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Fluid Evolution of the Magmatic Hydrothermal Porphyry Copper Deposit Based on Fluid Inclusion and Stable Isotope Studies at Darrehzar, Iran  [PDF]
B. Alizadeh Sevari,A. Hezarkhani
ISRN Geology , 2014, DOI: 10.1155/2014/865941
Abstract: The Darrehzar porphyry Cu-Mo deposit is located in southwestern Iran (~70?km southwest of Kerman City). The porphyries occur as Tertiary quartz-monzonite stocks and dikes, ranging in composition from microdiorite to diorite and granodiorite. Hydrothermal alteration and mineralization at Darrehzar are centered on the stock and were broadly synchronous with its emplacement. Early hydrothermal alteration was dominantly potassic and propylitic and was followed by later phyllic and argillic alteration. The hydrothermal system involved both magmatic and meteoric water which were boiled extensively. Copper mineralization was accompanied by both potassic and phyllic alterations. Based on number, nature, and phases number which are available in room temperature, three types of fluid inclusions are typically observed in these veins: (1) vapor rich, (2) liquid rich and (3) multi phase. The primary multiphase inclusions within the quartz crystals were chosen for microthermometric analyses. Early hydrothermal alteration was caused by high-temperature, high-salinity orthomagmatic fluid and produced a potassic assemblage. Phyllic alteration was caused by high-salinity and lower-temperature orthomagmatic fluid. Magmatic and meteoric water mixtures were developed in the peripheral part of the stock and caused propylitic alteration which is attributed to a liquid-rich, lower temperature. 1. Introduction Due to their low metal grade and very large volume, porphyry-type deposits are described as disseminated and mineralization is, to a great extent, controlled by fractures and faults. Porphyry copper deposits are formed where magmatic-hydrothermal fluids are expelled from a crystallizing magma [1, 2] and initiated by injection of oxidized magma saturated with S- and metal-rich, aqueous fluids from cupolas on the tops of the subjacent parental plutons. The sequence of alteration-mineralization is principally a consequence of progressive rock and fluid cooling caused by solidification of the underlying parental plutons and downward propagation of the lithostatic-hydrostatic transition [3]. Cooling, depressurization, and reaction between the fluids and the wall rocks cause metals to precipitate in and around the fractures, forming veins with alteration envelopes. Alteration assemblages and associated mineralization in porphyry ore deposits develop from huge hydrothermal systems dominated by magmatic and meteoric fluids [4, 5]. Porphyry Cu systems host some of the most widely distributed mineralization types at convergent plate boundaries including porphyry deposits centered
Exploring Porphyry Copper Deposits in the Central Iran Using Remote Sensing Techniques  [PDF]
Akram Mahan, Ramin Arfania
Open Journal of Geology (OJG) , 2018, DOI: 10.4236/ojg.2018.86035
Abstract: This study used the ability of remote sensing technology to identify alteration zones in porphyry copper mining and Iron oxides of area in south Nain district in Iran by using Lands at-8 data source. The band ratio of 3/2 derived from image spectra was used to indicate the distribution of iron oxides and 6/3 for identifying gossan. Hydrothermal alteration mineral zones associated with porphyry copper mineralization identified and discriminated based on two algorithms of target detection, MTTCIMF and OSP. Those techniques identified porphyry copper mineralization in study area and six points were diagnosed as the best location for ore exploration. For more accurate study and recognition between mineralization and tectonic structure of district, the lineament map of area was produced by applying Gaussian high-pass filter on IRS data. The Spatial distribution of hydrothermal alteration zones has been verified by inspection in field works and Fuzzy logic. Results showed that image processing techniques have a great ability to obtain comprehensive information for reconnaissance stage of porphyry copper exploration in the case study and assist researcher to explore porphyry copper and iron oxides regions before time-consuming and costly ground investigation.
