Original Research Paper
Volume 24, Issue 95 , June 2015, Pages 1-1
Original Research Paper
Volume 24, Issue 95 , June 2015, Pages 2-2
Original Research Paper
Volume 24, Issue 95 , June 2015, Pages 3-3
Original Research Paper
M Aghazadeh; Z Badrzadeh; A Castro
Abstract
The studied Roudbar and Abhar plutons are located in the western Alborz zone and Taroum subzone. These intrusive bodies show metaluminous and shoshonitic nature and they cut the Eocene volcanic and sedimentary rocks. In the studied plutons, monzonite and quartz monzonite terms are dominant. According ...
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The studied Roudbar and Abhar plutons are located in the western Alborz zone and Taroum subzone. These intrusive bodies show metaluminous and shoshonitic nature and they cut the Eocene volcanic and sedimentary rocks. In the studied plutons, monzonite and quartz monzonite terms are dominant. According to geochemistry, these plutons were crystallized from non-primary magma, and have been experienced fractional crystallization. In the primary mantle normalized spider diagrams and chondrite normalized REE diagrams, studied samples show clear enrichment in the LREE and LILE and depletion in the HFSE. The primary magma originated from 1-5% partial melting of phlogopite bearing lithospheric mantle with spinel lherzolite composition that metasomatized by subduction agents. According to U-Pb SHRIMP dating, these plutons were intruded during 37.8 to 38.9 Ma in the late Eocene and in a post-collision tectonic setting.
Original Research Paper
M Foudazi; H Sheikhi Karizaki; M Qholipour
Abstract
The outcropped intrusive bodies in NW of Takestan show a combination of granite, granodiorite, tonalite, monzodiorite, quartz syenite, quartz monzodiorite, monzonite, quartz monzonite, and diorite. The granitoids rocks are calc-alkaline, high-K calc-alkaline, shoshonite, and metaluminous in character. ...
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The outcropped intrusive bodies in NW of Takestan show a combination of granite, granodiorite, tonalite, monzodiorite, quartz syenite, quartz monzodiorite, monzonite, quartz monzonite, and diorite. The granitoids rocks are calc-alkaline, high-K calc-alkaline, shoshonite, and metaluminous in character. The shoshonite characteristics of these rocks are caused by deformations created by the effect of penetration of hydrothermal solutions, which also increased some of the mobile elements such as potassium. The tectonic environment of these granitoid bodies are determined based on the geochemistry of main elements as collision (of Late Orogenic) and post collision uplift as well as collision (IAG+CAG+CCG) and based on the geochemistry of REE as volcanic arc granitoids, and collision granitoids (VAG+SYN+COLG) specially post collision granitoids. The chondrite normalized spider diagram of granitoid rocks of NW Takestan including samples having intermediate to acidic compositions, are enriched by LREE such as La, Ce, Pr to HREE such as Tm, Yb, Lu. Negative anomaly of Eu shows not only governing of the restoration of the terms in magma, but also display the entrance of the double capacity of this element in feldspar structure especially plagioclase. The normalized pattern of these granitoids with ORG shows their enrichment of LILE specially K, Rb, and Ba against HFSE (Nb & Zr) and HREE such as Y, Yb. This pattern is similar to the granitoid patterns, which are formed by the volcanic arc granitoids (VAG).
Original Research Paper
R Ferdowsi; M Moayyed; A Kamali
Abstract
The Kalaibar nepheline syenitic body is located in East Azabaijan, NW of Iran. This alkalic body generally intruded semi-deeply into the Cretaceous and Eocene volcanic and sedimentary rocks. Based upon chemical classification, the composition of studied intrusive bodies are nephelines bearing syenite ...
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The Kalaibar nepheline syenitic body is located in East Azabaijan, NW of Iran. This alkalic body generally intruded semi-deeply into the Cretaceous and Eocene volcanic and sedimentary rocks. Based upon chemical classification, the composition of studied intrusive bodies are nephelines bearing syenite (nepheline syenite), nepheline bearing gabbro (alkalic gabbro), syenite and quartz monzonite (syeno-diorite) in order of abundance. In addition, the composition of accompanying dyke and pegmatitic units are nepheline syenite, syenodiorite and gabbro. Common textures of studied rocks are prophyritic granular and granular and accompanying dykes have fine grained granular, porphyritic and coarse grained granular textures. According to mineralographic studies and XRD analysis results, the main mineral phases contain orthoclase, albite, nepheline, oligoclase, hornblend, augite and Melanite. The nature of parent magma of these intrusives is potassium rich alkaline, metaluminous and miaskitic. Petrographical and geochemical studies based upon accessory and rare elements illustrate that these intrusives formed in a subduction or post collision related tectonic setting, which their lithological variety is justifiable by fractionation crystallization. The studied intrusives show the enrichment of Zn, Ba, Sr, Th and Pb and enrichment of Co, Sr, Pb and V in accompanying dykes. LREEs relative to HREEs show enrichment. Comparison of studied body with some other ones of corresponding type of the world in terms of the amount of accessory and rare elements shows that the Kalaibar nepheline syenitic body is resemble to the central Anatoly (Turkey), Zijinshan (china) and Musale (India) bodies.
Original Research Paper
D Esmaeily; M Heidari; R Maghdour-Mashhour
Abstract
The Sikhoran Mafic–Ultramafic complex is located in the Sanandaj – Sirjan structural zone. The complex consists of two main rock units: the lower harzburgite - porphyroclastic dunite unit and the upper layered gabbroic cumulate unit. The microstructures and geochemical evidences provided ...
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The Sikhoran Mafic–Ultramafic complex is located in the Sanandaj – Sirjan structural zone. The complex consists of two main rock units: the lower harzburgite - porphyroclastic dunite unit and the upper layered gabbroic cumulate unit. The microstructures and geochemical evidences provided a better understanding of serpentinization and emplacement processes of this complex. The petrographic studies revealed three microstructural types including: High T solid slate microstructure, which occurs mainly in NE of the porphyroclastic dunite unit, Low T solid state microstructure in NE and central parts of dunites – harzburgites, and finally mylonitic - sub mylonitic microstructures, which mainly found in harzburgite unit. Moreover, the vein microstructures outcrop in the mylonitic- submylonitic zone. The veins have been formed by two processes of crack seal and dissolution. Deformations have occurred mainly around the Ashin fault. Hydrothermal fluids have resulted in serpentinization and mobility of iron and also other elements from ferromagnesian minerals of primary peridotites. Serpentinites show the SiO2amountof 38.8-41.7 wt%, and also depletion of Al2O3 and CaO. The depletion in CaO (0.3-0.9 wt %) and Al2O3 (0.1- 1.3) and enrichment in Cr and Ni indicate the depleted parent rock of mantle harzburgite or dunite, and a supra- subduction zone in Cr - TiO2 diagram.
