نشریه علوم زمین
پیاپی 87 (بهار 1392)

The Dalichai Formation at Talu section, 24 kilometers NE of Damghan is studied Palynologically. The Middle Jurassic sediments with a thickness of 168 meters in this section contain grey to green marl and grey marly limestone. A total of 35 samples were collected systematically and 200 palynological sildes were prepared. Forty nine species of dinoflagellate cysts belonging to 30 genera were identified. A few fungal spores and foraminiferal test lining and spores and pollen grain were also recorded. Although, dinoflagellate species are abundant but all the species recorded were concentrated in lower parts of the section 0-110 meters). Two palynozones were identified; Cribroperidinium crispum Total Range Palynozone (Ccr), Dichadogonyaulax sellwoodii Interval palynozone (Dse). A local palynozone of Ctenidodinium combazii/Ctenidodinium ornatum ornatum Acme Zone were also established in the succession. An age of Bajocian – Late Callovian was proposed for the succession studied.

The breccia-hosted epithermal Ag-Au deposit of Chah Zard is located within an andesitic to rhyolitic volcanic complex in the central part of the Urumieh-Dokhtar magmatic belt. At this location, magmatic and hydrothermal activity was associated with local extensional tectonics, formed in the Dehshir-Baft strike-slip fault system. The host rocks of the volcanic complex consist of Eocene sedimentary and volcanic rocks covered by Miocene sedimentary rocks. LA-ICP-MS U–Pb zircon geochronology yields ages between 6.36±0.14 and 6.19±0.24 Ma, and a mean age of 6.23±0.16 Ma for magmatic activity at Chah Zard. Breccias and veins were formed during and after the waning stages of strong explosive eruption of magmatic-hydrothermal and phreatomagmatic brecciation events due to shallow emplacement of the rhyolite porphyry. Detailed systematic mapping leads to the recognition of three distinct breccia bodies: the volcaniclastic breccia with a dominantly clastic matrix, the gray polymict breccia with a greater proportion of hydrothermal cements, and the mono-polymict breccia with argillic groundmass matrix. The polymictic breccias generated bulk-mineable ore, whereas the volcaniclastic breccia is relatively impermeable and largely barren. Variable hydrothermal alteration occurs in outcrops, covering about 9 km2 at Chah Zard. Hydrothermal alteration assemblages are zoned around the breccias and veins, consisting of secondary quartz, illite, pyrite, adularia, chlorite, various carbonate minerals, and minor K-feldspar. Iron oxide-hydroxide, jarosite, gypsum, kaolinite, halloysite and rare alunite are the supergene alteration minerals replacing primary minerals, and filling the fractures and vugs. Precious metals occur with sulfide and sulfosalt minerals as disseminations in the veins and breccia cement. There is a progression from pyrite- dominated (stage 1) to pyrite-base metal sulfide and sulfosalt-dominated (stages 2 and 3) to base metal sulfide-dominated (stage 4) breccias and veins. Deposition of gangue minerals progressed from illite-quartz to quartz-adularia, carbonate and finally gypsum-dominated assemblages. Free gold occurs in stages 2 and 4, principally as intergrown with pyrite, quartz, chalcopyrite, galena, sphalerite, and Ag-rich tennantite-tetrahedrite; and also as inclusions in pyrite. The U-Pb zircon age of 6.19±0.24 Ma for emplacement of the rhyolitic magmas represents the maximum age of mineralization at Chah Zard. It may indicate that there was a previously unrecognized mineralization event in Urumieh-Dokhtar at this time.

Field relations and petrographical features, shows that formation of the metapelitic and carbonate rocks of Hamadan in Western Iran was poly-metamorphic. The intrusion of the Alvand Batholite (Jurassic age) into pelitic and calcareous host rocks has produced metamorphic rocks in the Cheshin area containing, sillimanite hornfels, marbles and calc-silicate rocks. Mineral assemblages in the metapelitic and calc-silicate rocks are different, peak metamorphic assemblages of these rocks respectively are garnet, biotite, staurolite, aluminosilicate minerals (kyanite/ sillimanite), muscovite and quartz but calc-silicate assemblage are garnet, diopside, wollastonite epidote and amphibole, which usually take place by contact metamorphism. Using multiple equilibria, temperature (~600-630 ºC), pressure (~2-4 kbar), and fluid composition (XCO2 as low as 0.17) have been calculated for the formation of the calc-silicated rocks. The results show good agreement with those from other metapelitic rocks. P-T results indicate that contact metamorphism conditions occur in pyroxene hornfels facies in this part of the Hamadan crust.

