Paragenetic relationship between Biryuzakan and Karamazar deposits

Biryuzakan is one of the well-known high-grade turquoise deposits in the area of the CIS countries. The deposit lies almost in the center of the largest ore-bearing region of Karamazar, Northern Tajikistan, producing Pb, Zn, Cu, Bi, U, Ag, Au et al. at more than 28 industrial facilities. The Biryuzakan deposit was never considered as a promising ore bearer despite the turquoise exploration and studies carried out for nearly 20 years by SoyuzKvartSamotsvety Association. The deposit occurs in the hanging wall of the large Biryuza fault, and is composed of the Akcha medium-acid volcanic rock suite (С2). The volcanic rocks are complicated by small (thickness of a few centimeters, length of a few meters) but numerous quartz veins of a few generations, adjoined by turquoise mineralization. Alongside with turquoise in the composition of the veins, the authors detect holomorphic aggregates of gibbsite containing (wt%) CuO to 2.7, MnO to 0.4, SO3 to 1.2 and F to 4.5, and inclusions of small magnetite grains containing to 3.5 Cu and 3.6 MnO. In the composition of quartz veins with turquoise at the Biryuzakan deposit, a group of ore minerals is identified (magnetite, rutile, pyrite, chalcopyrite, green copper, faustite, kleemanite, chalcosiderite, argentojarosite, ganningite, vanadinite), containing significant quantities of Pb, Zn, Ag, Cu, Fe, Co, V, As and rare earths. Biryuzakan chalcopyrite forms two generations. Biryuzakan localization of these minerals is a characteristic feature of ore deposits at Karamazar. This fact is a background for stating a paragenetic relationship between the Biryuzakan deposit and other ore deposits in the region. In this connection, formation of Biryuzakan can be connected with the orogeny in the Karamazar region as a late link in the endogenous cycle, which provides a new idea of turquoise genesis and prospects of the studied gem-bearing mineralization.