Geochemistry, Mineralization and Alteration Zones of Darrehzar Porphyry Copper Deposit, Kerman, Iran  [PDF]
R. Derakhshani,M. Abdolzadeh
Journal of Applied Sciences , 2009,
Abstract: The goal of this study is focused on alteration, mineralization and geochemistry of Darrehzar porphyry copper deposit which is situated in the Central Iranian Tectono-Volcanic Belt. This deposit is associated with an Oligocene granodiorite stock which intruded Eocene Volcano-Sedimentary and Cretaceous carbonate rocks. Four distinct types of hypogene alterations are recognized at Darrehzar: Potassic, Phyllic, Argillic and Propylitic. Copper mineralization was accompanied mainly by phyllic and to a lesser extent potassic, alteration. In the potassic alteration zone, enrichment of K and depletion of Na, Ca, Mn and Fe took place. These changes attended replacement of plagioclase and amphibole by K-feldspar and biotite respectively. Potassic alteration was associated with a major addition of Cu, as evident from the occurrence of disseminated chalcopyrite and bornite in this zone. Phyllic alteration was accompanied by depletion of Na, K, Fe and Ba and enrichment of Si and Cu. Losses of Na, K and Fe reflect sericitization of alkali feldspar and destruction of ferromagnesian minerals. The addition of Si is consistent with widespread silicification, which is a major feature of phyllic alteration, as well as the addition of Cu mobilized from the potassic zone. Pertographic studies of this porphyry copper deposit indicate that granodiorite association is mainly composed of plagioclase, quartz, orthoclase, biotite, sericite. The main mineralization-related alteration episodes (potassic, phyllic, argillic, propylitic) have been studied in terms of mass transfer and element mobility during the hydrothermal evolution of the Darrehzar copper deposit.
Fluid Inclusion Studies on Quartz Veinlets at the Ali Javad Porphyry Copper (Gold) Deposit, Arasbaran, Northwestern Iran  [PDF]
Behzad Hajalilou, Mehraj Aghazadeh
Journal of Geoscience and Environment Protection (GEP) , 2016, DOI: 10.4236/gep.2016.46007
Abstract: Ali Javad porphyry copper-gold deposit is located in Arasbaran porphyry copper belt at northwestern Iran, some 20 km east of Sungun Mine. Porphyry mineralization at the Ali Javad deposit occurred in post-Oligocene quartz monzonite bodies which intruded in the Eocene volcanic rocks. Mineralization occurred as veins, veinlets and dissemination both as hypogene and supergene type. Several types of veinlets were distinguished during the study of the deposit. Fluid inclusion studies on fluids trapped in quartz which were taken from drill core samples indicated a wide range of homogenization temperature in the veinlets from 138°C to 565°C which their salinity demonstrated 33 - 61 wt% NaCl equivalent. Mineralizing fluids density at the deposit was 0.8 - 1.2 g/cm3. Fluid inclusion studies suggested that Ali Javad deposit is an Au-rich porphyry copper deposit; its fluid inclusion features were comparable with other porphyry deposits.
Application of Airborne Geophysical and ASTER Data for Hydrothermal Alteration Mapping in the Sar-Kuh Porphyry Copper Area, Kerman Province, Iran  [PDF]
Mehdi Honarmand
Open Journal of Geology (OJG) , 2016, DOI: 10.4236/ojg.2016.610092
Abstract: Known deposits are appropriate sites for investigating significant exploratory keys that could be helpful in mineral exploration in corresponding regions or similar areas. This study was performed to delineate hydrothermal alteration model and some geophysical characteristics of the SarKuh porphyry copper deposit located within the southern part of the central Iranian Cenozoic magmatic belt (CICMB). Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) images have been used to produce hydrothermal alteration map using a fractal-aided spectral angle mapper (SAM) method. Airborne data were used to study magnetic-radiometric properties of the deposit. Image processing of ASTER images and laboratory studies proved the presence of two types of phyllic ale ration called intense and weak phyllic based on abundance of sericite mineral. It realized that radiometric anomalies of 40K, eTh and eU are limited to boundary of phyllic zone. Radiometric ratios e.g. eTh/40K were good enough to enhance phyllic zone.
