Frakcyjne zdjęcie aluwialne - nowa metoda prospekcji geochemicznej

FRACTIONAL ALLUVIAL IMAGE - A NEW METHOD OF GEOCHEMICAL PROSPECTING Summary Fractional alluvial image, involving distinquishment of 6 grain-size classes, was applied in prospecting stannum ores in the range of metamorphic slates of northern cover of the Karkonosze granite. The method makes it possible to distinquish secondary aureoles of dispersion around mineralized zones characterized by the occurrence of cassiterite grains; the grains are very small in size, some are over 0.1 mm in diameter. Recognition of enrichment in stannum grains of any fraction enables evaluation of the size of cassiterite grains in primary ore. Fractional image may also be of same value in searching for alluvial concentrations of economic importance.