F. Hadavi; K. Khosrow Tehrani; S. Senemari
Abstract
Nannofossils are good for biostratigraphy, since they are abundant, planktonic, rapidly evolving and largely cosmopolitan especially in the Late Cretaceous. With respect to this reality and due to the lack of any precise paleontological study, the nannofossils of Gourpi Formation were investigated in ...
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Nannofossils are good for biostratigraphy, since they are abundant, planktonic, rapidly evolving and largely cosmopolitan especially in the Late Cretaceous. With respect to this reality and due to the lack of any precise paleontological study, the nannofossils of Gourpi Formation were investigated in the north of Gachsaran. This formation consists of marl and clay limestone.
In this study, for the first time, 23 genera and 43 species of nannofossils were identified. Based on the obtained nannofossils, the study section is Late Santonian to Late Maastrichtian in age corresponding to CC16-CC26.
B. Vosooghi; A. Rastbood
Abstract
In this research, the role of various existing tectonic plate and faulting motions in the middle-east region has been investigated on the geodetic data and its purpose is to estimate the contribution of these motions in the GPS velocity field of campaign global geodynamic network in the region of Iran ...
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In this research, the role of various existing tectonic plate and faulting motions in the middle-east region has been investigated on the geodetic data and its purpose is to estimate the contribution of these motions in the GPS velocity field of campaign global geodynamic network in the region of Iran using fracture mechanics concepts and dislocation modeling. For modeling the faulting data in the Middle-East region were decomposed to various categories by considering the tectonics of the region and were included in the model and the induced velocity field due to them were modeled and compared with GPS velocity field. Obtained results show that the contribution of Arabian plate in observational GPS velocity field is more than the contribution of Anatolian plateau faultings and inside faultings of Iran create an internal north-south compression component and a counterclockwise rotation component in the modeled velocity field. According to modeling results about 30% of GPS velocity field components are produced by Iranian inside faults, 60% by Arabian plate and 10% by Anatolian plate.
M. forutan; A. mansourian; M. Zareinejad; M. R. Sahebi
Abstract
Drilling in mine deposits has proven to be complicated, costly and time consuming process, hence it has identified the determining of optimum boreholes as a crucial issue in detailed studies. Because of some complexity in formation of mineral deposits, decreasing in risk and expenses of drilling ...
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Drilling in mine deposits has proven to be complicated, costly and time consuming process, hence it has identified the determining of optimum boreholes as a crucial issue in detailed studies. Because of some complexity in formation of mineral deposits, decreasing in risk and expenses of drilling may be continued by considering the wrapped condition of mineral deposits formation, followed by the integration of effective mineralization factors. By considering that in traditional methods of combination of mineralization’s factors like overlay and index overlay, is based on expert’s knowledge and expert knowledge is related to data accuracy, therefore, the accuracy of these methods could be remarkably decreased by large amount of data and noise. In order to solve these problems, utilization of flexible methods and powerful tools in data processing is obviously needed, especially in case of noise presence. Artificial Neural Networks are appropriate tools in large amount of data management and pattern recognition of noisy data, because of nonlinear, parallel and flexible architecture. So ANNs has been used in determining of proper position of boreholes. Neural Networks have various structures regarding their activation function and number of hidden layer and neurons in each layer. Consequently it is necessary to examine the performance of all these structures in determining the optimum position of boreholes.This paper represents a study on utilization GIS and four different Neural Networks namely: Multilayer peceptrons, Radial Basis Function, Generalized Neural Network and Probability Neural Network, for determining the position of boreholes of porphyry copper exploration in Chahfirouzeh region using cross correlation method. First, the mineralization factors are explained based on conceptual model of porphyry copper and predictor maps are produced, then, the training vectors are derived. After that, the networks are trained by geology, geochemistry and geophysics data layers. At the end, performances of the networks are compared. Implementation of Artificial Neural Networks reveals that two Neural Networks, GRNN and RBF, have the highest accuracy (approximately 80 to 83 %). Eventually, a potential map is produced by the best method.
M. Khosroshahi; F. Mahmoudi; M. T. Kashki
Abstract
In this article, we try to study deserts of Iran on the basis of geological specifications with the help of 1:100000, 1:250000 scaled maps of G.S.I and N.I.O.C using Geographical Information System (GIS) methodology. Then quaternary and evaporate formations in every study province were recognized. Saline ...