The Barika gold (and silver) rich-massive sulfide deposit is located 18 km east of Sardasht city, north western part of Sanandaj-Sirjan metamorphic zone. Rock units outcropped in this area are metamorphosed volcano sedimentary rocks in green schist facies, and include association of meta-andesite, meta tuffite, phyllite, and slate rocks. The Barika deposit is metamorphosed to greenschist facies, and underwent Barika shear zone- related deformation. The metamorphism/deformation events have superimposed on the synvolcanic stratiform ore and resulted in a variety of mineralogy and textures. Ore minerals in the deposit were originally composed of pyrite, sphalerite, galena, tetrahedrite- tenantite and stibnite which were deposited during synvolcanogenic hydrothermal activity. Gold probably was occurred as submicroscopic inclusions or invisible gold locked in pyrite and electrum in barite. Prograde metamorphism/deformation obliterated almost the sedimentary textures in the stratiform ore. The regional metamorphism have resulted in the development of granoblastic textures with triple junctions in pyrite which lead to migration of submicroscopic gold to the crystal boundary to form microscopic electrum. Shear zone - related deformation, lead to mobilization of metallic constituents and eventually reconcentrated them as visible electrums associated wَith sulfosalt minerals at microfractures and open spaces which have developed during the shearing deformation. Metamorphic/deformation remobilization was important in releasing refractory Au from sulfides and locally concentrating it in a recoverable form (electrum).

Iranian Azerbaijan is a region in Northwest of Iran where has large active deformation and seismicity. It is located between two orogeny, Zagros in the south and Lesser Caucasus in the north. In this research geological structures and tectonic stress state of area are studied to search connection the tectonic and neotectonic of Azerbaijan. In this study the analytical method of Angelir, 2002, is used to analising the stress tensors. Also his methods, 1984 and 2004, are used to separation of stresses. Firstly it is collected seismic and field data of faults and analyzing their stress states. Then 2nd order stress field of Azarbaijan microplate is reconstructed by stress separation analysis. Also remote sensing methods helps to study of imbricate structures in the northern and southern parts of Azarbaijan microplate. The stress analysis results in this study (by analytical method, for seismic and field data) shown there are two compressional stresses (NE-SW and NW-SE directions). First stress system by NE-SW directions cause developing of three tectonic grains as Arasbaran, Ahar (Goshe Dagh) and Bozkosh fold thrust belts. But the second one (NE-SE direction stress system) cause developing of thrusts in N-S direction. Reconstruction of first order stress in relation with the tectonic grains, and structures, reduced the tectonic model of Azerbaijan plateau. In this model the (East) Azerbaijan plateau is in collision with Lesser Caucasus in north, South Caspian basin in east, and Central Iranian block in south and west. In this way reconstructed compression induced the conter-clock wise rotation to the Azerbaijan plateau.

