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A national-scale geochemical and mineralogical survey of soils of the conterminous United States

March 26, 2011

In 2007, the US Geological Survey initiated a low-density (1 site per 1600 km2, c. 4800 sites) geochemical and mineralogical survey of soils of the conterminous USA. The ideal sampling protocol at each site includes a sample from 0–5 cm depth, a composite of the soil A horizon, and a sample from the soil C horizon. The <2-mm fraction of each sample is analyzed for Al, Ca, Fe, K, Mg, Na, S, Ti, Ag, Ba, Be, Bi, Cd, Ce, Co, Cr, Cs, Cu, Ga, In, La, Li, Mn, Mo, Nb, Ni, P, Pb, Rb, Sb, Sc, Sn, Sr, Te, Th, Tl, U, V, W, Y and Zn by inductively coupled plasma-mass spectrometry and inductively coupled plasma-atomic emission spectrometry following a near-total digestion in a mixture of HCl, HNO3, HClO4 and HF. Separate methods are used for As, Hg, Se and total C on this same size fraction. The major mineralogical components are determined by a quantitative X-ray diffraction method. Sampling was completed in 2010 with chemical and mineralogical analysis currently underway. Preliminary results for a swath from the central USA to Florida clearly show the effects of soil parent material and climate on the chemical and mineralogical composition of soils. A sample archive will be established and made available for future investigations.

Citation Information

Publication Year 2011
Title A national-scale geochemical and mineralogical survey of soils of the conterminous United States
DOI 10.1016/j.apgeochem.2011.03.116
Authors David B. Smith, William F. Cannon, Laurel G. Woodruff
Publication Type Article
Publication Subtype Journal Article
Series Title Applied Geochemistry
Index ID 70227299
Record Source USGS Publications Warehouse
USGS Organization Central Mineral and Environmental Resources Science Center; Eastern Mineral and Environmental Resources Science Center