Original Research Paper
E Mohammadi; Gh Ghorbani; H Shafaii Moghadam
Abstract
The studied volcanic rocks are situated in NW of the Sabzevar, mainly at southern domains of the Northern Sabzevar ophiolitic belt. Abundant rhyolitic domes (e.g., Sarough, Zard-Kuhi, Kuh-e-Sefid Mehr and Nahr domes) in the southern margin of the Davarzan-Sabzevar ophiolitic belt crosscut the above-mentioned ...
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The studied volcanic rocks are situated in NW of the Sabzevar, mainly at southern domains of the Northern Sabzevar ophiolitic belt. Abundant rhyolitic domes (e.g., Sarough, Zard-Kuhi, Kuh-e-Sefid Mehr and Nahr domes) in the southern margin of the Davarzan-Sabzevar ophiolitic belt crosscut the above-mentioned ophiolitic rocks. The Geochemical signatures of these volcanic rocks including enrichment in LREEs and LILEs relative to HREEs and HFSEs, depletion in TNT (Ta-Nb-Ti) elements, metaluminous to peraluminous and medium to high K-calc-alkaline characteristics, and their positions in discrimination tectonomagmatic diagrams, displayed that these rocks derived from a subduction-related environment. These adakitic domes are characterized by adakitic signatures (e.g., 69.2 wt.% < SiO2، 14.7 wt.% < Al2O3، MgO < 0.35 wt.% ، Sr > 273 ppm, enrichment in LREEs and LILEs, depletion in Y and HREE (Y < 9.7 and Yb < 0.86( and high ratio of Sr/Y > 58 and La/Yb > 12.1 and belong to high silica adakites (SiO2 ≥ 69.2 wt.%, MgO = 0.19-0.31 wt.% ، CaO+Na2O < 7.62 wt.% and Sr = 273-936). Nd-Sr-Pb isotopes characteristics of the adakitic rocks show similarities to a MORB-type and/or PREMA mantle source, highlighting that their magma (s) is originated from a depleted MORB-type mantle source associated with minor contamination with crustal materials. The geochemical and isotopes characteristics of the Sabzevar adakitic rocks display derivation from partial melting of subducted oceanic crust (garnet amphibolite) associated with subsequent fractional crystallization.
Original Research Paper
B Taghipour; M Nejadhadad; M.A Makizadeh; M Noghreian; P Rahimi
Abstract
Dunite and serpentinized harzburgite from northwest of the Neyriz ophiolites are host rocks of some podiform chromite deposits in Cheshmeh-Bid area. These chromite deposits occurred as aligned massive lenses in various sizes. The most important ore textures are massive, nodular, layered and disseminated ...
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Dunite and serpentinized harzburgite from northwest of the Neyriz ophiolites are host rocks of some podiform chromite deposits in Cheshmeh-Bid area. These chromite deposits occurred as aligned massive lenses in various sizes. The most important ore textures are massive, nodular, layered and disseminated grains. These textures are goodevidences of crystals settling crystals during the process of magma cooling in the chamber. The mineralogical studies revealed that the pyroxene melting tookplace in the peridotite host rock and olivine is recrystallized in dunite envelope. Mineral chemistry of chromite indicates high Cr number(72-77), high Mg number(69-62) and low TiO2 content(0.04-0.14 %) in chromite samples. These amounts are comparable with those chromitites, which areformed from the high partial melting rate of mantle. The medium amount of PGE determined about 212ppb, which is much lessthan the Tang-e-Hana chromite (1556ppb) deposits. The trace element content of chromitite samples and dunite envelope like Ga, V, Zn, Co, Ni and Mn are between 17-24, 466-842, 852-1048, 22-84, 115-171, and 852-1220 ppm respectively. The U shape of REY pattern indicates the interaction of high volatile and REE bearing melt(boninitic source of parent magma) with host rock. Therefore,the Cheshmeh-Bid chromitite resulted likely from the intrusion of boninitic magma ofprimary mantle with high partial melting in the peridotite host rock. The geotectonic setting is above supra-subduction zone of island arc.
Original Research Paper
R Samadi; H Mirnejad; A.A Baharifar; S.J Sheikh Zakariaee
Abstract
The fibrolite garnet staurolite mica schist and staurolite garnet mica schist cropped out around the northwest of Khalaj, south of Mashhad in a SE_NW direction along the metamorphic complex of Kuh-e-Majuni. They have similar mineralogy and consist of quartz, annite, staurolite, almandine, muscovite, ...
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The fibrolite garnet staurolite mica schist and staurolite garnet mica schist cropped out around the northwest of Khalaj, south of Mashhad in a SE_NW direction along the metamorphic complex of Kuh-e-Majuni. They have similar mineralogy and consist of quartz, annite, staurolite, almandine, muscovite, zircon, and ilmenite; however, fibrolite in fibrolite garnet staurolite mica schist, and chlorite and tourmaline in the staurolite garnet mica schist are additionally found. Application of garnet - biotite thermometry and GBMAQ barometry indicates the temperatures and pressures of 560 and 605 °C / 3.5 and 5 kilobar for fibrolite garnet staurolite mica schist and temperatures of 489 and 547 °C (in 3.5 to 5 kilobar) for the staurolite garnet mica schist. Pressure and temperature increasing during the garnet growth indicates the effect of regional and contact thermal metamorphism on these rocks. Based on mineral paragenesis in KFMASH system, the metamorphic degree of regional metamorphism was about lower amphibolite (in staurolite garnet mica schist) to middle amphibolite facies (in fibrolite garnet staurolite mica schist). Meanwhile, intrusion of the Khalaj granitoid and its thermal diffusion raised the metamorphic temperature up to lower amphibolite facies (in staurolite garnet mica schist) and middle amphibolite facies (in fibrolite garnet staurolite mica schist), and consequently, this caused the fibrolite formation in the sample close to the pluton (i.e. fibrolite garnet staurolite mica schist).
