtype USGS Numbered Series
Series Title Scientific Investigations Report
Series Number 2017-5118
Index ID sir20175118
Record Source USGS Publications Warehouse
USGS Organization Central Mineral and Environmental Resources Science Center