Original Research Paper
Petrology
Zahra Alaminia; Zahra Rahmati; Hossein Azizi
Abstract
The Dorojin granitoid at the northeastern Isfahan is located in the central Urumieh-Dokhtar zone and within the volcano-sedimentary complex. The Dorojin iron deposit is the one of the several ore deposits that Dorojin granitoid body is caused in its surrounding rocks. According to microscopic evidences, ...
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The Dorojin granitoid at the northeastern Isfahan is located in the central Urumieh-Dokhtar zone and within the volcano-sedimentary complex. The Dorojin iron deposit is the one of the several ore deposits that Dorojin granitoid body is caused in its surrounding rocks. According to microscopic evidences, mineral assemblage of wollastonite, garnet, pyroxene (diopside), amphibole, epidote, feldspar, calcite and quartz, Dorojin deposit attributed to the class of calcic skarns that occur during two stages progressive and regressive. Based on electron microprobe analysis, some garnets are andradite (An92-97Gr1-5) in core and andradite-grossular (An53-66Gr30-41Sp2-4) in rim. In the beginning, andradite fluid inclusions with temperature range from 369˚ to 444˚C and salinity range from 11.22 to 12.96 wt.% NaCl eqv., originate from magmatic fluids, while with change in the acidity condition of environment and the opening of system, grandite, epidote and calcite fluids with a temperature between 221˚ and 305˚C and salinity between 0.4 and 10.11 wt.% NaCl eqv., are dominated by mixing and dilution of early magmatic fluids with meteorite waters. Sr isotopic ratio of garnet vary between 0.70760 and 0.70805, suggesting that prominent role of the magmatic fluids for the formation of andraditic garnet.
Original Research Paper
Stratigraphy and Palaeontology
faeze Amiri; E Zarei
Abstract
The Gurpi formation in Bishe-deraz Section, south of Ilam, consists of 201m marl with intercalations of limy marl with two formal members of Seymareh (Lopha) and Emam-Hasan. The formation overlies the Ilam Formation and is gradationally overlain by the purple shales of the basal part of the Pabdeh Formation. ...
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The Gurpi formation in Bishe-deraz Section, south of Ilam, consists of 201m marl with intercalations of limy marl with two formal members of Seymareh (Lopha) and Emam-Hasan. The formation overlies the Ilam Formation and is gradationally overlain by the purple shales of the basal part of the Pabdeh Formation. The Gurpi Formation was divided to 9 biozone on the basis of planktonic foraminifera which almost are cosmopolitan and consist of: 1- Radotruncana calcarata Taxon-Range Zone. 2- Globotruncanita stuartiformis Partial-Range Zone. 3- Globotruncana aegyptiaca Interval Zone. 4-Gansserina gansseri Interval Zone. 5- Contusotruncana contusa Interval Zone. 6- Abathomphalus mayaroensis Interval Zone. 7- Praemurica uncinata Interval Zone. 8- Morozovella angulata Interval Zone. 9- Globanomalina pseudomenardii Interval Zone. The formation was deposited from upper Campanian through late Paleocene (Selandian-Thanetian?) according to the planktonic foraminifera recorded. A distinct hiatus was confirmed at the Cretaceous-Paleogene boundary according to microbiostratigraphic and sedimentologic studies and also field work observation.
Original Research Paper
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.
Original Research Paper
Petrology
Maryam Dorani; Mohsen Arvin; Roland Oberhänsli; Hadi Omrani; Sara Dargahi
Abstract
Bajgan Complex is a part of Iranian Makran including many kinds of metapelites, metabasites, calcsilicates, amphibolites, marbles, meta volcanosediments, felsic, mafic and ultramafic intrusives. The calcsilicates are divided into amphibole bearing epidote schist, epidote - amphibole schist, epidote – ...
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Bajgan Complex is a part of Iranian Makran including many kinds of metapelites, metabasites, calcsilicates, amphibolites, marbles, meta volcanosediments, felsic, mafic and ultramafic intrusives. The calcsilicates are divided into amphibole bearing epidote schist, epidote - amphibole schist, epidote – amphibole - garnet schist and carbonate bearing mica schist. Among of all calc silicates the epidote – amphibole - garnet schist shows the highest metamorphic condition and consists of garnet, amphibole, epidote, calcite, quartz, secondary chlorite and minor amount of titanite, apatite, white mica and magnetite. In this study the mineral chemical compositions, temprature, pressure and fluid activity in different metamorphic stages of epidote – amphibole - garnet schist were detected. In according to chemical data, garnet has almandine, grossular, spessartine and pyrope solid solution (Alm 35-50, Grs 23-31, Sps 14.6-36, Prp < sub> 2.6-9.8 ; mol%) and shows chemical zoning as almandine and spessartine have an increasing and decreasing trend, respectively, from core to rim. Amphiboles are classified in sodic- calcic group and are Barroisite. Chlorites are kown as Ripidolite and epidotes are classified in Clinozoisite subgroup. Peak metamorphic condition of epidote – amphibole - garnet schist has been estimated about 610° C and 8 kbar and molar fraction of Co2 and H2O have been calculated about 0.32 and 0.68, respectively. The retrograde metamorphic condition are about 525° C, 4.5 kbar and molar fraction of Co2 and H2O have been calculated about 0.31 and 0.69, respectively. The epidote – amphibole - garnet schist followed a ‘clockwise’ P–T path during prograde and retrograde metamorphism.
