Editor-in-Chief Lecture
Volume 22, Issue 88 , December 2013, Pages 1-1
Reviewers
Volume 22, Issue 88 , December 2013, Pages 2-2
Original Research Paper
N Etemad-Saeed; M. H Adabi; A. Sadeghi; M. Hosseini- Barzi
Abstract
This work is focused on tectonic provenance of the Late Neoproterozoic Kahar Formation in the northern Iran. KaharMountain (type locality) provides valuable information on tectonic events during this time. The Kahar Formation in this area is a well preserved sedimentary sequence and consists of about ...
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This work is focused on tectonic provenance of the Late Neoproterozoic Kahar Formation in the northern Iran. KaharMountain (type locality) provides valuable information on tectonic events during this time. The Kahar Formation in this area is a well preserved sedimentary sequence and consists of about 1000 meters of predominantly fine grained siliciclastic rocks and minor sandstones, conglomerates and dolomitized stromatolites. Kahar lithic arkose sandstones with low compositional and textural maturity, contain abundant feldspar (plagioclase and K feldspar), quartz, and volcanic lithic fragments and have an average composition of Q38F40L22, Qt39F40L21, Qm32F40Lt28,Qp27Lvm60Lsm13 and Qm44P33K23 suggesting a proximal source and a dissected arc setting. The type of lithic fragments in the sandstones show andesitic and felsic volcanic rock sources. Heavy mineral analysis (abundant metastable and unstable minerals such as biotite, and pyroxenes) indicate that Kahar sandstones were derived from unroofing of arc-type magmatic rocks. The low diversity of heavy mineral assemblages in the Kahar sandstones indicates that the source rocks were uniform and localized. Considering the two common tectonic views regarding the Late Neoproterozoic condition of Iran (rift-passive margin and magmatic arc-subduction zone), the results of this study which confirm the magmatic arc tectonic setting of Alborz-Iran at that time seems critical.
Original Research Paper
H Safari; M. R. Ghassemi; M. Agh- Atabay; R. Razavi pash
Abstract
Lahijan fault zone is one of the transverse faults in western Alborz which with, sinistral mechanism caused structural deformations in this region. In this research, with using of field investigations, Remote Sensing techniques and statistical structural analysis methods, the structural analysis of Lahijan ...
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Lahijan fault zone is one of the transverse faults in western Alborz which with, sinistral mechanism caused structural deformations in this region. In this research, with using of field investigations, Remote Sensing techniques and statistical structural analysis methods, the structural analysis of Lahijan fault zone is performed and consequently, the fault zone (Geometry) is constructed. On the basis of results of this research, the Lahijan fault with attitude N 55/70-SE has 30 Km width. This fault zone is considered as sinistral fault zones which have different related fractures. The fractures related fault zone are ordered as syntethic and Antithetic faults. Most of faults in this fault zone have Net- slip movements and the angle of these to main fault zone, specified their mechanisms so, the parallel faults zone have left- lateral movements and in opposite, the faults with angle of 75˚ related to fault zone trend, have Right- lateral movements. Due to progressive sinistral deformation, all of structures rotated counter- clockwise and placed in lesser angle relative to this shear zone.
Original Research Paper
M. Paknia; Habib Alimohammadian; M. R. Majidifard; J. Sabouri; A. Aghanabat
Abstract
The Golbini section comprising of continuous succession of sediments ranging in age from Triassic – Jurassic formations, is situated at 35 Km north – east of Jajarm city. On the bases of studies on Dalichai Formation at this section and at about Middle Jurassic (Bathonian–Callovian ...
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The Golbini section comprising of continuous succession of sediments ranging in age from Triassic – Jurassic formations, is situated at 35 Km north – east of Jajarm city. On the bases of studies on Dalichai Formation at this section and at about Middle Jurassic (Bathonian–Callovian boundary), 3 Member, 31 Genus and 13 species of Ammonite, has been identified. For paleomagnetic analysis, with the help of portable coring machine, the total number of 155 oriented core samples were collected from limestone and clayey– limestone of this section. Then the samples were prepared for paleomagnetic analysis at Environmental and Paleomagnetic Laboratory based at Geological Survey of Iran, Tehran, Iran. The conducted paleomagnetic analysis include measurement of NRM, Susceptibility, Thermal and AF demagnetizing, Virtual Geomagnetic Polarity (VGP), identification of normal and reversal magnetic polarities and calculation of sedimentation rate. The obtained paleomagnetic results then composed with GPTS and also with proposed Bathonian–Callovian boundaries in Russia and Germany. This comparison reveals that the magnetic polarity of Golbini section is co-relatable with GPTS and also with Bathonian–Callovian boundary in Russia and Germany.
Original Research Paper
Z. Jeddi; Mohammad Tatar; B. Saeedi Razavi
Abstract
The catastrophic December 26, 2003 Mw 6.6 Bam earthquake is one of the most disastrous earthquakes in Iran. This earthquake attracted much attention, and has been far more studied that which would be expected from a moderate magnitude earthquake. Nevertheless, there are doubtful results related to geometry ...
