GENETIC FEATURES OF SUPERGENE MODIFIED GOLD IN WEATHERING CRUSTS

Abstract

The phenomenon of the formation of in situ (authigenic) native gold in mine dumps, alluvial placers, and oxidation zones of auriferous ore deposits was discovered in the first half of the 20th century. However, this fact had a negligible impact on the theory of ore formation or the practice of prediction, prospecting, and assessment of gold deposits. The scale of authigenic gold mineralization in nature remains unclear and debatable thus far. The role of rearrangement and secondary concentration of gold is exaggerated unreasonably. However, other researchers believe that the secondary gold is a widespread mineral that dominates in some weathering crusts and placers. The genetic classification of gold in such deposits also remains a controversial issue. According to modern concepts, the oxidation zone of ore deposits contains three types of gold particles: (1) primary particles with all features of native mineralization, (2) residual particles subjected to intense dissolution and purification (leaching of admixtures), and (3) “supergene” (newly formed) particles related to the chemogenic redeposition of the preliminarily dissolved primary gold. Estimation of proportions between genetic types of gold particles depends on the individual experience and attitude of researchers.