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آزاده ملک
زاده
author
محمد حسن
کریم¬پور
author
محمدرضا حیدریان
شهری
author
text
article
2006
per
Taknar Polymetal massive sulfide deposit is located at 28 km NW of Bardaskan within the Taknar inlier zone bordered with Doruneh and Taknar (Rivash) faults. Mineralization is dominantly hosted in Ordovician schists and has been dissected and displaced. The purpose of this research is to investigate and propose an appropriate geophysical exploration method for detecting new covered massive sulfide in the Taknar formation. Total Magnetic Intensity (TMI) was measured on a total of 10 survey lines in 300 points on Tak I, II and IV. This ground magnetic data showed very character-istic magnetic anomalies over surface mineralization on Tak I and II. Magnetic anomalies similar to Tak-I and II were observed in areas of Tak IV where mineralization is not seen on the surface. Mineral-ogical studies of samples taken from surface and old underground tunnel in Tak I and II showed variable amounts (5% to 65%) of magnetite along with sulfide mineralization. Country rock associated with mineralization has no magnetite. Measured mag-netic susceptibilities over schist samples as host rock in comparison with mineralized samples showed that the former is 1000 times weaker than the latter. This contrast is 10000 times between the massive part of mineralization and the country rock. Consequently there is a direct relation between magnetic anomaly and mineralization. Therefore, the strong contrast between the amount of magnetite in the deposit and host rock makes Taknar mineralization an ideal target for magnetic method. Quantitative interpretation of measured magnetic anomalies on Tak I assumeing zero remnant com-ponent, constraining the depth to the top of the causative body to the surface on the basis of field evidence and susceptibility is constrained to the average range of the measured samples showed that the depth of the source extends to 147 meter. Comparison of magnetic anomalies on Tak I obtained from this research with the previous work of reported IP showed that these two anomalies are spatially coincident, but the former is larger in ex-tension and amplitude than the latter. It is concluded that magnetic method is more effective and less expensive than other geophysical methods for dis-covery of similar massive sulfide mineralization in the Taknar zone.
Journal of Science,University of Tehran(not publish)
پرديس علوم
32
v.
1
no.
2006
https://jos.ut.ac.ir/article_16904_a35fe79ee90441c6fc6742d9f4e58830.pdf
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داریوش
اسماعیلی
author
مریم
شیبی
author
علی
کنعانیان
author
text
article
2006
per
On the basis of field observations, petrographic evidences and chemical data two types of sodic-calcic and potassic alterations have been identified in the center and margin of the Panj-kuh intrusive body, respectively. Development of albitization on the corner of plagioclase crystals, presence of albite with chess board twining, scapolitization of plagio-clase, high sphene and apatite content comparing with fresh igneous protolith and a general absence of magnetite are the most important evidences of sodic-calcic alterations in monzonitic rocks. Potassic alteration is defined by the presence of the shreddy aggregates of hydrothermal biotite and replacement of plagioclase by K-feldspar. Some elements such as Na2O, CaO, MgO, TiO2, P2O5, Sr, V and Sc are increased in sodic - calcic alteration at the same time as K2O, FeO?, Ba, Zr and Rb show decrease, whereas, potassic alteration show reverse trends. These evidences indicate that some elements such as Fe, K, and so on, leached from sodic-calcic zone and transported to the potassic zone by hydrothermal fluids.
Journal of Science,University of Tehran(not publish)
پرديس علوم
32
v.
1
no.
2006
https://jos.ut.ac.ir/article_16905_f8d484a8422e0ed29aeea024f3cc9106.pdf
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مریم معتمد
الشریعتی
author
کاظم سید
امامی
author
علی
اصغرآریایی
author
text
article
2006
per
Two stratigraphic sections in the Chaman-Bid Formation east of Mashhad have been measured and their ammonite fauna studied. These comprise 11 taxa coming from Narband and Radar sections. Based on ammonites the stratigraphic range of the Chaman-Bid Formation at Narband section is Bathonian to Oxfordian and at Radar section late Bajocian to Callovian. The ammonite fauna cor-responds more or less to those reported from Alborz and Central Iran, which indicates that the basins of Koppeh-Dagh, North and Central Iran were con-nected to each other. The studied ammonite fauna shows close relations to the same-aged ammonites of Europe, especially to the Sub-Mediterranean Province.