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The catastrophic December 26, 2003 Mw 6.6 Bam earthquake is one of the most disastrous earthquakes in Iran. This earthquake attracted much attention, and has been far more studied that which would be expected from a moderate magnitude earthquake. Nevertheless, there are doubtful results related to geometry and location of the causative fault that produced the Bam earthquake. As very little is known about the 3-D structure of the region and in order to define the 3-D velocity structure and the geometry of the active fault in the Bam area travel time data from the aftershock series of the Bam earthquake are inverted simultaneously for both hypocenter locations and 3-D Vp structure. The data used for this purpose are 6201 P-wave arrival times from 544 selected local earthquakes recorded by temporary 23 short-period seismic stations. 3-D P-wave velocity variations down to 20 km depth were obtained. The acquired tomographic images show that the 3-D velocity structure beneath the region is heterogeneous in that low velocity appears throughout the region down to ~10 km depth, and high velocities occur in western part from ~14 km depth. Velocity structure of seismogenic region is well resolved to a depth of 20 km. Difference in observed velocities in two sides of the Bam fault in depth of 10-20 km is clear in tomographic images and on cross sections. We relate this difference in velocity to the effect of the reverse Bam-Baravat fault which seems influenced the deeper layer down to 20 km depth. This implies that the pre-existing reverse Bam-Baravat fault is a major active structure in the region that could be caused the December 2003 Bam earthquake.
Original Research Paper
S. Sadeghi; A. Yassaghi; M. Fathollahi
Abstract
In this paper, the structural relationship between two main structural features of the Zagros suture zone, that is, the Main Zagros Reverse Fault (MZRF) and the Main Recent Fault (MRF) in Kurdistan area has been studied in more detail. This provides information as to the structural evolution and seismotectonics ...
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In this paper, the structural relationship between two main structural features of the Zagros suture zone, that is, the Main Zagros Reverse Fault (MZRF) and the Main Recent Fault (MRF) in Kurdistan area has been studied in more detail. This provides information as to the structural evolution and seismotectonics of the Zagros suture zone. Around latitude 36, the Sardasht segment of the MRF cut the MZRF and toward southeast part of this intersection, the MRF is the only major fault between the Zagros fold- thrust belt and the Sanandaj- Sirjan zone. Here, segments of the MZRF can be seen in the MRF zone, which represents the younger activity of the MRF. Our investigation show that there is a right- hand bending between the Piranshahr Fault in the northwest and the Marivan Fault in the southeast (between latitudes 35 ̊, 30' and 36 ̊, 30'). On the southwest and northeast edges of this releasing bend, the Sardasht and Baneh faults are located that have both strike-slip and normal components. Considering geometric and kinematic aspects of the curved segment of the MRF (Sardasht Fault), as well as the paleostress studies of this segment, it can be said that the Sardasht Fault with N30W trending fault has deviated from the main displacement vector (N60W) and hence has a normal component. Therefore, this fault accommodates dextral and transpressional movements between the Zagros fold- thrust belt and the Sanandaj-Sirjan zone and its normal movements arising from the right hand bending of the MRF. Paleostress analysis (using the Multiple Inverse Method) shows separate stress fields for different movements. Paleostress fields have a close correlation with the stress fields obtained from the focal mechanism of the earthquakes located along the Zagros suture zone. This correlation shows that the obtained stress fields are belong to younger activity. Displacement of the MZRF by the MRF caused significant heave in the MZRF and thus it does not expose at the surface between latitudes 35 ̊, 20' and 36 ̊, 00'.
Original Research Paper
B Alizadeh; R. Fouladvand
Abstract
The main goal of this study is to introduce a paleo high in the central part of Binak oilfield using geochemical parameters. Despite the effect of this phenomena on sedimentation, due to its low amplitude of uplift and lack of unconformity, so far remained unknown in this oilfield. Seismic and well log ...
