QE397 : Mineralogy, geochemistry and genesis of the Nohkuhi copper deposit, Northwest of Kerman
Thesis > Central Library of Shahrood University > Geosciences > MSc > 2018
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Abstarct: The Nohkuhi copper deposit located at 40 Km Northwest of Kerman, occurred in the Central Iran structural zone (Posht-e- Badam block), within Late Precambrian-Early Cambrian volcano-sedimentary sequence. The host rocks consist of dominantly black shale and dacitic lava of Rizu Series. Host sequence in the Nohkuhi deposit involves three units, from bottom to top: Unit1: sandstone, Fossiliferous limestone, Green Tuff and Fe- Mn Exhalite, Unit2: Light, well bedded sandstone, Unit3: volcano-sedimentary involves Black shale, Dacite, Red shale and Prismatic dacite, Unit4: consist of limestone, dolomite, sandstone. baxsed on textural, structural and mineralogical aspects and relationship between the ores and host rocks, the Nohkuhi copper deposit involves four different ore facies as follows:1) vein-veinlets or stringer facies, includes veins mineralization scissors of host rocks shaly and dacitic lava(Occasionally bedded ore facies), 2) vent complex facies, This facies involves pieces bedded ore facies In the context of sulfidi and carbonatic minerals , 3) Bedded ore facies, This facies Includes laxyered and banded sulfide is that Caused precipitation concurrent sulfide minerals with Particles shaly host rock in subseafloor, 4) banded iron and manganese-rich exhalative sedimentary unit. Minerlogically, the Nohkuhi deposit contains primary pyrite, chalcopyrite, sphalerite, hematite and pyrolusite and secondary malachite, covelline, digenite and Fe-oxide and hydroxide and Gangue minerals consist of barite, calcite and quartz. Wallrock alterations are dominated by chloritic and carbonatic-sericitic- silicic. Generaly, the study area consist of three copper- and two iron-manganese-rich horizons which include: OH1: within unit1 of the host volcano-sedimentary sequence as banded iron and manganese-rich exhalative sedimentary rocks, OH2: similar to the first one horizon, OH3: within unit3 of the host sequence, from bottom to top contains stringer, vent complex, and bedded ore facies, OH4: similar to the third horizon and contains stringer, vent complex, and bedded ore facies, OH5: this horizon only occurred as stringer ore facies. In according to geochemical study, tectonic setting of the Nohkuhi deposits was an continental margin arc. In according to geochemy study, this deposit is cu-rich and Zn- pb is very low. The amount of copper in stringer zone (10.87%) plus bedded ore facies(181ppm) deposit, but occurred in copper mineralization as Cpy in stringer zone. baxsed on microthermometry of fluid inclusions, dominant fluid inclusion types are of primary two-phase liquid/vapour inclusions with relatively moderate to low salinity (9 to 11 wt% NaCl eq.), and homogenisation temperatures about 180 to 250°C. In according to proving amount δ٣٤S sulfides range from 8.5 to 18.1 ‰, suggestion inorganic sulfate significant source sulfur in Nohkuhi deposit. The most important characteristics of mineralization at the Nohkuhi deposit such as tectonic setting, host rocks, textural and structural and mineralogy of ores, mextal content and mextal zonation, as well as wall rock alteration, show the most similarities with the volcanogenic massive sulfide (VMS) deposits. Accordingly, Nohkuhi copper deposits could be classified as Siliciclastic felsic (Bathurst).
Keywords:
#volcano-sedimentary sequence #copper #volcanogenic massive sulfide (VMS) #Late Precambrian-Early Cambrian #Nohkuhi #Posht-e- Badam
Keeping place: Central Library of Shahrood University
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Keeping place: Central Library of Shahrood University
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