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In this article, we try to study deserts of Iran on the basis of geological specifications with the help of 1:100000, 1:250000 scaled maps of G.S.I and N.I.O.C using Geographical Information System (GIS) methodology. Then quaternary and evaporate formations in every study province were recognized. Saline and evaporatic formations were determined as “primary deserts”. With overlaying drainage network on the basic map of Quaternary formations, the secondary deserts were recognized. Both of these processes (The primary and secondary deserts) have formed provincial deserts. After recognition of the provincial deserts in the country map by utilization of the coordinate system of Iran's map georeferences and control check point all desert units were set up on the whole country map. Results showed that 12.6% (208041 km2) of Iran is known as deserts formed by evaporate formations.
Petrology
Ashraf Torkian; nafiseh salehi
Abstract
The Ahmadabad, Tahmoures and Ghareh-toreh volcanoes are part of the volcanic centers located on the Qorveh-Bijar axis and constitute a part of the magmatic outcrops of the northern arm of the Sanandaj Sirjan Zone, Hamadan-Tabriz. Volcanic rocks have basaltic composition and show porphyritic, microlithic ...
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The Ahmadabad, Tahmoures and Ghareh-toreh volcanoes are part of the volcanic centers located on the Qorveh-Bijar axis and constitute a part of the magmatic outcrops of the northern arm of the Sanandaj Sirjan Zone, Hamadan-Tabriz. Volcanic rocks have basaltic composition and show porphyritic, microlithic porphyry and glomeroporphyritic textures. Major phenocrysts include clinopyroxene and olivine. The abundance of clinopyroxene is found to be lower in Ghareh-toreh basalts, olivine is major phenocryst in this center. Clinopyroxene phenocrysts show normal, in some cases, reverse zoning and gulf corrosion indicating disequilibrium with the host's melt. The results of thermobarometric calculation (temperature and pressure) using clinopyroxene mineral indicate the temperatures of 1100-11300 °C and pressures of 3 to 11 kbar for Ahmadabad and Tahmoures volcanoes, and volcanic basalts at Ghareh-toreh reveal the temperature of 800 Up to 1100 °C and pressure of 0 to 3 kbar. The high oxygen fugacity in these rocks and the coherence of the temperature and pressure of the olivine phenocryst in this region with the temperature and pressure of the clinopyroxene in Ahmedabad and Tahmoures, all show that clinopyroxene crystals of Ghareh-toreh volcano formed at a lower depth and possibly in a shallow reservoir
R. Azimi; K. Seyed-Emami; A. Sadeghi
Abstract
The calpionellid biozonation within Shal and Kolur Formations in Shal region, SE Khalkhal are accomplished based on standard biozonation of Allemann et al. (1977). In this study, 5 biozones are introduced from Tithonian to Hauterivian:biozone. Biozone 1 belongs to Shal Formation ...
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The calpionellid biozonation within Shal and Kolur Formations in Shal region, SE Khalkhal are accomplished based on standard biozonation of Allemann et al. (1977). In this study, 5 biozones are introduced from Tithonian to Hauterivian:biozone. Biozone 1 belongs to Shal Formation and biozones 2 to 5 to Kolur Formation: 1- Crassicollaria intermedia Taxon Range Zone; Late Tithonian, 2- Calpionella alpina Acme Zone; Early Berriassian, 3- Calpionellopsis simplex - Calpionellites darderi Interval Zone; Late Berriassian to Early Valanginian, 4- Calpionellites darderi - Tintinopsella longa Interval Zone; Valanginian, 5- Tintinopsella longa - Tintinopsella carpathica Interval Zone; Late Valanginian- Hauterivian. Biozone 2 is also subdivided into the Calpionella alpina and Calpionella elliptica Subzones. Biozone 3 is subdivided into the Calpionellopsis simplex and Calpionellopsis oblonga Subzones. Based on this zonation, the Jurassic /Cretaceous boundary (Tithonian/ Berriassian) is defined at the Lower boundary of the Calpionella alpina zone which is equivalent to the Shal and Kolour Formations boundary.
S. Hashemi Tabatabaei; A. Mohamadi; A. S. Salamat
Abstract
Earthquake struck Bam city on 12/26/2004. Seismic microzonation of Bam city started with the aim to determine engineering geological and geotechnical characteristic in order to reduce the future earthquake disasters. The seismic microzonation included geoelectric, geoseismic, geotechnic, seismotechtonic, ...
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Earthquake struck Bam city on 12/26/2004. Seismic microzonation of Bam city started with the aim to determine engineering geological and geotechnical characteristic in order to reduce the future earthquake disasters. The seismic microzonation included geoelectric, geoseismic, geotechnic, seismotechtonic, hazard analysis and geotechnical earthquake engineering. Based on seismic results and Standard No. 2800, Bam city can be classified as "Site class I" and " II" .Depth of the seismic bedrock throughout the city approximately is less than 30 m except some portion of central part. The subsurface geotechnical investigation was carried by continuous coring, ten types of soil were identified and their surface and subsurface distributions were mapped. Site response analysis was performed to determine various parameters such as peak acceleration, period corresponding to maximum resonance and coefficient of amplification for various return periods throughout the study area. Results indicated that Bam city can be divided in to four zones with different designed spectra. Some of the design spectra of Bam city were compared with Eurocode and Standard No. 2800.