Original Research Paper
M Sheibi; P Majidi
Abstract
The Challu granitoidic pluton composes of two monzodiorite and quart diorite units, injected into the Eocene volcanic rocks in south of Damghan. Emplacement mechanism of this pluton has been investigated by the anisotropy of magnetite susceptibility method. The measured mean value of bulk susceptibility ...
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The Challu granitoidic pluton composes of two monzodiorite and quart diorite units, injected into the Eocene volcanic rocks in south of Damghan. Emplacement mechanism of this pluton has been investigated by the anisotropy of magnetite susceptibility method. The measured mean value of bulk susceptibility (Km in µSI) in fresh quart zdiorites and monzonites are 31608 and 33726, respectively and then the pluton belongs to the ferromagnetite granites. In this granitoidic body, magnetite is the main carrier of magnetic susceptibility and biotite and pyroxene are the other accessory factors of magnetite nature. The field observation along with petrographical and magnetic fabric investigations reveal that the mentioned pluton emplaced at two stages with two different mechanisms. Monzodioritic unit with dominant porphyroidic texture and NS lineation trend and foliation strike parallel to the margin of the pluton emplaced along tensional gash of one dextral shear zone. Quartz dioritic unit at the same time or a time after monzodiorite emplaced as dyke. The magnetic fabric pattern, oblate ellipsoid shape as well as predominance of trachytoidic texture in this unit correspond with the inverse fabric dyking pattern and the orientation of plagioclase show magma flow. The magnetic susceptibility has been decreased in the stations that subjected to the hydrothermal alteration either by reduction of size of magnetite crystals or conversion of magnetite to hematite. The microstructures in the pluton are mainly magmatic and show high melt fraction to crystal during the emplacement or absence of tectonic stress after full crystallization.
Original Research Paper
K Shiaian; J Ghalamghash; M Vosoughi Abediny; F Masoudi
Abstract
The Bazman volcano is located in the Makran Magmatic Arc. The pyroclastic rocks and lava with rhyodacitic to basaltic composition and calc-alkaline affinities erupted from the central and lateral craters of this volcano during the Quaternary period. The primitive mantle normalized Multi-elements diagrams ...
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The Bazman volcano is located in the Makran Magmatic Arc. The pyroclastic rocks and lava with rhyodacitic to basaltic composition and calc-alkaline affinities erupted from the central and lateral craters of this volcano during the Quaternary period. The primitive mantle normalized Multi-elements diagrams show a relatively high abundance of LIL relative to HFS incompatible elements with negative anomalies of Nb and Ti. Their chondrite–normalized REE patterns are slightly enriched in LREE relative to HREE with negative Eu anomalies. These geochemical features suggest that the volcanic rocks of bazman formed in a subduction setting by partial melting of metasomatized mantle. On the base of La/Yb vs Dy/Yb and La/Sm vs Sm/Yb diagrams the sources of the magmas is phlogopite-spinel-lherzolite or/and phlogopite-garnet- lherzolite.
Original Research Paper
Sh Khalili Mobarhan; H Ahmadipour
Abstract
The Bidkhan stratovolcano in the southeast of Urmia-Dokhtar volcanic belt (Kerman province) contains complex successions of lava flows and pyroclastic deposits. It belongs to Miocene-Pliocene periods and so, its edifice is relatively intact. Therefore, it is a suitable target for volcanic facial studies. ...
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The Bidkhan stratovolcano in the southeast of Urmia-Dokhtar volcanic belt (Kerman province) contains complex successions of lava flows and pyroclastic deposits. It belongs to Miocene-Pliocene periods and so, its edifice is relatively intact. Therefore, it is a suitable target for volcanic facial studies. Facies analyses showed that the Bidkhan structure could be divided into four facies. The Central Facies is located in the Bidkhan caldera and contains the special lithological units such as altered subvolcanic intrusion, lava breccias and radial and circular dykes. The Proximal Facies has been developed around the caldera as elevated steep cliffs and clearly shows stratification. In this facies, there are thick successions of lava flows, and pyroclastic fall, flow and surge deposits. The most voluminous facies in Bidkhan is Medial Facies. It is mainly consists of numerous layers of pyroclastic deposits and lava flows along with the lahars. Thin Bidkhan Distal Facies contains the coarse-grained alluvial deposits that have been formed due to reworking of primary volcanic products by streams. Facies analyses showed that the Bidkhan volcano has been formed by several explosive eruption phases and some eruptions have been done in the presence of water. Features such as strong welding and color of pyroclastic deposits indicate that the volcanic products formed in high temperature subaerial conditions. The Bidkhan Central Facies can be suitable place for Cu-Mo porphyry exploration.
Original Research Paper
M Abolipour; E Rastad; N Rashidnejad Omran
Abstract
The Koshkoiye district is located in Dehaj-Sardoiye subzone of Uromieh-Dokhtar Magmatic Arc in Kerman region. There are five active mines including Palangi, Cheshmeh Khezr, Tale Dozi, Abedini, and Eghbali. The geometry of mineralization is strata-bound and hosted in the Eocene Pyrobitumen-bearing porphyritic ...
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The Koshkoiye district is located in Dehaj-Sardoiye subzone of Uromieh-Dokhtar Magmatic Arc in Kerman region. There are five active mines including Palangi, Cheshmeh Khezr, Tale Dozi, Abedini, and Eghbali. The geometry of mineralization is strata-bound and hosted in the Eocene Pyrobitumen-bearing porphyritic andesite. Bornite, chalcocite and chalcopyrite are important Cu-sulfides together with hematite. The textures and structures of mineralization are open space filling, disseminated, vein-veinlet and replacement. According to geochemical study, tectonic setting of Koshkoiye copper district is extensional back-arc, which generated together with subduction of the Dehaj-Sardoiye subzone. Abundant of Cu, Pb and Ag elements is up to 600, 5 and 2 ppm in fresh porphyritic andesite. Fluid inclusion microtermometry indicates probably basinal brine source for ore-forming fluids. The copper mines in the Koshkoiye district have a lot of similarity in mineralogy, minor element, host rock, textures and structures, geometry and genesis with each other and the Manto-type copper mineralization of the world. This type of copper mineralization in the Koshkoiye district of Rafsanjan indicates the importance of volcanic processes in copper mineralization plus plutonic processes that produces porphyry systems in the Dehaj-Sardoiye subzone. The presence of pyrobitumen in porphyritic andesite host rock causes these deposits exposure in a few pyrobitumen-bearing andesitic hosted copper deposits of the world. There are only a few of these deposits in the world and dominantly located in Chile. Two important stages could be separated for mineralization in these deposits like the other Manto-type copper mineralization. The first stage includes processes, which caused to generate pyrite and pyrobitumen in matrix of porphyritic andesite and produced a reduction state in it. The Second stage was related to importance of generation of the Cu-rich oxidation fluids, which replaced the first stage pyrite and pyrobitumen by Cu-sulfides and hematite and caused copper mineralization.
