Инд. авторы:	Murzin V., Chudnenko K., Palyanova G., Varlamov D.
Заглавие:	Formation of Au-Bearing Antigorite Serpentinites and Magnetite Ores at the Massif of Ophiolite Ultramafic Rocks: Thermodynamic Modeling
Библ. ссылка:	Murzin V., Chudnenko K., Palyanova G., Varlamov D. Formation of Au-Bearing Antigorite Serpentinites and Magnetite Ores at the Massif of Ophiolite Ultramafic Rocks: Thermodynamic Modeling // MINERALS. - 2019. - Vol.9. - Iss. 12. - Art.758.
Идентиф-ры:	DOI: 10.3390/min9120758; РИНЦ: 42933634; РИНЦ: 43223223; WoS: 000506636900042;
Реферат:	eng: We constructed thermodynamic models of the formation of two types of gold-ore mineralization at the Kagan ultramafic massif in the Southern Urals (Russia). The first type of gold-mineralization is widely spread at the massif in the tectonic zones of schistose serpentinites containing typically <= 0.1 ppm Au. The second type of gold-ore mineralization is represented by veined massive, streaky and impregnated magnetite ores in contact with serpentinites. It contains to 5 vol.% sulfides and 0.2-1.2 ppm Au. Our thermodynamic calculations explain the formation of two types of gold-ore mineralization in the bedrocks of ultramafic massifs. Metamorphic water, which is the result of the dehydration of early serpentinites (middle Riphean) during high-temperature regional metamorphism (700 degrees C, 10 kbar) (late Precambrian), is considered as the source of ore-bearing fluid in the models. The metasomatic interaction of metamorphic fluid with serpentinites is responsible for the gold-poor mineralization of the 1st type at T = 450-250 degrees C and P = 2.5-0.5 kbar. The hydrothermal gold-rich mineralization of the 2nd type was formed during mixing of metamorphic and meteoric fluids at T = 500-400 degrees C and P = 2-3 kbar and discharge of mixed fluid in the open space of cracks in serpentinites. The model calculations showed that the dominant forms of gold transport in fluids with pH = 3-5 are AuCl2- complexes (>= 450 degrees C) and, as the temperature decreases, AuHS0, or AuOH0. Mineral associations obtained in model calculations are in general similar to the observed natural types of gold mineralization.
Ключевые слова:	ORIGIN; MINERALS; TEMPERATURES; GOLD; O-H; SOLID-SOLUTIONS; TRANSPORT-PROPERTIES; HIGH-PRESSURES; SOLUBILITIES; thermodynamic modeling; native gold; gold mineralization; magnetite veins; antigorite serpentinites; Southern Urals; Kagan ultramafic massif; fluid regime; FLUID;
Издано:	2019
Физ. хар-ка:	758