List of Articles گچ

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  1 - Geochemistry, microfacies and depositional environment of Eocene Deposit in Gach Mountain, in SE Lar Area
  محمد حسين  آدابي
  The Jahrum Formation in Gach Mountain, located near village of Chahar Berkeh, in 30 Km of south- east of Lar City, south- west of Iran (Zagros Basin). This formation with the total thickness of 404.5 m consists of dolomite, calcareous dolomite and limestone. This form More

  The Jahrum Formation in Gach Mountain, located near village of Chahar Berkeh, in 30 Km of south- east of Lar City, south- west of Iran (Zagros Basin). This formation with the total thickness of 404.5 m consists of dolomite, calcareous dolomite and limestone. This formation overlies the Sachun Formation. The Asmari Formation with the total thickness of 44.5 m consists of limestone and marly limestone, and covered by evaporite deposits of the Gachsaran Formation. The age of the Jahrum Formation is Late Paleocene to Late Eocene. Eocene deposit in Gach Mountain, based on different facies, foraminifera and other skeletal and non skeletal grains, 7 microfacies were recognized. These microfacies deposited in a carbonates ramp environment with ooid shoal deposits. Analysis of 30 samples of limestones and dolomites for major and minor elements (Ca, Mg, Fe, Mn, Na, and Sr) and oxygen and carbon isotope values were used for carbonate mineralogy, types of dolomites, and diagenetic system. This study indicates that Jahrum carbonates were deposited in a shallow warm water tropical environment and original carbonate mineralogy was aragonite. These carbonates were affected by close to semi close diagenetic system with low water/rock interaction. Diagenetic trend in limestones and dolomite, based on oxygen and carbon isotope variations, shows a burial diagenesis with the presence of origanic matter. Temperature calculation based on heaviest oxygen isotope values (-3.32% PDB) of micrite and δw of Eocene seawater of - 0.85 SMOW, indicate that very shallow burial temperature was around 23˚C. Sequence stratigraphic studies, shows that two depositional sequences, consisting of transgrassive system tract (TST) and highstand system tract (HST). This sequences, shows third order type, with sequence boundaries (SB2). Maximum flooding surface in the Jahrum Formation was determined based on different facies and variation of isotope values. Manuscript profile
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  2 - The hydrogeological water balance of Barm-e-Shour wetland in the Haftkel city, Khuzestan province
  Farzad Akbari rahim bagheri Arash Nadri
  Wetlands are the most important and yet vulnerable environmental resources which are vital as water resources to agriculture, springs, ground water recharge and ecology. Therefore, the management and restoration of the wetlands are of great importance and require hydrog More

  Wetlands are the most important and yet vulnerable environmental resources which are vital as water resources to agriculture, springs, ground water recharge and ecology. Therefore, the management and restoration of the wetlands are of great importance and require hydrogeological scrutiny. Barm-e-Shour is one of the most important wetlands in Khuzestan province and is utilized for drinking and agricultural purposes. The wetland is situated on Gachsaran evaporate formation. There are no permanent surface inflows, yet the wetland maintains a steady reservoir, despite the recent drought and water supply limitations. Water and recharge origin which require calculating hydrogeological balance have not been studied so far. To achieve this goal, the iso-depth map, annual water level fluctuation, catchment area and different parameters of water balance were determined. The maximum depth during the dry season was about 3 meters. According to hydrogeological surveys the water balance was positive so that the yearly inflow of water was about 10912 m3 indicating the main role of ground water in wetland recharge. Considering the karst development and isotopic results, carbonates of the Asmari anticline is the most probable source of Barm-e-Shour wetland water. Manuscript profile
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  3 - The effect of the Gachsaran mobile formation on folding style and tectonic evolution of the Rag-e- Sefid anticline in the southern Dezful Embayment
  Mehdi Yosefi Seyd Morteza Moussavi Mohammad Mahdi Khatib
  Plastic behavior and significant thickness of the Gachsaran incompetence formation on top of middle carbonate units in the sedimentary sequence of the southern Dezful Embayment led to the emergence of different styles of folding above and below of this formation. So tha More