Original Research Paper
F Sarjoughian; A Kananian; A Esna-Ashari; J Ahmadian
Abstract
The Kuh-e Dom intrusion with calc-alkaline nature, in the northeast of Ardestan is located in the central part of the Urumieh-Dokhtar Magmatic Arc and includes the felsic and intermediate-mafic units. The felsic unit consists of monzogranite, granodiorite, quartz monzonite and quartz monzodiorite, whereas ...
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The Kuh-e Dom intrusion with calc-alkaline nature, in the northeast of Ardestan is located in the central part of the Urumieh-Dokhtar Magmatic Arc and includes the felsic and intermediate-mafic units. The felsic unit consists of monzogranite, granodiorite, quartz monzonite and quartz monzodiorite, whereas the intermediate-basic rocks comprise gabbro, diorite, quartz diorite, monzodiorite and monzonite. The acidic dykes intruded this intrusion and its surrounding rocks. The various mafic microgranular enclaves of dioritic, quartz dioritic, monzodioritic and quartz monzodioritic composition exposed in the acidic rocks. The zircon U-Pb dating by the LA-ICP-MS method indicates that the ages of the felsic rocks, intermediate-mafic rocks, acidic dikes and enclaves are 51.1±0.4 Ma, 53.9±0.4 Ma, 49.95±0.64 Ma and 50.3±0.8 Ma respectively. These ages are in good agreement with the lower-middle Eocene age of the intrusive body, which is simultaneous with subduction of the Neotethys oceanic crust underneath the Central Iran. This result is in agreement with the previous geochemical result.
Original Research Paper
M Keshavarz Hedayati; M.H Emami; A.R Karimi Bavand Pour; Kh Bahar Firouzi
Abstract
The microgabbroic sills and dikes have injected into the late Cretaceous limestones along Shafarud. Based on the textural and mineralogical features, they are divided into four groups: micro olivine gabbro, microgabbro, microgabbro-diorite, and diabase. The main minerals in these rocks are olivine, clinopyroxene, ...
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The microgabbroic sills and dikes have injected into the late Cretaceous limestones along Shafarud. Based on the textural and mineralogical features, they are divided into four groups: micro olivine gabbro, microgabbro, microgabbro-diorite, and diabase. The main minerals in these rocks are olivine, clinopyroxene, amphibole, and plagioclase. The spider diagrams show that the primary mafic magma is probably originated from the asthenosphere, but due to contamination with upper continental crust during eruption has been modified to calc-alkaline. As a result, depletion of Nb and enrichment in Pb, Rb, Cs, Th, and U is observed. Discrimination diagrams show that the primary alkaline microgabbros influenced by AFC process and modified to calc-alkaline rocks. The presences of pyroclastic enclaves in diabasic rocks indicate that the diabasic rocks are younger than the pyroclastic rocks.
Original Research Paper
M.R Omidvar Eshkalak; A.A Mokhtari
Abstract
The studied area is located in the southeastern end of the Sahand- Bazman Magmatic Belt in the north of Bazman volcano. This area composed of Miocene volcanic rocks including andesitic to dacitic lavas along with tuffaceous sandstone, ignimbrite, agglomerate, tuff and siltstone that underwent propyilitic, ...
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The studied area is located in the southeastern end of the Sahand- Bazman Magmatic Belt in the north of Bazman volcano. This area composed of Miocene volcanic rocks including andesitic to dacitic lavas along with tuffaceous sandstone, ignimbrite, agglomerate, tuff and siltstone that underwent propyilitic, argillic, sericitic, carbonatic and silicified alterations. Predominant form of the mineralization is silica veins and hydrothermal breccia, which crop out within the alteration zones. The textures within the silica veins include coliform, vuggy, stratiform, banded and hydrothermal breccias. The results of sample analysis demonstrate that hydrothermal breccias have the highest grades of Au (up to 27.6 ppm), and the silica veins with banded texture and fine grained sulfide bearing silica veins are other important Au- bearing mineralization in the next orders. The geochemical investigations demonstrate good positive correlation between Au and Ag, Sb, As, Pb, Zn, Mo, Bi and Hg in the Au- bearing silica veins. The fluid inclusion studies on silica veins with banded texture indicate that the salinity of fluids is 1.22-7.77 W% NaCl, and homogenization temperature is 190-296◦C. Based on the field evidences along with mineralogy, textures and structures of silica veins, geochemical and fluid inclusion investigations, the Au mineralization in the north of Bazman can be classified as low sulfidation epithermal gold deposits.
Original Research Paper
H Hadizadeh1; A.A Calagari; N Nezafati; H Mollaei; H Azmi
Abstract
The Neian epithermal deposit in northwest of the Lut block is located in ~35 km southwest of Bejestan. The studies done on this deposit indicate the development of zonation in altered rocks around the ore-bearing siliceous veins and the existence of silicic (quartz, chalcedony, adularia, calcite, illite, ...
