a geological map showing the relative likelihood outlook for finding areas of new mineral deposits in individual regions of the territory being mapped.
Prognostic maps are usually compiled on a scale of 1:200,000 to 1:10,000, on the basis of metallogenic maps. They show areas with known deposits, areas in which the prospect of discovering new mineral deposits is promising, and areas that are not promising. Based on how favorable the chances are for discovering minerals, promising areas are usually classified as most promising, promising, and somewhat promising. By analogy to areas with established mineral deposits, promising areas are established by mapping those geological factors that control the disclosed deposits; included are factors of stratigraphy, lithology, tectonics, magmatism, and metamorphism, either singly or in combination. The geological factors that make it possible to forecast the distribution of mineral deposits are evaluated either visually or mathematically, by factor analysis. In the latter case, the significance of each geological factor for the forecast is evaluated in points, and the total makes it possible to determine which areas are most favorable for discovering new deposits. When prognostic maps are compiled, areas in which to search for new mineral deposits are noted that are both on the surface of the earth and that lie deep within the earth without emerging on the surface.
Prognostic maps make it possible to draw up general and quantitative prognoses. A general prognosis indicates only areas in which to search for new deposits. A quantitative prognosis assesses the possible or geological reserves of minerals in mineral deposits on territories that appear promising.
REFERENCEOsnovnye printsipy sostavleniia, soderzhaniia i uslovnye oboznacheniia metallogenicheskikh i prognoznykh kart rudnykh raionov. Moscow, 1964.
V. I. SMIRNOV