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TitleOre facies, alteration zoning and physico-chemical conditions of formation of the Bavanat (Jian) Besshi-type Cu-Zn-Ag volcanogenic massive sulfide deposit, Fars Province
AuthorMousivand, F; Rastad, E; Emami, M H; Peter, J M; Solomon, M
SourceGeosciences Scientific Quarterly Journal vol. 25, no. 99, 2016 p. 61-74
LinksOnline - En ligne
Year2016
Alt SeriesEarth Sciences Sector, Contribution Series 20140441
PublisherMinistry of Industry and Mines, Geological Survey of Iran
Documentserial
Lang.Persian
Mediapaper; on-line; digital
File formatpdf
AreaBavanat; Iran
Subjectsmineralogy; geochemistry; economic geology; volcanogenic deposits; sulphide deposits; sulphides; mineralization; mineral deposits; copper; zinc; igneous rocks; volcanic rocks; Sargaz deposit; Mesozoic; Jurassic; Triassic
Illustrationslocation maps; photographs; stratigraphic columns; diagrams; photomicrographs; histograms; plots; ternary diagrams
ProgramVolcanogenic Massive Sulfide Ore Systems, Targeted Geoscience Initiative (TGI-4)
AbstractThe Bavanat (Jian) pelitic-mafic- / Besshi-type Cu-Zn-Ag volcanogenic massive sulfide deposit locates in the Bavanat area, South Sanandaj-Sirjan zone. Mineralization occurs as two stratigraphic ore horizons discontinuously within the Surian metamorphosed volcano-sedimentary complex through more than 35 km in the area. Stratigraphicaly, from footwall toward hangingwall, four ore facieses were distinguished within the Bavanat (Jian) orebodies including: 1) vein-veinlets or stringer, 2) vent complex, 3) bedded-banded, and 4) hydrothermal-exhalative sediments. The ores have various primary and secondary textures and structures, although most of the primary ones were obscured during metamorphism and deformation. The relict primary textures include massive, semi-massive, banded, brecciated, disseminated and vein-veinlet ores. In the stringer and specially in the vent complex facies, chalcopyrite replaced pyrite indicating influx of a hot copper-rich fluid into the pyrite-rich massive ores during zone refining process. Also, a metal and mineralogical zonation is obsereved in the Bavanat deposit. The major wall rock alterations in the Bavanat deposit from center to margins are silicic, quartz-chlorite, chloritic, chlorite-carbonate and chlorite-sericite, which show zonal pattern. Based on electron microprobe studies, chlorite is of iron-rich type. The abundant pyrrhotite in the Bavanat deposit might be due to low oxygen and sulfur fogacity, and occurrence of abundant chlinochlor in the alteration zones may indicate low pH (between 4.3 and 5.3) conditions for the ore-forming fluids. The high amounts of Cu and Zn, and low amounts of Pb, along with fluid inclusion studies results indicate high temprature (300-350oC) for the ore fluids. Based on this study, the ore fluids responsibe for formation of the Bavanat deposit were hot, reduced and acidic, which entered into a confined marine basins, followed by ore deposition.
GEOSCAN ID295833