Economic Geology
Morteza Delavari; Amir Ali Tabakh Shabani; Samaneh Ghanbari
Abstract
The Oligocene dacitic volcanic rocks display widespread exposures in south of Julfa (eastern Azerbaijan). They generally show porphyritic to hyalo-porphyritic textures with major minerals of plagioclase, amphibole, quartz and biotite. Electron probe micro analyzer (EPMA) data indicates oscillatory zoning ...
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The Oligocene dacitic volcanic rocks display widespread exposures in south of Julfa (eastern Azerbaijan). They generally show porphyritic to hyalo-porphyritic textures with major minerals of plagioclase, amphibole, quartz and biotite. Electron probe micro analyzer (EPMA) data indicates oscillatory zoning and chemical variation of amphiboles (pargasite and edenite). The plagioclase crystals are, chemically, andesine (An= 29-51%) which mostly display oscillatory zoning. Based on geobarometric calculations, plagioclase displays pressures of 5 to 8 kb and amphiboles demonstrate different pressure ranges of 1.5 to 3 and 5 to 9 kb. Moreover, geothermometric calculations of plagioclase and amphibole provide temperatures of 1020-1050 and 850-900 °C, respectively. On the basis of geobarometric results, crystallization and growth of the minerals took place in magmatic chambers of different levels. Some of the amphiboles nucleated in lower continental crust and subsequently grown during magma ascent in middle crust whereas some others crystallized in the upper continental crust. Therefore, existence of minerals of different levels inside the studied rocks could be related to magma mixing in shallow magma chambers.
Economic Geology
nasrin khajehmohammadlou; Ali Asghar Calagari; Kamal Siahcheshm; Ali Abedini
Abstract
The Aghbolagh iron-copper skarn is located in ~21 km north of Oshnavieh, southwest of West-Azarbaidjan province. The intrusion of Cretaceous granitic body into the Cambrian Barut, Zagun, and Lalun Formations (carbonate, shale, and sandstone) was accompanied by development of calcic-type skarn, hornfels, ...
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The Aghbolagh iron-copper skarn is located in ~21 km north of Oshnavieh, southwest of West-Azarbaidjan province. The intrusion of Cretaceous granitic body into the Cambrian Barut, Zagun, and Lalun Formations (carbonate, shale, and sandstone) was accompanied by development of calcic-type skarn, hornfels, and marble in the study area. The garnets of the Aghbolagh skarn belong to solid solution series of grossularite-andradite in which andradite is the dominant phase (>80%). These garnets are isotropic and lack zonation. The pattern of REE distribution in these garnets shows the enrichment of LREE relative to HREE and also the occurrence of negative anomalies of Eu/Eu* and Ce/Ce*. The comparison of the distribution pattern of REE in garnets with those in igneous (granite and monzonite) and sedimentary (carbonates and sandstones) rocks demonstrates that the REE in garnets were derived mainly from the igneous rocks rather than the sedimentary units. The increase in Pr/Yb ratios in parallel with increase in the ƩREE is indicative of the magmatic origin of the ore-forming fluids in the Aghbolagh skarn. However, the lack of sensible variations between Ce/CE* and ƩREE values indicate that the meteoric waters might have also played a part in skarn-forming fluids at Aghbolagh.
Economic Geology
Mohammad Jafar Kupayi; Ebrahim Rastad; Saeed Madanipour; Sajjad Maghfouri
Abstract
Cretaceous sedimentary sequence in the Yazdan area is consisting of four rock units as, from the old to the new, clastic-carbonate (Kc), carbonate (Kl), Shale and marl (Km) sequences, and Sandy limestone and sandstone (Kls). The Kls unit is host of ore mineralization in the study area and formed from ...
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Cretaceous sedimentary sequence in the Yazdan area is consisting of four rock units as, from the old to the new, clastic-carbonate (Kc), carbonate (Kl), Shale and marl (Km) sequences, and Sandy limestone and sandstone (Kls). The Kls unit is host of ore mineralization in the study area and formed from four members. Ore mineralization in the Yazdan Deposit has occurred as a stratiform horizon in the sandstone units of the third member. Texture and structures studies, shown three ore facies with elemental zonation in the Yazdan Deposit. These ore facies includes, stringer zone, massive ore facies and the bedded ore facies. This ore facies formed from laminated and layered sulfide and sulfate minerals. Fluid inclusions studies represents 255-136 ° C of homogeneity temperature with an average temperature of 189 ° C. Also, the salinity of fluid inclusions was calculated to be between 14.6-6% NaCl (on average, 9.5% NaCl). Geological evidence, host rocks type, texture and structures, existence of ore facies with elemental zoning as well as fluid inclusion investigations indicate the Yazdan Deposit has most similarity with Sedex-type deposit.