Original Research Paper
Stratigraphy and Palaeontology
Azam Mahanipour; Maryam Eftekhari; Soheila Soheili
Abstract
In order to study the early Aptian Oceanic Anoxic Event 1a (OAE 1a), calcareous nannofossils are investigated at the late Barremian ‒ early Aptian sediments of the Garau Formation at south west of the Kabir-Kuh anticline, Qaleh-Darreh section. Ninety species of calcareous nannofossils from 43 genus ...
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In order to study the early Aptian Oceanic Anoxic Event 1a (OAE 1a), calcareous nannofossils are investigated at the late Barremian ‒ early Aptian sediments of the Garau Formation at south west of the Kabir-Kuh anticline, Qaleh-Darreh section. Ninety species of calcareous nannofossils from 43 genus and 15 families are identified along with marker species like Hayesites irregularis and Eprolithus floralis. Based on index calcareous nannofossil taxa, the studied interval is located between the uppermost part of the CC6/NC5 and the early part of CC7/NC7A. The first occurrence of H. irregularis, the marker of the Barremian ‒ Aptian boundary, used as an index species between CC6/NC5E and CC7/NC6. Statistical analysis of the calcareous nannofossil assemblages at the studied interval indicate the presence of nannoconid decline at the Barremian ‒ Aptian boundary and early Aptian and nannoconid crisis at CC7a/NC6B biozone. Nannoconid crisis is one of the main markers of the early Aptian OAE 1a that is recorded from different parts of the world at the Tethys and Boreal realms, Atlantic and Pacific oceans at the early Aptian (NC6 biozone). At the current study the early Aptian OAE 1a is recorded from the Garau Formation based on calcareous nannofossil assemblages.
Original Research Paper
Economic Geology
faraj fardoost; Akbar Abdollahi Hydarbaghi; Solmaz Baluchi
Abstract
The Robaei Iron deposit is located in 96km south of Damghan. Host rocks of deposit are Late Cretaceous limestones (part I) and Eocene volcano- sedimentary rocks including sandy tuff (part II.( The alterations include chloritization, epidotization, argillation, silicification, carbonatization and hematitization. ...
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The Robaei Iron deposit is located in 96km south of Damghan. Host rocks of deposit are Late Cretaceous limestones (part I) and Eocene volcano- sedimentary rocks including sandy tuff (part II.( The alterations include chloritization, epidotization, argillation, silicification, carbonatization and hematitization. Minerals forming can be divided into three groups; iron minerals (hematite, magnetite, pyrite, pyrrotite goethite and limonite), copper- minerals (chalcopyrite, chalcocite, covellite and malachite) and gangue minerals (calcite, dolomite, quartz, garnet, epidote and chlorite). The structure and textures of ore minerals are massive, vein- veinlet, open space filling and disseminated. In part I, the metals grade of Fet is about 60%, Cu 0.7 % and Au 2.7 ppm and in the part II, the Fet are variables between 5.88 to 82.91% (average 31.2%), Cu between 275 to 20761 ppm and Au 0.89 ppm. Fluid inclusion studies were carried out on quartz mineral from the part II that homogenization temperature is frequency variables between 200 to 249°C with salinity of 2-4% wt. %NaCl. Based on the results of this investigation, part I has similarities with calcic skarn of low temperature and part II showed more similarities with iron oxide- copper- gold (IOCG) deposits.
Original Research Paper
Sedimentology
Umid Kakemem; Mohammad Adabi; Ehsan Dehyadegari
Abstract
Depositional texture, sedimentary structure and present fauna led to characterize twelve carbonate- evaporate facies. These facies were classified in three facies belts including tidal flat, lagoon and shoal. Developpment of tidal zones together with evaporate deposits and thrombolite facies (signs to ...
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Depositional texture, sedimentary structure and present fauna led to characterize twelve carbonate- evaporate facies. These facies were classified in three facies belts including tidal flat, lagoon and shoal. Developpment of tidal zones together with evaporate deposits and thrombolite facies (signs to a shallow depositional environment), the absence of continuous reef‐frame builders, high production of carbonate mud, absents of calciturbidite, tempestites deposits and slump structures are evidences for a homoclinal carbonate ramp setting. The facies based on petrophysical characteristics which is the results of depositional texture and diagenesis are classified in seven reservoir rock types. In which, the first rock type (RT1) has weak reservoir property and toward RT7 reservoir quality will increase. Facies variation related to sea level fluctuations led to subdivide the whole strata into two 3rd order sequences. Facies stacking patterns in the sequences characterized by subtidal facies (lagoon and shoal) tend to have the most reservoir quality that covered by evaporative (Mf1) and peritidal facies (Mf2 to Mf4) with low-reservoir quality. The most reservoir quality in both K1 and K2 reservoir zones is coincident with late TST, maximum flooding surface (mfs) and late HST in identified depositional sequences which is settled in high-energy shoal facies intervals.
Original Research Paper
Petrology
Elahe Namnabat; Mansour Ghorbani; Seyed hassan Tabatabaei
Abstract
The Youseflo pluton, a part of Ahar - Arasbaran magmatic belt, is located in south east of Ahar city in north east of East Azarbayejan province of Iran. The pluton is mainly composed of quartz monzonite, granodiorite and granite, however, the major investigated rock is granodioritic in composition. Quartz, ...
