The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, , 26-28 April 2010

Study on geomorphology dynamics of limestone-shale collapse in the Kollah-Ghazy Area, south Esfahan, Iran

A.Vali,R.Ghazavi,R.Ghasemi, A.behpouri

Faculty members in agriculture and Natural Resources College of . University.

Corresponding author: [email protected]

Abstract The focus of geomorphology is concerned with an analysis of the nature, arrangement and differentiation of landforms and an understanding of the processes that have shaped or are shaping those landforms. Uplift at the end of Cretaceous and beginning of the Tertiary created asymmetric domes. Foresets of limestone and shale in stratigraphic units of Shear folding area to Cretaceous in the Kollah-Ghazy of south and south-east of Esfahan have resulted in many collapse features that have developed several shapes like cuesta. Erosion of these uplifted rocks produced the present landscape .resistant sandstone that are ordered near the shale layer has been formed the cuesta like form .Results of morphology showed in spite of these forms lay in folded structure, they have any characteristics that they have contained in monoclimb structures such as foresets of hard and weak layers with temperate slope in construction simple and agreeable limb. In this paper we have tried to investigate the relationship between slope particulars and speed of destruction and layer dynamics, with measuring some geomorphology quantitative parameters. Analysis of regression showed a significant relationship between slope of weak layers with slope and thickness of hard layers. Also the slope of weak layer desire to angle of repose because of weathering effects, gravity and friction forces. So if the slope of weak layers exceed from the slope of repose, the hard layer destroy slowly and vice versa. According the results the among of the weak slope is suitable generally for velocity of destroy forests and study its dynamics. Conclusion of limestone and shale and formation of the forms like cuesta in this area has led to different problem in environmental management because of the cuesta limb ready for rock falling .Appreciation of the landscape of these geomorphologic features involved in the activity of human for quarry of stone that should be considered in land use planning in the south and south-east of Esfahan city where urban population need to the natural landscape for refreshment.

Key words: Geomorphology,cuesta like from, , angle of repose, forests, Kollah –Ghazy.Esfahan.

1.Introduction The science of geomorphology has certain common elements, regardless of the scale of investigation or the system being examined. A fundamental proposition of geomorphology was proposed in which landscape stability was described as a function of the temporal and spatial distributions of the resisting and disturbing forces. Land future is frequently the driving force in many systems and human activity acts as a modifying influence understanding and predicting change is not, however ,merely a matter of understanding the mechanics of the change process. It requires the recognition and comprehension of the nature of the links between individual system components concepts such as thresholds of change (Schumm, 1977), response time and magnitude, rates and paths of change and recovery, are all important if the full nature of changes are to be appreciated

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

(Brunsden, 1990).There is little doubt that the resistance of natural systems to change, be they geomorphological ,is complex and poorly understood subject.Stratigraphic units and its sensitivites is considered by most of moderns geomorphologists to be one of several independent variables that effect the morphology and evolution of landscapes (Kinghton; 1984, Ritter;1986,Schumm;1977,Schumm and Lithy;1965). Whereas advances have been made in understanding many of the processes leading to changes in landscapes, recent scientific advances have shown the joint nature of forms and processes driving many geomorphic system changes and the nature of feedback processes between physical and morphological systems (e.g., Zeng et al., 1999). Detail on the coupling effects between these two systems, however, is poorly understood (e.g., Scheffer et al., 2001). Thus, with increasing pressures on the environment, a strong trend exists to manage environmental changes (Thoms and Parsons, 2002).Terzaghi(1969),Robertson(1970),Einstein et al(1995), Eberhardt et al(2001)and several researchers developed some physical and mechanical approach for stability of slope with complexity equation. Morphological study of slope dynamic is less than physical study. At present geomorphologists decide to solve this problem by investigation morphometric relations. One of the active and sensitive slopehills is cuesta and pseudo cuesta like forms. changing in ancient sedimentation environmental was caused to establish its landscape. Foreset of limestone and shale in stratigraphic units of shear folding area and uplift process at the temporal period was affected to appear pseudo cuesta like forms. Erosion of these uplifted rocks produced the present landscape. The difference between soft and hard layers resistance has been formed geomorphic form that they are susceptible of change. The objective of this paper is to quantity several morphological of hillslope of topographic development to find a single relationship that can be used to characterize sensitivity of landscape.

2. Regional setting of study area The study area is in the Kolah Ghazy national park in southern Isfahan city in Iran (fig.1). The area is about 40 km².major rock groups are the Albian with genus of calcareous grey shale containing ammonites and small gastropods,Turorian-coniacian kind of bedded limestone containing Inoceramus and Globotruncana.

3. Methods Morphological parameters were studied by analyzing and relating of downhill slope containing among of slope, thickness of soft and hard layers and the direction and the shape of forehead of hard bedrock layer. Analysis of regression was applied for investigation the relationship between slope particulars and speed of destruction and layer dynamics, with measuring some geomorphology quantitative parameters.

4. Results The physiographic and geologic structure of the Kollah Ghazy has found two wrinkled mountainous string from lower and middle part of Cretaceous sediment. The study area (pseudo cuesta like form) has been fixed during several minor fault and uplift process has

1974

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 been done present of limestone-shale collapse from upper Cretaceus.results of analysis of regression for hillslope parameters has been showed in tab.1. Results showed a significant relationship between two scopes with the coefficient of determination(R²)of 0.763.Also soft hillslope with thickness of hard layer has a significant relationship with 0.532 for R².The highest coefficient of determination belong to multivariate regression between soft hillslope and two parameters of hard hillslope (slope and thickness)with R² of 0.838. Comparison of among of slope for two scopes (tab.2) illustrates a significant difference (α‹0.001) between means (tab.2). Measurement angle of repose for shale of soft slope with field examination obtained equal 25.47 percent.

5. Conclusions A series of limestone-shale collapse are located in study area and the base of the formation is two beds of soft and hard layers that they have been formed a cuesta like form in a folding system and appearance these features along several fault because of uplift process. On these geomorphic form two type of hillside, a simple bedrock slope and a compound slope of alternate soft and hard layers. with due attention to obtained the relation ship between slope of compound hillslope(soft layer) and simple bedrock hillslope(slope and thickness)can be state increasing in the bedrock slope and thickness was cased increasing the slope of soft hillslope.if slope of compound hillside were as big as the angle of repose ,destruction speed in bedrock would be fixed. Therefore comparison slope of soft layer and angle of repose itself can be state for bedrock destruction. So if the slope of weak layers exceed from the slope of repose, the hard layer destroy slowly and vice versa. According the results the among of the weak slope is suitable generally for velocity of destroy forests and study its dynamics. Conclusion of limestone and shale and formation of the forms like cuesta in this area has led to different problem in environmental management because of the cuesta limb ready for rock falling .Appreciation of the landscape of these geomorphologic features involved in the activity of human for quarry of stone that should be considered in land use planning in the south and south-east of Esfahan city where urban population need to the natural landscape for refreshment.

References [1] Bjerrum L.1967. Progressive failure in slopes of overconsolidated plastic clay and clay shales. J Soil Mech Foundat Div ASCE;93(SM5):1–49. [2] Eberhardt E, Willenberg H, Loew S, Maurer H.2001. Active rockslides in Switzerland— understanding mechanisms and processes. In:International Conference on Landslides—Causes, Impacts and Countermeasures, Davos,. p. 25–34. [3] Einstein HH, Lee JS.1995 Topological slope stability analysis using a stochastic fracture geometry model. In: Proceedings of the Conference on Fractured and Jointed Rock Masses, Lake Tahoe,. p. 89–98. [4]Knighton, D.1984.Fluvial forms and processes: Victoria, Austoralia.Edward Arnold,Ltd.,217p. [5]Ritter,D.F.,1986.Process Geomorphology,2th.Dubuque,Wm,C.Brown publishers.579p.

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

[6] Robertson A.M. 1970 The interpretation of geological factors for use in slope theory. In: Planning Open Pit Mines, Proceedings, Johannesburg,. p. 55–71 [7]Scheffer, M., Carpenter, S., Foley, J.A., Folke, C., Walker, B., 2001.Catastrophic shifts in ecosystems. Nature 413, 591–596. [8]Schumm,S.A.1977.Geomrphic thresholds:the concept and its applications.Transactions of the insititue of British GeogrPHERS:485-515. [9] Terzaghi K. Stability of steep slopes on hard unweathered rock. G!eotechnique 1962;12:251–70. [10]Thoms, M.C., Parsons, M.E., 2002. Ecogeomorphology: an interdisciplinary approach to river science. International Association of Hydrological Sciences 227, 113–119. [11]Zeng, N., Neelin, J.D., Lau, K.M., Tucker, C.J., 1999. Enhancement of inter decadal climate variability in the Sahel by vegetation interaction. Science 286, 1537–1540. Tab.1.The validation statistics of different relationship for data set. No Relationship(variable) R R² F P value 1 Soft slope &Hard slope 0.873 0.763 28.917 0.000 2 Soft slope & Hard thickness 0.729 0.532 15.902 0.001 3 Soft slope & (Hard thickness and slope) 0.915 0.838 20.630 0.001 4 Soft slope & Soft thickness 0.090 0.008 0.116 0.739 5 Hard slope &Soft thickness 0.460 0.211 2.140 0.155 6 Hard slope &Hard thickness 0.419 0.175 1.915 0.200 7 Hard thickness &Soft thickness 0.381 0.145 2.380 0.145

Tab.2.mean comparison of soft slope with soft slope without bedrock (angle of repose). Mean Std.Deviation N t Sig. Soft slope in collapse 29.6 1.18 Soft slope without 25.47 0.92 14 12.848 0.001 bedrock(angle of repose)

Fig.1.Typical exposure of limestone-shale landscape in Kollah Ghazy, southern Isfahan , Iran

1976

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 Evaluation of Petrophysical Properties of an Oil Field and their effects on production after gas injection

Abdolla Esmaeili,

National Iranian South Oil Company (NISOC), Iran E- mail: [email protected]

Abstract This paper presents results of a study conducted to determine and evaluate Petrophysical properties of an Oil Field and their effects on production from this field while under gas injection. To estimate most of petrophysical properties of this oil field, we used well logs. After determining and evaluating petrophysical properties of this field, we describe how these properties affect reservoir quality and EOR strategy.

Introduction Petrophysical of any oil field include reservoir fluid properties and reservoir rock properties. In other words these properties are divided into static petrophysical properties and dynamic petrophysical properties. Dynamic petrophysical properties are related to reservoir fluid and static petrophysical properties are related to reservoir rock. Petrophysical properties of oil reservoirs affect their ultimate recovery and amount of oil production. These properties include porosity, permeability, viscosity, wetability, fluid saturation, mobility, fracture distribution, drive mechanism, etc. Reservoir engineering calculations are based on the petrophysical properties of reservoir rocks that contain fluids. First, general lithologic type of reservoir rock and their different petrophysical properties are obtained out. Then we must deal with rock porosity and fluid saturations, which important to reservoir engineering because they are the principal factor involved in determining the amount of oil and gas originally in place. These are various methods of measuring porosity. Then we must deal with permeability, a measure of the ease with which fluid flows through the pore spaces of rock. Absolute, effective and elative permeability are described and their importance and interrelationships pointed out. Production from any of the oil fields is accompanied by a pressure decline. The rate of propagation of the pressure decline is such that the pressure may be significantly reduced many miles away from a producing well. Therefore to prevent pressure drop due to oil production from a reservoir we must inject gas in the reservoir to be able to at least establish the reservoir pressure. Petrophysical properties of a reservoir affect recovery factors and recovery methods. In this paper, we have studied petrophysical properties of an oil field to determine how these properties affect oil production and ultimate recovery.

Rock Properties and their Effects on Reservoir Quality The average matrix permeability and therefore the pore type distribution in a reservoir is most important factor in reservoir characterization and EOR planning. The petrophysical properties such as porosity, permeability, saturation and capillary are related to engineering parameter of permeability and saturation. Most of the oil in the fracture is naturally depleted in the first

1977

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 phase of production. Capillary – trapped oil in the dense area of the reservoir is the main target for EOR phases. Three main classes of rock fabric are found in this reservoir. Class1 rock fabric mainly consists of limestone, dolomitized grainstone and grain dominated dolopackstones. Class2 rock fabric consists of grain dominated packestones, grain dominated dolopackestones and mud dominated dolostones. Class 3 rock fabric consist of mud dominated wakestone and mudstone. Various type of connected pore such as interparticle, inter crystalline, touching vugs and fracture were found in this reservoir, while moldic and separated vugs are the main type of the non-connected pore. Main pocket of the oil were found in the dense non-fractured sector of this reservoir. The layer with well-connected network of micro-intercrystalline inters granular nad vuggy porosity are the best target in the development phases of this reservoir. The reservoir characterization is the bases of reservoir development. The reservoir properties are mainly consisting of static properties like texture, rock fabric, porosity, permeability etc. and dynamic properties like fluid properties, pressure, temperature etc. Geologists divide the rock type according to their mineralogical composition, grain size and texture while petrophysist classified the rocks on the basis of their petrophysical properties mainly porosities and permeabilities. These parameters make the basis of reservoir characterization. The relation of petrophysical parameters such as porosity, permeability and saturation is the key factor in reservoir characterization. Logs, core analyses and production data, pressure buildup data provide quantitative measurements of petrophysical parameters in the vicinity of the well bore. Studies that relate rock fabric to pore-size distribution, and thus to petrophysical properties are key to quantifying geologic models in numerical terms for input into computer simulation. In this study on basis of porosity derived from log analysis, porosity and permeability derived from routine core analysis and visual porosity from petrography study, the reservoir were divided into 3 different rock fabric classes. Log data from several wells were analyzed and correlated with core data and petrography data from the same well. Several types of porosity were identified in this reservoir. The main type of porosity are mainly inter granular, inter particle touching vugs and fractures, forming inter connected pore system. Non touching vugs, moldic, chanel and fenestral are other types of porosity. Intergranular porosity is mainly found in grainstone and thinly bedded sandstone with high permeability and good porosity permeability relationship. Vuggy porosity is mainly found in dolostone and some wackestone while moldic porosity are mainly in wackestone packestone rock type. Rock fabric classification based on the petrophysical parameters for this reservoir indicates that: I) Zone one of this reservoir is petrophysically classified as class 3 and 2 rock fabric within the permeability fields of less than 100 micrometers. II) Zone 2 is mainly in class 2 rock fabric with grain dominated pack stone within the permeability field of 20 to 100 micrometers and class one rock fabric within the permeability field of more than 100 micrometers. III) Zone three is mainly classified as class 3 rock fabric within the permeability field of less than 20 micrometers and considers as a pore reservoir. IV) Limestone indicates wide range of porosity permeability relationship as compare to dolostone due to wide range of pore type distribution. VI) Connected pore types in this reservoir are mainly inter granular inter particle, touching vugs and fractures, forming inter connected pore system.

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

Fluid Injection Problems of this Reservoir We studied key physical mechanisms and calculation methods for fluid flow in this fractured reservoir. The main matrix – fracture fluid exchange mechanisms described are gravity drainage, capillary imbibition and molecular diffusion. Important issues such as capillary continuity between matrix blocks, reinfiltration of fluids from higher to lower blocks and effect of block shape on flow processes are also addressed simulation studies of water flooding in fractured reservoirs are reported for the purpose of identifying the effects of gravity and capillary forces on oil recovery. Included are studies of effects of capillary continuity and degree of wetting. The results show that for intermediately wetted systems, capillary continuity has a major effect on oil recovery. Laboratory processes involving high pressure gas injection in fractured systems have been studied by compositional simulation. The results show that changes in interfacial tension caused by diffusion may have effects on oil recovery. The only solution to more representative modeling of flow in fractured reservoirs is more detailed calculations. A multiple grid concept is proposed which may drastically increase the detail of the simulation. Numerical modeling of naturally fractured reservoirs using dual porosity models has been the subject of numerous investigations. In the dual-porosity and dual-porosity / dual-permeability formulations most commonly used to model fractured reservoirs, proper representation of imbibition and gravity drainage is difficult. In some formulations, attempts have been made to represent correct behavior by employing a gravity term and assuming a simplified fluid distribution in the matrix. Despite the efficiency of water flooding in fractured reservoirs, considerable oil will be left behind due to relatively high residual saturations. This residual oil may be a target for high pressure gas injection. The recovery mechanisms involved in high pressure gas injections in fractured reservoirs are complex and not fully understood. They include viscous displacement, gas gravity drainage, diffusion, swelling and vaporization/stripping of the oil. Inter facial tension gradients caused by diffusion may also play an important role on the overall recovery. Viscous displacement normally plays a minor role, except perhaps in the near vicinity of the wells where the pressure gradients are large. Contrary to conventional reservoirs, diffusion may play an important role in fractured reservoirs. The injection gas has a tendency to flow in the fractured system, resulting in relatively large composition gradients between fracture gas and matrix hydrocarbon fluids. Thus there is a potential for transport by molecular diffusion. This is especially the case in reservoirs with a high degree of fracturing (small matrix block sizes). Diffusion is difficult to model. A problem arises when gas is injected in an under saturated reservoir. The minimum contact saturation between the fracture and matrix grid block will be zero, and no diffusion between the two media will be calculated. With matrix block heights lower than the capillary entry height, no mass transfer between fracture and matrix system will be occur. Physically, the mechanism for gas entering from the fracture to an under saturated oil would require an ultra-thin contact zone at the fracture / matrix interface. In this zone a small amount of equilibrium gas will exist, and diffusion transfer between fracture and matrix can occur via this zone, as gas-gas diffusion between fracture gas and equilibrium gas in the two phase zone, and as liquid-liquid diffusion between under saturated matrix oil and saturated oil in contact zone.

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

A problem arises when gas is injected in an under saturated reservoir. The minimum contact saturation between the fracture and matrix grid block will be zero, and no diffusion between the two media will be calculated. With matrix block heights lower than the capillary entry height, no mass transfer between fracture and matrix system will be occur. Physically, the mechanism for gas entering from the fracture to an under saturated oil would require an ultra- thin contact zone at the fracture / matrix interface. In this zone a small amount of equilibrium gas will exist and diffusion transfer between fracture and matrix can occur via this zone, as gas-gas diffusion between fracture gas and equilibrium gas in the two phase zone, and as liquid-liquid diffusion between under saturated matrix oil and saturated oil in contact zone. The simulated results indicate that the recovery can roughly be divided into three production stages: 1- primary swelling of the oil 2- secondary swelling and vaporization 3- final vaporization of the oil. The initial stage is dominated by swelling of the oil inside the core, due to liquid-liquid diffusion between the under saturated oil inside the core and the saturated oil at the outer surface of the core. The light components of oil (mostly methane) diffuse into the core, while the intermediate oil components from the core diffuse to the outer contact zone. During this stage there is some viscous flow from the center of the core to the fracture, due to swelling of the oil and interfacial tension gradients. The oil produced to the fracture is vaporized by the injection gas and no free oil is observed. The first stage ended when some of the oil within the core first became saturated. This marks the beginning of the second stage m where free gas saturation advances toward the center of the core. As the gas front advances, the gas – gas diffusion will play a more dominant role on the recovery process. During this stage, mainly light-intermediate, and the intermediate components of the oil are vaporized. When the light-intermediate and most of the intermediate components have been recovered, the third stage begins. During the last stage, mostly heavy- intermediate and heavy components are vaporized. This stage is slow compared to the first two stages, but a large additional recovery may be achieved. So we can say that high pressure gas injection may yield high oil recoveries due to reduction in interfacial tension caused by diffusion.

Field Characterization Fractures This reservoir has some fair fractures which make connection between the pore volume across and along the reservoir. Generally the most fracture extends in reservoir crest. The good connection at the west shows the fracture consequently where as shale layers in half part of reservoir reduce vertical permeability. Production Mechanisms The production mechanisms of this reservoir are as follows: 1- Gravity segregation in fractures 2- Capillary– gravity displacement between matrix and rock cracks in water wet reservoir. 3- Weak water drive near WOC 4- Gas drive 5- Dissolved gas Average Reservoir Permeability To determine the average permeability (fracture and matrix permeability), the build up pressure well test was done and ported to eclipse well test software. The following results achieved: 1- Average permeability = 5.62 2- Skin factor = 3.05 Thus the fracture makes the good system grid but there is negative skin effect. Vertical vs Horizontal Permeability

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

Since the permeability measurements in the laboratory have been made on core plugs of small size, normally it is not expected that the vertical permeability to be different from horizontal permeability except that the formation is highly laminated. Presence of shale and anhydrite streaks, stylolites and valcilite filled fractures all restrict vertical flow and on the layer sizes common in the simulation models, they will cause a reduction in vertical permeability. A fraction of 0.1 is quite common to be applied to horizontal permeability and use it for vertical permeability. Grain Density Grain density has been measured on core samples of wells. The mean and median grain densities are calculated to be 2.809 and 2.800 respectively, which are almost the same due to the symmetry of the distribution. Small frequency of low grain density values is an indication of rare presence of sandstone in the main carbonate reservoir. Average Reservoir Porosity Using 15 well logs, average reservoir rock porosity was estimated to be 8.9%. Water Saturation Water saturation is a function of porosity and for this reservoir is estimated: Sw = 28 %. Buble Point

Buble point of this reservoir is constant in a 11oil well PVT data in at 150º C: Pb = 2956. Fluid Level Contacts Gas oil contacts in north, south and west of this field is calculated by means of average oil and gas pressure and are 1601, 1601, 1601 sub sea meter respectively. Oil water contacts are 1896, 1886 and 1885 for north, south and west side of reservoir respectively. Fluid Pressure Oil pressures according to static pressures are 2481, 2474 and 2456 psi for north, south and west side of reservoir respectively in reference depth of 1800 meter sub-sea. Gas pressure is measured in 1100 meter sub-sea and are 2166, 2161and 2137 psi for north, south and west side of reservoir respectively. Water pressures are measured in 2150 meter sub-sea by static pressure test and are 2930, 2950 and 2950 for north, south and west of this reservoir respectively. Production Gas Oil Ratio (GOR) In accordance to the tests which is conducted in this reservoir, the initial gas oil ratio (GOR) of this reservoir was measured to be 700 cubic feet per barrel. Because the reservoir is a saturated reservoir and pressure drop due to oil production from this reservoir the gas oil ratio decreases and now this is 600 cubic feet per barrel. Initial gas oil ratio (GOR) which was measured by PVT tests was 860 cubic feet per barrel of oil. Rock Type According to the cores from wells we studied this reservoir rock and depends on porosity, permeability and water saturation, we divided this reservoir into five section by means of petrophysical logs.

Gas Injection in this Field We inject 400 MMscf/D gas this oilfield to prevent its pressure depletion and to increase pressure of the reservoir. Gas injection in this field is performed by a gas compressor station. The variation of fluid composition with depth in a reservoir is called compositional grading.

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

As depth increases, the mole fraction of light components decreases, density increases and GOR decreases and accurate characterization of reservoir fluids becomes more critical. In this oilfield, we inject gas to gas cap of the reservoir. This fractured carbonate reservoir is produced under natural depletion mechanisms at the all of its life time. In this reservoir, oil properties vary with depth. The bubble point pressure decreases with depth along with values of oil volume factor and solution GOR (gas–oil ratio). Oil gravity and viscosity increases with depth. Gas injection in this field is done through 6 injection wells. We inject gas to reservoir by these six wells and produce by oil production wells. To have a good injection in naturally fractured reservoir, we must have: a) good design of facilities for gas injection b) good reservoir properties for gas injection.

Field Production Problems This reservoir is a non homogeneous reservoir and has two gas caps. Its reservoir rock mainly contain of calcite carbonate and dolomite rocks with layers of shale and salt in different parts of reservoir. Depending on the petrophysical data, this reservoir divided into four sections which is separated by shale layers with low porosity from each other. Distribution of shale layers in the reservoir is such that there is a connection between zones vertically. In its production view, this reservoir has divided into three section which are south, north, and south sections of this reservoir is very good but in the west section we have a bad production because of existing a salt and calhore layer and ack of a good fracture system. Oil loss per each barrel of produced oil is .25 and its pressure drop is .87 psi per million barrel of produced oil .because this is a fractured reservoir, an amount of the gas which is injected into the reservoir goes into the empty fractures of oil and goes into the production column of oil wells and come back to the surface with produced oil and cause some producing problems in oil production units and oil pipelines which transports oil from wells to production units. Two main production mechanisms in this field are solution gas and gas cap gas expansion Because the reservoir rock in west section is a dense rock, well completion in this section must be open hole. There are some wells in this section which were completed as a cased hole well and this is a cause for insufficient production from this section. Because of a very large numbers of vertical and horizontal fractures in reservoir rock, drilling operations in this formation is generally with high loss and because lack of control facilities to control this loss, well drilling is stopped and we can not reach to predicted depth and can not receive to final purpose of horizontal wells for optimization and longer production from this reservoir.

Conclusions 1- Reservoir of this field is a fractured carbonate reservoir with un uniformly distributed fractures throughout the reservoir 2- The numbers of fractures in crest of reservoir is more than other parts 3- This reservoir is a saturated reservoir and has a gas cap throughout the reservoir. 4- In accordance to PVT tests and oil properties, oil composition throughout the reservoir is the same 5- Oil production from north and south sections are better than west section. 6- To now about 59 % of initial oil reserve of this reservoir has been produced. 7- Oil loss is 25% for each barrel of produced oil. 8- Reservoir pressure drop is 0.87 psi for each one million barrel of produced oil. 9- In most cases production of this reservoir is by means of gravity drainage. 10- Delay in starting gas injection causes a more oil loss and pressure drop.

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

11- Gas injection in this field must be continued to increase pressure and to prevent pressure drop. 12- Any drilling in this field must be done by under balance drilling technique. 13- Decreasing oil production from this field to let it for compensating energy loss to prevent more oil loss. 14- The reservoir rock permeability is low and to increase oil production we must increase gas injection to maximum capacity and to let the oil in matrix enough time to go to oil column other wise, by increasing oil producing rate, oil column will be decreased and because of a large amount of fractures in this reservoir oil producing wells will connect to gas cap gas injection causes oil column to go down and increasing gas production from oil wells.

Acknowledgement The author wishes to express his sincere thanks and gratitude to technical manager of Aghajari Oil and Gas Production Company (Aj.O.G.P.C). I also wish to thank the Heads of Research and Technology Department in National Iranian South Oil Company (N.I.S.O.C) and Heads of Research and Technology Department in National Iranian Oil Company (N.I.O.C) for their helps and encouragements in connection with this study. I am grateful for all their assistance.

References 1- D.R Mc Cord & Assoc. , " Reservoir Engineering and Geological Study Analysis for Fracture Operation" , vol. 2 , 1974. 2- " Log Interpretation Charts " , Schlumberger Well Services , 1989 . 3- "Schlumberger Log Interpretation Principles", Schlumberger Educational Services, 1989. 4- Sylvain j. pirson, "WELL LOG ANALYSIS", Prentice-Hall, 1989. 5- Thompson & Wright, "OIL PROPERTY EVALUATION", Colorado School of Mines, 1985. 6- Calhoun, J. "Fundamental of Reservoir Engineering", university of Oklahoma press,1973.

1983

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

Silicification of Carbonate Rocks of Chehel-Kaman Formation (Upper Paleocene) in the West of Kopet-Dagh Basin, NE Iran

Akbar Heidari, Asadollah Mahboubi and Reza Moussavi-Harami

Department of Geology, Faculty of Science, Ferdowsi University of Mashhad E-mail address: heydari.1982@ yahoo com

Abstract Several diagenetic processes, which one prominent process is silicification, affected the Upper Paleocene carbonate rocks of Chehel-Kaman Formation in the Western Part of Kopet-Dagh basin (NE Iran and S Turkmenistan). The aim of this study is classification and interpretation of digenetic processes and environments for mentioned different silicification types. Five types of silicification are recognized in this study that formed in three diagenetic phases. Based on appearance and the place of silicification, two models (Immediate and late) for silicification interpreted. Silicification happened as three forms including micro and macro quartz as well chalcedonies. Micro types formed as solution voids filler and, do not follow any regular pattern. Macro types precipitated as four different forms, first type filled vacant voids between allochems in ooid grainstone facies that we have interpreted as oolithic shoals. This type is not fabric selective but can be commented facies selective. Second macrotype, formed in fractures and intersect the texture of the carbonate rocks. It is formed in a wide rang of facies. Third type of macrotype has seen as macroquartz that occurred in deepest facie. The Last feature of silicification is chalcedoic type that formed as fabric selective. This type precipitated in brachiopods and some bivalve shells with foliated fabric. Silicification of the carbonate rocks must have been taken place under acidic conditions (pH<7). In this conditions quartz precipitated and carbonate dissolved and provide appropriate space for next phase of silicification. Based on these diagenetic processes, formation of quartz and chalcedony infer as mixed (Eogenes phase that precipitated some of microquartz type), burial (mesogenes that deposited some micro-macro quartz and chalcedonic types) and uplifting zones (telogenes phase that some macroquartz type spatially fracture type formed in it).

Key Words: Silicification, Carbonate Rocks, Chehel-Kaman Formation, Diagenetic.

Introduction The Kopet-Dagh Intracontinental Basin situated in northeastern Iran and southern Turkmenistan. This Basin Formed after (Berberian and King, 1981; Ruttner, 1993). Relatively continuous sediment deposition took place from the Jurassic through the Neogene time in Kopet-Dagh basin (Afshar-Harb, 1994). The thickness of these sediments in the Iranian portion reached up to 8 km (Afshar-Harb, 1994), while in Turkmenistan it may have reached up to 15 km (Lyberis and Manby, 1998). The early Paleocene regression followed by the transgressive of the sea and deposition of marine sediment of the Chehel-Kaman Formation that overlies Pestehleigh Formation. The basin folded during the Late Alpine compressional events and created many anticline traps such as those that contain the Khangiran and Gonbadli gas field, in northeast Iran (Moussavi-Harami and Brenner, 1993). One of the diagenetic processes that affect carbonate rocks of Chehel-Kaman Formation is silicification. The objective of this study is detail consideration of the processes including various stages of Formation and diagenetic environment. Two stratigraphic sections including Garmab and Jowzak in the west Kopet-Dagh basin measured and sampled (Fig. 1) and 50 stained thin sections have studied.

Discussion

1984

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

Silicification is a diagenetic process that can be helpful and sort some problems out such as amount and concentration of silica in diagenetic fluids and time of silicification than other diagenetic processes (Hess, 1990). Silicification and its replace in carbonate rocks needs high concentration of silica (Maliva and Siever, 1988). Silicification is a plenty process but replacing mechanisms are not completely understood (Daley and Boyd, 1996). Silicification of carbonate rocks of Chehel-Kaman Formation performed in five different types in study area. Three features have seen in one facies (Bioclastic Floatstone). The first type (major type of silicification) carried out in deepest facies of studied interval that is known as Bioclastic Floatstone facies (D4) (Heidari, 2007) (Fig. 2A, B). It is fabric selective and affected partial brachiopod shells and appeared as chalcedonic forms (big spheroids), but other allochems such as bivalve clasts are not silicified and they recrystalized by blocky calcite. Foliated microstructure is main fabric of brachiopod shells and this microstructure can be effective and increase permeability and transfer of diagenetic liquid (Daley and Boyd, 1996). As a result, foliated fabric can be responsible for this kind of silicification. Second type of silicification also occurred in Bioclastic Floatstone (D4), but it formed in a different feature as microquartz type in the matrix of facies (Fig. 2C). The size of silica crystals range from 1-2 µm and categorized as microquartz type. It filled voids and some parts of primary void are vacant yet that is a good evidence for prove a dissolution phase prior type 2 of silicification.mThird type is resemble to previous type and formed in vacant voids in D4 facies, but the size of them is range from 2-3 mm and categorized as macroquartz type. Forth type of silicification is facies selective and occurred just in dissolution voids between ooids in Grainstone facies (Fig. 2D). Finally last type occurred in fractures (Fig. 2E), and in some cases crossed type one that could indicates precipitation of this type after it (Fig. 2F). Dissolution of calcite and consequently silicification occurs in two different stages including immediate and late (Schmit and Boyd, 1981). In Immediate stage there are some remains of silicified allochems and there is no any trace of dissolution (pattern 5 from Schmit and Boyd, 1981), but in late silicification, there are some voids those formed in previous phase and silica fill some of them (pattern 1 to 3 from Schmit and Boyd, 1981). Based on petrographic studies in this case study, there are immediate and late stages of silicification in Chehel-Kaman‘s carbonate rocks: A) Marine Model supposed for type 1 (Immediate): this model appears as chalcedonies and replaced in brachiopod shells. Some evidences of immediate silicification in this type are selective silicification, remain parts of silicified shells and there is no any dissolution in silicified brachiopod shells that reinforced the immediate theory for type 1. B) Mixed Zone (marine and meteoric) to shallow buries for types 2, 3, 4 and 5 (Late): these four types often have grown in vacant voids. Therefore, silicification carried out after an extensive dissolution that supplied appropriate space for next process (silicification). C) Final (After uplifting) for type 5. This type of silicification crossed other types and developed in fractures, which could indicate it carried out after uplifting.

Conclusion Silicification is a prominent digenetic process that appeared in five different types in Chehel- Kaman carbonate rocks. Petrographic studies lead to interpretation of three diagenetic stages including immediate (marine), late (burial), and final (after uplifting).

References 1. Afshar-Harb, A., 1994, Geology of Kopet-Dagh, The Project of Compiling of Geology of Iran‘s Books, Ministry of Industries and Mine Geological Survey of Iran, 275pp. 2. Berberian, M., and King, G.C.P., 1981, Toward a paleogeography and tectonic evolution of Iran, Canadian Journal Earth Sciences, v. 18, p. 210- 265.

1985

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

3. Daley, R.L., and Boyd, D.W., 1996, The role of skeletal microstructure during selective silicification of brachiopods, Journal of Sedimentary Research, v. 66, no. 1, p. 155-162. 4. Hesse, R., 1990, Silica diagenesis, origin of inorganic and replacement cherts. In, Mcllreath, A., Morrow, D.W. (Editors), Diagenesis. Geoscience Canada, Reprint Series, 4, Canada, p. 253– 275. 5. Heidari, A., 2007, Interpretation of Sedimentation History and Sequence Stratigraphy of Pestehleigh and Chehel-Kaman Formations in the West of Kopet-Dagh Basin, NE Iran, Ferdosi University of Mashhad, Iran, M.Sc Thesis, 375 pp. 6. Maliva, R. and Siever, R., 1988. Pre-Cenozoic nodular cherts, evidence for opal-CT precursors and direct quartz replacement. Am. J. Sci, v. 288, p. 799-809. 7. Lyberis, N. and Manby, G., 1998, Post-Triassicv evolution of the southern margin of the Turan plate, C. R. Acad. Sc., v. 326, p. 137-143. 8. Moussavi-Harami, R. and Brenner, R.L., 1992, Geohistory analysis and petroleum reservoir characteristics of Lower Cretaceous (Neocomian) Sandstone, eastern portion of Kopet-Dagh basin, northeast Iran, American Association of Petroleum Geologist Bulletin, v. 76, p. 1200-1208. 9. Moussavi-Harami, R., Brenner, R.L., 1993, Diagenesis of nonmarine petroleum, reservoir the Neocomian (Lower Cretaseous) Shurijeh Formation, Kopet-Dagh basin, NE Iran, Journal Of Petroleum Geology, v. 16, no. 1, p. 55-72. 10. Ruttner, A.W., 1993, Southern borderland of Triassic Laurasia in northeast Iran. Geol. Rund, v. 82, p. 110-120. 11. Schmit, J.G., and Boyd, D.W., 1981, Patterns of silicification in Permian pelecypods and brachiopods from Wyoming, Journal of Sedimentary Petrology, v. 51, p. 1297-1308.

Maraveh-Tapeh N W E 2 Iran Garmab

Ashkhaneh Bojnourd

Chaman-Bid Jowzak Legend 1 F ش Toward Azad-Shahar ش Main City 1 Town : Village 1 Main Road , 0 Sidetrack 0 0 , 0 Fig. 1: Location map of the study area. Measured sections: 1- Jowzak; 2- Garmab. 0 0

1986

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

A B

0.42 mm 0.42 mm

C D

Oo Oo

Oo Oo

0.2 mm 0.42 mm Oo Oo

E F

0.2 mm 0.42 mm

Fig. 2: Silicification process in carbonate rocks of Chehel-Kaman Formation. A) Type 1, chalcedonies replaced in brachiopod shell. B) Type 1 and 2: bigger arrow shows chalcedony and smaller arrow shows macro quartz in vacant void; C) Type 3: micro quartz solution void; D) Type 4: facies selective macro quartz that formed in solution voids in Ooid grainstone; E) Type 5: macro quartz formed in fractures in three different directions; F) Type 1 and 5: type 5 crossed brachiopod shell and its silicification, bigger arrow shows type 5, smaller arrow shows type 1.

1987

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

Lower Cretaceous Deposites of Zagros :a Carbonate Ramp between Neo-Tethyan Continental Shelf and Arabian Platform Border

A.Amini Young Researchers Club, Islamic Azad University, Gachsaran Branch, Gachsaran,Iran.

A.Fahimi Geology Department, Science and ResearchCampus, Islamic Azad University, Tehran, Iran

Abstract: Fahlyan is one of the upper Khami group Formations with lower Cretaceous( neocomian-aptian) age. This Formation doesnot have any outcrops in south-west of Iran and embayment region .It is memorable because of reservior properties is memorable in geological point of view, sedimentary environments and Oil industry. This Formation studied in several subsurface sections of south Dezful embayment so far. Signs showing Fahlyan Formation had been deposit between Neotethian and Arabian platform. And confirming with existent Theory for this region.

Key words:Lower Cretaceous, Dezful embayment, Neotethian, platform

Introduction Iran has different depositional-structural regions, Zagros is one of these regions .Thereupon of no magnetism activities and existence of several source rocks, reservior rocks with good porosity and good cap rocks prepares individual conditions for manufacture and stach hydrocarbon.Then this region is the most petroliferous depositional extent of the world. Fahlyan is one of the reservior Formations of Zagros dependent on khami group with Neocomian age.In the study we can ducted ,it was found that good of by the geophysics and thin sections result of wells digged with National Oil Company of Iran in oil fields, on absence outcrop of this Formation in northern Dezful embayment.These studies accomplishing toward more reconnaissance of deposit conditions and other qualifications (Fig.1).

Jurassic to Cretaceous Neo-Tethyan Continental Shelf Overlying the Permian–Triassic platform successions, lower most Jurassic to upper Turonian strata form a number of megasequences that accumulated on a shallow continental- shelf, facing north and northeast toward Neo-Tethys (James and Wynd, 1965). Megasequences contain many petroleum source and reservoir rocks. The overlying units of megasequences all display gradual facies changes from coastal and sabkha-type clastic strata, evaporites, and dolomites on the southwest to shallow-water, high-energy-environment limestones, and finally to deep-marine, pelagic and hemipelagic lime mudstones and marls on the northeast.The uppermost Jurassic to lower Cretaceous Fahlyan, Gadvan, and Dariyan inner and outer shelf carbonates and argillites (Shakib, 1994), which are collectively about 750 meters thick in the central part of the belt (Dezful embayment), but thin to the southeast () to only250 to 300 meters in thickness (compare stratigraphic columns).