Economic Geology
Mohammad Boomeri; Somayeh Naruyi; Mohammadreza Ghodsi
Abstract
The Chah Sorbi area is located in the Sistan suture zone. The geology in the Chah Sorbi, from old to young, are flysch type rocks, Zahedan granitoid, subvolcanic granodiorite porphyry, dioritic to granodioritic dikes and recent deposits. The Pb mineralization in the study area occurs as thin and short ...
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The Chah Sorbi area is located in the Sistan suture zone. The geology in the Chah Sorbi, from old to young, are flysch type rocks, Zahedan granitoid, subvolcanic granodiorite porphyry, dioritic to granodioritic dikes and recent deposits. The Pb mineralization in the study area occurs as thin and short galena-bearing veins associated with pyrite, quartz, calcite, goethite and limonite. The host rocks are flysch and the subvolcanics that are undergone phyllic and argillic alteration. Propylitic alteration occurs in most dikes in the area and is characterized by chlorite, calcite and epidote. In northeast part of the area, the subvolcanic rocks were intruded by quartz stockworks and was strongly altered. The most intensive and extensive alteration with these rocks is phyllic alteration that is characterized by pyrite, quartz and sericite. Cu mineralization in the stock is characterized by presence of Cu-carbonate and –sulfides. Galena-bearing veins are probably epithermal type in the Chah Sorbi area that is situated in margin of a porphyry Cu system. Major and minor elements were measured in 7 least altered samples from intrusive rocks. The igneous rocks in the study area are metaluminous that are formed from a calc-alkaline magma in a continental margin volcanic arc setting.
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.
Economic Geology
Sanaz Ahmadi; Mohammad Ali Salehi; H Jamali
Abstract
The Hassan Abad Zn-Pb deposits is located in the northeast of Isfahan, Central Iran zone. The host rock of this mineralization is the dolomite of Middle Triassic Shotori Formation. Mineralization included galena, sphalerite, sulfosalts, pyrite and barite which associated with dolomitization. Based on ...
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The Hassan Abad Zn-Pb deposits is located in the northeast of Isfahan, Central Iran zone. The host rock of this mineralization is the dolomite of Middle Triassic Shotori Formation. Mineralization included galena, sphalerite, sulfosalts, pyrite and barite which associated with dolomitization. Based on petrographic studies six types of dolomites (in terms of shape and size of the crystals, the distribution of crystal size and shape of the border crystal) has been identified, that including very fine, medium, coarsely crystalline dolomite, Saddle dolomites and filling pore spaces and veins. The first and second type of dolomites were formed as synsedimentary or diagenetic dolomite with sabkha origin. The third type of dolomite in the late stages of diagenesis was formed in shallow burial conditions due to recrystallization of small crystalline dolomite. Coarse-grained and saddle dolomites have been created under the conditions of deep burial and as hydrothermal dolomites and are related to mineralization. Move over, the origin of magnesium for fine crystalline dolomites were seawater, and for coarse crystalline dolomites are probably the brine fluids of the compacted Sorkh Shale Formation and hydrothermal fluid.
Economic Geology
Ali Rajabzadeh; Hossein Kouhestani; Mir Ali Asghar Mokhtari; Afshin Zohdi
Abstract
In this study, petrography and major and minor elements geochemical data are presented for sandstone layers of the Upper Red Formation (URF) in the Chehrabad Pb-Zn deposit (NW Zanjan) to investigate sandstone composition, tectonic setting and their source rock. In this area, URF has 980 m thickness and ...
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In this study, petrography and major and minor elements geochemical data are presented for sandstone layers of the Upper Red Formation (URF) in the Chehrabad Pb-Zn deposit (NW Zanjan) to investigate sandstone composition, tectonic setting and their source rock. In this area, URF has 980 m thickness and is conformably overlies the Qom Formation limestones. Based on the microscopic studies, these sandstones mainly composed of fine- to coarse-grained clastic fragments including sedimentary and metamorphic rock fragments (45 %), quartz (38 %) and feldspar (17 %). Based on petrographic studies, these sandstones are feldspathic litharenite and litharenite (mainly chertarenite). Based on the main components and major and minor elements geochemical data, the tectonic setting of these sandstones is an active continental margins and foreland basins. These data represent an intermediate to felsic source rock for these sandstones which was affected by the semi-humid to semi-arid climate and a low chemical weathering.
Economic Geology
Z. Zandi; A. R. Jafari rad; A. Gourabjeripour; M. Lotfi
Abstract
The Saheb Fe-Cu skarn deposit is located in the Sanandaj-Sirjan metamorphic belt, SE Saqqez, western Iran and has been formed along the contact between the Oligo-Miocene aged Saheb granitoid and the Permian aged impure calcareous rocks and includes endoskarn and exoskarn. Exoskarn is widely developed ...