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The main goal of this study is to introduce a paleo high in the central part of Binak oilfield using geochemical parameters. Despite the effect of this phenomena on sedimentation, due to its low amplitude of uplift and lack of unconformity, so far remained unknown in this oilfield. Seismic and well log data reveal that, Binak oilfield is an asymmetrical anticline with Bangestan reservoir of about 22 km long and 10 km wide. To investigate the paleo high in the oil field, geochemical analyses were performed on the cutting samples by Rock Eval 6 Pyrolysis, Vitrinite reflectance measurement and finally Pars Basin Modeler software was used for thermal modeling. The results of Rock-Eval analysis demonstrate that the quantity of total organic carbon decreases in all the Kazhdumi, Lafan, Gurpi and Pabdeh Formations towards the center of this anticline. This phenomenon reveals that the environment and condition of sedimentation have been oxidation and shallow for these formations during their deposit history in the center. This can be explained by development of an uplift along Kharg - Mish basement fault starting at or before Albian to Cenomanian time. The Kazhdumi Formation in well number four indicates a drastic change in the geochemical data in compare to other formations as well as the same formation in well number seven. This can also be correlated to remarkable increase in the activities of Kharg-Mish Fault during Albian. On the other hand significant temperature anomalies are often observed close to the faults and there is a direct relationship between basement fault, high thermal gradient and paleo highs. Therefore, thermal modeling was performed to understand thermal history of this oilfield using PBM (Pars Basin Modeler) software. The results indicate that, the amount of heat flow must be 80, 76, 66 and 60 mW/m2 for well numbers 2, 4, 6 and 7 respectively for achievement of the best fit between calculated Vitrinite reflectances as well as Tmax parameters and the same parameters actually measured by geochemical analyses. Consequently, this study reveals that there is a paleo high in the centre and along the Kharg – Mish Fault of the oil field which caused low content of TOC and naturally lower potential for hydrocarbon generation in the middle part of the oilfield. Finally considering the reservoir in the Binak oilfield, since in the central part is shallower due to the paleo high, there is more Rudist presence and higher oil production in the central part of the oilfield.
Original Research Paper
M Yamani; A. A. Shamsipour; M. Jafari Aghdam; S. Bagheri Seyed shokr
Abstract
The Cheleh basin is located in the south of Kermanshah province and the Zagros morphotectonic zone. According to the vast of limestone formation, and the presence of tectonic faults, developed karst land forms has evolved. The purpose of this study is to survey the development of karst and the effect ...
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The Cheleh basin is located in the south of Kermanshah province and the Zagros morphotectonic zone. According to the vast of limestone formation, and the presence of tectonic faults, developed karst land forms has evolved. The purpose of this study is to survey the development of karst and the effect of permeable factors on it. Main data of the research are formed by topographic and geologic maps and aerial photos along with hydrology stats of Department Energy. In this study are nine environmental factors as independent variables and Geomorphological karstic landforms as the dependent variable were examined. At first was identified quantitative and qualitative criteria and then doing field works, interviews and questionnaires, these criteria and factors are analyzed using Analytical Hierarchy Process and finally were gained in GIS, maps and unificating and Final correction with the help of fuzzy logic, respectively. In order to better conclusions, the region in terms of development in karst was divided into four sections. Combining data layers approve the effective role of lithology (Asmari Formation) in the process of development in karsting. Also has seen development in karst on the southern highlands of basin and flat lands at the head of the northern anticline and along the main fault of the region. karst areas Developed 107.95 square kilometers about 22.5 percent and regions with average development of karst covers 34 percent of the watershed basin.
Original Research Paper
M Yari; R. Mohebian; M. A. Riahi
Abstract
Instantaneous spectral attributes such as center frequency, root-mean-square frequency and bandwidth often are extracted from time-frequency spectrum to describe frequency- dependent rock properties in exploration seismic. These attributes are defined using probability theory. A time-frequency map (spectrogram) ...
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Instantaneous spectral attributes such as center frequency, root-mean-square frequency and bandwidth often are extracted from time-frequency spectrum to describe frequency- dependent rock properties in exploration seismic. These attributes are defined using probability theory. A time-frequency map (spectrogram) can be obtained from methods such as short-time Fourier transform (STFT), continuous-wavelet transform (CWT) and time-frequency continuous-wavelet transform (TFCWT) that methods CWT and TFCWT does not require preselecting a time window, which is essential in STFT and have better time-frequency resolution than STFT. In this paper is applied method using mathematical formulas which compute the instantaneous spectral attributes from the scalogram that these attributes are similar to attributes obtained from spectrogram TFCWT. Except that here not need to convert scalogram into spectrogram computing time will be longer.
Original Research Paper
M. Lotfi; S.F Sadjadi AleHashem; M. H. Emami
Abstract
Boznein manganese deposit is located in 25 km south-southwest of Ardestan, part of Urmiyeh-Dokhtar magmatic belt. The main units in the studied area are volcanic-pyroclastic sequences & intrusive bodies of middle Eocene-lower Oligocene. Porphyroid rhyolitic dome (upper Eocene-lower Oligocene) is ...