Journal of Science,University of Tehran(not publish)
پرديس علوم
32
v.
1
no.
2006
https://jos.ut.ac.ir/article_16906_13850888deb4e83346f21d216aa20a0c.pdf
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محمد
رهگشای
author
هادی شفائی
مقدم
author
ایمان
منصف
author
text
article
2006
per
The Nain ophiolitic massif, in the north of Nain town, consisted in lhezolitic-gabbroic (pegmatitic) bodies. Harzburgites, amphibolites, isotropic gab-bros, pillow lavas, gabbroic sills and dikes, pyroxenitic dikes, wherlitic dikes and gabbroic im-pregnations are also found. The crustal sequence is thin and is composed of limited volumes of pillow lavas and isotropic gabbros that gradually terminate into pelagic limestones and cherts in the upper levels. Amphibolites can be divided into garnet amphibolites with hornblende lineation, amphibolite mylonites with amphibole stretched lineation and non-foliated massive amphibolites. The other meta-morphosed units are spillites that include spillitized pillow lavas, diabases, isotropic gabbros and tuffites-tuffitic sandstones. Meta-gabbros associated with meta-peridotites and serpentinites are the abundant metamorphosed units of this massif. Pegmatitic gabbros are uplifted as melt mush in which the high plastically deformed clinopyroxenes can corroborate this hypothesis. Wherlitic dikes show shear or stress localization in the shear zones. The higher values of Cr and MgO# in isotropic gabbros than in basaltic rocks represent the equili-brium of gabbros with upper mantle peridotites. The clutter and fragmentation of this massif, also the thin crustal sequence, the volumetric serpentinites with intermingled exotic blocks of limestone, the heterogeneous plastic behavior of deformed minerals in mantle sequence and other factors demonstrate the derivation of this massif from the paleo-transform fault. We consider that this paleo-transform fault belongs to a slow spreading oceanic ridge.
Journal of Science,University of Tehran(not publish)
پرديس علوم
32
v.
1
no.
2006
https://jos.ut.ac.ir/article_16907_38f249eaa5e0f672233aee1365874525.pdf
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غلامرضا
خانلری
author
محمد
ملکی
author
text
article
2006
per
This paper presents the results of engineering geology and geotechnical studies in the Hamadan city. The methodology of this research work was getting data from geotechnical reports of the previous works and engineering geology studies, which have been done by authors. This is the first geotechnical report from the area, which has an overall view to the soils profile and foundation of the Hamadan city. In order to study quaternary non- cemented alluvials in this area, a South-North section with a length of 14 Km from Hamadan Plain was chosen. This section started from Dareh-Moradbeig to the end of Hamadan Airport. Based on the field and laboratory studies, conditions and texture of the alluvial and foundation of Hamadan city were considered. As a result, non-cemented alluvial in this area were studied in details and a geotechnical profile of the soils in this section was prepared. Results of this research work as a geotechnical profile of soil and foundation of Hamadan city can be used for engineering constructions in the study area. It should be noted that, this profile is introduced from the study area for the first time.
Journal of Science,University of Tehran(not publish)
پرديس علوم
32
v.
1
no.
2006
https://jos.ut.ac.ir/article_16908_1309aa4b4a1fa8ab15ac2a031e618384.pdf
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علی
اسماعیلی
author
حمید رضا سیاه
کوهی
author
text
article
2006
per
The theoretical best-possible resolution can be predicted using Beylkin’s formula. This formula gives answers to the effect on resolution of frequency, aperture, offset, and acquisition geo-metry. In this paper, for each 3-D single-fold data set a spatial wavelet is obtained from migration of an event that attributed to diffraction. Then the width of the spatial wavelet is compared to the resolution predicted by Beylkin’s formula. The measured widths confirmed the theoretical predict-tions (i.e. zero-offset data produces the best possible resolution; 3-D shot records produces the worst resolution, and common-offset gathers and cross-spreads producing the intermediate resolution. It is shown that the effects of sampling and fold cannot be derived directly from Beylkin’s formula; these effects are analyzed by looking at the migration noise rather than width of the spatial wavelet. Our results indicated that random coarse sampling may produce somewhat less migration noise than regular coarse sampling, though it cannot be as good as regular dense sampling. Generally speaking, in-creasing fold does not improve the theoretically best possible resolution. However, as noise always has a detrimental effect on the resolvability of events, fold by reducing noise will improve resolution in practice. Required algorithms were written by authors in MATLAB environment
Journal of Science,University of Tehran(not publish)
پرديس علوم
32
v.