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The Neian epithermal deposit in northwest of the Lut block is located in ~35 km southwest of Bejestan. The studies done on this deposit indicate the development of zonation in altered rocks around the ore-bearing siliceous veins and the existence of silicic (quartz, chalcedony, adularia, calcite, illite, and sericite), silicic-argillic (quartz, adularia, illite, sericite, and pyrite), argillic (illite, quartz, calcite, adularia, sericite, kaolinite, smectite, and chlorite), and propylitic (chlorite, calcite, albite, epidote, quartz, and smectite) alterations as the major alteration zones in this deposit that were formed during the five stages. Th geochemical diagrams, molar elemental ratios, and petrographic consideration illustrate the presence of transitional transformation and mineral conversion arrays during the development of hydrothermal system at Neian. Consideration of these diagrams indicate a wide spread of argillic and silicic and a relatively limited extent propylitic alteration zones in the Neian deposit. These diagrams also show that the mineral arrangements such as plagioclase-illite, plagioclase-adularia, illite-adularia, and plagioclase-smectite were developed during the prograde stages, whereas adularia-illite arrangement was formed during the retrograde (waning) stages of hydrothermal system. Permeability, high water/rock ratio in the host rocks (generated by faulting and the presence of extensive pyroclastic rocks) are the main factors for development of alteration zones and formation of widespread adularia in the area. In addition, considering the mineralogical composition of the deposit, the presence of minerals such as adularia and illite in the central and kaolinite in the peripheral part of the system may suggest that they were formed by the fluids having temperatures > 220 °C and <140 °C, respectively. The presence of mineral assemblage of quartz, adularia, illite, pyrite, chlorite, and calcite may reflect the involvement of upward flowing Chloride-bearing fluids with pH ranging from almost neutral to moderately alkaline. The contemporaneous formation of calcite, smectite, illite, and kaolinite in peripheral parts of the system was resulted by the reaction of CO2-rich fluids (containing hot vapors) with the host rocks. Increasing of temperature and potassium metasomatism in the central parts of the system caused widespread formation of illite at the first stage of alteration and of adularia-illite at the second (maximum K-metasomatism) during the geothermal activity at Neian. Concurrent with the waning stage of hydrothermal alteration and decreasing of K-metasomatism, illite replaced adularia again. The prevalence of conditions (for a long period of time) suitable for stability of illite may account for the greater abundance and extent of this mineral relative to adularia in the host rocks of Neian deposit.
Original Research Paper
M Emami Jafari; M Mehrpartou; A Akbarpoor; B Shamsi
Abstract
BLEGmethod is one ofmodern methodsusedfor goldgeochemicalexplorationstudies.Themethod has helped to locate many low grade gold deposits. The significant change of the method compared to common geochemical exploration methods is to use of large volumes ofsamples regardless of their sizeandlow densityof ...
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BLEGmethod is one ofmodern methodsusedfor goldgeochemicalexplorationstudies.Themethod has helped to locate many low grade gold deposits. The significant change of the method compared to common geochemical exploration methods is to use of large volumes ofsamples regardless of their sizeandlow densityof sampling.In order to evaluate the efficiency of the BLEG geochemical method with stream sediment method, 1:100000 SiahRud sheet was chosen in geological region of Azarbaijan in a district that geological map and geochemical exploration has already been carried out.The study area is 1850 km2, located in a mountainous area of northwest Iran in the Eastern-Azarbaijan province (NW of Ahar city).The rock units of the area consist mainly of the Upper Cretaceous limestone and flysch complex, Oligocene intrusive bodies and Eocene volcanic-sedimentary rocks. The Oligocene intrusive bodies are the most important igneous unit in the area.In this project, 168 BLEG samples and 103 stream sediment samples (silt samples) were prepared and studied. The range gold values in BLEG samples are from 0.1 to20 ppb, and in the stream sediment samples from 3 to459 ppb.The results ofsampling and analysis present four districts with high anomalous degrees: 1) Anigh-GharehChilar district, 2) Namnegh district, 3) Eshtobin district, and 4) Andrian or MiveRud district. Analysis ofthe stream sedimentsamplesrepresentshigh value of Cu andAu. Correlation of the elements in stream sediments taken from the Anigh-GharehChilar district represents high correlation of gold with arsenic, copper and leads elements. Copper also shows a high correlation with molybdenum, which is in accordance with mineralization of this area.
Original Research Paper
Z Solaymani; N Taghipour
Abstract
The Olang area is located in 70 km of northeast Shahroud. This area is situated in Gheshlagh Olang syncline, which is a member of the EasternAlborzCoalBasin. The optical microscopes and X-ray diffraction (XRD) analysis on coal and coal ash samples and also SEM-EDX results revealed kaolinite, quartz, ...
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The Olang area is located in 70 km of northeast Shahroud. This area is situated in Gheshlagh Olang syncline, which is a member of the EasternAlborzCoalBasin. The optical microscopes and X-ray diffraction (XRD) analysis on coal and coal ash samples and also SEM-EDX results revealed kaolinite, quartz, siderite, pyrite, biotite, chlorite and illite minerals in coal seams at the Olang coal mines. Pyrite is observed as syngenetic (framboidal) and epigenetic (filling of the cell cavity, vein, and veinlet).The abundance of syngenetic siderite and absent sulphate minerals is usually thought to indicate deposition of the coal mainly under nonmarine conditions, or at least under the influence of swamp or formation waters with low sulphate content. The study of 15 potentially hazardous trace elements (PHTEs) includes: (Ba ®1054.7 ppm), (Co ®51.32 ppm), (Cr ®161.1 ppm), (Cu ®129.3 ppm), (Mn ®1600 ppm), (Mo ®19.56 ppm), (Sn ® 4.78 ppm), (Ni ®139.7 ppm), (Pb ® 48 ppm), (Tl ®1.36 ppm), (Th ®27.6 ppm), (U ® 9.45 ppm), (V ® 232.9 ppm), (Zn ®101/78 ppm(, (P® 6500 ppm) in coal ash deposits of the Olang region compared with the average of the world coal ash, shales, soils and also crustal Clarke. The results show that these coals are enriched in Mn, Mo, U, Pb, Zn and P and are dangerous elements.
Original Research Paper
H Atapour
Abstract
To assess the environmental impacts of essential and toxic elements on the 1:50000 scale map of the urban areas of Kerman city, 220 samples of residual and nonresidual soils were collected by systematic random sampling method.Based on analytical data, high values of Ca (23.6 %wt), Na (3.86 %wt), K (2.36 ...
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To assess the environmental impacts of essential and toxic elements on the 1:50000 scale map of the urban areas of Kerman city, 220 samples of residual and nonresidual soils were collected by systematic random sampling method.Based on analytical data, high values of Ca (23.6 %wt), Na (3.86 %wt), K (2.36 %wt), Li (49.18 ppm), B (65.8 ppm), and low values of Se (0.12 ppm) in residual soils indicate calcareous and silty – clayey (playa) nature of the soils around the Kerman city.Anthropogenic polluted soil samples around the gasoline stations are enriched in Pb (84 ppm), Zn (250 ppm), Rb (983 ppm), B(158 ppm). The high values of Cu (715 ppm), Mo (4.26 ppm), Pb (10125 ppm), Zn (275 ppm), Sn (100.3 ppm),W (4.36 ppm), As (19.6 ppm) and Li (70.4 ppm) from themachinery battery and manufacture stations are noteworthy. The soil samples close to the machinery paint workingsites contain 0.38 wt% S, 205 ppm Cu, 2.69 ppm Mo, 318 ppm Pb, 310 ppm Zn, 19.3 ppm Sn, 3.25ppm W, 20.3 ppm As, 4.65 ppm Sb, 80 ppm Li and 115.4 ppm B. The high values of Zn (1903 ppm) are indicative of agricultural soils in the pistachio gardens. The soils developed on the disposal wastes include 7.58 wt% S, 392 ppm Pb, 275 ppm Zn, 26.7 ppm As, 5.32 ppm Sb, 807 ppm Rb and 651 ppm Sr, respectively. The enrichment factors follow: Pb (1358), Cu (72), Mo (8.94)and Sn (242) in soils around the machinery battery and manufacture stations, As (5.7)in soils close to gasoline stations, Zn (20.8) in agricultural soils and Sb (10.24) in rail road soils indicate thehighly polluted soils.The geoaccumulation indexes forsoilsaround themachinery battery and manufacture stations includeCu (3.96), Pb (8.18), Sn (4.48), W (2.09) and Zn(0.83) in pistachio gardensreflect the highly polluted nature of the soils.
