Noble-metal mineralization of the Adycha-Taryn metallogenic zone: geochemistry of stable isotopes, fluid regime, and ore formation conditions

摘要

The regional geologic setting of the Adycha-Taryn metallogenic zone, one of the areas most productive for noble-metal mineralization in northeastern Russia, is discussed. The intricate metallogenic history of the zone and the prolonged geodynamic activity of its ore-hosting structures are documented. Different types of mineralization, such as hydrothermal-metamorphogenic, gold-bismuth, gold-quartz, gold-antimony, and silver-antimony, are described. New data on the isotopic compositions of oxygen in quartz, sulfur in sulfides, and oxygen and carbon in carbonates from different mineralization types are presented. The early metamorphogenic quartz beyond the ore zones has delta O-18 = +20.1 +/- 2.0 parts per thousand. At the gold-bismuth deposits, the delta O-18 values of quartz are within the narrow range of +12.5 +/- 0.4 parts per thousand. Quartz from the gold-quartz mineralization shows much wider variation in delta O-18 values, from +14.2 to +19.5 parts per thousand. A similar range (delta O-18 = +16.1 to +19.2 parts per thousand) is observed for the gold-antimony mineralization. Crzptograined quartz from the silver-antimony mineralization is enriched in light oxygen isotopes (delta O-18 = -3.2 to +4.7 parts per thousand). The following delta S-34 values (parts per thousand) have been established in sulfides of mineralization of different types: gold-bismuth -3.7 to -2.2 (Apy) and -6.7 to -6.8 (Py); gold-quartz -2.1 to +2.4 (Apy), -6.6 to +5.4 (Py), and -6.1 to +4.2 (St); gold-antimony -2.0 to +1.6 (Apy), -3.5 to +2.1 (Py), and -5.3 to +0.2 (St); and silver-antimony -2.0 to -1.9 (Apy), -2.2 +/- 0.1 (Py), and -5.7 to -5.6 (St). The delta C-13 and delta O-18 values are contrasting in the studied types of mineralization, varying respectively from -6.9 to -5.9 parts per thousand and from +2.1 to +5.7 parts per thousand (gold-bismuth), from -9.1 to -6.1 parts per thousand and from +12.4 to 18.7 parts per thousand (gold-quartz), from -12.1 to -9.5 parts per thousand and