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Boznein manganese deposit is located in 25 km south-southwest of Ardestan, part of Urmiyeh-Dokhtar magmatic belt. The main units in the studied area are volcanic-pyroclastic sequences & intrusive bodies of middle Eocene-lower Oligocene. Porphyroid rhyolitic dome (upper Eocene-lower Oligocene) is host rock of economic Mn mineralization. The mineralization occurred as veins trending mostly NE-SW of interrupted total length of 1.5 m width at two active mines of 1 and 2. Exploitable reserve of the mine is estimated to be 60,000 tons of an average grade of 50.18% MnO. The main Mn ore minerals including braunite, bixbyite, hausmanite, spessartine rhodochrosite, manganite, pyrolusite, psillomelane, cryptomelane that by As and Cu minerals. Ores shows massive, microcrystalline, euhedral, colloform, colloidal, bubble form, acicular, tabular, veinlet, breccia, stockwork and residual textures. In base of ore samples geochemical characteristics and comparison with studied Mn types and deposits, indicate a good match with hydrothermal Mn-deposits. In base of mineralization form, host rock petrography and age, ore texture and structure, mineralogy, geochemical characteristics and genetic controlling factors, the Boznein deposit shows similarities with epithermal Mn-deposit. Non-economic syngenetic Mn-mineralization in the unit older than rhyolitic dome can be considered as the possible source of the Mn. Contemporaneous with intrusion rhyolitic dome, Mn concentration led to high grade epigenetic Mn vein in surrounding porphyroid rhyolitic dome.
Original Research Paper
M Royatvand; A Bahroudi; M. Qoreshi; M. R. Ghasemi; S. A. Aghahosseini
Abstract
The Oligocene salt in the Garmsar and Eyvankey plateau, south–central Alborz, has extruded on the quaternary sediments and formed a salt glacier. This open-toe salt glacier is about 24×17 km that is unique continental salt glacier in the world, dimensionally. Also, this ductile substrate ...
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The Oligocene salt in the Garmsar and Eyvankey plateau, south–central Alborz, has extruded on the quaternary sediments and formed a salt glacier. This open-toe salt glacier is about 24×17 km that is unique continental salt glacier in the world, dimensionally. Also, this ductile substrate has affected on structural styles of this region. However, little systematic work has done on it. To investigate the structural styles of the region that affected by a ductile substrate and adjacent region with a frictional decollement, and also the structures of the salt glacier,series of models were done which were scaled sandbox models. These sandbox models simulated the propagation of deformation of thin-skinned simultaneous shortening above adjacent ductile and frictional of two end member of decollement. Model results illustrate that above a ductile substrate, deformation propagates further and more rapidly than above a frictional substrate as we can see in the nature that the region with a ductile substrate is so broader than the adjacent region with a frictional decollement. Like the models, toward the north in the nature where the Decollement is frictional, from North Tehran Fault as a frontal fault to Mosha and Kandovan Faults in the core of Alborz Mountain, the dip of the faults are increased and only forward-vergent imbricate faults, whereas above the ductile substrate the dip of faults has not a definite pattern of dip and also, both foreland and hinterland imbricate faults develop.
Original Research Paper
E. Haghighi; S. Alirezaei; E. Ashrafpour
Abstract
The Cheshmeh Hafez deposit in Torud-Chahshirin Range, north-central Iran, consists of a polymetal vein mineralization in Cenozoic volcanic host rocks of dominantly basaltic andesite and dacite compositions. The main ore vein, 1800 m long and <1 – 5 m wide, occurs discontinuously in a north-south ...
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The Cheshmeh Hafez deposit in Torud-Chahshirin Range, north-central Iran, consists of a polymetal vein mineralization in Cenozoic volcanic host rocks of dominantly basaltic andesite and dacite compositions. The main ore vein, 1800 m long and <1 – 5 m wide, occurs discontinuously in a north-south direction, and includes chalcedony, fine- to coarse-grained quartz, and jasperoid, associated with galena and subordinate chalcopyrite, sphalerite, bornite, pyrite, tetrahedrite, specular hematite and siderite. Crustiform bands, consisting of grey chalcedony, jasperoid, milky quartz, and various ore minerals are common, and breccias and comb textures are locally developed, in the vein. Supergene processes led to the replacement of galena by cerussite, and of hypogene copper minerals (chalcopyrite and bornite) by covellite and malachite. The main ore vein is accompanied by several smaller quartz and calcite veins in NE-SW and E-W directions, respectively, where the calcite veins are barren. Alteration related to mineralization is restricted to thin halos bordering the vein, and consists of quartz, chlorite, calcite, kaolinite and sericite (illite). Fluid inclusions in quartz associated with ore minerals are studied. Most inclusions are two-phase, liquid-rich, at room temperatures; few are vapor-dominant, and few consist solely of liquid. Primary fluid inclusions display low to moderate homogenization temperatures (135-285) and salinities (1-13 wt% NaCl equivalents). The δ34S values for the ore fluids in equilibrium with the sulfide minerals fall in the range -1.6 to +4.1‰ and suggest a magmatic source for sulfur. The ore and gangue mineralogy, and the alteration assemblages, suggest that the ore fluids were reduced and near-neutral in nature. This, combined with the metal contents, Ag/Au ratio between 16 to 25, iron- poor sphalerite, the crustiform and colloform textures, and the Th and salinity values, imply that mineralization at Cheshmeh Hafez is of epithermal, intermediate- sulfidation, character. The alteration assemblage at Cheshmeh Hafez is indicative of a sub-type of intermediate- sulfidation epithermal deposits with a tendency towards low-sulfidation type
Original Research Paper
A. Pouresmaeil; F. Hadavi; R. Lak
Abstract
In this study, a core with 10.5 m lenght and in shallow water in Bandar Abbas (Shahid Rajaee Port area) was studied based on calcareous nannoplankton. In this study, 52 samples of sediment cores were taken and prepared. Most species were photographed by light microscope. For the first time 21 genera ...