1988

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

Method of study The first stage includes data collection on relevant studiesdone on this Formation. Then laboratory works start and paying study of thin sections . Study of thin sections start from upper part of Formation due to mixing of samples takes from well cutting method and boundary of facieses ditinct with first incoming of new facies. Nomination of facieses done with expanded Dunham classification .After microscopic stage microfacies belths interpretating by using of standard microfacies of Wilson from both of wells. Next stage is modulating gained information with well logging data. Then drawing simulation of environmental model with softwares(Fig.6). Last stage containing deduction and presentation of results.

Explanation of microfacies Microscopic moduling and studies of constituent elements of each thin section onward percent of skeletal and none skeletal grains,cement and matrix lead to recognizing 17 microfacies in 4 groups and relating each of these groups to a subenvironment. Group A A1: Spiculite Wackestone (Fig2-A&B). A2: Pellet Bioclast Wackestone (Fig2-C). A3: Argillaceous Lime Mudstone (Fig2-D). Group B: B1: Pellet Bioclast Packstone (Fig3-A). B2: Intraclast Pellet Pack\Grainstone (Fig3-B). B3: Oolite Intraclast Grainstone (Fig3-C). B4: Pellet Grainstone (Fig3-D). B5: Tubiphytes Packstone (Fig.3-E). B6: Lithocodium Boundstone (Fig.3-F). Group C: C1: Benthic foraminifer Green algae Packstone (Fig.4-A). C2: Bioclast Pelloid Packstone (Fig.4-B). C3: Pelloid Bioclast Wackestone (Fig.4-C). C4: Fossiliferous Mudstone (Fig.4-D). C5: Pelloid Packstone (Fig.4-E). Group D: D1: Silty Mudstone (Fig.5-A). D2: Quartz arenite (Fig.5-B). D3: Pellet Intraclast Pack\Grainstone (Fig.5-C).

Sedimentary Environment and offer a model: After studying thin sections of Fahlyan Formation We can recognizine 4 subenvironments : open marine,shoal,lagoon and tialflat .Founded on Walter law and microfacies sequence this Formation show's shallow carbonate marine of ramp type (Fig.6).

1989

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

Open marine microfacies: This facies belth contain A1,A2 and A3 microfacies.Major allochemical grains of this microfacies are spong spicule,radiolarians,echinoides and brachiopods.Spong is one of the organisms that growing in deep marine and lake of oxygen and anaerobe conditions.So it is expected that these organisms be visible in lagoon and open marine.Radioler is a pelagic organism and because of their silica nature of shells can be visible in deeper c.c.d boundary.In total peresence of spnge spiculs with radiolarians , brachiopods and echinoid fragments represent open marine settings.acording to this study presence high content of micrite subsidiary condition is formed as a result of low energy and lower base wave. Besides existence silica allochems with secondary pyrite and high amount of clayminerals showing open deep or half deep marine conditions.

Shoal microfacies: This subenvironment consists of B1,B2,B3,B4,B5,B6 microfacies. Presence of none skeletal Grains as oolite, rounded pellet with intraclasts and flaked skeletal grains as lithocodium, tubyphytes,echinoids,bivalves showing shallow marine with high wave energy.However condition of make pellet is lagoon but precense of this grains in this facies shows reworking and redepositing in cutting shoal channels.Also absence micrite in Matrixe and constitute cement is significant of out wash micrite due to high amount energy and Formation carbonate cement between grains did possible.Moreover good sorting of sedimentary grains and presence of oolite represent shallow marine and high energy settings. Lithocodiums growing in shallow lagoonal and reefal seetings affected by moderate environmental stress(Flugel 2004).This organismes makeing patch reefs on inner part of shoal near lagoon.

Lagoon microfacies: This subenvironmet containsC1,C2,C3,C4,C5 microfacies. Low diversity of skeletal grains and high amount of pellet show a restricted environment.Moreover peresence of miliolid, textularia,dasycladacean green algae, halimeda and ostracodes are sign of lagoonal environmet.Other sign of Lagoon is micritization process. micritization process inclusive convertion shell of grains to micrite in depositional environment and syndeposit or immediatly after depositing .This process is sign of low energy and silent settings.Though Walter law determines these microfacies.

Tidal Flat Microfacies: This subenvironment consists of D1,D and D3 microfacies.Presence intraclast with lagoonal offspring and different size show an increased energy of environment in tempest conditions.Almost presence pseudomold of evaporitic minerals with regular and euhedral shapes and in the light of other adjacent microfacies representing depositing in tidalflat settings.Almost presence sand size quartz represent detrital Facies due to decrease relative sea level.

Conclusion: The findings of this study showed that fahlyan Formation Deposited as a ramp carbonat .Almost other studies upon this formation in other fields in Dezful embayment and Persian

1990

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

Gulf showed shallow depositional settings and with consideration in geographic position of Dezful embayment between Arabic platform And Orumieh- Dokhtar belth and folded Zagros (These two zones known as result of suture neotethian basin).These signs reveal that Fahlyan Formation deposited between Neotethian and Arabian platform and confirming existent Theory for this region ( Alavi, 2004).

References: 1- Alavi, M.Regional stratigrphy of the Zagros fold- thrust belt of Iran and its proforland evolution., American Journal of Science, Vol. 304, January, 2004, P. 1–20. 2- Colombie, C., and Strasser, A.,. Facies, Cycles and controls on the evolution of a keep-up carbonate platform (Kimmeridgian, Swiss Jura). Sedimentology, Vol. 52, P. 1207-1227(2005). 3- Feiznia,S. Carbonate Sedimentary Rocks,Astan Ghods Razavi,304p. 4- Flugel,E.Microfacies of Carbonate Rocks,SpringerVerlag,976p(2004). 5- James, G.A., and Wynd, J.C.,. Stratigraphic nomenclature of Iranian Oil Consortium Agreement Area. AAPG Bull. 49, No. 12, p. 2182-2245(1965). 6- Kheradpir, A.,. Stratigraphy of Khami group in Southwest Iran. O. S. C. I. Report, No. 1235(1975). 7- Lasemi, Y.,. Platform carbonate of Upper Jurassic; Mozduran Formation in the Kopet Dagh basin, NE Iran- facies-palaeoenvironments and sequences. Sedimentary Geology, Vol. 99, pp. 152- 164(1995). 8- Pawellek, T., and Aigner, T.,. Stratigraphic Architecture and gamma ray logs of deeper ramp carbonates (Upper Jurassic, SW Germany). Sedimentary Geeology,Vol. 159, p. 203-240(2003). 9- Sedaghat, R.,. The sedimentology of the Khami group, Lower Cretaceous, in east Khuzestan, Southwest Iran, Thesis submitted for the degree of Doctor of Philosophy in the University of London, 383 p(1982). 10- Tucker, M.E., and Wright, P.V.,. Carbonate Sedimentology. Blackwell, Oxford, 482 P(1990).

1991

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

Figure 1:Position of fields in middel east(a),Zagros(b) and Dezful embayment(c).

Figure 2: Spiculite Wackestone(A&B), Pellet Bioclast Wackestone(C), Argillaceous Lime Mudstone(D).

1992

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

Figure 3: : Pellet Bioclast Packstone(A),Intraclast Pellet Pack\Grainstone (B),Oolite Intraclast Grainstone(C),Pellet Grainstone(D),Tubiphytes Packstone(E), Lithocodium Boundstone (F).

1993

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

E ش ش

Figure 4:Benthic foraminifer Green algae Packstone(A), Bioclast Pelloid Packstone(B), Pelloid Bioclast Wackestone(C), Fossiliferous Mudstone(D), Pelloid Packstone(E).

1994

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

Figure 5: Silty Mudstone(A),Quartz arenite(B),Pellet Intraclast Pack\Grainstone(C)

Figure 6:Simulation of ramp environment and related facies in Fahlyan Formation.

1995

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

Oil Well Sand Production Control

Maryam Dehghani,

Petroleum Engineer – Iran [email protected]

Abstract In formations where the sand is porous, permeable and well cemented together, large volumes of hydrocarbons which can flow easily through the sand and into production wells are produced through perforations into the well. These produced fluids may carry entrained therein sand, particularly when the subsurface formation is an unconsolidated formation. Produced sand is undesirable for many reasons. When it reaches the surface, sand can damage equipment such as valves, pipelines, pumps and separators and must be removed from the produced fluids at the surface. Further, the produced sand may partially or completely clog the well, substantially lead to poor performance in wells and, ultimately, inhibiting production, thereby making necessary an expensive work-over. In addition, the sand flowing from the subsurface formation may leave therein a cavity which may result in caving of the formation and collapse of the casing. Sand entering production wells is one of the oldest problems faced by oil companies and one of the toughest to solve. Production of sand during oil production causes severe operational problem for oil producers. Several techniques have been used for sand production control in sandstone reservoirs. These techniques are divided into four groups including; standard rig operation with retrievable packer; tubing-conveyed string; coiled tubing and long zone/selective treatment. Several consolidating materials, such as, crude oil coke and nickel plating, have been used in the past by researchers. At present, the chemical binders, such as; phenol resin, phenol–formaldehyde, epoxy, and furan or phenol–furfural provides cementation. In this paper, we discuss sand control method for an oil well.

Introduction Most of the world oil and gas reserves are contained in sandstone reservoirs where sand production is likely to become a problem at some point during the life of the field. Sand production occurs during the hydrocarbon production from a well when the reservoir sandstone is weak enough to fail under the in situ stress conditions and the imposed stress changes due to the hydrocarbon production. The oil or gas flow transports the failed rock causing a variety of problems ranging from erosion of the surface facilities, to well integrity, and sand disposal. On the other hand, limited sand production has been proven to increase the productivity of a well and when tolerated it may eliminate altogether the need for sand control. Some of oil and gas fields are faced with sand production problem worldwide. Many of the world's oil and gas wells produce from unconsolidated sandstones that produce formation sand with reservoir fluids. Some reservoirs can produce several tons of sand in a day and it can be so severe that operators often choose to install down-hole sand control in all sand- prone wells. The standard, historical way of sand prediction, is to accept that if you get down to a particular pressure regime and rock strength, you will probably produce sand at some time during the life of the well. That pushes you towards a very conservative approach, where you go for installing lots of expensive up-front equipment as a precautionary default option.

1996

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

In sand-prone areas, we have a wide range of sand control options to choose from, including a variety of different down-hole sand screens and gravel packs which can be installed in production wells. But installing sand control hardware carries its own risks, so it is important to determine the correct sand control well completion option in each particular situation. Choosing the best method, lies in gaining an understanding of the underlying physics behind the flow of sand and liquid hydrocarbons. For this purpose, we must know different aspects of the fundamental physics of sand transport in multiphase flow - that is, flow containing liquids, gas and solids to be able to develop a sand control model. The model takes advantage of equations that describe the dynamics of fluid flow, and also draws on data about the way the rock behaves under different pressure regimes, to provide us with objective advice about the sand control options available to them and the best type of sand control completion to choose for production wells. The modeling work is also helping us to understand the effect of sand ingress into water injection wells and how best to deal with it. This can involve changing the design of the well, or adopting different well management procedures on injection wells. It can also involve taking advantage of sand control hardware such as expandable sand screens or other novel completion equipment. But the usefulness of the model is just as applicable to injection wells - wells used to pump water into a reservoir to maintain pressure and drive oil towards production wells. Without knowledge of sand control methods, the wells may have experienced excessive sanding and may have to be taken out of production earlier. The experiences results among other things that when it comes to managing production wells in sand-prone areas, we must go slow and steady. It's a bit like training to run a marathon. You begin training by starting slowly then you gradually build up your strength so you can run the marathon without injury. We take a similar approach to producing from sand-prone wells. By building up production in measured steps we are often able to improve the behavior of the sand by the way we produce from the well. In some cases, the best solution can be just to accept that some sand will be produced, and learn to live with it. Sand may pose a severe problem in offshore and onshore and also in gas fields. Problems that are associated with sand production include plugging of perforation tunnels, sanding up of the production interval, accumulation in surface separators and potential failure of down-hole and surface equipment from erosion. These problems can pose serious economic and safety risks. Although in one field, wells may all completed using a variety of standalone sand screen types, roughly half may producing sand and there may be consequent production losses, sanding may so severe that the well had to be shut in. We must have some information about the factors leading to sanding, enabling the field operators to modify activities that contributed to sand production. By managing those activities they were able to stop sanding in the wells altogether. In reservoirs such as heavy oil, tar sands and high temperature/high pressure reservoirs, controlling sand becomes even more difficult. In tar sand areas or when producing from reservoirs containing heavy oil, conventional sand control measures such as gravel packs and sand screens can form a barrier in front of the well-bore that blocks the flow of these highly viscous hydrocarbons, thus preventing the use of conventional sand control solutions.

1997

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

Gravel Packing Knowing the nature of the sand, which is best learned by examining cores, is an essential first step to control sand production from a well. Monitoring sand concentration in produced fluids can help identify "quick sands" (high and relatively constant sand concentration), "partially consolidated" sands (concentration fluctuates widely), and "friable" sands (taper off to nearly zero after a well has been on production for awhile). In order to limit sand production, various techniques have been employed for preventing formation sands from entering the production stream. One such technique, commonly termed "gravel packing", involves the forming of a gravel pack in the well adjacent the entire portion of the formation exposed to the well to form a gravel filter. In a cased perforated well, the gravel may be placed inside the casing adjacent the perforations to form an inside-the-casing gravel pack or may be placed outside the casing and adjacent the formation or may be placed both inside and outside the casing. Because of the nature of oil-field sands, slotted liners or screens by themselves (without gravel) are rarely effective in controlling sand production. For a successful gravel pack, it is necessary to: (1) size the gravel to stop movement of formation sand, (2) place gravel in a tight pack that has a radius as large as possible, and (3) maximize productivity while minimizing formation damage. Open hole gravel packing is common in vertical wells because it is easiest and usually less expensive than other options, although hole stability, screen plugging, and thief zones can be a problem. This method is generally limited to a bottom interval in multiple zone completions. The size of gravel pack sand that should be used depends on size of the formation sand. This is determined from sieve analysis, preferably from core samples (bailed samples tend to be large, produced samples tend to be small). Gravel pack sand is normally sized to achieve a suitable grain size ratio. There is a trend towards using larger sizes. Screen or slotted liner openings should be no larger than the smallest gravel pack sand diameter. Pre-packed screens and liners must be appropriately sized. Three basic tools are used in gravel packing operations: (1) packer/crossover tool assembly, (2) over-top tool assembly, and (3), in some cases, port collars. Some are completion tools that remain in the well after the gravel pack is complete. On the other hand, service tools are used while placing the gravel pack but then are removed. There are three basic gravel pack processes: (1) High Rate Water Pack, (2) Fracture Pack, and (3) Horizontal Gravel Pack. Fracture Packs are a combination of a fracture treatment and an annular gravel pack. A successful Fracture Pack must not only stop sand movement, but must create a wide fracture that is held open by a high permeability extending through the near well-bore zone, importantly not making contact with nearby zones that contain unwanted fluids. A High Rate Water Pack, which pumps water and sand at high rates creating short fractures, maximizes gravel placement in the perforations. Treating pressures may or may not exceed fracture pressure. High Rate Water Packs are typically used where the completion is near water or gas contacts and there is a shallow radius of near well-bore damage combined with relatively uniform sand quality and permeability. In contrast, Fracture Packs, which create much longer fractures, are used where sands are laminated, where fines migration potential exists, or where deep formation damage is known or suspected.

1998

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

In high angle and horizontal well-bores, any formation that will not collapse while drilling a long horizontal, should be strong enough to not produce sand. This is also true with removing the drilling equipment and running a liner/screen. Sand problems occur with excess water production, too much pressure reduction, or with high drawdown (high production from short intervals). Just as with vertical wells, slotted liners or wire wrapped screens should be used in conjunction with gravel packing. Un-gelled brine is typically used. Special pre-packed screens and down-hole filters, which are sometimes used in horizontal wells, can be susceptible to plugging and collapse. Before installing pre-packed screens or liners, it is important to apply a thin coat of acid soluble materials, waxes, or wax-polymer blend to them to reduce screen/liner plugging. When designing horizontal gravel packs, it is important to define the allowable pump operating ranges. Pump rate must be high enough to exceed the rate of fluid loss and to push dunes of gravel to the end of the screen. This system uses small diameter tubes strapped along the outside of the screen that allow gravel to be pumped at high velocities. A controlled viscosity fluid is used to suspend gravel and aid its transport.

Oil Well Sand Control Screen Pipe Composite grading sand control screen adopts peculiar grading sand control design and organic combination of surface filtering and deep filtering to realize double precision of single screen. It is a new design breach in mechanical sand control field. In the meanwhile, it has characteristics such as high penetrability, high strength, high deformability, high reliability and strong corrosion resistance, so it is the most effective sand control product at present. External protective sleeve with bridge side discharge orifice (optional). It can protect grading sand control filtering layer excellently during transportation of product and case-off process and prevent influence to actual anti-sand effect caused by puncture and damage of anti-sand filtering layer. It can effectively avoid direct erosion damage of flow to grading sand control filtering layer during production process of oil and gas well and extend service life of screen. Central tube of screen shall adopt standard oil tube and casing. Central tube adopts helical perforation form to reduce opening area of cross section and retain strength of central tube as much as possible on basis of guarantee of integral area of passage. Sand is blocked out of screen and oil, gas or water in stratum can pass aperture of filtering layer and orifice on central tube to enter into screen to realize the purpose of sand control.

Permeable Solid Barrier A method for treating a sand formation adjacent to a bore hole forms a permeable solid barrier which restrains the movement of sand particles while maintaining the permeability of the formation. The method includes the step of forming a consolidation fluid containing an asphaltene and a hydrocarbon solvent such as naphtha. The consolidation fluid is injected into the sand formation to saturate the sand in a zone around the bore hole. This is followed by injecting an oxygen-containing gas for a period of time. In one embodiment of the invention, the oxygen concentration of the effluent gas is monitored and the injection of oxygen- containing gas is continued until the oxygen concentration of the effluent gas is equal to the oxygen concentration of the injected gas.

1999

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

Results We must adopt new production practices for managing sand. These involved maintaining hydrocarbons production at a level that is set over the long term to avoid reservoir damage, rather than pushing the wells to the point where sanding occurred followed by a break in production. As a result of adopting these recommendations, oil production has improved and sand production has been greatly reduced. While it is important to effectively prevent sand production, it is equally important to do so in a way that does not hinder a well‘s productivity. This dual goal requires specialized sand control completion practices to allow hydrocarbons to be produced without formation sand.

References 1- Hower et al., "Advantage Use of Potassium Chloride Water for Fracturing Water Sensitive Formations", Producers Monthly, Feb. 1966. 2- Dias-Couto, L.E. and Golan, M.: ―General inflow performance relationship for solution-gas reservoir wells‖ J.Pet.Tech, 285-288, Nov. 1981. 3- Frear, R.M. Jr., Yu, J.P. and Blair, J.R.: ―Application of nodal analysis in Appalachian gas wells‖ SPE number 17061, presented at the SPE eastern regional meeting held in Pittsburgh, Pennsylvania, 1987. 4- Golan, M. and Whitson, C.H.: ―Well performance‖, IHRDC publisher, 1986. 5- Holmes, J.A.: ―Modeling advanced wells in reservoir simulation‖ SPE number 72493, Distinguished Author Series, 2001. 6- Klins, M. A. and Majcher, M. W.: ―Inflow performance relationships for damaged or improved wells producing under solution-gas drive‖ J.Pet.Tech, 1357-1363, Dec.1992. 7- Mukherjee, H. and Brill, J. P.: ―Liquid holdup correlations for inclined two-phase flow‖ J.Pet.Tech, 1003-1008, May 1983. 8- Tarek, Ahmad, ―Reservoir engineering handbook‖, 2rd, Golf professional publishing, 2001.

2000

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

Identification and Analysis of Fractures Exiting in one Well in SE Iran using by FMI Image Log

ghasem Saedi*,bahman soleimani1,abass charchi1, shahram Taghavipur2

*Msc student, petroleum Geology, Shahid Chamran University, , Iran

1 geology department, Faculty of Earth Science, shahid chamran university,ahvaz

2National Iranian South Oil Company (NISOC) [email protected] Abstract: Permeability is one of the most important factors in reservoir production which has a direct relation with fractures in carbonate reservoirs. Therefore determination of fracture density, strike and dip direction, the amount of the opening, their distance from each other being close or open and finally representing of suitable pattern of reservoir fracture, can help us know about production programming of the oilfield. The main aim in this study is the determination of number and directions of fractures, their relative frequency in different zones, measurements of dip and strike of layering, local stress and recognition of other geological features available in drilled formation using by FMI log interpretation in a well of the lali oilfield, and also evaluate about the capability of this tool via correlation between archived data from FMI image log and core observation and thin section study data. In this study due to the lack of mud loss data as an indirect method diagnosis of deep reservoir fracture, FMI image log was used to identify small-scale fractures of the Asmari reservoir fractures type in this Oil-field. The result of this study are important in of operation acid Frac and geomechanics . the present study indicates that average slope of layering in Asmari reservoir based on 117 logs read from FMI, about 8◦ towards the N35W and S35W. Major fractures is open fractures with about about 78◦ towards the N35W and S35E and theirs strikes N55E-S55W along N55W-S55E. Minimal stress affected on the field is along the shear fractures (NE-SW) determined. On the other hand maximum stress is to consistent to the process of formation of the Zagros Mountains along the NW-SE trend. Hydraulic fractures (induced Fracture) created by increasing of the mud column pressure on the hole infact their forms in those location of maximum stresses in the hole and having NE-SE trend.

Introduction The Asmari formation (Oligo-Miocen) is a main petroleum reservoir of Iran which is consisted of calcite and dolomite. Petroleum production potential of the Asmari reservoir is about 85% of the crude oil due to abnormal Vuggy prosity type resulted from Natural Fractures. Therfore the study of the fractures in the Asmari Reservoir is a serious subject up to now[1].Generally in the Fracture Reservoir, The Fractures controls the reservoir behavior[2].if the fractures are open,they can be the conduits to petroleum migration and so resulted to developed a highly production zone; with the permeability more than 10000 md[3,4]. core Analysis is also a common Method to identify the small-scale fractures of the well, but there is some limitations is the core procedure such as high expensive, unidirectional and low recovery coefficient in fractured zone, Thus this such cases to use Image Logs to study the subsurface Fractures[5]. Image log data complements core hole data and can reduce the amount of coring required by 75% resulting in significant savings to drilling programs in

2001

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 terms of project cost and time[6]. It is cleared that fracture study and evaluation in any oilfield can be helpful in the complementary stage of the well ,the determination of perforating depth, field development, directional drilling well program, fluid injection zone and fracture modeling.

Geological position Area under study: Lali oil-field is located in the region of northern Dezful at 112 km northeast of Ahwaz(Figure 1).this anticline is an asymmetrical structure with NE-SW trend and southern flank dip is higer than northen flank, and its causes to change the axis to follow west trend in norther part and souther trend in the west.the Asmari reservoir is divided to 7 zones based on archived petrophysical data.

Methodology: The lack of mud loss data, production rate and other indirect documents of the fracture presentation led to determine small scale fractures in the reservoir zones of the Asmari formations and fracture classification(open, closed, vuggy, induced and so) using FMI Image Log data. in the FMI Image Log , layer boundary maybe clear or disclear, Therefore dip value calculation from the first layer boundary is possible and classified in to:(1) High confidence bedding dip;(2) low confidence bedding dip. in the image, lines which intersect layer boundaries and indicating high resistivity are layers boundary. this line as also define the geometry shape and the thickness of the layers. the line simply present layer boundary which may be planar, concave ,convex ,wavy or irregular with load casts or erosion surface[7&8]. FMI Image Logs of the wells drilled with water-based mud are able to differentiate fracture types(open, closed, vuggy, induced and so).Therefore the tool programerized based on fractures resistivity. open fractures filled by mud are dark color but closed fractured filled by secondary materials are presenting light color.

Discussion: Based on FMI Image Log as an power full tool to describe the subsurface fractures in the Asmari formation of the lali oil field, dip of bedding are varied from 30ْ NW to 60ْ NE(figure-2). But dip average estimated 8ْ based on 117 reading of the FMI Plots. In this well in The Asmari Reservoir as heterogonous reservoir revealed 98 open fractures (open and 58 sub-open fractures).their dips change from 54-86ْ with the azimuth of S30E and S35W and their strike N55W-S55E and N60E-S60W(Figure-3). it is also observed 54 closed fractures with the dip of 62-84 toward N63W/S25E with the strike of N27E-S27W and N65E- S65W.With comparing of density and number of fractures, it is calculated that high density is in 1,2and7 zones since zone-1 contains 40 open fractures in the interval of 2074-2088 m; zone-2 having 17 open fractures and zone -7 has 29 fractures(figure-4). FMI Image Log data revealed the fractures produced by borehole breakout the well ellipsoid in the less tension sides. In the well cross section the borehole breakout are indicating NE-SW trend, this fractures are indicated of less tension in to the wellbore. (induced fracture) which generated by mud pressure are observed in high tension over the well side with NW-SE trend. This trend can be some important during Acid Frac and Geomechanic stage.

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

Conclusions: FMI Image Logs plots of the Asmari Reservoir revealed that dip and bedding boundary can be grouped as (1) High confidence bedding dip;(2) low confidence bedding dip mean is 8ْ toward N30W with the strike of N60E-S60W. All open fractures(98 numbers) are presenting -variable dips between 54-86ْ with the azimuth of S30E and S35W and their strike N55W S55E and N60E-S60W. closed fractures are indicating dips range 62-84 toward N63W/S25E with the strike of N27E-S27W and N65E-S65W. Open fracture are mainly distribute in 1,2 and 7 zones (Because of the presence of the dense lithologies such as dolomite and calcite derived from conventional petrphysical logs likes PEF,NPHI,ROHB),since zone 1 contains 40 numbers, zone 2 has 17 and zone 7 has 29 numbers.

Reference: [1]- Khoshbakht .F , Memarian .H, Mohammadnia.M;2009; Comparison of Asmari, Pabdeh and Gurpi formation's fractures, derived from image log- Journal of Petroleum Science and Engineering 65–74 [2]- Nelson, R.A., 2001, Geologic Analysis of naturally Fractured reservoirs, Gulf publishing , Houston , Texas , Contr. In petrol . Geology & Eng., 2nd ed ., 332p. [3]-Rezaeei, M.R; 2006, The book of petroleum Geology, alavi propagation; 472p. [4]- Haller, D., Porturas, F., 1998. How to Characterize Fractures in Reservoirs Using Borehole and Core Images: Case Studies. Geological society, vol. 136. Special Publications,London, pp. 249– 259. [5]- Khoshbakht .F , Memarian.H, Mohammadnia.M;2009; Comparison of Asmari, Pabdeh and Gurpi formation's fractures, derived from image log- Journal of Petroleum Science and Engineering 65– 74. [6]- Stroble. R, 2009; The Value of Dipmeter and Borehole Images in oil sands Deposit A Canadian Study. [7]- Prensky.S.E,1999; Advanced in Borehole Imaging technology aapplication. [8]- Serra,O.,1989, Formation micro scanner image interpretation., 2 nd., ed., schlumberger educational services, 117p.

Nar LAB-E-SEFID

Palangan Lali Zeloi Andakar MASJID-I- SULEIMAN

( Figure-1): The geological map of the lali oil field.

2003

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

RosetteAzimuth Strike

RosetteAzimuthDip

Dip Inclination Histogram InclinationDip

( (Figure-2): structural dip average for all bedding in the under study well based on FMI.

( Figure-3):The Distribution of the all open fractures with dip, azimuth and their strikes in the under study well.

2004

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

F r a c t u r e

d e n s i t y

, z o n e - 1 , 2

F r a c t u r

(Figure-4): the final schematic of all layers in the under study reservoir on the bases of caliper,GR,FMI,PEF,NPHI and,ROHB conventional logs .

2005

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

The usage of hard unites of Mozduran Formation as a wall in Ardak dam (in Northwest of Mashhad)

Hossein Abbasnia*, Ali Asghar Aryaei

Department of geology, faculty of science, Islamic Azad University- Mashhad branch, Iran [email protected].

Abstract Mozduran formation has known as of uppermost rock unites in Jurassic and begin of cretaceous period in Kopet-Dagh in northwest of Iran. This formation shows the high cliff in hard unites from Triassic to Neogen. The changes of depth and qualification of sedimentary basin causes cyclic forming of different sedimentary rocks like as marl, shale, limestone and sandstone. In Ardak area as reason of good morphology and qualification for forming barrier by using Kashafrood and Chaman-Bid formation rocks as of reservoir and base cliff limestone Mozduran as of wall Ardak barrier has been built.

Keywords: hard unites, Mozduran, barrier

Introduction Geological study of Dam site is one of the most important steps in civil projects. Situation of Dam reservoirs in terms of morphology, permeability, chemical and physical pollutions and capacity. In addition, structure of Dams is as important as situation for Dam engineers (Stability, lithology, tectonic and geological formation). Ardak Dam located in the North- West of Mashhad (50 km). This Dam built on Chaman-Bid and Mozduran formations. We studied the application of rock units in this Dam.

Geological Setting There is a series of parallel mountains in North of Kashfrood-Atrak graben. Trend of mountains is as same as folding. They called Kopet-Dagh and involved of different sediments like shale, sandstone and limestone. Chaman-Bid Formation consists of limestone, marl and shale which deposited over each other with 3 m width and several kilometers lengths. Mozduran Formation consists of limestone, shale and shaly limestone. It is constitute 1.8 percent of reservoir area.

Geology of Dam reservoir: A- Geomorphology: Dam reservoir situated in Chaman-Bid formation that formed core of Mian-Morgh anticlinal. The sediments involved marl and limy marl laminate. Effect of erosion on these sediments is more considerable than Mozduran Formation so, they seem like hills. In general, lithology of this area had strong affect on geomorphology of Dam area.

B- Lithostratigraphy Based on researches, this field is located in Kopet-Dagh sedimentary basin. Kopet-Dagh sedimentary basin located in North of Khorasan and Turkmenistan. We see the Binalood

2006

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

Mountain in the South, Tooran plate in the north and Eshghabad fault (310-315 degree) as a suture line (it separates Kopet-Dagh zone from Tooran plate). As a sedimentary basin, Kopet-Dagh basin involved thick sedimentary layers (8000 m) without significant stratigraphic gap however; facies variation is considerable for geologists. From geological time scale view, sediments had been deposited from Jurassic to Miocene, it means after early Cimmerian orogensis (collision between Iran and Tooran plates).

C- Tectonic: However tectonic had main role in creation of geomorphologic structures of the field, lithology is as important as tectonic in terms of geomorphology determination. As we mentioned, Ardak dam is located near core and southern limb of Mian-Morgh anticlinal. Trend of anticline axis is NW-SE, layers dip in southern limb is 60º and for northern limb is 50 º. Except this anticlinal, we do not see an important tectonic activity and structure like fault in reservoir area.

Conclusion The results involve: A- Calcareous units and shaly- lime unit of Chaman-Bid formation in the dam site cause suitable morphology and also low permeability for dam reservoir. B- limestone, dolomite, shale and marn units of Mozduran formation cause stability in the wall rock and as a result it is suitable for making dam. C- The big geological problem for engineers is fault in general, tectonic activity. In fact, faults caves a problem that we called it escape of water; now this problem to be solved in this area because of sedimentary units deposition. Chaman-Bid and Mozduran formation settle sequently thus water can not carry out through at the layers easily.

References 1- Afshar Harb. A. 1373. Geology of Kopet-Dagh, Geological survey of Iran. 2- Geology of Iran, Darvish zadeh. A., Amir Kabir publishing, 961 pp 3- Geological report of Ardak Dam projects, Abpooy consulting engineers, 1378.

2007

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

The Effects of Sedimentary Conditions on Geometric Stable Section of Karvandar River

Hossein Aqebat Bekheir1, Mehdi Azhdary Moghaddam2, Ali Ahmadi3

1) Dept. of Geology, Azad University, Zahedan-Iran

2) Asst. Professor, Dept. of Civil Engineering, University of Sistan and Balouchestan, Zahedan-Iran

3) Asst. Professor, Dept. of Geology, University of Sistan and Balouchestan, Zahedan-Iran

Abstract: One of the main problems in rivers and streams management is erosion and sediment issue. Annually large amounts of sediment enter in surface transfer systems and filling the dam reservoirs which causes tension on water resources management. The study zone includes catchment of Karvandar River which is located in north of Irandegan plain and in the vicinity of Sibe-Sooran, Khash and Poshtkooh plains in Sistan and Balouchestan province. This zone is in 20°34 ´to 28° 2 ´latitude and in 60° 35 ´to 61° 14´ longitudes. The surface area of this catchment is 2128 km2 that 1789 km2 of it is covered by altitudes and the remaining is plain. Existence of sensitive formations to erosion with the lack of appropriate use of lands causes entrance of sediments into Karvandar River flow. For this research using topographic maps of the region and river path physiographic of the catchment were studied. Then morphology, lithology, bed and lateral erosion, river regime, location and extraction of quarries, vegetation and also the information of hydrometric station were collected. The results show that vegetation of the zone is bushed-germanous that has little effect on prevention of erosion and movement of sediments to the downstream of the river. Generally in 95% of Karvandar catchment area, parameters of geology, vegetation, harvest quarries, early erosion (susceptibility to erosion) is related to formation and development of on geometric stable sections and river morphology that indicate direct and indirect effect of mentioned factors on determination of erosion type, state of sediments carrying and sedimentation in this catchment area.

Keywords: erosion, sedimentation, river regime, stable section, effects of environmental conditions, Karvandar

Introduction Most of civilizations are formed in the sides of rivers. Flooding and inundation of rivers are natural process of the earth that can change and destroy different aspects of human lives such as vital, economic and social. from the centuries ago, human have found special facilities anticipate to prevent of desolator effects of flood water, the establishment of dam on the rivers, construct parapet and fence of stones, plant vegetables and small trees across the rivers for the decrease of prejudicial effects of flood water and the destructive effects of rivers. In the developing countries, such as Iran, because of special regional situation and non- observance and recognition of nature, in the past and present rivers were stage of flowing disastrous and injuries flood water. Statistics shows that in the zone of Karvandar take place big flood water in date of 2-07-2007 with discharge of 10.051 m3/sec and on 14 April 2008 with discharge 30 m3/sec.

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

Therefore, for the better recognition of river and prevention of floods damage understanding of river regime is necessary. Also knowledge about conditions of climate, geology and morphology of the studied zone and hydrology of flood water help to have better view of it. According to these elements, one can recognize better the points of erodible and sedimentation and also think about prevention of these and offer a suggestion. For better perception of erosion in rivers and its catchment, first one should consider different kinds of erosion, the elements that effect on erosion and function and its effects. For the most important of erosive elements in each zone, one can attribute to climate, time, geology, and water river regime and topography situation. In considering of climate, different parameters effect that their most important are temperature, precipitation, and wind. In geology and also lithology catchment and techtonique there are two elements which control erosion i.e. in topography, slopes and lowness and highness has important function, in duration the collection of these elements are the principal elements of erosion in a catchment.

Research procedure The goal of this study is recognition of Karvandar River regarding to hydrological information. Therefore, there are needs to the basic meteorological, hydrological and geological studies. In meteorological studies one can consider different parameters such as, temperature, rainfall, wind and so on. In hydrological studies river discharge, river flood and physiographical considerations need to be studied. Generally taking sample of rivers accomplished from left and right river bank and other places that may need the middle part of river. After tests such as granoulometry and drawing their charts based on the statistical tables, statistical characteristics of river sediments were studied. Investigations of morphology of river considering satellite and topography maps were examined. Also classification and division of river from the aspects of shape appearance and erosion were investigated. Finally, based on the drawn conclusion, several suggestions to prevent rivers erosion as well as decrease of desolator effects of flood water were presented.

Geographical condition of studied zone The studied zone is including river catchment with the geographical zone of eastern longitude 260000 to 350000 and 330000 to 3110000 (OTM). The towns that are near to this zone are from north is Khash, south Iranshahr, and from west Saravan and Zaboli. Figures 1 and 2 can show the situation of the studied zone as well as the accessible roads. The distance of Karvandar catchment, center of Sistan and Baluchestan, Zahedan is about 240 Km. The studied zone is located in the middle of the khash-Iranshahr connections road. Because of existence of large amount of connection roads, which are mostly for villages this zone there one can conclude that almost access to the most area of this catchment is possible.

PSIAC Experimental Procedure This procedure is presented for calculation of soil erosion and production sediment of the dry and semidry area of west the United States. PSIAC was used for the first time in Iran in 1973 in Dez catchment. Since it has a relatively good precision then it was used in other catchments such as Dokhaharan, Kahir, Maroon, Halilrood, Saravan, Wawzon Valley. Recently this procedure is used in most water and soil plans to evaluate erosion and sediment production. In

2009

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

PSIAC procedure, effects of 9 important and effective elements in soil erosion and production of sediment in catchment (see table 1) were evaluated and depending on intensity and weakness of each element, one can assign a relative value to it and taking achieved total value for different elements, provides the amounts of catchment sediment use and this method is expressed in the following: Qs = 38.8 EXP0.0353R i.e. R: achieved total value for different elements of erosion and Qs: erosion potential m2/km2.

Discussion and Conclusion: Regarding the present study, experiments in Karvandar zone, following conclusions are achieved: 1- In Karvandar catchment at upstream, the average amount of gravel, silt high amount of sand, and little amount of silt and clay were observed where as at down stream decrease in gravel and increase in silt and clay were measured. Therefore, decrease in gravel and sand and increase in silt caused by slope of 45 % zone of the catchment. So, statistical parameters from upstream to downstream were change in the following manner: mid from -2.24 to 8.3; mean from -1.6 to 3.06 increased; skewness from 1.1 to 2.92 (very bad to bad); and kurtosis curves from -2.4 to 2.96 . 2- Based on Folk classification (1974); most of sediment textures in this zone are sand muddy gravel. 3- In this zone the mid and mean of sediment from the upstream to downstream were increased that which is symptom of existence of a bed gravel and sand at upstream and a silt bed at downstream the river. 4- Rate of negative curvature of some river sediments from this zone were caused by existence of a great amount of large particles, because with effect of river flooding the small particles were washed and displaced and positive curvature of sediment were resulted by a large amount of suspended materials that they were kept with larger grains. 5- Regarding to decrease in size and diameter of grains of sediment in this zone, the form of zone were change separately with a sandy-Gravel bed. 6- Regarding to there samples according United state conservation service standards were tested and the results showed that about %78 of the sediments of the studied zone, varied with skewness from bad to very bad and their resistances to erosion were very low.

References

1. رفاَی حسیىقلی )1382(، فرسایص آتی ي کىترل آن، داوطگاٌ تُران.

2. علیسادٌ امیه)1382(، اصًل َیذريلًشی کارتردی، داوطگاٌ امام رضا مطُذ.