M. Forouzanfar; H. Abrishami-Moghaddam; M. Dehghani
Abstract
Despite the wide application of SAR images in lineaments extraction, DEM generation and displacements determination, their radiometric quality and interpretability is degraded due to the presence of a multiplicative noise called speckle. Therefore, the enhancement of SAR images is an important step before ...
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Despite the wide application of SAR images in lineaments extraction, DEM generation and displacements determination, their radiometric quality and interpretability is degraded due to the presence of a multiplicative noise called speckle. Therefore, the enhancement of SAR images is an important step before using them in any application. In this paper, a new image enhancement method tailored to SAR images is proposed. In this method, the logarithmically transformed SAR image is decomposed using the dual-tree complex wavelet transform (DTCWT).In order to effectively extract the wavelet interscale dependencies, the signal component of wavelet coefficients is modeled with an isotropic stable distribution, while the noise component is approximated using an isotropic Gaussian model. A bivariate Bayesian estimator is then designed to effectively remove speckle from noisy coefficients in the complex wavelet domain. Both quantitative and qualitative comparisons of the proposed method with new speckle reduction methods, demonstrate its higher performance in speckle reduction from SAR images
Petrology
Nasim Askari; reza Zarei Sahamieh; Jafar Omrani; Mohamad Heshem Emami; C., Vaccaro; J. F. Santos
Abstract
Zarrin Mafic dikes, which outcrop in the Western Yazd block, Central Iran, trending NW–SE, emplaced into the Zarrin granitoid. They are sub-alkaline gabbro; characterized by intergranular and mylonitic foliated texture. Geochemical data reveal the Zarrin mafic dikes are from the partial melting ...
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Zarrin Mafic dikes, which outcrop in the Western Yazd block, Central Iran, trending NW–SE, emplaced into the Zarrin granitoid. They are sub-alkaline gabbro; characterized by intergranular and mylonitic foliated texture. Geochemical data reveal the Zarrin mafic dikes are from the partial melting lithospheric mantle, a spinel-peridotitic source. Furthermore, they are characterized by 87Sr/86Sr ratio of (0.7044-0.7028) and 144Nd/143Nd ratio of (0.5123- 0.5122), that consistent with the derivation from a lithospheric mantle. Their primitive mantle normalized trace elemental patterns display enrichment in LILEs compared to HFSEs, and positive Rb, Ba, and U but negative Ta, Nb, Th, and Zr anomalies, carrying characteristics subduction-related magmatism and metasomatism by subduction-related fluids. The petrogenesis of the Zarrin mafic dikes are related to melting of the lithospheric mantle, and upwelling asthenospheric mantle in the extensional basin which was associated with the subduction.
F. Malekghasemi; V. Simmonds
Abstract
The purpose of this study is to determine the genesis of the manganese occurrences around the Hashtroud city, with special regard to Idahlu- Jokandy region. In this region Mn mineralization is sparse and rather extensive. Mineralization has originated from hot springs and precipitated on the earth surface. ...
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The purpose of this study is to determine the genesis of the manganese occurrences around the Hashtroud city, with special regard to Idahlu- Jokandy region. In this region Mn mineralization is sparse and rather extensive. Mineralization has originated from hot springs and precipitated on the earth surface. The mineralization is mainly massive and vein form. Due to the presence of hot springs and their traces in the study area, it can be concluded that Fe and Mn components were in the hot springs as solution and precipitated on the earth surface or penetrated into existing fractures and faults of the region by the hot springs and consequently caused the mineralization. The main Mn minerals are pyrolusite and psylomelane accompanied by gypsum, travertine, barite and jasper
S.H Ghetmiri; S.M.A Aleyasin
Abstract
Surveying the uptake of metal substances by plants has a very important role in mineral exploration, but biogeochemical exploration has not been paid much attention in Iran. The aim of current study was surveying vegetative species of Khajeh-jamali mineral area to evaluate the probability of biogeochemical ...
