Economic Geology
Sholeh Malekshahi; Masoumeh Khalajmasoumi; Hadi Mohammad- Doost; Mona Sojdehee; Shahrzad Aboutorab
Abstract
The Sarkuh Porphyry Copper deposit is located about 6 km southwest of Sarcheshmeh porphyry copper deposit. Alterations in the region include advanced potassic, propylitic, phyllic and argillic. Copper mineralization is mainly associated with porphyry granodiorite mass. Minerals include chalcopyrite, ...
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The Sarkuh Porphyry Copper deposit is located about 6 km southwest of Sarcheshmeh porphyry copper deposit. Alterations in the region include advanced potassic, propylitic, phyllic and argillic. Copper mineralization is mainly associated with porphyry granodiorite mass. Minerals include chalcopyrite, pyrite, magnetite and some molybdenite. Fluid inclusion studies were performed on quartz from the sulfide viens of the potassic fraction and showed that the main mineralization phase was present with a homogenization temperature between 250 and 527 ° C, salinity between 13.6 and 52.9 wt٪ NaCl, has a high salinity in Sarkuh deposit (Orthomagmatic phase and hypogene mineralization). The homogenization temperature in the late stages of the receding phase (convective phase and the influence of atmospheric waters in the hydrothermal cycle) is around 132 to 165 degrees Celsius and its salinity is 0.005 to 4.74% equivalent to the weight of NaCl. The observed salinity variation can be attributed to the boiling event. The investigation of sulfur isotope composition on pyrite and chalcopyrite minerals in Sarkoh deposit was between +1 and 2.7‰, which indicates the magmatic source of sulfur. The stable oxygen isotope data on quartz veins, show positive range between 7.6 to +9.3‰ with an average of +8.5, indicates a magmatic source for hydrothermal fluids. Also, due to the limited range of sulfur isotopic composition, it can be concluded that the isotopic composition of sulfur has not undergone changes or contamination by other sources of sulfur, or the mixing of magmatic fluid with other sources has been very insignificant. Isotopic thermometry shows the temperature of 315°C and 476°C for the pair of pyrite-chalcopyrite minerals.
Economic Geology
Shahram Mobaser; Taher Farhadinejad; Abbas Asgari; Mohammad Ali Ali Abadi; Shirin Fatahi
Abstract
The Barzavand copper deposit with Oligocene age located in 30 Km northeast of Zefreh along a tension fault with W-E trend and developed within basaltic lava with stratabound form. Alterations mainly include: pyritization, propylitization, zeolitization, silicification, saussuritization and uralitization ...
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The Barzavand copper deposit with Oligocene age located in 30 Km northeast of Zefreh along a tension fault with W-E trend and developed within basaltic lava with stratabound form. Alterations mainly include: pyritization, propylitization, zeolitization, silicification, saussuritization and uralitization of basaltic lava. Furthermore geochemical studies in Barzavand show enrichment of SiO2, Al2O3, K2O, Na2O, P2O5, TiO2, ∑REE, Ag, As, Ba, Be, Bi, Cd, Cs, Cu, Li, Mo, Nb, Pb, Rb, Sb, Se, Sn, Sr, Ta, Tl, Te, Th, U, W, Y, Zn and Zr, enrichment- depletion of CaO, Fe2O3, MnO, Hf, Sc and V and depletion of S, Ni, Cr, MgO and Co during alteration. The positive correlation between (La/Lu)N, (La/Yb)N, (La/Sm)N and (La/Y)N and CaO (r= 0.70 to 0.96) indicate propylitization of host rock basalt and increase in pH of fluid responsible for mineralization that play important role in differentiation of lanthanides in study area. Ore minerals include chalcopyrite, bornite, covellite, azurite, malachite, hematite, goethite and pyrite. Copper is transported by means of chloride complexes into oxidized brines water related to late diagenesis stage and precipitated by substitution within pyrites formed during the volcanism process. It seems that the Barzavand copper deposit has submarine volcanism, early and late diagenesis, burial metamorphism and weathering stages during its evolution. According to alteration properties, mineralogy and the whole rock geochemistry, the Barzavand copper deposit is most similar to Manto type copper deposits.
Remote Sensing
mohammad sharifikia; jalal karami; Ehsan Falahati
Abstract
Optical Remote Sensing is a low-cost and efficient method to alteration zone detection. However in the area that have been covered by vegetation or alluvial, the identification of these areas is not very accurate with optical images. In this study fusion and integrating of ALOS-PALSAR L-band and ASTER ...
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Optical Remote Sensing is a low-cost and efficient method to alteration zone detection. However in the area that have been covered by vegetation or alluvial, the identification of these areas is not very accurate with optical images. In this study fusion and integrating of ALOS-PALSAR L-band and ASTER data by HSV, HSL, Maximum Likelihood and Artificial Neural Network has been done to discover and enhance the Argilic and Propylitic Alteration zones over the west part of Qazvin province in IRAN. For this purpose, Argilic and Propylitic alterations were primary identified unseeing ASTER image. Then based on geological data and field study, some areas with alterations covered by quaternary sediments, not detectable by ASTER images, were identified. In the following, the integration of the ALOS PALSAR L-band data and the ASTER SWIR bands with HSV, HLS, Maximum Likelihood and Artificial Neural Network were performed. The results of this study showed that the radar and optics data fusion, using HSV and HLS methods, increases the enhancement of visible argillic alteration zones in the study area. Also, the integration of radar and optics data with the Maximum Likelihood and the Artificial Neural Network methods,
Economic Geology
jahangir esmaeili; ahmad khakzad; mansor vosoghi abedini
Abstract
This area has been located in a scene ETM No. 164-37 and ASTER linear band prediction satellite image No. AST-L1A:002:ASTL1A 0108220733380109011021. Such measured images in different band combinations will be used for extracting of geological structures and types of alterations (iron oxide, Argillite ...