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The Youseflo pluton, a part of Ahar - Arasbaran magmatic belt, is located in south east of Ahar city in north east of East Azarbayejan province of Iran. The pluton is mainly composed of quartz monzonite, granodiorite and granite, however, the major investigated rock is granodioritic in composition. Quartz, Plagioclase, biotite, amphibole, K-feldspar, chlorite, zircon, sphene, apatite and opaque minerals are the minerals of these rocks. Biotites, as a significant ferromagnesian mineral in Youseflo pluton, are Mg- rich, Cl-poor where all are primary types. Considering Fe/(Fe+Mg) (from 0.36 to 0.43) and Al IV (average 2.32 apfu), minerals are classified as biotite between Annite- siderophyllit endmembers. The study of mineral chemistry of biotites demonstrates that the calculated pressure based on total Al content in biotites varies from 0.19 to 0.89 kb which is indicative of a shallow emplacement depth. Crystallization temperature of biotites based on Ti content and Ti/Fe+2 ratio suggests an average temperature of 735 oC.
Original Research Paper
Hydrology
Asghar Asgharai Moghaddam; Ata Allah Nadiri; Faiba Sadeghi Aghdam
Abstract
Naqadeh plain located in the southwestern part of Urmia Lake has suitable water resources. In recent years, agricultural development and increasing industrial units, in addition to inadequate disposal of urban, industrial and agricultural wastewater to the Gedar River, increase the risk of groundwater ...
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Naqadeh plain located in the southwestern part of Urmia Lake has suitable water resources. In recent years, agricultural development and increasing industrial units, in addition to inadequate disposal of urban, industrial and agricultural wastewater to the Gedar River, increase the risk of groundwater contamination. In order to monitor the groundwater resources of this plain, 33 water samples from exploitation wells were collected during July 2016. Hydrochemical parameters and the concentration of the major, minor and heavy metals elements of collected samples were analyzed. In order to identify the origin of heavy metals and the related geogenic and anthropogenic pollution sources of them, hydrochemical diagrams, statistical analysis, spatial distribution maps and geological interpretations were used. The results indicate the concentration of some parameters including EC, and heavy metals include, Fe, Mn, and Al are higher than the international standard limits. HPI was used to understand the drinking quality of groundwater resources in regard to the concentrations of six heavy metals. Classification results show a good quality for 70% and inadequate quality for 30% of the samples. The total HPI index of Naqadeh plain is 23.24, which is lower than its critical values(100). Also, the highest HPI of sampling points with values of 161,220 and 871 threaten human health. High concentrations of heavy metals can be related to the dissolution of geological formations, mining of iron ore, and the activity of industrial units and the condensation of elements in groundwater due to high evaporation in areas with a low depth of groundwater.
Original Research Paper
Economic Geology
Amir Pakizeh; Fardin mousivand; Abdorrahman Rajabi; Sajjad Maghfouri
Abstract
The Nohkuhi copper deposit located at 40 Km Northwest of Kerman, occurred in the Central Iran structural zone (Bafq- Posht-e- Badam block), within Late Precambrian-Early Cambrian volcano-sedimentary sequences. Host sequence of mineralization consists of dominantly black shale, sandstone and dacitic lava ...
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The Nohkuhi copper deposit located at 40 Km Northwest of Kerman, occurred in the Central Iran structural zone (Bafq- Posht-e- Badam block), within Late Precambrian-Early Cambrian volcano-sedimentary sequences. Host sequence of mineralization consists of dominantly black shale, sandstone and dacitic lava of Rizu Series. Mineralization occurred as stratabound (vein-veinlets) and stratiform (bedded) in the three copper- and two iron-manganese horizons. The mineralization in the Nohkuhi area involves four ore facieses including stringer, vent complex, bedded, and hydrothermal-exhalative banded iron and manganese-rich sediments. This mineralization contains primary pyrite, chalcopyrite, sphalerite, hematite and pyrolusite. Wallrock alterations are dominated by chloritic and carbonatic-sericitic- silicic. Metal zonation was observed in the deposit. Based on characteristics of mineralization, such as tectonic setting, host rocks, ore textures and structures, mineralogy, metal and alteration zonation, and comparison with main characters of the volcanogenic massive sulfide (VMS) deposits, the mineralization shows most similarities with the siliciclastic felsic or Bathurst- type deposits.
Original Research Paper
Sedimentology
Sh. Erfan; K. Rezaei; R. Lak; S. M. Ale Ali
Abstract
Lake Urmia is the greatest hayper salin Lake in the world. This Lake, located in Azerbaijan area, Northwest of Iran is an intra-continental sedimentary basin. Its area is about 6000 km2 with an average water depth of 6 meter. Evaluation of past climate change in Lake Urmia, according to Clay Minerals, ...
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Lake Urmia is the greatest hayper salin Lake in the world. This Lake, located in Azerbaijan area, Northwest of Iran is an intra-continental sedimentary basin. Its area is about 6000 km2 with an average water depth of 6 meter. Evaluation of past climate change in Lake Urmia, according to Clay Minerals, is the main subject for current study. For mineralogical and sedimentological investigations 18 sediment cores were collected from the east and west of Urmia lake. 96 samples from 18 sediment cores in transect to the center of lake were collected and studied by X-ray diffraction (XRD) technique. The clay minerals include Kaolinite, Illite and Montmorillonite. Kaolinite and Illite are the most important clay minerals in the Coastal plain of urmia lake. Origins of clay minerals in the Coastal plain of urmia lake are generally detrital, occurred by physical weathering and indicate composition of bed rock. The study of surface sediments indicates that amount of clay minerals from margin to center of the lake such as another detrital mineral (Quartz) is decreased. In addition, amount of them towards depth is increased. Therefore, it shows the presence of a high water level and cold - humid climate in the past (late Pleistocene).