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Surveying the uptake of metal substances by plants has a very important role in mineral exploration, but biogeochemical exploration has not been paid much attention in Iran. The aim of current study was surveying vegetative species of Khajeh-jamali mineral area to evaluate the probability of biogeochemical exploration of chromite and to evaluate the uptake of Iron, Copper, Lead and Nickel in the floral plants providing biological absorption coefficient (BAC). Also it aimed to evaluate the reliability of comparing metal uptake of the plants with control groups as an assisting method of exploration. The area is located on the Zagros thrust zone belong to the Alps ophiolitic band. Rock units of this area are mainly composed of rocks from Neyriz ophiolite assemblage, which are mostly of Harzburgite and Dunite types with chromite as the major mineral. The concentrations of metal substances in this area are assessed in previous studies.To study six substances of Chrome, Nickel, Iron, Cupper, Lead, and Zinc, in five herbal species including Amygdalus carduchorum ,Pistacia atlantica, Ebenus stellata, Asragalus sp. and Rheum ribes, twenty five samples (5 from each species) were collected in the study area and five samples (one for each species) were collected from an area outside of the region as control. The samples were analyzed by ICP-OES method. The resultant data was statistically analyzed using One-way Anova and T-test. BAC was in “low” or “very low” range for all the five plant species. The results showed that Rheum Ribes could be useful in Nickle exploration and Ebenus stellata for Lead exploration. This study suggests future biogeochemical investigations of areas with flora having undefined or low BAC to consider comparison of plants’ substance uptake with controls as an assisting method.
R. Shabanian; D. Vachard
Abstract
Carbonate sediments of Permian age crops out in different parts of Iran. based On the foraminiferal content, they are attributed to Bolorian (?) ,Kubergandian to Dorashamian stages.These biogenetic limestone have plenty of Fusulinaceaa, non-fusulinid smaller foraminifers ...
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Carbonate sediments of Permian age crops out in different parts of Iran. based On the foraminiferal content, they are attributed to Bolorian (?) ,Kubergandian to Dorashamian stages.These biogenetic limestone have plenty of Fusulinaceaa, non-fusulinid smaller foraminifers and algae, and they are a basis for determination of age, establishment of biozonation and paleogeography of Permian based on fusulind content. In some localities,chiefly in the north and northwest of Iran because of the distribution of Fusulinid are very rare paleoecological and paleo environmental factors.Despite these situation, smaller foraminifers, especially uniserial ones have a very important role in carbonate sediment make up, determination of age and reconstruction of paleoenvironment.In this paper, this important and crucial role of uniserial foraminifers is discussed.
R Entezari; S.A Alavi; M.R Ghassemi
Abstract
Metamorphic rock assemblage of southern Salmas area is located in the northwestern terminal part of Sanandaj-Sirjan zone, and includes various rock types. This study uses field observations plus mineralogy and petrography of samples to describe and interpret the microstructures in the area. Different ...
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Metamorphic rock assemblage of southern Salmas area is located in the northwestern terminal part of Sanandaj-Sirjan zone, and includes various rock types. This study uses field observations plus mineralogy and petrography of samples to describe and interpret the microstructures in the area. Different rock units are classified into three groups based on their parent rocks, and consist of 1) metabasite, 2) quartz-feldespathic, and 3) marble. Most of these rocks have mylonitic texture but the grade and the intensity of mylonitization are different. Presence of mylonitic foliation and lineation along with other microstructures such as various porphyroclasts, mica fish, S-C fabric, and S-C' fabric demonstrate different mylonitic zones in this area. Due to differences in strain rate, parent rock type, and depth of deformation, we could distinct three mylonitic zones in the metamorphic complex. Most of these mylonitic samples show features characteristic of low to medium grade mylonites, in which mylonitization grade increases from west to east and center of the study area. Presence of ultramylonites in the central part of the area indicates increases in strain rate. Also presence of high-grade mylonites (T> 650 ºC) and migmatite imply that the deformation occurred at depths of middle to lower crust. We could discern two metamorphic phases (M1 and M2) and six deformation phases (D1, D2, D3, D4, D5, D6). Compressional deformation phase D1 occurred after Precambrian magmatism, then a metamorphic phase (M1) impressed these rocks by the Latest Cambrian. During Late Permian to Early Cretaceous, two deformation phases (D1 and D2) with a major simple shear component strongly affected the metamorphic complex, leading to the development of mylonitic zones. Synchronous with the deformation phase D2, a retrograde metamorphic phase (M2) affected the complex. At Late Cretaceous to Early Paleocene, deformation phase (D4) caused obduction of ophiolites over the metamorphic complex. Eventually, two brittle deformation phases (D5 and D6) affected all older rocks.
M Einali; S Alirezaei; R Bakker
Abstract
The Baghkhoshk porphyry copper system is located in the southern part of the Cenozoic Urumieh-Dokhtar magmatic belt of Iran. Mineralization in Baghkhoshk is associated with two shallow diorite-monzodiorite and granodiorite bodies that intruded the older andesitic volcanic rocks. Both intrusions are extensively ...