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The Saheb Fe-Cu skarn deposit is located in the Sanandaj-Sirjan metamorphic belt, SE Saqqez, western Iran and has been formed along the contact between the Oligo-Miocene aged Saheb granitoid and the Permian aged impure calcareous rocks and includes endoskarn and exoskarn. Exoskarn is widely developed and include garnet and epidote skarn zones. The majority of mineralized zones are concentrated in garnet skarn. The relatively oxidizing mineralogical assemblage of the Saheb skarn includes garnet (andradite-grossular), pyroxene (diopside-hedenbergite), magnetite and hematite. Magnetite is the main and abundant ore mineral throughout the ore deposit. Based on field evidences and microscopic studies of skarn zone samples, two stages of prograde and retrograde alteration are distinguishable. According to the results of sample analysis of Saheb skarn productive intrusive body by XRF and ICP-MS techniques, the combination of this body is chiefly granite to granodiorite-diorite and belong to the I-type granitoids, metaluminous and K-rich calc-alkaline series. The Saheb granitoid is related to the VAG (Volcanic Arc Granite) tectonic setting.
Economic Geology
Raziyeh Mahabady; Farajollah Fardoost
Abstract
Abgareh copper deposit located in 140 km southwest of shahrood and part of a volcanic-sedimentary Torud-Chah shirin belt that has facies in the northern edge Structural-sedimentary zones of Central Iran. Field and petrographical studies, deposit area, consist of andesite, basaltic andesite and basalt ...
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Abgareh copper deposit located in 140 km southwest of shahrood and part of a volcanic-sedimentary Torud-Chah shirin belt that has facies in the northern edge Structural-sedimentary zones of Central Iran. Field and petrographical studies, deposit area, consist of andesite, basaltic andesite and basalt and contains less includes tuffit crystal that indicate middle–upper Eocene with with argillitic, sericitic, silicic, carbonatic, chloritic and iron oxides alterations. According to the field observations and mineralogical studies, the mineralization in the region was carried out in two stages: hypogene and supergene and weathering. Hypogen zone minerals are generally pyrite, chalcopyrite and bornite. Because of existence in oxidizing-supergene environment , nearly almost Cu-bearing minerals of the main stage of mineralization have been replaced by secondary Cu minerals such as chalcocite, covellite, malachite and chrysocolla. Fluid inclusion data shows in the temperature range from 145 to 217 °C and salinity between 3.73 and 9.84 Wt%NaCl and depths less than 390 m. The host rocks, ore mineralogy, ore structures and textures, and fluid inclusions characteristics and comparison with similar epithelial deposits indicate that the Abgareh vein system is formed in a low-sulfidation epitermal environment.
Economic Geology
Maryam Kiaeshkevarian; Ali Asghar Calagari; Ali Abedini; GholamHossein Shamanian
Abstract
The Gheshlagh bauxitic deposit is located in ~110 km southeast of Gorgan city. Mineralogical studies indicated the presence of minerals such as boehmite, diaspore, kaolinite, hematite, goethite, anatase, rutile, chamosite, calcite, moscovite, clinoclar, provskite, quartz, and dolomite. Based on quantitative ...
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The Gheshlagh bauxitic deposit is located in ~110 km southeast of Gorgan city. Mineralogical studies indicated the presence of minerals such as boehmite, diaspore, kaolinite, hematite, goethite, anatase, rutile, chamosite, calcite, moscovite, clinoclar, provskite, quartz, and dolomite. Based on quantitative mineralogy this deposite made up of (1) bauxitic clay, (2) clayey bauxite, (3) bauxitic clayey iron ore and (4) bauxitic iron ore. Calculations of the enrichment factors, with assumption of upper continental crust (UCC) as parent rocks, showed that elements such as Rb, Cs and Ba were depleted during bauxitization processes whereas elements like Y, Cr, Co, Ni, V and HREEs were encountered enrichment.Elements like Sr, Ga, Zr, Hf, Nb, Ta, U, Th and LREEs underwent both leaching and fixation processes during development of the weathered profile. Combination of the results obtained from mineralogical and geochemical investigations showed that factors such as adsorption, scavenging by metallic oxides and hydroxides, fluctuation of underground water level, type and stability of metal-containing complexes, stability of primary bearing minerals, presence in mineral phases resistant to weathering and changes in chemistry of the solutions responsible for weathering played prominent role in distribution and mobilization of elements in the studied bauxitic ores.
Economic Geology
Zahra Akbari; ali yarmohammadi; Iraj rassa
Abstract
The Fe-Pb Ahangaran deposit, hosted by tuffaceous siltstone of the Early Cretaceous sedimentary sequence in the northern part of the Malayer-Esfahan Metallogenic Belt (MEMB), Iran. Ore mineralization occurred as stratiform and a widespread veinlet zone in the upper part of Lower Cretaceous terrigenous ...