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This area has been located in a scene ETM No. 164-37 and ASTER linear band prediction satellite image No. AST-L1A:002:ASTL1A 0108220733380109011021. Such measured images in different band combinations will be used for extracting of geological structures and types of alterations (iron oxide, Argillite and Carbonate) and for detecting different stones and minerals of the ground, a spectrum range of 1.5 to 2.5 μ is very important.This range includes short to average IR range covering six linear band predictions (SWTR bands). On the other side, to use spectral reflectance curves of such minerals in USGSENVI spectral library for spectral analysis, it is necessary to resample the curves to the spectral range of ASTER. Linear Band Prediction methods, LS-Fit, Matched Filtering and BandRATIO used of ASTER images for all Minerals and iron alterations and for iron oxides there were also used visual interpretations and ETM images were used in band combination of RGB:531. Considering the petrological and geological situation of studied area (Scale 1:25000 of Kamoo), the type of Alteration and its index minerals detailed as below; Alteration of iron (Gotit, Hematit and Jarosit and Limotit), alteration of Argilic (Kaolinite, Motmorilonit, Ilite and Haloysite) and carbonate (Calcite and Dolomite) have been considered. Alterations present in remote sensing studies are in conformity with field and results obtained fromtypes of analysis conducted.
Remote Sensing
Seyedeh Sakineh Mousavi; Mehdi Honarmand; Hadi Shahriari; Mahdiye hosseinjanizadeh
Abstract
Mineral exploration in Esfandagheh area, located in south east of Kerman province is complicated due to verity of metallic deposits including volcanogenic massive sulfide copper, skarn iron, and volcanic manganese. This research was carried out with the aim of defining a model for mineral exploration ...
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Mineral exploration in Esfandagheh area, located in south east of Kerman province is complicated due to verity of metallic deposits including volcanogenic massive sulfide copper, skarn iron, and volcanic manganese. This research was carried out with the aim of defining a model for mineral exploration and providing mineral potential map using remote sensing data. ASTER and OLI images along with various image processing techniques including color composite of band ratios, principal component analysis (PCA), and QI and SI indices were applied to recognize the hydrothermal alteration halos. Result validation was done through field and laboratory studies. Argillic, phyllic, propylitic, and iron oxides/hydroxides alterations were enhanced using color composite ratios of ASTER bands like (B4+B7)/B6 in red, (B4+B6)/B5 in green, and (B7+B9)/B8 in blue. Hydrothermal alteration mapping was also accomplished using selected PCA of OLI 2, 4, 6, and 7 bands, ASTER 4 to 9 bands and a combination of OLI 2 and 4 bands along with ASTER 4 to 9 bands. ASTER thermal infrared bands applied to determine QI and SI indices for enhancing silicic halos. Mineral potential map was produced through integrating alteration maps by fuzzy logic method in which seven areas were identified such as Sargaz Kuh copper mine, Hossein Abad manganese mine, and Esfandagheh iron mine. Results showed the possibility of establishing mineral exploration model and producing mineral potential map in reconnaissance and prospecting stages using appropriate sensors and image processing techniques.
Remote Sensing
N. Namazi; M. R. Jafari; A. R. Jafari Rad; A. Khakzad
Volume 29, Issue 113 , November 2019, , Pages 221-228
Abstract
The study area (Pasghaleh) is located North of Tehran and is part of the Central Alborz Mountain Range. Pasghaleh deposit between coordinates 51º 25´15 ̎ up to 51º 25´ 54̎ Eastern longitude and 35º 49´42 ̎ up to 35º 50´15 ̎ Northern latitude in North ...
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The study area (Pasghaleh) is located North of Tehran and is part of the Central Alborz Mountain Range. Pasghaleh deposit between coordinates 51º 25´15 ̎ up to 51º 25´ 54̎ Eastern longitude and 35º 49´42 ̎ up to 35º 50´15 ̎ Northern latitude in North of Tehran, in the geological sheet with a scale of 1:100000 Tehran and is located East of the Pasghaleh village. Intrusive bodies in this area with age after the Eocene in penetrating Eocene volcanic and pyroclastic units and have altered these units. For mapping minerals and explore the alteration patterns together with Polymetal mineralization in the metallogenic zone Pasghaleh, for sine satellite ASTER and ETM spectral processing and interpretation. According to remote sensing data, it leads to the appearance of Kaolinite and Montmorillonite minerals (Argillic alteration index), Chlorite, Epidote and Calcite (Propylitic alteration index), Muscovite (Sericite alteration index) and Gossan in the range studied. Major mineralization in the region in acid Tuffs altered and scattered. The lithology of this region including pyroclastic rocks of Karaj Formation with Eocene age. Sulfuric minerals observed Pyrite, Chalcopyrite, Sphalerite and Galena. In the whole region Pyrite expands but Lead mineralization, Zinc, Copper, Gold and Silver which process is parallel to the general layering of classes Tuff Silica altered- Feldspathic- Pyrite slightly observed. Pyrite form syngenetic among the Tuffs.Tuffs in formation stage and in the stage of diagenesis, the alteration process Sericitic, Kaolinite and or Chlorite have tolerated. In terms of construction, altered zone mineralize Pasghaleh as a lens and layers plate form between rock units Dacite, Rhyodacite are formed. Based on the study of remote sensing data, presence of alterations Sericite, Argillic and Propylitic (the presence of Chlorite and Epidote) proven in the region, consequently by putting together these alterations to one another, it can be attributed to the alteration pattern of Kuroko Massive sulfide deposits.