Original Research Paper
Z Miriyan; M Lotfi; A.A Shabani; M.A.A Mokhtari; E Haj Molla Ali
Abstract
The Kharengun area is located in the Yazd province, Central Iran, 130 km east of Yazd city and 65 km northeast of Bafq city. Mineralization in Kharengun area occurred within calcic and dolomitic units of the Rizou Formation (equivalent to Soltaniyeh Formation) of upper Precambrian- lower Cambrian age. ...
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The Kharengun area is located in the Yazd province, Central Iran, 130 km east of Yazd city and 65 km northeast of Bafq city. Mineralization in Kharengun area occurred within calcic and dolomitic units of the Rizou Formation (equivalent to Soltaniyeh Formation) of upper Precambrian- lower Cambrian age. The ore minerals of this deposit includes smithsonite and hemimorphite, that is stratabound and formed epigenetically along layers and laminations of carbonate host rocks. The maximum grade of zinc in samples taken from the study area exceeds 36% and geochemical studies indicate significant absence of Pb along with Zn in this area. Therefore, the Kharengun mineralization is a monomineral Zn zone.The fluid inclusion microthermometry investments explain the role of meteoric waters in generation of this deposit. The homogenization temperatures and salinity of the inclusions show the similarity between these fluids and the solutions responsiblefor the development of epithermal deposits.The Zn mineralization present in this zone belongs to the nonsulfide supergene deposit class, and a mixture of wallrock replacement and direct replacement subclasses.
Original Research Paper
Gh Sohrabi; M.R Hosseinzadeh; A.A Calagari; B Hadjalilu
Abstract
The study area is located in north of East-Azarabaidjan (northwest of Iran). The most important intrusive bodies in the area include the Gharehdagh and Shivardagh batholiths and porphyry stocks of Sungun and Haftcheshmeh. The petrological and petrographical studies show that the composition of intrusives ...
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The study area is located in north of East-Azarabaidjan (northwest of Iran). The most important intrusive bodies in the area include the Gharehdagh and Shivardagh batholiths and porphyry stocks of Sungun and Haftcheshmeh. The petrological and petrographical studies show that the composition of intrusives varies from gabbro through diorite, monzonite, and granodiorite to granite. All bodies are I-type and mostly metaluminous and calc-alkaline with medium to high potassium belonging to volcanic arcs. The most important alterations in ore-bearing areas include silicic, potassic, propylitic, phyllic, and argillic. Mo mineralization occurred mostly in quartz veins and veinlets within the potassic zone in porphyry systems and veins and also in endoskarn associated with garnet skarns. The amount of Mo increases in differentiated and biotite-bearing acidic bodies that have high values of Si, K, Rb, and REEs. The intrusive bodies enriched with K, Rb, and Ba and depleted in Zr, Ta, Y, Yb, and Nb elements indicate metasomatism of the upper mantle by subducting oceanic crust and subsequent generation of magma and its passes through relatively thick crust. The bodies bearing Mo mineralization are located mainly in the center of batholiths and have quartz monzonitic and granodioritic compositions.
Original Research Paper
N Zaheri; A.R Zzarasvandi; M Karevani; M Karevani; H Pourkaseb; F Rastmanesh
Abstract
The Aligudarz region is located in middle part of the Sanandaj-Sirjan Zone. During and before the Jurassic time, a variety of Cu, Fe, Zn-Pb and Ba mineralization are formed in this area due to tectono-magmatic activities. This diversity of mineralizations with volcano-plutonic activities caused some ...
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The Aligudarz region is located in middle part of the Sanandaj-Sirjan Zone. During and before the Jurassic time, a variety of Cu, Fe, Zn-Pb and Ba mineralization are formed in this area due to tectono-magmatic activities. This diversity of mineralizations with volcano-plutonic activities caused some complexities and ambiguities in geology-metallogeny evolution of the region. In this way, the aim of this study was investigation of geological evolution and its relation with mineralization and tectono-magmatic evolution of the Aligudarz region. The field and petrographic observations show that mineralization composition consist of barite with sulfide minerals (chalcopyrite, pyrite and covellite) and Fe-oxides in the Farsesh deposit withPermian carbonate host rock in the Farsesh area; sphalerite, galena and chalcopyrite in the Jurassic phylite, slate and meta-sandstone host rocks (Gol-e Zard deposit) and Cu mineralization associated with andesite rocks. In order to approach these aims, sampling for petrographical and geochemical studies with ICP-MS was done from each ore body separately. In addition, the granitoid rocks of the region were considered. In the Gol-e Zard Zn-Pb deposit, REE pattern represent enrichment of LREEs and La/Lu>1. The metamorphic host-rocks show positive Ce and negative Eu anomalies, whereas sphalerite, galena, chalcopyrite and quartz show negative Eu and Ce anomalies. Lack of Eu anomalies indicates high Oxygen fugacity during the precipitation of these minerals. Therefore, according to similarity of REE pattern in host-rock and ores of the Gol-e Zard deposit, it seems REEs extracted from host rock and then added to mineralizing fluid. The chondrite normalized pattern of REEs in barite ores and its host rocks in the Farsesh deposit show LREE enrichment. The positive Eu and negative Ce anomalies indicate that hydrothermal fluids are the main fluids, which caused precipitation of barite inthe host rock. REE pattern of andesite rocks show the same magmatic source for these rocks. LREE enrichment in andesite samples, lack of Eu and Ce anomalies indicate that clinopyroxene and plagioclase were crystallized in the same time and Ce+3 extracted with other REEs from depositional environment. The chondrite normalized pattern of granite rocks in the region show LREE enrichment, negative Eu anomaly and lack of Ce anomaly, which can indicate that diffraction process was controlled by plagioclase crystallization during the granitoid generation. The chondrite normalized spider diagram show the same trend of depletion of HFSE and HRRE and enrichment of LREE and LILE for all of the samples, which represent occurrence of magmatism in the study area and indicate all of these mineralizations are related to the subduction zone. These studies indicate that there is geodynamically a genetic relation between mineralizing fluids and volcano-plutonic activities of the region during or before the Jurassic system.
