Economic Geology
Reza Ghezelbash; A. Maghsoudi
Abstract
Varzaghan district is located in NW of Arasbaran magmatic belt (AMB) which is one of the most highly mineralized region in Iran and host to a significant number of porphyry Cu deposits such as Sungun Cu-Mo porphyry deposit. The main goal of this study is synthesizing diverse raster-based evidence layers ...
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Varzaghan district is located in NW of Arasbaran magmatic belt (AMB) which is one of the most highly mineralized region in Iran and host to a significant number of porphyry Cu deposits such as Sungun Cu-Mo porphyry deposit. The main goal of this study is synthesizing diverse raster-based evidence layers including geochemical, alteration and geological geo-data sets for mineral prospectivity modeling (MPM). For this purpose, firstly, continuous values of six favorable evidential maps as main criteria (geochemical signature of PC1 scores, values of proximity to argillic, phyllic and iron-oxide alterations, values of proximity to Oligo-Miocene intrusions and fault density) were divided into reasonable classes by applying concentration-area fractal model and then discretized layers were integrated using analytical hierarchy process (AHP) and technique for order preference by similarity to ideal solution (TOPSIS) to generate a final map of porphyry Cu potential within the central part of Varzaghan district. Finally, the success-rate curve of the AHP-TOPSIS model as a quantitative evaluation method according to the locations of known Cu occurrences was drawn. Results revealed the successful performance of AHP-TOPSIS model in portraying the prospective areas related to porphyry Cu mineralization.
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.
M Farmahini Farahani; A Khakzad; H Asadi Harooni; M.H Emami
Abstract
Kahang copper and molybdenum mine is located in Esfahan province and 10 Km far from the east of Zefreh town that is on Urumieh-Dokhtar volcanoplutonic belt. The Kahang region is an alteration and breccia zone. Generally, hydrothermal fluids have affected more than % 90 of rocks of this region. These ...
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Kahang copper and molybdenum mine is located in Esfahan province and 10 Km far from the east of Zefreh town that is on Urumieh-Dokhtar volcanoplutonic belt. The Kahang region is an alteration and breccia zone. Generally, hydrothermal fluids have affected more than % 90 of rocks of this region. These alteration are related to Copper (Cu) and Molybdenum (Mo) porphyry deposits. Most of the rocks are acidic, semi acidic and sub volcanic. Several kinds of alteration are observable in kahang as propylitic, argilic, silisification and phyllic. The basic oxides were highly decreased in dacite and rhyodacites of exploration area. This is an evidence of argilic alteration effect on the rock units considering that main deposit is not affected by erosion, placed in depth and potassic alteration is not exposed at surface. In study of existing alteration several methods such as remote sensing, studying of thin section and the chemical analysis of samples were used. Another issue that has taken into consideration in this paper is the magma mixing. This subject is confirmed by petrographic evidence such as sieve texture, corroded rims in primary phenocryst quartz, and hydrothermal effects on plagioclases especially in porphyritic andesites. Moreover, the extensive acidic rocks, notable alteration expanse, and also two generations of mineralization reveal assimilation in the studied area. This text has examined the similarities between Kahang and other porphyries in the Urumieh-Dokhtar zone.
M Abdi; M.H Karimpour; M.H Zarinkoob
Abstract
The main purpose of this study is processing of raw data by factor analysis method and having interpretation and integration them by geological, alteration and mineralization data. The distinctiveness of third factor of factor analysis for Au, Mo and W and the coincidence of third factor anomalies by ...
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The main purpose of this study is processing of raw data by factor analysis method and having interpretation and integration them by geological, alteration and mineralization data. The distinctiveness of third factor of factor analysis for Au, Mo and W and the coincidence of third factor anomalies by gold, high primary sulfide bearing area, secondary iron oxide and sericitic and silicic alterationrevealed that the third factor of factor analysis is the agent of mineralization in the study area. The suitable tectonic setting, shallow depth intrusiveswithintermediate composition, calc-alkalineand oxidant magmatism, anomaly of gold and disseminated mineralization in thehost rock and sulfide veinlet accompanied byabundant secondary iron oxide providedproperconditions for porphyry and epithermal type gold mineralization in the study area.