Razieh Rezaei Hamid; Ebrahim Tale Fazel; Shojaedin Niroomand
Abstract
The Baharieh copper deposit with 1 Mt Cu ore, is located in 30 km of NE Kashmar city and it’s belong to Sabzevar zone and Taknar metallogenic area. The copper mineralization as stratabound and 200m length with east-west trending which occurs in porphyric andesitic tuff (middle Eocene). Volcanic ...
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The Baharieh copper deposit with 1 Mt Cu ore, is located in 30 km of NE Kashmar city and it’s belong to Sabzevar zone and Taknar metallogenic area. The copper mineralization as stratabound and 200m length with east-west trending which occurs in porphyric andesitic tuff (middle Eocene). Volcanic to subvolcanic rocks are composed of andesite, dacite and rhyolite and shows calc-alkaline to shoshonitic affinities. According to geochemistry of immobile trace elements (e.g., La, Yb and Zr), the igneous rocks straddle within active continent margin arcs. The vein minerals consist of main sulfide minerals such as chalcopyrite and pyrite, which accompanied with bornite, covelline, and chalcocite. Silicic, calcitic, chloritic and argillic are the main alteration assemblage with mineralization. Two types of fluid inclusions including of liquid-rich (LV-type) and vapor-rich (VL-type) are distinguished in quartz-ore stage of the Baharieh deposit. Homogenization temperature and salinity are recorded varies from 187 to 356°C and 0.99 to 18.7 wt% NaCl eq. Some characteristic as vein, breccia and vuggy textures, volcanic host rocks, low temperature alteration, simple ore minerals and high chalcopyrite content, temperature and salinity of fluids and the other evidences shows Baharieh copper deposit is similar to in Cu (Ag) manto-type (volcanic red bed) deposit at Chile.
J. Rasouli; M. Gorbani
Abstract
Delfard area is located in the northwestern of Jiroft, formed the northwestern part of the Jabālbārez granitoid complex, in Uromiyeh- Dokhtar magmatic belt. The Jabālbārez granitoid complex has a wide range of rocks inclusive from diorite to alkali granite, which were formed by magmatic differentiation ...
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Delfard area is located in the northwestern of Jiroft, formed the northwestern part of the Jabālbārez granitoid complex, in Uromiyeh- Dokhtar magmatic belt. The Jabālbārez granitoid complex has a wide range of rocks inclusive from diorite to alkali granite, which were formed by magmatic differentiation process over the several course of consecutive pulses. Last pulses are masses of porphyry that showed evidence of copper mineralization. One of these intrusive bodies is Delfard. Copper mineralization in Delfard area is more important than other parts of Jabālbārez. Consequently, in the area, three porphyry masses showing the evidence of porphyry copper mineralization. Chalcopyrite, Pyrite, Malachite, Azurite and Magnetite are indicative minerals. Alteration zones in Delfard area are silicic, potassic, arjelic, phyllic, and propylitic that can be correlated with Lovell and Gilbert model. According to studies, Delfard has high potential for exploration and drilling. The average copper content in the ore is about 1800 ppm. Petrogenesis review of the mafic rocks in Delfard area shows that these rocks originated from a richer source than NMORB. In addition, the rocks of Delfard area are Flux melting pointer that happened in the subduction of oceanic crust under the adjacent crust. In other words, the sequence of calc-alkaline rocks of Delfard area attributed to compressional tectonic regime that intrusived and erupted along the Uromiyeh- Dokhtar zone with development and high volume in the form of magmatic horizons. Finally, petrogenesis of studied granite series is similar to the calc-alkaline granitoids, which was originated from basaltic magma mantle metasomatised by fluids from the subducted slab. Based on zircon U-Pb geochronology,the age of Delfard granitoid is 15/83±1/3 Ma. One can imagine that, magmatic differentiation process was completed in a short time and intrusive body was sequentially penetrated and placed in the earth's crust in a short time.
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.
S Aghajani Marsa; M Emami; M Lotfi; k Gholizadeh; M Ghasemi Siani
Abstract
The mineralized veins at Nikuyeh are located south of the Tarom-Hashtjin metallogenic province in Alborz-Azarbayejan belt (West Alborz). Rhyodacite and andesite/andesitic basalt volcanic rocks are hosting the vein mineralization in the Nikuyeh ore district. Hydrothermal alteration in host rocks consists ...