The aims of present study are investigation of endemic plants in Masjed-Daghi area introducing hyperaccumulator and indicator plants for gold and copper, and also describe the biogeochemical response pattern over a known mineralized site, namely the “Au- Cu” mineralization at Masjed-Daghi area. Masjed_Daghi is located in Jolfa sheet and it is underlain by Eocene flysch, andesite, trachyandesite, dacite, rhyodacite, Oligocene agglomerate and Quaternary deposits. Pervious researches reported copper porphyry mineralization in this area.Considering variety of vegetation in Jolfa and Masjed_Daghi, indicator plants for Cu, Pb and Zn mineralization in the study area were investigated. Mean metal contents (ppm) and mean biological absorption coefficients for Stachys inflata are: Cd 0.13- 1.18, Cu 14.8- 1.10, Pb 5.67- 0.52, Re 0.033- 4.4 and Zn 57.4- 2.50; for Artemisia sp.: Cd 0.373-1.40, Cu 22.06- 0.19, Pb 5.801- 0.12, Re 0.197- 97 and Zn 35.51- 0.48; for Moltkia coerulea: Cd 0.15- 5, Cu 24.6- 0.78, Pb 0.48- 0.06, Re 0.348- 116 and Zn 125.5- 9.65; for Astragalus sp.: Cd 0.033- 0.37, Cu 11.44- 0.21, Pb 0.513- 0.04, Re 0.089- 53 and Zn 21.8- 0.83; for Salvia sp.: Cd 0.047- 0.55, Cu 11.04- 0.46, Pb 2.6 0.19, Re 0.091- 19 and Zn 70.43- 3.42. This study presents that plants with high metal intake enabled us to obtain invaluable information about natural concentrations of chemical elements in the substrate, and to recognize new potential areas for mineral prospecting. In this study most of these plants have mean biological absorption coefficients exceeding or near to hyperaccumulating criterion >1 for most of the elements investigated. Most of the hyperaccumulator values belong to Stachys inflata and the indicating values belong to Stachys inflata, Artemisia sp., and Salvia sp.

The Early Triassic carbonates of Kangan Formation are major gas reservoirs in the Southwest of Iran and the northern Persian Gulf. Facies analyses of Kangan Formation led to recognition of 13 microfacies which are related to tidal flat, lagoon, shoal and open marine environments. Examination of vertical and lateral facies changes and thire comparison with their modernand ancient counterparts, all indicate that Kangan Formation were deposited in a shallow carbonate ramp platform similar to the present day Persian Gulf. The sequence stratigraphic studies showed that the Kangan Formation consists of two third order depositional sequences (in the A and B wells), each consisting of transgressive and highstand systems tracts. The lower boundary of the first sequence is a type 1 unconformity, but other boundaries are type 2 unconformity. Typical reservoir zone in the Kangan Formation is dominated in early highstand systems tract deposits and concentrated in shoal grainstone facies. However, in this paper, typical intervals such as sequence boundaries, maximum flooding surfaces, stacking patterns and system tracts were studied. Keywords: Kangan Formation, Early Triassic, Lithofacies, Microfacies, Sequence Stratigraphy.

The studied section is located west of Tabas (Rahdar Mountion) in the Kalmard Block. The newly named Chili formation, as the first rock unit of the Khan group consist mainly of arenacous limestone, limestone and dolomite and has disconformity contact with underlying lower carboniferous deposits (Padeh formation) and overlying late Yakhtashian-Early Murgabian (Sartakht formation) bauxite and laterite horizon,in this study 6 genus and 19 species of Fusulinids were recognized which could be grouped in two Biozones. The first biozone correspond to Perigondwania pamirensis Zone belonging to Late Sakmarian. The second one is comparable with Chalaroschwagerina vulgaris Zone of Early Yakhtashian age. The mentioned biozone is fairly comparable with Kalaktash assemblage already reported from Central Pamir,Karakorom, Afghanestan and south Tibet regions.

Due to its geographic position and located on the World earthquake belt; Iran is always under threat from earthquakes and several shakes are recorded every year all over the country. The most recent earthquake with 6.8 degree magnitude on the Richter scale hit the city of Bam in 2003 and caused large losses of human life and infrastructure. The 2003 Bam earthquake, with more than 30,000 casualties and 10,000 injuries, was the most Destructive earthquake in the current century in Iran. We aim to recognize the main reasons causing these deterioration problems. To this end, we first conceptualize thirteen physical-spatial factors. These factors are analyzed using fuzzy logic and IHPW (Inverse Hierarchy Process Weight) within Geographical Information System. We also attempt to identify the Correlation coefficient analyses between urban vulnerability and damage using Fuzzy logic and GIS. In statistics, correlation and dependence are any of a broad class of statistical relationships between two or more random variables or observed data values. With respect to the covariance between two variables (urban vulnerability map and damage post earthquake) the correlation coefficient is calculated 0.59. The results of the model as applied to the structures of the city of Bam illustrate that a fuzzy approach is a basic tool that can be used to identify urban vulnerability and damage post earthquake incident. Its application to the problem assists in unifying relevant theories and practices.

