Economic Geology
S. Maleki; A. A. Calagari; K. Siahcheshm; S. Alirezaei
Abstract
Khak Sorkh iron deposit located about 42 km northwest of Nadushan town in Yazd Province. Host rock include upper Triassic-Jurassic limestone which are intruded by Oligo-Miocene granitoid bodies. Mineralization is dominated by magnetite, and serpentine is the main waste mineral. Skarn mineral assemblages ...
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Khak Sorkh iron deposit located about 42 km northwest of Nadushan town in Yazd Province. Host rock include upper Triassic-Jurassic limestone which are intruded by Oligo-Miocene granitoid bodies. Mineralization is dominated by magnetite, and serpentine is the main waste mineral. Skarn mineral assemblages include clinopyroxene, garnet, tremolite phlogopite and epidote. The characteristics of mineralization are: magnetite mineralization in two generations, presence of serpentine as the main waste mineral, hornfelsed greywacke units which come between intrusive bodies and skarned limestone units, absence of obvious zoning in endoskarn and exoskarn parts, presence of Ni-Co-As sulfides, high amount of Zn, As, Co and Mn in magnetite geochemical results and the increasing Fe along with decreasing Mg contents in magnetite at both deposit and crystal scales from primary to secondary types. Minor elements contents of geochemical results have been used for distinguishing of different mineral deposits (e.g, Dare et al., 2012; Dupuis and Beaudoin, 2011; Nadoll et al., 2012) and they are in good accordance to hydrothermal and skarn type deposits like: low contents of Cr (less than 10 ppm), high contents of Mg (2.2 to 7.5 ppm), low TiO2 (from 0.01 to 0.3 ppm), low amounts of incompatible elements including Ag (
Z. Mohammadzadeh; M. Ghaderi; S. Alirezaei; J. Hassanzadeh
Abstract
The Raziabad porphyry copper deposit is located 30 km north of the city of Jiroft, in southeastern part of the Urumieh-Dokhtar magmatic arc, southeastern Iran. Several intrusive bodies including diorite, gabbro, granodiorite and quartz-diorite associated with groups of dikes with similar composition ...
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The Raziabad porphyry copper deposit is located 30 km north of the city of Jiroft, in southeastern part of the Urumieh-Dokhtar magmatic arc, southeastern Iran. Several intrusive bodies including diorite, gabbro, granodiorite and quartz-diorite associated with groups of dikes with similar composition as well as dissimilar composition with the intrusions, intruded into the Raziabad porphyry system. The porphyry copper mineralization is associated with the granodiorite which intruded into dioritic, gabbroic and volcano-pyroclastic rocks. The magmatic activities continued after mineralization and lead to the emplacement of the quartz-diorite as well as intrusion of two groups of micro-granitic and andesi-basaltic dikes cutting the ore body, causing geometric complexity of the ore body. The alteration zones include potassic and magnetite-rich silicification zones, relatively restricted calcic zone, and propylitic zone. Phyllic alteration with restricted expansion and weak intensity overprinted on potassic alteration. The hypogene mineralization has occurred as disseminated, stockwork and veinlet styles closely associated with the potassic alteration zone. The main ore minerals are chalcopyrite+ magnetite+ pyrite with minor molybdenite, pyrrhotite, galena and sphalerite. The oxidation and enriched supergene zones are variable and restricted to the shallow levels. Hydrothermal activity in Raziabad deposit is classified into four stages on the basis of hydrothermal mineral assemblage and veinlet relation. The stages include: 1) calcium silicate-magnetite-quartz stage; 2) potassium silicate-sulfide-quartz-magnetite; 3) sericite-quartz-pyrite stage; 4) chlorite-epidote-calcite-pyrite±actinolite.
F Padyar; M Rahgoshay; S Alirezaei; M Pourmoafi; A Tarantola; O Vanderhaeghe; M Caumon
Abstract
The Latala base and precious metals deposit is hosted by quartz veins, associated with a porphyry pluton intruded into a Cenozoic volcanic sequence. Euhedral quartz with sulfide mineralization such as pyrite, chalcopyrite, galena and sphalerite, with minor sulfosalts occurs in these veins as open space ...
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The Latala base and precious metals deposit is hosted by quartz veins, associated with a porphyry pluton intruded into a Cenozoic volcanic sequence. Euhedral quartz with sulfide mineralization such as pyrite, chalcopyrite, galena and sphalerite, with minor sulfosalts occurs in these veins as open space fillings and minor replacement bodies. Progressive growth of quartz crystals is evidenced by their texture revealed by cathodoluminescence imaging. The analysis of fluid inclusions indicate a decreasing homogenization temperature from 350°C in the core to 135°C along the edge of the quartz crystals with overgrowths. The presence of CO2 vapor suggested by the thermometric analysis is confirmed by Raman spectrometry. The solid phases in fluid inclusions identified as phyllosilicates, presumably muscovite and illite, chlorite, quartz and carbonate-mineral such as (Natrocarbonate, Dawsonite) by petrography and Raman spectrometry. Solid phase of halite were identified in two fluid inclusions. The homogenization temperature and salinity varies between 131 to 380 °C and 0.17 to 7.7 wt.% NaCl eq respectively. The properties of fluid inclusions corresponds to a magmatic hydrothermal fluid circulating from depth to shallower environments. The sulfur isotopic composition for galena, sphalerite, chalcopyrite and pyrite varies between -9.8 and -1‰, which correspond to values of magmatic sulfur. The δ34S values from +1.8 to -9.2‰ are in the range of hydrothermal fluids. Fluid inclusions features show a magmatic hydrothermal source which transported magmatic fluid and vapor from the depth through fractures to shallow environment. It suggests that magmatic water mixing with meteoric water was responsible for transportation of metals in Latala. Epithermal mineral precipitation during boiling, mixing and water-rock interaction formed hydrothermal quartz and sulfide mineralization. The available evidence suggests that the hydrothermal fluids changed from magmatic to epithermal in the region.
