New data on the age of gold mineralization of the Lugokan ore cluster (Eastern Transbaikalia)

The Lugokan ore cluster is located in the southeastern part of Transbaikalia within the Aga–Borzya structural–formational zone of the Mongol–Okhotsk orogenic belt. The 40Ar/39Ar dating of K-bearing minerals of syngenetic to ore parageneses has been carried out applying stepwise heating technique: it has been demonstrated that the earliest gold-ore mineral associations are Au–pyrite–arsenopyrite (163 ±1.9 Ma) and Au–chalcopyrite (160 ±2 Ma). The later parageneses encompass the Au–polymetallic (156.3 ± 1.8 Ma) and Au–Bi (155.9 ± 4.5 Ma) one. By their ages and position in the general scheme of the Late Jurassic magmatism of Eastern Transbaikalia, the Lugokan’s ore cluster gold-bearing mineral associations corresponds to the time of intrusion of the Shakhtama pluton (161 Ma) and the Porphyry Complex (159–155 Ma).