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The Baghkhoshk porphyry copper system is located in the southern part of the Cenozoic Urumieh-Dokhtar magmatic belt of Iran. Mineralization in Baghkhoshk is associated with two shallow diorite-monzodiorite and granodiorite bodies that intruded the older andesitic volcanic rocks. Both intrusions are extensively altered by hydrothermal fluids into potassic, phyllic, and propylitic assemblages. Mineralization occurs as quartz-sulfide stockworks as well as sulfide disseminations in both intrusions and to a lesser extent in the host volcanic rocks. Two types of quartz veinlets can be distinguished in the Baghkhoshk porphyry system: 1) quartz+ chalcopyrite+ pyrite± molybdenite veinlets (mineralized veinlets); and 2) quartz± pyrite veinlets (barren veinlets). The intrusions display distinct enrichments in large-ion lithophile elements and rare earth elements relative to high-field strength elements and heavy rare earth elements, and distinct Nb, Ta and Ti troughs that are characteristic of subduction-related magmatic arcs. On various diagrams separating tectonic settings, the intrusions plot in the continental arc domain. Three main types of fluid inclusions were identified in quartz from mineralized veinlets: low salinity (4-8 mass% NaCl equivalent), vapor-rich inclusions; high salinity (mainly in the range of 32.5-35 mass% NaCl equivalent), poly-phase inclusions; and low to moderate salinity (mainly in the range of 4-10 mass% NaCl equivalent), liquid-rich inclusions. The vapor-rich inclusions yielded homogenization temperatures ranging between 325 and 434 °C, with a mode at 380-420 °C. Laser Raman microspectroscopic analysis confirmed the presence of CO2 gas and chalcopyrite daughter crystals in the vapor-rich inclusions. The high salinity, poly-phase inclusions were homogenized to liquid at temperatures of mainly 300-375 °C. The liquid-rich inclusions were homogenized at temperatures between 150 and 384 °C, with most of the measurements falling in the range of 200-250 °C and 300-375 °C. The salinities and homogenizaion temparatures for fluid inclusions in quartz from the barren veinlets were found to be 0.5-4 mass% NaCl equivalent and 200-240 °C, respectively. The fluid inclusion data suggest that Cu was originally accommodated into the system by a hot (380-420°C), low salinity (4-8 mass% NaCl equivalent), CO2-bearing, vapor-rich or supercritical fluid. A considerable drop in temperature at constant salinity from vapor-rich to liquid-rich inclusions in the mineralized veinlets suggests that cooling was the main control on ore formation as stockworks and sulfide disseminations. In the later stages of the hydrothermal activity, low salinity, Cu-poor fluids gave rise to abundant barren veinlets consisting essentially of quartz and pyrite.
M. H. Kholghi; M. Vossoughi Abedini
Abstract
Safakhaneh batholith, situated at 47 km southwest of Shahin Dezh, northwest of Iran, is located in the central Iran structural zone intersecting the Cretaceous rocks. The absolute age of the batholith, determined for the first time by K – Ar method, has been calculated ...
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Safakhaneh batholith, situated at 47 km southwest of Shahin Dezh, northwest of Iran, is located in the central Iran structural zone intersecting the Cretaceous rocks. The absolute age of the batholith, determined for the first time by K – Ar method, has been calculated 69.535 Ma. showing upper Cretaceous – Paleocene epoch and Laramide tectonic orogeny. Geochemical investigations of the batholith show that the major part of the batholith is of mantle magma, in which magmatic changes of the crystalline differentiation and contaminations have occurred. The crystalline differentiation has caused the formation of different rock types of quartz monzonite, quartz monzodiorite, tonalite, granodiorite and monzogranite respectively. Primary magma of the rocks is of calc - alkaline and generally metaluminous. The specifications of batholith rocks can be compared with the I – Type Caledonian granites. From the tectonic point of view, the specifications of the batholith can be comparable with the volcanic arc granitoids (VAG).
Sedimentology
Sara Ebrahimi Meymand; Hamed Zand-Moghadam; Mohammad Khanehbad; Asadollah Mahboubi Mahboubi; Gholamreza Hosseinyar
Abstract
Nebkhas are one of the aeolian dunes that play an important role in wind erosion by stabilizing sediments around plants. Due to the depression of northern Shahdad plain (eastern Kerman), the sever wind impact, high rate of sediment supply and the presence of desert plants, nebkhas have expanded. In this ...