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The mineralized veins at Nikuyeh are located south of the Tarom-Hashtjin metallogenic province in Alborz-Azarbayejan belt (West Alborz). Rhyodacite and andesite/andesitic basalt volcanic rocks are hosting the vein mineralization in the Nikuyeh ore district. Hydrothermal alteration in host rocks consists of propylitic, sericitic, argillic and silicic. Mineralization in Nikuyeh occurs in both hypogene and supergene forms in three stages: early stage includes pyrite, magnetite, chalcopyrite and bornite; middle stage includes galena, sphalerite and minor chalcopyrite, and late stage includes malachite, cerussite, covellite, hematite and goethite. Fluid inclusion studies on quartz and calcite show homogenization temperatures ranging between 185°C to 312°C and 133°C to 251°C, respectively. The salinities range from 0.5 to 5.5 wt% NaCl eq. in quartz and 0.3 to 5.4 wt% NaCl eq. in calcite. Boiling is supported by the occurrence of coexisting vapor-rich and liquid-rich inclusions, hydrothermal breccias, microcrystalline quartz, chalcedony and bladed calcite. Boiling and cooling are considered as the main mechanisms for ore deposition. Ore mineralogy, alteration assemblages and fluid inclusion data allow mineralization in Nikuyeh ore district to be classified as low sulfidation epithermal type.
H Zamanian; Sh Rahmani; M.R Jannessary; R Zareii Sahamiieh; B Borna
Abstract
Lohneh gold and copper deposits lay in the north west of Iran, 100 kilometers north of Zanjan province. Lohneh mining area is a part of the Tarommetallogenic zone in the Alborz-Azerbaijan region. The presence of numerous minerals, slag melting of mining activities (such as cows and exploratory pits, ...
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Lohneh gold and copper deposits lay in the north west of Iran, 100 kilometers north of Zanjan province. Lohneh mining area is a part of the Tarommetallogenic zone in the Alborz-Azerbaijan region. The presence of numerous minerals, slag melting of mining activities (such as cows and exploratory pits, tunnels) in the Armenian fortress (by Armenian miners) shows that the mineral reserve Lohneh have been considered by old miners. There are 9 gold bearing quartz veins .Two main quartz vein with a length of 500 meters and a width of one meter (visible on the Earth). Rock outcrops in the area consist of the Eocene-Oligocene volcanic rocks (tuffs, tuff breccia, trachyandesite) and intrusive rocks (granodiorite, quartz monzonite, monzonite). On the basis of geochemistry study, intrusive rocks is resemble the I-Type granitoids and from a magmatic stand point, the rocks of the area are calc–alkaline, and tectonically they belong to the continental margin and subduction zones. Tuff breccia rocks cut by quartz monzonite and has been altered. The major alteration of the areas consists of silicious, sericitic, and argillic alteration. The main gold minerals have occurred in tuff breccia rocks and a small amount of gold mineral in quartz monzonite. Gold mineralization in the Lohneh area is in the form of open space, vein-veinlet and hydrothermal breccia. According to chemical analysis of gold mineralized samples gold grade is in the range of at least 0.002 to 10ppm. The average gold grade is 4.35ppm. Mineralogy of Lohneh deposit has a metallic minerals (oxide, sulfide) and non-metallic (silicate and carbonate) which is composed of two phases hypogene and supergene. Metallic minerals are including gold particles (free in siliceous gangue and visible under a microscope and SEM study), silver (in the free form in siliceous and involved in galena and tetrahedrite network), pyrite, chalcopyrite, bornite, galena, sphalerite, and tetrahedrite. Non-metallic minerals or gangue consist of quartz, hydrothermal alkali feldspar (adularia), sericite, clay minerals, calcite, and small amount of barite. According to geochemical studies (table correlation of elements, graph clustering and component plot in rotated space) gold with Ag(0.78), cu(0.81), As(0.7), Pb(0.64), Zn(0.6), S(0.4), Bi(0.45), U(0.3), Mo(0.25) is a significant correlation. This correlation geochemistry is corresponded with mineralography evidence (mineral paragenesis sequence) and SEM studies. Fluid inclusion study was performed on primary, large size and rich liquid fluid inclusions on quartz mineral (concurrent with the formation of gold and sulfide minerals).Fluid inclusion data shows in the temperature range from 125 to 290 °C and salinity between 1 and 6.5 wt% NaCl and depths less than 1000 m. Fluid inclusion evidence shows cooling effect, boiling and formation of solutions with high salinity and density of the ore forming fluids in Lohneh deposits. Adularia mineral, calcite, bladed and comb quartz and hydrothermal breccia are evidence of boiling effect in the Lohneh deposits.Evidence of the presence of epithermal textures (banded, comb, blade, and hydrothermal breccia), sericitic alteration, and sulfide minerals such as galena, sphalerite, chalcopyrite, tetrahedrite, and fluid inclusions evidence (temperature, salinity, density, vapor-rich inclusions) indicates intermediate sulphidation epithermal gold deposits in Lohneh area.
Sh Fatahi; A.A Calagari; A Abedini
Abstract
Neyestanak bentonite deposit is located in northwest of Naeen, Isfehan province. This deposit is an alteration product of Oligocene tuff breccias. Mineralogical considerations of this deposit show that montmorillonite, kaolinite, and quartz are the principal minerals which are accompanied by lesser amounts ...