Original Research Paper
Petrology
Abdolsamad pourmohammad; Ahmad Ahmadi khalaji; Masoud Homam; Zahra Tahmasbi; Mohammad Ebrahimi
Abstract
Geysour area is located in the east of Gonabad city and is part of the north of the Lut Block. The rocks in this area include granitoid rocks and high temperature – low pressure metamorphic rocks. Granitoid rocks are composed of granodiorite, enclave (metamorphic and igneous) and microgranites. ...
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Geysour area is located in the east of Gonabad city and is part of the north of the Lut Block. The rocks in this area include granitoid rocks and high temperature – low pressure metamorphic rocks. Granitoid rocks are composed of granodiorite, enclave (metamorphic and igneous) and microgranites. These rocks belong to medium to high potassium calc-alkaline series, low temperature I type granite and are poorly peraluminous. The Chondrite-normalized REE patterns show that the rocks are enriched incompatible elements, with negative anomalies in Nb, Ta, Sr, P, Ti and Ba and strong enrichment in Rb, K and Th. These patterns are in perfect harmony in granodiorite, microgranular enclave (MME) and microgranite specimens. This harmony also has in upper, middle continental crust and greywackes. Positive anomalies in Rb, Th, Sm and negative anomalies in Ba are prominent in the composition of the crust. Based on the integration of these patterns with the pattern of upper continental crust (UCC) elements and greywackes and adaptation to laboratory work, the Geysour granitoid originated from crustal materials and a little mantle component. The temperature of granitoid formation was estimated based on the Zircon saturation temperature of 748-790 ֯C. Microgranular enclaves have rounded and oval shapes, mixed areole around them, fine grained texture, quartz and plagioclase eyes, bladed biotite, needled apatite, oxide phases in biotite, and the presence of a simple mixed – hyperbolic curve between MME and granodiorite. Field, petrography and geochemistry of the major and rare earth elements data suggest mixing/ mingling (partial melting) processes for the origin of enclaves and the rare earth elements patterns indicates the relationship between Geysour granitoid with the subduction system. Analysing its data, based on logarithmic ratios, show collision tectonic environment. Also, the tectonic-chemical distinctive diagrams suggest a syn-collision to post-collision tectonic type that is interpreted in connection with the collision of the Afghan Block with the Lut Block.
Original Research Paper
Exploration and Mining
Yaghoob Zarei; Ali Uromeihy; MohammadReza Nikoodel
Abstract
In this labratory study, the effect of joint density (number and spacing) on the pressure wave velocity was researched in pyroclastic rocks. After determining the physical properties, the P-wave velocities of intact rock samples were measrued. Then, an artificial joint perpendicular to the measuring ...
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In this labratory study, the effect of joint density (number and spacing) on the pressure wave velocity was researched in pyroclastic rocks. After determining the physical properties, the P-wave velocities of intact rock samples were measrued. Then, an artificial joint perpendicular to the measuring direction was created in each sample, and the wave velocity tests were repeated. These tests were continued up to 5 joints with two sets of 2 and 5 cm spacing. Consequently, the data were analyzed using the statistical methods. The results show that the P-wave velocity was decreased by increasing the number of joints in both spacing sets, and thus an inverse linear relationship was obtained. However, as the number of joints increases, the reduction rates of wave velocity were different at two spacing sets. More precisely, up to 3 joints, the reduction rate in the 5 cm spacing set was more than that in the other set. Nonetheles, after the third joint, the decreasing rate in the 2 cm spacing set became greater. Generally, the shorter spacing had a more reduction (attenuation) in the P-wave velocity. In this regard, at a total of 5 joints, the reduction rate of the P-wave velocity in 2 cm spacing set was more than that in the other set.
Original Research Paper
Economic Geology
Sahar Tarabi; Mohamad Hashem Emami; Sourosh Modaberi; Seyed Jamal Shaykh Zakariaee
Abstract
Momen-abad area, in the southeast of Birjand and the northeast of Sarbisheh, is located in the Sistan-Zemestan zone. Based on the field studies, petrography, geochemical (XRF) and X-ray diffraction (XRD) in two volcanic sequences, the alteration conditions in the area have been investigated. According ...
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Momen-abad area, in the southeast of Birjand and the northeast of Sarbisheh, is located in the Sistan-Zemestan zone. Based on the field studies, petrography, geochemical (XRF) and X-ray diffraction (XRD) in two volcanic sequences, the alteration conditions in the area have been investigated. According to mineralogy and chemical studies, bentonites are sodium-calcium and heterogeneous. Mineralogy findings indicate that smectite minerals, cristobalite and quartz, alkaline feldspars (albite and anorthite and sanidine), gypsum, calcite, hematite, holandite, klinoptiolite, kaolinite, ileite, and halite minerals form bentonites. In the first sequence, the effects of argillic and iron oxide alterations and in the second sequence, the effects of alteration of argillic, carbonate, chlorite, calcite, albite, silicification and iron oxide are found. Altered units which are related to the second sequence in four layers include Rhyolytic perlites of the vein, masses, lenses; white bentonites and green; Rhyodacite and dacite with the effects of alteration of devitrification, and the alteration of perlite to bentonite, advanced argillic and silicification. In addition, the composition textures of lava-pyroclastic, devitrification and the alteration of perlite to bentonite due to diagenetic alteration are found out. Glass argillization and feldspars in volcanic units, and the alteration of plagioclase to albite + sericit, biotite to chlorite, stone to quartz, calcite, zeolite and chlorite in perlites, iron oxide veins and red unit are found out in the sequences. Moreover, the change color of bentonite in the region related to alteration hydrothermal, and the presence of fluids and iron-magnesium-rich solutions are obvious in these sequences.