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Nebkhas are one of the aeolian dunes that play an important role in wind erosion by stabilizing sediments around plants. Due to the depression of northern Shahdad plain (eastern Kerman), the sever wind impact, high rate of sediment supply and the presence of desert plants, nebkhas have expanded. In this study in order to achieve the formation of nebkha in the Shahdad plain, sedimentological parameters and the effect of vegetation on nebkha geomorphology have been investigated. Due to the expansion of the study area and the different geomorphology of the nebkha, 30 nebkha were sampled along with sediments between them. the analysis of these sediments shows that nebkha sediments are often fine sand sizes that are well-sorted and rounded. However, sediments between nebkha often have a range between gravel (pebble) and fine silt which are subdivided into either surface and sub-surface sediments (depth greater than 2 centimeters). Surface sediments are often coarse grains (granule to coarse sand) and have relatively well roundness and sorting. Field investigations and analyses have shown that genus and plant species are important in the geomorphology of nebkhas in the Shahdad plain but the effect of vegetation on the sedimentary parameters is insignificant. This is due to the fact that the three types of vegetation identified (Tamarix stricta, Seditzia rosmarinus, Prosopis farcta), the highest levels of nebkha is for Tamarix stricta but the sedimentary parameters with different vegetation are not significantly different.
Petrology
Niloofar Nayebi; Dariush Esmaeily; Sourosh Modabberi; Ryuichi Shinjo; Reza Deevsalar; Bernd Lehmann
Abstract
Sr-Nd-Pb isotopes and whole-rock geochemical analyses were carried out on plutonic rocks of the Chadormalu district to constrain the magmatic history of the Cadomian orogeny of the northern Gondwana margin during Late Precambrian–Early Paleozoic times. Despite the similarities in the geochemical ...
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Sr-Nd-Pb isotopes and whole-rock geochemical analyses were carried out on plutonic rocks of the Chadormalu district to constrain the magmatic history of the Cadomian orogeny of the northern Gondwana margin during Late Precambrian–Early Paleozoic times. Despite the similarities in the geochemical data, i.e., calc-alkaline affinity, enrichment in large ion lithophile elements (e.g., Rb, Ba, K, and Cs), and depletion in high field strength elements, e.g., Nb, Ta, P, Ti, and rare earth element patterns, bulk rock Sr-Nd isotope data rull out the co-magmatic nature of investigated basic (gabbro) and felsic (granite) magmas. Sr-Nd isotopic data (e.g., ɛNd(t)= -3.6 to +1.8) along with rather high (207Pb/206Pb)t attest to the crust-dominant, and mantle-derived melts for the granitoids and gabbros, respectively. The investigated zircons yielded the older ages for the gabbroic samples. The extensional tectonic regime is followed by slab retreat or delamination brought flare-up of the oldest arc-related igneous rocks and interacted with Cadomian basement to form the investigated granitoid melts. The gabbroic rocks show geochemical and isotopic disruption and elevation of L-MREE/HREE ratios on the chondrite-normalized rare earth element (REE) patterns; interpreting the evidences of mantle heterogeneity and interaction with Paleoproterozoic basement.
Economic Geology
Shahram Mobaser; Taher Farhadinejad; Abbas Asgari; Mohammad Ali Ali Abadi; Shirin Fatahi
Abstract
The Barzavand copper deposit with Oligocene age located in 30 Km northeast of Zefreh along a tension fault with W-E trend and developed within basaltic lava with stratabound form. Alterations mainly include: pyritization, propylitization, zeolitization, silicification, saussuritization and uralitization ...
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The Barzavand copper deposit with Oligocene age located in 30 Km northeast of Zefreh along a tension fault with W-E trend and developed within basaltic lava with stratabound form. Alterations mainly include: pyritization, propylitization, zeolitization, silicification, saussuritization and uralitization of basaltic lava. Furthermore geochemical studies in Barzavand show enrichment of SiO2, Al2O3, K2O, Na2O, P2O5, TiO2, ∑REE, Ag, As, Ba, Be, Bi, Cd, Cs, Cu, Li, Mo, Nb, Pb, Rb, Sb, Se, Sn, Sr, Ta, Tl, Te, Th, U, W, Y, Zn and Zr, enrichment- depletion of CaO, Fe2O3, MnO, Hf, Sc and V and depletion of S, Ni, Cr, MgO and Co during alteration. The positive correlation between (La/Lu)N, (La/Yb)N, (La/Sm)N and (La/Y)N and CaO (r= 0.70 to 0.96) indicate propylitization of host rock basalt and increase in pH of fluid responsible for mineralization that play important role in differentiation of lanthanides in study area. Ore minerals include chalcopyrite, bornite, covellite, azurite, malachite, hematite, goethite and pyrite. Copper is transported by means of chloride complexes into oxidized brines water related to late diagenesis stage and precipitated by substitution within pyrites formed during the volcanism process. It seems that the Barzavand copper deposit has submarine volcanism, early and late diagenesis, burial metamorphism and weathering stages during its evolution. According to alteration properties, mineralogy and the whole rock geochemistry, the Barzavand copper deposit is most similar to Manto type copper deposits.