1
no.
2006
https://jos.ut.ac.ir/article_16909_0dcd09be9b7b4443259c0210652eb2a9.pdf
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علی
کنعانیان
author
محبوبه نظری
وانانی
author
محسن
الیاسی
author
text
article
2006
per
The Salafchegan quartz diorite intrusion (Aleh Mountain) has intruded the sandy-limestone and sandstone of the Upper Red Formation as a con-cordant pluton and has metamorphed its country rocks slightly. The gentle dip of the sedimentary layering of country rocks suddenly increases near the pluton contact to a vertical position. This body has a circular shape, composed of quartz diorite and structurally could be divided into outer and central parts. While the outer part, with 500 meter thick-ness, shows alternation of leucocratic and melano-cratic layers, the central part has a massive outcrop. Both outer and central parts of this pluton show porphyritic texture typical of subvolcanic rocks. Moreover, the absence of ductile deformation within contact metamorphic aureoles, the presence of re-verse faults surrounding the intrusion, the occur-rence of concentric layering in the outer parts of the pluton, and the existence of magmatic foliation parallel to the contact zone in the outer dioritic layers could demonstrate ballooning mechanism in the Salafchegan intrusion. Accordingly, this pluton emplaced by ballooning mechanism due to repeated forceful injections of magma into an expanding shallow magma chamber, in the upper crust.
Journal of Science,University of Tehran(not publish)
پرديس علوم
32
v.
1
no.
2006
https://jos.ut.ac.ir/article_16910_61a5c3ac702b8e750bf79b678b9078a2.pdf
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محمد
محجل
author
محمد ولی ولی
زاده
author
فرزانه
مقدم
author
text
article
2006
per
A 2.5×10 km body of NE-trending mylonitic granite is exposed north of Aliabad-e-Damag, 35 km south of Hamadan. Mylonite and the surrounding schists have concordant fabrics parallel to the dominant foliation in the region. Structural and fabric analysis suggests deformation in a dextral strike-slip shear zone. The strong deformation and associated low grade metamorphism were coeval with plastic intrusion and continued to the end of crystallization. The granite has a retrograde thermal effect on the surrounding metamorphic rocks. Sigmoidal geo-metry of the large Hamadan pluton and the position of the dextral shear zone at the southeastern part of this system indicate the significance of dextral transpression tectonic in this region of the Sanandaj-Sirjan zone and rotation of the shear fractures in emplacement of the Aliabade-e-Damag pluton and subsequent intrusion of the Hamadan batholith
Journal of Science,University of Tehran(not publish)
پرديس علوم
32
v.
1
no.
2006
https://jos.ut.ac.ir/article_16911_057fae180e6ccb2b2b2823668d3eaae1.pdf
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محمدرضا
وزیری
author
محمد
داستانپور
author
اعظم
ماهانیپور
author
احمد
عرب
author
text
article
2006
per
The Mid-Cretaceous succession in west of Kerman city is represented by distinctive, correlatable green marls rich in macro and microfossils. The marls can be assigned an Upper Albian to Lower Cenomanian age based on the associated macrofossils assem-blage, which is dominated, by molluscs and echinoids. Six species of echinoids are described all of which are new records for the region. Pliotoxaster sp. together with Exogyra spp. Do-minates macrofauna assemblage. Many of the taxa have previously been reported from Oman, Egypt and Jordan. The fossil assemblage indicates a favorable condition during deposition of the green marls.
Journal of Science,University of Tehran(not publish)
پرديس علوم
32
v.
1
no.