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Neyestanak bentonite deposit is located in northwest of Naeen, Isfehan province. This deposit is an alteration product of Oligocene tuff breccias. Mineralogical considerations of this deposit show that montmorillonite, kaolinite, and quartz are the principal minerals which are accompanied by lesser amounts of anorthite, calcite, chlorite, illite, albite, dolomite, microcline, orthoclase, sanidine, and halite. Mineral chemistry investigations testify to the similarity of this deposit with Wyoming-type bentonite deposits. Geochemical studies reveal that bentonitization of tuff breccias at Neyestanak is accompanied by depletion of Ba, Co, Zn, Y, Ni, Sr, Au, Ca, Fe, Mg, Mn, P, Ti, and Na, enrichment of Si, Th, As, Hf, Nb, and U, and leaching-fixation of K, Pb, Cs, Rb, Zr, and Cu. Geochemical analyses make clear that variation of Eu and Ce anomalies in this deposit were controlled by the degree of alteration of feldspars and oxidation potential of the environment, respectively. By considering the results obtained from this study, it seems that factors such as differences in degree of alteration intensity of parent materials, physico-chemical conditions of the environment, adsorption, incorporation in crystal structure, access to complexing ligands, and differences in degree of resistance of the primary minerals against alteration played prominent role in mobilization, distribution, and concentration of elements in this deposit.
R Ferdowsi; A.A Calagari; M.R Hosseinzadeh; K Siahcheshm
Abstract
Astarghan area is located in ~ 50 km of north of Tabriz, southeast of Kharvana, East-Azarbaidjn. The area is a part of Gharadagh- Arasbaran metallogenic belt. The most important units in the area is a hypabyssal prophyritic to granular granodioritic intrusive body of Oligo-Miocene and flysch- type sedimentry ...
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Astarghan area is located in ~ 50 km of north of Tabriz, southeast of Kharvana, East-Azarbaidjn. The area is a part of Gharadagh- Arasbaran metallogenic belt. The most important units in the area is a hypabyssal prophyritic to granular granodioritic intrusive body of Oligo-Miocene and flysch- type sedimentry sequence of limestone, limy sandstone and marl (Paleocene-Eocene). Intrusion of the stock into the sedimentary rocks caused them to convert into a series of metasomatites and contact metamorphic rocks. Geostatistic studies on stream sediments and heavy mineral were done and include data processing, (i.e. normalization, univariate and multivariate analysis), and ultimately preparation of anomaly maps. The correlation coefficients among elements were determined. Elements that show positive correlations with gold are Cu, Hg, Pb, As, Sb, Ag, Bi and Mo. The results of preliminary regional geochemical explorations have led to discovery of two anomalous zones for gold; grade 1 and grade 2. The anomalies were verified by studies on heavy minerals in stream sediments and mineralized and altered samples taken from gold anomalous zones. The most important indentified heavy minerals include magnetite, malachite, gold, micaseous hematite, pyrite, galena, cerussite, pyrite- limonite, goethite, limonite, barite, hematite, pyrite- oxide which are affiliated with alteration and mineralzation zones. The major alterations in the area are argillic, sericitic and propylitic developed along the vein’s walls. Field and analytic studies done on samples taken from the gold anomalous zones led to identification of epithermal gold veins having over 4.5 ppm gold grade. The concordance of anomaly map with tectonic map and altered zones indicate that the faulted and fractured zones have played a crucial role in creation of gold anomalous zones. The incorporation of these data in the area led to introduction of several anomalous zones belonging to Au, Ag, Cu, As and Pb that can be used as passfinders for epithermal gold.
Z Yazdi; A.R Jafari Rad; H Kheyrollahi
Abstract
In this research, the areas for prospecting porphyry copper deposits have been introduced using airborne geophysical data (magnetic and radiometric). Magnetic anomaly boundaries have been detected using the reduction to the pole (RTP), upward continuation (with different heights), horizontal derivative ...
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In this research, the areas for prospecting porphyry copper deposits have been introduced using airborne geophysical data (magnetic and radiometric). Magnetic anomaly boundaries have been detected using the reduction to the pole (RTP), upward continuation (with different heights), horizontal derivative (HD) and tilt angle filters to estimate approximate depth of magnetic structures. In addition, the felsic intrusives and potassic alteration zones have been determined using radiometric data and the obtained ternary map. Finally, due to genetic model of porphyry copper deposits and effective factors on mineralization and integration magnetic and radiometric data results, the Chahargonbad region has been categorized according to the priority of the porphyry copper mineralization. The most favorable areas are located in north, center and east of study area.
M Maanijou; N Puyandeh; A.A Sepahi; S Dadfar
Abstract
The study area is located at 42 km NE of Qorveh city, in KordestanProvince and in the Metamorphic– Magmatic Sanandaj-Sirjan Zone. There are other important gold mines such as the Zarshouran and Aghdarreh mines in this zone. The most important alterations of the region are sericitic (phyllic), argillic, ...
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The study area is located at 42 km NE of Qorveh city, in KordestanProvince and in the Metamorphic– Magmatic Sanandaj-Sirjan Zone. There are other important gold mines such as the Zarshouran and Aghdarreh mines in this zone. The most important alterations of the region are sericitic (phyllic), argillic, silicification and propylitic respectively. Therefore, in this research, the phyllic and argillic alterations were the main purpose and by using different techniques of images processing of satellite images such as: False Color Composition, Band Ratio, Principal Component analysis, Crosta and finally by Spectral Angle Mapper methods iron oxides and development of alterations have been recognized. For accuracy between field evidences and results of software processing, X-Ray Diffraction analysis were used for controlling and recognizing the index minerals of each zone. Then, the comparison between standard and the study area curves were done to confirm the obtaining results. Finally, this method was effective in recognizing and mapping of the hydrothermal alterations.