Original Research Paper
Economic Geology
Hasan Feizi; Sohelia Aslani; Farhang Aliyari; Abbas Bahroudi; Abdolhamid Sartipi
Abstract
The Khanik-Ghazan Titanium ore deposit is located at 82 km northwest of Urmia, northern Sanandaj-Sirjan zone. The main objective of this research is to identify potentially mineralized areas and to prepare a mineral prospectivity map in the Khanik-Ghazan deposit applying the Fuzzy Inference System (FIS). ...
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The Khanik-Ghazan Titanium ore deposit is located at 82 km northwest of Urmia, northern Sanandaj-Sirjan zone. The main objective of this research is to identify potentially mineralized areas and to prepare a mineral prospectivity map in the Khanik-Ghazan deposit applying the Fuzzy Inference System (FIS). After preparing the facto maps, the main stages of the investigation comprise the preparation of fuzzy factor maps using the appropriate linguistic variables and proper membership functions, combining factor maps using the fuzzy inference (by creating a fuzzy database of If-OR rules), identification of susceptible areas, and the generation of a potential mineral map using the output closure. In this study, in order to control the accuracy of the data, we tried to apply two new integrated methods including the fuzzy logic and hierarchical analysis processes. The results obtained from these methods was confirmed and complemented by each other and demonstrated highly potential mineralized zones. This statement is validated by several investigation methods including the field surveys and evidence of 80 samples collected from rock outcrops. Based on obtained results and modelling of geophysical data, the central part of the study area was recognized for further exploration using the drillcore subsurface exploration.
Original Research Paper
Stratigraphy and Palaeontology
k. Khaksar
Abstract
This research has described for determinate of Oligo-Miocene Foraminifers at the Do Baradar section. The main aim project was scrutiny age of this Formation and Paleoecology distribution lot of basins have created with big streams between Zagros and Alborz with Central Iran. Final transgressive sea on ...
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This research has described for determinate of Oligo-Miocene Foraminifers at the Do Baradar section. The main aim project was scrutiny age of this Formation and Paleoecology distribution lot of basins have created with big streams between Zagros and Alborz with Central Iran. Final transgressive sea on the Rupelian to Late Miocene have created the continue sediments consist low depth Lime stone and Marls. These sediments have complete different colors and lithology have named Lower Red Formation and Upper Red Formation and total Qom Formation. In this section the thickness of Qom Formation is 830 Meters that 8 units can separate of Marls and Limestone. From the Limestone have collected a lot of Samples and on Marls have samples isolate Foraminifers. The result of this research have been showing: The Central Iran Sediments on the Rupelian to Burdigalian have a warm climate (Tropical) to sub warm (Subtropical) climate with restrict marine environment but continue to open sea. The depth on Oligo-Miocene was different and have swing.
Original Research Paper
Tectonics
Rojin Hamidi; mohamad reza ghassemi; mohammadreza sheikholeslami
Abstract
Continuation of the compressional regime within the convergence zone between the Central Iran and Turan rigid blocks caused thrusting of old rock complexes over the recent sediments. As a result of multiple thrusts and folds, the area uplifted at the same time and the Binalud range have been shortened. ...
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Continuation of the compressional regime within the convergence zone between the Central Iran and Turan rigid blocks caused thrusting of old rock complexes over the recent sediments. As a result of multiple thrusts and folds, the area uplifted at the same time and the Binalud range have been shortened. This study attempts to evaluate the amount of shortening of the Binalud mountains by reconstruction of a balanced cross-section. Field data from the Dulat-Abad-Neyshbur transect, study of the geological units and décollements along the section, and the Move® software environment are used as the basis for this research. Based on these information, four tests were carried out for balancing the cross section in question. The first test, which used the arc and polygon method for the horizons and a listric fault without floor thrust, failed to display the deformed section. In the second test the section was drawn, however the deformed structure did not balance the section in the process of unfolding the fault bend folds. In the third and fourth tests, we used the kink method to restore the deformed state to an undeformed section. For the third test, deformation was proceeded from the hinterland, and in the process of restoration, a shortening of about 65% was revealed. The fourth test was proceeded from the foreland, and taking into account both the foreland uplifts and shortening, the amount of shortening of Binalud range was estimated to about 26%. The final structural model defined a thin-skinned fold and thrust belt which included fault-bend-folds with out-of-sequence and in sequence duplexes. Major décollement horizons defined in the region include: 1) shale horizons within the Silurian-Devonian rock units, 2) medium-bedded dolomite and limestone layers within the Bahram Formation, and 3) evaporitic layers in the Eocene sediments.
Original Research Paper
Economic Geology
Amir Naderi; Ghasem Nabatian; Maryam Honarmand; Hossein Kouhestani
Abstract
Halab manganese deposit is located in the Sanandaj- sirjan zone, 100 km southwest of Zanjan. The rock units in the study area include Precambrian Kahar and Jangoutaran marble Formations. Manganese mineralization in the Halab area, occurred as veins and massive in the Jangoutaran marble and minor amount ...