3. فیريز، ع. ر. ي ایًب زادٌ، س. ع. ي حمسٌ قصاتسرایی، م.، )1387(، "ريش صریح طرح مقاطع پایذار ي ارزی اتی آن در سٍ ريدخاوٍ مىتخة کطًر"، مجمًعٍ مقاالت سًمیه کىفراوس مذیریت مىاتع آب ایران، داوطگاٌ تثریس، تثریس، ایران، 25-23 مُرماٌ، مقالٍ 10523

2010

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

4. فیض ویا سادات)1387(، رسًب ضىاسی کارتردی تا تاکیذ تر فرسایص خاک ي تًلیذ رسًب، وطر داوطکذٌ علًم کطايرزی ي مىاتع طثیعی گرگان

5. گسارش آماری ياحذ مطالعات ضرکت سُامی آب مىطقٍ ای سیتان ي تلًچستان، )1387( 6. Ackers, P. (1972), ―River Regime: Research and Application. Hydraulic,‖ Wallingford. 7. Ackers, P. and White, W. R. (1990), ―Sediment Transport: the Ackers and White theory revised,‖ Report. 8. Ackers, P. and White, W. R. (1973), ―Sediment Transport: New Approach and Analysis, ― Proc. ASCE, Vol. 99,HY11, pp. 2041-2060. 9. White, W. R., Paris, E. and Bettess, R. (1986), ―River Regime Based on Sediment Concepts,‖ Hydraulic research. Wallingford. 10. White, W. R., Paris, E. and Bettess, R. (1980), ―The frictional Characteristic of Alluvial Streams: A New Approach,‖ Proc. Inst. Civil Engineers, Vol. 69, (2), pp. 737-750. Table 1. Related values of PSIAC method

zone distinction of karvandar No. parameter characteristics of the study zone distinction catchment

1 The surface geology kinds of stone, rigidity of stone, measure of cracked 0 - 10 7

texture, measure of lime salinity, organic material, 2 soil 0 - 10 8.2 contraction, expansion percent, of gravel

alternation, intensity and duration of precipitation, measure 3 climate 0 - 10 5 of snow, to freeze melting

4 surface flow volume in surface unit, peak flow 0 - 10 8

lowness and highness measure of slope, lowness and highness the measure of 5 0 - 20 10 (topography) developing of cone and flooding field

6 earth vegetation, stone, the vegetation under trees, debris -10 - +10 -9

percent of agriculture lands, intensity of grazing, the 7 usage of earth -10 - +10 -9 cutting trees and building road

present situation of erosion furrows and moats, stumbling land, sedimentation, windy 8 0-25 10 (In high land) in canal

river erosion and the the side erosion and bed, depth of flow, active Headcuts 9 0-25 9 sediment and vegetation in flood ways

sum of distinction -20 - +130 53.8 special erosion (m2/km2) year 1040.91 surface of Karvandar zone (km2) 1765 volume of annual sediment (m3) 1837209.12

2011

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

Selection of the Optimum Production Scenario for One of Iranian Offshore Oil Reservoirs

M. Allahayri*, M.Abbasi** and A.Sanati* *M.Sc. in Petroleum Engineering, Faculty Staff of Azad University of Tabas, Iran [email protected]

**M.Sc. in Petroleum Engineering, Petroleum University of Technology, Ahwaz, Iran

***M.Sc. in Petroleum Engineering, Faculty Staff of Azad University of Tabas, Iran [email protected]

Abstract Effectiveness of two enhanced oil recovery techniques on recovery of Soroosh oil field, an Iranian offshore oil reservoir is investigated and compared. The approach used is the numerical reservoir simulation by means of a well-known numerical reservoir simulator, Eclipse, and the real full field model. Water injection and immiscible gas injection processes have been simulated and compared in terms of ultimate recovery factor. It was found that natural production of oil by depletion and water drive from aquifer will result in very low ultimate recovery factor. Simulation runs also showed that waterflooding can be efficient just for upper high permeability layers which contain lighter oil. Finally, from the gas injection simulation runs, it was found that immiscible gas injection can enhance ultimate recovery to 27% which is higher than that of waterflooding. The decline rate of production during gas injection was slower than that of waterflooding, which results in higher oil flow rate and ultimate recovery.

Introduction The initial oil in place (IOP) for Iranian heavy oil reservoirs is estimated to be 85.77 MMMSTB. Also, Iran has the world‘s second largest reserves of conventional crude oil of 133 MMMSTB. Therefore it is necessary to undertake extensive study to find suitable enhanced oil recovery methods to maximize the recovery of such these large amounts of reserves. In general, the important deposits of heavy crude oil in Iran are limestone and dolomite which range in age from Cretaceous to Eocene. Heavy oil traps are mainly anticlinal structures, located in the southwest part of Iran (Zagros area). Some of important Iran‘s heavy oil reservoirs are as follows: Kuh-e-Mond, Zaqeh, Sousangerd, Paydar, West Paydar, and Soroosh. In this paper, Soroosh oil field is taken into consideration. Water injection and immiscible gas injection schemes are investigated and compared in terms of recovery factor. In addition, the natural production of oil by pressure depletion will be also taken into consideration as a basis for comparison.

1. Theory 1.1 Theory of Heavy Oil Production As defined by the U.S. Geological Survey (USGS), heavy oil is a type of crude oil characterizedby an asphaltic, dense, viscous nature (similar to molasses), and its asphaltene (very large molecules incorporating roughly 90 percent of the sulfur and metals in the oil) content (Szasz and Thomas, 1965). It also contains impurities such as waxes and carbon

2012

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 residue that must be removed before being refined. Although variously defined, the upper limit for heavy oil is 22 °API gravity with a viscosity of 100 cP. Some heavy oil production can be accomplished via conventional methods, such as vertical wells, pumps, and pressure maintenance, but these methods are considered highly inefficient. Other technologies being used to recover heavy oil include, but are not limited to cold heavy oil production with sand (CHOPS), vapor extraction (VAPEX), and thermal in-situ methods. The main oil-related challenges involved in production are gravity and the viscosity of heavy oil (Szasz and Thomas, 1965). Iran has the world‘s second largest reserves of conventional crude oil at 133 ×109 barrels, although it should be noted that both Canada and Venezuela have larger reserves if non- conventional oil is included. Iran is the second largest oil holder globally with approximately 10% of the world‘s oil. In Iran, the proved and probable heavy oil reservoirs are mostly located in southwestern part of the country. These reservoirs are highly fractured, and the rocks are of different mineralogy, e.g., marly limestone, dolomite argillaceous limestone,etc. Based on the studies performed so far by National Iranian Oil Company the OIP for Iranian heavy oil reservoirs is estimated to be 85.77 MMMSTB.

1.2 Description of Soroosh Oil Field The Soroosh field, located 80 km from Kharg Island in the Northern Persian Gulf, was initially developed in the 1970‘s and produced 86 MMbbl until it was damaged in the Iran- Iraq war. Oil production takes place by natural depletion of the reservoir and also water drive from aquifer water influx. The field began redevelopment by Shell in 2000 under a buy back contract. It will be developed by 10 ESP horizontal wells drilled into the crest of the Burgan- B reservoir to produce a plateau of 100,000 bbl/d using depletion and aquifer drive The Soroosh Burgan-B is at a depth of 2200 m and the high quality (more than 4 darcies) target channel sands are generally between 10 to 40 m thick. The reservoir has a 140 m column of viscous oil of varying quality both areally and with depth, with the more viscous oil found deeper in the reservoir: The distribution of the oils is not fully established, but over the upper 80 m the viscosity generally deteriorates from 15 cP to 50 cP and is a factor of 10 or more higher towards the WOC. Past and currently planned development is of the Middle Cretaceous Burgan-B Formation, the main reservoir interval, which ranges in thickness across the field from 52 to 73 m. The Burgan B target interval comprises well connected channel sands of 25- 29% porosity and permeability in the range of 5-11 Darcy. Fluid properties in the reservoir vary with 20 °API degrading to 15 °API oil over the upper 50 m of the reservoir (23 cP to 70 cP), and heavy oil and tar observed towards the WOC at 2272 m. The Burgan Formation is underlain by the Basal Shale and low permeability carbonates of the Shuaiba Formation and as a result only a flank aquifer is expected. Regional correlations suggest that the Burgan-B Reservoir is very extensive and that a volumetrically large flank aquifer exists. It has been established from well tests that the oil quality varies through the field and it appears that this is at least partially depth dependent. The higher viscosities have a major impact on the ability of the oil to move through the reservoir and at the oil-water contact they

2013

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 appear to act as a significant baffle suppressing aquifer support and influx. The uncertainty currently assumed in the viscosity model represents the largest contributor to the uncertainty range on the reserves. To illustrate the expected viscosity distribution with depth a breakdown of STOIIP per depth interval is given in Table 1 from the Soroosh Subsurface Development Review. 2. Production Strategies Due to the very adverse mobility ratio between oil and water, the 10 well development plan is currently predicted to achieve a further recovery of only around 500 million bbl over 25 years, or a total recovery factor of only some 7% of the 8.5 billion bbl of STOIIP. An option is a flank water injection scheme which would aim to replace voidage at up to 180,000 bbl/d. The scheme was envisaged as a pressure maintenance mechanism rather than to improving sweep efficiency. As such, it would increase recovery within a 25-year period, but only by the order of some percentage points. In order to make a significant improvement in the recovery, sweep efficiency must be improved. Sweep efficiency could be improved by dense drilling of a pattern waterflood, however the gross throughput of such a scheme would need to be enormous to reach high recoveries. Gas Oil Gravity Drainage (GOGD) may be a much more suitable mechanism to improve recovery in Soroosh. A peculiarity of the Soroosh field which makes gas injection attractive is that the oil is very undersaturated with a bubble point pressure of around one fifth of the initial pressure. In order for GOGD to be effective, the process must be occurring over a reasonable column height with a high vertical permeability: this may be practicable in Soroosh with its approximate 30m of highly permeable sands. A total number of 8 wells are open to production. The simulation was run using the full field model for 30 years with the same production history and well completion data as before redevelopment program. The total oil production 8 7 was found to be 1.82×10 STB oil and gas production of 3.12×10 SCF. Based on the initial 9 oil in place of 2.8×10 STB, natural production will recover only 6.5% of the initial oil in place after 30 more years.

2.1 Gas Injection Scenarios The gas injection scheme was set up. A light gas (with 98.5% methane) was injected with a total injection rate of 150 MMSCF/day. This injection rate is assumed according to the capacity of ordinary gas processing and compression plants. Since the average reservoir pressure before gas injection was 3220 psia, the injection pressure must be higher, due to the frictional pressure drops in the well column and through perforations. We assume that the wells are completed in all layers. Additionally, we assume that the injectivity of all gas injector wells is such that each one can inject 50 MMSCF/day gas. The total production rate for all 16 wells was assumed to be maximum 120000 STB/day, i.e., 7500 STB/day per well. Three gas injector wells were assumed in any case in different configurations. The simulation model was run with the specified conditions (3 gas injection wells and 16 oil production wells) and gas injection scenario was assumed to last 30 years. 8 At the end of 30 years of gas injection scenario, the field will produce 7.532×10 STB oil and 10 8.72×10 SCF of associated gas. Based on the estimated initial oil in place of 2.8 MMMSTB, the ultimate recovery factor will be approximately 27%.

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

2.2 Water Injection Scenarios In case of water injection, some edge wells were set as water injectors and crestal wells were put on production. Unfortunately, there are a few edge wells that can be good candidates for water injection into aquifer or waterflooding in upper layers. We assumed that there is a water treatment plant with a capacity of at least 24000 STB/day for chemical treatment of seawater salts and compatibility purposes. We ignore the formation damage of probable incompatibility of injection water with formation water. Therefore, all injection wells are assumed to run with constant injectivity. Three water injection wells are planned to inject 8000 STB/day per well. We assume that the wells are completed in all layers. The total production rate for all 16 wells was assumed to be maximum 90000 STB/day, i.e., 5625 STB/day per well. The water injection scenario was let to last to continue for 30 years. At the end of 30 years of water injection scenario, the field will produce 8 7 6.93×10 STB oil and 8.0×10 SCF of associated gas. Based on the estimated initial oil in place of 2.8 MMMSTB, the ultimate recovery factor will be 24.7%. 3. Results and Discussion In this section the best cases of gas injection and water flooding are compared. Figures 1 to 7 compare oil production rate, total oil produced, water production rate, total water produced, gas production rate, total gas produced, gas-oil ratio, water cut, and average field pressures of best water injection and gas injection cases. Table 2 lists a comparison of produced oil and recovery factor for all cases. In Figure 1, oil production rates of waterflooding and gas injection are compared. In gas injection scenarios, field produces the oil with a rate of 120,000 STB/day, while in waterflooding scenario; it produces 90,000 STB/day. The starting rate in gas injection is higher, therefore the plateau is very short and production rate declines. However, the decline rate in gas injection is slower than waterflooding. Almost in all times, the total oil flow rate of the field is higher in case of gas injection. As a result, the cumulative oil production is higher when gas injection is applied (Figure 2). Figure 3 shows gas production rate for two scenarios. Since the oil flow rate is higher in case of gas injection, the same trend is expected for gas production rate. During gas injection, if the gas breakthroughs the production wells, the flow rate of gas production will be much larger than rate of gas production in water flooding. However, in this case gas breakthrough has not been occurred. Surprisingly, the rate of water production is higher in case of gas injection (Figure 4). This may be due to possible water coning as a result of higher flow rate and higher pressure drop in the near wellbore region. Natural water influx from the reservoir is a major drive force in Soroosh field. Figure 5 compares the gas-oil ratio for two cases. This confirms that the gas production in case of gas injection scenario is exactly the associated gas which is produced with oil. In other words, gas has not been breakthrough in gas injection scenario. Figure 6 illustrates the water cut of produced liquid in two cases. The difference between the two water cut curves is just 2-5%. This fact shows that higher production rate of water in gas injection case is due to the higher rate of oil production. Additionally, since the water cut does not increase sharply in case of waterflooding, one can conclude that water has not breakthrough in waterflooding scenario.

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

Finally, Figure 7 displays average reservoir pressure is in two cases. In gas injection scenario, the pressure decreases more rapidly than in water flooding. After 2800 days from the start of water and/or gas injection, the pressure tends to increase slightly in case of water injection and then decreases slowly at the end.

Conclusions Natural production of oil by depletion and water drive from aquifer will result in very low ultimate recovery factor due to relatively heavy to heavy oil in Soroosh Burgan-B reservoir. The ultimate recovery factor will be around 6.5% after a production period of 30 years. The variation in oil viscosity in Burgan-B reservoir is very large, ranging from 15 to 800 cP. Almost half of the initial reserve of this reservoir belongs to the bottom layer which bears high viscosity heavy oil. Conventional production drives such as rock and fluid expansion, water influx, and solution gas drive are not efficient in recovering this heavy oil. Therefore special enhanced oil recovery methods should be applied in Soroosh field. Waterflooding can be efficient just for upper high permeability layers which contain lighter oil. From simulation runs, it was found that water flooding can increase recovery factor to 24.7% over a period of 30 years. With a starting oil rate of 90,000 STB/day, the plateau remains longer than gas injection scenario and lower pressure drop occurs in the reservoir, but the decline rate is slightly larger than that of gas injection. From the gas injection simulation runs, it was found that immiscible gas injection can increase ultimate recovery to 27% which is higher than that of waterflooding. The decline rate of production during gas injection was slower than that of waterflooding, which results in higher oil flow rate and ultimate recovery. In both cases, the injected fluid did not breakthrough the reservoir and was not produced in wells. This shows that both cases must be investigated in a longer period of time to examine the final effect of injection/production scenarios. In addition, both scenarios may be considered as pressure maintenance, secondary oil recovery methods. The pressure drop was slower after fluid injection and breakthrough did not occurred. There are two vertical shale barriers which divide the reservoir into three parts and isolate three parts. These barriers are a deficiency for any enhanced oil recovery process. They also necessitate larger number of wells to deplete the reservoir.

References 1- Dyer, S.B., and FarouqAli, S.M., 1990, Linear Model Studies of the Immiscible Carbon Dioxide WAG Process for the Recovery of Heavy Oils: SPE Latin American Petroleum Engineering Conference, Rio de Janeiro

2- Hatzignatiou, D.G., and Lu, Y., 1994, Feasibility Study of Co2 Immiscible Displacement Process in Heavy Oil Reservoirs: 45th Annual Technical Meeting organized by The Petroleum Society co- sponsored by AOSTRA, Calgary, AB. 3- Rojas, G.A., 1985, Scaled Model Studies of Immiscible Carbon Dioxide Displacement of Heavy Oil: Ph.D. Thesis, University of Alberta

4- Rojas, G.A. and FarouqAli, S.M., 1988, Dynamics of Subcritical CO2/Brine Floods for Heavy Oil Recovery: SPERE, pages: 35-44

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

5- Stalkup, F.I., 1983, Miscible Displacement: SPE Monograph Series, Society of Petroleum Engineers, Dallas 6- Szasz, S. E. and Thomas, G.W., 1965: Principles of Heavy oil Recovery, JCPT 65-04-03 7- Wang, W. D., 1988, Cold Production and Wormhole Propagation in Poorly Consolidated Reservoirs: Petroleum Society of CIM Table 1 STOIIP Distribution per Depth Interval % of (TVD m) Oil density (°API) Viscosity (cP) STOIIP Top - 2150 21-20 14-18 5% 2150 - 2160 20-18 18-27 4% 2160 - 2170 18-16.5 27-35 5% 2170 - 2180 16.5-15.5 35-46 5% 2180 - 2190 15.5-14.7 46-68 6% 2190 - 2200 14.7-14 68-95 6% 2200 - 2210 14-13 95-172 7% 2210 - 2220 13-12 172-307 8% 2220 - 2230 12-10 307-859 9% 2230 - WOC <10 >859 46%

Table 2 Comparison between Different Scenarios

Total Oil Production Recovery Factor Case (MMSTB) (%)

Before Development 86 3.1

Natural Production 182 6.5

Water Injection 693 24.7

Gas Injection 753 27

Fig. 1 Comparison of Oil Production Rate Fig. 2 Comparison of Total Oil Production for Two Scenarios for Two Scenarios

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

Fig. 3 Comparison of Gas Production Rate Fig. 4 Comparison of Water Production Rate for Two Scenarios for Two Scenarios

Fig. 5 Comparison of Production GOR Fig. 6 Comparison of Production Water for Two Scenarios Cut for Two Scenarios

Fig. 7 Comparison of Average Field Pressure for Two Scenarios

2018

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

Facies analysis and depositional environments of the Qom Formation in Vieh section, south of Saveh

Mahnoush Mohammadi1*, Nader Kohansal Ghadimvand2, Seyed Hamid Vaziri2, Masood Mosavian3

1*- university student In sedimentology and Petrology of Sedimentary Rocks of Azad university- NorthTehran branch )[email protected] (09125359220), 2- Board of member- geology department of Azad university- NorthTehran branch. And 3- Superior export of Exploration Directorate- surface geology office.

Abstract The Qom Formation (Oligo- Miocene) is the most important hydrocarbon source in central Iran. The Qom Formation stands between the Lower Red and Upper Red Formations with unconformity. The Qom Formation in Vieh section in south of Saveh was studied for stratigraphic survey, facies analysis and environmental interpretation. The Qom Formation has 220 meter of thickness. In the studied area, it mainly consists of medium-thick layered to massive limestone, marl and sandstone. The Assessment of thin sections in Vieh section led to recognition of 4 facies groups related to coast, lagoon, barrier and open marine. Lagoonal facies consist of packstone and wackestone textures. Barrier facies were formed boundestone and bioclastic grainstone and open marine facies have turbidities and talus characteristics.

Keyword: Facies, Sedimentary environments, Qom Formation, Oligomiocene, Vieh and saveh.

1- Introduction The age of the Qom Formation generally has been determined from early Oligocene till middle Miocene and it is equivalent to the Asmari Formation. In the coarse of oil exploration of the Qom Formation in the south part of the Qom town, six lithological units (a-f) has been recognized (Ganser, 1955; Soder and Furrer, 1955). The studied area located in the south part of Saveh province (Fig. 1). The purpose of this study is to investigate facies and to recognize sedimentary environment of the Qom Formation in Vieh region. After field study one stratigraphy section has been chosen and sampling it. Thin sections have been provided from the samples.

2- facies description: Microschopic properties of thin section lead into recognition of 11 microfacies in form of 2 groups of carbonate & terrigeneous facies. A: The group of beach facies Beach facies of Qom formation in Vieh area are sandstone. Among most important facies of this group the fallowing samples can be pointed out; A1) Fine to medium sandstone: calcite cemented submature litharenite Quartz is the Main components in this facies. Quartz with parallel extinction and undulatery extinction exists in this facies. Frequency of Qrtuz and Plagioclase are worthless. Also chert, Siltstone, calcareous rock fragments and shale are exist (Fig 3, A).

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

A2) sandy limestone-calcareous sandstone Some times in some samples quantity of terrigenous and carbonate components are to the extent that nomenclature and their segregation to terrigenous or carbonate facies is impossible. Elements constitute mainly are red algae, benthic foraminifera, echinoderma, bryozoa, quartz (Fig 3, B).

B:The group of lagoonal facies In the studied area lagoonal facies can be divided to: B1) Gastropoda benthic Foraminifera Bioclast Packstone The most important skeletal allochems in this facies are benthic foraminifera, gastropoda, neoalveolina, echinoderma, red algae and bryozoa. These grains settle in the micritic background which recrystalizate to microspar (Fig 3, C). B2) Benthic foraminifera bioclast wackestone Major elements in this facies are benthic foraminifera, echinoderm, red algae and peloid (fig 3, D). B3) Red algal bioclast packstone Red algae are the major allochems in this facies. Among other allochems can be mentioned to echinoderma and benthic foraminifera with slightly frequency (Fig 3, E).

C: The group of barrier facies: Barrier facies in the studied area are boundstonic reef and bioclastic barrier that can be classified into: C1) Coralgal boundstone: Coral and algae are the major components in reefal facies and according to Emberry and Klovan (1971), framestone and bindstone rocks are recognized in this facies (Fig 3, F). C2) Benthic foraminifera bryozoa bioclast grainstone Components of this facies are bryozoa, red algae, echinoderma, benthic foraminifera, oyster, gastropod and interaclast. C3) Sandy echinoderm benthic foraminifera bioclast grainstone Components of this facies are benthic foraminifera, echinoderm, Also micritic ooids and intraclast exists in these facies, frequency of terrigeneous particles such as quartz is high. (Fig 3, G). C4) Intraclast Pelecypoda Algal Bioclast Packstone Major components in this facies are red algal, oysters, bryozoa, echinoderms, sorithida and benthic foraminifera. Large intraclast exist in this facies (Fig 3, H)

D: the group of open marine facies Facies of open marine can be sub divided into: D1) Echinoderm coralgal bioclast packstone Major components in these facies formed reefs most of the times, these organisms to consist of red algae; allochtonous corals, echinoderm and brozoa. D2) Benthic Foraminifera Bryozoa Packstone major elements in this facies firstly is bryozoa. Other important element is large benthic foraminifera. Spaces between these allochems filled by matrix which shows low energy environment (Fig 3, I).

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

D3) Benthic/ planktonic foraminifera bioclast wackestone In this facies both type of benthic and planktonic foraminifers. Echinoderm and red algae with slightly frequency are other allochems in this facies (Fig 3, J). D4) shale/ marl This facies has green looking grey color and very thin lamination; mostly it has periodicity with carbonate facies.

Conclusion: Qom Formation in Vieh section includes terrigeneus-carbonate deposition that started by beach terrigeneus facies and ended by carbonate facies. Microscopic surveys due to recognition 4 group facies: A-beach, B-lagoon, C- barrier and D- open marine (Fig, 2). Beach facies are sandstone but in some thin sections terrigeneous and carbonate components mixed together. Lagoonal facies have wackestone and packstone textures. Coral- algae boundstone and open marine facies have talus and turbidities characteristics most probably facies of Qom Formation in Vieh section was shaped in a carbonate platform type Rimmed shelf.

Fig 1- geological position and connection roadway to the study area

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

Fig 2- stratigraphic and facies column of the Qom Formation in Vieh section associated with depth variation of sedimentary environments

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

A B ش ش ش ش

C D ش ش ش ش

E F ش ش ش ش 1 : 1 , 0 0 0 , G H 0 ش ش 0 ش ش 0

I J ش ش ش ش

Fig3) A- Fine to medium sandstone: calcite cemented sub mature litharenite. B- Sandy limestone- calcareous sandstone with quartz, benthic foraminifera, red algae and bryozoa. C- geopetal fabric in the bryozoa chamber (on the lower side in the left hand corner) in facies of gastropoda benthic foraminifera bioclast packstone. D- benthic foraminifera bioclast wackestone. E- Red algae bioclast packstone include geopetal fabric among train of algae. F- Boundestone composed from coral and algae, neomorphism caused the bursting of some parts of coral structures. G- Concave-convex contact between milliolid because of weight of tops beds in facies of sandy echinoderm benthic foraminifera bioclast grainstone. H- Ooid intraclast in facies of pelecypood algal bioclast packstone. I- Benthic foraminifera bryozoa packstone, hematization on the lower part. J- Benthic/ planktonic foraminifera bioclast wackestone

2023

The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 Matrix Acid Stimulation

Maryam Dehghani

Petroleum Engineer – Iran [email protected]

Abstract Matrix acid stimulation is a relatively simple technique that is one of the most cost-effective methods to enhance well productivity and improve hydrocarbon recovery. Carbonate acidizing is usually performed with HCl except in situations where temperatures are very high and corrosion is an issue. Acids attack steel to produce solutions of iron salts while generating hydrogen gas. Over the years, many different acidizing systems have been developed for specific applications.

Introduction Matrix acid stimulation is a relatively simple technique that is one of the most cost-effective methods to enhance well productivity and improve hydrocarbon recovery. The science of acidizing originated more than 100 years ago when Herman Frasch of Standard Oil patented the use of hydrochloric acid (HCl) to stimulate carbonate formations. One of his colleagues patented the use of sulphuric acid for the same purpose. After a flurry of activity, neither technique was applied on a widespread basis during the next 30 years. The effect of the treatment on production was positive, if not spectacular, and provided the impetus to perform more treatments. Some of the later treatments produced excellent results, and news of the technique quickly spread. In the same decade, attempts were made to improve production from sandstone reservoirs by injecting mixtures of HCl and hydrofluoric (HF) acid. These early treatments were not particularly successful, and the HCl/HF mixtures were relegated to only occasional use in wells with drilling mud damage. It was not until the 1960s that treatments containing HF again saw widespread use in well remediation when studies on chemical interactions of HF with typical sandstone formation materials and guidelines for treatment optimization were published. Despite the elimination of much of the mystery surrounding the use of HF, acidizing sandstone formation remained a hit-or-miss enterprise. It was very successful in some areas and totally disastrous in others.

Chemistry In the early days of acidizing, wellsite quality control was almost nonexistent, and little attention was paid to such variables as acid strength. Improved understanding initially came from empirical observations in the field followed by extensive research and development work carried out by thousands of scientists and engineers. Core flow studies, geological and mineralogical investigations, reaction kinetics, physicochemical modeling of the propagating reaction front, solubility testing, and reaction products analysis are some of the many aspects of matrix acidizing that have been investigated. Sophisticated modern-day analytical techniques, coupled with computer modeling, have allowed detailed examination of the acidizing process to provide a better understanding of potential pitfalls and how to avoid them.

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

Acid System Design Carbonate acidizing is usually performed with HCl except in situations where temperatures are very high and corrosion is an issue. In such situations, organic acids like acetic or formic acids are used because they are much less aggressive. Occasionally, it may be beneficial to retard acid formulas, slowing their reaction rate to allow deeper penetration of live acid or preferential creation of large wormholes through any near-wellbore damage. Selection of an appropriate acid design for sandstone formations is a more esoteric matter. Part of this problem stems from the complex and heterogeneous nature of most sandstone matrices. Interactions between the many different mineral species and the injected acid depend not only on the chemical composition of both but also on temperature, pressure, surface morphology, pore size distribution, and pore-fluid composition. Over the years, many different acidizing systems have been developed for specific applications. In general, the three principal drivers for these developments have been (1) the desire to retard the acid/mineral reactions, thereby achieving greater penetration; (2) the desire to make the acid less aggressive to tubulars, wellheads, and screens; and (3) the desire to avoid undesirable reactions that could result in formation damage. Some approaches used to retard the acid have included buffered HF systems or organic systems, fluoroboric acid, and mixtures of esters and fluorides to generate HF in situ by thermal hydrolysis. Other, more exotic efforts have included the use of hexafluorophosphoric acid or hexafluorotitanic acid. For carbonate acidizing, mixtures of esters with enzymes have been used to generate organic acids in situ. In general, systems that generate acid in situ or that use organic acid blends also address the problem of corrosion, but such systems may still cause corrosion problems on flowback if they contain no inhibitors. Mitigating undesirable reactions or their byproducts has spawned many proprietary formulas as well as changing some of the application guidelines used in matrix acidizing. The old generic acids consist of mixtures of HCl and HF acid, known in the industry as mud acid. Traditionally, the HCl/HF ratio was 4:1. However, it has been suggested that it may be necessary to increase this ratio to as much as 9:1. The rationale for these relatively high HCl/HF ratios is that dissolution of clays by HF mixtures produces many secondary reaction products that can reprecipitate in the formation and cause damage. These damaging reaction products are slightly more soluble if the pH is kept low throughout the treatment and during flowback. New acid systems have been developed that do not reduce the useful life of well tubulars, and excess HCl is no longer required to reduce secondary precipitates.

Corrosion Inhibitors Acids attack steel to produce solutions of iron salts while generating hydrogen gas. Depending on the steel metallurgy, type of acid (mineral or organic), acid strength, and temperature, the reaction may be more or less vigorous. This attack can lead to removal of a substantial amount of metal mass, potentially shortening the lifespan of well tubulars. It was the discovery of an effective corrosion inhibitor that sparked the widespread application of acidizing in the 1930s. That first inhibitor was based on arsenic, and, while efficient, its use was discontinued because of concerns over toxicity and the environment. A variety of organic inhibitors superseded the early arsenic compounds. The majority of these are based on acetylenic alcohols, like octynol and propargyl alcohol, highly reactive molecules containing

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 a carbon-carbon triple bond. The ability of these materials to protect steel is dependent on the proper dispersion of the hydrophobic alcohol in the acid because the protection mechanism involves creation of an inhibitory film on the metal surface. Environmental legislation has forced a re-evaluation of many corrosion inhibitors. There is some indication that the most effective way to acidize high-temperature wells is to use organic acids like formic and acetic instead of mineral acids because they are much easier to inhibit and are relatively cost competitive and biodegradable.

Iron Control Agents Iron is plentiful in any oilfield operation and is perhaps the most underestimated problem in acidizing. In general, clean steel dissolves to produce ferrous ions, but these can be converted to the problematic ferric ion by dissolved oxygen. Several iron reaction products can precipitate from acid as it spends and the pH rises. The most likely to precipitate is ferric hydroxide, which forms a gelatinous plugging precipitate when the acid pH rises. The most common chemical methods used to address the issue of iron precipitation include chelation/sequestration and reduction. Sometimes, combinations of different reducing agents are used to provide iron control while minimizing any risk of unwanted byproducts.

Clay Stabilizers Sandstone formations are heterogeneous with quartz as the primary skeletal mineral and various carbonates, clays, or feldspars acting to cement the sand grains together. In addition, clay minerals may be suspended in the pore filling fluid or may line the pore spaces. These clays can react by ion exchange or partial dissolution when contacted by injected fluids. Often, this results in the disaggregation, disintegration, or swelling of the clay and can plug the pore spaces and pore throats. Many acidizing formulas contain clay stabilizers to mitigate the problem. The simplest clay stabilizers are salts such as ammonium and potassium chloride; however, potassium chloride cannot be used when HF is used because of the risk of secondary precipitates like potassium fluorosilicate. It is much more common to incorporate any one of the several synthetic materials that prevent clay swelling in the treating fluids. These materials are usually cationic, like quaternary amines or polymers with similar active groups. Other materials have been used to prevent the migration of mobile clays or silica fines through the matrix because these can cause problems if they accumulate in the near wellbore. One approach has been to modify the acidizing system by replacing simple HF with fluoroboric acid, which is slowly hydrolyzed into HF, reducing the reaction rate of HF and helping to fuse clay platelets together.

Surfactants Surfactants encompass a very diverse group of chemicals including foaming agents, water- wetting agents, oil-wetting agents, emulsifiers, demulsifiers, and antisludge agents. All these agents have effects on surface and/or interfacial tension. Water-wetting surfactants lower the surface tension of aqueous fluids to improve the ability of the treating fluid to penetrate small pores and to react with the matrix constituents. Surfactants also improve the recovery of these

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 same fluids after the treatment. It is a widely accepted practice to include water-wetting surfactants in almost all matrix acid treatments. Demulsifiers and nonemulsifiers are designed to prevent or facilitate the breakup of the emulsions that tend to form between crude oil and live or spent acid fluids. Such emulsions can be very viscous, even quasisolid, and may plug the pores of the treated matrix.

Diverting Agents A certain volume of acid is allowed to flow into and remediate the higher permeability intervals, and then, the flow is diverted to lower permeability zones. The most common materials used to divert the acid are particulates that are insoluble in acid, but soluble in hydrocarbons for easy cleanup. Such agents include benzoic acid, naphthalene, oil-soluble resin, gilsonite, and wax beads. Other systems have included polymers that crosslink as pH or calcium ion level rises. Foaming agents are widely used in acidizing treatments to provide diversion. Another diverting technique is to use some selective isolation tool such as a straddle packer or sets of opposing cups to bracket the interval exposed to the acidizing fluid. Recently, jetting techniques have been used to improve placement selectivity of stimulation fluids in gravel- packed completions.

Conclusion 1. Matrix acidizing, with the appropriate systems in correctly identified candidate wells, is the most cost-effective way to enhance oil production in sandstone and carbonate reservoirs. 2. Increased understanding of the chemistry and physics of the acidizing process as well as improvements in wellsite implementation have resulted in better acidizing success. 3. Use of computer software that includes all known rules and guidelines for sandstone acidizing can greatly improve the success ratio by eliminating inappropriate designs and standardizing treatments. 4. New acid systems with improved performance were developed specifically to address many of the problems inherent in sandstone acidizing.

Acknowledgement The author wishes to express his sincere thanks and gratitude to technical manager of Aghajari Oil and Gas Production Company (Aj.O.G.P.C). I also wish to thank the Heads of Research and Technology Department in National Iranian South Oil Company (N.I.S.O.C) and Heads of Research and Technology Department in National Iranian Oil Company (N.I.O.C) for their helps and encouragements in connection with this study.

References 1. D.R Mc Cord & Assoc. , " Reservoir Engineering and Geological Study and Analysis for Fracture Operation " , vol. 2 , 1974 . 2 . D.R.Mc Cord & Assoc., " Fracture Study of Asmari Reservoir " 1975 .

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3 . Tiratsoo, E.N. , " Oil Field of The World ", Gulf Publishing Company, 1986 12 . " Petroleum Measurement Tables " , ASTM , 1990 . 13 . G.D.HOBSON ," Modern Petroleum Technology ", John Willey & Sons , 1994 14 . D.Nathan Meehan & Ericl .Vogel , " Reservoir Engineering Manual ", PennWell , 1988 . 15 . Fred I. Stalkup JR , " Miscible Displacement " , Society of Petroleum Engineers , 1998 . 16 . Pettijohn Potter , " Sand and Sandstone " , Springer Verlag , 1996 .

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Investigation of metamorphic zonation and isogrades of Garnet rocks in Hamadan area

Zahra Hossein mirzaei1*, Ali Asghar Sepahi1, Farhad Aliani1, Zohreh Hossein mirzaei2

Corresponding author: 1GeologicalSurveyofHamadan, Iran

2GeologicalSurveyofIslamicAzadUniversity, Khorasgan branch, Iran . E-mail address: [email protected]

Abstract The study area is a part of the Sanandaj- Sirjan metamorphic belt. We can divide Hamadan metamorphic rocks in three groups: regional metamorphic rocks, contact metamorphic rocks and migmatites. In this area we can’t completely divide zonation of contact and regional metamorphic. In some places that contact metamorphic has influenced to low degree regional metamorphic rocks, contact metamorphic zonations are clearly appear, but when contact and regional metamorphic have a same degree or regional metamorphic has high degree than contact metamorphic, we can’t distinguish them easily. In Hamadan area regional metamorphic zones are Chlorite± Biotite zone (we haven’t garnet rocks in this zone), Biotite± Garnet zone (divided in two sub zone, Biotite and Garnet zone), Andalusite zone, Staurolite zone, Staurolite± Andalusite zone, Sillimanite- Muscovite zone and Sillimanite- Potassium feldspar± Cordierite zone, also contact metamorphic zones are Cordierite zone and Cordierite- Potassium feldspar zone.

1. Introduction Garnet crystallizes in cubic system and mostly in dodecahedron (rhomb-dodecahedron) and trapezohedron (tetragon-trioctahedron) crystal forms. General chemical formula of this 2+ 2+ 2+ 2+ mineral is: R3R‘2(SiO4)3, which bivaliant cations (i.e. Mg , Fe , Mn , Ca ) lie in R site and trivaliant cations (i.e. Al3+, Cr3+, Fe3+) in R‘ site. Commonly, more than one cation lies in R and R‘ sites and therefore garnet crystals give rise to isomorphous (solid solution) series of 3+ 2+ 2+ 2+ minerals. If Al is located in R‘ site, the pyralspite group [( Fe ,Mg ,Mn )3 Al2(SiO4)3] 2+ 2+ with almandine [(Fe )3 Al2 (SiO4)3], pyrope [(Mg )3Al2 (SiO4)3] and spessartine 2+ 2+ [(Mn )3Al2(SiO4)3] end members will form. If Ca is located in R site, the ugrandite group 2+ 3+ 3+ 3+ [(Ca )3(Al ,Fe ,Cr )2(SiO4)3] with grossularite [Ca3Al2(SiO4)3], andradite 3+ 3+ [Ca3(Fe )2(SiO4)3] and uvarovite [Ca3(Cr )2(SiO4)3] end members will form. Some other cations may also be emplaced in R and R‘ sites (Locock. 2008). The garnet minerals chemistry in the study area are rich in almandine.

2. Geological Setting The study area is a part of the Sanandaj-Sirjan metamorphic belt. The Alvand plutonic complex is the most important plutonic body that regional and contact metamorphic rocks with low to high grade are located around it. The metamorphic sequence comprises pelitic, psammitic, basic, calc-pelitic and calc-silicate rocks. Pelitic rocks are the most abundant lithologies. Pelitic sequence is mostly made up of slates, phillites, micaschists, garnet schists, garnet andalusite (± sillimanite, ± kyanite) schists, garnet staurolite schists, mica hornfelses, garnet hornfelses, garnet andalusite (± fibrolite) hornfelses, cordierite (± andalusite)

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 hornfelses, cordierite K-feldspar hornfelses and sillimanite K-feldspar hornfelses. Major plutonic rocks of this area are granitoids, diorites and gabbroids, which intruded by aplo- pegmatitic and silicic veins (figure 1).