Original Research Paper
S Ghaderi; E Rastad; N Rashidnezhad-Omran
Abstract
Tungsten (Cu-Au) mineralization of Southern Chah Palang (SCP) deposit, located in middle part of the Yazd block, occurred as vein-veinlet in normal fault zones, which cut the sandstones and shales of Early-Middle Jurassic Shemshak formation. Based on the mineral paragenesis and quartz type, color and ...
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Tungsten (Cu-Au) mineralization of Southern Chah Palang (SCP) deposit, located in middle part of the Yazd block, occurred as vein-veinlet in normal fault zones, which cut the sandstones and shales of Early-Middle Jurassic Shemshak formation. Based on the mineral paragenesis and quartz type, color and texture, ore-bearing veins can be divided into 1) k-feldspar, apatite (I) bearing milky-white quartz veins, 2) white quartz veins contain apatite (II), 3) hematite- white quartz veins and 4) late carbonate veins. Wolframite is the main tungsten ore mineral in the SCP deposit, which occurred in type 1 vein. Wolframite crystals are riched in Fe and have ferberite composition. Scheelite, as next tungsten ore mineral in SCP deposit, formed in 2nd generation and show significant enrichment in As. Scheelite (I) coexist with Wolframite in type 1 veins, and Scheelite (II) replace wolframite in its fractures and rims, also with arsenic-bearing phases occurred in type 2 veins. Gold in SCP deposit occurred as coexist with and/or fine inclusions in Scheelite (II). Other ore minerals that formed in type 2 veins include base metals and Fe sulfides, cobaltite, niccolite, Cu-Ni-Fe sulfides and native bismuth. Type 3 and 4 veins are white quartz-hematite and barren carbonate veins.
δ18 O of ore-forming fluids, which milky-white and white quartz and wolframite formed from them are 7.91-8.61‰, 5.86-6.76‰ and 3.44-6.94‰ respectively. Based on the oxygen isotope studies, progressive mixing of original magmatic fluids with meteoric waters cause precipitation of metals in veins.
Original Research Paper
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.
Original Research Paper
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.
Original Research Paper
S Maghfouri; E Rastad; F Mousivand
Original Research Paper
M.A Rajabzadeh; S Esmaeili
Abstract
The Jian copper deposit is hosted by the Permo-Triassic SurianVolcano-Sedimentary Complex on the eastern edge of the Sanandaj-SirjanMetamorphic Zone at a distance of 195 Km NE of Shiraz, southwestern Iran. The complex consists mainly of metabasalt, chlorite-quartz schist, chlorite-muscovite schist, ...
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The Jian copper deposit is hosted by the Permo-Triassic SurianVolcano-Sedimentary Complex on the eastern edge of the Sanandaj-SirjanMetamorphic Zone at a distance of 195 Km NE of Shiraz, southwestern Iran. The complex consists mainly of metabasalt, chlorite-quartz schist, chlorite-muscovite schist, mica schist and graphite schist. Pyrite is the most important sulfide and chalcopyrite is the major Cu-bearing mineral occurred as massive ores in lens to nearly tabular shapes and also as disseminations in veins and veinlets hosted by chlorite-quartz schist. On the basis of geochemical data the mobile elements (Na, k, Ba, Sr) and rare earth elements (REE) show an intense influence of mineralizing fluid on the host rocks. Co/Ni=8.02, Y/Ho (29.09-32.5) and Se/S*106
Original Research Paper
A Zahedi; M Boomeri
Abstract
The Panah-Kuh skarn is situated in 50km NW of Taft City in Yazd province. Inrtusion of granodioritic stock into the calcareous-dolomitic rocks of Permian Jamal Formation led to formation of calcic and magnesian skarns. The REE patterns of skarns and its forming garnets show Eu/Eu* and Ce/Ce*ratios increase ...
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The Panah-Kuh skarn is situated in 50km NW of Taft City in Yazd province. Inrtusion of granodioritic stock into the calcareous-dolomitic rocks of Permian Jamal Formation led to formation of calcic and magnesian skarns. The REE patterns of skarns and its forming garnets show Eu/Eu* and Ce/Ce*ratios increase with increasing of ∑REE, implying that skarn forming fluids were dominantly of magmatic origin, whereas (Pr/Yb)cn ratio decrease almost with increasing of ∑REE that implying the magmatic fluids granitoid-derived had not much REE during the Panah-Kuh skarn formation. Based on the fluid inclusion data from garnet, fluid temperature and salinity in the prograde stage vary between 308-380oC and 12.6-23.8 wt.% NaCl equivalent, respectively. Inclusion fluids in the calcite had lower temperature (T<280°C) and fluid salinity decline to 3.5 wt.% NaCl equivalent. Mixing and dilution of early magmatic fluids with external fluids (e.g., meteoric waters) caused a decrease in fluid temperature and salinity in latest stage of the skarn formation. Therefore, both REEs and fluid inclusions data suggest the dominant role of magmatic water in the formation of Panah-Kuh skarn.
Original Research Paper
S Alipour; S.N Mousavi; Y Rahimsouri
Abstract
Gharali lateritic iron-rich deposit is located in 20 km of Boukan city, West Azarbayedjan province. Eight surveyed stratiform outcrops stretched into thedolomite and limestone of Ruteh Formationin this region. Based on mineralogy, the analysed samples indicate scattered, veinlet, acicular, replacement, ...
