QE472 : Mineralogy, geochemistry and genesis of Rameshk Copper deposits, South-East of Kerman
Thesis > Central Library of Shahrood University > Geosciences > MSc > 2019
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Abstarct: Copper mineralization in the Rameshk area, occured in the South East of Kerman province, in the Cretaceous Durkan mextamorphic complex, Makran structural zone, and includes Tankashku 1 and 2, sarsu, Mimandar and Kermahoo deposits. The Durkan mextamorphosed volcano-sedimentary sequence mainly consists of the following units from bottom to top: Unit 1: pillow basaltic lava, Unit 2: includes mextabasalt, basaltic andesite with calc schist, chlorite schist, mextapelite and radiolarite (ore-bearing host unit) with subunits of laminar and thick-bedded limestones composed of four subunits. Unit 3: includes mextamorphosed green tuffs, Unit 4: includes sandy limestone. Degree of the regional mextamorphism in the Durkan complex is the green schist facies. In general, two ore-bearing horizons are detectable in the region: first ore horizon (OH-1): within the Kvs-1 subunit occurred in the second unit of the host sequence and comprises Tankashku 2 deposit. Second ore horizon (OH-2): within the Kvs-2 subunit occured in the second unit of the host sequence and includes the Tankashku 1, sarsu, Mimendar, and Kermahoo deposits. Ore textures and structures are dominated by massive, brecciated, vein-veinlets and disseminated. baxsed on mineralogical, textural and structural studies and relationship between ore and the host rocks, three ore facies can be identified in the Remeshk copper ore deposits, from bottom to top: 1) vein-vein facies or stringer zone; this facies as a network of irregular ore vein-veinlets cross cuts through footwal host rocks, 2) vent-complex facies, this facies is located between the massive and stringer facies, which is observed as brecciated ore above the vein-vein facie, and 3) Massive ore facies as tabular orebodies located above the vent complex and stringer facieses. Mineralogically, these deposits are composed of primary minerals of pyrite, chalcopyrite, sphalerite, magnetite, hematite (specularite) and titanite, and secondary minerals of malachite, cavollite and iron oxide- hydroxides, and gaungue minerals mainly involve quartz, calcite, chlorite, epidote and barite. The most important alterations include chloritic, silicic-carbonatic, epidotic and argillic. Geochemical studies on the host rocks reveal th tholeiitic nature of the volcanic rocks in the area. Copper mineralization in the Rameshk region ocurred in extensional basins near the volcanic arcs associated with subduction in a continental margin. According to geochemical studies, the ores are rich in copper and iron, and the amount of zinc and lead is lower. In this deposit, iron has the highest amount in the vent complex, about 10 wt%. Also, the highest amount of copper belongs to the stringer facies, and is 5.8 wt%. The highest amount of zinc and lead belong to the lower parts of the massive ore, about 1450 and 4500 ppm, respectively. According to the microthermometery of fluid inclusions on quartz from the Sarsu deposit, the liquid-vapor (L+V) and liquid-rich single-phase (L) inclusions are dominate and show a salinity range of 1 to 15 wt.% eq. NaCl, with the highest frequency of 4-7 wt.%. Homogenization temperature is between 110 and 220 °C, with the highest frequency from 160 to 180 °C. Considering the basic features of ore mineralization in the Rameshk district, including tectonic setting, host mineralization sequence, ore-bearing facies, geometry of orebodies, mineralogy, ore textures and structures, mextal content, mextal and alteration zonation, copper mineralization in the Rameshk region can be classified as Besshi (siliciclastic mafic or pelitic mafic.-type volcanogenic massive sulfide (VMS) deposits.
Keywords:
#Durkan Complex #copper #VMS #Besshi #Cretaceous #Rameshk Link
Keeping place: Central Library of Shahrood University
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Keeping place: Central Library of Shahrood University
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