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In this study, a core with 10.5 m lenght and in shallow water in Bandar Abbas (Shahid Rajaee Port area) was studied based on calcareous nannoplankton. In this study, 52 samples of sediment cores were taken and prepared. Most species were photographed by light microscope. For the first time 21 genera and 35 species introduced in this area. In the core mentioned Gephyrocapsa oceanica and Emiliania huxleyi are the dominant taxa, based on the abundant presence of these species can be concluded that the Persian Gulf basin is a marginal sea in the lower latitudes and shallow areas have been formed and in this area productivity of nannoplankton is high.
Original Research Paper
A. Karimian Torghabeh; S.R Moussavi-Harami; A. Mahboubi
Abstract
Siliciclastic succession of Pesteliegh Formation, Lower Paleocene, has an extensive exposure in the Kopet Dagh basin. Three stratigraphic sections, consist of Dareh Gaz, Shamsikhan and Karnaveh in central Kopet Dagh, were measured and studied for environmental interpretation and sequence stratigraphic ...
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Siliciclastic succession of Pesteliegh Formation, Lower Paleocene, has an extensive exposure in the Kopet Dagh basin. Three stratigraphic sections, consist of Dareh Gaz, Shamsikhan and Karnaveh in central Kopet Dagh, were measured and studied for environmental interpretation and sequence stratigraphic analysis. This study led to identification of 8 lithofacies (Gcm, Gmg, Gt, Sm, Sh, Sp, St و Fm) and 5 architectural elements ( OF, CH, SB,GB,SG). Based on this data, siliciclastic sediments of Pesteliegh Formation were deposited in both fine-grain meandering and braided river systems. Sequence stratigraphy analysis show that siliciclastic sediments of the Pesteliegh Formation deposits is composed of two depositional sequences that were effected by tectonic and base level changes during the sea level fall. Both depositional sequences consist of LE and TE phases. Paleogeographic reconsruction of the Early Paleocene time show that these deposits were formed during 4 different stages in relation to changes in accommodation space.
Original Research Paper
R. Monazzami bagherzadeh; H. Mirnejad; P. Eshback; M. H. Karimpour
Abstract
Listvenites or ophiocarbonates are considered important for exploration of precious and base metlas particularly Au, Ag, Cu, As and Hg. These rocks, which crop-out dominantly in ophiolite-mélange zones and in the vicinity of main faults and shear zones, have formed as the result of hydrous ...
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Listvenites or ophiocarbonates are considered important for exploration of precious and base metlas particularly Au, Ag, Cu, As and Hg. These rocks, which crop-out dominantly in ophiolite-mélange zones and in the vicinity of main faults and shear zones, have formed as the result of hydrous and carbonic alteration of ultramafic rocks. Listvenites occur extensively in eastern Iran. Based on petrography, Hangaran listvenites are grouped into three major types: 1. Carbonatic listvenite (type I), 2. Silicic listvenite (type II), and 3. Sulfie-bearing silicic listvenite with brecciated texture (type III). Gold contents of listvenites is generally low and the highest concentration (290 ppb) has been found in type III. Studies of mineral concentrates from stream sediments reveal the presence of gold, pyrite, chalcopyrite, cinnabar and native copper. Gold grains reach to a maximum sizes of 80 microns, and they are often associated with pyrite. Electron microprobe analyses on several sulfides and carbonates in Hangaran listvenites show that sulfide minerals are mainly pyrite, marcasite, bravoite and to a lesser amount chalcopyrite, and that many pyrite grains have been altered to marcasite. Important carbonated minerals are magnesite and dolomite. The presence of obiquitous bravoite zonation that results from alternations in Ni content indicates periodic changes in the physicochemical conditions of the hyrdorthemal solution. Petrographic studies and paragenetic sequence of minerals show that magnesite and dolomite formed prior to the mineralization stage, which was then followed by the formation of sulfides (mainly pyrite). Studies on the oxygen and carbone isotopes in 3 dolomite samples (δ18OSMOW = 9.353- 9.982 ‰, δ13CPDB =1.57- 1.67 ‰ ) show that oxygen and carbone can originate from oceanic waters, and that dolomite has formed due to the circulation of this water in ultramafic rocks and their subsequent alteration. Considering the variation in marcasite-pyrite paris from Hangaran silicic listvenite (δ34SCDT value 5.7-7.9 ‰ ), it seems that sulfur has originated from granitic rocks in south of the study area. Taking into accout the extentive outcrops of serpentinized ultramafic rocks and granite in the region can considered the source of Au, Ag and base elements such as Cu, Pb, Zn, Hg, As, Sb in related to granite masses, and Cr, Ni, Ti and Fe in related to serpentinized ultramafic rocks. Fluid inclusion studies on mineralized quartz in Hangaran listvenites show that the hydrothermal fluid affecting the host rocks was low salinity and had a maximum temperature of 280ºC.
