Physico-chemical conditions of vent fauna fossilization in the VMS deposits of the Urals and Pontides: fluid inclusion data
N.N. Ankusheva, V.V. Maslennikov, N.P. Safina
UDК 553.43: 553.21
Fluid inclusions in quartz, barite and calcite from fossilized fauna of hydrothermal massive and clastic ores from the deposits of the Urals (Valentorka, Saf’yanovka, Yubileynoe, Molodezh-noe, Shemur) and Pontides (Killik, Kyzylkaya) are studied with microthermometry, Raman spec-troscopy and gas chromatography. Quartz from hydrothermal fauna was formed from NaCl and NaCl-KCl fuids with salinity up to 5–10 wt. % NaCl-equiv. and homogenization temperatures (Тhom) varying from 100 to 180 °C. Calcite from fauna was formed from the fuids with higher Тhom (200–250 °C) and lower salinity (3.5–7 wt. % NaCl-equiv.). Fluid inclusions in barite from fauna in clastic ores are characterized by variable salinity from 0.7–2 wt. % to 6–7 wt. % NaCl-equiv. (max 11 wt. %) and low to moderate Тhom (100–200 °C). Quartz of fauna from banded ores was formed from medium-temperature (Тhom 120–180 °C) NaCl-KCl fuids with salinity of 5–9 wt. % NaCl-equiv. According to gas chromatography and Raman spectroscopy, the fuids contain variable amounts of CO2, CH4 and N2.
Figures 8. Tables 3. References 29.
Key words: Urals, Pontides, VMS deposits, fauna, quartz, calcite, barite, volatiles, thermobaro-geochemistry, Raman spectroscopy.
МINERALOGY № 1 2016