  Plastic behavior and significant thickness of the Gachsaran incompetence formation on top of middle carbonate units in the sedimentary sequence of the southern Dezful Embayment led to the emergence of different styles of folding above and below of this formation. So that the structures in the upper and lower parts of this formation are completely separated and do not match each other. In the upper anticlines, above the Gachsaran horizon, the calculation of the limbs angle, the main thrust slope and the percentage of forelimb thickening indicate the fault detachment fold style. This style marks the geometry of fold at the early stage of the development of this anticline. Also the seismic profiles below the Gachsaran horizon also show the fault-propagation folding style. In the south Dezful Embayment, folding in the Gachsaran Formation occurs with shorter wavelengths in the form of disharmonic folds. This folding acts as the decoupling surface for the lower folds so that the synclines in this moving horizon directly cover the lower anticlines. The rounded folds in the carbonates in lower anticline are the imposed folds associated with steepened up reverse faults, detached on the basal decollement level and ultimately faulted by progressive deformation. The interpretation of seismic sections in the southern Dezful Embayment shows that lateral migration occurs in the salt units of the GS2 and GS4, and the upper and lower units of the Gachsaran Formation do not play a role in salt migration. Lateral migration in Miocene salts of the Gachsaran Formation is accomplished by the growth of sub-anticline during folding and loading of upper formation at the upper Gachsaran Formation. Manuscript profile
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  4 - Difference of in situ stress regime dependent on Structural position and geomechanical characteristics, Case study- Gachsaran and Asmari formations, SW Iran
  Hossein Talebi Seyd Ahmad Alavi Mohamad Reaz Ghasemi Shahram Sherkati
  Estimation of in-situ stress tensor in sedimentary basins using information obtained from exploration and development oil and gas wells during the drilling and logging process may be used for estimation of in-situ stress tensor in sedimentary basins. The in-situ stress More

  Estimation of in-situ stress tensor in sedimentary basins using information obtained from exploration and development oil and gas wells during the drilling and logging process may be used for estimation of in-situ stress tensor in sedimentary basins. The in-situ stress magnitude and orientation and the resulting stress regime around the studied wells have been several application in secondary recovery programs from hydrocarbon reservoirs as well as wellbore stability analysis. In this paper, the magnitude of in-situ stress is estimated by using abovementioned data in some oil wells located in the south west of Iran. Increasing the oil production by hydraulic fracturing design and sand control in the multi-layer reservoirs such as the Marun giant oil field with loose sand horizons and also improving drilling performance in the Gachsaran formation¬ requires knowledge about the prevailing stress conditions. This research, tries to analyze the stress regime of the Asmari and Gachsaran Formations around the selected wells in the Marun and Lali fields using constructed Mechanical Earth Models (MEM) and their differences are discussed. The calculated stress magnitudes in studied wells indicate a significant drop in magnitude of horizontal stresses from the Gachsaran to Asmari reservoirs in the Marun oil field. The magnitudes of the three principal stresses resulted that SHmax is the maximum principal stress and the Shmin is the minimum principal stress, thus a strike-slip stress regime (SHmax>Sv>Shmin) dominates in the Gachsaran sequence and the Asmari formation of the Lali oil field. however, in the Gachsaran formation of Marun giant oil field, stress regime is reverse-strike slip but normal stress regime is dominated in it's Asmari reservoir. The In-situ stress condition indicates that the structural condition and the depth difference of these structures plays an important role in the tectonic stress regime changes. Manuscript profile
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  5 - Employing different techniques to explore, modeling and reserve estimation of gypsum deposit in the northwest of Tafresh district, Markazi province
  Reza Ahmadi
  <p>In the present research, to explore gypsum reserves in the northwest of Tafresh district, a complete process including prospecting to reserve estimation has been carried out. To achieve the goal, first, an extensive area of 4500 km2 was investigated using remote sens More

  <p>In the present research, to explore gypsum reserves in the northwest of Tafresh district, a complete process including prospecting to reserve estimation has been carried out. To achieve the goal, first, an extensive area of 4500 km2 was investigated using remote sensing operation through Landsat 8 Operational Land Imager (OLI) images. Using proper pre-processing and processing techniques containing principal component analysis, false color band combination, least squares regression and spectral angle mapper on the images, 17 promising areas scattered in the region were identified. Based on more detailed studies and field surveys of the promising areas, it was specially focused on Darbar gypsum deposit located nearby Darbar village. Therefore, a variety of exploratory activities comprising six trenches with a total volume of 135.61 m3, one stope (selective mining unit), 1:1000 topographic-geological map, chemical analysis of 9 samples and drilling of one exploratory borehole with a depth of about 40 m was performed. The results of the chemical analysis of the samples show that the total percentage of SO3 and CaO compounds for all tested samples is more than 76%. In addition, the result of the technological test to determine the quality characteristics of the stone and baking ability in the pilot scale evaluated by Nizar Cement Factory of Qom is desirable. Gypsum modeling and reserve estimation of this deposit were also done with the classical method of contour lines using Surfer software. Based on the calculations, the in-place reserve of Darbar gypsum deposit was estimated significant amount of 5982610 tons.</p> Manuscript profile