N Naimi-ghassabian; M. M Khatib; T Ghasemi rozveh; H Nazari; M.R Heyhat
Abstract
The Boushad shear zone (BSZ) is situated in the south of Birjand with at least 45 km length, about 9.2 Km width and strike N90E. The parts of the ophiolite mélange shear zone south of Birjand have changed by this shear zone. The earliest deformation, a polyphasesynmetamorphic deformation which ...
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The Boushad shear zone (BSZ) is situated in the south of Birjand with at least 45 km length, about 9.2 Km width and strike N90E. The parts of the ophiolite mélange shear zone south of Birjand have changed by this shear zone. The earliest deformation, a polyphasesynmetamorphic deformation which occurred entirely in ductile conditions, D1 and D2 deformation phases are related to this deformation. The D3 deformation affected the area after a period of sedimentation and erosion, Tension gash veins are formed simultaneously. The Strike-slip faults, thrust faults and fault related folds were classified as structures related to the D4 tectonic event, the most recent phase of conflict in the region N055 ±10E is formed. Degree of convergence of the shear zone is R = 0.3, that indicating the formation of a dextral Transpression (Slightly oblique-convergent).
H Jahangir; M Ghobadi Pour; A.R Ashouri
Abstract
The Cambrian- Ordovician boundary strata in the Kalat section, western Koppeh-Dagh, comprise continuous succession of fine clastic sediments, mostly argillites with some shell beds, accumulated offshore. This interval contains analmost complete succession of conodont biozones, including the Cordylodus ...
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The Cambrian- Ordovician boundary strata in the Kalat section, western Koppeh-Dagh, comprise continuous succession of fine clastic sediments, mostly argillites with some shell beds, accumulated offshore. This interval contains analmost complete succession of conodont biozones, including the Cordylodus intermedius, Cordylodus lindstromi and Cordylodus angulatus biozones. The first appearance of the planktonic graptolite Rhabdinopora cf. Flabelliformis flabelliformis (Eichwald, 1840) in black argillite of the upper part of the Cordylodus lindstromi Biozone indicates relatively precise position of the Cambrian- Ordovician boundary in the section. Cambrian- Ordovician boundary beds in the eastern Alborz Region can be subdivided into three lithological units: Furongian bioclastic limestone mainly replaced by fine clastic sediments in the upper part, the terminal Cambrian Cruziana sandstone representing a shoal complex and the Tremadocian grey argillite accumulated offshore. In this area the position of Cambrian- Ordovician boundary is situated somewhat below the base of the Asaphellus inflatus- Dactylocephalus trilobite Biozone.
J Rasouli; M Ghorbani; V Ahadnejad
Abstract
Jebale-Barez granitoid complex is composed of intrusive bodyes included Mijan, Dareh hamzeh, Kerver and Hishin and is located In the southeastern province of Kerman on the lengths of the 57◦ 45 ' east to 58◦ 00' and Northern latitudes 28◦ 30' to 29◦ 00'.The petrologic composition ...
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Jebale-Barez granitoid complex is composed of intrusive bodyes included Mijan, Dareh hamzeh, Kerver and Hishin and is located In the southeastern province of Kerman on the lengths of the 57◦ 45 ' east to 58◦ 00' and Northern latitudes 28◦ 30' to 29◦ 00'.The petrologic composition in intrusive bodyes composed of granodiorite, quartzdiorite, granite and alkali-granite. The geochemical variation diagrams of major oxides, the continuous spectrum of rock compositions has been carried out which indicates the crystallization of magmatic differentiation and extensive appendices. The magma nature of these rocks is sub-alkaline-calc-alkaline, which in SiO2-K2O plot they fall into calc-alkaline series with high potassium. Field observations, petrographic and geochemical studies suggest that the rocks in this area have granitoides I type. Studying the geochemical diagrams of the rocks in the studied area indicates that these rocks have been formed in active continental margin tectononic setting. Most of the volcanic arc granites (VAG) are of "pre-collision" and "syn- collision" types. Three magmatic phases occurred in oligomiocene in this area. The first phase of magmatism in this area composed of the quartzdiorite and diorite that makes the main body of Jebale-Barez granitoid complex. Porphyry bodies will penetrate into the main body, after a short period of magmatic fractionation inside the nest of magma. Petrographic composition of the second phase is mainly diorite to tonalite. Oligo-Miocene magmatic final phase (Phase III) occurs in the region after a short time that the lithological composition of the granite to alkali granite. The third group of rocks in the study area from the main body mother came from magma fractionation. based on the location of Urmia-Dokhtar magmatic belt seems the rocks of this region there came to subducted oceanic crust Neotethyan beneath continental crust of central Iran.