2006
https://jos.ut.ac.ir/article_16912_3dd9a692bfa56d640a709e6288bb4d93.pdf
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علی
یساقی
author
زینب
داوودی
author
text
article
2006
per
The area of study is located in NW of Zagros fold-thrust Belt, between Kazerun and Balarud faults (Dezful zone). This part of the belt shows a complex structure, is affected by subsurface lineaments possibly during late Alpine orogeny. Detail assess-ment of landsat images together with geomagnetic and earthquake data resulted in identification of subsurface shear-transverse faults.
Journal of Science,University of Tehran(not publish)
پرديس علوم
32
v.
1
no.
2006
https://jos.ut.ac.ir/article_16913_38ac82f00ac814a1eb1e3b0595aca9f9.pdf
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ابراهیم قاسمی
نژاد
author
الهه
زارعی
author
text
article
2006
per
The foraminiferal content of the Gurpi Formation at the type section in Anbar Sefid Valley NE of Lali city in Masjed Soliman was studied. The recorded foraminifera indicate an age of Late Paleocene for the upper boundary of the formation that turns to purple sandy and silty shales at the base of the Pabdeh Formation. The K/T boundary lies 57m below the purple key layers. The Study of the foraminifera at the K/T boundary demonstrates that the specialist polytaxic species with large size and complex morphology (such as pseudotextularids, rugoglobigerinids and globotruncanids) which were sensitive to changes in environmental condition disappeared ,while generalist oligotaxic species with small size, simple morphology and fine shells (such as hedbergellids and heterohelicids) became domi-nant. As the changes in fauna's composition are usually raised from ecological factors, thus the changes in the most important ecological factors such as salinity, temperature, Oxygen, PH, sub-surface currents and nutrient supply have been evaluated to interpret the changes in faunal composition. Definite decreases in temperature, salinity, Oxygen amount and pH and increase in sea current and nutrient amount have been concluded as the most important factors effecting faunal changes across the K/T boundary. These changes in ecological factors might have been results of an increase in upwelling currents generated in Early Paleocene preceded by a regression at the end of Cretaceous.
Journal of Science,University of Tehran(not publish)
پرديس علوم
32
v.
1
no.
2006
https://jos.ut.ac.ir/article_16914_8c9d0cb873e77ffc605389ed019e4ef6.pdf
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Kamali
M.R
author
Fathi Mobarakabad
A
author
Mohsenian
E.
author
محمدرضا
کمالی
author
افشین فتحی مبارک
آباد
author
الهام
محسنیان
author
text
article
2006
per
Dezful Embayment located in Southwest of Iran is one of the most potential areas for exploration and development of hydrocarbon reservoirs in the world. There are several source rock units with different geological ages. Burial and thermal history modeling was performed to determine timing of hydrocarbon generation in the Pabdeh source rock in Dezful Embayment. Geology and sequence stratigraphic analysis of borehole data including drill-cuttings provided fundamental constraints for burial history reconstruction. In addition, estimates of exhumation from log-derived compaction data provide key insight into depositional patterns. One-dimensional and two-dimensional models of thermal evolution were derived from the burial history and calibrated with vitrinite reflectance, thermal conductivity, surface and bottom-hole temperature measurements, as well as with paleoclimate data. The resulting thermal history models were combined with the measured geochemical parameters in order to determine the timing of hydrocarbon generation for the candidate source rock (Pabdeh Formation). Results were compiled in maps and cross-sections representing multiple stages of basin evolution. Most hydrocarbon generation in the Dezful Embayment generally took place in Kazhdumi Formation and partly in Pabdeh Formation. The Pabdeh Formation is the most youngest source rock in Dezful Embayment with type II and a mixture of type II and III Kerogens and has reached oil generation at most parts of the Dezful Embayment. Higher amounts of hydrocarbon were generated at deep and central part related to higher maturity levels. Based on thermal maturity modeling, Pabdeh Formation is early mature to mid mature.
Journal of Science,University of Tehran(not publish)
پرديس علوم
32
v.
1
no.
2006
https://jos.ut.ac.ir/article_16915_e7938ea94ff52c976fe36c87709640c3.pdf
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M.
