Gold abundances iu granitic rocks of differeat geological periods of Southern China were estimated. A review of the quantitave data now availabe indicates that unaltered granitic rocks have a rather restricted range in gold content, rarely exceeding 4 ppb and generally range from 1.4 to 3.3 ppb.Mean gold content tends to decrease from basic to acid granitoids. This tendency suggests that gold is not concentrated in the residual silieate melt during the formation of granitic rocks. Abundance dtata for granitoids in Southern China provide no geochemical clues or guides to distinguish areas favorable or unfavorable for gold mineralization, but they are necessary to establish background values for various rock types.
Six elemental groups in the gold deposits in the study region have been distinguished:( 1 ) tungsten-antimony-gold; (2) tungsten-gold; (3) antimony-gold; (4) lead-zinosilvergold; (5) uranium-silver-gold; (6) simple gold. Discussed in the present paper are the distribution, source, mineralization, migration and concentration of gold. The resuhs show that the ore-controlling strata or source beds related to gold deposits all show high background values of gold; the gold and other associated ore-forming dements are obviously derived from the country rocks. Mineralization is related chiefly to regional metamorphism in the ore-controlling strata, or alkali-pervasing metasomatism. During metamorphism in the orecontrolling strata, gold was released into solutions, and then transported and deposited in some localities. Gold carried in hydrothermal solutions occurs mainly in the form of Na[Au(SH)2]. Native gold or electrum were precipitated from the ore solutions and concen.trated into ore deposits with the decrease of T, pH and fO2.
