MORE than 30 gossan-type gold deposits have beed discovered in the Middle-Lower Yangtze River Area.The profile of gold-bearing gossan can be divided into four subzones from upper to lower: (i) gold-deficient or gold...MORE than 30 gossan-type gold deposits have beed discovered in the Middle-Lower Yangtze River Area.The profile of gold-bearing gossan can be divided into four subzones from upper to lower: (i) gold-deficient or gold-leached gossan (Au contents (0.1-0.8)×10<sup>-6</sup>) transitonal subzone; (ii) secondary goldconcentration subzone (Au(4-20)×10<sup>-6</sup>); (iii) oxide and sulfide transitional subzone (Au(0.5-1.5)× 10<sup>-6</sup>); (iV) Primary sulfide ore (Au(0.5-1) × 10<sup>-6</sup>). Au Concentration in the subzone (ii) is 2-20 times higher than that in subzone (iV). Obviously migration and secondary concentration of Au hadhappened in the process of oxidation of primary sulfides. Some geologists indicated that there would be four modes of gold-migration and concentration:(1) gravity separation (mechanism); (2) organic complex or adsorption; (3) colloidal展开更多
文摘MORE than 30 gossan-type gold deposits have beed discovered in the Middle-Lower Yangtze River Area.The profile of gold-bearing gossan can be divided into four subzones from upper to lower: (i) gold-deficient or gold-leached gossan (Au contents (0.1-0.8)×10<sup>-6</sup>) transitonal subzone; (ii) secondary goldconcentration subzone (Au(4-20)×10<sup>-6</sup>); (iii) oxide and sulfide transitional subzone (Au(0.5-1.5)× 10<sup>-6</sup>); (iV) Primary sulfide ore (Au(0.5-1) × 10<sup>-6</sup>). Au Concentration in the subzone (ii) is 2-20 times higher than that in subzone (iV). Obviously migration and secondary concentration of Au hadhappened in the process of oxidation of primary sulfides. Some geologists indicated that there would be four modes of gold-migration and concentration:(1) gravity separation (mechanism); (2) organic complex or adsorption; (3) colloidal