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Halab manganese deposit is located in the Sanandaj- sirjan zone, 100 km southwest of Zanjan. The rock units in the study area include Precambrian Kahar and Jangoutaran marble Formations. Manganese mineralization in the Halab area, occurred as veins and massive in the Jangoutaran marble and minor amount in the schist unit. The main important minerals in the Halab manganese mineralization consist of pyrolusite, psilomelane, manganite and goethite, which calcite and quartz occurred as associated gangue minerals. The ore textures include cloform, vein-veinlets, massive, comb, dogtooth, botryoidal, replacement and relict. Actinolite, carbonate and silicic are the main important alterations in this area. Primitive mantle normalized of the rare earth elements (REE) patterns in the orebody and hydrothermal carbonate samples show that the samples relatively enrichmed in light REE. The analyzed samples show significant negative anomaly in Ce and weak negative anomalies in Eu. Furthermore, the primitive mantle normalized pattern of trace elements in the orebody and hydrothermal carbonate show significant enrichment in Ba, U, La, Pb, Sr and negative anomaly in Rb, Th, Nb, Ce, P, Zr and Ti. The field and microscopic studies as well geochemical evidences suggest that the mineralization formed by hydrothermal fluids. The circulation of meteoric and/or magmatic fluids within the Precambrian units provide the important elements such as Mn, Fe and Ca for mineralization. When the mineralizing fluid contact with reactable rocks, caused the formation of Mn mineralization in the Halab area.
Original Research Paper
Petrology
Hamid Ahmadipour; Hamideh Salehinejad; Seyed Hesam-Aldin Moeinzadeh; Abbas Moradian
Abstract
Shan Abad–Raviz basic intrusions from the West of Rafsanjan (Kerman province), represent a part of Dehaj-Sarduyieh belt and intruded into the Eocene volcano-sedimentary rocks as dykes and apophyses. Thicknesses of the dikes and the diameters of the patches reach up to 4 and 10 meters respectively. ...
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Shan Abad–Raviz basic intrusions from the West of Rafsanjan (Kerman province), represent a part of Dehaj-Sarduyieh belt and intruded into the Eocene volcano-sedimentary rocks as dykes and apophyses. Thicknesses of the dikes and the diameters of the patches reach up to 4 and 10 meters respectively. In the field, they appear as dark intrusions contain sporadic euhedral pyroxene crystals with up to 5 mm in size. They are gabbro and diorite and their main minerals are plagioclase and pyroxenes set in a fine-grained matrix and show intergranular and porphyroid textures. These rocks have low-K calc-alkaline affinities and their geochemical characteristics tend to the subduction zone settings. In these rocks, 87Sr/86Sr and 143Nd/144Nd ratios vary between 0.70403 to 0.70409 and 0.5128 to 0.5129 respectively and εNd(i) values change between 3.52 to 6.6. These evidences along with the special textures show that their parent magmas affected by fractionation, assimilation and magma mixing processes. Considering that these rocks have intruded into the Eocene volcanics, we suggest that they represent the last stages of Eocene magmatism in the Cenozoic Kerman magmatic belt and intruded into the crust after the intiation of Neo-Tethys subduction beneath to Central Iranian block, probably in a continental margin tectonic setting.
Original Research Paper
Tectonics
Tahmoores Yousefi; Kouros Yazdjerdi; Manouchehr Ghorashi; Alireza Shahidi
Abstract
The current form of the folded Zagros is the result of the oblique collision the Arabian and Iranian plates in Late Cenozoic. In this study, Cenozoic stress field changes in Zagros Simply folded belt and structural evolution after collision in Shiraz Area have been evaluated. The geological formations ...
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The current form of the folded Zagros is the result of the oblique collision the Arabian and Iranian plates in Late Cenozoic. In this study, Cenozoic stress field changes in Zagros Simply folded belt and structural evolution after collision in Shiraz Area have been evaluated. The geological formations under investigation are from Late Cretaceous to Neogene (Late Cenozoic). In this regard, geometry and kinematics of the faults, stylolites and other tectonic and stratigraphic evidence in geological formations outcrops in the study area at 30 stations were taken. The tension main axes (σ1, σ2, σ3) were calculated by Inversion Method for the categorized data. The results of the reconstruction of the paleo stress show compressional and Strike- Slip tectonic regime in Cenozoic. Moreover, anticlockwise rotation of the direction of compressive stress over time is about 60 degrees. As pre-folding compressional stress direction (σ1) is about N60E and its time is Miocene and before that. Whereas syn-folding stress direction is N35E and its age is equivalent to Pliocene that is the same age as old Bakhtiary formation. Stress changes in post-folding indicate N20E and its age equivalent to Pleistocene that is the same age as young Bakhtiary formation. At the present time, the maximum stress direction that is about N-S affects the area.
Original Research Paper
Geological Environment and Engineering
Ali Alavi Naeini; Bahram MalekMohammadi
Abstract
. In this study , At first, meteorological data was reviewed between 1993 and 2018. Then, using LARS-WG software, climate change modeling was compared with the output data from climate change modeling in the period 2046-2065. Considering the changes in modeling in the LARS-WG software, the average daily ...
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. In this study , At first, meteorological data was reviewed between 1993 and 2018. Then, using LARS-WG software, climate change modeling was compared with the output data from climate change modeling in the period 2046-2065. Considering the changes in modeling in the LARS-WG software, the average daily maximum and minimum temperature can be incremental over the period 2046-2065 and also, the average daily precipitation can be decreased. Although, the average amount of daily rainfall has decreased but number of extreme points of daily precipitation during the modeling can be increased. After extraction of maximum daily rainfall data in two periods from 1993 to 2018 and 2046 to 2065 by choosing Log Pearson's 3rd Distribution, rainfall is estimated at diffrent return periods. Finally, by comparing the amount of rainfall corresponding to the floods in these two periods, Finally, comparing the amount of rainfall corresponding to the floods in these two periods was concluded that on average, these extreme rainfalls during the period from 2046 to 2065 could increase by about 15%.