That in addition to playing an educational-scientific role, it causes to touristic development. In order to introduce and evaluate geotourism potential of Quaternary phenomena in Sedimentary basin of Gorgan Plain, this study is based upon library review, consideration of previous records in regional, zonal, and national scales, field operations and photographic documentation. The results show that 75% of geotourism phenomena are in pattern and indicator level and 40% are placed in zonal site from the value and importance of each geotourism phenomenon points of view, respectively. Due to climatic changes, variety of weathering processes, zonal erosion system (Caspian-Alborz) and sea level fluctuations during Quaternary and ancient eras, Gorgan Plain has unique geomorphic evidences and landforms and natural structures such as continental, and coasteal sand dune with various forms and compositions, loess materials and ancient hills, tectonic-erosion origin lakes, mud volcanoes, meanders, and Gorgan-Rud and Ghara-Su deltas. Diversity of geotouristic phenomena of Quaternary in Gorgan Plain is absolutely prominent on national and the whole Caspian Sea basin scales and it is convertible to a zonal scale geopark.

Trace fossils are abundant in the clastic succession throughout the Shirgesht Formation of Kalmard Block, Central Iran. At certain horizons there are beds full of Cruziana and Rusophycus. This study presents an evaluation of the arthropod ichnotaxa of the Cruziana and Rusophycus from the Ordovician succession Shirgesht Formation. Apart from the broad range inmorphology and size, Cruziana from Shirgesht Formation show higher behavioral diversity using food sources than has ever been documented in a single section. It consists of a straight, or gently curved, ploughed furrow usually a few centimetres across, which is divided lengthwise into two lobes, each of which is braided transversely by a series of scratches. These vary in arrangement and profile according to ichnospecies. Overall characteristics of recognized ichnospecies suggest that with the exception of C. semiplicata, the ichnofaunas contain all the members of the Cruziana rugosa Group throughout the clastic successions in Shirgesht Formation. It consists of the five members of C. rugosa, C. furcifera, C. goldfussi C. rouaulti and C. yini. The Shirgesht Formation material therefore indicates that these arthropod ichnofossil assemblages are suitable for Cruziana ichnostratigraphy in Shirgesht Formation. Accordingly, the present assemblage could represent the Early to middle Ordovician age. The arthropod traces also, occur with other biogenic sedimentary structures in a fine to medium grained sandstone with minor mudstone interbeds of the Shirgesht Formation. The substrate composition and ichnological evidence places the arthropod ichnofossil-rich unit in the Cruziana ichnofacies.

The Lower Cretaceous Shir-Kuh granitic batholith in central Iran intruded to the sandstones and shales of Nayband-Shemshak Formation. The batholith consists of three main granodioritic, monzogranitic and leucogranitic units. The anisotropy of magnetic susceptibility technique (AMS) was used for distinguishing relative chronology between emplacements of the magma batches in Shir-Kuh batholith. The rather low susceptibility magnitudes (Km<400μSI) call for the dominance of biotite as magnetic carriers, considered as typical of the so-called paramagnetic granites and there is a first-order correlation between magnetic susceptibility and rock-type. The various magnetic data (magnetic lineation and foliation maps, K, P and T parameters), complemented by field and microstractural observations, allow us to propose that the two main feeders of the batholith represent tension gashes that formed at the base of the brittle crust and served as conduits for the magma. The progressive differentiation of magmas associated with petrographic zoning of the Shir Kuh Batholith is therefore viewed as progressive opening and infilling of the En echelon gashes more or less parallel to the regional dextral shear zone. The filling started with granodiorites, followed with monzogranites and ended with leucogranites and resulted in the construction of the batholith.

