FORMS OF GOLD IN SECONDARY DISPERSION HALOS AND TRAINS IN TOPOGRAPHICALLY AND CLIMATICALLY DIFFERENT ZONES

Abstract

One important aspect in studying how secondary dispersion halos and trains develop is to investigate the forms in which various chemical elements occur in them. We discuss the results of our study of the forms of gold in slope wash and alluvium in certain areas of Siberia and Soviet Central Asia. For this purpose, we used the method of phase analysis based on sccessive extraction and analysis of readily mobile forms of gold - the water-soluble form, the mobile form bound to individual organic complexes and the sorbed form combined with iron hydroxides. We also recovered gold from the insoluble postleaching mineral residue. Our data indicate that gold migration and redeposition in the arid zone are much less pronounced than under the humid conditions of Siberia. In the latter case, there is more intensive solution of gold from ore bodies and host rocks, which, in turn, may lead to its significant enrichment of genetically different unconsolidated deposits. The formation of supergene gold under those conditions apparently is not such a rare phenomenon as has been supposed.