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The Fe-Pb Ahangaran deposit, hosted by tuffaceous siltstone of the Early Cretaceous sedimentary sequence in the northern part of the Malayer-Esfahan Metallogenic Belt (MEMB), Iran. Ore mineralization occurred as stratiform and a widespread veinlet zone in the upper part of Lower Cretaceous terrigenous unit (Kc). Four different ore types can be distinguished in deposit include: (1) veinlet (feeder) zone, (2) sulfide-Fe- oxide stratiform ore (3) barite ore and (4) vein ore. Ore minerals in the different ore types are pyrite, siderite, magnetite, galena, barite, chalcopyrite and tetrahedrite and rare minerals are pyrrhotite, arsenopyrite, and freibergiteCarbonatization and silicification are the main hydrothermal alterations in this deposit. The orebodies in the Ahangaran deposit have been replaced by iron oxide minerals in supergene process and have been formed a thick gossan zone. The textural and mineralogical data provide evidence of three stages of mineralization (Early, main and late stage) in Ahangaran deposit. According to evidences such as tectonic setting, type of host rock, geometry of deposit, sulfide-Fe oxide ore types, textures and structures indicate that the Ahangaran deposit is compatible with a sub-seafloor replacement mineralization that has been suggested for some Sedex deposits.
Economic Geology
Maryam Honarmand; Ghasem Nabatian; Mahtab Aflaki; Mohammad Ebrahimi
Abstract
Geology, geochronology and tectonic setting of the Moghanlou mylonite gneiss and granite bodies, west of Zanjan Abstract The Moghanlou mylonite gneiss and granite assemblage is located in the west of Zanjan forming a part of the magmatic-metamorphic association in the Takab area. The Moghanlou assemblage ...
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Geology, geochronology and tectonic setting of the Moghanlou mylonite gneiss and granite bodies, west of Zanjan Abstract The Moghanlou mylonite gneiss and granite assemblage is located in the west of Zanjan forming a part of the magmatic-metamorphic association in the Takab area. The Moghanlou assemblage comprises of leucogranite and biotite granite intrusions which have surrounded the gneiss body. The zircon U-Pb dating shows the ages of 563±6.5 Ma for the mylonite gneiss, 576±13 Ma for the biotite granite and 559±6 Ma for the leucogranite intrusions. Moreover, the samples from the Moghanlou assemblage display high-K calc-alkaline and slightly peraluminous affinities, except those from the leucogranite which are low potassium samples due to the sodic alteration and albitization of the K-feldspars. The trace element patterns suggest LILE and LREE enrichment and HFSE and HREE depletion as well negative anomaly of Nb, Ta and Ti. In general, the geochemical features of the Moghanlou intrusions are comparable with the melts formed from crustal partial melting in magmatic arc environment. The Moghanlou assemblage is analogues to other Late Neoproterozoic-Early Cambrian igneous and metamorphic associations in Iran and Turkey which are related to the igneous activity along the Cadomian magmatic arc, in north of Gondwana supercontinent.
Economic Geology
Maryam Javidi Moghaddam; M.H Karimpour; Azadeh Malekzadeh Shafaroudi
Abstract
The Rashidi area, which comprises a part of the north Khur in eastern Iran is located at 120 km northwest of Birjand city. Preliminary prospecting in the area using the image processing of ASTER data by Spectral Angle Mapper (SAM) algorithm resulted in the identification of propylitic and argillic alteration ...
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The Rashidi area, which comprises a part of the north Khur in eastern Iran is located at 120 km northwest of Birjand city. Preliminary prospecting in the area using the image processing of ASTER data by Spectral Angle Mapper (SAM) algorithm resulted in the identification of propylitic and argillic alteration zones together with iron oxy-hydroxide minerals. The area consist of outcrops of Eocene pyroclastic rocks ranging from andesitic to rhyolitic in composition, intruded by diorite porphyry dikes. Vein mineralization in the area was mainly occurred along a fracture system hosted by andesitic tuff breccia unit. Vein copper mineralization was formed during two stages including the: (1) quartz-pyrite-chalcocite-tennantite assemblage, and (2) quartz-chalcocite-pyrite-sphalerite assemblage. The values of δ18O for quartz in the first and second stages of vein mineralization was 19.26 and 14.94 and the amount of δ18O water in equilibrium with quartz was 10.96 and 4.94 respectively that shows a magmatic origin and mixing with meteoric water in the second stage. Based on geology, vein geometry, fluid inclusion, and stable isotope geochemistry, the Rashidi Cu deposit can be classified as vein-type copper deposits, which has been formed along fault zones.
Economic Geology
mahboobeh yaghobi; sasan bagheri
Abstract
In Eastern Iran, the Eocene platform deposits of northwest of Birjand, are a suitable case; because a thin thrust sheet of Eocene carbonate have had the possibility to slide and fold upon an upper cretaceous plastic footwall. Moreover, this carbonate sheet entirely covered the structural arc, conduct ...