Sh Fatahi; A.A Calagari; A Abedini; H Bagheri
Abstract
Chahreeseh bentonite deposit is located at ~55 km northeast of Isfahan, structural zone of Central Iran. This deposit has layered and massive form and includes six discrete outcrops. The field observations showed that the ores are genetically related to Oligo-Miocene tuff breccia. The mineralogical studies ...
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Chahreeseh bentonite deposit is located at ~55 km northeast of Isfahan, structural zone of Central Iran. This deposit has layered and massive form and includes six discrete outcrops. The field observations showed that the ores are genetically related to Oligo-Miocene tuff breccia. The mineralogical studies testified to the presence of minerals such as montmorillonite, saponite, beidellite, cristobalite, anorthite, calcite, dolomite, albite, vermiculite, actinolite, pyrophyllite, quartz, sanidine nontronite, orthoclase, microcline, tridymite, and hematite in rock-forming quantities in the bentonitic samples. Based on the minerals chemistry considerations, the Chahreeseh bentonite deposit can be classified as the Wyoming type. The results of mass change calculations (with assumption of Hf as low-mobile index element) show that progression of bentonitization process at Chahreeseh was accompanied by depletion of elements like Al, Fe, K, Ti, Mn, P, Ba, Co, Zn, Cs, Rb, Y, Zr, Ni, Sr, and Cu, enrichment of U, and leaching-fixation of elements such as Na, Mg, Ca, and Si. The geochemical interpretations revealed that variations of Eu negative anomaly (0.27-0.90) and weak negative to weak positive anomalies of Ce (0.97-1.22) at Chahreeseh have been controlled by the degree of feldspar alteration and changes in the rate of oxidation potential of the environment, respectively. By considering the results obtained from field relations, mineralogy and geochemistry, it seems factors such as physico-chemical conditions of alteration environment, absorption mechanism, difference in degree of alteration intensity of parent materials, the degree of access to fluoride, chloride, and sulfate ligands, incorporation in crystal structure, ionic exchange, physical concentration, and the presence in resistant mineral phases played significant roles in distribution and concentration of elements in this deposit, respectively.
M.R Hosseinzadeh; M Moayyed; S Maghfouri; S Alipour; B Hajalilou
Abstract
The study area is located in Arasbaran Metallogenic Zone. The rocks of the Baloojeh region includes of Oligo-Miocene quartz-diorite porphyry, gabbro-diorite, quartz-monzonite and granodiorite. The quartz diorite is the main host rock of porphyry type Cu-Mo mineralization in the Baloojeh deposit, but ...
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The study area is located in Arasbaran Metallogenic Zone. The rocks of the Baloojeh region includes of Oligo-Miocene quartz-diorite porphyry, gabbro-diorite, quartz-monzonite and granodiorite. The quartz diorite is the main host rock of porphyry type Cu-Mo mineralization in the Baloojeh deposit, but also in the other intrusive porphyries, copper mineralization can be seen. Much of the mineralization in the Baloojeh deposit is dispersive and vein- veinlet type. Based on the structure, mineralogy and texture, the Baloojeh vein- veinlets can be divided into four different groups. These veins - veinlets contains sulfide (pyrite, molybdenite, chalcopyrite, boehrnite, galena, and sphalerite), hydroxide and oxide (magnetite, hematite and goethite) and carbonate (malachite and azurite) minerals. Similar to other Cu- Mo porphyry deposits, the Baloojeh deposit contains of potassic, phyllic, argillic and propylitic alterations. The parent magma of intrusives has calk-alkaline to shoshonitic character that implaced in a post-collisional magmatic arc. The fluid inclusion study has been done on the different groups of veinlets. These studies suggest high temperature (221- 381 C°) and high salinity (5- 45 % NaCl) hydrothermal fluid and the occurrence of boiling phenomena in the ore- forming hydrothermal fluids of the Bloojeh deposit.
T Nabaei; A Khakzad; M Hoseini; S.R Mehrnia
Abstract
The study area is a portion of Urmia-Bazman Magmatic Belt in the Central Iran Structural Zone that located in the south of Boein-Zahra city (Qazvin province). In this area, volcanic and pyroclastic rocks incised by a plutonic body and around and within this pluton, a large extensive alteration occurred. ...
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The study area is a portion of Urmia-Bazman Magmatic Belt in the Central Iran Structural Zone that located in the south of Boein-Zahra city (Qazvin province). In this area, volcanic and pyroclastic rocks incised by a plutonic body and around and within this pluton, a large extensive alteration occurred. In this study, Landsat 7 data (ETM+) employed and general alteration trend in the area was mapped by conventional methods of Color Composite (RGB), Band Rationing and specially Principal Components Analysis (PCA). All of the three methods are found to be effective for obtaining generalized information about the alteration of the image area. Principal Components Analysis (PCA) and especially Selective Principal Components Analysis (Crosta technique) found to be the best effective method in delineating the borders of clay and iron oxide altered areas. In the high altered wall rocks, mineralogical analysis results (XRD method) indicated two forms of vertical and horizontal zoning. In this case, in vertical zoning in order from down to up, advanced argillic, alunitic and silicified zones and in horizontal zoning from fault surface toward wallrocks, advanced argillic and propylitic zones were distinguished. The mineralogical composition of zones and form of zoning indicates that this type of alteration is "acid sulfate". The study of fluid inclusion of quartz crystals in silicic veins, indicated that liquid and vapor phases (LV) are present and study of them resulted in calculation of salinity percentages between 16.8 to 19.2 (NaCl wt%) and homogenization temperatures between 204oC to 280oC.