3. Metamorphic zonation and isogrades of Garnet rocks in study area In this area we can‘t completely divide zonation of contact and regional metamorphic. In some places that contact metamorphic has influenced to low degree regional metamorphic rocks, contact metamorphic zonations are clearly appear, but when contact and regional metamorphic have a same degree or regional metamorphic has high degree than contact metamorphic, we can‘t distinguish them easily. The metamorphic reaction and thermobarometric studies of metamorphic rocks have shown that garnet mica schist forming at 4.3 ±0.5 Kbar and 568-586 ºC and garnet hornfelses at 2.5 ±0.1 Kbar and 539-569 ºC (Sepahi et al. 2004)

3-1- Regional metamorphic rocks Low grade rocks (Chl zone): the lowest-grade rocks are very fine grained black,green or cream colored slates and phyllites, interlayered with carbonate rocks and quartzites. Slates contain Quart, Sericite, Chlorite, Graphite, Iron oxides. Phyllites contain Quart, Muscovite, Chlorite, Plagioclase, +/-Garnet, +/- Biotite, as well as accessory Tourmaline, Calcite and Iron oxides. Samples of metamorphic reaction that have shown in this zone are:

Kln + 2Qtz Prl + H2O (Thompson. 1970) 2Ms + 6Qtz + 2H+ 3Prl + 2K (Frey. 1978) Biotite and garnet zone: These rocks are medium to coarse grained and their common texture is lepidoporphyroblastic with a usual crenulation cleavage. This zone divided in two sub zone, biotite and garnet zone. They are composed of Quartz, Biotite, Garnet (up to 10 mm in size), Muscovite, Chlorite, with accessory Plagioclase, Graphite, Tourmaline, Apatite, Calcite and Iron oxides (Fig 2). Common porphyroblasts are Garnet, Muscovite and Chlorite. Garnet crystals have complex relationship to deformation, i.e. they are pre-, syn- and post-tectonic. The metamorphic reaction and thermobarometric studies of metamorphic rocks have shown that garnet mica schist forming at 4.3 ±0.5 Kbar and 568-586 ºC (Sepahi et al. 2004).

Chl + Ms Grt + Bt + Qtz + H2O (Whitney et al. 1996) 2Chl + 4Qtz 3Grt + 8H2O (Kretz. 1994) Chiastolite zone: These rocks are medium to coarsed grained with a common lepidoporphroblastic texture. Their common minerals are Quartz, Biotite, Andalusite (up to 20 cm length), Garnet, Muscovite and minor Graphite, Chlorite, Plagioclase, Tourmaline, Apatite, Sillimanite and Iron oxides (Fig 3).

Grt + Ms + Qtz And + Bt + H2O (Yang and Pattison. 2006) Staurolite zone: These rocks are composed of Quartz, Staurolite, Garnet, Biotite, Muscovite, Chlorite, Plagioclase, Graphite and Tourmaline (Fig 4). Their common texture is lepidoporphyroblastic with porphyroblasts of garnet, staurolite (up to 15 cm in legnth).

Grt + Chl +Ms + Qtz St + Bt + H2O (Yang and Pattison. 2006) Sillimanite muscovite zone: Sillimanite andalusite schists contain Quartz, Sillimanite .(andalusite), Biotite, Muscovite, Garnet, Plagioclase and Opaque minerals (Fig 5ֱ±)

Grt + Ms + Qtz Sil + Bt + H2O (Yang and Pattison. 2006)

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Sillimanite- potassium feldspar zone: High grade schists and Migmatites are in this zone. The high grade schists in the regional metamorphic sequence contain Sillimanite, Quartz, Biotite, Muscovite, Garnet, Plagioclase, Potassium feldspar, ±Andalusite,±Kyanite, ±Staurolite (Fig 6). Migmatites are a sequence of metatexite-diatexite rocks with various structures such as stromatic, schollen, schlieric and massive. The melanosome mineralogy of the most of the metatexites is very similar to high grade Garnet sillimanite (± andalusite and kyanite) schists but Cordierite-bearing interlayers occur, too (Fig 7). Leucosome of migmatites have granoblastic texture and contain Quartz, Plagioclase, Muscovite and ±Garnet. Bt + Ab + Sil + Qtz Grt + Kfs + L (Norlander et al. 2002)

3-2- Contact metamorphic rocks Protoliths of the contact metamorphic rocks are similar to those in the regional metamorphic sequence and include abundant metapelitic rocks. Two metamorphic zones are widespread around plutonic bodies.

Cordierite zone: The major rock types in this zone are Cordierite hornfelses. This rocks have porphrogranoblastic texture that containing Quartz, Biotite, Muscovite,contact Cordierite (± andalusite), Plagioclase, Garnet, Tourmaline and Opaque minerals (Fig 8). garnet hornfelses forming at 2.5 ±0.1 Kbar and 539-569 ºC (Sepahi et al. 2004)

Chl + H2O Grt + H2O (Kretz. 1994) Cordierite potassium feldspar zone: The typical mineral assemblage of these rock is Quartz, contact Cordierite (Crd2), orthoclase, Biotite, minor Plagioclase, Garnet and Opaque minerals (Fig 9).

Bt + Sil (  And) + Qtz Crd + Kfs + H2O (Kretz. 1994) Minerals assemblage in metamorphic zonation are shown in table 1.

4. Conclusion We can divide Hamadan metamorphic rocks in three groups: regional metamorphic rocks, contact metamorphic rocks and migmatites. In this area regional metamorphic zones are Chlorite± Biotite zone, Biotite± Garnet zone, Andalusite zone, Staurolite zone, Staurolite± Andalusite zone, Sillimanite- Muscovite zone and Sillimanite- Potassium feldspar± Cordierite zone, also contact metamorphic zones are Cordierite zone and Cordierite- Potassium feldspar zone.

References: 1-Frey, M., 1978, Progressive Low grade metamorphism of a Black Shale Formation, Central Swiss Alps, with special reference to pyrophyllite and margarite bearing assemblages. J. Petrol, 19, 95- 135. 2-Kretz, R., 1994, Metamorphic crystallization. John Wiley and Sons, 507. 3-Locock, A., 2008, An Excel spreadsheet to recast analyses of garnet end-member componets, and a synopsis of the crystal chemistry of natural silicate garnets. Computers and Geosciences. V, 34, 1769-1780.

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4-Norlander, B.H., Whitney, D.L., Teyssier, C. and Vanderhaeghe, O., 2002, Partial melting and decompression of the Thor-Odin Dome, Shuswap metamorphic core complex. Canada. Cord. Lithos, 61, 103–125. 5-Sepahi, A. A., 2007, A detailed study of morphology and chemistry of garnet crystals with suggestion of new subdivisions: data from pelitic schists, hornfelses and aplites of hamadan region. Iran. J. Sci. Tehnology, V. 31, No. A3. 6-Sepahi, A.A., 2008, Typology and petrogenesis of granitic rocks in the Sanandaj-Sirjan metamorphic belt, Iran: With emphasis on the Alvand plutonic complex. N. Jb. Geol. Palaton. Abn, 247, 295-312. 7-Sepahi, A. A., Whitney D. L. and Baharifar A. A., 2004, Petrogenesis of andalusite-kyanite- sillimanite veins and their host rocks, Sanandaj-Sirjan metamorphic belt, Hamadan, Iran. J. Met. Geol, 22, 119-134. 8-Thompson, A.B., 1970, A note on the kaolinite- pyrophyllite equilibrium. Am. J. Sci, 268, 454-458. 9-Whitney, D.L., Mechum, T.A. and Dilek, Y.R., 1996, Progressive metamorphism of pelitic rocks from protolith to granulite facies. Dutchess County, New York, USA: Constraints on the timing of fluid infiltration during regional metamorphism. J. Met. Geol, 74, 163-181. 10-Yang, P. and Pattison, D., 2006, Genesis of monazite and Y zoning in garnet from the Black Hills, South Dakota. J. Lithos, 88, 233-253. Table 1: minerals assemblage in metamorphic zonation. Sillimanite zone Staurolite zone Andalusite zone Garnet zone Biotite zone Chlorite zone Quartz ...... Chlorite ...... Biotite ...... Muscovite ...... Garnet ...... Andalusite ...... Staurolite ...... Kyanite ...... Sillimanite ......

Fig 1: Simplified zonation map of the Hamadan area (modified after Sepahi, 2008).

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Fig 2: Mineral assemblage in Garnet zone. Fig 3: Mineral assemblage in Chiastolite zone.

Fig 4: Mineral assemblage in Staurolite zone. Fig 5: Mineral assemblage in Sillimanite muscovite zone.

Fig 6: Mineral assemblage in Fig 7: Mineral assemblage in Cordierite zone. Sillimanite- potassium feldspar zone.

Fig 8: Mineral assemblage in Cordierite potassium feldspar zone.

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

Palaeoenvironment and Sedimentation Settings during Asselian – Sakmarian Reorganizations in Harzand area (North of Marand)

Mousa Bagheri

Corresponding author: Department of Geology, Urmia Campus, Islamic Azad University, Urmia, Iran. E-mail address: [email protected]

Abstract Several major transgressive cycles can be recognized within the Permian sequences in Northwest of Iran. The first transgression begins with conglomerate, microconglomerate, litharenite, sublitharenite and quartzarentie sandstone, siltstone, mudestone and shale with Asselian to Sakmarian age. This clastic sequence is lying with disconformity and hiatus on the older formations with a various ages. Outcrops of the Lower Permian (Dorud Formation) have been studied in Harzand area to determine their facies, sedimentary enviroments and their sequences. Continental and clastic deposits in the study area, having a thickness over 120m, are divided into three units on the basis of their vertical sequential changes and lithologic characteristics. On the basis of stratigraphic and sedimentologic features of the Lower Permian continental sequence, six facies and three sub facies were defined in the study basin. Siliclastic facies of the Dorud Formation are related to meandering river environment. The occurrence of reworked clasts in conglomerate and microconglomerate lag deposits, indicate that they were derived from the grains contained in blocks of floodplain deposits. This facies association is interpreted as fluvial channel deposits. Petrographically, the sandstone is formed of monocrystalline quartz grains which form more than 75% of the rock content (quartz arenite). The grains range in size from very fine to medium sands. Locally, ferruginous cement constitutes the major cement where the pores are completely plugged with iron-oxides. It is dominated by flat-bedding and planar cross-bedding with minor trough cross-bedding and ripple marks. This facies was deposited in a meandering fluvial system in channels with lateral accretion movements in which point bars formed. The sand bodies composed of planar and trough cross bedding and ripple cross-lamination are interpreted as low-sinuosity channel fill deposits. The most floodplain lithofacies in the study area is shale and silty mudstone, which exists in intervals up to 5 m thick and constitutes 30–40% of logged sections. The vertical arrangement of these facies types is indicative of repetitive, fining-upward cycles of fluvial origin. Each of these upward fining cycles is marked, from oldest to youngest, in the lithologs. In the present study, the sequence stratigraphic interpretation is based on analysis of the unconformities and other stratigraphic surfaces together with the macroscopic and petrographic studies of the enclosing sediments and their stratal geometry. The lowstand fluvial deposits marking the base of the Durod formation clastic facies are overlain by middle-upper Permian carbonate succession. Sequence stratigraphyic analysis indicate the presence of lowstand system tract in the Dorud Formation that are related to river environment. The lower and upper boundary of the sequence is a type 1 Unconformity.

Key words : Dorud Formation, facies, sequence stratigraphy, meandering river, lower Permian.

Introduction: In the vicinity of the town of Marand, in the Northwest of Iran, Cisuralian form a thick sequence of Durod Formation of predominantly siliciclastic deposits. During the Lower Permian, a meandering fluvial system developed on Gondwana continental crust adjacent to

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 the Iran Shield. Permian rocks are widely distributed in Northwest Iran, including Azarbaijan. The stratigraphical data are based on (Stepanov et al. 1969 [1] , Shabanian and Bagheri, 2008 [2], Asseroto , 1963 [3]). The Permian rocks can be divided into four lithostratigraphic units and including Dorud (Asselian-Sakmarian), Ruteh Formation (Kubergandian - Murgabian) Nesen Formation (Midian - early Dzhulfian) and Ali bashi Formation (Late Dzhulfian - Dorashamian) respectively. The Permian rocks underline nonconformitably by Pre-Permian intrusive rocks and overlain Paraconformably by Elika Formation of Early- Middle Triassic age. The Durod Formation is transgressively overlain by a carbonate sequence of the Ruteh Formation.

Geological and stratigraphic setting: The Early Permian deposits of in Harzand area (South of Julfa) include the Dorud Formation. Outcrops of Permian succession in the Harzand section have been studied to determine their facies and depositional environments. In the study area, the Dorud Formation (120 meters) consist of red sandstone, shale and conglomerate (Fig. 1). Field investigations and laboratory works show that this continental and clastic sediment was deposited in a meandric river. Because of absence of fossils of foreminifera, the age of the sequence can‘t be determined. For petrographic studies and microfacies controls over 105 samples from Harzand stratigraphic section spanning Lower Permian strata were taken in Marand and Julfa regions. Middle and Late Permian limestones are characterized by medium to thick bedded skeletal limestone that includes abundant skeletal organisms such as fusulinids, smaller foraminifers, bryozoans, rugose corals, echinoderms, thin-shelled bivalves, gastropods, ostracodes, and dasycladacean algae. he thickness of the wackstone-packstone horizons decrease upwards and is finally replaced by massive, reefoidal limestone in the upper portion of the Surmaq Formation and terminates with bioclastic and oolithic limestone and dolomites; it is overlain by marly limestone of Julfa Formation. The various carbonates rocks record major depositional sequences, and are a sedimentary expression of variations in the depositional environment.

Methods of study: Three stratigraphic sections of the Dorud Formation were measured at Harzand, North of Marand. Stratigraphic sections, measured at a centimeter scale, record grain-size variations, sedimentary structures, paleocurrent directions, and bedding geometries (Figs. 1 and 2). This study is based on field observations and laboratory analysis of thin sections. Oriented specimens, cut perpendicular to bedding (along a growth direction), were then prepared for making thin sections. The lithological terminology of Folk , (1964) [4] and Tucker, (2001) [5] was used.

Sedimentation Settings: The lower Permian (Dorud formation) Reorganizations has a mean thickness of 120 m. A 10m thick basal quartzose conglomerate overlies the Permian unconformity. Planar–tabular cross-bedded sandstones make up most of the unit. The sandstones are fine to medium grained quartzarenites and sublitharenites arranged in 20m thick bodies formed by cross-

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 bedding sets defined by internal erosion or reactivation surfaces. The palaeocurrent distributions show a constant N trend. Detailed petrographic investigations led to the recognition of several microfacies which contain four environmental belts, including channel, point bar and floodplain. Obtained data from interpretation of these facies suggest that clastic sediments in Dorud Formation were deposited in a meandering river setting.

Fig. 1. A: Index map showing the location of Marand, Julfa and Harzand section. B: Paleogeographic map showing the supposed locations of Julfa, Gk- 1 core and Idrijca Valley sections. The map is modified from (Scotese, 1997 [6]). C: Lithostratigraphy and Stratigraphic column of the Asselian–Sakmarian sequence in the study area.

The Asselian–Sakmarian succession comprises six facies and three sub facies. Fluvial Channel facies association is made up of several, 15 to 45 cm thick conglomerate and microconglomerate with sandstone bodies. The occurrence of reworked clasts in conglomerate and microconglomerate lag deposits, indicate that they were derived from the grains contained in blocks of floodplain deposits. This facies association is interpreted as fluvial channel deposits. A >2-m-thick basal quartzose conglomerate overlies the Permian unconformity. Floodplain lithofacies One floodplain lithofacies is recognized in the Dorud Formation in the western side of the study basin: (1) silty mudstone. Silty mudstone: The most abundant floodplain lithofacies in the Dorud Formation is silty mudstone, which exists in intervals up to 5 m thick and constitutes 30–40% of logged sections. The mudstone is primarily red, although rarely there are thin ( < 2 m) intervals that are greenish gray or mottled red and greenish gray. This lithofacies is interpreted to have been deposited by floods in which clay and silt settled from suspension in standing or gently draining waters on floodplains away from active channel belts and their associated crevasse- splay and levee complexes(Reading, 1991 [7]).

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Planar–tabular cross-bedded sandstones make up most of the unit. The sandstones are medium to coarse-grained quartzarenites arranged in 5-m-thick bodies formed by cross- bedding sets defined by internal erosion or reactivation surfaces. Individual sets may reach 5 m in thickness, most of them consisting of simple foreset, that on occasions may be interrupted by internal erosion or reactivation surfaces. The characteristics of the sandstone beds of this unit indicate that its deposition took place in a point bar system (Visher, 1969[8] ; Collinson,1991[9]). These bodies are up to 60 m thick and less than 80 m wide, and are made entirely of intraformational conglomerates accumulated in small channels originated within the floodplain. Locally, ferruginous cement constitutes the major cement where the pores are completely plugged with iron-oxides. It is dominated by flat-bedding and planar cross- bedding with minor trough cross-bedding and ripple marks (fig.2). This facies was deposited in a meandering fluvial system in channels with lateral accretion movements in which point bars formed. The sand bodies composed of planar and trough cross bedding and ripple cross- lamination are interpreted as low-sinuosity channel fill deposits.

Fig. 2. Photomicrographs & Photographs of typical textures and Some facies nad in this study: (A) Horizontal-stratified red sandstone and other clastic rock. (B) Stratified-sandstone interbedded with conglomerate and cross-stratified microconglomerate. (C) Even lamination of red sandstone facies. (D) Classification of sandstone using Folk (1964) scheme. (E) Sublitharenite subfacies with some coarse quartz -Q grains. (F) Quartzarenite subfacies with hematitic cement. (G) Litharenite subfacies. (H) Microconglomerat facies.

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Petrographically, the sandstone is formed of monocrystalline quartz grains which form more than 80% of the rock content (quartz arenite & Sublitharenite). The grains range in size from fine to medium sands. They are subangular to rounded and display close-packed fabric where the grains have point, tangential and concave-convex contacts. This reflects that the sandstone had undergone a change in texture and fabric, as well as a considerable loss of its primary porosity as a result of compaction. The vertical arrangement of these facies types is indicative of repetitive, fining-upward cycles of fluvial origin. Each of these upward fining cycles is marked, from oldest to youngest, in the lithologs. The lowstand fluvial deposits (meandering river) marking the base of the Durod formation clastic facies are overlain by middle-upper Permian carbonate succession (fig.3).

Fig. 3. Depositional model for the meandering river of the lower Permian, Harzand area.

Conclusions: The Asselian–Sakmarian sequence in the Harzand area cosists mainly of clastic (Sandstone) rocks with iron-oxides in the Dorud formation. Clastic sediments in Dorud Formation were deposited in a meandering river environment. Sequence stratigraphyic analysis indicate the presence of lowstand system tract in the Dorud Formation that are related to river environment. The lower and upper boundary of the sequence is a type 1 Unconformity.

References: 1. Stepanov, D.L., Golshani, F., Stocklin, J., 1969, Upper Permian and Permian–Triassic boundary in North Iran. Rep. Geol. Surv. Iran. No.12, P.1- 71. 2. Shabanian, R., Bagheri, M., 2008, Permian in Northwest of Iran. Subcommission on Permian Stratigraphy (Permophiles). No.51 P.28-31 3. Asserto, R., 1963, The Paleozoic formations in Centeral Alborz (Iran), priliminary note, Rivista Italionadi Paleontaliae Staigrafic, 69P. 4. Folk, R. L., 1962, Spectral subdivision of limestone types in : Classification of Carbonate Rocks ( Ed. by W. E. Ham ), Mem. 1, A. A. P. G., P. 62 – 84. 5. Tucker, M.E., 2001, Sedimentary Petrology An introduction to the origin of sedimentary rock. Oxford: "Blackwell", p.262. 6. Scotese, C.R., 1997, Paleogeographic Atlas, PALEOMAP Progress Report 90-0497. Dept. Geol, Univ. Texas at Arlington, Arlington, Texas. P37 .

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7. Reading, H. G., 1991, sedimentary Environments and facies Blackwell scientific publ., 524 P. 8. Visher, G., S., 1969, Grain size distributions and depositional process, J.S.P., V. 39, P. 1074 – 1106. 9. Collinson, J. D., 1991, Alluvial Sediments, In : H. G. Reading ( Editor ), sediment tary Environments and Facies, Blackwell Scientific Publ. 20 - 62.

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The investigation of Diagenetic processes and interpretation of paragenetic sequence of Tirgan Formation, Zavin section, NE of Iran

Ahmad Saffar1, Mohammad Javad mousavi1, Habib Allah Torshizian2, Mohammad Javanbakht2

Islamic Azad University, Shahrood Branch

Islamic Azad University, Mashhad Branch, Young Reaserchers Club

Introduction The age of Tirgan Formation is early cretaceous (Barremian-Aptian) and is one of the calcareous formations in Kopet-dagh sedimentary basin (kalantari, 1969). This formation is mainly formed from orbitolina oolitic limestone which is overlain on the silissiclastic Shurijeh Formation and is underlain by shale-marly Sarcheshmeh Formation (Afshar-e-harb, 1994). Tirgan Formation in the studied area is located in 59 53 19 East longitude and 36 44 40 North latitude in the South east of Kalat-e-Naderi, Iran. The aim of this study is investigation on the processes which occurred after sedimentation in Tirgan Formation in South east of Kalat-e- Naderi. Diagenesis process is related to different agents which occurred in the marine environments near the surface (meteoric) and downward to deep burial environment (Taker and Write, 1990). Diagenetic processes in carbonate rocks consists of 6 main processes, generally: cementation, micritization, neomorphism, dissolution, compaction and dolomitization (Taker and Write, 1990; Taker and Beterst, 1990; Taker, 2001; Ehrenberg et al, 2002).

1-Cementation Cementation is one of the most important diagenetic processes which formed a hard limestone from weak sediment and occurred in the places that the great amount of intra particle fluid becomes oversaturated (Taker, 1991). The cements observed in the studied sequence are mainly carbonate type (calcite and aragonite) and a few amount of iron oxide that consists of these cements: 1) filament calcite cement (figure A) 2) blocky cement (figure B) 3) poikilotapic cement (figure C) 4) equant mosaeic cement (figure D) 5) syntaxial cement (figure E) 6) druzy cement (figure F)

2-Micritization Bioclasts and even non-skeletal grains are destructed by non calcareous alga, fungies and bacteries because of this process and a micritic cover can form around them due to this process (Taker and Write 1990, Carols 2001) (figure G)

3-Neomorphism Neomorphism in limestones is often increasingly which lead to forming the crystals with larger size

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4-Compaction Compaction process can be observed in two ways in carbonate sediments; mechanical and chemical. Mechanical compaction begins a little time after sedimentation that in mud sediments results in reducing of beds thickness and in grain sediments results to increasing the dissolution and alternately fracturing. Chemical compaction which is the result of increasing the dissolution in connecting place of grains is mainly the result of top beddings weight. If compaction is followed after cement forming, the stylolith is usually formed (Feiznia, 1377). Styloliths can form both in microfacies which are enriched of mud and the ones which are enriched of grains, in various types and forms (Lugan,Seminuc, 1976) (figure H)

5-Dissolution Dissolution in carbonate rocks may occur after sedimentation or more times after it (the time of uplifting) (Taker and Write, 1990). In studied samples, dissolution traces both can observe in the field and under the microscope.

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A B

D C

E F

H G

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Paragenetic sequence The estimated of paragenetic sequences shows the relative time of diagenetic processes effects in the studied area which formed in the three main environments: Marine, Meteoric and burial (James & Chokat, 1990, Taker, 1993). Marine diagenesis in Tirgan Formation consists of these processes: the micritization of allochems, sedimentation of syntaxial cement, drilling the sediments by organisms, physical compaction and hematitization. Diagenetic meteoritic processes in Tirgan Formation consist of dissolution of impermanent skeletal and non-skeletal grains and forming the secondary porosity such as moldic and vuggy. Forming of secondary generation of cement consists of blocky cement, druzy cement, mosaic cement and increasing neomorphism in micritic background (Sourcce and Mackenzie, 1990). Burial diagenesis in Tirgan Formation consists of poikilotapic cement, ….cement, iron blocky cement, physical and chemical sequence (Hegen,1982)

Uplifting Uplifting is the last stage of diagenetic processes. In this stage, fractures and pre-joints are formed because of uplifting in the rocks of the studied area. Fractures are formed in the rocks in various types as they activate the pre-veins and form new fractures (Vandel bril, 2008).

Conclusion Tirgan Formation is one of the kopet-dagh sedimentary basin formations which its age is early cretaceous (Barremian-Aptian) that can be observed in Zavin area. Studying of diagenesis processes in this formation shows that the most important diagenetic processes which affect these sediments consist of micritization, cementation, dissolution, physical and chemical compaction and neomorphism. Cementation mainly includes of these types: filament calcite cement, blocky cement, poikilotapic cement, equant mosaic cement, syntaxial cement and druzy cement. These processes had been effective on sediments in three followed environments: marine, meteoric and burial environment.

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Time Eogenesis Mesogenesis Telogenesis Environment Marine Meteoric Mixing Burial Uplift

Processes

Micritization

Physical

Chemical

Compaction Isopachous rim

Equant Mosaic

Syntaxial rim

Blocky

Cementation

Neomorphism

Fracturing

Reference Flugel, E., 2004, Microfacies Analysis Of Carbonate Rocks, Analyses, Interpretation and Application, Springer-verlag, Berlin, 976 pp. Choquette, P.W., and James, N.P., 1987, Diagenesis in Limestones–The Deep Burial Environment. Geoscience Canada, Clari, P.A. and Martire, L., 1996, Interplay of cementation, Mechanica; compaction, and chemical compaction in nodular limestone of the Resso Ammonitico Veronese (Middli-Upper Jurassic, Northeast Italy). Journal of Sedimentary R James, N.P., 1991, Diagenesis of carbonate sediments, a short Course: Geo.Soc. Ketzer, J.M.M., 2002, Diagenesis and Sequence Stratigraphy, Uppsala University,

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

The investigation of sedimental facies and sedimental environment of Tirgan Formation, Zavin section, NE of Iran

Ahmad Saffar1, Mohammad Javad mousavi1, Habib Allah Torshizian2, Mohammad Javanbakht2

Islamic Azad University, Shahrood Branch

Islamic Azad University, Mashhad Branch, Young Reaserchers Club

The age of Tirgan Formation is early cretaceous (Barremian-Aptian) and is one of the calcareous formations in Kopt-dagh sedimentary basin which is ranged with E-W strike in the area (Afshar-e-Harb, 1994). This formation is mainly composed of Orbitoline-Oolithic limestones which is overlain on the Shurijeh Formation and is underlain by Sarcheshmeh Formation.The studied area is located near to Zavin township in 80 Km(s) of Kalat-e-Naderi township. The thickness of mentioned formation is about 188 m in this area. The aim of this study is interpretation of Tirgan Formation sedimentary basin (Barremian-Aptian) in south east of Kalat-e-Naderi.

Explanation of microfacies Microscopic Investigation of Tirgan Formation samples in the studied section led to identifying variant microfacies which are related to open marine environmental belt (A), bar (B), lagoon (C) and tidal flats (D). Four facies complexes (A, B, C, D) in this facies are recognized which for more precisely investigation, each one is divided to several facies. These facies are numbered from deeper part of the sea toward the beach.

Open marine facies complex (A)

Mudstone facies This facies is mainly composed of calcareous mud, less than 4% bioclasts, and bivalves, brachiopods and bryozoans fragments. The fragments and grains are very fine. (Figure A)

Bioclastic Wackstone This facies is including of skeletal fragments such as brachiopod shells (3-5%), bryozoans (3- 4%) and bivalves (3%). (Figure B)

Interpretation This environment is located in sub tidal and has normal salinity. Because of great depth in this area, waves cant affect the substrate sediments, generally in these sediments, bivalves, brachiopods and bryozoans fragments show sedimentation in parts of the sea with mid depth. Also, skeletal fragments with fine to middle size, existence of micrite in the background and fossils relative to open marine show forming of these facies in open marine environment.

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B A

Bar facies complex(B) Agrogat ooid grain stone facies This facies is formed from ooid and intraclast. Ooid has abundance about 20-25% which its destruction index is 1.2-0.5 mm. The Intraclast has abundance about 10-15% which its destruction index is 1-4 mm. pelloid is one of the other non skeletal fragments which is very little (2-3%).(Figure C)

Ooid grain stone facies Ooids are the major forming fragments of this facies. Their abundance in this facies is about 30-35% which their destruction index is about 0.5-1.7. ooids cores are mainly formed of skeletal fragments. Intraclasts are one of the other non skeletal fragments which their abundance is about 7-9%. (Figure D)

Pelloid ooid grain stone facies ooids are the major forming fragments of this facies which their abundance is about 20-25% and in some parts, they become micritic which haven‘t signal structure. Their diameter is about 0.5-1.8 mm. In this facies, pelloids are viewed with the abundance about 10-13%.

Interpretation High percentage of ooids with tangent fabric and intraclasts with marine skeletal fragments shows high energy at the time of sedimentation in this facies. In addition to ooid, intraclast is also one of the important fragments in this area which the existence of this fragment in ooid grain stone and intraclast ooid grain stone facies confirms the forming of this facies beside the bar toward the lagoon. High destruction index of intraclasts and ooids confirms their forming in high energy state. Facies belt type B is equal to facies belt number 6 of Wilson model (1975) locates in Y area in Ervin model (1965).

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c D

Lagoon facies complex(C) Algal bioclastic wakstone facies In this facies, various types of skeletal grains are found beside each other which connect together by calcy mud. The main part of the particles is algal, gastropod, bivalve, brachiopod fragments. Studied algs are belonged to family Dacyclades, the genus Cylindroporella and Macroporella. (Figure E) bioclastic packstone facies The percentage of bioclastic fragments which formed this facies is: bivalve 15-20%, brachiopod 7-8%, echinoderm 3-5%, bryozoans 7-9%, green algae 3-5%.(Figure F)

Interpretation The great abundance of calcy mud with gastropod, algae, bivalve and pelloid fragments shows sedimentation of facies belt type C in a low energy environment. Great abundance of calcy mud shows lack of high energy in the environment (Flogel 2004). The facies belt type C is equal to facies belt number 7 of Wilson model (1975) and is located in Z area in Ervin model (1965).

F E

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Tidal flats facies complexes (D) Intraclastic packstone The main allochem which forms this facies is intraclast which its abundant is about 20-25%. The destruction index of intraclasts is variable between 1.4-0.5 mm. quartz is one of the terriginous particles which observed with the abundance of 4-6%.

Intraclastic ooid packstone This microscopic facies is mainly formed from ooid and intraclast which are 25-30% of allochems in this facies. The ooid destruction index is 0.3-1.4 mm and the intraclast destruction index is 0.5-4 mm. The skeletal fragments in this facies are bivalve and alga.

Bioclastic Quartz Packstone This microscopic facies is mainly formed from quartz. The abundance of quartz is about 15- 18%. The other types of terrigenous particles are feldspars and opaque minerals which have few percentage. The bioclastic fragments of this facies are bivalves and brachiopods.

Conclusion The followed conclusions are gained with studying of Tirgan Formation in Kalat area (Zavin): The thickness of Tirgan Formation is about 188m in this area which is located between Shurijeh and Sarcheshmeh Formations. The facies of Tirgan Formation is located in 4 facial belts: open marine environment, bar, lagoon and tidal flat. Regarding to the sequence of Tirgan Formation‘s facies and its comparison with nowadays environment, we can conclude that the sedimentary model of Tirgan Formation in studied section is carbonate platform, hemoclinal ramp.

Reference Afshar-Harb, A., 1994, Geology of the Kopet-Dagh. Tehran, Geological Survey of Iran, Burchette, T.P. and Wright, V.P., 1992, Carbonate ramp depositional Systems, Sedimentary Geology. Wilson, J.L., 1975, Carbonate Facies in Geological History. Adabi, M.H., 1996, Sedimentology and geochemistry of Upper Jurassic (Iran) and Precambrian (Tasmania) carbonates. Unpubl. Ph.D. Thesis, University of Tasmania, Australia,

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Petroleum System Prediction Based On Geochemical Characteristics of Hydrocarbons in the South Pars Field

Mahmoud Memariani, Hadi Kermanshahi, Roya khezerlo

Research Institute of Petroleum Industry (RIPI) West Blvd., Near Azadi Sports Complex Tehran Iran. [email protected]

Abstract The South Pars field, the world's largest independent gas reservoir with suitable exploitation potential of oil layer located on Iran-Qatar borderline in the Persian Gulf. In order to petroleum system determination, four condensate and three oil samples were subjected to intensive geochemical analyses. The condensate samples collected from Kangan and Dalan reservoirs. The analyzed oil samples were belonging to Sarvak (Maudud Mb.) and Dariyan formations. The oil samples were analyzed according routine geochemical analysis; namely column chromatography, gas chromatography and gas chromatography-mass spectrometry. In order to separate and identify the biomarker fingerprint of condensate, new methods were employed. These methods were: (I) Mild evaporation of unwanted hydrocarbons, (II) Mild oil topping for two weeks to remove medium molecular weight hydrocarbons (C8-C15), (III) Urea adduction to concentrate biomarkers containing fractions and (IV) finally, molecular analysis using GC-MS technique used as for oil samples. Different parameters of biomarker fingerprint such as, Hopanes (m/z=191) and Steranes (M/Z=217) biomarkers were calculated. Interpretation of oil samples biomarker fingerprint indicated that oils were generated from carbonate source rock which has been deposited in a anoxic condition and originated from esturine source rock with minor terrestrial organic matter. These oils were produced from mainly type II and III kerogens. Evaluation of biomarker maturity parameters are shown peak of oil window maturity for organic matter. Geochemical studies of biomarker parameters from condensate sample revealed that condensate were generated from clastic source rock and deposited in an anoxic sedimentary condition. Condensates were originated from esturine source rock with minor terrestrial organic matter too. The maturity of condensate samples is relatively high, at late oil generation stage to early gas window. Based on the correlation of geochemical properties of oil and condensate samples, two different petroleum systems are determined in South Pars field. Some of researchers believe that Permian-Triassic hydrocarbon reservoirs in Persian Gulf charged by Silurian shale. Result of this investigation confirms their theories. Consequently Kangan and Dalan reservoirs charged by Paleozoic (Silurian) petroleum system. Moreover, geochemical study results on oil samples indicated that Jurassic system (Hanifa Formation) in Arabian part of Persian Gulf probably charged South Pars oil layer.

Keyword: South Pars, Petroleum system, Biomarker, hopane, Sterane, Oil Topping, Urea adduction

Introduction The South Pars field, the world's largest independent gas reservoir with suitable exploitation potential of oil layer located on Iran-Qatar borderline in the Persian Gulf (Fig1). The Dalan and Kangan (Permian/Triassic) formations are Gas reservoirs and The Dariyan formation and Maudud member of Sarvak Formation (Cretaceous) are a known oil reservoirs in this field. One of the most important goals of this study is to determine the petroleum systems in South Pars field. In order to hydrocarbon system determination, identifying geochemical

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 characterization of source rocks is necessary. The probable source rock frequently unavailable for analysis in studied area as they are buried too deeply, Hence we used the biomarker analysis to evaluate source rocks characterization. Biomarkers are specific chemical fossils which are originated from biological inputs, and reflect the maturity, kerogen type and paleoenvironment conditions of source rocks [1, 2, 3]. Biomarker fingerprint can be used when access and direct analysis of generative probable source rock are impossible. Characterization of oils and condensates has allowed us to extend our hydrocarbon-family. This paper presents results of complementary geochemical biomarker study examining steranes and hopanes of concentrates samples from oil and condensate

Methods Three and four oil and condensate samples were selected from oil and gas reservoirs respectively. Hydrocarbon fractionation of oil samples were achieved by column chromatography using silica gel and alumina as adsorbents. In order to separate and identify the biomarker from condensate, new analytical methods were employed. These techniques were: (I) Mild evaporation of unwanted hydrocarbons, (II) Mild oil topping for two weeks to remove medium molecular weight hydrocarbons (C8-C15), and (III) Urea adduction to concentrate biomarkers containing fractions. Saturate fractions of oil and condensate sample were analyzed according to routine geochemical analysis after sample preparation; namely gas chromatography and gas chromatography-mass spectrometry. The hopane and sterane biomarker distributions were determined using the m/z=191 and m/z=217 mass fragmentogram respectively. Fragmentograms observed for triterpanes and steranes are shown in Fig. (8, 9, 10).Results of calculated parameters is shown in table (1).

Result and Discussion Biomarkers in oil can reveal the environment of deposition as marine, lacustrine, fluvio- deltaic or hypersaline, the lithology of the source rock and the thermal maturity of the source rock during generation [4]. Besides biomarker analysis is one of the best paleoenvironmental tools to identify anoxic and euxinic conditions in the water column [5]. Pr/Ph ratio has been used to indicate the redox potential of the source sediments [6]. According to these authors [6] Pr/Ph<1 ratios of oils suggest anoxic depositional conditions and suboxic environment for condensate of South Pars field. However, this interpretation should to compare with other biomarker parameters. Pristane/nC17 versus Phytane/nC18 [7] plot suggests anoxic depositional conditions for the source rock of the oils and condensate (Fig.2). These hydrocarbons were generated predominantly from type II and minor type III kerogen.

In order to lithological characteristics identification, C29/C30 Hopane ratios versus C34/C35 Homohopane [8] are plotted in Fig(3). C29/C30 Hopane ratio of oils is ranging from 0.96 to 1.21 indicating the source rock of oils is thought to be carbonate rocks. Condensates have wide range of the ratio which suggests the condensates were derived predominantly from clastic source rock. Moreover, C34/C35 ratio confirms the other interpretations of anoxic depositional environment. Based on C35s/C34s Hopane vs. C29/C30Hopane plot [9] (Fig.4), oils and condensate in south pars filed were generated from carbonate and clastic-carbonate source rock respectively.

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Huang and Meinschein (1979) [10] indicated that the ratio of C27-, C28-, C29- sterol homologs on ternary diagram might be used to differentiate depositional settings and ecosystem. Fig. (5)

Presents C27-C28-C29 sterane distribution ternary diagram for oils and condensates. Oils are genetically related being derived from an esturine source rock with minor terrestrial organic matter, while the condensate seems to be generated from source rocks with predominantly terrestrial organic matter. One of the most widely used applications of biomarkers is the measurement of thermal maturity of organic matter [11,12]. Hopanes and steranes include the biomarkers most commonly used for maturity assessment [13,14,15]. The observed triterpane and sterane maturation parameters are shown in Table (1). Plots of  versus 20S/(20S+20R) for the C29 sterane [16] are shown that oils are mature being expelled from their source at or close to the peak oil generation stage. Fig (6) indicated that condensates have high level of maturity about at first gas window stage.

