The first finding of native bismuth, waylandite and beyerite in alluvial gold placer deposits of Angara region, Yenisei ridge
S.V. Pribavkin, P.S. Kozlov, S.V. Mazur, I.A. Gottman, D.A. Zamyatin, S.G. Sustavov
The pebbles from alluvial gold placer deposits of the upper reaches of the Tatarka river in Angara region, Yenisei Ridge, are composed of bismuth minerals: crystal aggregates of native bismuth and pseudomorphic secondary oxides, carbonates, and phosphates. Secondary minerals include bismite, bismuthite, beyerite, waylandite, waylandite-(Ca), and crandallite-(Bi). The pseudomorphs mainly consist of bismite and bismuthite, which form reticulate and concentric cryptocrystalline aggregates, whereas beyerite, crandallite-(Bi), and waylandite-(Ca) form veins. Waylandite occurs in dissolution cavities. The presence of relatively fresh native bismuth pebbles and products of their oxidation in alluvial placers is considered to be a searching indicator of proximal gold and bismuth-bearing deposit.
Figures 6. Tables 4. References 20.
Key words: native bismuth, waylandite, beyerite, bismite, bismuthite, Yenisei Ridge, Tatarka, placer gold.
МINERALOGY № 2 2017