F. Khaleghi; Gh. Hosseinzadeh; I. Rasa; M. Moayyed
Abstract
The Syah kamar molybdenum deposit is a porphyry molybdenum system which has been explored during the recent research of author in the northwest of Iran and is being reported for the first time and its ore mineralization is explained and discussed in this paper on the basis of geological data, mineralization ...
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The Syah kamar molybdenum deposit is a porphyry molybdenum system which has been explored during the recent research of author in the northwest of Iran and is being reported for the first time and its ore mineralization is explained and discussed in this paper on the basis of geological data, mineralization evidences, geochemistry and fluid inclusions thermometry data. A porphyry quartz-monzonitic stock, which belongs to the K-rich (alkali-rich) calc-alkaline rock series and on the basis of geochemical data and tectonic setting viewpoint, formed as the post-collision granites is considered as the mineralization parent rock of this system. According to the emplacement pattern of productive intrusive bodies of the region, the mineralization of molybdenum have occurred after Eocene time, about the Oligocene time, and the mineralization process has taken place most probably at the last stage of magma emplacement, and on the basis of microthermometery and salinity data, its metaliferous hydrothermal solution have had low salinity and medium homogenization temperature. In addition, according to the host rock type, accompanying alterations and some other evidences, the mineralization characteristics of Syah kamar molybdenum prospect are comparable with the molybdenum deposits of the quartz-monzonitic type. During the tectonic processes, the ore-bearing hydrothermal solution ascended along weak zones and suitable fault structures, and intruded into the joints and fissures of surrounding rocks, and as a result of physiochemical changes of environment and some other effects, finally the Syah kamar molybdenum deposit has been formed.
S. Yousefifar; A. Khakzad; H. Asadi Harooni; M. R. Jafari; M. Vosoughi Abedin
Abstract
Dali porphyry copper-gold deposit is situated geologically incontact of the Urmieh-Dokhtar magmatic belt and the Sanandaj-Sirjan zone in central of Iran and for the first time this deposit was investigated with using the satellite image processing (TM). In this research, the Northern part of the Dali ...
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Dali porphyry copper-gold deposit is situated geologically incontact of the Urmieh-Dokhtar magmatic belt and the Sanandaj-Sirjan zone in central of Iran and for the first time this deposit was investigated with using the satellite image processing (TM). In this research, the Northern part of the Dali deposit has been investigated in order to recognize the potential copper and gold-bearing target areas. The survey layers include the lithologic units, alteration, geophysical and geochemical results, tectonics, and copper mineralization. As a accurate decision can have a considerable effect on exploration plans, so in this research efforts have been made to make use of new combination methods including index overlay method, fuzzy logic method, and the analytical hierarchy process. These three methods support and complement each other and have revealed highly potential copper and gold mineralization areas. Among these methods, Analytical hierarchy process is the best method for combining the exploration data in this area. The investigations (for instance field evidences of outcrops, mineralization and also sampling of 7 trenches) carried out in the study area confirm this matter. Based on achieved results, geological perspective in central of studied area is appropriate for continuing mining exploration, especially for subsurface exploration in future.
L. Ebadi; S.A. Alavi; Sh. Shafiei
Abstract
Hydrothermal vein and porphyry copper deposits are notable within Eocene volcanic rocks of Shahr-e-Babak area. In this paper, the structural patterns within Shahr-e-Babak area as well as the relationship between structural elements and the emplacement of dikes and hydrothermal vein and porphyry copper ...