Original Research Paper
SH. Gholipouri; P. Ghazanfari; M. Almasian; N. Jalali
Abstract
Vardeh drainage basin is located at north of Karaj and belongs to Central Alborz structural zone and its climate is semi-humid. The area of Vardeh basin is 68,97km2. Formations in this basin mainly include shale, tuffaceous shale, tuffaceous sandstone and limestone. The age of Kahar Formation is Precambrian, ...
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Vardeh drainage basin is located at north of Karaj and belongs to Central Alborz structural zone and its climate is semi-humid. The area of Vardeh basin is 68,97km2. Formations in this basin mainly include shale, tuffaceous shale, tuffaceous sandstone and limestone. The age of Kahar Formation is Precambrian, the oldest formation and quaternary alluvial deposits are the youngest deposits at this basin. The aim of this study is Investigation of susceptibility of formations to erosion with qualitative methods, assessment of physiographic and geomorphology and quantitative ways, MPSIAC model and sedimentary yield. In this research, library studies, field surveys, interpreting Arial photos were carried out. The collected data taken into account from geometry factors, in V1 sub – basin minimum slope and altitude and in v7-2 maximum slope and altitude. Vardeh basin is divided into mountain (M,m), hills(h), and alluvial deposit (Qal,Qt). Mio fancies forms the most area of the basin. In MPSIAC model the effect of nine and EPM model the effect of 4 important factors on soil erosion and sediment yield were evaluated. Numerical values were assigned to them in terms of intensity and weakness of each factor. Using the sum of those values different factors, the amount of sediment yield in basin was calculated as Qs= 0.253e0.036R and finally the map for each of the 9 factors were prepared in Arc GIS environment. According to identifying sub- basins with high sediment yield, V2 and V3 sub- basins deposit and this basin shall be among first priority for soil protection planning.
Original Research Paper
M. H. Ahmadi; G.H Shamanian; H. Azmi
Abstract
The Motrabad vein system is located 30 Km southwest of Bajestan in the northern part of the Lut Block. The vein host rocks consist of intermediate to silicic volcanic rocks. The mineralization occurs as irregular veins, veinlets and hydrothermal breccias. Based on field geology and textural evidences ...
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The Motrabad vein system is located 30 Km southwest of Bajestan in the northern part of the Lut Block. The vein host rocks consist of intermediate to silicic volcanic rocks. The mineralization occurs as irregular veins, veinlets and hydrothermal breccias. Based on field geology and textural evidences four types of quartz veins (A, B, C and D) were identified. Hydrothermal alteration is developed around the veins and tends to be more intense in the vicinity of the veins. Hydrothermal alteration consists of silicic, sericitic, propylitic and argilic assemblages. The plot of the Ishikawa alteration index (AI) Vs. chlorite-carbonate-pyrite index (CCPI), known as alteration box plot, display the main alteration trends. The hydrothermal alteration assemblage of quartz, adularia, chlorite, illite, calcite, and pyrite that envelopes the Motrabad vein system formed from the upwelling of near-neutral to weakly alkaline chloride waters. The mineralogic, alteration and geochemical characteristics of the studied area and their comparison with epithermal ore deposits represent an epithermal system of the low-sulfidation type.
Original Research Paper
G. Daneshian; S. A. Moallemi; A. A. Azad
Abstract
In this research, the Sarvak Formation and lower part of the Surgah Formation in Kabirkuh anticline, southeast Ilam with thickness of 897 m were studied. Prospect of changes in umbilical structures of planktonic foraminifera such as lip, ortico throughout of Albian to Turonian were investigated. The ...
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In this research, the Sarvak Formation and lower part of the Surgah Formation in Kabirkuh anticline, southeast Ilam with thickness of 897 m were studied. Prospect of changes in umbilical structures of planktonic foraminifera such as lip, ortico throughout of Albian to Turonian were investigated. The phylogenic trend shows that lip structure in primary morphogroups gradually replaced by ortico in more developed forms. The statistical analyses showed that the trend of the mentioned changes is comparable with increasing the water depth while a decrease in depth result in the development of lip in studied planktonic foraminifera. According to foraminifera and Oligosteginids, the age of examining succession is late Middle Albian to Late Turonian. The study of different type of morphotype groups in this section indicates that the fauna mostly belong to morphotypes number two and one, and then rarely number three. The studied morphotypes show that the main part of sedimentation carried out in relatively deep marine condition The results show that the Muricohedbergella frequency at lower and middle parts of the Sarvak Formation incompatible with the basin depth decrease that is specified with two decreasing peaks (sea regression). Also Favusella frequency in line with three increasing peaks (sea Transgression), and is a good index for showing the basin depth. In the final part of the sequence, the presence of Whiteinella to increase peaks which are compatible with the basin increasing depth and sea transgressive in studied section.