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Gharali lateritic iron-rich deposit is located in 20 km of Boukan city, West Azarbayedjan province. Eight surveyed stratiform outcrops stretched into thedolomite and limestone of Ruteh Formationin this region. Based on mineralogy, the analysed samples indicate scattered, veinlet, acicular, replacement, spong, flow and cataclasic textures. The observed textures represents intense tectonic effects and non-residual origin.According to the chemical data, outcrops varies from iron-rich laterite to bearing ferritic bauxite, but in general the different diagrams put this ore deposit in a bauxite- laterite ore type. The results of geochemical data indicate enriched Fe, Al, and Ti and depletion Si, Ca, Na and K in ore deposits. REEs distribution pattern normalized to chondrite reveals weak differentiation of HREEs and LREEs with slightly enrichment of LREEs. The primary rock type has been considered to be a rich- iron mafic rocks (e.g. basaltic type). Following the removal of mobile elements, which have also resulted in increasing of Al2O3 andFe2O3, during alteration processes. The results show that clay minerals, Muscovite are not a suitable host for rare earth elements in the ore body. The results of chemical analyses and correlation coefficients show that neither rutile - anatase and nor clay minerals, muscovite, illite, and also Mn minerals play an important role in in hosting the REEs.The negatively correlated with Ti and Th (0.99) indicating lack of anatase titanium and thorium, and positive correlation of consentration between the Ti with Gd (0.91) shows that the consentration of rutile and anatase. Strong positive correlation of P-REEs indicate the role of secondary phosphate minerals consentration on rare earth elements except three elements such as Gd, Tb and Er in outcrops. The strong positive correlation of P with HREEs unravel phosphatic minerals role in enrichment of REEs except for three rare elements (Gd, Tb and Er) in outcrops.The Strong correlation between Gd, Tb and Er indicates their concentration with neomorphic minerals and their resistance nature against alteration and weathering are two main reasons for their difference distribution compared to other REEs inthese deposits.
Original Research Paper
S Shahbazi; M Ghaderi; N Rashidnejad-Omran
Abstract
The Bashkand iron deposit is located in 16 km southwest of Soltanieh, in Central Iran Structural Zone. The rock units in the area include alternations of metamorphosed sedimentary rocks of the Kahar Formation, Khorramdarreh granite and an andesitic dike. The major alteration types are argillic, potassic, ...
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The Bashkand iron deposit is located in 16 km southwest of Soltanieh, in Central Iran Structural Zone. The rock units in the area include alternations of metamorphosed sedimentary rocks of the Kahar Formation, Khorramdarreh granite and an andesitic dike. The major alteration types are argillic, potassic, chloritic, sericitic and quartz-carbonatic in composition. N30-50W trend and S30-50W dip mineralization conforms primary bedding, foliation of phyllites as well as parallel faults. Mineralogical paragenesis includes: 1) Grossularite, pyroxene, idocrase; 2) Andradite, pyroxene, forsterite, phlogopite, magnetite; 3) Tremolite, serpentine, epidote, talc, biotite, magnetite, specularite and sulfides, and they have been cut by quartz-carbonate veins. The presence of magnetite synchronous with quartz and feldspar in the intrusive body, unconformity in behavior pattern of Fe2O3 with SiO2 and Al2O3, and its conformity with other major oxides as well as Cu and Zn, similarity of REE pattern in the ore, the intrusive body and skarnized host rocks as well as no similarity with the less altered host rocks, are the signs of sourcing ore from the intrusive-deriven fluids. Mixing of these fluids with meteoric water together with increasing in oxygen fugacity in the retrograde metasomatism stage led to ore mineralization.
Original Research Paper
P Ketabi; S.S Mohammadi; M.H Zarrinkoub
Abstract
The volcanic–sub volcanic activities in the Shah Soleyman area located in southwest of Birjand, east of Iran have cropped out as two categories of Pyroclastic – lava and sub volcanic rocks. The pyroclastic rocks are tuff, agglomerate with breccias and volcanic rocks are andesite, trachy- ...
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The volcanic–sub volcanic activities in the Shah Soleyman area located in southwest of Birjand, east of Iran have cropped out as two categories of Pyroclastic – lava and sub volcanic rocks. The pyroclastic rocks are tuff, agglomerate with breccias and volcanic rocks are andesite, trachy- andesite and dacite. The porphyry and glomero- porphyric with micro granular to vitric groundmass are the main textures in these rocks. The porphyritic diorite is the unique sub volcanic unit in this area. Plagioclase, hornblende with oxidized rims, and biotite are the main phenocrysts. Sericitization, carbonatization and propylitic alterations are common in these rocks. Based on the geochemical study, these rocks have SiO2 in range of 56.8-61.9, high Al2O3 (16.5-18.1) and Sr (660-990), high Sr/Y (40.6-54.6), and low Y (16.1-19.7) that show adakites characteristic for the parent magmas. On the basis of geochemical characters, these rocks are high SiO2 adakites, which is considered to represent subducted basaltic slab melts that have reacted with peridotite during the ascent through mantle wedge. High ratio of LILE/HFSE, LREE/HREE and negative anomaly offor Nb and Ti show similarity with subduction- related magmatism. High Sr and negative anomalies of Ta, Nb, and Ti may be resulted from the lack of plagioclase and having iron and titanium oxides in the residual phase. The geochemical study showed that the source can be derived from subducted metamorphosed oceanic plate in east of Iran.
Original Research Paper
M.A Arian; J Faslebahar
Abstract
Geochemistry, mineralogy and mechanism of the mud volcanoes located in the southwestof the Caspian Sea (Azerbaijan country) have already been studiedwith aim of finding out theirorigin, but mud volcanoes of The Gomishanhaven’t been studied from thesepoints of view yet. In this research, mudof mud ...
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Geochemistry, mineralogy and mechanism of the mud volcanoes located in the southwestof the Caspian Sea (Azerbaijan country) have already been studiedwith aim of finding out theirorigin, but mud volcanoes of The Gomishanhaven’t been studied from thesepoints of view yet. In this research, mudof mud volcanoes and sea floor sediments forthe first time weresampled and studied to discover their origin. The results of mineralogical and geochemical studies, which carried out byXRD, XRF, ICP methodsshow that main minerals of the Qarnyaryq, Naftlycheh and Incheborun mud volcanoes and of sea floor sediments are quarts,calcite and albite and sub ordinaryminerals are mainly halite and clay minerals such assaponite,natrolite and muscovite.Therefore,it can be resulted that the three mud volcanoes have a common origin. The obtained results compared with present data from Dashgil mud volcano(Azerbaijan) and chemical characteristics of the Caspian Sea water.This comparison revealed that the elements of Na,K, Ca, and Al in these three mud volcanoes are richerand Cl element is poorerthan the Dashgil mud volcanoand the Caspian Sea.
