Publications National Geochemical Atlases

National Geochemical Atlases

NATIONAL GEOCHEMICAL ATLASES 

The IUGS Commission on Global Geochemical Baselines, apart from its main objective, which is the establishment of the Global Geochemical Reference Network, according to standardised methods of sampling, sample preparation, chemical analysis and quality control, promotes the national regional geochemical mapping and the free public availability of the analytical results, geochemical maps and geochemical atlases.  In this web page you will find national atlases that meet these conditions.  For a list of national geochemical atlases and surveys consult the dedicated Geochemical Atlases web page of the Association of Applied Geochemists.

 

  

Australia

Contact: Patrice de Caritat, Patrice.DeCaritat@ga.gov.au

 

The Geochemical Atlas of Australia was completed in 2011 and provides data on 68 mineral elements in sediment samples which were gathered from 1315 sites in 1186 catchment basins across Australia as part of Geoscience Australia's National Geochemical Survey of Australia project.

 

 

At each site two depth intervals were sampled and two grain size fractions were separated from the samples.  The shallower sample was from up to 10 cm below the surface (Top Outlet Sediment, TOS) and the deeper sample was from 60 to 80 cm below the surface on average (Bottom Outlet Sediment, BOS).  For each depth, the coarse (<2 mm) and fine (<75 µm) fractions were used for chemical assays.  The samples were prepared and analysed for up to 68 chemical elements using a range of techniques which yielded Total, Aqua Regia soluble and Mobile Metal Ion™ soluble concentrations.  Additionally, a bulk split was used for the determination of bulk soil properties.

 

 

The Geochemical Atlas of Australia are available for downloading from the website of Geoscience Australia

[http://www.ga.gov.au/about/projects/resources/national-geochemical-survey/atlas]

 

 

Caritat, P. de, Cooper, M., 2011. National Geochemical Survey of Australia: The Geochemical Atlas of Australia. Geoscience Australia Record 2011/20, 557 pp. (2 Volumes);  http://www.ga.gov.au/about/projects/resources/national-geochemical-survey.

 

 

North America

Contacts: (1) U.S.A.:  David B. Smith, dsmith@usgs.gov; (2) Mexico:  Francisco Moreira Rivera, fmoreira@sgm.gob.mx

 

 

 

A soil geochemical survey of the conterminous United States and Mexico was initiated in 2007. Sampling at 4857 sites in the conterminous U.S. was completed in 2010 (1 site per 1,600 square kilometres); sampling of ~1,300 sites in Mexico was completed in 2012. The following samples were collected at each site: (1) soil from a depth of 0-5 cm; (2) a composite of the soil A horizon; and (3) a sample from the soil C horizon, or if the top of the C horizon was deeper than 1 metre, a sample was collected from about 80-100 cm. Each sample was air-dried at ambient temperature and sieved to <2 mm.  The <2-mm fraction of each sample was analysed for a suite of 45 major and trace elements by methods that yield the total or near-total elemental content.  The uniqueness of this project is the determination of major mineralogical components in the samples from the soil A and C horizons by a quantitative X-ray diffraction method using Rietveld refinement.  Sampling in the conterminous United States was completed in 2010, with chemical and mineralogical analyses completed in May 2013. The resulting data set provides an estimate of the abundance and spatial distribution of chemical elements and minerals in soil samples of the conterminous United States and represents a baseline for soil geochemistry and mineralogy against which future changes may be recognised and quantified.  This final report by Smith et al. (2014):  (1) describes the sampling, sample preparation, and analytical methods used; (2) gives details of the quality control protocols used to monitor the quality of chemical and mineralogical analyses over approximately six years, and (3) makes available the soil geochemical and mineralogical data in downloadable tables. 

 

  • Smith, D.B., Smith S.M., Horton, J.D., 2013.  History and evaluation of national-scale geochemical data sets for the United States. Geoscience Frontiers, 4(2), 167-183; https://doi.org/10.1016/j.gsf.2012.07.002.
  • Smith, D.B., Cannon, W.F., Woodruff, L.G., Solano, F., Kilburn, J.E., Fey, D.L., 2013.  Geochemical and mineralogical data for soils of the conterminous United States.  U.S. Geological Survey Data Series 801, 19 pp.;  http://pubs.usgs.gov/ds/801/.
  • Smith, D.B., Cannon W.F., Woodruff, L.G., Solano, F., Ellefsen, K.J., 2014.  Geochemical and mineralogical maps for soils of the conterminous United States.  U.S. Geological Survey Open-File Report 2014-1082, 386 pp.;  http://pubs.usgs.gov/of/2014/1082/.

Interactive website:   https://pubs.usgs.gov/sir/2017/5118/ 

 

 

The Mexican results are expected to be available in 2019.