Economic Geology
Seyed Mehran Heidari; Sara Safavy; Afshin Akbarpour; Azra Hassanlou; Bahram Mohaghegh
Abstract
Saveh-Razan copper (± gold) area, with WNW direction in the northwest of Urmia-Dokhtar magmatic belt, with the highest reaction to right-sided shear zones and structural trend change during the Oligomyocene, leads to the placement of semi-deep Oligomyocene diorite massifs in shallow rock depths. ...
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Saveh-Razan copper (± gold) area, with WNW direction in the northwest of Urmia-Dokhtar magmatic belt, with the highest reaction to right-sided shear zones and structural trend change during the Oligomyocene, leads to the placement of semi-deep Oligomyocene diorite massifs in shallow rock depths. It is an Eocene volcano. By creating different types of mass-related hydrothermal alteration (propylitic, intermediate-advanced argillaceous, and phyllite) along the fractures, the system concentrates the mineralizations in quartz-sulfide veins, hydrothermal incisions, and concentrated sulfide-bearing filaments. Common features of metallurgy in this area are fluid homogenization temperature between 250 to 350 ° C and salinity range of 6-28% by weight of salt, containing CO2 gas and liquid phase of liquid and the presence of sulfides such as pyrite, chalcopyrite, burnite, chalcocite and sulfosalts in related reserves. There is also more gold than silver. Therefore, these features are most similar to the mass-related intermediate-type epitermal deposits that form in calcoalkalkene magmatic arcs.
Economic Geology
seyran yousefi; masoud alipourasl
Abstract
The Zarandieh district is situated approximately 42 km northeast Saveh (Markazi province) and in the northwestern part of the Urumieh-Dokhtar magmatic belt. In this area, mineralization is hosted by Eocene andesitic lava and Oligo-Miocene diorite and gabbroic rocks. According to the geochemical evidence, ...
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The Zarandieh district is situated approximately 42 km northeast Saveh (Markazi province) and in the northwestern part of the Urumieh-Dokhtar magmatic belt. In this area, mineralization is hosted by Eocene andesitic lava and Oligo-Miocene diorite and gabbroic rocks. According to the geochemical evidence, parental magma of igneous rocks is calc-alkaline, metaluminous and related to continental margin volcanic arcs. Mineralization has been observed as veins, veinlets and brecciated forms in diorite and gabbroic rocks. The main ore mineral is chalcopyrite and associated with pyrite, bornite, oligist, chalcocite, covellite, neotosit, native copper, malachite, azurite, chrysocolla, goethite and limonite. Cu grade in the ore samples are varied from 0.04 to 1.7 % (0.40 % in average). Statistical analyses of geochemical data from mineralized samples by Pearson method displayed that Cu has maximum correlation with Ag, As, Zn, Cd and Pb, respectively. Microthermometry studies of fluid inclusions show that the average homogenization temperature is 195° C and the average salinity of 23 wt% NaCl. The Zarandieh Copper mineralization is closely related to hydrothermal vein copper deposit types.
K Orang; M Mohajjel; G.R Tajbakhsh
Abstract
The kinematic analysis of the Koushk-e-Nosrat Fault (striking WNW-ESE) at north Saveh city indicates that since a time after early Miocene it has been inverted from dextral strike-slip (and reverse-dextral-oblique slip) to reverse-sinistral (and sinistral strike-slip( displacement. The Kinematic evidences ...
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The kinematic analysis of the Koushk-e-Nosrat Fault (striking WNW-ESE) at north Saveh city indicates that since a time after early Miocene it has been inverted from dextral strike-slip (and reverse-dextral-oblique slip) to reverse-sinistral (and sinistral strike-slip( displacement. The Kinematic evidences of right-lateral strike-slip displacement are: 1) Generation of the Koushk-e-Nosrat pull-apart basin along the bended segment of the fault in north Saveh city where a thin sequence of the Qom Formation (late- Oligocene to early Miocene) has been deposited in this narrow basin. 2) Shear bands and other kinematic indicators of right-lateral strike-slip and reverse-dextral-oblique slip displacements exist in the fault zone. 3) Synthetic right-lateral and antithetic left-lateral strike-slip faults are observed in wall damage zones around the main fault zone. The evidences of left-lateral strike-slip displacements after slip sense inversion are: sinistral- reverse faults, pure reverse faults, sinistral strike-slip faults and folds are generated in the Koushk-e-Nosrat Fault zone. The younger left-lateral reverse kinematic of the Koushk-e-Nosrat Fault is another significant evidence for the main role of the left-lateral reverse faults in deformation of the Qom-Saveh district in NW part of the Central Iran Block that has been tested before by structural and morphological kinematics of other major faults in the area like the Ipak (south Boin-zahrah) and Alborz (north Qom) Faults and seismological evidence of earthquake in the Boin-zahra areas.
H. Ghasemi; A. Ramazani; A. Khanalizadeh
Abstract
Silijerd intrusion with an age of Late Eocene – Oligocene (39.23.2 Ma) is located in Uromeyeh-Dokhtar magmatic arc, central Iran structural zone, northwest Saveh. This intrusion is composed of a continuous compositional range including: diorite/gabbro, ...
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Silijerd intrusion with an age of Late Eocene – Oligocene (39.23.2 Ma) is located in Uromeyeh-Dokhtar magmatic arc, central Iran structural zone, northwest Saveh. This intrusion is composed of a continuous compositional range including: diorite/gabbro, granodiorite, syeno-monzogranite and alkali granite intruded into the Eocene volcanic and pyroclastic rocks.
Variation diagrams showing trends of major and trace elements indicate a continuous compositional range and a comagmatic origin for these rocks. Trends of compatible- incompatible elements indicate the important role of fractional crystallization in the genesis of these rocks. All samples are metaluminous with medium-high K with calc-alkaline nature. High values of Rb, Sr, K, U, Th, Zr and Ba and high ratios of K2O/Rb and FeO/MgO indicate the similarity of the rocks of this intrusion with the rocks of continental margin magmatic arc intrusions. Depletion in Nb,P,Ta and Ti and enrichment in K,Sr,Rb,Cs and Ba are obvious in the spider diagrams of these samples. The enrichment in LILE and depletion in HFSE reveal the I-type metaluminous magmatism of volcanic arcs (VGA). Whole rock 87Sr/86Sr ratios of this intrusion range from 0.704759 to 0.705166 and it can be correlated with the values of these ratios in the mantle and lower crust sources and low contamination of their magmas with upper crust.
Existence of K-feldspar megacrysts and mafic microgranitoid inclusions in this intrusion, high abundances of La and Ce , V enrichement in mafic terms and low whole rock 87Sr/86Sr ratios of this body, suggested a partial melting of mantle wedge, subducted oceanic crust (metabasaltic sources) or lower continental crust (metatonalitic sources) origins for it. The discrimination tectonic setting diagrams also indicate an I-type continental volcanic arc magmatism for this intrusion.