M Akhyani; M Kharqani; M Rahimi; F Sereshki
Abstract
The Torud - Chah Shirin volcanic-plutonic complex is located in the western part of Sabzevar Metallogenic Belt and in the south of Moaleman city in the Semnan province. The presence of several mineral occurrences, especially base metal veins of epithermal origin has increased the economic importance ...
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The Torud - Chah Shirin volcanic-plutonic complex is located in the western part of Sabzevar Metallogenic Belt and in the south of Moaleman city in the Semnan province. The presence of several mineral occurrences, especially base metal veins of epithermal origin has increased the economic importance of the magmatic complex for geological studies. The intrusion of igneous acidic to intermediate bodies in the volcanic rocks of the area has caused different alternation and mineralization in some parts of the area. In this research, various images processing methods such as false color composites (FCC), band ratios (BR) and spectral angle mapping (SAM) were performed on ASTER L1B VNIR+SWIR dataset, for discrimination of alteration zones in the Torud-Chah shirin magmatic arc. Alteration minerals like kaolinite, illite alunite, pyrophyllite, sericite, chlorite, epidote and calcite, which are associated with argillic, advanced argillic, phyllic and prophyllitic zones were recognized by processing aster dataset and highlighted altered area throughout the range. According to the field studies and XRD analysis, accuracy the results of spectral angle mapping and Band Ratio Logical Operator Algorithms evaluated by confusion matrix and kappa coefficient. Accuracy assessment shows an overall accuracy of 72% and 68% and a kappa coefficient of 0.627 and 0.6 respectively for spectral angle mapping and Band Ratio Logical Operator Algorithms for enhancing argillic and phyllic alteration zones in the study area. Therefore, the results show spectral angle mapping method achieved better results in compared to Band Ratio Logical Operator Algorithms.
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.
D Refahi; A Khakzad; N Nezafati; Kh Bahar Firozi; A Bayatani
Abstract
Development of advance tools in remote sensing and airborne geophysics during recent decades shows this industry importance. In this paper, aster sensor imagery (Advanced Space born Thermal – Radiometer) and airborne geophysics employed in order to zoning alteration area, mineralization system ...
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Development of advance tools in remote sensing and airborne geophysics during recent decades shows this industry importance. In this paper, aster sensor imagery (Advanced Space born Thermal – Radiometer) and airborne geophysics employed in order to zoning alteration area, mineralization system analysis and prospecting in 1:25000 Oghlansar sheet, which is situated in north of Sarab City in East Azerbaijan province. The area is located in structural zone of theEastern Alborz-Azerbaijan. The lithology of area contains Eocene-Neogene magmatic-volcanic complex such as andesite, rhyodacite, rhyolite, and granodiorite associated with pyroclastics such as tuffs, volcanic breccia and lava flows. In this investigation, we applied different methods of spectral analysis and normal classification such as SAM (Spectral Angel mapping), MF (Match Filtering) using ASTER images. Furthermore, spectral analysis methods on airborne geophysics data were engaged in order to extract shallow bodies and recognition of faults. ASTER imagery process and airborne geophysics data led to primary potential mineral map of the area. For credibility of results, 200 samples were taken and analyzed by XRD, XRF and ICP methods. Consequently, 190 samples (95%) confirmed the results of remote sensing and airborne geophysics processes. Conclusions of this research revealed that applying concurrency both the remote sensing and airborne geophysics data could be led to improve the precision of the results.
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.
S Soltaninejad; B Shafiei
Abstract
The Now-Chun deposit, in the Kerman porphyry copper belt, with proved reserve of 268 Mt ore grading 0.034% Mo (100 ppm cut off) and 62 Mt ore grading 0.43% Cu (0.25 cut off), is the first known occurrence of Mo-rich,relatively Cu-poor porphyry mineralization in Iran which is studied from the mineralogical, ...