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Hydrothermal vein and porphyry copper deposits are notable within Eocene volcanic rocks of Shahr-e-Babak area. In this paper, the structural patterns within Shahr-e-Babak area as well as the relationship between structural elements and the emplacement of dikes and hydrothermal vein and porphyry copper deposits have been discussed. Three fault trends of WNW-ESE and N-S are recognized in northeastern Shahr-e-Babak according to satellite images and field observations. The WNW-ESE and N-S trending faults are normal faults, while the NE-SW trending faults are sinistral faults with normal component. Two trends are recognized for the dikes in Shahr-e-Babak area namely, WNW-ESE(T2) and N-S (T1) following the trends of preexisting fractures in the area. The existence of an extensional system is recognized by the pattern of tension gashes and Pennant and the presence of extensional joints in the area. The shift in s1 direction from NE-SW to N-S, confirm the presence of some rotation in the area. The rotation in a transpressional regime caused the development of extensional structures in the Shahr-e-Babak area; the extensional structures provided the space for the passage of ore fluids and the emplacement of polymetallic vein and porphyry copper deposits in northeastern Shahr-e-Babak
M. Mohamadian; M. Boomeri; A. Ahmadi; A. A. Moridi Farimani; H. Daglas; M. Jamali
Abstract
Sungun Porphyry Copper Deposit is located about 130 km to the northeast of Tabriz, northeast Iran. This deposit contains 796 million tons of ore with 0.61% Cu, 0.01% Mo, 0.016 ppm Au, 9.75 ppm Bi and Re (0.09 wt% of molybdenite). This research studies the physico-chemical environment using the chemical ...
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Sungun Porphyry Copper Deposit is located about 130 km to the northeast of Tabriz, northeast Iran. This deposit contains 796 million tons of ore with 0.61% Cu, 0.01% Mo, 0.016 ppm Au, 9.75 ppm Bi and Re (0.09 wt% of molybdenite). This research studies the physico-chemical environment using the chemical properties of minerals of this deposit. This deposit is related to granodiorite-diorite dikes and granodiorite stock that intruded into sedimentary and volcanic rocks of Cretaceous and Eocene. Dominant alterations are potassic, phyllic, argillic and propylitic from center outward which are characteristics of continental margin porphyry copper deposits. Simultaneously with the supergene mineralization, an iron cap of iron oxides, iron hydroxides, copper oxides, sulfates, carbonates and copper phosphates were developed on top of the deposit and along the fractures. In conclusion, based on mineral chemistry, in 450 ºC and 0.5 kb pressure (PT condition of potassic zone), sulfur fugacity and pH is determined to be as: log¦S2=-18 to -24 an pH=2.5 to 7.5. In 350 ºC and 0.5 kb pressure (PT condition of phyllic zone), oxygen and sulfur fugacities are: logƒO2= -20 to -33 and log¦S2=-6 to -15.
N. Taghipour; A. Aftabi; M.R. Ramezani
Abstract
The Miduk porphyry copper deposit is located in 85 Km northwest of Sarcheshmeh porphyry copper deposit, Kerman province. The deposit is hosted by Eocene volcanic rocks of andesite-basalt composition. The porphyry-type mineralization is associated with two calc-alkaline intrusive phases (P1 and Miduk ...
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The Miduk porphyry copper deposit is located in 85 Km northwest of Sarcheshmeh porphyry copper deposit, Kerman province. The deposit is hosted by Eocene volcanic rocks of andesite-basalt composition. The porphyry-type mineralization is associated with two calc-alkaline intrusive phases (P1 and Miduk porphyry) of Miocene age. Five hypogene alteration zones are distinguished in the Miduk deposit, magnetite-rich potassic, potassic, potassic-phyllic, phyllic and propylitic. The main stage of mineralization consists of chalcopyrite, magnetite and anhydrite in potassic alteration zone. The mineralization is mostly associated with Miduk porphyry intrusive phase. Three different types of biotite including magmatic, magmatic affected by hydrothermal fluids and secondary are distinguished at the Miduk deposit. Magmatic type biotites affected by hydrothermal fluids and secondary biotites contain higher XMg values than the magmatic biotites. The XMg are positively correlated with Si, Al, Mg, K, Mg/Ti, but negatively correlated with Al×Ti, Fe, Na, Fe/Ti contents. The variations of Cu, Mo, Au and Ag are controlled by vein - type alteration and mineralization zones. The tonnage of deposit is about 170 Mt with average grade of 0.82 % Cu, 0.007% Mo, 82 ppb Au and 1.8 ppm Ag, respectively. Highest values of Mo and Au occur in leached and oxide, supergene sulfide mineralization, phyllic and potassic-phyllic alteration zones, respectively. Gold displays positive correlation with Cu in magnetite-rich potassic and potassic alteration zones. Based on petrography, mineralogy, alteration halos and patterns of Cu, Au, Ag and Mo, the Miduk porphyry copper deposit is similar to those of continental arc setting porphyry copper deposits.