In order to more attentiveness in maturity level estimating, we used C32-Hopane 22S/22S+22R versus C29 Sterane 20S/20S+20R plot [17]. This plot indicated similar maturity equals other maturity parameters (Fig.7).

Conclusions Based on geochemical investigation results such as diversity of depositional environment conditions of candidate source rock(s), differences of organic matter maturity level of kerogen, the existence of two different petroleum system for gas and oil reservoirs are distinguished. First, Jurassic petroleum system and secondly, Paleozoic petroleum system (Silurian). According Ibrahim et al. (2002) [18] South Pars oil layer probably charged by equivalent Surmeh formation in Arabian part of Persian Gulf like Hanifa formation. Some of researchers believe that Permian-Triassic hydrocarbon reservoirs in Persian Gulf charged by Silurian shale [19,20,21,22,23]. Results of this investigation confirm their findings. A Paleozoic petroleum system with hydrocarbon production from Silurian shale which has been responsible for gas accumulation in South Pars filed. Consequently Kangan and Dalan reservoirs charged by Silurian petroleum system.

Table (1): Values of biomarker parameters calculated from South Pars field oil and condensate samples

Sample Pri/P Pr/nC Ph/nC C32 C29 C29 C29/C30 C34/C35 Ts/Ts+Tm C35s/C34s %C27 %C28 %C29 No. hy 17 18 S/S+R S/S+R 

Con.1 1.31 0.47 0.51 0.77 1.4 0.63 0.51 0.79 0.5 0.61 30.53 36.64 32.22

Con.2 1.15 0.6 0.67 0.42 0.42 0.6 0.57 1.77 0.51 0.42 35.53 23.96 40.49

Con.3 1.25 0.45 0.52 0.62 1.13 0.58 0.51 0.89 0.4 0.5 28.57 34.22 36.5

Con.4 1.14 0.48 0.56 0.53 1.2 0.56 0.49 0.87 0.59 0.63 44.49 25.51 30

Maudud 0.59 0.79 0.53 0.96 0.83 0.61 0.56 1.28 0.45 0.61 39.1 25.3 35.6

U.Dariyan 0.49 0.9 1.02 1.21 0.88 0.56 0.51 1.5 0.45 0.59 36.8 19.9 44.3

L.Dariyan 0.43 0.44 0.52 0.99 1.16 0.6 0.47 1.26 0.46 0.55 41.7 26.3 32

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Fig.1. Geographic setting of South Pars filed Fig.2.Plot of Pri/nC17 Vs. Phy/nC18

Fig (3): Plot of C34/C35 vs. C29/C30 Fig (4): Plot of C35s/C34s vs. C29/C30

Fig (5): Ternary diagram of rel ative Fig (6): plot of C29 S/S+R vs. C29 

abundance for regular steranes C27, C28, C29

Fig (7): Plot of C29 S/S+R vs. C32 22S/(22S+22R)

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Fig. (8): Sample of Gas Chromatogram of oil and condensate

Fig (9): Fragmentograms of triterpanes, m/z 191 of oil and condensate samples

(10): Fragmentograms of steranes, m/z 217 of oil and condensate samples

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Reference [1]Hunt,J.M(1996).Petroleum Geochemistry and Geology.2nd Edition.W.H. Freeman and Company,New York.743p. [2,4,15] Peters K. E. and Moldowan J. M. (1993) The Biomarker Guide. Prentice Hall, Engelwood Cliffs, NJ. [3] Bordenave.M.L,(1993).Applied petroleum geochemistry,Edition Technip,Paris,524p [5] Brassell S. C., Eglinton G., Marlowe I. T., Pflaufmann U., and Sarnthein M. (1986) A new tool for climatic assessment.Nature 320, 129–133. [6]Didyk,B.M., Simoneit,B.R.T.,Brassell,S.C., and Eglinton,G.(1978) Organic geochemical indicators of paleoenvironmental conditions of sedimentation. Nature, Vol.272, p.231-222 [7] Connan ,J.,Cassou,A.M.(1980).Properties of gases and petroleum liquids derived from terrestrial kerogen at various maturation levels.Geochimica et Cosmochimica Acta,V.44,pp.1-23 [8,9] Subroto E. A., Alexander R., and Kagi R. I. (1991) 30- Norhopanes: their occurrence in sediments and crude oils. Chem. Geol. 93, 179–192. [10]Huang,W.Y.,Meinschein,W.G(1979).Sterol as ecological indicator. Geochimica et cosmochimica Acta,V.43,pp.739-745 [11] Mackenzie A. S. (1984) Application of biological markers in petroleum geochemistry. In Advances in Petroleum Geochemistry (eds. J. Brooks and D. H. Welte). Academic Press, vol. 1, pp. 115–214. [12] Radke M., Horsfield B., Littke R., and Rullko¨tter J. (1997) Maturation and petroleum generation. In Petroleum and Basin Evolution (eds. D. H. Welte, B. Horsfield, and D. R.Baker). Springer, Berlin, pp. 169–229 [13]Seifert, W.K., Moldowan, J.M., 1978. Application of steranes, terpanes and monoaromatics to the maturation, migration, and source of crude oils. Geochim. Cosmochim. Acta 42, 77–95. [14] Seifert, W.K., Moldowan, J.M., 1981. Palaeoreconstruction by biological markers. Geochim. Cosmochim. Acta 45, 783–794 [16] Seifert,W.K.,Moldowan,J.M.(1986) Use of biological marker in petroleum exploration. In: Methods in geochemistry and geophysics .Vol.24,p.261-290 [17]Ourisson,G.,Albresht,p.,Rohmer,M.(1984). The microbial origin of fossil fuels. Scientific American, v.7, pp.44-51 [18]Mohamed, I.A., Al-Saad, H., E.Kholeif,S.,2002. Chronostratigraphy, palynofacies, source rock potential, and organic thermal maturity of Jurassic rocks from Qatar, GeoArabia, vol.7, No.4, Gulf Petrolink,Bahrain [19] Mahmoud, M.D., Vaslet, D., and Al-Husseini, M.I., 1992, The Lower Silurian Qalibah Formation of Saudi Arabia-an important hydrocarbon source rock: AAPG, v.76, p.1491-1506 [20] Cole, G.A., Abu-Ali, M.A., Aoudeh, S.M., Carrigan, M.J., Chen, H.H., Colling, E.L., Gwathney, W.J., Al Hajii, A.A Halpern, H.I., Jones, P.J., Al-Sharidi, S.H., and Tobey, M.H., 1994, Organic geochemistry of Paleozoic petroleum system of Saudi Arabia: Energy and Fuels, v.8, p.1425-1442 [21]Bishop, R.S., 1995, Maturation history of the lower Paleozoic of Eastern Arabia platform, in Al- Husseini, M.I., ed., Geo-94, Middle East Petroleum Geosciences, Gulf petrolink , Manama, Bahrain, v.1.p.180-189 [22]Milner, P.A., 1998, Sourcr rock distribuation and thermal maturity in the southern Arabian Peninsula: GeoArabia, v.3, p.339-356 [23] Abu-Ali, M.A., Rudkiewicz, J.L.L McGillivray, J.G., and Behar, F., 1999, Paleozoic petroleum system Central Saudi Arabia: GeoArabia, v.4, p.321-336

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Facies Analysis, Depositional Environments and Diagenesis of the Sarvak Formation in Azadegan Oil Field

Talatnaz Eghtesadi

MS student - Islamic Azad University, North Tehran Branch No.10,east Dolatshad Alley , Farid Afshar Ave. , Zafar St. Tehran , Iran. 021-22003829 & 09125704524 [email protected] & [email protected]

Dr. Nader Kohansal Ghadimvand

Islamic Azad University, North Tehran Branch

Dr. Farid Taati

N.I.O.C. Exploration Directorate

Abstract The Sarvak Formation (Albian-Turonian) was measured 822 m in type section and mainly consists of carbonate rocks. This Formation forms the important hydrocarbon reservoir in southwest of Iran. In this research the Sarvak Formation with Cenomanian age has been investigated in some wells in Azadegan oil field in the north of the Dezful Embayment in south west Iran. This research has been focused on facies analysis, depositional environments and diagenetic processes in the Sarvak Formation. The thickness of the Sarvak Formation is varied from 608 to 637.5 meters in Azadegan wells. In these wells the Sarvak Formation is overlain by the Ilam Formation uncomfortably. It is underlain the Kazhdumi Formation with conformable contact. Based on detail sedimentological analysis over the Sarvak formation four facies associations including tidal flat, lagoon, barrier and open marine have been recognized. The detailed microfacies analysis and sedimentological criteria suggest the Sarvak was deposited in rimmed shelf carbonate setting. The most important diagenetic processes include dolomitization, calcitization, cementation, pyritization, micritization, neomorphism, compaction, dissolution and biotorbation influenced Sarvak. From the petrophysical point of view, the porosity is the most important diagenetic process in the Sarvak Formation and fracture, vuggy and moldic types are dominant porosity types in this Formation.

Keywords: Azadegan field; Sarvak Formation; Cenomanian; Facies; Rimmed shelf

1. Introduction The Azadegan oil field is located in in southwest of Iran. This structure is near the boundary between Iran and Iraq and it is 60 km far from Abadan city. The Azadegan structure was explored by geophysical operations in Abadan plain. The Sarvak Formation with Cenomanian in age forms main reservoir unit in this structure. This formation is a part of Bangestan group includes Kazhdumi, Sarvak, Surgah and Ilam Formation (James and Wynd 1965). The lower boundary of Sarvak Formation is conformable with Kazhdumi Formation. The upper contact with Ilam Formation is recognized by a discontinuity surface. In Dezful embayment and a part of Abadan plain an argillaceous unit (Laffan or Surgah Formations) separate carbonates of Sarvak from Ilam Formation. The microfacies and depositional

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 environment of Sarvak Formation have been studied by different authors (Farzdi, 1371; Keyvani,1372; Jalilian, 1375; Lasemi and Jalilian, 1376; Teymorian, 1383; Ale-Ali, 1386). In this study, microfacies analysis, depositional setting and diagenetic processes of Sarvak Formation in the wells A, B, C of Azadegan oil field have been investigated.

2. Methods of study Totally about 380 thin sections have been adopted from the cored interval. Sampling had been taken systematic and very dense (one sample in each 30 cm.). Thin sections were treated with Alizarin Red-S following Dicsone (1966) for discrimination of calcite from dolomite. Classification of carbonate rocks has been carried out based on Dunham (1962) classification and recognition of facies belts and sedimentary profile are based on Lasemy and Carrozi (1981) and Carrozi (1989).

3. Microfacies The microfacies analysis of cutting samples of whole the wells in Azadegan oil field is caused to recognize 4 facies belts (depositional environments) including tidal flat, lagoon, bar and open marine. Tidal flat facies zone (A) consist of Fenestral mudstone (A1), Fenestral bioclast benthic foram wackestone. Lagoon facies zone (B) cosist of bioclast mudstone/wackestone(B1), Benthiic foram wackestone/ Packstone (B2),Bioclast intraclast peloid packstone (B3), Orbitolin bioclast packstone/ Grainstone (B4), Intraclast orbitolin benthic foram grainstone )B5). Bar facies zone (C) consist of Rudist boundestone (C1), Peloid grainstone (C2) and open marin facies zone (D) consist of bioclast plagic foram mudstone/ wackestone (D1), Plagic foram wackestone/ packstone (D2), Intraclast bioclast packstone. A: This facies zone is generally formed from lime mud with rare benthic forams and Gastropud with fenestral fabric which are associated with early fine dolomite. Presense of dolomitos indicate internal part of a tidal flat seeting (Shinn, 1983). B: This facies zone is mainly consist of various freavent benthic forams which suggest a lagoon environment in adjacent to tidal flat (Lakhdar,2006). The skeletal allochems are abaoundant with high diversity and their association with pelloids indicate a shallow bathy met with proper saline condition and water circulation which provide a nutrient condition (Bachmann., Harsch 2006).Low diversity of found and increasing of lime mud in some facies suggest a low energy restricted lagoon (Messe,2003;Sandulli, 2004). C: This facies zone is charectrerized with aboundant Rudist. In this facies zone Echinoid, Peloid and Intraclast have been abserved. This assemblage found inparticvior Rudist abundant indicate a very high energy condition in barrier setting (Flugel, 1982; Ross and Skelton, 1993; Wilson, 1975). D: This facies zone is characterized with pelagic forams such as Hedbergella, Oligosteginid, Echinoid fragments and sponge spicules. Which indicate deep open marine setting (Simo and Lehmann, 2000). High frequency of Oligosteginid and Hedbergella suggest a very good nutrient condition in the presence of the sparse lime mud in matrix represent low energy environment in this facies zone (Adachi, 2004; Premoli-Silva and Sliter, 1994; Brasier,1995; Luciani and Cobianchi, 1999; Birkeland,1987). The specific faunal assemblage in this facies zone can survie in normal saline open marine condition (Heckel,1972; Sanders and Hofling, 2000; Flugel, 2004). In sammrized, presence of high amount of lime mud suggest a calm realm with no agitation.

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4. Depositional Model According to the results of Sedimentological studies of the Sarvak Formation in Azadegan field and comparison to previous studies and regarding to Walter's law, it seems that the Sarvak Formation has been deposited in a rimmed shelf carbonate platform.

5. Diagenesis and its Effect on Reservoir Charaterizaiton Different diagenetic process affected the studied interval, include compaction, dissolution, calcitization, cementation, neomorphism, bioturbation, dolomitization and fracturing. Among all, dissolution and fracturing are the most important factors which cause to develop porosity and have positive effect on reservoir quality .

6. Conclusion 1-Four facies belts including tidal flat, lagoon, bar and open marin have been recognized. 2-Based on recognized facies association of Sarvak and with comparison of them to modern environments a rimmed shelf carbonate platform setting for deposition of the Sarvak in studied area has been suggested. 3-The compaction, dissolution, calcitization, cementation, neomorphism, bioturbation, dolomitization and fracturing are main recognized diagenetic process in Sarvak.

1. Fenestral mudstone 2. Benthick foram wackestone

3. Rudist boundestone 4. Plagic foram wackestone

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5. Chemical Compaction (Stylolit) 6. Physical Compaction

7.Drusy Cement 8. Fracture Porosity

References [1] Adachi., Ezaki, y., Liu, J., The origins of peloids immediately after the end- Permian extinction, Guizhou Province, South China, Sedimentary Geology (2004). [2] Ale- Ali., Microfacies analysis and depositional environment of the Sarvak Formation in the North of ,A Symposium, geology of the Iran, (1386). [3] Bachmann,M.,Harsch,F., Lower Cretaceous carbonate platform of the eastern Levant (Galilee and the Golan Heights): Stratigraphy and second- order sea-level change. Cretaceous Research (2006). [4] Birkeland, C., Nutrient availability as a major determinant of differences among coastal hard- substratum communities in different regions of the tropics. In: C., Birkeland (ed.): Comparison between Atlantic and Pacific tropical marine coastal ecosystems: community structure, ecological processes, and productivity: UNESCO Reports in Marine Science (1987). [5] Brasier, M.D., Fossil indicators of nutrient levels. 1: Eutrophication and climate change. In: D.W. Bosence, P.A. Allison (eds.): Marine palaeoenvironmental analysis from fossils, Geological Society Special Publication, (1995). [6] Burchette, T.P. and Wright,V.P., Carbonate ramp depositional system, Sedimentary Geology (1992). [7] Carozzi, A. V., Carbonate Rocks Depositional Model. Prentice Hall, New Jersey (1989) [8] Dunham, R. J., Classification of carbonate rocks according to depositional texture, In, W.H. Ham(ed), Classification of Carbonate Rocks, A Symposium, American Association of Petroleum Geologists Mem (1962).

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[9] Farzdi., Depositional environment and microfacies of the Sarvak Formation of the Bangestan group in the Nar anticline, Islamic Azad University North of Tehran Branch, M.Sc Thesis, (1371). [10] Flugel, E., Microfacies Analysis of Limestones: Springer- Verlag, Berlin (1982). [11] Flugel, E., Microfacies of carbonate Rocks.Analysis, Interpretation and Application New York, Springer Verlag (2004). [12] Heckel, P.H., Recognition of ancient sedimentary environments, In: Rigb, J.k. and Hamblin, W.K.(ed).Special Publicatin (1972). [13] Jalilian., Microfacies and depositional environment of the Sarvak Formation in the Bangestan and Lorestan mounts, M,Sc Thesis, (1375). [14] James, G.A., and Wynd, J.D., Stratigraphy nomemenclature of Iranian oil Constortium Agreement area, American Assosiation of Petrololeum Geologist Bulletin (1965). [15] Keyvani., Microfacies and depositional environment and history diagenesis of the Sarvak and Ilam Formations in the North Dezful oil field, Islamic Azad University North of Tehran Branch, M.Sc Thesis, (1372). [16] Lakhdar, R., Soussi, M., Ben Ismail, M., and Rabet,A., A Mediterranean Holocene coatal lagoon under arid Boujmel SE Tunisia, Palaeogeography, Palaeoclimatography, Palaeoecology (2006). [17] Lasemi, Y. and Carozzi, A. V., Carbonate microfacies and depositional environment of the Kinkaid Formation (Upper Mississippian) of the Illinois Basin,USA, VIII Congress Geol. Saluis, Actas, II (1981). [18] Lasemi and Jalilian., Microfacies and depositional environment of the Sarvak Formation in the Khuzestan and Lorestan, Journal of geology, (1376). [19] Luciani, V. and Cobianchi, M., The Bonarelli level and other black shales in the Cenomanian- Turonian of the northeastern dolomites (Italy): calcareous nannofossil and foraminiferal data: Cretaceous Research, (1999). [20] Messe, J.P., Fenerci, M., Pernarcie, E., Palaeobathymetric reconstruction of peritidal carbonates late Barremian, Urgonian, sequences of Provence (SE France), Palaeogeography, Palaeoclimatology, Palaeoecology (2003). [21] Papazzoni, C.A. and Trevisani, E., Facies analysis, palaeoenvironmental reconstruction, and biostratigraphy of the‖Pesciara di Boica‖ (Verona, northern Italy), An early Eocene Fossil- Lagerstatte, Palaeogeography, Palaeoclimatology, Palaeoecology (2006). [22] Premoli-Silva, I. and Sliter, W.V., Cretaceous planktonic foraminiferal biostratigraphy and evolutionary trends from the Bottaccione section, Gubbio, Italy: Paleontographia Italica, (1994). [23] Rasser, M.W., Scheibner, C. and Mutti, M., A palaeoenvironmental standard section for Early llerdian tropical carbonate factories, (Corbieres, France; Pyrenees, Spain), Facies (2005). [24] Ross, D. and Skelton, P.W., Rudist formations of Cretaceous: a palaeoecological, sedimentological and stratigraphical review: Sedimentology Review, (1993). [25] Sanders, D. and Hofling, R., Carbonate deposition in mixed siliciclastic carbonate environments on top of an orogenic wedge (Late Cretaceous, Northern Calcareous Alps, Austria), Sedimentary Geology (2000). [26] Sandulli,R., The barremian carbonate platform strata of the Montenegro Dinarids near Podgorica, a cyclostratigraphic study. Cretaceous Research ( 2004).

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[27] Schulze, F., Kuss, J. and Marzouk, A., Platform configuration, microfacies and cyclicities of the upper Albian to Turonian of west-central Jordan, Facies, (2005). [28] Shinn,E.A., Tidal flat environment, In Scholle,P.A.,Bebout,.G., and Moore, C.H. (eds.), Carbonate Depositional Environments, AAPG Memoir (1983). [29] Simo (Toni),J.A., and Lehmann, P.J., Diagenetic history of Pipe Creek J.R., Reef, Solurian, North Centeral Indian, U.S.A., Journal of Sedimentar- Research (2000). [30] Teymorian., Microfacies and depositional environment of the Sarvak Formation in the Khuzestan, A Symposium, geology of the Iran, (1383). [31] Walter, M.R., Stromatolites: the main geological source of information on the evolution of the early benthos, In: Bengton,S., (ed), Early Life on Earth. Columbia University Press, New York (1994). [32] Wilson, V.P., Carbonate Facies in Geologic History, Springer- Verlag, New York (1975).

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Experiments on Dispersion in a Matrix-Fracture System

M.Yousefi Khoshdarregi *, A.Sanati**, M. Allahayri***

*M.Sc. in Petroleum Engineering, Petroleum University of Technology, Ahwaz, Iran

**M.Sc. in Petroleum Engineering, Faculty Staff of Azad University of Tabas, Iran [email protected]

***M.Sc. in Petroleum Engineering, Faculty Staff of Azad University of Tabas, Iran [email protected]

Abstract Dispersion of fluids flowing through porous media is an important phenomenon in miscible displacement. Dispersion causes instability of miscible displacement flooding; therefore, to obtain and maintain the miscibility zone, the porous medium dispersivity should be considered in displacing fluid volume calculation. Many works have been carried out to investigate the dispersion phenomenon in porous media in terms of theory, laboratory experiments and modeling. What is still necessary is to study the effects of presence of fracture in a porous medium on dispersion coefficient or dispersivity. In this work dispersion phenomenon in a fractured porous medium has been investigated through a series of miscible displacement tests on homogeneous sandstone core samples. Tests were repeated on the same core samples with induced fracture in the flow direction. The effects of fracture on miscible displacement flooding have been studied by comparison of the results of dispersion tests in the absence and presence of fracture. In the presence of fracture, breakthrough time reduced and the tail of effluent S-shaped curve smeared. Moreover, the slope of S-shaped curve at 1 pore volume of injected fluid was lower than homogeneous case which means dispersion coefficient increased. The results presented in this work provide an insight to the understanding of dispersion phenomenon for modeling of miscible displacement process through naturally fractured reservoirs.

Introduction In most of the enhanced recovery processes such as miscible drives, carbon dioxide flooding, as well as other recovery methods, mixing of two miscible fluids in a porous medium plays a very important role. Many studies have been devoted to mechanics of miscible displacement, focusing on the longitudinal and transverse dispersion. As one miscible fluid displaces another, the displacing solution continuously mixes with the resident fluid, so that the arrival of the displacing solution at a given point in the porous medium is characterized by a gradual change in the solution concentration from that of the original fluid to that of the invading fluid. This mixing or interfusing of the two fluids, due to both molecular diffusion and convection, is termed dispersion.

1. Need for Research Dispersion theory is important in the study of the miscible recovery of oil, movement of trace contaminants such as radioactive waste and heavy metals, Infiltration of saltwater in groundwater systems, chromatography, fluid– solid catalytic and non-catalytic reactions, etc. Diffusion and dispersion in porous rocks are of current interest to the oil industry. Miscible displacement has been used successfully in enhanced oil recovery (EOR) processes. The

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 processes promise high recovery from homogeneous reservoirs, but only a small fraction of reservoir volume may be displaced at the time displacing fluid breaks through to the producing well because of the heterogeneity of reservoir. To improve the process of miscible displacement, it is very important to understand well the heterogeneity of the reservoir. Dispersion in miscible displacement is a characteristic of porous media. It is influenced mainly by the heterogeneity of reservoir and fluid flowing conditions. S-shaped breakthrough curves are typically used to describe the dispersion phenomenon in porous media. In a recovery process utilizing a zone of miscible fluid, there is the possibility of losing miscibility by dissipating the miscible fluid or by ‗channeling‘ or ‗fingering‘ through the miscible zone. Diffusion and dispersion are two of the mechanisms that may lead to mixing and dissipation of the slug. On the other hand, dispersion may tend to damp-out viscous fingers which may be channeling through the miscible slug. Hence, dispersion may be detrimental or beneficial (if it prevents fingering through the miscible zone). Therefore, it is doubly important that we understand these processes.

2. Experimental Methods and Procedures The experimental apparatus used for this study was designed to isolate and study the effect of fracture on dispersion phenomena. In order to isolate the dispersion phenomena due to fracture, several interfering processes had to be eliminated. These processes include adsorption of the displaced and displacing fluid on the surface of the porous medium; and dispersive effects due to viscosity and density differences between the displaced and displacing fluids.

2.1. Selection of Core Samples and Fluids Two groups of relatively clean sandstone samples were tested (Figure 1, Figure 2). Sandstone was used because of its high permeability and porosity. During the tests, minimum volume of each fluid sample used for RI measurement was about 2 cc, so pore volume was a crucial parameter in this study. An increase in length of core samples could supply more pore volume, but some limitations in laboratory apparatuses restricted core samples length to be maximum 15 cm long. Dimensions of core samples are presented in Tables 1, and Table 2. To conduct miscible displacement tests for determining the dispersion coefficient, two fluids are necessary which must meet the following requirements:  Completely miscible,  Equal viscosities and equal densities,  Wide range of refractive indices,  No chemical reactions with rock matrix,  No adsorption to rock matrix,  Easily to get and cost effective,  Easily to clean for repeat runs,  Nonvolatile,  Newtonian behavior. Based on these considerations, Naphtha and Gasoil were selected. As shown in Table 3, these two fluids meet all the above requirements except their viscosities. So naphtha with lower

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 viscosity was used as displaced fluid, while gasoil with higher viscosity was used as displacing fluid to avoid viscose fingering during tests.

2.2. Experimental Procedure Different experimental procedures and techniques were required in this investigation. The experimental procedure for this study is divided into two parts. Part one is the experiment on conventional sandstone core samples, and part two is the same experiment on fractured core samples. All core samples were vacuumed and saturate with gasoil. After that, their pore volume and permeability were measured using core flood apparatus as shown in Figure 3.The results of pore volume and permeability measurements are shown in Table 4. To conduct the dispersion measurements on core samples, a miscible displacement test is so designed that an s-shaped concentration profile can be obtained. For the miscible displacement tests, two major pieces of equipment required are (1) a constant-rate pump for fluid injection, and (2) a refractometer for measuring the effluent concentration. If the refractive indices of two fluids are known, their percentage in a mixture can be determined from the measured refractive index for this mixture. Therefore, it is necessary to calibrate this device for the selected fluids for miscible displacements (Gasoil and Naphtha). The calibration procedure is to measure the refractive indices of mixtures with a variety of percentages of the two fluids such as 0/100, 10/90, 20/80, and so on until 100/0. The relationship between fluid percentage and refractive index shows a straight line for gasoil and naphtha as shown in Figure 4. From this plot, measuring the refractive index of a mixture, the percentages of the components can be easily found. Except the favorable viscosities and densities of the two fluids, an appropriate flow rate for the miscible displacement tests is also critical to obtain a unique value of dispersivity. Darcy‘s law is applicable only in laminar flow regime, so the test condition should be such that produces a laminar flow regime for fluids flowing through porous media. From previous section (permeability measurement) we can find an appropriate flow rate which produces a laminar flow regime for flow. If we plot flow rate vs. pressure difference, wherever they relate to each other linearly, that part of flow is laminar. When the trend deviates from linearity, the flow regime goes to turbulent flow. Based on this technique, flow rate of 1cc/min was selected for conducting dispersion tests. Based on the above description, the procedure of conducting a miscible displacement can be described below: The system setup is illustrated in Figure 3. At the end of permeability measurement section, the pump injects displaced fluid (naphtha) at 1cc/min flow rate until the pressure drop stabilized. Then both inlet and outlet valves of core holder were closed at the same time to keep the pressure of fluid inside core holder constant. After that, fluid vessel and all connection lines were cleaned and filled with displacing fluid (gasoil). Pump started to inject gasoil at 1cc/min into the core holder, but both valves were closed. When the injection pressure reached the pressure inside core holder, both valves were opened and at the same time, timer started. The effluent fluid was collected using sampling tubes and the time of switching tubes was recorded. Each tube collected 1 to 4 cc of fluid flowing out of core holder related to the time

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 of sampling. Sampling intervals at the start and end of displacement test were longer than sampling intervals in the middle of test. The refractive index of each sample was analyzed using a refractometer, while the concentration was calculated using calibration curves. Once the effluent fluid consisted entirely of the displacing fluid, the test was terminated. As mentioned before, naphtha and gasoil were used as displaced and displacing fluids respectively. Results of dispersion tests on each group of core samples are shown in Figure 5 and Figure 6. In these two Figures relative concentration versus injected pore volume of displacing fluid is plotted. As can be seen, in two figures relative concentration of 0.5 is achieved at 1 pore volume of injected fluid. This shows that these two core sample groups act like homogeneous porous media. Figure 7 shows dispersion test results of two core sample groups together. These tests conducted on fracture core samples, the same as previous part, and results of dispersion tests on each group of core samples are shown in Figure 8 and Figure 9. In these Figures relative concentration versus injected pore volume of displacing fluid is plotted. Figure 10 shows dispersion test results of two core sample groups together. As can be seen in Figure 10, fracture systems of both groups have similar results. Both of them at one pore volume of injected fluid achieve a ―0.6‖ relative concentration. Also, in Figure 11 and Figure 12 results of dispersion tests on each group of core samples with fracture and without fracture are shown together. Qualitative effect of fracture on dispersion effluent curve can be seen in these two Figures.

Conclusion The objective of this Thesis is to study the effect of fractures on dispersion during miscible displacement flooding. Based on the results obtained from different experiments, the following conclusions are made:  In a qualitative pint of view, results of tests conducted on conventional porous media is similar to results of a homogeneous porous media in which relative concentration of 0.5 will achieve at one pore volume injection of displacing fluid.  In a qualitative point of view, the induced fracture will reduce breakthrough time. Moreover, for core samples of group No. 1 and group No. 2, near one pore volume injection of displacing fluid, relative effluent concentration is greater than 0.5. Also, 100% displacement will achieve at higher pore volume injection than the case with nonfractured core samples.

References 1- Dutta, S., 1984, An Experimental Investigation of Dispersivity and its Role as an Oil Reservoir Rock Property: MSc Thesis, University of Oklahoma 2- Sandrea, R., 1974, Dynamics of Petroleum Reservoirs under Gas Injection: Gulf Publishing Company, Houston, Texas. 3- Niemann, E.H., Greenkorn R.A., and Eckert, R.E., 1971, Dispersion During Flow in Nonuniform, Heterogeneous Porous Media: SPE Paper No. 3365. 4- Chen, S., 1991, Investigation of Dispersivity as a Reservoir Rock Characteristic and its Determination from Well Logs: PhD Thesis, University of Oklahoma.

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5- Fred, I. and Stalkup J, 1984, Miscible Displacement: SPE Monograph Series. 6- K. M. G. Li, 1983, Random Choice Method for Treating the Convection-Diffusion Equation: SPE Paper No. 12237

Table 1: Dimensions of Group No.1 Core Samples Sample No. Type Diameter (mm) Length (mm) No. 1-1 Sandstone 37.63 43.01 No. 1-2 Sandstone 37.63 37.30 No. 1-3 Sandstone 37.63 36.33 No. 1-4 Sandstone 37.63 36.21 Total Sandstone 37.63 152.85 Table 2: Dimensions of Group No.2 Core Samples Sample No. Type Diameter (mm) Length (mm) No. 2-1 Sandstone 37.78 35.05 No. 2-2 Sandstone 37.78 36.33 No. 2-3 Sandstone 37.78 41.83 No. 2-4 Sandstone 37.78 35.21 Total Sandstone 37.78 148.42 Table 3: Physical Properties of Naphtha and Gasoil at Room Conditions (P=14.7 psi, T=25 ̊ C) Properties Naphtha Gasoil Density, g/cm3 0.794 0.824 Viscosity, cp 3.86 9.04 Refractive Index 1.4411 1.4606 Table 4: Pore Volume and Permeability of Each Group of Core Samples Group No. No.1 No.2 Pore volume (cc) before Fracturing 26.26 30.35 Pore volume (cc) after Fracturing 25.38 29.83 Permeability (md) before Fracturing 133 179 Permeability (md) after Fracturing 195 397

Figure 1: Core Samples of Group No.1 Figure 2: Core Samples of Group No.2

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Figure 3: A Schematic Diagram of System Setup

Figure 4: Calibration Curve Figure 5: Dispersion Test on Non- Fractured Core Group No.1

Figure 6: Dispersion Test on Non-Fractured Figure 7: Dispersion Test on Two Non- Core Group No.2 Fractured Core Sample Groups

Figure 8: Dispersion Test on Fractured Figure 9: Dispersion Test on Fractured Group No.1 Group No.2

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Figure 10: Dispersion Test on Two Fractured Core Sample Groups

Figure 11: Comparison of Dispersion Test on Fractured and Non-fractured Group No.1

Figure 12: Comparison Dispersion Test on Fractured and Non-fractured Group No.2

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Study of planktonic morphotype of the Abderaz Formation at type section,IRAN

M.Shafiee Ardestani1,E.Ghaseminejad2, M.Vahidinia1, M.Asgharian rostami1, B.Balmaki3*

1Faculty of Science, Department of Geology, Ferdowsi University of Mashhad, Mashhad, Iran

2Faculty of Science, Department of Geology, university of Tehran, Tehran, Iran

3Faculty of Science, Department of Geology, Payame Noor university of Tehran, Tehran, Iran E-mail: Behnaz [email protected] Abstract Abderaz Formation at its type section with an age of Turonian-Early Campanian and a thickness of 300 m contains light grey shale and marl. The study of the planktonic foraminifera in isolated form led to differentiate three morphotype groups. The first group is characterized by trochospiral tests usually indicate shallow waters, the second group contains forms with strong ornamentations and the primary keels representing mid waters and finally compact trochospiral tests with keels known as deep water indices are included in the third group. Studies on the morphotypes showed a regressive cycle for Abderaz Formation.

Keywords: Abderaz Formation, Foraminifera, morphotype

Introduction The Study on the morphotypes and planktonic to benthic ratio was the major aim of the research.This study was intended to explore the marine sedimentation of Abderaz Formation in (outer neritic-upper bathyal) restrict. Then 168 SEM images have been obtained and demonstrated in frame of 1 plate. Material and Method The section studied is located about 1 km to the Muzduran, north eastern Mashhad (a city of Iran), Kopet Dagh basin. At this locality (E: 60, o33/, 00//, N: 360, 10/, 40//)(Fig1). Type section of Abderaz Formation has 300m thickness. At the typical gap such as all regions under the surface sub-contact of Abderaz Formation are un-correlated with Aitamir Formation. But it supper layer with Abtalkh Formation is in continuous correlation. The upper layer has elected as chalk limestone upper border. A total of 130 samples were collected from the section,but Only102 samples were included in study, 7 samples due to the existence of salvation effects and 21samples was obtained from reworking damages that were excluded from the study. Which were soaked in water with diluted hydrogen peroxide, washed through 63μm, 150μm and 250μm sieves, and dried until clean foraminiferal residues were recovered. About 200- 300 individual swere picked up for each sample in two size fractions (63-150μm and >150μm) and mounted on dark cardboard slides for identification. These two size fractions were analyzed in order to obtain statistically significant representatives of the small and large groups Species identifications arebased on(Caron, 1985, Robaszynski and Caron, 1983-1984, 1995 Loeblich and Tappan, 1988, Nederbragt, 1990). Fig1. The geographical map and the ways to the region of the study.

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Discussion Groups of planktonic morphotyes are distinguished by depth of living (Hart, 1980a, Hart, 1980b , Wonders 1980, Keller, 1999) (Fig2). Those are consisting of: 1- Shallow area faunas Heterohelix and Hedbergella and a big part of Hedbergella small samples like Globotruncanids genus are related to faunas of shallow epicontinental seas or the border sea (Eicher, 1969, Eicher and Worstell, 1970, Sliter 1972). 2- Middle water faunas Praeglobotruncana and Whiteinella are related to this fauna. 3- Deep water faunas (lower than 100) These faunas were counted like keeled shapes there were 300 samples in the size of 120 mesh ompletely by chance, from every samples were counted that the result of this count shows at the First of successions and the time middle Turonian morphotype group one was conquering and the Amount of the morphotype group 3 and %P was les in the area that this paragraph. in the late Turonian the group of morphotype three was increasing in the area that it indicated the proportional increasing of depth in the area and by this time portico structure has been larger and in umbilical structure is born in this unicellular, and in Coniacian time has decreased the amount of morphotype three in the area again and the members of morphotype group one increased with the less %P in the area again and during Coniacian to Santonian the members of morphotype group 3(M3) with %Pincrease in the area for another time and in Santonian time, sea water shows a vacillation mood in the above-mentioned section . Also the planktonic to benthic ratio which explains that at the deposits 400 meter at total part of in this Formation. This study was intended to explore the marine sedimentation of Abderaz Formation in (outer neritic-upper bathyal) restrict and the provided curves from morphotypes changes are in full agreement with the curves of the sea level changes and planktonic foraminifer to epifauna benthic ratio(Fig2). Fig2-Comparison of planktonic morphotype curves with %P) M1= Morphotype group1, M2= Morphotype group2, M3= Morphotype group3, %P=percentage of planktonic foraminifera) Result Groups of planktonic morphotyes are distinguished by depth of living that is consisting of: 1- Shallow area faunas 2- Middle water faunas 3- Deep water faunas (lower than 100) in the time of middle Turonian simultaneous with subtraction of the percent of morphotype group three that indicates the dwindling of proportional in mentioned section. %Pincreases but in the late Turonian that the percent of morphotype three increases that it would indicated the propotional of depth increasing in area and the structured shapes in vicinity has increased and the structured shaped (tegilla) recently has born and in Coniacian time the morphotype group three diminished again and %Pincrease and in Coniacian -Santonian boundary by increasing the shapes of morphotype three and %Pbecame the most in this time. that this affair it is because of the advent of Globotrancana and increasing the number of them in Santonian time but in the late Santonian and the early Campanian by diminishing the percent of morphotype three and increasing morphotype one , the lip shapes became more in area. This study was intended to explore the marine sedimentation of Abderaz Formation in (outer neritic-upper bathyal) restrict and the provided

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 curves from morphotypes changes are in full agreement with the curves of the sea level changes and planktonic foraminifer to epifauna benthic ratio.