Using ETM+ and Airborne Geophysics Data to Locating Porphyry Copper and Epithermal Gold Deposits in Eastern Iran  [PDF]
M.H. Karimpour,A. Malekzadeh Shafaroudi,C.R. Stern,M.R. Hidarian
Journal of Applied Sciences , 2008,
Abstract: Enhanced Thematic Mapper Plus (ETM+) and airborne geophysics data have been used for locating porphyry copper and epithermal gold prospect areas related to hydrothermal alteration zones in the Lut block of eastern Iran. The Lut block has a great potential for different types of mineralization due to its extensive exposure of Cenozoic volcanic and subvolcanic calc-alkaline rocks generated in a subduction zone tectonic setting. Various ETM+ images processing techniques were employed, including false color composite images, color composite ratio images, standard PC image analysis on six bands and color composite selective PC images. Application of these techniques detected four major prospect areas and also identified another small previously unknown alteration area in the southeastern part of the district. Color composition selective PC images proved to be the most reliable method for exploration. Airborne magnetometry data show high magnetism over the most of the study area, resulting from the presence of magnetic-series granitoid rocks and/or propylitic/potassic alteration zones with magnetite veins related to mineralization. Low magnetic areas reflect intense magnetic destruction in other types of alteration zone. Radiometry detected areas of high K and U counts that have resulted from the presence of sericite, clay minerals and K-feldspar in alteration zones with low magnetism.
High magma oxidation state and bulk crustal shortening: key factors in the genesis of Andean porphyry copper deposits, central Chile (31-34°S)
Garrido,Iván; Cembrano,José; Si?a,Armando; Stedman,Peter; Yá?ez,Gonzalo;
Revista geológica de Chile , 2002, DOI: 10.4067/S0716-02082002000100003
Abstract: abstract the andean segment between 31 and 34°s documents a unique tertiary tectono-magmatic evolution that involves the generation of three world-class late miocene porphyry copper deposits: los pelambres, río blanco-los bronces and el teniente. the genesis of these giant ore-deposits occurred during a major copper mineralization cycle that took place progressively from north to south, in close association with the emplacement of a series of calc-alkaline, highly oxidized granitoids (fe2o3/feo = ratio between 1 and 3). these granitoids were emplaced coevally with bulk shortening and appear to have fractionated along active steep, margin-oblique fault zones that may have played a key role in the exsolution process of mineralized hydrothermal fluids. an increasing contamination of the mantle source by components from altered oceanic crust beneath the arc could account for a rise in the oxidation state of the magmas without producing a significant increase in the 87sr/86sr initial ratio, as suggested by new and previously published geochemical data. the authors propose that this increasing supply of oceanic crust components to the miocene magmas could be linked to the progressive subduction of the juan fernández ridge from north to south
Adakite versus porphyry copper and epithermal gold deposits: a possible metallogenetic specialization of magmatism required in-deep assessment
埃达克岩与Cu-Au成矿作用:有待深入研究的岩浆成矿关系

LIU HongTao,ZHANG Qi,LIU JianMing,YE Jie,ZENG QingDong,YU ChangMing Institute of Geology,Geophysics,Chinese Academy of Sciences,Beijing,China,
刘红涛
,张旗,刘建明,叶杰,曾庆栋,于昌明

岩石学报 , 2004,
Abstract: It has been revealed that most world-class porphyry copper and epithermal gold deposits of Cenozoic age around Pacific Rim, such as those occurred in the Central Andes and the Philippines, are spatially and temporally associated with contemporaneous adakitic magmatism. Adakite and its clan (such as high magnesian andesites (HMA) , magnesian andesite (MA) , Niobium-enriched basalts (NEB), and high Niobium basalts, etc. ) are the host rocks of most porphyry copper deposits, and the source rocks of many epithermal Au systems. Based on the present level of understanding, the genetic relationship between them may stem from the inherent natures of adakitic magmas with sufficient fluids, high oxygen fugacity and mafic source region, which are preferred for Cu, Au and other deeply-sourced metals to be extracted and enriched, and finally economically mineralized. However, the reason (s) and mechanism responsible for this relationship are poorly understood in general. It is suggested that the close link of adakites with porphyry copper and epithermal gold deposits be a potential metallogenetic specialization of magmatism that necessitate in-deep assessment and relevant comparative studies among ore-bearing adakites, barren adakites and normal calc-alkaline rocks, to uncover the intrinsic and concealed story.