Original Research Paper
Economic Geology
Rasoul Sepehrirad; Saeid Alirezaei
Abstract
The Gazestan iron-apatite deposit in the Bafq mining district, is hosted in the upper Proterozoic-lower Cambrian volcanic-sedimentary sequence, known as Rizu series, and shallow intrusions. In backscattered electron (BSE) images, the apatite displays irregular light and dark zones with variable compositions. ...
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The Gazestan iron-apatite deposit in the Bafq mining district, is hosted in the upper Proterozoic-lower Cambrian volcanic-sedimentary sequence, known as Rizu series, and shallow intrusions. In backscattered electron (BSE) images, the apatite displays irregular light and dark zones with variable compositions. The dark zones contain inclusions of monazite and xenotime, and are distinguished by depletions in LREE+Y, Na and Cl, and enrichments in Ca and P. Development of reaction rims around apatite crystals, the occurrence of monazite and xenotime as scattered fine grains as well as filling microfractures in the dark zones, and the occurrence of the REE minerals at apatite-magnetite boundary provide evidence for alteration of the original apatite crystals in Gazestan. There is evidence that the apatite crystals formed during original magnetite-apatite ore formation, interacted and reequilibrated with fluids. During a coupled dissolution-reprecipitation process, the original apatite partially reacted with fluids of external origin. This led to leaching/reprecipitation of certain components, in particular the REEs, and development of dark apatite zones with fine, scattered monazite and xenotime grains, as well as the occurrence of fine REE mineral grains across microscopic fractures in apatite, calcite and quartz.
Original Research Paper
Hydrology
Mostafa Naderi
Abstract
The Dorudzan dam inflow is assessed using SWAT under climate change. The daily simulated precipitation and temperature data by 22 general circulation models under RCP2.6, RCP4.5 and RCP8.5 are downscaled at five climatic stations using LARS-WG statistical model and transient change factors approach. ...
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The Dorudzan dam inflow is assessed using SWAT under climate change. The daily simulated precipitation and temperature data by 22 general circulation models under RCP2.6, RCP4.5 and RCP8.5 are downscaled at five climatic stations using LARS-WG statistical model and transient change factors approach. The precipitation over the watershed will decrease from 668 mm during the observation period to 572, 509 and 529 mm under the RCP2.6, RCP4.5 and RCP8.5, respectively (14.4%, 23.8% and 20.8%). The mean annual evapotranspiration will increase by 30%-36% due to increased mean annual temperature by 1.7-3.3 ℃ under three RCPs. The mean annual inflow will decrease from 28.6 m3/s to 16.7, 11.44 and 12 m3/s under the RCP2.6, RCP4.5 and RCP8.5, respectively (42%, 60% and 58%). The mean monthly reservoir volume will decrease from 490 MCM to 350, 232 and 247 MCM under the RCP2.6, RCP4.5 and RCP8.5, respectively while the dam outflow will decrease from 60 MCM/month to 43.3, 29 and 30.9 MCM/month, respectively due to the precipitation reduction by 160 mm (24%) and evapotranspiration increase by 100 mm (36%) over the watershed. The reduction of reservoir volume will intensify the downstream water shortage and crisis in the future.
Original Research Paper
Tectonics
zahra kamali; hamid nazari; ahad fazeli; faramarz alah vardi migoni; mohamad ali shokri; firooz jafari; hossin iranshahi
Abstract
The Dorud fault, as one of the most important seismic in segments of Zagros main recent fault, near the Arjng area it have northwest-southeast trend and continuity extended in Boroujerd area. Geophysical impressions in 5 profiles, and three resistivity, magnetometric and radionuclide parallel profile ...
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The Dorud fault, as one of the most important seismic in segments of Zagros main recent fault, near the Arjng area it have northwest-southeast trend and continuity extended in Boroujerd area. Geophysical impressions in 5 profiles, and three resistivity, magnetometric and radionuclide parallel profile and parts of one profile were performed. After the completion of field operations and data acquisition, GPR and magnetometer data were final processed in Radexproler and Geosoft software’s, respectively and with combining them in PA software, clearer interpretation of the subsurface structures, especially faults and discontinuities area were obtained. Among these, the F1 fault was considered as the main fault and F2 was the branching branch of the faulty branching out of it. For this reason, the Drood fault in this range is a fault zone with branching fissures branching out to the northeast This fault zone is located at the level of Silakhor plain with a length of several tens of kilometers, a variable height between 50 cm and 7 meters and with approximate dip 60-75 degree toward the north. all of these fault branches have a mechanism and according to their normal slip component.
Original Research Paper
Petrology
Fahollah Mossavvari; Reza Zarei Sahamieh; Adel Saki; Amirali Tabakh Shabani; Ahmad Ahmadi-khalaji
Abstract
The metamamorphic rocks of Sanandaj-Sirjan Zone (SSZ) in the west part of Hamedan at CheshmehGhassaban village were intruded by olivine gabbro- gabbro at the middle Jurassic. The rocks consist of olivine, clinopyroxene, plagioclase, phologopite, brown amphibole and biotite and belong to alkaline series, ...