Acknowledgments This study was supported by Tehran University of Sciences Research Council, National Museum of Tehran University, Tehran, Iran and Razi Institute of Metalogy, Division of SEM, Karaj, Iran

References Caron M. Cretaceous planktic foraminifera. In: Bolli H.M., Saunders J.B., and Perch Nielsen, K. (Eds). Plankton stratigraphy. Cambridge University Press. pp. 17-86 (1985). Eicher, D.L.. Cenomanian & Turonian planktonic foraminifera from the Western Interior of the United States. In: Bronni- mann, P., Renz, H.H. (Eds.), Proceedings of the First International Conference on Planktonic Microfossils, vol. 2. E.J. Brill, Leiden, pp. 163–174 , (1969a). Eicher,D.l. Cenomanian Turonian plankton foraminifera from the western interior of the United State. In: Bronnimann, P & Renz., H.H (Editors) proceeding of the First International Conference on planktonic Microfossils, 2, 163-174.(1969b). Eicher, D.L. & Worstell, P.. Cenomanian & Turonian, foraminifera from the Great Plains, United States.Micropaleontology, 16, 296-324.(1970). Hart,M.B., The recognition of Mid-cretaceous sea level changes by means of foraminifera. Cretaceous Research, I, 289-297. (1980a). Hart,M. B.. A water depth model for the evolution of the planktonic foraminifera. Nature, 286,252- 254.(1980b). Keller, G., The Cretaceous-Tertiary Mass extinction in planktonic foraminifera:Biotic constrains for catastrophe theories, in: Macleod,N., & G.Keller,Cretaceous-Tertiary mass extions:Biotic & environmental changes,p.49-83, (1999) Loeblich A., Tappan H. Foraminiferal genera and their classification; Van Nostrand Reinhold Company, 970pp. 847 plates, (1988). Nederbragt A.J. Maastrichtian Heterohelicidae (planktonic foraminifera) from the North West Atlantic.Micropaleontology, 8: 183–206 (1990). Premoli Silva, I., Sliter, W.V.,. Cretaceous paleoceanography: evidence from planktonic foraminiferal evolution. Geology. Soc Am. Spec.Pap., vol. 332, pp. 301–328. (1999). Robaszynski F., Caron M. Foraminifères planctoniques du Crétacé: commentaire de la zonation Europe- Méditerranée. Bull. Soc. Geol. Fr, 166: 681-692 (1995). Robaszynski F., Caron M., Gonzales-Donoso J.-M., Wonders A.A.H. and the European Working Group on Planktonic Foraminifera; Atlas of Late Cretaceous globotruncanids; Revista Micropaleontologia, 26(3-4):145-305 (1983-1984). Sliter. W.V., Upper Cretaceous planktonic foraminiferal zoogeography &ecology-eastern Pacific margin. Palaeogeography, Palaeoclimatology, Palaeoecology, v12, p.15-31, (1972).

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Wonders, A. A.. Middle & late Cretaceous planktonic Foraminifera of the western Mediterranean area. Utrecht Micropaleontology Bulletin, 24, 1-158, (1980).

Fig 1.Location map of the studied area in the Iran

Fig 2.Determining Sea level change by Morphotype planktonic foraminifera

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GEOLOGY AND MINERALIZATION OF BiKILAL PHOSPHATE DEPOSIT, WESTERN ETHIOPIA, IMPLICATION AND OUTLINE OF GABBRO INTRUSION TO EAST AFRICA ZONE.

Wondafrash Mammo Ghebre

Geological Survey of Ethiopia, P.O.Box 2302, Addis Ababa, Ethiopia, Email address: [email protected]

ABSTRACT The Bikilal layered gabbro-complex is composed of zones/layers/ of olivine/ pyroxene gabbro and hornblende gabbro. Within the hornblende gabbro,repeated lenses-like thin and elongated bodies of hornblendite are found intimately associated with massive and disseminated ilmenite-magnetite bodies,in places with apatite. Petrological examination of the hornblende gabbro shows50-55% hornblende, 40-45% plagioclase, 5-7% opaque minerals/ilmenite + magnetite/, and 5-15% apatite and that of hornblendite shows 75% hornblende, 10-15% apatite, 10- 15% ilmenite and rare sulphides,and traces of Uranium. Regardless of the type of lithological units, entirely based on phosphate (P2O5) assay values of chip, channel and, core samples, two main zones of phosphate mineralization, upper and lower zones, were identified and delineated. The strike length of the upper zone is measured to be 1600m. There are two ain layers of phosphate mineralization in the upper zone, at which the average thickness of each layer to be 30m and 40m respectively. The strike length of the lower zone measured to be 3000m having a thickness within a range of 60m to 200m. The minable reserve of Soji-Bikilal phosphate deposit to be 181 million tons, at a grade of 3.5% P2O5. Preliminary beneficiation trial reveals merchant grade concentrate, at which the overall weight recoveries is in the range of 3-5%. The Radioactivity of Uranium is not determined and hence reevaluation of thephosphate rock for Uranium content should be analyzed. Similar Gabbros intrusions occur in Western Ethiopia and in East Africa which should be assessed for phosphate potential to develop the fertilizer potential of the East Africa Region.

Key words; Phosphate;Apatite; Hornblende gabbro; Hornblendite; Soji Bikilal;

INTRODUCTION A project was initiated to assess and locate local phosphate resources in Ethiopia. Investigations were made on some of the potential resources of phosphate, namely, the esozoic-Cenozoic rocks, the Precambrian metasedimentary sequences and the intrusive rocks of alkaline basic- ultrabasic rocks. Consequently, the Bikilal layered gabbro complex has been found promising and systematic exploration activities for apatite were conducted on it since 1986. Soji-Bikilal is located in western Welega zone of the Oromia National Regional State, 24-km NNE of Gimbi town. Gimbi is 440 km west of Addis Abeba. The project area is geographically bounded between 35o52'37"E - 35o53'41"E, and 9o18'30"N - 9o19'42"N. As a result of successive geological exploration works, a target area of 4 km2 was selected and 18 profile lines of 200 m. spacing were cut and a number of pits dug at an interval of 40 m. along the lines. Fifteen trenches were also excavated between the profile lines to confirm the strike continuity of the apatite bearing bodies (Wondafrash Mamo, 1997).

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Drilling work was started with a Purpose to determine the strike, dip angle and direction as well as thickness of the apatite-bearing hornblende gabbro and hornblendite units on the selected upper and lower zones of the target area, along with the core sampling for chemical analysis, petrographic study and mineral separation trials. A total of thirty boreholes were drilled to a total meterage of 7159.73Lm. and 5534 core samples were collected. Two strategies were designed to determine the strike and dip of the lithlogical units, which were the bases to decide the angle and azimuth of drilling. The drilling work was conducted by truck mounted drilling rigs fit with diamond bits. As the area is covered by gabbroic complex and the dip vary from place to place within a shorter distance, so the attitudes of the lithology need to be determined prior to intensive drilling. ―Three point problem method‖ is applied to determine the strike and dip of the lithological units of the upper zone while, ―intersection angle measurement method‖ applied for the lower zone to determine the dipping of the lithology. The average dip angle is calculated to be 430 towards 2250 (SW) and the strike measured to be 3150 – 1350 (NW-SE). Accordingly 10 vertical boreholes were drilled, at an interval of 70mts following the strike and down dip of the apatite bearing litholgy of the upper zone. Concerning the lower zone, a vertical test borehole designated as BK 603, and an inclined test borehole, BK604, were drilled to determine the dipping of the lithology of the lower zone by an intersection angle measurement method. Shallow angle of intersection (150- 200) were measured from the core samples of the vertical test borehole, while an 4 intersection angle ranging from 450-500 were measured from the core samples of the inclined test borehole. This implies that the dipping of the lithology in the lower zone to be steep (700- 750). Therefore, it is decided to drill the successive boreholes at 600 inclination, so as to intersect different lithological units, with a minimum depth of drilling. Accordingly, 15 inclined boreholes were drilled at 60o inclination towards N and NE azimuth, following the strike of the apatite bearing lithology of the lower zone, at a spacing of 200m. Description of each lithological units supported by petrological examination are described as follows; Pegmatites,Olivine/pyroxene Gabbro,Hornblende Gabbro(Apatite Bearing Gabbro and Apatite bearing Hornblendite , Anorthosite and Metasediment.

Apatite bearing hornblende Gabbro The major apatite-bearing hornblende gabbro bodies are distributed at the southwestern and northern part of the project area, with an E-W, NW-SE and N-S strike and southerly and south westerly dip at 400-450, on the southwestern part and at 700-750 on the central northern and northeastern part of the target area. The unit is generally greenish grey with an average grain-size of 2-3 mm /mediumgrained/. It varies from mesocratic to melanocratic with an average mineral composition of 50-55 % hornblende, 40-45 % plagioclase, 5-15 % apatite, 5-7 % ilmenite+magnetite, and rare sulphides. The melanocratic variety is the dominant lithological unit in the lower zone and is the chief host for apatite mineralization, where the apatite content reaches up to 15%. The mesocratic variety is more common on the upper zone and with relatively less content of apatite, usually not exceeding 5-7 % (Gallon, 1997)

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Plate-1 Excavation of Trenching on Phosphate Rock Area Apatite bearing hornblendite The major apatite bearing hornblendite bodies are distributed at the central and southeastern part of the target area. The apatite-bearing hornblendite is dark-greenishgrey, and is very fine grained /< 1 mm/. It generally shows orientation of minerals and banding but is rarely massive. It occurs as concordant, elongated, subparallel lenticular bodies of variable dimension separated by 5 meso-melanocratic hornblende gabbro. Contacts are usually abrupt but gradational composition is also known. The mineral contents are identified as 75 % hornblende, 10- 15 % apatite, with 10-15 % ilmenite and rare sulphides. Gray colour and fine-grained apatite-magnetite-ilmenite-trimolite-actinolite-disseminated ore assemblage is restricted in the lower-zone in association with the apatite-bearing hornblendite. In some places such variety is slightly Chloritized in which the chlorite and hornblende intermix together. Petrological examination of the samples also shows mineral compositions of 70-75 % tremolite-actinolite, 15-18 % ilmenite + magnetite and 5-12 % apatite with hypidioxenoblastic texture (Mineral Science Ltd, 1997).

RESULT AND INTERPRETATION Geochemistry The geochemical anomalous zones correspond with the major apatite bearing lithological units of upper and lower zones and the relatively elevated values of P2O5, represent patches of

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 anomalies corresponding with the lenticular apatite-bearing lenses of hornblendite and hornblende gabbro. Geological mapping has shown that the igneous banding is inward towards the center of the intrusion, and corresponds closely with the swing of the geochemical anomaly. The inference from this is that the apatite mineralization is strata bound (Gallon, 1997).

Fig. 2 Zones of phosphate mineralization of Soji-Bikilal. (Extracted from report no.2. Consult 4 int., October 2001)

Considering combined sections of boreholes and trenches, regardless of the lithotype of the lithological units, the P2O5 assay values of channel and core samples enabled to delineate two main zones of phosphate mineralization (Fig. 2). The 3D-wire frame of the mineralized layers of both zones is outlined, by applying ―Gemcom‖ software as processed by the consultant. The P2O5 assay values were considered and plotted on each section of boreholes and trenches. The subsurface anomalous values of P2O5 were extrapolated and showed two main and one minor layers of phosphate mineralization on the upper zone. The lower layer of the upper zone is identified only on the boreholes sections. Based on surfacial projection of the layer with the calculated dip angle 430 of the upper zone lithology, trench DT2, DT3, DT4 and DT8 were recommended to be extended 60m towards NE and N. The P2O5 assay values of channel samples from these trenches have therefore confirmed the surfacial extension of the lower layer. Accordingly the geological and mineralization map is refined. The strike length of upper zone is measured to be 1600 mt. The thickness of the upper and lower layers of phosphate mineralization is 30m and 40m respectively, separated by a 35m barren zone. Similar interpretation of the data collected from boreholes and trenches of the lower zone reveals that the southeastern part of the zone reaches a thickness of 60m. In the middle of the strike extent, the zone splits into two with the inner layer being up to 100m thick and the outer layer up to 200m thick, separated by 60m barren zone. In the northwestern end the deposit is over 100m thick. The strike length of the lower zone has been measured to be 3000m (Consult 4 International, interim report No2, 2001) (Fig. 2). In the upper zone layers, the phosphate grade over the thickness of the layers is fairly consistent with occassional high grade patches and low grade patches. Overall, the upper and lower layers mean grades of the upper zone are 2.35% P2O5 and 2.62% P2O5 respectively.

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In the lower zone, the phosphate grades are generally higher. The northern part of the lower zone is the best mineralized part of the deposit with phosphate grades averaging 3.7% over a width of 160m (Consult 4 international, interim report No.2, 2001). The main phosphate distribution is normal with an excess of low values. The mean grade of this zone is 2.78% P2O5. Magnetite-ilmenite,Sulphide and Calcite are encountered within the different lithologicalunits.

CONCLUSIONS AND RECOMMENDATIONS As part of the Bikilal layered gabbro-complex, the Soji-Bikilal apatite-bearing zones, in the hornblende gabbro and hornblendite are considered to be promising for igneous phosphate resources. A patite concentrations in igneous complexes are mainly confined to carbonatites, some nepheline – syenite complexes and small alkaline ultramaffic intrusive complexes. Buddington and Lindsley, 1964, Lister, 1966, Philpotts, 1967, and Kolker, 1982, have studied the association of apatite with Fe – Ti oxides among others. All researchers studying the assiciation of Fe – Ti oxides and apatite stated that there seems to be a genetic link between the Fe – Ti oxides and apatite mineralization. Many of the Fe – Ti oxide – apatite mineralization are associated with intrusions of anorthosite, gabbro, pyroxenites, and alkaline rocks. The Soji – Bikilal Fe – Ti – apatite mineralization appears to have many similarities with the known igneous phosphate 9 deposits around the world. For the purpose of comparison, the phalaborwa and schiel igneous complexes of south- Africa are considered and described accordingly. The Soji-Bikilal phosphate deposit is a low-grade and a high tonnage deposit, at which the average grade of phosphate is within a range of 3.0%- 4.0% P2 O5. Regardless of the type of lithological units, entirely based on P2O5 assay values of chip, channel and core samples, two main zones of phosphate mineralization are delineated, namely upper and lower zones. The mineable reserve of Soji Bikilal Phosphate deposit is to be 181 MT, at a grade of 3.5% P2O5. The phalaborwa igneous phosphate deposit is known to be mined since 1930. Apatite has been mined continiously since 1955 by Foskor Ltd. The phosphate ore is extracted from the Loolekop area. The Loolekop body has a carbonatite core which grades outwards into a zone of magnetite – olivine – apatite rich rock called foskorite and then into pyroxenite. The ore reserve exceed 300 Mt at an average grade of 7.45% P2O5 (Notholt et. al., 1990, in Wilson, not dated). The Schiel complex is the largest alkaline plutonic occurrence known in the Northern province of South – Africa. A large deposit of apatite, associated with magnetite and vermiculite, was discovered at Schiel in 1953, and prospected by Foskor between 1965 and 1968. An ore reserve of 36 Mt at 5.1% P2O5 was estimated for the weathered zone to a depth of 39.6m. The average phosphate contents found in the diamond – drill cores found to be 7.4% in the Foskorite, 4% in the Pyroxenite, 4.2% in the carbonatite and 1.6% in the syenite within the ore body, (Wilson not dated).

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Moreover, the Sukulu (Uganda) carbonatite and the Villa-Nora (South - Africa) basic – layered – gabbro complexes are known similar igneous phosphate deposits, at an average grade of 13.1% P2O5 and 6.00% P2O5, with reserves of 130 Mt and 25Mt, respectively (Consult 4 international, 2001). Therefore, the aforementioned information can give a clue about the exploitable grade of phosphate from igneous sources, so that it can be compared with that of Soji – Bikilal phosphate deposit. Similar Gabbros intrusions occur in Western Ethiopia and in East Africa which should be assessed for phosphate potential to develop the fertilizer potential of the East Africa Region.

References Abera Sisay, 1992. Apatite and Magnetite-ilmenite resources of the Bikilal layered gabbro complex, unpublished report Geological Survey of Ethiopia, pp26. Bateman Phosphate Technologies. 2001. Mineral Processing Study, Biklal Phosphate Exploration and pre-feasibility study, 3ed interim report, unpublished report. Beshawured, Efrem 1995. The Geology of Ghimbi-Bikilal area, Unpublished report Geological Survey of Ethiopia. Buddington, A.F. and D.H. Lindsley. 1964. Iron – titanium oxide minerals and synthetic equivalents. Jour. pet. Vol.5 part 2, PP 310 – 357. Consult 4 International, 2001. Interim Report No.1, Bikilal phosphate Project, Unpublished report Consult 4 International. 2001. Interim Report No 2, Bikilal Phosphate Project Unpublished report. Gallon, A. C. 1997. RRM, 5th quarterly report, report no., 4570. Gallon, A. C. 1997. RRM,. Interim report, report no., 4571. Ethio Korean Iron Exploration Project. 1986. Ethio Korean Iron Exploration and Deposit Evaluation in central and Western Wollega, Phase I, Unpublished report, EIGS Ethiopia. Ethio Korean Iron Exploration Project 1988. Ethio Korean Iron Exploration and deposit Evaluation in central and Western Wollega, Phase II, Unpublished report, EIGS Ethiopia. Kolker, A. 1982. Mineralogy and geochemistry of Fe – Ti oxide and apatite (Nelsonite) deposits and evaluation of the liquid immiscibility hypothesis. Econ. Geol. 77 1146- 1158. Lister, G. 1996. The composition and origin of selected iron – titanium deposits. Econ. Geol. 61. 271– 310. Mamo Wondafrash. 1997. Annual progress report on the northern target area of Bikilal igneous phosphate deposit, Unpublished report, Geological Survey of Ethiopia pp20. Mineral Science Ltd., 1997. Petrological Description of Seven-drill core samples, Unpublished report. Philpotts, A.R. 1967. Origin of certain iron – titanium oxide and apatite rocks. Econ. Geol. 62. 303 – 315. RRM - EIGS, 1997. The phosphate Manual, Bikilal Phosphate, Exploration and Prefeasibility Project Report No 4563, unpublished report, Geological Survey of Ethiopia pp128. Sergiuenko, V. N. 1986. Evaluation phosphate resources of Bikilal- gabbro intrusive Unpublished report, Ethiopian Institute of Geological Surveys. Wilson, M.G.C Phosphate, council for Geoscience,not dated.

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Petrology And Geochemistry Of The Dioritic And Granodioritic-Granitic Magma, GQorveh Granitoid Complex (GGC), Sanandaj-Sirjan Zone,Western Iran

Torkian* Ashraf, Sepahi Ali A.

Corresponding author: Department of Geology, Faculty of Science, Bu-Ali Sina University, Hamedan, Iran. E-mail address: [email protected] phone number: 0811-8253467

Abstract The Qorveh Granitoid Complex (QGC), western Iran, was emplaced in a Sanandaj-Sirjan Zone (SSZ) convergent setting which resulted from subduction of Neo-Tethyian oceanic crust below Central Iran. This investigation examines the geochemistry of the QGC. In the metaluminous Eocene–Oligocene Itypecalc-alkaline Qorveh Granitoid Complex, three main units have been identified based on field observations, mineralogical and geochemical characteristics. Mafic intrusions consist of diorites, followed by felsic units that include granodiorites and granites. The diorites are characterized by SiO2 contents 48-54 wt %, low abundances of incompatible elements (Ba, Nb, La and Th) relative to enriched mantle, but consistent with values for average middle crust. In addition, they have Al2O3/(MgO+FeOT) ratios from 0.98 to 1.54 and molar CaO/(MgO+FeOT) ratios from 0.59 to 0.71 and were probably derived from a mafic crustal source. The geochemical features combined with the high volume of the granitoid rocks are inconsistent with an origin via differentiation of mantle-derived basaltic parent magma and assimilation. The granodioritic and the granitic rocks show moderate values of molar Al2O3/(MgO+FeOT) and molar CaO/(MgO+FeOT) suggesting an origin involving dehydration melting of a metagreywacke source. Geochemical data on REEs, Y, Rb and Sr in the latter units indicate that amphibole and plagioclase were the major fractionating phases during magma segregation.

Key words: granitoid complex, felsic magma, mafic crust, metagreywacke, Sanandaj-Sirjan Zone, Iran.

Introduction The problem of the variations in lithology of granitoid batholiths has attracted the interest of researchers for many years, [1-3]. Petrologists consider three possible origins to explain the genesis of granitoids: a crustal origin, a mantle-derived origin, and mixed origin that involves both crustal and mantle derived components [4]. Because crustal and mantle-derived materials have distinct chemical signatures, the resulting granitoids can be distinguished by their compositional features. Some petrologists still consider that most granitoids only derive from the continental crust, therefore, the diversity of granitoid rocks then would result from the various sources that can be melted in the continental crust to form granitic magmas [2-3]. Basaltic magmas provide the heat required for the partial melting of various source rocks, such as amphibolites, either by diffusive or advective heating. Numerous intrusive rocks of various size intrude the Sanandaj-Sirjan Zone (SSZ) [5]. They show large range of variation in rock types, but are dominated by granodiorite-granite with minor amount of mafic bodies. This paper focuses on petrology and geochemistry of the dioritic and granodioritic-granitic plutons Qorveh Granitoid Complex (GGC), the Sanandaj-

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Sirjan Zone, western Iran, as a major plutonic complex in the region. The QGC is a typical Itype granitoid. The present paper describes the field relationships, petrography and wholerock geochemistry of different lithotypes within the QGC; these data are then used for the interpretation of the magma sources and magma-generation processes for various rocks within the complex.

Field Relationships And Petrography The QGC is an elliptical pluton and is a multi-intrusion structure, containing several rocktypes. The main magmatic units are diorites, granodiorites, and granites [6-7] (Fig.1). The observed contact relationships indicate that the QGC may have an origin similar to that of Big Timber stock. The QGC intruded regionally metamorphosed rocks at 38–40 Ma [10]. Diorite unit: The dioritic unit occurs as stocks or small masses within the granodiorite. These rocks consist mainly of plagioclase (45–55%), hornblende (15–20%), quartz (10–15%), alkali-feldspar (3–5%) and biotite (1–8%), with accessory apatite, zircon and opaque minerals. The grain size is largely invariable, showing textures ranging from fine-grained to porphyritic. Plagioclase occurs as zoned euhedral to subhedral laths that are sometimes altered to sericite, clinozoisite, epidote and calcite. Hornblende occurs as green euhedral to subhedral laths, 0.2–1.5 mm in length. Quartz and alkali-feldspar occur interstitially. Granodiorite unit: The granodiorite occurs as an elliptical pluton. Based on modal mineralogy, the rock varies in composition between granodiorite, tonalite and Qtz- Hblmonzonite. These rocks are herein collectively referred to as the granodioritic unit. In general, these rocks are medium to coarse-grained with granular texture and the following simple mineralogy: plagioclase (30–38%), green hornblende (20–25%), alkali-feldspar (15–20%) and quartz (10– 25%). Accessory minerals include apatite, sphene, allanite, zircon and Fe–Ti oxides. Granite unit: The widespread granite unit occurs as a large, NW elongated pluton through the southern part of the study area. Rock types include monzogranites, granites, alkaligranites and minor quartz-syenites. Rocks within the granite unit are generally medium- to coarse- grained, showing granular to porphyritic textures. The unit contains plagioclase, Kfeldspar and quartz, with lesser apatite, allanite, sphene, magnetite and zircon and small amounts biotite ± hornblende. The monzogranites exhibit granophyric textures. Large crystals of quartz and feldspar show deformation features such as undulatory extinction and kinking. K-feldspar occurs as phenocrysts or large anhedral patches, as both orthoclase and microcline.

Geochemistry Sampling And Analytical Methods Nineteen fresh samples from different units were selected for geochemical analyses. Wholerock major and trace element analyses were performed by X-ray fluorescence and ICP-MS techniques in the GeoAnalytical Laboratory of Washington State University (USA). Detection limits range from 0.01 to 0.1 wt%, and 0.1 to 10 ppm for major and trace elements, respectively. Total iron is expressed as FeOT. Data processing was by means of the program Minpet[11]. Major and trace element compositions of the analyzed rocks are given in Table 1.

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Major Elements The samples span a range of SiO2 from about 48 to 76 wt%, including the diorites, granodiorites and granites (Table 1). They plot in the calc-alkaline field on an AFM diagram and all samples have Al2O3/(Na2O+K2O) values > 1, and Al2O3/(Na2O+K2O+CaO) values < 1 plotting as a cluster in the metaluminous field [7]. The results of representative rock analyses are plotted on Harker variation diagrams (Fig. 2). Samples from each unit show poorly defined trends. Major elements show no compositional overlap between different units; the overall trends suggest that the granodioritic and granitic rocks are co-magmatic, whereas the dioritic rocks appear to have originated from a different source or different magmatic processes.

Trace Elements As was observed for the major elements, the felsic units show linear trends and the diorites define a distinct group, clearly shown by their high Ni, Cr, Th, U concentrations suggesting a different source or magmatic process for this unit compared to the felsic rocks. The various rock units are best distinguished on a Rb vs. Sr diagram (. Notably, rocks of the QGC form a continuous trend from high-Sr/low-Rb values (diorites) to low-Sr/high-Rb values (granites) via intermediate values for the granodiorites. In a Ba vs. Sr/Nd diagram, dioritic samples show low-Ba/high-Sr/Nd ratios, whereas all other units are characterized by high-Ba/low- Sr/Nd [6-7]. Chondrite-normalized multi-element variation diagrams are shown in Figure 3. Samples from the felsic units show depletion in Nb, Ti and Ta and enrichment in large ion lithophile elements (LILEs) (Ba, K, Rb and Th). The patterns show a systematic decrease in normalized abundances from LILE (Ba, Rb, K and Th) to HFSEs (Y, Ti and Yb). Chondrite-normalized rare earth element (REE) patterns are shown in Figure 4. All of the samples show light rare earth element (LREE) enrichment relative to heavy REE. The patterns have concave-upward shapes that are most pronounced in the granodioritic and granitic samples. There is systematic increase in (La/Yb) N from the diorites via the granodiorites to the granites, and negative Eu anomalies are most pronounced in the felsic units. The mafic unit shows less fractionated REE patterns [(La/Yb)N = 4–8] and decreasing HREEs with increasing negative Eu anomalies (Eu/Eu*= 0.85–1.03), while the felsic units are characterized by strongly fractionated and relatively fl at HREE patterns [(La/Yb)N = 6–18] with moderate to strongly negative Eu anomalies (Eu/Eu* = 0.44–0.95).

Discussion a) Genesis of the dioritic unit Several mineralogical and geochemical characteristics such as the presence of hornblende, (primary) sphene and magnetite as well as ASI < 1, high content of CaO, Na2O and Sr can be used to infer the I-type affinity [6] of the studied diorites. Chemical characteristics of the diorites suggest an origin involving partial melting of mafic crustal material. The low concentration of incompatible elements (e.g. La, Ba, Nb and Th) rule out the possibility that these rocks were produced by melting of enriched lithospheric mantle. Furthermore, the amount of some trace elements including Ba (100–600 ppm), Th (1–7 ppm), La (10–30 ppm) and Nb (7–19 ppm) (Table 1) is lower than observed in diorites derived from the enriched

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 mantle, but rather consistent with average values of the middle crust (Ba: 400–700 ppm, Th: 6–8 ppm, La: 17–36 ppm and Nb: 6–11 ppm, [13]. Thus, it seems likely that the investigated diorites were derived from a mafic lower crustal source. Several experiments [e.g. [14]; cited in [15] have shown that melting of amphibolite under anhydrous conditions and at relatively low temperatures (880–800 °C) leads to the formation of mafic magma. [16]; cited in [17] documented that basic magmas can supply much of the heat required for the melting of basement rocks. However, this depends on the volume of the mafi c melt. The Al2O3/(MgO + FeOT) and CaO/(MgO + FeOT) ratios obtained for the diorites vary from 0.98 to 1.54 and from 0.59 to 0.71, respectively (Table 1). As is evident from Figure 5, these rocks most likely were derived from partial melting of metabasaltic and/or metatonalitic sources. On this basis, we conclude that the dioritic magmas were probably derived from a mafi c crustal source. b) Genesis of the granodioritic and granitic units Figure 2 demonstrates that both the granodioritic and granitic rocks show little internal compositional variation, and there is almost no compositional overlap between them. In addition, both rock types are characterized by low concentrations of transitional elements (Ni, Cr and V). It is therefore unlikely that the voluminous felsic magmas were generated by the differentiation and assimilation of a mantle-derived basaltic parent magma. The compositional diversity of crustal magmas arises from melting of different source compositions and variations in melting conditions, including H2O content, pressure, temperature, and oxygen fugacity [18-19]. Compositional differences that result from the partial melting of different source rocks such as amphibolites, under variable melting conditions may be characterized in terms of their molar oxide ratios such as K2O/Na2O,Al2O3/(MgO + FeOT) and CaO/(MgO + FeOT). For example, the K2O/Na2O ratios obtained for the granodiorites and granites in the present study range from 0.1–0.8 to 0.4–0.8, and their average Al2O3/(MgO + FeOT) and CaO/(MgO + FeOT) ratios are 6.5 and 1.47, respectively (Table 1). As evident from Figure 9, these rocks were most likely derived from metagreywackes. A signifi cant contribution from metapelitic and meta-igneous felsic magmas can be excluded given that the granodiorites and granites display high molar CaO/(MgO + FeOT) and low molar Al2O3/ (MgO + FeOT) ratios (Fig. 5). The granodiorites and granites are characterized by a general decrease in normalized abundances of elements from Rb to Y (or Yb) (Fig. 3) and concave-upward REE patterns (Fig. 4). This suggests that the amphibole-out boundary was not crossed during partial melting, leaving amphibole as a major restite phase. Compared with the granites, the granodiorites show higher Sr/Nd and Sr concentrations and smaller negative Eu/Eu* anomalies, suggesting a relatively small amount of plagioclase fractionation in the latter.

Conclusion The Qorveh Granitoid Complex (QGC) displays field relations and mineralogical and geochemical characteristics that are typical of calc-alkaline granitoids in the Sanandaj- Sirjan Zone, which presumably developed during subduction of the Arabian plate beneath the continental crust of the Central Iran plate. Field relationships, petrography and whole-rock geochemistry of the different rock units of the QGC indicate that the magmas that produced the dioritic, granodioritic and granitic units had intra-crustal sources. The chemical

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 characteristics of the felsic rocks point toward the partial melting of metagreywackes, whereas the dioritic magma was derived from a lower crustal mafi csource. Further isotopic studies are necessary to better understand the nature of the protoliths.

References 1- Chappell, B.W., and White, A.J.R., 1992, I- and S-type granites in the Lachlan Fold Belt, Transactions of the Royal Society of Edinburgh: Earth Sciences. v. 83, p. 1-26. 2- Altherr, R., Holl, A., Hegner, E., Langer, C., and Kreuzer, H., 2000, High-potassium, calcalkaline, I-type plutonism in the European Variscides: northern Vosges (France) and northern Schwarzwald (Germany), Lithos, v. 50, p. 51-73. 3- Chappell, B.W., and White, A.J.R., 2001, Two contrasting granite types: 25 years later. Australian Journal of Earth Sciences, v. 48, p. 489–499. 4- Pearce, J., 1996, Sources and setting granitic rocks, Episodes, v. 19(4), p. 120-125. 5- Berberian, M., and King, G. C. P., 1981, Towards a Paleogeography and Tectonic Evolution of Iran: Canadian Journal of Earth Science, v. 18, p. 210–265. 6- Torkian, A. Torkian, A., Khalili, M., Sepahi, A.A., 2008, Petrology and geochemistry of the I-type calc-alkaline Qorveh Granitoid Complex, Sanandaj-Sirjan Zone, western Iran, area, Neues Jahrbuch fur Mineralogie Abhandlungen, v. 182 (2), p. 131-142. 7- Torkian, A., 2008, Magmatism investigation of the South-Qorveh Granodiorite intrusive body (Kurdistan), PhD Thesis, Univ. of Isfahan, Iran. 8- Alavi, M., 1994, Tectonics of the Zagros Orogenic belt of Iran: new data and interpretations, Tectonophysics v. 229, p. 211–238. 9- Hosseini, M. 1999, Geological map of Qorveh, Geological Survey of Iran, scale 1:100,000. 10- Bellon, H. and Broud, J., 1975, Donnes nouvelles sur le domaine metamorphique du Zagros (zone de Sanandaj-Sirjan) au niveau de Kermanshah-Hamadan (Iran), Nature, age et interpretation des series metamorphiques et des intrusions, evolution structural, Faculty Sciences de Orsay, Paris. 14. 11- Richard, L. R., 1974, MinPet: Mineralogical and petrological data processing system, version 2.02. MinPet Geological Software, Québec, Canada. 12- Nakamura, N., 1974, Determination REE, Ba, Fe, Mg, Na, and K in carbonaceous and ordinary chondrites, Geochimica et Cosmochimica Acta v. 38, p. 757-775. 13- Sun, S. S., McDonugh, W. F. 1989, Chemical and isotopic systematic of oceanic basalts: implications for mantle composition and processes, in: Saunders, A. D. and Norry, M. J. (editors): Magmatism in ocean basins, Geol. Soc. London. Spec. Pub v. 42, p. 313–345. 14- Wyllie, P. J., and Wolf, M. B., 1993, Amphibolite dehydration melting: sorting out the solidus, in: Prichard, H. M., et al., (editors): Magmatic processes and plate tectonics, Geological Society of Spec Publ. v. 76, p. 405–416. 15- Johannes, W., and Holtz, F., 1996, Petrogenesis and experimental petrology of granitic rocks, Berlin, Springer, Verlag 335. 16- Chapman, D.S., 1986, Thermal gradients in the continental crust. in: Dawson, J.B., Carswell, D.A., Hall, J. and Wedepohl, K.H. (editors), The nature of the lower continental crust, Geological Society Spec. Publi. V. 24, p. 23-34.

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17- Gupta, A. A., 1998, Igneous rocks, Allied publishers limited, India, New Delhi, 690. 18- Wolf, M. B., and Wyllie, J. P., 1994, Dehydration-melting of amphibolite at 10 kbar: the effects of temperature and time, Contributions to Mineralogy and Petrology v. 115, p. 369-383. 19- Patino Douce, A. E., and McCarrty, T. C., 1974, Melting of crustal rocks during continental collision and subduction., In: Geodynamics and geochemistry of ultrahighpressure rocks, Petrology and Structural Geology 10, Kluwer Academic Publishers, Dordrecht p. 27–55.

Fig. 1. Tectonic zones of the Zagros orogen in western Iran (after [8]) and simplified geological map of the Qorveh Granitoid Complex (based on [9]).

Fig. 2. Harker variation diagrams for some of major and trace elements from the QGC. Note that there is a compositional gap between the diorites and the granodiorites-granites.

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Fig.3. Chondrite-normalized multi-element variation diagrams (values given by Thompson et al., 1982: in Richard 1995) for samples from (a) diorites and (b) granites and granodiorites. Symbols are as in Fig. 2.

Fig. 4. Chondrite-normalized REE patterns [12] for (a) diorites(b) granites and granodiorite. Symbols are as in Fig. 2.

Fig. 5. Chemical compositions of different unit: (a) Mg number [Mg# = molar 100*MgO/(MgO + 0.9 FeOT] vs. SiO2. (b) Molar K2O/Na2O vs. Al2O3/(MgO + FeOT) (c) Molar Al2O3/ (MgO + FeOT) vs. molar CaO/(MgO + FeOT). Curves separating the partial melt fields are from [18-19]. The granodioriticand granitic rocks show high ratios of molar Al2O3/(MgO + FeOT)as expected for partial melts derived from metapelitic and metabasaltic–metatonalitic sources but similar to melts derived from metagreywacks sources. Symbols are as in Fig 2.

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"Study of Morphometry factors Regressions of Chalus drainage basin using Statistical methods and mathematical models "

Mousavi harami . R1 , Motamed . A 2 , Ahmadi,h3, Moghimi . A4

1 - Professor of the Department of Geology , Ferdowsi University , Mashad

2 - Professor of the Department of Geology , Islamic Azad University , Sciences and Research Branch , Tehran .

3 - Professor of the Department of Natural Sources , Teharn University , Tehran .

4 -Faculty Member of the Department of Geology, Islamic Azad University , Lahijan Branch , Lahijan and

Ph.D.student in , Islamic Azad University Sciences and Research Branch , Tehran

Abstract In this Study , we try to determine morphometryFactors Regressions of chalus drainage basin by Statitistical functions andmathematical Methods . According to this study , a significant relation was found between Sub-basin areas and the length of drains in the form of linear and non- linear models (Exponential ,Quadriatic and cubic ) . Therefore , the largest drainage area belongs to grade 1 drains , and the Smallestdrainage area belongs to grade 5 and 6 drains Furthermore , using pearson Correlationcoefficient it can be concluded that the Length of grade 3 drains has the most effect onthe density of drain in chalus drainage basin . Regarding the colinearity relations between area and altitude (A= .o18h ) , these two parameters cannot be used as independent Variables in regression models whose dependent variables are density of drain branch ratio (Rb) . The Calculation of drain Frequency (F), Density of drain(D) and determination of the ratio F/D2 in Chalus drainage basin indicates a linear relation (F=.14D2)between the two parameters . Consequently , this basin is in the stage prior to maximum drainage development ,regarding the evolution of drain network .

Keywords : morphometry Variables , regression relations , mathematical models ,Statistical methods , density of drain , regression models , Pearson Correlation coefficient .

Introduction Drainage Basin refers to the area of a region where the runoff resulting from the rainfall in hat region is directed naturally to a single point called they ''point of concentration'' . If the point of Concentration is in the drainage basin , it is called a '' closed basin '' , and if the point of oncecntration is located at the end of drainage basin . where the runoff can go out of the drainage basin ''open basin'' it is called an (Ali zadeh , 1381) . An awareness of the physiographical characteristic of a drainage basin together with the information obtained of the weather conditions of the region can show the quantitative and qualitative Functioning of the hydrological system of that busin( petilik , 1994). In order to assess more accurately and to know the potentials of the drainage basin more, we can divide it into Smaller hydrological units (called sub-basin) and then to study each of them

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(the units ) separately . some of the physiographical and topographical features of a region including the slope and the height can control most of the climatical factors such as the temperature and its changes , the kind and quantity of annual rainfall , and the quantity of evaporation and transpiration , this yields to the formation of different kinds of regional weather conditions ( Gurtz , 2000 , wang et . a1., 2003 , Garsian et. al., 2004) . Therefore, in geomorphological theological studies of a drainage basin , it is necessary to study the physiographical characteristics and morpho metrical factors and also the possible correlations and regressions betwean these factors beforehand .

The geographical positioning The studied region is located in the north of IRAN and north range of middle Alborz 2 and in the south of Caspian sea in the geographical longitude of eastern 500 / 00¢ to eastern 500 /35¢, and in the geographical latitude of northern 360 / 08¢ to northern360 / 43¢ .The drainage basin of chalus river is leading to the drainage basin of Surd a brood river from west, the drainage basin of kurkuresar river from east, the drainage basin of karaj river from south , and the Caspian Sea from north(Figure 1 ).

Materials and Methods In order to study the correlation and regression between morphometrical variables of the drainage basin of chalus river, first we divide it into smaller sub-basin (figure1) .According to this, the Chalus drainage basin is divided into four sub basin as: 1-The sub-basin of Elika-Duna, and kandevan. 2- The sub-basin of Elite –Dalir. 3-The sub-basin of kojur(Hanisk). 4- The Sub-basin of Barar. In the current study, first we will calculate the morphometrical parameters of the basin with the use of Are view and Arc GIS Softwares . (tables1,2,3,4) , and then by means of spss 15 software also we will determine the regressions and correlation between morphometical parameters .