Original Research Paper
Arman Heravi; H. Nazari; A. Shahidi; M. Talebian
Abstract
The Garmsar Fault with a length of about 75 km and E-W trend is located in Garmsar.This Fault observed in north of Garmsar and eastern part of central Alborz with slop toward north, continus east of Eyvanakey Fault. Base of the morphotectonical investigation, along the Garmsar Fault this ...
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The Garmsar Fault with a length of about 75 km and E-W trend is located in Garmsar.This Fault observed in north of Garmsar and eastern part of central Alborz with slop toward north, continus east of Eyvanakey Fault. Base of the morphotectonical investigation, along the Garmsar Fault this fault is devided to 5 segments from east (Dehnamak village) to the west (Eyvanakey), with attention to this segmentation we could consider the branch of kuh-e-sorkh Fault at west of Garmsar in kuh-e-sorkh anticline such as separated fault with slop toward north and pressure mechanism with small left-lateral strike slip component. Base on observations and Paleostress measurment along the Garmsar Fault in Bon-e-kuh station and eastern segment of this fault, we could consider that Paleostress direction around Neogen Time, is N-S with pressure component. However, base of data, is gain from morphotectonical investigations, young and overcome mechanism in eastern segment (Fault segment 1) left-lateral with pressure component, on the other side, in kuh-e-sorkh anticline at western part of research area, considered stress direction at quaternary period E-W under the effect of Thrust fault with left-lateral component. Base of this study from geometry point of view, the Garmsar Fault is a fault with slop toward north which is able to devide in to 5 segments that is strike and geometry of each fault segment mechanism is from left-lateral with pressure component until Tension and the Garmsar Fault is considered as an active fault in quaternary period. Maximum and minimum on the left horizontal displacement measured on the fault equal to 220 meters and 4 meters of a fault on the part of the fault system and third segment on the drainages of Garmsar displaced is visible.
Original Research Paper
F. Khaleghi; Gh. Hosseinzadeh; I. Rasa; M. Moayyed
Abstract
The Syah kamar molybdenum deposit is a porphyry molybdenum system which has been explored during the recent research of author in the northwest of Iran and is being reported for the first time and its ore mineralization is explained and discussed in this paper on the basis of geological data, mineralization ...
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The Syah kamar molybdenum deposit is a porphyry molybdenum system which has been explored during the recent research of author in the northwest of Iran and is being reported for the first time and its ore mineralization is explained and discussed in this paper on the basis of geological data, mineralization evidences, geochemistry and fluid inclusions thermometry data. A porphyry quartz-monzonitic stock, which belongs to the K-rich (alkali-rich) calc-alkaline rock series and on the basis of geochemical data and tectonic setting viewpoint, formed as the post-collision granites is considered as the mineralization parent rock of this system. According to the emplacement pattern of productive intrusive bodies of the region, the mineralization of molybdenum have occurred after Eocene time, about the Oligocene time, and the mineralization process has taken place most probably at the last stage of magma emplacement, and on the basis of microthermometery and salinity data, its metaliferous hydrothermal solution have had low salinity and medium homogenization temperature. In addition, according to the host rock type, accompanying alterations and some other evidences, the mineralization characteristics of Syah kamar molybdenum prospect are comparable with the molybdenum deposits of the quartz-monzonitic type. During the tectonic processes, the ore-bearing hydrothermal solution ascended along weak zones and suitable fault structures, and intruded into the joints and fissures of surrounding rocks, and as a result of physiochemical changes of environment and some other effects, finally the Syah kamar molybdenum deposit has been formed.
Original Research Paper
R. Hajialioghli; M. Moazzen
Abstract
The Prototethys ocean is formed between tow giant continents of Gondwana in the north and Eurasia in the south. Iranian terrain as neigburhood countries in the Oman, Pakestan, SE Turkey has been belonged to the giant Gondwana during Precambrian and Paleozoic. Precambrian terrains in Iran show limited ...