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In Eastern Iran, the Eocene platform deposits of northwest of Birjand, are a suitable case; because a thin thrust sheet of Eocene carbonate have had the possibility to slide and fold upon an upper cretaceous plastic footwall. Moreover, this carbonate sheet entirely covered the structural arc, conduct us to recognize the origin of the bending. Achieving to this goal, we passed the structural arc along the six cross sections; four sections along radial trends and two transversal sections parallel to the inflection line. In these measurements, folds and thrust faults were defined as far as possible. The cross sections have been restored by the "Move Softwear". The amount of shortening along the radial sections were measured respectively from the east to the west are the 30-40% along A, 25-35% along B, 35-45% along C, and 15-25% along D; and along the transversal section are respectively from the south to the north about the 35-55% along E and 25-35% along F. The shortening amount in the platform carbonate at two-facing ends of the structural arc as well as the one along the inflection line are the greatest. The pattern of shortening in the arc seems to follow a buckle folding mechanism.
Economic Geology
faraj fardoost; Akbar Abdollahi Hydarbaghi; Solmaz Baluchi
Abstract
The Robaei Iron deposit is located in 96km south of Damghan. Host rocks of deposit are Late Cretaceous limestones (part I) and Eocene volcano- sedimentary rocks including sandy tuff (part II.( The alterations include chloritization, epidotization, argillation, silicification, carbonatization and hematitization. ...
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The Robaei Iron deposit is located in 96km south of Damghan. Host rocks of deposit are Late Cretaceous limestones (part I) and Eocene volcano- sedimentary rocks including sandy tuff (part II.( The alterations include chloritization, epidotization, argillation, silicification, carbonatization and hematitization. Minerals forming can be divided into three groups; iron minerals (hematite, magnetite, pyrite, pyrrotite goethite and limonite), copper- minerals (chalcopyrite, chalcocite, covellite and malachite) and gangue minerals (calcite, dolomite, quartz, garnet, epidote and chlorite). The structure and textures of ore minerals are massive, vein- veinlet, open space filling and disseminated. In part I, the metals grade of Fet is about 60%, Cu 0.7 % and Au 2.7 ppm and in the part II, the Fet are variables between 5.88 to 82.91% (average 31.2%), Cu between 275 to 20761 ppm and Au 0.89 ppm. Fluid inclusion studies were carried out on quartz mineral from the part II that homogenization temperature is frequency variables between 200 to 249°C with salinity of 2-4% wt. %NaCl. Based on the results of this investigation, part I has similarities with calcic skarn of low temperature and part II showed more similarities with iron oxide- copper- gold (IOCG) deposits.
Economic Geology
Amir Pakizeh; Fardin mousivand; Abdorrahman Rajabi; Sajjad Maghfouri
Abstract
The Nohkuhi copper deposit located at 40 Km Northwest of Kerman, occurred in the Central Iran structural zone (Bafq- Posht-e- Badam block), within Late Precambrian-Early Cambrian volcano-sedimentary sequences. Host sequence of mineralization consists of dominantly black shale, sandstone and dacitic lava ...
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The Nohkuhi copper deposit located at 40 Km Northwest of Kerman, occurred in the Central Iran structural zone (Bafq- Posht-e- Badam block), within Late Precambrian-Early Cambrian volcano-sedimentary sequences. Host sequence of mineralization consists of dominantly black shale, sandstone and dacitic lava of Rizu Series. Mineralization occurred as stratabound (vein-veinlets) and stratiform (bedded) in the three copper- and two iron-manganese horizons. The mineralization in the Nohkuhi area involves four ore facieses including stringer, vent complex, bedded, and hydrothermal-exhalative banded iron and manganese-rich sediments. This mineralization contains primary pyrite, chalcopyrite, sphalerite, hematite and pyrolusite. Wallrock alterations are dominated by chloritic and carbonatic-sericitic- silicic. Metal zonation was observed in the deposit. Based on characteristics of mineralization, such as tectonic setting, host rocks, ore textures and structures, mineralogy, metal and alteration zonation, and comparison with main characters of the volcanogenic massive sulfide (VMS) deposits, the mineralization shows most similarities with the siliciclastic felsic or Bathurst- type deposits.
Economic Geology
Sahar Tarabi; Mohamad Hashem Emami; Sourosh Modaberi; Seyed Jamal Shaykh Zakariaee
Abstract
Momen-abad area, in the southeast of Birjand and the northeast of Sarbisheh, is located in the Sistan-Zemestan zone. Based on the field studies, petrography, geochemical (XRF) and X-ray diffraction (XRD) in two volcanic sequences, the alteration conditions in the area have been investigated. According ...