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Discussion 1-The relationship coefficient between the area of the subbasin and the length of river branches. There was a consistent meaningful regressions coefficient of more than 78% on the surface between the area and the variable related to the length of the river branches whereas in large drainage basins, the existence of such regressions between variables is a sign of an increase in the length of total branches of a river in relation to longer branches (Farifte, 1991) . In the drainage basin of chalus, the regressions of the area and the length of drains is meaningful in different degrees on different levels. There fore , for each of the branch , we can present models with the following forms (figures , 2-a , 2-b , 2-c , 2-d , 2-e , 2-f): 1- A Compound model for Grade Drains (channels of first degree )(L1) : ( Ln( A) =1.035 +(L1 )(53/599 ). 2- A linear model for Grade (2) drains (L2) : A= -144/128 +47/645 (L2) 3- A quadratic model for Grade (3) drains (L3): A=- 206/10 + (L3)2× (31,105 ) +(596/65) × L(3) 4- A compound model for Grad (4) drains (L4): Ln (A) =3.376 +2.97 (L4) 5- A cubic Model for Grade (5) drains (L5) : A= 325/22 – (L5) 3 × (844/672) +169 6- A Quadratic model for Grade (6) drains A= 925/787 +(L8)2×(132/203)-(639/615)× (L6) According to the above mentioned models , we can conclude that the relations between the area and the length of different drains either in linear models or in non-linear models is direct, however , the length of gamed (2) drains have the most influences on the area of drains .

2- the relations between the density of drains and the length of drains in sub-basins In order to determine the effects of the length of grade of them , we used the Pearson correlation coefficient(table,5). The results obtained from this method shows that the grade(3) drains have the most effects ( the Linear model ) , and the grade(6) drains have the least effects on the density of drains. (Figures 3-a , 3-b ,3-c , 3-d , 3-e , 3-f) 3- The relation between the dense of drains and height: The regress ional analysis of the two above – mentioned parameters shows the existence of a exponential model with a high reliability (R2 =98%) . We can show this relationship as the following equation. Ln(D)= - % 1H = D=e-%1h In the above equation D Equals the dense of drains and h is the height. Having in mind that in chalus drainage basin there is a reverse relation ship between the dense of drains and the height, and also that most of the area of the basin is drained with grade 1,2,3, and 4 drains (Table, than ). we can conclude that most of the dense of the drains is related to Grade 1,2,3,4 drains ( which are located in the height of 500-3500 meter ) . These deains cause the most amount of erosion which is under the influence of tectonic , impact of the

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 region and less than this under the influence of the Lithology of the drainage basin .(figures 4- a,4-b,4-c,4-d,4-e) 4- The relationship between the area and the height. To explain the relationship between the are and the height, first we should make it clear that whet har the two parameters have a collinear relationship? If there is no collinear relationship, we .can consider them as independent variables in a regressional model in which the independent variables are the dense of drains and branch ratio. Noticing that the area and the height are colinear (with the reliability of R2=0/98 and pv =%4 ) according to the following model : A=%018H Where A is the Area and H is height. These two parameters can not be considered as independent Variables in the mentioned correlation relationships (picture 8 ) . on the other hand , the relationship between the dense of drains and the area and also the relationship between the dense of drains and the height both follow a exponential function . This also is a reason to consider the relationship of the area and height as linear . Moreover, according to Table 2 , Grade 1,2,3,4 and 5 drains drain Larger area of the drainage basin , and Grade 6 drains drain Smaller area of the drainage basin . since most of the Grade 6 drains are located in the height of below 500 meters , we can consider this according to the findings of Doornkamp , 1990 ) due to the effect of factors such as the differentes of lithology , the amount of rain fall , and the different tectonic functioning in different patrs the drainage basin . 5- The relationship between the slop and the grade of the drain . The existence of linear and nonwlinear relationships with high amount of reliablility and low amount of error for the two parameters is according to the following models : 1- The linear model x=n.2/09 2- The non-linear model x=e0/44n X= Tthe slope of the subbasin,n=The Grade of the drain We can mention that the gradual progressive cutting of the drainage basin causes an increase in the averte slope in the length of the valley domain (according to the 5 phases of Gloks, 1970) , this can continue until the fifth phase , then we see a decrease in it (Athanassios et al, 2005) . The above – mentioned point indicates that the Grades 4 , and 5 drains have the most amount of slope , and due to this they have an in fluential role in the process of erosion and flood although they have a less important role in the dense of drains . (figures 5-a,5-b) 6- The relalionship between the frequency of drains (F) and the dense of drains . Since the frequency of drains and the dense of drains are obtained from the following equations ( sham, 1989) :  N F  a Nu= the number of drain A L D   L=The length of drain A L D   A= The area of drainage Aba sin So we can write :

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NN FDFD//uu   L 2 ()L 2 The frequency of drains in a drainage basin has a close relationship with the bed rock (Doornkamp , 1991 ) . The obtained ratio (F/D) for chalus drainage basin is 0.14 (according to the finding of Chorely et at , 1990) , therefore the drainage basin of chalus from the point of evolution of the drain network in the third phase (the phase before the maximum drainage development) (figure 6) .

Results 1- since in chalus drainage basin , Grade -1 drains have the most amount of length , There is drains of the first grade drain more area compared to other drains (with Grades 2,3,4,5,6 ) . 2- Since Grade 3 drains have less frequency compared to other drains (Grade 1,2,4,5,6) ,internal of evolution chalus basin is in the third stage (the stage prior the maximum drainage development . 3- since there is a colinearity relation between the area and the height (withhigh p.value and low percentage of error) . we can not use these two parameters as independent variables in a regressional model whose dependent variables are the density of drain and the ratio of branch (Rb) 4- with the use of pearson correlation coefficient , it is made clear that in chalus drainage basin , the length of Grade 3 drains has the most amount of influence on the density of drain , and the length of Grade 3 drains has the least amount of influence on the density of drain . So in the process of erosion and flooding ,Grade 3 drains are more important ). 5-The colinearity and exponential relations between the slope of the subbasin and the grade of drains indicates that the gradual progressive cutting of the drainage basin causes an increase in the average slope in the domain of the valley. This continued until the third phase of the evolution of the drainage basin . This even can continue until the 5th phase (the beginning of the evolution of the drainage basin too , and then it can follow a decreasing process . 6-The results obtained from the morphometry of the drainage basin indicates that the average length of drain has the highest amount Elit –Dalir Sub-basin , and the least amount Barar sub- basin , Also , the comparison of the length of the drains with the same grade in Sub-basin indicate that grade 1 drains have that highest length , and grade 6 drains have the lowest length . 7- Furthermore, it has been shown that in chalus drainage basin the largest area of the basin which is drained by Grade1 drains belongs to kojur subbasin and the smallest area drained by Grade 1 drains belongs to Barar subbasin . 8- The calculation of the frequency of the drains (F) and the density (D) , also the determinate on of the ratio ofF /D2 in chalus drainage basin indicates a linear relation (F=0.14D2) and shows that this basin is located in the third stages ( the stages prior to maximum drainage development ) regarding the evolution of drain network .

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References 1- Alizade . Amin (1998), "principles of applied hydrology" , 519 p. 2- Athanassios Ganas , Spyros pavlides , vassilios karastathis (2005) , "DEM – Based morphometry of range – front escarpment in Attica , Central Greece , and its relation to fault , Geomorphology , volume 65 , issue 3-4 , pages 301-319 . 3- Chorley , R.j , morgan (1962) , "Comparison of morphometric features unacca mountains , Tennessee and North Carolina Datmoor , England , Geo . Sco . Am . Bul . 73 pages 117-34 . 4- Chorley . J . Richard , schumm . A . Stanley , sudden . E . David (1990), "Geomorphology " , 455 p. 5- Doornkamp , G . A . M. king , Ven te Chow , (1991) , "quantitative Analysis in geomorphology " , 368 p . 6- Garcin . M , poisson , B (2004) . "High rates of geomorphological processes in a tropical area : the Remparts River case study (Re union Island , Indian ocean) , Geomorphology . 7- Goovaerts . p (2000) , "Goeostatistical approaches for incorporating elevation in to the spatial interpolation of rainfall " , Journal of Hydrology 227 , pages 113 – 129 . 8- Maria . jose , Lopez . Garcia , camarasa . M . Ana (1999) , "use of morphological units to improve drainage network extraction from a DEM" , International journal of Applied Earth observation and geoinformation , volume 1 , issues 3-4 , pages 187 – 195. 9- pitlick . J (1994) , "Relation between peak flow , precipitation and physiogeraphy for five mountainous regions in the westen USA , journal of Hydrology , 158 , pages 219-230 . 10. Wang . H . Hall , C . A . S . Scatena , F . N . Fetcher (2003) , "Modeling the spatial and temporal variability in climate and primary productivity across the Luquillo mountains" , Puerto Rico , Forest Ecology and management , 179 , pages 69 – 94 . cxf

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Figure 2 : relationship between area of sub-basins and lenght of drainssssssssss

Figure 3 : relationship between density of drains and lenght of drains

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Figure 4 : relationship between density of drains and elevation

Figure 5 : relationship between slope and grade of drains

Figure 6: relationship between number and density of drains

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The effect of original carbonate mineralogy on diagenetic and porosity evolution in the Kangan Formation, South Pars Field, Persian Gulf

Azadeh.Rahimi*, Mohammad Hossein Adabi, Amir Mohammad Jamali and Seyed Ali.Moalemi

Corresponding author: Islamic azad university, North Branch of Tehran, Basic Sciences Faculty, Iran E-mail address: [email protected]

Abstract The Lower Triassic Kangan Formation is a carbonate-evaporite succession, which is part of the largest carbonate reservoir in the South Pars Field in the Persian Gulf. In this study petrographic investigations, indicate that aragonite was origininal carbonate mineralogy. Based on the abundance of leaching of skeletal grains such as bivalves , gastropods, evaporites & early diagenetic dolomites in the Kangan carbonates are similar to those of modern warm water shallow-marine carbonates. Isopachous and fibrous intragranular sparry calcite cements resemble modern aragonite morphologies. Deformed ooids and spalled ooids indicate aragonite dissolution during meteoric diagenisis. As aragonite is susceptible to dissolution and dolomitization, so the diagenetic processes, especially porosity evolution are very important in enhancement of reservoir quality.

Introduction The Kangan Formation is Early Triassic (Scythian) in age (Motiei, 1993). Kangan carbonates from the South Pars are providing favorable reservoirs for the accumulation of gas. In this study, the thickness of section is about 150m and more than 400 uncovered polished thin sections were studied. Those were stained with alizarin-red S solutions (Dickson, 1965) to identify calcite from dolomite mineralogy. The classification of carbonate rocks followed the nomenclature of Dunham (1962) and Flugle (2004). The aim of this paper is to describe and interpret original carbonate mineralogy of Kangan Formation, based on petrographic studies and the effect on diagenesis and porosity evolution (Adabi & Rao, 1991). On the other hand, the primary morphology and carbonate mineralogy depends primarily on water temperature, similar to observations in modern carbonates. In Recent tropical warm shallow marine carbonates (temperatures >25ºС), meta-stable aragonite is the predominant mineral, with variable amounts of high-Mg calcite (Milliman 1974). Stratigraphy and geologic setting This study deals with Early Triassic Kangan Formation, that is exposed in south west Iran, which is considered as upper part of Dehram Group. The lower contact with the Dalan Formation is disconformable and the upper contact with the Dashtak Formation (Aghar shale member) is conformable (Ghazban, 2007) .The South Pars Filed, one of the important offshore filed in the world, is located on the Iran-Qatar border in the Persian Gulf (Fig.1). The litohlogy of Kangan carbonate is composed mainly of dolomite and limestone with minor amounts of anhydrite. Petrography The Kangan carbonates consist of skeletal and non-skeletal grains, abundant sparry calcite cement, micrite, early and late diagenetic dolomites and minor evaporates (anhydrite). 2

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Skeletal grains Skeletal grains are bivalves, gastropods, claraia, spirorbis, ostracodes and stromatolites. Shells structure of claraia, ostracodes and spirorbis consists of well preserved calcite (HMC- LMC), whereas shells of bivalves and gastropods composed of aragonite are not preserved due to dissolution and precipitation of cement specially, anhydrite or dolomite cements in the Kangan carbonate (Fig.2A). Non-skeletal grains Non-skeletal grains consist of ooids, intraclasts and pellets. In modern marine aragonitic ooids, the concentric structures dominate in high-energy environments, such as platform margin oolitic shoals of the Bahamas and tidal channels and deltas of the Persian Gulf (Loreau and Purser.1973). The tidal channels of Kangan consist mainly of ooids with aragonite mineralogy, therefore deformed ooids structure such as spalled ooids are present (Fig.2B).

Cementation Different generations of sparry calcite cementation are recognized in the Kangan limestones ranging from marine, meteoric to burial cements. Isopachous calcite cement, are first generation cement (Marine cement) in this study. Meteoric equant to mosaic sparry calcite cement and later followed by drusy phreatic cements, which are other cements in the Kangan Formation (Fig.2C, 2D, 2E) .Coarse dolomite (baroque or saddle) and poikilotopic anhydrite are burial cements in the Kangan limestones. In some part of succession, early cements resulted in preservation of primary porosity and even these cements have been replaced by dolomite.

Evaporites Anhydrite and gypsum are common minerals in dolostone reservoirs. Most of the gypsum changed to anhydrite. Anhydrite present in most of the facies and has filed pores such as interparticle, moldic and fenestral pores, thus it called cement (Lucia, 2007). Poikilotopic, pore-filling and nodular (Fig.2F), anhydrite is the most common form of anhydrite in some dolostone.

Dolomitization Two types of dolomite occur in the Kangan Formation. The early diagenetic dolomites are equicrystalline and are mainly confined to unfossiliferous supratidal sediments. The late diagenetic dolomites are inequicrystalline and completely replaced limestones. The replacement of dolomite in Kangan facies is fabric destructive and fabric selective dolomite such as ooids, intraclasts and some of the bioclasts with aragonite mineralogy (Fig.2G). Dolomitization connect voids and increase the permeability.

Dissolution The observations suggest that solution process in carbonate facies lead to creation mold and vuggy pore space (Lucia, 2007). Due to this process on meteoric phase in the Kangan Formation facies, ooid grains and some skeletal (gastropods and some bivalves) have dissolved in grain- dominated facies because their mineralogy are aragonite and so, the

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 moldic porosity is very common (Fig.2H).

Porosity Dissolution has important effect on increasing of porosity and lead to enhancement of reservoir quality. Porosity is mainly secondary (fabric selective and non-fabric selective porosity) such as moldic, vuggy, intergranular and channel porosity in the Kangan Formation (Fig .2I, 2J).The reason for this porosity was aragonite mineralogy of some skeletal and non- skeletal grains in this study. Creation of new pore spaces through this process has increased the porosity, but cementation by calcite it has occluded interparticle pores and permeability of the facies.

Conclusions Result of petrography evidences indicate that aragonite was the predominant primary mineral in the Early Triassic carbonates deposited in the Kangan Formation in South Pars Filed, Persian Gulf. The criteria include the following: a) The mineralogy of gastropods, bivalves and ooids are aragonite. b) Spalled ooids indicative of aragonite dissolution during meteoric diagenesis. c) Isopachous cement is common in modern aragonite deposits. d) Presence of anhydrite cements that has filed pores such as interparticle, moldic and fenestral pores. e) Dolomitization of aragonite bioclasts. f) The oomoldic porosity is very common in the Kangan carbonates.It should be noted that aragonite mineralogy is susceptible to diagenesis and porosity evolution. However, cementation, dolomitiziation and anhydritization had most effect on declining the porosity and permeability, whereas dissolution have caused that reservoir quality improve.

References 1. ADABI, M.H & RAO, C.P 1991. Petrographic & geochemical evidence for original aragonitic mineralogy of Upper Jurassic carbonates, Mozduran Formation, Sarakhs area, Iran: Sedimentary Geology, v, 72p. 253-267. 2. DIKSON, J.A.D., 1965. A modified staining technique for carbonates in thin section. Nature. 205- 587. 3. DUNHAM, R.J., 1962. Classification of carbonate rocks according to depositional texture. In: Ham, W.E. (Ed.), Classification of Carbonate Rocks. American Association of Petroleum Geologists Memoir, v, 1. p. 108-121. 4. FLUGLE, E., 2004. Microfacies of Carbonate Rocks, Analysis, Interpretation & Application. Springer-Verlag, Berlin, Heidelberg, New York. 967 p. 5. GHAZBAN, F., 2007. Petroleum Geology of the Persian Gulf. Tehran University & National Iranian Oil Company. 138-139 6. LOREAU.J.P & PURSER, B, H., 1973. Distribution & ultra-structure of Holocene ooids in the Persian Gulf. In: B.H. PURSER (Editor). The Persian Gulf. Springer-Verlag, Berlin, pp. 279-328. 7. LUCIA, F.J., 2007, Carbonate Reservoir Characterization An Integrated Approach Springer-Verlag, Heidelberg. Second Edition. 366 p. 8. MILLIMAN. J.D., 1974, Marine Carbonates. New York, Springer-Verlag, 375 p.

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9. MOTIEI, H., 1993. Treatise on the geology of Iran: Stratigraphy of Zagros. Geological Survey of Iran, Tehran, 497 p. 10. RAO, C.P. & ADABI, M.H., 1992, Carbonate minerals, major & minor elements & oxygen & carbon isotopes & their variation with water depth in cool, temperate carbonates, western Tasmania, Australia: Marine Geology, v.103, p. 249-272.

Fig. 1. Location map of study area in IRAN

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Fig. 2. Photomicrographs of carbonates from the Kangan Formation. A. Bioclast ooid grainstone. Bivalve is dissolved & mold is filled with dolomite. B. Ooid grainstone. Spalled ooid is showed with red arrow; outer layers are broken whereas the inner ones are intact. C. Ooid grainstone. Isopachous cement around the ooids. D. Meteoric cement. Drusy phreatic cement. E. Burial cement. Saddle dolomite with cloudy appearance is filled vuggy porosity. F. Evaporite. Anhydrite cement with calcite & dolomite. G. Dolomitized intraclast ooid packestone. Fabric selective dolomite (dolomitization of ooid & intraclast). H. Dolomitized ooid grainstone. Oomoldic (moldic porosity). I. Dolostone. Intergranular porosity (red arrows). J. Dolomudstone. Channel porosity.

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Petrography and Mineralogy of Calc Silicates in the Northeast of Golpayegan

Fatemeh Ezadi*, Seyed Mohsen Tabatabei Manesh and Mortaza Sharifi E- Mail address: fatemehesd 65 @ gmail. Com

Abstract The studied region is located in the zone of sanandaj –Sirjan. The zone is originally part of central Iran, and it is as a metamorphic band lengthy along Zagros trust from Orumieh and Sanandaj in northwest to Sirjan and Esfandagheh in Southeast. In petrography studies, the calc silicate rocks include minerals of olivin, pyroxene (ortho- pyroxene, clino- pyroxene), serpentine, termolite, biotite, muscovite, Iron oxide, which have the granoblastic texture and have crystallized and shape in some section olivin distinct sequences of calcium silicates or magnesium silicates progress in quartz dolomites marble which are begun with the talc and then with termolite in the facies of green schist. Also, minerals of talc, termolite, diopside, forsterite are created in these rocks with the increase of degree of metamorphic. Reactions including forming these minerals in calc silicate rocks are talc formation by reaction of dolomitem, quartz and water, termolite formation by reaction of talc, calcite, and quartz , diopside formation by reaction termolit , calcite, and quartz, forsterite formation by reaction of termolit , dolomite, existence illite clay minerals muscovite origin in dolomile marble, that is possible talc in geochemical Analysis. Serpentine is formed by olivine; clino- pyroxene and Iron oxide are formed by olivine. The minerals olivine and pyroxene together in a roch indicate the high temperature of rock formation. Also petrography findings show that the rock has passed two progressive and regressive phases.

Key word: Petrography, Mineralogy, Golpayegan, Calc silicate.

Introduction The studied region is located in Sanandaj- Sirjan and the silicate rocks of this region are located in the Northwest of Isfahan and in the South of Markazi province. About these mentioned stones, It did not study any complete or comprehensive study and in resources like (2, 3), only the rock names have been mentioned. The lime stones of dolomite are the benefit indices to define the alteration because they have a set of calcium, magnet silicates like talk, termolite and diopside which can make in the conditions of pressure, stress and usual temperature (7). The public sequence of minerals categorizing is defined first by Eskola (1922) in dolomite marbles minerals and then Bowen (1940) and Tilley (1951) introduced the importance of talk in the lowest temperature of metamorphism. The mineral sequence in dolomite lime stones which have regional metamorphism is including: Talk (it is not always existed), termolite, diopside or forestrite, diopside + forestrite

Discussion 1. The study method: After field study and sampling with hammer and using of GPS to measure the coordinate of length and width the thin section was provided and they were petrography by using of polarize microscope and by Atlas of metamorphic rocks:

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2. Petrography: The most suitable method to define the lime sediments is that we can categorize then to two grows, one is the marbles which have plenty of carbonates and the other is silicates calc which are without carbonate or little carbonate. The region of mineralization of silicate stones is so invasive because their mineralization is related to the exact mixture of sedimental compounds in first layers. The silicate stones in this region is including of olivine, pyroxene, serpentin, Talk, Biotit (phlogopite) and termolite. Which are including the granoblatic texture (Figer 1). In dolomite stones of silicate, talk is the first mineral which is made according to the reaction of 1(7): 1- 3 CaMg (CO3) 2 + 4SiO2 + H2O → Mg3 [(OH) 2 /Si4O10] + 3CaCO3 + 3 CO2 dolomile quartz water Talk calcite carbon dioxide In the stones of quartz poor, quartz can be used completely via the reaction of (2) and the composite of talk + calcite + termolite will be remained .But in siliceous stones ,the used Talk and the composite of termolite + calcite + Quartz will be made. The find disappearance of talk in these stones can be related to below reaction 2. 5Mg3 [(OH) 2 / Si4O16] + 6CaCO3 + SiO2 → talk 3Ca2 (Mg, Fe) 5 Si7O22 (OH) 2 + 2 H2O + 7CO2 termolite 3. 2Mg3 [(OH) 2 /Si4O10] + 3CaCO3 → Ca2 (Mg, Fe) 5 Si7O22 (OH) 2 + 3Ca Mg (CO3) 2 + CO2 + H2O Diopside and forestrite according to reaction of 4, 5 4. Ca2 (Mg, Fe) 5 Si7O22 (OH) 2 +3CaCO3 + 2 H2O + 2SiO2 → 5Ca (Mg, Fe) 2 Si2O6 +3CO2 + H2O diopside 5. Ca2 (Mg, Fe) 5 Si7O22 (OH) 2 + 11Ca Mg (CO3) 2 → 8Mg 2 SiO4+ 13 CaCO3+ 9 CO2 + H2O forsterite For companionship and symbosis of the minerals of olivine and pyroxe, regard to the presence of their kind is related to (stone composition) and is required to more temperature degree. forestrite is including in the stones poor of silicate or the stones poor of dolomite diopside and forestrite can be symboised only when the connected line of termolite + calcite will be ommited by below reaction. Also the existing of clay minerals and other tainting in dolomite can be caused to system complication and the minerals like Epidote, Muscovite and plagioclase and phlogopite will be appeared in the stones. 6. 3Ca2 (Mg, Fe) 5 Si7O22 (OH) 2 + 11CaCO3 → 11Ca2 (Mg, Fe) 5 Si2O6 + 2Mg 2 SiO4 + CO2 +H2O

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Fig 1. Microscopic images of calc silicates in the north east Golpayegan (50x, XPl)

Conclusion: 1. The existing of olivine, pyroxene is indicating of the progressing alteration phase and the .existing of Iron oxides and serpentine is indicating of unprogressing alteration phase. 2. Existing of minerals like olivine, pyroxene and Termolite is indicating of alterated lime stones the companionship of minerals of olivine and pyroxene in stones is indicating of high temperature degree in stones.

References 1- Sarabi, F., 1373, Metamophic rocks: issues department of Tehran university. 2- Sharifi, M., 1376, Geology & petrology Igneous rocks in the North east of GolpayGan. 3- Movahedi, M., 1388, Petrography and petrology of granitoids in the Oechestan (South Mahallat, Markazi province), p. 155. 4- Bowen, N.L., 1940, Progressive metamorphism of siliceous limestone sand dolomite: Journal of Geology, no 48, p. 225-274. 5- Eskola, p., 1922, on contact phenomena between gneiss and limestone in western Massachusetts: Journal of Geology, no 30, p. 265-294. 6- Tilley, C.E., 1951, A note of progressive metamorphism of siliceous limestone and dolomites 7- Yardly, B. 1994, An Introduction to Metamorphic petrology, (Kananian, A., Ghasemei, H. and Asiabanha, A.): Journal Daneshgahi publications, (Majd), P 411.

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Apatite Chemistry And Its Application To The Hydrothermal Evolution Of The Se-Chahun Magnetite-Apatite Deposit

Zahra Bonyadia, Behzad Mehrabi, Garry J. Davidson, Sebastien Meffre and Fereydoun Ghazban

a Geology Department, Tarbiat Moallem University, Tehran, Iran, [email protected], 09124109039

Abstract Se-Chahun Magnetite-apatite deposit is located in the Bafq , Central Iran. The deposit comprises two major orebodies, anomaly X and XI. The anomalies are located in: 31° , 52´, 30″ N ; 55° , 42´, 07″ E and 31° , 54´, 20″ N ; 55° , 43´, 57″ E respectively. The deposit contains an overall resource of 117.6 Mt of high-grade Fe ore. The Se-Chahun deposit is considered to be an example of a Kiruna-type deposit. The host rocks in both anomalies have undergone widespread Na metasomatism (chessboard albite), followed by Na-Ca metasomatism (amphibole- albite-magnetite-calcite-epidote-quartz-titanite-allanite), mineralization (magnetite-apatite), K- metasomatism (K-feldspar and less amounts of biotite), brecciation and carbonate veining. Sulfide minerals are rarely present in the ore or wallrocks. Where present, they are associated with a paragenetically late calcite-quartz-chlorite-(hematite) assemblage, and are dominated by pyrite with subsidiary chalcopyrite. The earliest mineralization products consisted of semi-massive magnetite intergrown with coarse apatite. High resolution back scattered electron images (BSE) of the coarse apatite grains show some heterogeneous zonation patterns in single apatite grains. The dark and bright zones in Se-Chahun apatite are mainly patchy and irregular. Electron microprobe analysis (EMPA), and laser ablation-inductively coupled plasma-mass spectrometry (LA–ICPMS) techniques were employed to determine the difference between the chemical composition of the bright and dark areas in the apatite. Following the development of magnetite-apatite assemblage, prior to brecciation, K-Cl rich fluids changed most primary apatite (SEM-bright) to SEM-dark apatite by leaching LREE+Y, Na, Cl, Si, S and As and adding Ca and P. Monazite inclusions were produced at this stage in the dark apatite areas. Monazite also formed after apatite brecciation. It is concluded that LREE+Y, P, Ti and Al had restricted mobility in the hydrothermal evolution of the deposit. Other elements such as S, Fe and As had greater mobility in the system. Apatite and magnetite growth appears to have been contemporaneous with the sodic-calcic alteration, but immediately prior to brecciation. This process provides a window into hydrothermal evolution during and after mineralization, that lead immediately to brecciation, presumably driven by larger-scale volatile release.

Keywords: apatite, Se-Chahun, dark, bright, hydrothermal, metasomatism.

Kiruna-type and Fe oxide–Cu(-Au) deposits are considered by [1] to be end members of a continuum of mineralized systems that typically developed in post-Archean tectonic regimes characterized by igneous activity. Se-Chahun and other Fe-oxide-apatite deposits in the Bafq district have various mineralogical and geochemical characteristics that are typical of the Kiruna-type magnetite-apatite end member. The mineralization is hosted by metasomatized (altered) rhyolitic tuffs and intercalated shallow-water sediments, sandstone, dolomitic limestone and shale, which represent the middle sequence of the Saghand Formation [2]. The host rocks in both anomalies were

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 strongly affected by both early sodic (chessboard albite) and pervasive sodic-calcic alteration (amphibole-albite-magnetite–apatite-calcite-epidote-quartz-titanite-allanite). Sodic–calcic alteration is accompanied by magnetite ± apatite formation (in all orebodies) and follows by potassic alteration (in anomaly XI), chloritization, carbonate veining, and hydrolytic alteration. There are two different types of apatite in Se-Chahun iron deposit. The first type consists of small apatite inclusions within the magnetite grains, present in all orebodies of the deposit. Due to the small size of the apatite of this group (less that 40 μ), their chemical analysis was unreliable. The second group is represented by coarse euhedral up to 4 cm long crystals. This group is only observed in anomaly X. High resolution back scattered images of the latter show some heterogeneous zonation patterns in single apatite grains (Figs. 8A and 8B). [3] reported the same feature in apatite from Kirrunavaara magnetite-apatite deposit. The dark and bright zones in apatite are mainly patchy and irregular, but it seems that the development of the dark areas in apatite shows a preferred orientation (i.e. parallel to crystallographic c-axis). The patterns continue through brecciated zones as well, and the cracks and fractures do not have affected on the patterns. Thus it is concluded that the brecciation has occurred afterward (Figs. 8A and 8B). In general, numerous fluid inclusions are scattered in the dark areas. However some dark areas do not include inclusions (Fig. 8B). The frequency of fluid and solid inclusions is much less in bright areas of apatite. Electron microprobe analysis (EMPA), and laser ablation-inductively coupled plasma-mass spectrometry (LA–ICPMS) techniques were employed to determine the difference between the chemical composition of the bright and dark areas in the apatite (Table 1, Fig. 2). The difference between the areas is mainly due to different concentrations of REE and some trace elements, such as Si, Na, Cl and F. Rare earth elements have large atomic weights and produce more back-scattered electrons, hence, apatite with an elevated REE concentration shows a brighter image, while dark domains are depleted in REE. In all samples, Na2O, SiO2, Cl, FeO, SO3 and LREE contents in bright areas are significantly higher than those of dark areas (Table 1). In some samples, the concentration of some elements such as S and La are less than detection limit in dark areas. Monazite inclusions were produced due to the leaching of primary (bright) apatite and producing the dark apatite areas. Monazite formed in the dark apatite zones and in the matrix of the apatite breccias produced as a result of brecciation. It is concluded that LREE+Y, P, Ti and Al had restricted mobility in the hydrothermal evolution of the deposit. Other elements such as S, Fe and As had greater mobility in the system. Apatite and magnetite growth appears to have been contemporaneous with the sodic- calcic alteration, but immediately prior to brecciation. It appears that apatite metasomatism took place when Na-rich and/or Ca bearing fluids responsible for the Na-metasomatism and Na-Ca metasomatism were not active, as they prevent the nucleation of monazite, by stabilizing apatite structure. Apatite metasomatism occured as a result of K-rich fluids circulation in the ore [4] and [5]. The fluids are also responsible for the K- metasomatism in the host rocks.

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References [1] Hitzman, M.W., 2000. Iron oxide-Cu-Au deposits: what, where, when, and why. Pp. 9-25 in: Hydrothermal Iron Oxide Copper-gold & Related Deposits: A Global Perspective (T.M. Porter, editor), 2, PGC Publishing, Adelaide, Australia. [2] Samani, B., 1993. Saghand formation, a riftogenic unit of upper Precambrian in central Iran. Geosciences: Scientific Quarterly Journal of the Geological Survey of Iran, 2, 32-45 (in Farsi with English abstract). [3] Harlov, D.E., Andersson, U.B., Fo¨rster, H.J., Nystro¨m, J.O., Dulski, P. and Broman, C., 2002. Apatite monazite relations in the Kiirunavaara magnetite-apatite ore, northern Sweden. Chemical Geology, 191, 47-72. [4] Giere´, R., 1989. Hydrothermal mobility of Ti, Zr and REE: examples from the Bergell and Adamello contact aureoles (Italy). Terra Nova, 2, 60-67. [5] Harlov , D.E., Wirth, R. and Förster, H.J., 2005. An experimental study of dissolution- reprecipitation in fluorapatite: fluid infiltration and the formation of monazite. Contri to Miner. and Petro., 150, 268-286. Table 1: Trace element concentration (wt %) in bright and dark parts of the apatites of anomaly X, measured by EPMA technique.

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Figure 1: Back-scattered electron images showing: (A) coarse apatite grains in a brecciated matrix. The apatite grains show the patchy zonation. Note the extended pattern through the breccias. It shows the priority of dark-bright pattern to the brecciation. The white spots are monazite crystals; (B) The development of dark-bright pattern in the apatite, parallel to crystallographic c-axis. The elongated monazite inclusions have formed in the same direction. The monazite crystals in the brecciated areas are mostly different in shape.

Figure 2: Chondrite normalized REE distribution patterns of dark and bright areas of apatite from Se- Chahun ore deposit, anomaly X. The pattern shows negative anomalies in Eu and slight positive anomaly in Ce. Note the lower concentration of the dark areas (40-50, 50-55) in both diagrams.

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Introducing of Echinoids of the Gurpi Formation, Seimareh Member, Ilam province, Iran

B. Balmaki1, S.A. Babazadeh1, M.Vahidinia2, M. Asgharian rostami2

1. Faculty of Science, Department of Geology, Payame Noor university of Tehran, Tehran, Iran

2. Faculty of Science, Department of Geology, Ferdowsi University of Mashhad, Mashhad, Iran E-mail:Behnaz [email protected]

Abstract The Gurpi formation in Zarin abad section, south of Ilam, consists of 220m Marl with intercalations of Limy marl with two formal members of Seimareh (Lopha) and Emam-Hasan. The mentioned section is situated in the west of this road (E 46°, 486, 31˝.8 and N 32°, 566, 13˝).The formation was deposited from Middle Campanian through Late Paleocene (Selandian) according to the Planktonic foraminifera recorded. At this study in order to detailed study of Echinoids, some samples are collected from Brown limestone member of Seimare from Gurpi Formation. Paleontological results indicated Campanian -Maastrichtian age at Seymareh member. Detailed analyses of this member led to recognition of Bivalve especially Bivalve of Lopha, Brachiopods and five Species of Echinoids such as: Salenia nutrix, Globator bleicheri, Orthopsis miliarisi, Goniopygus superbus, Conulus douville.

Keywords: Campanian- Maastrichtian, Echinoids, Gurpi Formation

Introduction The Gurpi Formation & Shiranish (in Iran & Iraq) Aroma and Simsima (in Kuwait, Saudi Arabia and Arab Emirates and Oman) were deposited from Santonian to Danian (89-60.9, million years ago), (Ziegler, 2001). In the time of the collision of Arabian plate with Eurasia, the trench was formed in the North end of Arabic plate, hilled rapidly by the small grains of deep sea areas sediments, which includes excessive amount of planktonic Foraminifera.

Geological position and access ways Some samples of Echinoids were collected during field expeditions and come from Seimare member expansion. The access ways and Location map of the studied area are shown in Fig1. Best access way to this area is the Zarin Abad city and then Tooh Tagh village along the 55 KM of Dehloran to Mehran road (Figure 1), the mentioned section is situated in the west of this road (E 46◦, 48′, 31.8″ and N 32◦, 56′, and 13″). The thickness of succession examined is 213 meter of dark grey marls with intercalation of light grey calcareous marl. Seimare member (Lofa) is defined by yellow limeston. Imam Hasan member includes a cream clay limestone. The age of the Gurpi Formation is determined on the base of planktonic Foraminifara and indicates middle Campanian to late Paleocene (Figure 2)

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Discussion Echinoids are the sea invertebrate groups which now a days can be found in the most sea, are habitat from pole to equator, from sea shore to the depth of 5000 m. 800 species of Echinoids were searched and recognized so far , which are in the age of 450 million year, from the end of Ordovician till now (Smith et al., 1995) all the Echinoids are formed by chitin surfaces which are located in tests and structure, they are Concorde with living in distinction habitats and the relation between skeleton structure and their habitat is recognized. Echinoid is carry to a count as a perfect group to utilize as a paleoenvironmental index. In the formal calcareous part of Seimare from the Gurpi Formation which is prominent as a Lofa limestone, about 5 Echinoids species ere recognized (Plate 1) the type section of this part is in the lorestan province in a place which Seimare river cuts the east – north of Plangane anticline. Here it‘s necessary to consider the structure morphology, point to biometry searching.

Echinoids occurrences: Globator bleicheri (Gauthier, 1889) The species was first described from the late Cretaceous (late campanian) of the Gurpi Formation. Diagnosis: An oval, rather depressed globator with a large, strongly ellipsoidal peristome. The periproct lies high on the posterior surface and is visible from above but not from below. Test range from 9 to 35 mm in length and are oval in outline and profile. Test width is 82- 91% of test length with the widest point on the test coincidental with the posterior portion of the anterior ambulacra. Test height is 61-80%of test length and the tallest point on the test is sub central. Tests in profile have a relatively broad, flat apex and base and a rounded ambitus. Ambulacra are uniserial and pore-pairs are undifferentiated. Above the ambitus they are very strictly uniserial but towards the peristome they become weakly arcuate and reduce in pore- diameter size. The apical disc is more or less central and is tetra basal. Genital plate 2 is considerably larger than the other four genital plates and is covered in Madrepores. Genital plate 3 is the smallest and in the great majority of specimens is separated from genital plate 4 by ocular plate 4, which abuts genital plate 2. Genital plates 3 and 4 are found in contact only is small individuals. The posterior pair of genital plates is in contact posterior to genital plate . Ocular plates are pentagonal in outline and project (Figure 6).

Conulus douvillei (Cotteau & Gauthier, 1895) Diagnosis: a species of Conulus with a rounded to strongly fusiform peristome which is not sunken. periproct situated relatively low on the posterior surface, not visible from above. Pore- pairs adorably arranged triserially. These range from 17 to 45 mm in length and are ovoid to rounded pentagonal in outline. Test width is 82-96% of test length and the widest point coincides with the posterior part of the anterio-lateral ambulacra. Test height is 64-81% of test length and in profile the test has a broad, flat base and is rounded sub conical above. Ambulacra are straight and compound in the pyrinoid style. Above the ambitus pore-pairs are strictly uniserial, but below the ambitus they become offset into three discrete columns and these continue to the peristome edge.

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Apical disc with genital plates 3 and 4 always in contact. Genital plate 2 abuts the other three genital plates but never reaches ocular plate 4 to separate genital plates 3 and 4 genital plates 4 and 1 are always in contact behind the madreporite (Smith, 1995) (Figure 6).

Salenia nutrix Gray, 1835 Description: Test range in diameter from 7 to 26 mm. the test is thus rather inflated in profile and in some specimen almost sub globular. The apical disc is rather flat and only rises very slightly toward the apex. It is subcircular in outline. The suranal plate is relatively large, on average about 25% of the apical disc diameter. It is similar in size to the genital plates. The periproct is approximately the same size as the suranal plate, or very slightly larger, being on average 27% of the apical disc diameter. Approximately half of the specimens have the ocular plate insert. There is a slight elevation toward the periproct edge, but no true rim is developed. All plates are smooth and unornamented. The sutures are usually incised and may have a series of small pits along their length. The ocular/genital plate boundaries always have pits that are more prominent than the rest. Gonopores are present on genital plates from approximately 10 mm diameter. In some specimen ocular 1 is strongly exerts and forms the posterior wall of the periproct, but in other specimens ocular 1 is insert and separated from the periproct (Smith, 1995) (Figure 5) .

