GEOCHEMICAL EXPLORATION OF MINERAL DEPOSITS

Abstract

In order to explore the mineral deposits of any country whether exposed or concealed, the basic approach is to prepare the systematic geological map of the concerned area, followed by geochemical and geophysical surveys of the area. In modern times, the geochemical and geophysical surveys have become sophisticated, and the end users multiplied. However, in this write-up only geochemical surveys of Precambrian rocks exposed along the crustal part of Indian continent will be discussed. Geochemistry utilizes the principles of chemistry to explain the mechanisms regulating the variations of rocks, past and present of the major geological systems such as the Earth’s mantles, its crust and its atmosphere (Mason, 1966). Just as the geological map (say 1:50,000 scale) essentially depicts the disposition of the rocks of the different geological formations and, depending on the needs, various levels of structural and detailed petrological information can be incorporated in it. Similarly, a geochemical map can aim at projecting surficial chemical variation involving one or more elements. Through a more detailed and advanced study, one might be interested to enquire into the inter-relationship of a suite of rocks in a complex assemblage and their chemical compositional variability. Such an endeavour depends heavily on petrochemical evidences (Rose et al., 1979). Similarly, an environmental geochemist who is interested in studying effect of one chemical element or an association of elements on vegetation or on human life, would like to get the basic data from a geochemical map only.