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Momen-abad area, in the southeast of Birjand and the northeast of Sarbisheh, is located in the Sistan-Zemestan zone. Based on the field studies, petrography, geochemical (XRF) and X-ray diffraction (XRD) in two volcanic sequences, the alteration conditions in the area have been investigated. According to mineralogy and chemical studies, bentonites are sodium-calcium and heterogeneous. Mineralogy findings indicate that smectite minerals, cristobalite and quartz, alkaline feldspars (albite and anorthite and sanidine), gypsum, calcite, hematite, holandite, klinoptiolite, kaolinite, ileite, and halite minerals form bentonites. In the first sequence, the effects of argillic and iron oxide alterations and in the second sequence, the effects of alteration of argillic, carbonate, chlorite, calcite, albite, silicification and iron oxide are found. Altered units which are related to the second sequence in four layers include Rhyolytic perlites of the vein, masses, lenses; white bentonites and green; Rhyodacite and dacite with the effects of alteration of devitrification, and the alteration of perlite to bentonite, advanced argillic and silicification. In addition, the composition textures of lava-pyroclastic, devitrification and the alteration of perlite to bentonite due to diagenetic alteration are found out. Glass argillization and feldspars in volcanic units, and the alteration of plagioclase to albite + sericit, biotite to chlorite, stone to quartz, calcite, zeolite and chlorite in perlites, iron oxide veins and red unit are found out in the sequences. Moreover, the change color of bentonite in the region related to alteration hydrothermal, and the presence of fluids and iron-magnesium-rich solutions are obvious in these sequences.
Economic Geology
Hasan Feizi; Sohelia Aslani; Farhang Aliyari; Abbas Bahroudi; Abdolhamid Sartipi
Abstract
The Khanik-Ghazan Titanium ore deposit is located at 82 km northwest of Urmia, northern Sanandaj-Sirjan zone. The main objective of this research is to identify potentially mineralized areas and to prepare a mineral prospectivity map in the Khanik-Ghazan deposit applying the Fuzzy Inference System (FIS). ...
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The Khanik-Ghazan Titanium ore deposit is located at 82 km northwest of Urmia, northern Sanandaj-Sirjan zone. The main objective of this research is to identify potentially mineralized areas and to prepare a mineral prospectivity map in the Khanik-Ghazan deposit applying the Fuzzy Inference System (FIS). After preparing the facto maps, the main stages of the investigation comprise the preparation of fuzzy factor maps using the appropriate linguistic variables and proper membership functions, combining factor maps using the fuzzy inference (by creating a fuzzy database of If-OR rules), identification of susceptible areas, and the generation of a potential mineral map using the output closure. In this study, in order to control the accuracy of the data, we tried to apply two new integrated methods including the fuzzy logic and hierarchical analysis processes. The results obtained from these methods was confirmed and complemented by each other and demonstrated highly potential mineralized zones. This statement is validated by several investigation methods including the field surveys and evidence of 80 samples collected from rock outcrops. Based on obtained results and modelling of geophysical data, the central part of the study area was recognized for further exploration using the drillcore subsurface exploration.
Economic Geology
Amir Naderi; Ghasem Nabatian; Maryam Honarmand; Hossein Kouhestani
Abstract
Halab manganese deposit is located in the Sanandaj- sirjan zone, 100 km southwest of Zanjan. The rock units in the study area include Precambrian Kahar and Jangoutaran marble Formations. Manganese mineralization in the Halab area, occurred as veins and massive in the Jangoutaran marble and minor amount ...
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Halab manganese deposit is located in the Sanandaj- sirjan zone, 100 km southwest of Zanjan. The rock units in the study area include Precambrian Kahar and Jangoutaran marble Formations. Manganese mineralization in the Halab area, occurred as veins and massive in the Jangoutaran marble and minor amount in the schist unit. The main important minerals in the Halab manganese mineralization consist of pyrolusite, psilomelane, manganite and goethite, which calcite and quartz occurred as associated gangue minerals. The ore textures include cloform, vein-veinlets, massive, comb, dogtooth, botryoidal, replacement and relict. Actinolite, carbonate and silicic are the main important alterations in this area. Primitive mantle normalized of the rare earth elements (REE) patterns in the orebody and hydrothermal carbonate samples show that the samples relatively enrichmed in light REE. The analyzed samples show significant negative anomaly in Ce and weak negative anomalies in Eu. Furthermore, the primitive mantle normalized pattern of trace elements in the orebody and hydrothermal carbonate show significant enrichment in Ba, U, La, Pb, Sr and negative anomaly in Rb, Th, Nb, Ce, P, Zr and Ti. The field and microscopic studies as well geochemical evidences suggest that the mineralization formed by hydrothermal fluids. The circulation of meteoric and/or magmatic fluids within the Precambrian units provide the important elements such as Mn, Fe and Ca for mineralization. When the mineralizing fluid contact with reactable rocks, caused the formation of Mn mineralization in the Halab area.
Economic Geology
Rasoul Sepehrirad; Saeid Alirezaei
Abstract
The Gazestan iron-apatite deposit in the Bafq mining district, is hosted in the upper Proterozoic-lower Cambrian volcanic-sedimentary sequence, known as Rizu series, and shallow intrusions. In backscattered electron (BSE) images, the apatite displays irregular light and dark zones with variable compositions. ...