T Naderi; A ShafieiBafti; M Shahpasand-zadeh
Abstract
Structural data from the Kuh-Banan oblique-slip fault system show that this active fault controls the structural architecture of the Tikdar-Goorchoieh area, north of Kerman. The Kuh Banan fault system is consisted ...
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Structural data from the Kuh-Banan oblique-slip fault system show that this active fault controls the structural architecture of the Tikdar-Goorchoieh area, north of Kerman. The Kuh Banan fault system is consisted of three fault branches with mean trend of N70E in the north of the Tikdar - Goorchoieh village. These fault branches with a dip of 50-70 toward the northwest and slip rake of 50-80 N indicate the prevalent reverse with right-lateral strike-slip motion of the fault. The main strand of Kuh-Banan fault system with a northwest-southeast strike is reported between the Dehsu rock series and Shemshak Formation whereas the fault branches with a northeast-southwest trend are situated between the Hojedk Formation and Neogene alluviual deposits and Quatrnery sediments. In this area, the Dehsu rock series (Late Neo-Proterozoic-Lower Cambrian) is composed of dolostone and evaporitic rocks which thrusted over the sandstones, shales and limestones of the Hojdak Formation (Jurassic). According to the structural evolution of the Kuh-Banan fault system in the study area, the first fault branch (F3) with three fault slip motion in the northeast-southwest direction has developed between the Shemshak Formation and Dehsu rock series in north of Tikdar. The later fault branches of F1, F2, and F4 with the same trend have propagated from the main fault and developed between the Dehsu rock series with the Hodjek, Shemshak and Dahu (equivalent of Lalun) Formations.
J Sharifi; M.R Nikudel
Abstract
By fast growing of structures and need for aggregates materials, more quarry resources should be provided and rapid identification and exploration of these resources should be introduced. Because of the importance of engineering geology parameters in exploration of aggregate quarries sources, based to ...
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By fast growing of structures and need for aggregates materials, more quarry resources should be provided and rapid identification and exploration of these resources should be introduced. Because of the importance of engineering geology parameters in exploration of aggregate quarries sources, based to in-situ and laboratory studies in this research, the parameters and criteria were determined and the results are presented as a simple applicable criterion. For this purpose, first site investigation was carried out and then samples and specimens from different selected mines were taken. Laboratory tests were carried out in accordance with relevant standards, and finally concrete samples were prepared using these materials. The results of tests on aggregates and concrete have been analyzed, and parameters involved in the quality of the concrete were classified and presented as a criterion. According to accuracy and ease application of this criterion, it is applicable for selecting the materials with minimum experiments, the desirable mines identification and an estimate of the ultimate strength of concrete will be provided for the engineers. The criteria according to type and kinds of the samples, is applicable with a broad scope in different geographical areas.
N Hashemi; A.R Ashouri; M Aliabadian; M.H Mahmoudi Gharaie
Abstract
Paleozoology of Yafteh and Kani Mikaiel caves in center and northwest of Zagros Mountains led to the identification of small mammals' assemblage. Taxonomic determination revealed inclusion of four orders of small mammals including: order Rodentia with families of Muridea, Cricetidae, Calomyscidae, ...
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Paleozoology of Yafteh and Kani Mikaiel caves in center and northwest of Zagros Mountains led to the identification of small mammals' assemblage. Taxonomic determination revealed inclusion of four orders of small mammals including: order Rodentia with families of Muridea, Cricetidae, Calomyscidae, Dipodidae; order Lagomorpha with two families of Ochotonidae and Leporidae; order Soricomorpha with family Talpidae, and order Carnivores with family Mustelidae. These remains were recovered after systematic excavation in these caves. Radiocarbon analysis of these remains showed the oldest sample belonged to Yafteh cave with 35,000 BP. and Pleistocene period, whereas, Kani Mikaiel cave covered the periods from lat Pleistocene (19,000 BP.) to Holocene (17, 00 BP.). Geochronology analysis of Kani Mikaiel sediments showed that the lower layers of this cave belonged to the last glacial age in Pleistocene which gradually has been replaced by the warm weather in Holocene period. With continuing of this weathering varying, faunal spectrum of Pleistocene and Holocene periods has been migrated in cold and warm phases or more spread. The aim of this research, are the study of small mammal remains of Yafteh and Kani Mikaiel caves in center and northwest of Zagros mountains and the research about the study of paleobiodiversity, paleoenvironment conditions and the evolution of microvertebrate on the Iranian plateau.
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.