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The metamamorphic rocks of Sanandaj-Sirjan Zone (SSZ) in the west part of Hamedan at CheshmehGhassaban village were intruded by olivine gabbro- gabbro at the middle Jurassic. The rocks consist of olivine, clinopyroxene, plagioclase, phologopite, brown amphibole and biotite and belong to alkaline series, derived from partial melting in the stability field of a garnet peridotite. Moreover,LREE enrichment in chondrite normalized REE pattern, and relatively high ratios ofLaN/YbN (6.65-11.25)، Nb/Yb(22-22.38),Th/Nb(0.07-0.16) and Nb/Y (>1)indicate that the rocks originatedfrom an ocean island basalt like (OIB-like) sublithospheric mantle source and juxtaposed with and intruded into continental crust. With respect to geodynamic model of SSZ in the Alvand area in the middle Jurassic, ascribed to the subduction of the Neo-Tethys oceanic crust below the SSZ, the "Ridge-Trench" subduction model is proposed for thes egabbros. Based on this model, the subduction of the active spreading center of the Neo-Tethys oceanic crust produceda slab window in the subducted oceanic lithosphere, allowing infiltration of astenospheric hot OIB-like melt into SSZ. In addition, the development of a very substantial volume of S-type granitoid rocks in the Alvand granitoid complex of Hamedan region can be attributed to the melting of the metapilitic rocks due to ridge subduction events
Original Research Paper
Economic Geology
Mohammad Jabarian; mehrdad karimi; Mohammad Lotfi; kamal noori khankahdani
Abstract
Dehkooye salt dome is located 30 km northeast of Lar in Fars province, Iran. The salt dome occurred in Zagros folded zone where infracambrian thick evaporate strata (Hormoz series) intruded Cenozoic sedimentary rocks. Core of the dome mainly made up of salt and gypsum and overlain by marl, gypsum, limestone, ...
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Dehkooye salt dome is located 30 km northeast of Lar in Fars province, Iran. The salt dome occurred in Zagros folded zone where infracambrian thick evaporate strata (Hormoz series) intruded Cenozoic sedimentary rocks. Core of the dome mainly made up of salt and gypsum and overlain by marl, gypsum, limestone, and dolomitic formations. Besides primary stratiform mineralization, epigenetic iron and copper mineralization occurred mostly within dolomitic lime stone members in the cap rock of the salt dome in Hormoz Formation. Ore mineralogy is simple and includes hematite, minor goethite, and sparse occurrence of magnetite. Chalcopyrite is evident as minor phase. Samples for fluid inclusion studies were collected from sulfide-bearing quartz veins and veinlets. According to homogenization temperature (Th: 172-374 ° C with average 374° C), which in fact represents the boiling point of the irrigation solution, indicate the epithermal to the beginning of hypothermal conditions and the mean of the beginning of the mesothermal. The depth formation of deposit was between 50 to 1500 meters and an average of about 200 meters. The hydrothermal solutions forming the ore deposit, due to their high salinity, have the origin of magmatic brine that have been displaced because of low density and tectonic pressures. This solutions have climbed upwards along faults and fractures and after being mixed with meteoric waters, epigenetic mineralization is created.
Original Research Paper
Stratigraphy and Palaeontology
Tayebe Sarbandi Farahani; Mehdi Yazdi; Mahmoud Reza Majidifard
Abstract
This paper focused on the systematic of the benthic foraminifera from the Chaman Bid and Goznawwi sections. At the type locality of the Chaman Bid Formation, consists of alternation of limestone (grainstone to wackstone), argilasious limestone and marl. The age of tha Chaman Bid Formation based on ammonite ...
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This paper focused on the systematic of the benthic foraminifera from the Chaman Bid and Goznawwi sections. At the type locality of the Chaman Bid Formation, consists of alternation of limestone (grainstone to wackstone), argilasious limestone and marl. The age of tha Chaman Bid Formation based on ammonite fauna range from ?Bathonian to late Tithonian. and the age. Near the Azadshar, the Farsian Formation is exposed and consists of fossilferous the soft marl, sandstone, limestone and silt which based on ammonite, age of this sediment considered as Callovian. Two studied sections are bearing well - preserved foraminifera which most belong to Lagenina (most belong to Nodosaridae and Vaginolinidae families) and Rotalina (Epistominidae); total 23 genus and 39 species from Goznawwi and 10 genus and 16 species from Chaman Bid sections. The 28 species of the benthic isolated foraminiferal assemblages are first recorded from Iran. In additional, based on this study, Iranian assemblage of foraminifers at this time are most similar to those of the North of the tetyan releam.
Original Research Paper
Petrology
gholamreza ghadami; Mohammad Poosti
Abstract
The studied area is located in the north of Rudan city, Groom mountain, in the contact area of the Zagros and Makran zones and some part of Kahnuj-Rudan-Minab ophiolite belt. The studied ultramafic rocks include lherzolite and harzburgite, matrix minerals contains olivine, orthopyroxene, clinopyroxene ...
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The studied area is located in the north of Rudan city, Groom mountain, in the contact area of the Zagros and Makran zones and some part of Kahnuj-Rudan-Minab ophiolite belt. The studied ultramafic rocks include lherzolite and harzburgite, matrix minerals contains olivine, orthopyroxene, clinopyroxene and chromian spinel which is a minor mineral. Based on the geochemical data, the amount of CaO, MgO, TiO2 and V, these rocks belong to non serpentinized orogenic ophiolites. According to microprobe data, the high amounts of Mg#(91.15-93.24) in the lherzolite olivines are indicated that these olivines had refractory and restite, also lherzolite clinopyroxenes are also of the diopside quality, but spinels have poor chromian. Detailed microprobe studies on the spinel of these rocks, ndicated of the high amounts of Mg#(71-77) and Al2O3(52.98 to 46.31Wt%) ) and low Cr#(14-22). Cr/Al proporation of in chromian spinels of lherzolites are equal to 0.19 and amount of Fe3+ in the lherzolite spinels is very low (