Ghavidel-syooki
author
محمد قویدل
سیوکی
author
text
article
2006
per
A total of 66 surface samples from the Mila, Lashkarak and Ghelli Formations of Kuh-e-Kharbash (near Deh-Molla) were paleontologically investigated, to determine the geological age of the rock units. This study was also undertaken to assess the palaeogeographic relationships of the study area to Southern and Northern Hemispheres during the Palaeozoic interval represented by these Formations. Fifty two palynomorphs (51 acritarchs and one algal body) were recorded, which permit the recognition of six acritarch-based biostratigraphic zones. Acritarch assemblage zone I is Late Cambrian in age and occurs in the upper part of the Mila Formation. Assemblages zones II through IV are present in the Lashkarak Formation and suggest Lower Ordovician (Tremadoc-Arenig). Assemblage zones V and VI are present in the Ghelli Formation and indicate Upper Ordovician (Caradoc-Ashgill) for this Formation. Based on palaeontological data, two hiatuses are present within the studied stratigraphical column. The first hiatus occurs between the Lashkarak and Ghelli Formations and encompasses the Middle Ordovician strata .The second hiatus is present between the Ghelli and Geirud Formations and includes the whole Silurian and Lower-Middle Devonian deposits. The above- mentioned hiatuses possibly correspond to the Caledonian Orogeny. Diverse acritarch assemblages in the Late Cambrian (Mila Formation), Lower and Upper Ordovician (Lashkarak and Ghelli Formations) indicate that a marine environment through the entire succession. Comparison of the acritarch recorded taxa with those reported from other parts of the world, suggests that the Alborz Mountain Ranges have been part of peri-Gondwanan palaeoprovince during the Ordovician.
Journal of Science,University of Tehran(not publish)
پرديس علوم
32
v.
1
no.
2006
https://jos.ut.ac.ir/article_16916_121e80866f853300dfc6d0111fb20681.pdf
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Bagheri
A.M
author
Biranvand
B.
author
علی محمد
باقری
author
بیژن
بیرانوند
author
text
article
2006
per
Journal of Science,University of Tehran(not publish)
پرديس علوم
32
v.
1
no.
2006
https://jos.ut.ac.ir/article_16917_560d0c58e9d97527aa5a9fff8c94ca35.pdf
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A.R.
Ashouri
author
علیرضا
عاشوری
author
text
article
2006
per
Icriodus and Polygnathus faunas from the Late Devonian of the Tabas region of eastern Iran, and from the Middle-Late Devonian of the Alborz Mountains, northern Iran, are documented. Twenty three species and/or subspecies of Icriodus and 33 of Polygnathus are described and illustrated. Among them are five new species of Icriodus: Ic. housei, Ic. talenti, Ic. bultyncki, Ic. walliseri and Ic. jafariani.
Journal of Science,University of Tehran(not publish)
پرديس علوم
32
v.
1
no.
2006
https://jos.ut.ac.ir/article_16918_7c00938fcd63d2e41141265d3d7b9656.pdf
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V.
Tavakoli
author
A.
Amini
author
text
article
2006
per
Reservoir zonation is the most important job in oil industry which dominantly relies on the major properties of rocks. Fundamental properties of rocks are usually understood by their detailed description in the field (lithofacies analysis) and laboratory (petrofacies analysis). The facies (lithofacies and petrofacies) determination in most subsurface studies is impractical, due to lack of cores and cuttings. In such situations, where the wire line logs are the only data available, the logfacies or electrofacies are determined instead. Using multivariate cluster analysis, in this study practiced the logfacies determination on the Asmari Formation of Marun Field by programming a new algorithm with MATLAB software. The study is carried out on the logs of a well in which the Asmari Formation is fully cored. Determined logfacies are correlated with lithofacies defined on the cores and thin sections. Reliability of the procedure in logfacies determination is examined and an appropriate cut off level is defined for the cluster analysis. Result from this study is prepared to use in logfacies determination of the adjacent wells with no cores and cuttings.
Journal of Science,University of Tehran(not publish)
پرديس علوم
32
v.
1
no.
2006
https://jos.ut.ac.ir/article_16919_1ca7d85ff4f4404e7251ad06e800bf6a.pdf