The aim of this paper is the assessment of the effects of seismic loads on the earth dam for design purposes by developed graphical user interface computer software by authors. The Ghohoord earth dam in Hamedan province which is located in a high seismic zone named as Sanandaj-Sirdjan seismotectonic province is used as a case study. A seismic geotechnical based method of analysis was used by employing a designed and developed computer code, with earthquake record analysis for evaluation of 1D site response, thereby saving computational time and increase the accuracy of results. The records were determined based on Building and Housing Research Center web site of Iran. This method and its modeling is being implemented using the combination of several computer codes with MATLAB programming tool. Data used in this study are include of geologic maps, an elevation model, borehole data, shear wave velocities and ground motion records. The obtained results showed the ability and capability of the generated code for reaching to the aim of paper. The ultimate results were indicating the reliability and capability of generated code in seismic site response analysis.

The Dare Anjir and Fariman complexes in NE of Iran are considered as remnants. These complexes considering were located close to Palaeotethys suture zone, and thus they record its structural evolution. considering structural and petrological evidences and against previous opinions that considered Fariman complex as an accretionary wedge, these complexes seem to be remnants of a magmatic arc that formed as a result of subduction of the Palaeotethys beneath Turan plate in Permian-Triassic. Fariman complex may be divided into upper and lower parts. At least two deformation phases may be recognized in upper part of the Fariman complex. second deformation phase caused creation fault propagation folds, and probably was coeval with main deformation phase of Eo-Cimmerian that affected Aghdarband basin. Deformation style in Fariman and DareAnjir complex is compatible with strain partitioning proposed for Aghdarband transpressional zone as a result of oblique convergence between Iran and Turan during Eo-Cimmerian event.

In order to study the biostratigraphy and palaeoecology of the Maestichtian deposits (Tarbur and Gurpi formations) in High Zagros, Gardbishe section in south of Borojen was selected. The Tarbur deposits in this region are mainly composed of carbonate and clastic a rock which has been overlaind by Gurpi Formation. The lower contact of this formation is lower red unit as conformable contact. The Gurpi Formation is lithologically composed of marl which has been overlaind as a disconformable contact by Shahbazan dolomites. The biostratigrphic data based on benthic and planktonic foraminifera and rudists represents the late Maestrichtian age for the section. Two biozones were identified in Maestrichtian deposits including: Omphalocyclus-Loftusia assemblage zone, Contusatruncana contusa-Recemiguembelina fructicasa zone. In general, the suitable environmental conditions for diversity, frequency and increase in size of some fossils such as Loftusia and in the absence of some other fossils such as Orbitoides and Lepidorbitoides in this region can be related to augmentation of nutrients and entering the detrital and silica sediments due to river injection and runoff and consequently to the eutrophic conditions formed in the basin.

Grade control and ore quality determination has always been considered a challenging task for geologists and mining engineers. Ore quality is dependent on various factors such as size and geometry of a deposit, geological disturbances, and texture and ore mineralogical composition. Determination of factors which control ore grade and prediction of a suitable area are very important in terms of economics and productivity of mining operations. This study has tried to develop spatial and statistical analyses for evaluating ore quality and recognition of ore grade influencing factors at Jajarm Bauxite Mine. Through incorporating topographic, geologic and geochemical data, the effects of faults, elevation and depth on the ore grade and module (wt% Al2O3/Wt% SiO2 ratio) has been assessed. The results showed that the amounts of Al2O3 and module increased as we get closer to the faults. Furthermore, there was not any effect of faults type and strike on grade and module. A negative correlation between both elevation and depth with the amounts of Al2O3 and module indicates ore quality improvement in lowlands and shallow depths. Thus, the combination of geographic information system (GIS) methods and multivariate statistical analyses might be more efficient in geo-spatial assessments.

The Golbaf area in Kerman province (SE Iran) has experienced five earthquake of Mw 5.4 7.1 between 1981 and 1998. Occurrences of these earthquakes in seventeen years time interval indicate that occurrences of earthquakes on the Golbaf (Gowk) fault system have a clustering model. In this study we use morphotectonical and paleoseismological evidences to show that seismic behavior of this fault in the past has a clustering model in some time intervals. For this purpose at the first near-field morphotectonical analysis performed using real time kinematics (RTK) GPS survey and digital elevation model and digital topographic map of surface ruptures of past earthquake prepared with high accuracy. Detail analyzing of this model indicate that the rake angle of Golbaf fault is about 10 degree. This result is in agreement with rake angle calculated from seismological methods and also observations of slickenlines on rupture plans that show dominant right lateral strike slip mechanism of the Golbaf fault. According to the paleoseismological investigations which were associated with digging a trench perpendicular to the Golbaf fault indentified four Paleoearthquake with magnitudes of Mw>6.6. By using some of empirical relationship, maximum magnitude of oldest Paleoearthquake calculated about Mw 8.2 that it is unbelievable and show similar to today that occurred five earthquake during short time interval on this fault, occurrence of earthquake in the past on some of time interval have clustering model so that occurred a lot of big earthquake in short time interval that there was not enough opportunity for sedimentation and record of evidences of this earthquake separately.

