The North American Soil Geochemical Landscapes Project, funded by the USGS Mineral Resources Program, will have crews sampling in Arizona and 14 other states this summer. An update from David Smith in the program this afternoon provided these details: "This project was established in collaboration with the Geological Survey of Canada and the Mexican Geological Survey with its long-term goals to (1) produce a soil geochemical database for the continent of North America, (2) interpret the observed geochemical patterns in terms of process, and (3) establish a soil sample archive for future investigators. We have selected 13,596 sites for the continent using a generalized random tessellation stratified design. This represents a density of approximately 1 site per 1,600 square kilometers, with 5,813 sites falling within the US. We officially began sampling in 2007 after a 3-year pilot phase. The results of this pilot phase were published as 21 papers in a special issue of the journal Applied Geochemistry in August 2009. The 2010 field season should mark the completion of sampling in the conterminous US (4,871 sites)." [right, map of arsenic distribution in soils and other surficial materials of the conterminous United States based on 1,323 sample localities as represented by the black dots. Credit, USGS]
The states that will be sampled this summer are AZ, CA, IA, IL, IN, KY, MI, NC, OH, OR, TN, TX, VA, WA, and WI.