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The Now-Chun deposit, in the Kerman porphyry copper belt, with proved reserve of 268 Mt ore grading 0.034% Mo (100 ppm cut off) and 62 Mt ore grading 0.43% Cu (0.25 cut off), is the first known occurrence of Mo-rich,relatively Cu-poor porphyry mineralization in Iran which is studied from the mineralogical, l, and genetic point of view. The alteration and mineralization of the Now-Chun deposit is related to the highly differentiated porphyritic stock (rhyodacite) belonging to the Oligo-Miocene Mamzar batholith. Based on the present study, the main part of Mo and Cu mineralization in the Now-Chun deposit occurred more in the form of cross-cutting veinlets (stockwork) and less as dissemination type. The presence of molybdenite with/without chalcopyrite association in quartz-anhydrite-orthoclase-biotite potassic veinlets and chalcopyrite occurrence in primary quartz-magnetite veinlets is indicative of the priority of part of the Cu mineralization respect to the Mo during the primary stage of mineralization. The initial mineralization of Mo in the form of molybdenite occurred in quartz-anhydrite-orthoclase-biotite-pyrite-chalcopyrite. The weak correlation between Mo and Cu in the potassic alteration zone (r= -0.2) especially in the high grade ores indicates the difference between the enrichment conditions of both elements in responsible hydrothermal fluids for this alteration and mineralization zone. The presence of thick quartz-pyrite-chalcopyrite veinlets with sericitic halo and quartz-molybdenite without alteration halo either as independent or as intruded within early veinlets (quartz-molybdenite-anhydrite-orthoclase-biotite) have been associated with increasing of Mo and Cu grades in moderately phyllic alteration zone (sericitic and silicified rocks). The positive correlation between Mo and Cu in moderate phyllic zone (r≥ 0.0 to +0.5) which affected potassic ores indicates the similar behavior of both Mo and Cu during formation and evolution of the hydrothermal solution, which is responsible for the alteration and mineralization in the phyllic zone. This study revealed that the main concentration of Mo occurred in deep parts (potassic zone) of the deposit; whereas, Cu is associated with the shallow parts, especially with moderate phyllic zone which affected the potassic zone. As a result, the high grade Mo ores are not Cu-rich and vice versa. The present study indicated that the Now-Chun deposit in comparison with the Sar Cheshmeh deposit (Cu-Mo porphyry) is categorized within the Mo-Cu porphyry deposits. This sub-group of porphyry Cu and Mo deposit is attributed to the function of the Mo-rich and relatively Cu-poor hydrothermal fluids. The more differentiated composition of the ore-hosting porphyry in the Now-Chun deposit (rhyodacite) in comparison with the Sar Cheshmeh porphyry stock (granodiorite-quartzmonzonite), which indicates the late water saturation in its parent magma, was probably the factor of generating such fluids that could segregate the significant proportion of Mo in respect to Cu from the residual melts into H2O, alkalies and silica-enriched fluid phase which ultimately resulted in forming the Mo-Cu porphyry deposit.
Kh. Ebrahimi; p. Roohbakhsh; S. M. Homam; H. Abbasnia
Abstract
Dahaneh Qaleh exploration prospect is located about 300 km southwest of Mashhad and 50 km northwest of Bardeskan. The exploration prospect is also a part of Taknar massive sulfide mineralization zone and lithology of the area consists of chlorite sericite schist, biotite sericite schist and sericite ...
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Dahaneh Qaleh exploration prospect is located about 300 km southwest of Mashhad and 50 km northwest of Bardeskan. The exploration prospect is also a part of Taknar massive sulfide mineralization zone and lithology of the area consists of chlorite sericite schist, biotite sericite schist and sericite schist with metamorphosed basic and intermediate igneous rocks in the type range from meta-gabbro diorite to meta-diorite that they belong to Taknar Formation.Taknar Formation was intrusived by low grade metamorphosed intermediate subvolcanic intrusive rocks with porphyry texture in the type range of meta-hornblende-quartz monzonite porphyry, meta-hornblende-quartz monzodiorite porphyry, meta-hornblende monzodiorite porphyry, meta-quartz monzonite porphyry and meta-hornblende-quartz monzosyenite porphyry. All of the geological unites are affected by moderate to severe alteration and sulfide minerals including pyrite, were transformed to secondary iron oxides due to oxidation. Before the field investigation, ETM+ and ASTER sensors data were processed with "color composition of band ratios", "standard and selective principal component analysis" methods and finally "spectral angle mapping" as a successful method for more accurate separation of altered minerals that introduced Hematitic, Chloritic, Epidotic, Sericitic and Silicification alteration zones in the study area. Accuracy of the processes were proved by the following field, petrography and mineralography studies.
M. Sakhdari; M. Yazdi; M. Behzadi
Abstract
The Shanegh area is located in central part of Sanandag-Sirjan zone, 28km southeast of Delijan. Rock units exposing in the area consists of sedimentary (carbonate, sandstone, siltstone) volcano- sedimentary (andesite to andesitic tuff, tuff) and intrusive host rocks. The volcano- sedimentary units thought ...
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The Shanegh area is located in central part of Sanandag-Sirjan zone, 28km southeast of Delijan. Rock units exposing in the area consists of sedimentary (carbonate, sandstone, siltstone) volcano- sedimentary (andesite to andesitic tuff, tuff) and intrusive host rocks. The volcano- sedimentary units thought to be of Eocene to Quaternary ages which have been intruded by plutonic units. The main host rocks are monzonite, quartz monzonite, andesite and diorite. The host rocks have been altered by pervasive hydrothermal fluids. The alterations are sericitization, kaolinitization, carbonatization and silicification. The host rocks are characterized by fault or shear zones, vein systems, stockwork and dyke mineralization. Ore mineral assemblages are pyrite, chalcopyrite, Fe-oxide and Fe-hydroxides. We did not find gold minerals in our microscopic studies but the gold has been found in the lithogeochemical exploration. The results show that maximum grade of gold in some veins is about 2760 ppb and the mean grade of gold about 80 ppb. Comparing shanegh area main characteristics with epithermal gold deposits, shanegh area has the most similarities with epithermal gold mineralization; therefore, it is considered to be of this type.