High magma oxidation state and bulk crustal shortening: key factors in the genesis of Andean porphyry copper deposits, central Chile (31-34°S)  [cached]
Iván Garrido,José Cembrano,Armando Si?a,Peter Stedman
Revista geológica de Chile , 2002,
Abstract: ABSTRACT The Andean segment between 31 and 34°S documents a unique Tertiary tectono-magmatic evolution that involves the generation of three world-class Late Miocene porphyry copper deposits: Los Pelambres, Río Blanco-Los Bronces and El Teniente. The genesis of these giant ore-deposits occurred during a major copper mineralization cycle that took place progressively from north to south, in close association with the emplacement of a series of calc-alkaline, highly oxidized granitoids (Fe2O3/FeO = ratio between 1 and 3). These granitoids were emplaced coevally with bulk shortening and appear to have fractionated along active steep, margin-oblique fault zones that may have played a key role in the exsolution process of mineralized hydrothermal fluids. An increasing contamination of the mantle source by components from altered oceanic crust beneath the arc could account for a rise in the oxidation state of the magmas without producing a significant increase in the 87Sr/86Sr initial ratio, as suggested by new and previously published geochemical data. The authors propose that this increasing supply of oceanic crust components to the Miocene magmas could be linked to the progressive subduction of the Juan Fernández Ridge from north to south RESUMEN Alto estado de oxidación magmático y acortamiento regional: factores claves en la generación de los pórfidos cupríferos de Chile central (31-34°S). El segmento andino comprendido entre los 31 y 34oS documenta una evolución tectono-magmática que involucra la generación de tres pórfidos cupríferos de clase mundial: Los Pelambres, Río Blanco-Los Bronces y El Teniente. La génesis de estos tres depósitos gigantes habría ocurrido como la culminación de un ciclo de mineralización que actuó progresivamente de norte a sur, en estrecha asociación con el emplazamiento de granitoides calcoalcalinos, fuertemente oxidados (razón Fe2O3/FeO = entre 1 y 3). Estos granitoides fueron emplazados en un ambiente de acortamiento regional y se fraccionaron a lo largo de zonas de falla sub-verticales activas, oblicuas al margen continental. Se propone que la actividad de estas zonas de cizalle habría jugado un rol clave en la exsolución de los fluidos mineralizadores. El elevado estado de oxidación de los magmas, junto con la ausencia de un aumento significativo en las razones iniciales 87Sr/86Sr, respaldados por nuevos datos geoquímicos y por datos previamente publicados, podría ser el resultado de un aumento de componentes de corteza oceánica alterada en la fuente mantífera de los magmas, bajo el arco. Se propone que este incremento de
Geochemical Indicators of Porphyry Copper Deposits in the Dobzha Ore Concentration Area, Tibet
西藏多不杂矿集区斑岩铜矿地球化学指标研究

WU De-xin,ZHAO Yuan-yi,LIU Chao-qiang,XU Hong,LI Yu-chang,LI Yu-bin,LEI Xiao-guang,
吴德新
,赵元艺,刘朝强,许虹,李玉昌,李玉彬,雷晓光

地球学报 , 2012,
Abstract: The Dobzha ore-concentration area in northern Geize County of Tibet is composed of superlarge porphyry copper deposits discovered in recent years. In an area 30 km long in EW direction and 10 km wide in NS direction with Dobzha as the center, there are seven copper deposits, i.e., Dobzha, Bolong, Sena, Nadun, Naruo, Gaerqin and Tiegelong. On the basis of previous work and through the rotating orthogonal factor analysis of geochemical data of the core rock samples and the correlation analysis between the metallogenic elements such as Cu and rare earth elements La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y and trace elements U and Th, the authors have found that LREE and HREE show relative enrichment in the position of Cu ore (mineralization) body, so do trace elements U and Th , especially Th, which show some positive correlation with Cu with the increasing drilling depth. It can be inferred that the rare earth elements and trace elements U and Th might serve as potentially effective geochemical indicators in mineral exploration.
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