Geochemical map shows an elemental distribution in the surface of earth's crust, which gives us, for example, the concentration of toxic chemicals such as arsenic, mercury and cadmium around us and enables to evaluate what kind of influence affects our life from them.
n 1988, a global geochemical map project covering entire world was planed by International Union of Geological Science (IUGS) and call for more than the world 70 countries to join the project. In European countries, the maps covering whole country have already been completed in England, West Germany, Finland and Poland.
The geochemical map of 53 elements in Japan covering whole country including toxic elements such as As, Be, Cd, Hg, Mo and Sb is now progressing in the National Institute of Advanced Industrial Science and Technology (AIST), and the compilation is scheduled to complete in 2003.
The geochemical map of Pb in Chugoku district is shown in Figure. The concentration of Pb is high in the several places where mineral deposits are located. The concentration of K2O is high in east and middle of Chugoku District, where acidic rocks (granite and rhyolite) are distributed. And the elements of MgO, P2O5, and V are high in concentration in the west of Chugoku District, where basic rocks (andesite and basalt) are distributed. The relations between the elemental distributions, the background geology, the mineral deposits and human activities are now investigated.
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No.2 2001
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