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The Prototethys ocean is formed between tow giant continents of Gondwana in the north and Eurasia in the south. Iranian terrain as neigburhood countries in the Oman, Pakestan, SE Turkey has been belonged to the giant Gondwana during Precambrian and Paleozoic. Precambrian terrains in Iran show limited out crops including of middle part of the Central Iran in Saghand and Poshtbadam regions, Uromiyeh, Zanjan, Golpayegan, Anabolaghi (in Miyaneh) and Takab. The Takht-e-Soleyman metamorphic complex is located in the north eastern Takab. It is composed of variety of metamorphic rocks including metapelites, metabasites, calc-silicates and meta-ultramafic rocks. On the basis of fieldgeology, petrology and zircon U/Pb isotopic data, the Takht-e-Soleyman complex is comparable with the Central Iranian micro-continent. On the basis of 207Pb/206Pb isotopic data, age of the oldest hetrogen fragments rocks in the Takht-e-Soleyman continental crust gives ca. 2800 Ma, which is comparable with the ages from the Central Iran Micro-continent (ca. 2400 Ma). The regional metamorphism of the basement rocks in the Takht-e-Soleyman complex occurred during compressional regimes related to the Katangan Orogeny corresponding to the Precambrian. Partial melting of the metamorphic rocks has been occurred during Oligocene to Miocene corresponding to the final continental collision of the Neotethys ocean. Migmatites of the Takht-e-Soleyman complex are formed in this regard.
Original Research Paper
Monireh Kheirkhah
Abstract
Many centres within Iran are Plio-Quaternary in age and so formed 10s of millions of years after initial Arabia-Eurasian collision. Both composite volcanoes and lava fields present from Anatolia to eastern Iran. Basaltic rocks from Maku in the northwest Azerbaijanprovince of Iran are part of a widespread ...
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Many centres within Iran are Plio-Quaternary in age and so formed 10s of millions of years after initial Arabia-Eurasian collision. Both composite volcanoes and lava fields present from Anatolia to eastern Iran. Basaltic rocks from Maku in the northwest Azerbaijanprovince of Iran are part of a widespread series of Pliocene-Quaternary mantle-derived magmas erupted within the Turkish-Iranian orogenic plateau. A wide range of compositions has already been identified. Rock types span the range from primitive basalts to rhyolites with rare potassic and ultrapotassic lavas. Therefore, detail petrological studies and age dating on the Quaternary volcanism in NW of Iran, on the eastern of this plateau are very important. This paper presents new 40Ar/39Ar ages for lavas in the northwest Iran and compare them with the other young volcanoes, within the eastern Turkey (Anatolia); for example, Ararat (Agri Dagi), Tendürek and YigitDagi. These young volcanoes were erupted some of lava flows and were covered a big amounts of basaltic materials in eastern Turkey and also from N-Maku to Salmas and western of Urumieh lake (~200 km) during a short time in the Quaternary. This young basic to intermediate rocks are generated from the Ararat, Tendürek and YigitDagi. The variations in the lava chemistry of the Quaternary volcanic rocks indicate a geochemical progression from calcalkaline to more alkaline compositions in time and a spatial shift from north (Maku samples) to south ( Salmas samples) towards the Arabian plate. These lavas were erupted from a thick crust and thin mantle lithosphere within the Turkish-Iranian plateau, beginning at ~10 Ma.. The ranges dating of these basaltic lavas are, between ca. 1.87 and 0.40 Ma. These aging data indicate more exactly aging which were published in Turkey and the Yigit Dagi is determined ageing, which were not aging before. It will allow a complete picture of magmatism across an entire this part of Turkish-Iranian plateau by determination ages of the lava flows in northwest of Iran with comparing of the same flows in eastern Turkey
Original Research Paper
J Ghalamghash; S. Houshmand Manavi; M. Vousoughi Abedini
Abstract
Oshnavieh Plutonic Complex (OPC), hosted within the northernmost part of the Sanandaj- Sirjan zone, allows distinguishing three suites including diorite, granite and alkalisyenite-alkaligranite (AS-AG). Dioritic rocks formed from partial melting of enriched lithospheric mantle sources on base of minerlogical ...
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Oshnavieh Plutonic Complex (OPC), hosted within the northernmost part of the Sanandaj- Sirjan zone, allows distinguishing three suites including diorite, granite and alkalisyenite-alkaligranite (AS-AG). Dioritic rocks formed from partial melting of enriched lithospheric mantle sources on base of minerlogical and geochemistry. The granite suite is S type that formed from partial melting of metapelitic-greywacke source. The peraluminous A-type granite of AS-AG suite are generated by partial melting of quartzo-feldspatic source at high temperatures. According to the negative Nb, Ta and Ti anomaly in spider diagrams, and tectonic discrimination diagram of Rb-(Y+Nb), the diorite suite formed in active continental margin (VAG) environment. According to the diorite’s formed environment and simultaneously formed granite in 100 M.a., OPC seems to have formed by northeastward subduction of Neo-tethyan oceanic crust under the Iranian continental crust. Following intrusion and setting of mafic magma into the crust, partial melting of pelitic-greywacke, resulted from heating by intrusion of the mafic magma, produced the granitic magma. After 20 Ma the AS-AG suite formed from melting of quartzo-feldspatic rocks of lower crust, probably by heating of mafic magma and/or in relaxation period of subduction and emplaced in the continental volcanic arc.
