Mineralogy of Arsenian Pyrites and Arsenopyrites of Carlin-Type Gold Deposits in Yunnan-Guizhou-Guangxi “Golden Triangle” Area, oft-com:office:smarttags" />Southwestern China oft-com:office:office" />
Petrographic observations and electron-probe micro-analysis (EPMA) of sulfides from different subclasses of typical Carlin-type gold deposits in Yunnan-Guizhou-Guangxi “golden triangle” areas show that both arsenian pyrites and arsenopyrites are major gold-bearing minerals. Gold-bearing pyrites are dominated by zoned arsenic pyrites and fine-grained euhedral arsenian pyrites. The major modes of occurrence for gold are “invisible” nanometer-size sub-microscopic inclusion gold grains, with minor ones being “invisible” lattice gold and “visible” micrometer-size microscopic native gold. The gold-bearing minerals and the gold modes of occurrence have no essential difference in different subclasses of Carlin-type gold deposits in Yunnan-Guizhou-Guangxi “golden triangle” areas, suggesting that they had the same ore-forming process and setting.