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The Gazestan iron-apatite deposit in the Bafq mining district, is hosted in the upper Proterozoic-lower Cambrian volcanic-sedimentary sequence, known as Rizu series, and shallow intrusions. In backscattered electron (BSE) images, the apatite displays irregular light and dark zones with variable compositions. The dark zones contain inclusions of monazite and xenotime, and are distinguished by depletions in LREE+Y, Na and Cl, and enrichments in Ca and P. Development of reaction rims around apatite crystals, the occurrence of monazite and xenotime as scattered fine grains as well as filling microfractures in the dark zones, and the occurrence of the REE minerals at apatite-magnetite boundary provide evidence for alteration of the original apatite crystals in Gazestan. There is evidence that the apatite crystals formed during original magnetite-apatite ore formation, interacted and reequilibrated with fluids. During a coupled dissolution-reprecipitation process, the original apatite partially reacted with fluids of external origin. This led to leaching/reprecipitation of certain components, in particular the REEs, and development of dark apatite zones with fine, scattered monazite and xenotime grains, as well as the occurrence of fine REE mineral grains across microscopic fractures in apatite, calcite and quartz.
Economic Geology
Mohammad Jabarian; mehrdad karimi; Mohammad Lotfi; kamal noori khankahdani
Abstract
Dehkooye salt dome is located 30 km northeast of Lar in Fars province, Iran. The salt dome occurred in Zagros folded zone where infracambrian thick evaporate strata (Hormoz series) intruded Cenozoic sedimentary rocks. Core of the dome mainly made up of salt and gypsum and overlain by marl, gypsum, limestone, ...
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Dehkooye salt dome is located 30 km northeast of Lar in Fars province, Iran. The salt dome occurred in Zagros folded zone where infracambrian thick evaporate strata (Hormoz series) intruded Cenozoic sedimentary rocks. Core of the dome mainly made up of salt and gypsum and overlain by marl, gypsum, limestone, and dolomitic formations. Besides primary stratiform mineralization, epigenetic iron and copper mineralization occurred mostly within dolomitic lime stone members in the cap rock of the salt dome in Hormoz Formation. Ore mineralogy is simple and includes hematite, minor goethite, and sparse occurrence of magnetite. Chalcopyrite is evident as minor phase. Samples for fluid inclusion studies were collected from sulfide-bearing quartz veins and veinlets. According to homogenization temperature (Th: 172-374 ° C with average 374° C), which in fact represents the boiling point of the irrigation solution, indicate the epithermal to the beginning of hypothermal conditions and the mean of the beginning of the mesothermal. The depth formation of deposit was between 50 to 1500 meters and an average of about 200 meters. The hydrothermal solutions forming the ore deposit, due to their high salinity, have the origin of magmatic brine that have been displaced because of low density and tectonic pressures. This solutions have climbed upwards along faults and fractures and after being mixed with meteoric waters, epigenetic mineralization is created.
Economic Geology
Majid Hafez Darbani; Ali Abedini; Farhang Aliyari; Ali Asghar Calagari
Abstract
The Kuh-Baba iron ore deposit is located in ~70 km south of Hashtroud, East-Azarbaidjan province, NW Iran. The lithologic units cropped out around this deposit include Oligo-Miocene volcanic-sedimentary rocks, Pliocene intrusive rocks, and Pliocene dacitic domes. The principal host rocks for the Fe mineralization ...
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The Kuh-Baba iron ore deposit is located in ~70 km south of Hashtroud, East-Azarbaidjan province, NW Iran. The lithologic units cropped out around this deposit include Oligo-Miocene volcanic-sedimentary rocks, Pliocene intrusive rocks, and Pliocene dacitic domes. The principal host rocks for the Fe mineralization include units of gabbro-norite, pyroxene hornblende gabbro-norite, and monzo-diorite. Remote sensing investigations (using Sentinel satellite images) display the presence of lineaments, NE-SW trending fault structures, and various alteration zones. The dominant hydrothermal alteration in inner parts of the deposit is mainly propylitic (epidote, chlorite, sericite) which gradually changes to argillic outward toward the peripheral parts. Based upon field relations and microscopic examinations, the ores show massive, vein/veinlet, brecciated, and disseminated textures. In the propylitic zone, magnetite is accompanied by epidote and actinolite. The geochemical studies revealed that the FeT content in the diamond drill core samples varies from 3.85 wt% to 63.2 wt%. Ground magnetic survey was conducted in the area and also, the maps of total magnetic field, reduced to pole magnetic, analytic signal, first vertical derivative, and upward continuation were prepared in an attempt to identify the potential deep and shallow subsurface mineralized zones. The obtained results show that two anomalies, one in the north and the other in the central parts of the study area, were recognized which almost correspond with the location of the intrusive bodies.