Mantle sequences exposed in west of Fannuj- Maskutan area comprise of lherzolite and porphyroclastic cpx-bearing harzburgite in the lower part and recrystallized fine-grained lherzolite with chromitite lenses in the upper parts of the sequence. Petrography studies and microprobe data show evidence of melt/peridotite interactions, post-melting processes and subsolidus interactions associated with the appearance of two generations of deformed primary pyroxene-olivine and fine-grained pyroxene-olivine amphibole neoblasts. Second generation of minerals formed as inclusion, interstitial and fine-grained. These two groups of minerals have different geochemical characteristics, i.e., the first group are comparable with abyssal peridotites and the second group are comparable to suprasubduction peridotites. Therefore, the chemical compositions of different generations of minerals show different petrogenesis for ultramafic rocks of the Fannuj- Maskutan ophiolitie complex. Interpretation of whole rock chemical data indicate that these rocks have a depleted MORB mantle source which underwent 5-15% partial melting. Rare earth element patterns normalized with chondrite standard values and compared with patterns of depleted MORB mantle (DMM), indicate enrichment in LREE/MREE ration and show U-shape patterns. Thus, the peridotites of the Fannuj-Maskutan ophiolitie have experienced multistage evolution and show characteristics of abyssal environment to suprasubduction zone. It might be said that transition from abyssal environment to suprasubduction has been affected by fluids derived from the subducted slab.

In order to provide a strategic plan for any sector, the internal factors, the required timeframe and the related visions and policies should be studied. Strategy development requires a realistic view of the surrounding environment, in which the competition and challenges rule the future of any organization. The outside world continuously, provides opportunities and imposes threats for the companies and organizations. For the organizations to be successful, they should optimize the existing opportunities and advert the threats to opportunities. This paper focuses on the opportunities and threats within the mining sector. Having analyzed and interpreted the existing conditions, the opportunities, threats and in general, the weaknesses of the mine sector are recognized and the strategic planning for achieving the targets and visions will be prepared.

Calcareous Nannofossils are good tool for biostratigraphy, especially in the Late Cretaceous. With respect to this and due to the lack of any precise paleontological study, the calcareous nannofossils of Ilam and Gurpi Formations were investigated in the Southwestern Sarvestan. These Formations consists of marl, clay limestone and shale. In this study, for the first time, 14 families, 22 genera and 39 species of nannofossils were identified. Based on the information obtained on nannofossils, the section is aged at Late Coniacian-Early Santonian to Early Maastrichtian corresponding to CC14-CC24 zones (Sissingh, 1977).

The results of studies of Electronic Microscope (SEM) on the samples which came out of the autoclave, which has been under hydrothermal in Karaj, Sazand and was diagnosed with sedimentary genes. Measures, such as selective sampling of Zeolit minerals and XRF & XRD (broken samples), analysis and supplying thin pieces and preparing samples, washing with KOH & NaOH & Ammonia liquids, using magnetic stirring machines, autoclave, furnace and drier, and creating hydrothermal condition was done and finally, with electronic microscope and variable magnification, we watch an amount of synthesized crystals without breaking them, in order to picturing the crystals, type and form of them and point analysis via ED X-ray to elemental analysis. The results of the studies shows confirmation of changes to accomplished phase from natural Zeolit of Damavand and synthesis of Zeolit minerals that considering using changes of natural Zeolit structure of Damavand and synthesis of new minerals, with 70 years artificial Zeolits synthesis in labs, as a technical and economical justification for an international research, is very important.