Economic Geology
iman shojaian; A. Akbarpour; Khalil Baharfirouzi; Majid vanaei
Abstract
The Darreh Rahim Iron deposit occurred in 2km northwest of Ghohroud village, 25 km south of Kashan city, in Ghamsar county suburb, Isfahan province, on Urumyeh-Dokhtar magmatic belt. . Based on the petrography data, the main intrusive body of the district has medium to coarse granular texture and granodiorite ...
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The Darreh Rahim Iron deposit occurred in 2km northwest of Ghohroud village, 25 km south of Kashan city, in Ghamsar county suburb, Isfahan province, on Urumyeh-Dokhtar magmatic belt. . Based on the petrography data, the main intrusive body of the district has medium to coarse granular texture and granodiorite rock composition. Injection of this intrusive body in the Cretaceous age limestone caused the formation of skarn processes and related Iron mineralization. An assemblage of pyroxene, chlorite, garnet, calcite and quartz are the main components of skarn and also gang minerals of the ore. Also all evidences of mineralogy, structure and texture, geochemistry and tectonic setting and Ni/(Cr+Mn)toTi+V andCa+Al+Mn toTi+V diagrams showed a similarity of the DarrehRhim ore deposit to Iron-Copper mineralization.
Economic Geology
yegane khoramtash; farajolah fardoost
Abstract
The Saghari copper deposit is located 120 Km at Southwest of shahrood, within in the eastern part of Toroud-Chahshirin magmatic arc. Mineralization in the Saghari area occured within volcanic and pyroclastic units of Eocene. Based on the field, laboratory investigations and geochemical analysis, the ...
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The Saghari copper deposit is located 120 Km at Southwest of shahrood, within in the eastern part of Toroud-Chahshirin magmatic arc. Mineralization in the Saghari area occured within volcanic and pyroclastic units of Eocene. Based on the field, laboratory investigations and geochemical analysis, the outcropped rocks in the Saghari deposit are andesite, andesite-basalt, basalt, dacite and several exposures of pyroclastic rocks such as tuff and agglomerate. The rocks are high-k, calc-alkaline to a small amount of shoshonitic in nature, and are formed at a magmatic arc setting in a subduction zone. Basic to intermediate dyke bodies intruded Eocene volcanic-pyroclastic sequences. The host rocks have been affected by argillitic, sericitization, chloritzation, carbonatization and oxide-Fe (limonite, hematite and goethite). The textures and structures of mineralization are vein-veinlet, replacement, open space filling and disminated. According to the mineralography studies, main minerals of copper are malachite, chalcocite, covellite, chalcopyrite, chrysocolla and rare native copper. Malachite and chalcosite are the most abundant minerals. Geochemical studies indicate that copper has a relative correlation with silver.also based on studies of fluid inclusion, the depth of the ore, formation temperature and salinity are 100-200 meter, 100-140 °c and 5-15 WtNaCl%. Copper mineralization in the Saghari deposite has similarities in mineralogy, host rock, texture, structure and geometry with manto-type and volcanic red bed copper deposits.
Economic Geology
Fardin mousivand; Fayeq Hashemi; Mehdi Rezaei-Kahkhaei; Amir Pakizeh
Abstract
The Darreh Amrood Pb (Ag) deposit is located in south of Ghohrood, in the Urumieh-Dokhtar magmatic arc (UDMA). Host rockes to the deposit are Middle to Late Eocene grey-green siliceous tuff and crystal lithic tuff. Geometry of orebodies is stratabound, irregular, and semiconcordant to discordant to layering ...
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The Darreh Amrood Pb (Ag) deposit is located in south of Ghohrood, in the Urumieh-Dokhtar magmatic arc (UDMA). Host rockes to the deposit are Middle to Late Eocene grey-green siliceous tuff and crystal lithic tuff. Geometry of orebodies is stratabound, irregular, and semiconcordant to discordant to layering of the host rocks. Ore structures and textures are dominated by semi-massive to brecciated, banded and vein-veinlets. Main primary minerals are galena, pyrite and chalcopyrite, and secondary minerals are dominated by covelline, goethite and hematite. Gangue minerals are epidote, chlorite, sericite, clay minerals, quartz, calcite and barite. Wall rock alterations are dominated by epidote-chlorite and sericitic. The rare earth element (REE) pattern of ores is not similar to that of volcanic rocks in the footwall and hangingwall that is concordant with sub-seafloor replacement process for ore formation. Also Ce showed negative anomaly that can be attributed to Ce in the seawater. Also based on structural, stratigraphic, petrographic, textures, mineralogical, alteration and geochemical studies, it is inferred that the Pb (Ag) mineralization in the Darreh Amrood area occurred as bimodal felsic- or Kuroko-type volcanogenic massive sulfide (VMS) mineralization, and formed as sub-seafloor replacement. It should be noted that the Darreh Amrood deposit is the first recognition of base metal-rich and poor barite VMS mineralization in the UDMA.