Orthopsis miliaris (d Archiac, 1835) Description: Test range from 20 mm to 48 mm in diameter and are circular in outline and bun- shaped in profile. Test height is 39-59% of test diameter and in profile the ambitus lies about one third the height above the base. Plating is trigeminate throughout and pore-pairs are arranged either uniserially or in very weak arcs of three. All ambulacral elements are narrow and elongate and reach the perradius. A primary tubercle (perforate and non-crenulate) straddles two of the three elements in each compound plate. The third element carries two small secondary tubercles and an intermediate row of military granules. Adorally only the first five or sp pore-pairs are offset to form a weak phyllode. There are 55 pore-pairs in a column at 20 mm test diameter, rising to around 90 at 46-48 mm diameter. The apical disc is dicyclic, though occasionally one of the posterior oculars may just be exerts. Genital plates are broad and crescentic in outline, except for the madreporites, which is larger and more pentagonal in outline. Madrepores occupy almost the entire surface of the madreporite plate and there are small scattered tubercles amongst the openings. Gonopores are present even in the 20 mm diameter individual. Ocular plates are small and pentagonal. All plates have small secondary tubercles, those on the genital plates tending to form a circle around the periproct. The periproct is irregularly oval in outline and occupies 10-14% of the test diameter (Smith, 1995) (Figure 4).

Goniopygus superbus Diagnosis: A species of goniopygus with relatively narrow ambulacra with a single small secondary tubercle on each compound plate a trigonal periproct with predominantly, three perianal tubercles and apical disc plating that is smooth and unornamented. Gonopores lie on the genital plates.

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Test range in size from 25 to 41 mm in diameter and are circular in outline. The preproct is oval and lies slightly posterior of centre. It is approximately 9-21% of the test diameter in width along the approximately 9-12% of the test diameter in width along the anteriorposterior axis. In the great majority of specimens the opening is trigonal and there are three perianal tubercles on genital plates. The apical disc is flat, large and prominent. It occupies 35-43% of the test diameter. Genital plates are pointed distally and the gonopore opens beyond the tip of the apical disc platform, though still within the genital plate. Ocular plates are relatively large and are inserting. All plates are flat and smooth, without ornamentation (Smith, 1995).

In Figure 2 the ratio of diameter to high is distinguished in 5 species and it is shown in calcareous part of Seimare belonged to the Gurpi Formation. Using this diagram the systematic searching of astrictive test would be analyzes better .in addition to this diagram the abundance of this 5 specie was probed in this formation (Figure 3).

Conclusion The Gurpi Formation in this section includes 213m thickness and Calcareous member of seimare consist of Brown limestone with the age of Campanian- maastrichtian age. Based on foraminifera assemblages. Some Echinoids were selected for detailed study and five species with Campanian-maastrichtian age recognized that as follow: Salenia nutrix, Globator bleicheri، Orthopsis miliarisi, Goniopygus superbus, Conulus douville Acknowledgments Wish to thank Vahid saadat , for editing this paper.

Refrence Agassiz, L. 1838. Monographie d echinoderms vivans et fossils. Remiere monographie: Des Salenies. 32 pp., 5 pls. Neuchatel. Archiac, A.d. 1835. Formation cretace du sud- Ouest de la France. Memoires de la Societe geologique de France, serie 1, 2: 157-192, pls 11-13 Gray, J.E 1835. On the genera distinguishable in Echinus. Proceedings of the Zoological Society, London, 3: 57-60.

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Clus, C. F.W. 1876. Grundzuge der Zoologie. 4th edition, volume 2, 522pp. Mortensen, T. 1942. New Echinoidea. Videnskabelige Meddelelser fra Dansk Naturhistorisk Forening I Kjobenhaven, 106:225 Duncan, P.M. 1889. A revision of the genera and great groups of the Echinoidea. Journal of the Linnean Society, 23:1-311. Cotteau, G. 1864. Paleontologue francaise; Terrain Crtace, 7 (Echinides). V. Masson, Paris. 892 pp., Atlas pls 1007-1204 Cotteau, G. and Gauthier, V. 1895. Mission scientifique en Persw par J. De Morgan, tome III. Etudes geologiques partie I . Paleontologie; ehinides fossils. E leroux, Paris, 142 pp., 16 pls. Gregory, j. w. 1900. The echinoidea. In, E.R. Lankester (ed), A treatise on Zoology. Part III, the chinodermata, pp. 282-332. A. & C. Black, London. Lambert, J. 1911. Dscription des Echinides cretaces de la elgique 2. Echinides de I etage Senonian Memoires du Musee Royale d Histoire Naturelle de Belgique, 4; 1-81. pls 1-3. Leske, N. G. 1778. Jacobi Theodori klein nuturalis disposition Echinodermatum. Addimenta ad kleinii dispositionem Echinodermatum. Lipsis, officina Gleditschiana. 279 pp., 54 pls. Meysam Hemmati Nasab, 2008, Microbiostratigraphy and Sequence Stratigraphy of the Gurpi Formation in Kaaver Section, South of Kabir-kuh,Payan name university of Tehran. Smith, A.B. and Wright, C.W.1993. British Cretaceous chinoids. Part 3, Stirodonta, part 2. Monographs of the Palaeontographical Society, London, Publication number 593, part of volume 147 for 1993. Smith A.B, N.J. Morris and A.S Gale, (1995). Late Cetaceous carbonate platform faunas of the United Arab Emirates- man border region, bulletin of the Natural History Museum, volume 51, number 2 Ziegler, M.A., (2001). Late Permian to Holocene Paleofacies Evolution of the Arabian Plate and its Hydrocarbon Occurrences; GeoArabia 6(3): 445-504.

Figure1. Location map of the sequences studied area in the Ilam Province, southwestern Iran.

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Figure2: The distinguished proportional abundance of 5 species in vicinity.

Figure3: The changes diagram of diameter ratio to height is distinguished in 5 species

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Plate1: scale bar = 2cm 1) Globator blicheri 2) Salenia nutrix 3) Orthopsis miliaris 4) Conulos douvillei 5) Goniopygus superbus

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Figure 4- 1, Ortopsis miliaris . A: Apical disc B: Adoral ambulacral plate compounding C: Ambital interambulacral plates,interradius to the left D: apical disc plating-scale bars = 1mm 2, Salenia nutrix A-E: apical discsof nutrix Peron & Gauthier - G-H: ambital ambulacral plating of Salenia nutrix Peron &Gauthier 3, Globator and Conulus A, B F-I G. bleicheri (Thomas & Gauthier) . A: apical ambulacral plating B: adoral ambulacral plating peristomial margin at base F: apical disc G: apical disc H: apical disc I: peristomial plating. C-E Conulus douvillei ( Cotteau & Gauthier). Scale bars = 1mm. 4, Goniopygus superbus C.F: apical disc plating and ambital ambulacral tuberculation of Goniopygus superbus Cotteau & Gauthier.

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In-Situ Monitoring Of Cracks Affecting The Madara Horseman Historical Rock Monument, Northeastern Bulgaria

Nikolai Dobrev

Dept. of Geohazards, Geological Institute, Bulgarian Academy of Sciences, Acad. Georgi Bonchev str. bl. 24, Sofia, Bulgaria, tel.: +359-2-9792292, e-mail: [email protected]

Abstract The rock bas-relief Madara Horseman is carved into limy sandstone on the main rockwall of the Madara Plateau in the 8th Century AC. The monument is included in the World Heritage List of UNESCO. The monument was subjected to the destructive effects of various natural processes throughout its 12 centuries of history, namely weathering, erosion, cracking, creep, and rocktoppling. This requires urgent action for the selection of measures for strengthening and preservation of the monument. Due to the delicate balance of the rocky slope, bearing the bas-relief, the choice of such measures should be clarified very carefully after a thorough analysis of the processes developing in the rock massif. For this reason the precise in-situ monitoring system has been installed to monitor movements of rock blocks around the monument and at the edge of the plateau. Up to present, the results show slow movements in the cracks around the monument with a rate about 0.05 mm/year. However, the movements detected at the plateau edge show large motion of the rock slices separated from the rock massif – more than 0.8 mm/year strike slipping and subsidence. It is also established that movements at the edge of the plateau are strongly influenced by regional and local earthquakes.

1. Introduction The Madara Horseman is a historical bas-relief carved on the NW rock scarp of Madara Plateau. It is situated about 10 km E from the town of Shumen, NE Bulgaria. The bas-relief was created in 8th Century AC during the rule of the First Bulgarian State. It is sculpted in a place where different cultures are combined from different periods - the Thracian, Roman and Byzantine. The rock composition represents a scene of a horseman, who is said to be Bulgarian Khan Tervel (701-717) on his horse, piercing a lion with a spear and followed by a dog (Fig. 1). The monument is cut to a rock scarp at height of 23 m above the terrain and including cut inscriptions is 7.2 m wide, and 6.5 m high. There are Greek inscriptions from various Khans, ruled Bulgaria during this period. This is the only rock bas-relief of the early Middle Ages in Europe. The monument is included in the World Heritage List of UNESCO.

Fig. 1. The Madara Horseman bas-relief with the location of the main cracks and the dangerous rock "flake"

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In its present form, the bas-relief has survived for 12 centuries, but with significant deteriora-tion. Nowadays, there is a disappeared pigmentation, missing parts of the inscriptions, damaged surface (such as certain parts of the horseman are unclear), and three vertical cracks cut through the rock composition. Two of these cracks (no. 2 and 3) divide a thin rock "flake" that creates the main danger for the bas-relief. Due to the delicate balance of the rocky slope, bearing the bas-relief, the choice of protective measures should be clarified very carefully after a thorough analysis of the processes developing into the rock massif. To preserve this monument, various studies were conducted in recent years to identify these processes and to take appropriate decisions for countermeasures. 2. Geological setting The Northwestern part of the Madara plateau is characterized by 80-120 m vertical scarp, and with a 1 km strip of slope deposits dipping from 10 to 20° (Fig. 2). Morphology of the slope is determined by a two layer model of its structure (Fig. 3). The rock massif consists of two complexes [1, 2]: the upper one comprises limy-sandy sediments of Upper Cretaceous – Cenomanian age; the lower one is marly of the Lower Cretaceous – Hauterivian age. There are no sharp lithologic boundaries between the individual units. Yet, it can be recognised that individual layers are characteristic of either high or low carbonate contents, which will result in variation of physico-mechanical rock properties. This variation is highly reflected in all strength properties of this rock [2]. The bas-relief has been carved out of yellowish limy sandstones found between 17 and 100 m. The second lower complex is marly, and consists of grey-bluish layered marlstones, creeping if heavily loaded. Between the Hauterivian and Cenomanian complexes a layer of yellow plastic montmorillonite clay has been discovered. Due to gravitational unloading of the plateau massif, rock slices (lamellae) are divided from the plateau. The height of the slices is about 100 m, but its width is barely 3 m. The fissures reach the plastic clay layer, in which they sink. Unstable substrate involves a wide range of fluctuations, especially in their upper parts, where the amplitudes are larger. As a result, they are increasingly moving away from the massif, with increased inclination towards the slope, with subsequent overturning.

Fig. 2. Geomorphological map of the research area [3]: 1 – alluvial deposits; 2 – gully; 3 – alluvial fan; 4 – creeping deposits; 5 – fault; 6 – plateau edge; 7 – Madara Horseman locality

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Fig. 3. Engineering-geological profile of Madara Plateau [2]: 1 – slope deposits; 2 –sandy limestone; 3 – limy sandstone; 4 – con-glomerated limestone; 5 – clay; 6 – marl; 7 – groundwater table; 8 – 3D monitoring site

3. Monitoring Main purpose of the instrumental monitoring is to obtain real values of the movements occurring in the plateau and the slope below it. This will help to understand the dynamics of the processes, factors that influence these processes and to take right decisions for the preservation of bas-relief. Due to this reason, engineering geological surveys were made in 1990 in the area around the monument [2, 4]. During these studies, an in-situ monitoring system was created. The observation is located at two sites: 1) around the bas-relief, and 2) at the edge of the plateau just above the monument. The monitoring system includes the use of 3D extensometers and minor shifts. The 3D instrumentation includes the TM71 crack gauge, which is designed especially to monitor the micro-displacements along cracks (Fig. 4) [5]. The gauge works of mechano-optical principle of interference, which records displacement as a fringe pattern on superposed optical grids mechanically connected with the opposite walls or crack faces. Practically, it means that values recorded during periods of decades can be well compared. Results will then be provided as displacements on structural planes in mm, and time trends derived as rates in mm per year. Sensitivity of the system is 0.05 to 0.0125 mm in all the three space coordinates of displacement. The meaning of three spatial axes is as follows: X means extension or compression of the monitored crack; Y means horizontal slipping long the crack; Z means a vertical movement. Generally, the crack gauges are to be mounted on steel holders made of thick wall tubes and cemented to drill holes. The holders bridge the fracture with the gauge attached to the holders permanently.

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Fig. 4. A view of 3D extensometer site M8 below the bas-relief

3.1. Monitoring on cracks around bas-relief Two 3D extensometer points (M8 and M10 arranged at crack no. 2) and five shift points observe the movements. Here the measurements show large variations at the X axes due to the seasonal temperature fluctuations (Fig. 5). However, the long-term observations identified a clear trend in the processes in the front part of the rock scarp. The trend of movement of rock flake outside the massif ("flaking") is revealed clearly [6]. The obtained rate is 0.05 mm per year. The subsidence of the rock flake is calculated as 0.03 mm per year. 3.2. Monitoring at the edge of the plateau Five monitoring points control it. One extensometer point (called M9) is installed in a wide fissure between two rock slices just below the plateau main edge. Later (in 2008), the minor shifts were installed in other cracks in that area. The objective of use of these minor shifts is to control the separation process of the new slice behind the main edge of the plateau just above the bas-relief composition.

Fig. 5. Diagram of displacements established at monitoring point M8 for the period 1990-2009: +X – compression of the crack; +Y – the rock flake moving inside the massif; +Z – the rock flake uprising

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The results of the measurements at the edge of the plateau show continuous slip movement of the rock slice at a speed of 0.85 mm per year towards SSE (Fig. 6). The vertical movements of the slice are characterized with subsiding with 0.8 mm per year during the period 1990-1999, and a relatively stable state from 1999 up to present. Movements along the X-axis show both periods of opening and closing the fissure. For the past 10 years, a clear trend of compression of the crack has been recorded. This is confirmed by the shifts behind the plateau edge. This process of compression could be explained as a formation of a new rock slice. The acceleration of the process started in 1999 as an influence of the August 17, 1999 Izmit Earthquake, Turkey (M=7.4). Meanwhile, the obtained results by the shifts confirmed mutual horizontal slipping along the crack to SSE, as the 3D monitoring site M9 already found it.

Fig. 6. Diagram of displacements established at monitoring point M9 for the period 1990-2009: +X – compression of the crack; +Y – the rock slice to SSE; +Z – uprising of the rock slice

4. Influence of seismicity Until the present, effects of earthquakes on micro-displacements along the cracks at the bas- relief have not been established. However, such effects were detected at the upper parts of the plateau. There are large variations, mainly related to the compression and extension of the cracks, but also with slight acceleration movements on the other axes (subsidence and slip to the south). Local earthquakes occur mainly at two source zones, namely Provadia (20 km E) and Shabla-Kaliakra (100 km ENE). Only part of these events influences the movements, mainly from Provadia source zone [4]. The largest effects were established after the earthquakes in Vrancea, Romania, from May 30-31, 1990 (M=6.8 and 6.3), and the second one – with a higher-value after the Izmit Earthquake, Turkey. The monitoring point M9 recorded sharp displacements as the following: ΔX = +6.91 mm compression of the fissure; ΔY = +46.78 mm horizontal slip to SSE; ΔZ = +10.43 mm vertical movement (uprising) of the rock slice (i.e. sharp subsiding of a new-formed slice behind the plateau edge).

5. Conclusions The long-term monitoring succeeded to establish the main trends of movements of rock units tat the bas-relief and the plateau edge above it. Despite the successful results, other questions still remain unclear: 1) the impact of soil creep on the stability of rock slope, and 2) the

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References 1-Venkov, V., Kossev, N., 1974, Studying on the rocks in the range of the Madara Horseman monument envisaging its conservation: Proc. ―Investigation and conservation of the cultural monuments in Bulgaria‖, Sofia: p. 83-97 (in Bulgarian). 2-Frangov, G., Ivanov, P., Dobrev, N., Iliev, I., 1992, Stability problems of the rock monu-ment "Madara horseman": Proc. of the 7th Int. Cong. on Deterioration and Conservation of Stone, Lisboa, Portugal, p. 1425-1435. 3-Angelova, D., 1995, Neotectonics and geodynamics of the Madara Plateau: Problems of Geography, Bulg. Acad. of Sci., v. 2, p. 75-85 (in Bulgarian). 4- Košt‘ák, B., Dobrev, N., Zika, P., and Ivanov, P., 1998, Joint monitoring on a rock face bearing an historical bas-relief: Quarterly Journal of Engineering Geology, v. 30(1), p. 37-46. 5-Košt‘ák, B., 1991, Combined indicator using moiré technique: In Proc. of the 3rd Int. Symp. on Field Measurements in Geomechanics, Oslo, Balkema, p. 53-60. 6-Dobrev, N., and Avramova-Tacheva, E., 1997, Analysis and prognostication of monitored rock deformations: Proc. IAEG Conference, Athens 1997, Balkema, Rotterdam, p. 613-618.

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Biostratigraphy and determining the paleosalinity Upper Maastrichtian based on Echinocorys and Planktonic Foraminifera at Jorband section, Central Alborz, Iran

B. Balmaki1, S.A. Babazadeh11, M. Asgharian rostami2, M.Vahidinia2

1. Faculty of Science, Department of Geology, Payame Noor university of Tehran, Tehran, Iran

2. Faculty of Science, Department of Geology, Ferdowsi University of Mashhad, Mashhad, Iran E-mail: Behnaz [email protected] Abstract Jorband section is located in the north slope of Central Alborz, and 28 Km in South of Noor. With geographic characteristics of 36° 20˝ 32́ and 52° 32˝ 20́. It has been sampled and index fossilic groups of Planktonic foraminifera and Echinoids were studied in order to assign the paleosalinity and biozonation in Central Alborz. Studying of Planktonic foraminifera in Upper Maastrichtian Ziarat- Kola section determining three biozone of 1; Contusotruncana contusa Interval zone, 2:Planoglobulina brazoensis Partial range zone, 3- Racemiguembelina fructicosa Interval zone. Based on this biozonasion determinig Maastrichtian age. In this section the Echinocorys genuses which are vulnerable in salinity changes, were studied in order to determining the salinity mount. Generally Echinocorys have a vice versa connection with salinity, and their amount will increase by decreasing the salinity. In three layers in Jorband section examination Echinocorys genus and is drawn as a diagram which in middle of the section, the salinity mounts is fewer than the beginning and top of the section.

Key word: Paleosalinity, Biozonation, Echinocorys, Central Alborz

Introduction Planktonic foraminifera are one of the most prominent index microfossils to biozonation, because of abundance, Great variety, wide spreading and rapidly evolution in upper cretaceous.Meantime, Planktonic foraminifera are the most important fossilic groups in order to searching and interpreting the paleoenvironments. Echinoids also are the best groups to annotate the paleoenvironment especially salinity (Wisshak and Neumann, 2006). In this research the biostratigraphy and salinity was searched by planktonic foraminifera and echinoids. In order to Jorband section was selected do the searches in central Alborz. In Jorband section the echinocorys genuses which are vulnerable in salinity changes, were studied in order to determining the salinity mount. At all echinocorys have a vice versa connection with salinity, and their amount will increase by decreasing the salinity (Stephens & Virkar 1966). In this section the salinity amount will increase then it will decrease, and finally it will increase again, that this salinity vacillation is confirmed with due attention to the physiologic changes of echinocorys body in regulating of osmotic pressure.

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Location, lithology and Procedures Jorband section is located in the north slope of Central Alborz, and 28 Km in south of Noor, Fig 1). The section of the) ׳ 32 ״ and 52° 20 ׳ 32 ״ with geographic characteristics of 36° 20 study belong to upper maastrichtian and has a thickness has about 15m, includes marl. A total of 35 samples were collected from the section, which were soaked in water with diluted hydrogen peroxide, washed through 63μm, 150μm and 250μm sieves, and dried until clean foraminiferal residues were recovered. About 200-300 individuals were picked up for each sample in two size fractions (63-150μm and >150μm) and mounted on dark cardboard slides for identification..At last to separating the sediments from microfossils, the sample were in ultrasonic machine for 15 minute and they were washed again and finally, the remain sample were studied binocular microscope. The metallurgy research center has prepared SEM photographs from the chosen samples. These two size fractions were analyzed in order to obtain statistically significant representatives of the small and large groups In order to recognizing the planktonic foraminifera it is used from valid resources such as (Caron, 1985, Robaszynski et al, 1995- 1984, Nederbraght, 1991) .

Discussion A: Biostratigrapy An exactly zonation for upper cretaceous is presented by Li et al( Li and Keller 1998a) and Li and others ( Li at al , 1999) and it is used as a base for many of later studied like the studies in Tunisia (Li and Keller 1998b , Abromovich et al 2002) , and Bulgaria (Adatte et al , 2002) in this zonation upper maastrichtian is divided in to eight biozones that in Jorband section 3 zones of Contusotruncana contusa, planoglobulina brazoensis and Racemiguemblina fructicosa, were recognized out of these biozones(Fig2). 1. Contusotruncana contusa partial range zone of Li et al , 1998a: The Rosita contusa or CF6 Zone is defined by the FA of the nominate taxon at the base and the LA of Globotruncana linneiana at the top. This zone is equal with CF6 zone of li and Keller (Li et al, 1998) and has 2m Thickness in Jorband section and it is age is equal with earlir maastrchtian, 2. Planoglobulina brazoensis partial range zone The Planoglobulina brazoensis or Cf5 Zone is defined by the LA of the nominate taxon Globotruncana linneiana at the base and the FA of Racemiguembelina fructicosa at the top. This zone is equal with Pseudotextularia intermedia zone of (Li and Keller 1998a) and (Li et al, 1999) these scientist belive that, despite the appearing of P.intermedia in CF6 zone for the first time, but their development morphotype is appearing in CF5 zone (Li and Keller, 1998a) although the first appearing of P. intermedia in Jorband section is in the zone of CF10.this zone has 6m thickness. 3. Racemiguembelina fructicosa partial range zone li al 1998ª The Racemiguembelina fructicosa or CF4 Zone is defined by the FAs of R. friicticosa at the base and P. hariaensis at the top. The boundary of this zone is not abviously clear. This zone is equal with CF4 zone of Li and Keller (Li and Keller, 1998a) and li coworkers (Li et al, 1999) and has 7 m thickness and has an equal age with the beginning of upper maastrictian.

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Salinity appointing Appointing the salinity was done by echinocorys genus in this section. Echinocorys have a shell between medium and large, and a test with a high slope and a smooth basically surface, and have an angled ambitus with short and clear pins, in order to protect the adaptical surface. Also they have spoon pins which are connected to front mount surface with some lumpus, and they have to move and push the echinocorys forwarded (Clarkson 2006). They have an ambulacra which are not petaloids and are in large size and were seen a lot in upper maastrichtian sediments of late cretaceous in north of Alborz (Balmaki, 2007). The echinoids not only live in less salinity areas but also like in high salinity places. The affection of salinity changes is reveal in any of their surface. The salinity changes would affection abundance, death, population dispersion, moves, some change in nourish and metabolism behaviors, fastness of growth and reproduction (Wisshak and Neumann, 2006). The echinoids are a perfect group that used as a tool to interpretation the paleoenvironment. Some of echinoids do not have an obvious organism to regulate the osmotic pressure most of the spices have lived their habitat because of salinity changes and migrated to other places or die because of these changes. Echinocoryses are one of these groups. The salinity changes percent has indicated between -20 till -30 , it means that the maximum of salinity changes in echinocorys environment is 10 (Ellington , 1982) at all the echinocoryses abide the salinity 34 degree. The aminoacides number would increase in echinoids cell‘s in environmental situation changes that this behavior happens in echinocorys because of increasing the salinity of environment (Stephen & Virkar 1966). The main role of enzymes cells is to accelebrate the regulating reactions in amino acids. But in the situation which the environment salinity is increasing, they have a vice versa effect on enzymes, and would forbid the enzymes to work appropriately inside the cells (Ellington, 1982). In order to do the process of study in area, the salinity changes in the end of maastrichtian s presented as a chart with due attention to the counting and assessment of echinocorys in 3 layers, that the most number of this genus were there. In the beginning of section there is a less percent of this genus (30 percent). In the middle of section it is abundant s 80 percent and it will diminish again in the bottom and gets to 55 percent (Fig2). The ion body surface balance of echinocorys would be done during 12 till 24 hours because of salinity changes. The fluid of cell would increase the density amount of amino acids and K+ but it would decrease the concentration amount of Cl_ and Na+ increase it can effects on decreasing the echinocorys (Diehi, 1983). The regulation of osmotic pressure inside the echinocorys body possibly arises from the salinity amount changing and ion changing amount, of around environment that this can effects on test potential and can be a reason to activate that enzymes and shape changing of structure and surface. The amount of K+ is appointed about 11.5 and 13.4 in terms of litter (Beth & Berger, 1931). In this section the changes of echinocorys test is obviously clear.

Conclusion In end of maastrichtian in Jorband section, three zones of Contustruncana contusa, Planoglobulina brazoensis, Racemiguembelina fructicosa, were indicated based on the

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 planktonic foraminifera. The salinity changes were also determined in three layers in this section based on Echinocorys genus, the consequence is drawn as a diagram which in middle of the section, the salinity rate is fewer than the beginning and bottom of the section.

Refrence Abramovich, S., and Keller, G., (2002). High stress late Maastrichtian paleoenvironment: inference from planktonic foraminifera in Tunisia; Palaeogeography, Palaeoclimatology, Palaeoecology 178: 145-164. Adatte, T., Keller, G., and Stinnesbeck, W., (2002). Late Cretaceous to early Paleocene climate and sea-level fluctuations: the Tunisian record; Palaeogeography, Palaeoclimatology, Palaeoecology 178: 165-196. Balmaki, b, 2007, a symbiotic relationship of echinocorys faunas from the northern alborz mountains, 51st palaeontological association annual meeting , December 16-19, Uppsala, Sweden. Bethe A and Berger E. (1931) variationen im mineralbestand verschiedener blutaten. pflugers arch, ges. physiol. 227, 571-584. Caron, M., 1985- Cretaceous planktic foraminifera. In Bolli, H. M., Saunders, J. B., and Perch- Nielsen, K. (Eds.), Plankton Stratigraphy: Cambridge (Cambridge Univ. Press), 17–86. Diehl W. J. (1983) Pattern and mechanisms of isosmitic intracellular regulation in Luidia clathrata (say) (Echinodermata: asteroidean) exposed to hypo- and hyperosmotic stress. PH.D. Dissertation. University of south Florida, Tampa. Ellington W.R.(1982) intermediary metabolism. In echinoderm nutrition (edited by Jangoux M. and Lawrence J. M.), pp. 395-415. a.a. balkema, Rotterdam. Li, L. and Keller, G. (1998a). Maastrichtian climate, productivity and faunal turnovers in planktic foraminifera in South Atlantic DSDP Sites 525 and 21. Marine Micropaleontology 33, 55-86. Li, L. and Keller, G. (1998b). Maastrichtian diversification of planktic foraminifera at El Kef and Elles, Tunisia. Eclogae Geologicae Helvetiae 91, 75-102. Li, L., Keller, G. and Stinnesbeck, W. (1999). The Late Campanian and Maastrichtian in northwestern Tunisia: Paleoenvironmental inferences from lithology, macrofauna and benthic foraminifera. Cretaceous Research 20, 231-252. Nederbragt, A.J.,1991- Late Cretaceous biostratigraphy and development of Heterohelicidae planktic foraminifera. Micropaleontology, 37:329–372. Robaszynski, F., Caron, M., Gonzales Donoso, J.M., and Wonders, A.A.H., (1984). Atlas of Late Cretaceous Globotruncanids; Revue de Micropaléontologie 26, 145-305. Stephens G.C. and Virkar R.A. (1966) uptake of organic material by aquatic invertebrates. IV. The influence of salinity on the uptake of amino acids by the brittle star, Ophiactis arenosa. Boil. Bull. 131, 172-185. Wisshak, m. and Neumann, C. 2006. A symbiotic association of a boring polychaete and echinoid from the late cretaceous of Germany. Acta palaeontologica polonica 51(3): 589- 597.

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Fig 1.Location map of the studied area in the Iran.

Fig 2. Biostratigraphy and salinity change by planktonic foraminifera and Echinocorys

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Plate 1. A: SEM planktonic foraminifera. Scale bar = 100 μm and Echinocorys . Scale bar = 5cm 1. Racemiguembelina fructicosa (Smith & Pessagno) 2.Planoglobulina brazoensis (Martin) 3. Contusotruncanacontusa (Cushman) 4. Echinocorys sp.

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Listvenites as targets for Au-Hg mineralization in Central Iran ophiolites

Fatemeh Mohammadi* ,Moosa Noghreian** ,Mohammad Ali Mackizadeh** ,Babak Vahabimogha

*Islamic Azad university of khorasgan,Esfahan,Iran.

**Department of geology university of esfahan , Iran. E mail address:www. [email protected] Abstract Central Iran ophiolites are widespread in two main Belt ;Dehshir-Naien& Anarak –Jandaq. Serpentinites which are the main parts of these ophiolites,have undergone hydrothermal alteration in parts,so listvenites (or quartz-carbonate rocks) are occured. Listvenite occurence is due from interaction of CO2 bearing fluids on serpentinites.Listvenites are characterized by following mineral assemblage: Quartz,magnesite,dolomite,relicts of serpentine ,Cr-spinel,iron oxides the main texture of primary serpentinites always preserved as gohst texture.In the advanced process of hydrothermal alteration these rocks transformed to more silicified rocks called birbirites.There are some mineralized listvenites in Anarak ,Naien & Dehshir.Geochemical analysis have shown anomalies for Hg(up to 49ppm),Sb & As.SEM studiesdetermined visible gold in association with Iron oxides & Hg –minerals too, so in central Iran ophiolitescould account for a new target for Gold prospecting & exploration.

Keywords: Listvenite;Ophiolites;Serpentinites;Gold;Central Iran; Carbonate; Hydrothermal alteration.

Introduction The studied area is located in central Iran geological unit.(fig.1) Naien Ophiolite terrain exposed as a narrow band trending N- S in North of Naien town(fig.2). The ophiolite exposed beside or along major Naien- Baft in Iran. Tertiary sedimentary rocks & magmatic rocks (Eocene-Oligocen) are outcropped extensively in east & west of this opiolitic band respectively. Naien ophiolite is emplaced during upper cretaceous to paleocen, regarding to age of other rock unites in vicinity of ophiolite. The main constituents of ophiolite are harzburgite, serpentinite, Pyroxemite, gabbro diorite, plagiogranite , massive & pillobasalts, also lehrzolite , dunite & wherlite are less abundant in the field .

Hydrothermal alterations Hydrothermal alteration are widespread within serpentinites of Nain ophiolite, The most outstanding of those including: Carbonatization & Rodingitizaion. Carbonatization is take place along main faulting & fracturing within serpentinites with other ophiolite unites(fig.3,4,5). Roadingitizaion occurred only in gabbro dykes or boudines in serpentinizesd harzburgites. It is obvious that Co2 rich fluids are resulted in listventies or Quartz- Carbonate rocks. In field outcrops listvenites are present sas out standing peaks or small trends in serpentinites. Their color varies from pale-brown to brown which in some cases, they may be mistaken by

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 pelagic limestones from ophiolite mélange. Silicified patches or parts in listvenites are also outstanding & occurred in dark gary to very dark brown. With high relief in listvenite host rock. Iron oxides coloring, probably due to oxidation or decomposition of pyrite often accompanying the listvenite outcrops specially silicified parts. Sometimes there is aboundant veins of quartz- chalcedony & dolomite in listvenites. In petrographic studies the following critical assemblages are distinguished(fig.6,7): quartz+ Mg-Fe carbonates (Mangnesite , dolomite) Cr- Spinel ± Serpentines ± opaque minerals ± chlorite. Relics of Cr- spinel or chromite & Serpentine shows that the ultramafic nature of primary rock. In some cases ghost texture of host serpentinite (mesh texture) are well preserved in listvenite but the granoblastic texture is common silicified parts are characrerized by very fine grained texture of quartz likely as cherts or jasperoids. Ore petrography revealed the exsistence of chromite , pyrite, hematite & goetite disseminations.

Hg- Au Mineralization SEM studies also showed that the sulphide mineralization is only restrict to silicified Zones. Pyrite is mainly occurs as disseminations and less seen massive. There is also some oxidized pyrite which well preserved the primary cubic form (pseoudomorph) Hg- Mineralization (fig.8,9) is associated with pyrites & oxidized pyrite (pseoudomorph) & also massive products of pyrite oxidation (Hematite & goetite). Hg ore minerals are found as anhedral shope, tiny dropes of Hg & Pore space filling. Gold mineralization also is found as micron sized particles along fractures in silicified groundmass.(fig.10,11)

Fig.1-Geological divisions of Iran and position of Nain ophiolite.

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Fig.2-Geological map of North of Nain and position of listvenitized zones.

Fig.3-Field outcrope of listvenite the silicified parts are most outstanding

Fig.4-Tectonic contact of serpentinite ,whith listvenite.(transition zone).

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Fig.5-Veinlets of quartz ,chalcedony and dolomite.

Fig.6-Association of dolomite and finely crystallized quartz ,late quartz veinlets are common in listvenites .XPL×100.

Fig.7-Late oxidized margine of Fe dolomite which is characterized by brown staining in margines of dolomites.XPL×100.

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Fig.8-Hg mineralization in groundmass of silicified.

Fig.9-SEM analysis of Hg-compound.

Fig.10-Micron size of gold grain which is emplaced in a Fracturing

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Fig.11-SEM analysis of gold grain.

Refrences 1-Noghreian,M.Mackizadeh,M.A.&Sharafat,S,1997,Petrography and geochemistry of listvenites in central Iran ophiolites:research project,Isfahan University,66pp.unpublished. 2-Aybal,D,1990,Gold-bearing listvenites in the Arac Masif,Kastamonu,Turkey,Terra Nova,V.2.P43- 51. 3-Davoudzadeh,M.,1972,Geology and petrography of the north of Nain,central:Iran Report no,14. 4-Henderson,F.B.,1969,Hydrothermal alteration and ore deposition in serpentinite type mercury deposits:Economic Geology,vol.64,pp.489-499. 5-Levinson,A.A.,1980,Introduction to exploration geochemistry:924p.Elsevier Publication. 6-Verdehburgh,L.M.,1982,Tertiary gold bearing mercury deposits of the coast range of California geology.P.23-27.

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Formation of Magnesian Iron Skarn at Bashkand, SW of Soltanieh, NW Iran

Somayeh Shahbazi *,Majid Ghaderi, Nematollah Rashidnejad-Omran

Department of Geology, TarbiatModares University, Tehran, Iran * E-mail address: [email protected] Abstract Bashkand iron deposit is located 16 km southwest of Soltanieh, in northwestern part of Central Iran structural zone. Rock units in the area include alternations of phyllite, slightly recrystallized dolostone and meta-tuff of Kahar Formation as well as subvolcanic bodies of granite composition and dolerite- diabase dykes intruding Kahar Formation. Mineralization in the deposit has the same trend as contact of the intrusive body. Ore textures are vein-veinlet, diffusion, replacement, banded, dendritic, residual and massive. The main ores at Bashkand are magnetite, hematite (specularite), pyrite and chalcopyrite. Secondary minerals include goethite, limonite, lepidocrocite and malachite. Gangue minerals are quartz,calcite, garnet, pyroxene, amphibole, epidote, serpentinized forsterite, talc, chlorite, tourmaline, actinolite and tremolite. Epidotization, actinolitization, sericitization, serpentinization, carbonatization and silicification are the most important alteration types in the area. Based on congruency of mineralization with the contact of granitic intrusions and carbonate-dendritic rocks, textures such as banded, dendritic, residual and massive, occurrence of magnetite simultaneous with garnet formation, replacement of epidotic and actinolitic pyroxene for dolomite, occurrence of forsterite casts filled with antiguritic serpentine, presence of alterations such as actinolitization, epidotization, carbonatization, serpentinization and silicification, it is likely that the Bashkand iron mineralization formed as a result of intrusion of a subvolcanic granite into the Kahar Formation. Main oxides distribution patterns in igneous rocks in the surroundings of the deposit suggest that they were formed in an oceanic island environment.

Keywords: Iron mineralization, alteration, textures, oceanic island, Bashkand, Soltanieh

Introduction Bashkand iron deposit is located 16 km southwest of Soltanieh, 54 km southeast of the city of Zanjan in northwest Iran between 48˚40´00˝ - 48˚41´00˝ longitude and 36˚24´19˝ - 36˚26´00˝ latitude. Nabavi (1976) suggested that the region is situated in Western Alborz – Azarbaijan zone. However, recently, Sheikholeslami et al. (in press) proposed that the region is in the edge of northwest Central Iran structural zone. Other iron deposits in the region include Arjin (Andarz, 2006), Shahbolaghi (Esmaili, 2006), Gouzal-darreh and Kardaragh (Ghorbani, 2002). Discussion Geology Based on field and microscopic studies, rock units in the area can be divided into four groups that according to age include (Fig. 1): 1) Alternation of recrystallized dolomite and phyllite with intercalations of meta-siltstone, and meta-tuff belonging to upper parts of Kahar Formation. 2) Recrystallized limestone layers of Bayandor Formation which rest over the Kahar Formation through a normal fault.

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3) Subvolcanic granitic body that cuts Kahar layers, so that phyllite xenoliths can be noticed within the body (Fig. 2). 4) Doleritic-diabasic dykes with unclear source and age which cut Kahar and Bayandor formations. Kahar and Bayandor layers have N35-50W trend and S30-50E dip. The majority of faults and fractures in the area which triggered the movement of the host rocks have N35-50W trend. Most of the ore zone trends conform to this trend. There are also some faults and fractures with NE-SW trend which mainlymake the boundaries between the layers.

Ore mineralization Ore mineralization in the Bashkand area occurred between debris and carbonate units particularly wherever the intrusion body is outcropped (Fig. 2). In this area, ore formation has occurred wherever subvolcanic tectonized microgranular porphyritic body intruded recrystallized dolomite, meta-siltstone and phyllite units. Ore zones have a range of thickness from millimeters in the banded parts to 7-8 meters in the massive parts. Joints and fractures cutting foliation of the host rocks are suitable places for ore mineralization; however, those are less important as compared with the boundaries between recrystallized dolomite, metasiltstone and phyllite. Meinert et al. (2005) believed that in skarns related to intrusion body, exist bearing there is a relationship between replacing, crystallization and cooling events of intrusion body with metamorphism, metasomatism and retrograde alteration in surrounding rocks. In other words, during intrusion of the body, surrounding rocks undergo metamorphism. Recrystallization arising from metamorphism and phase change shows the protolith components. Local bimetasomatism and circulating fluids form various calc-silicate minerals (reaction of skarn and skarnoid). Crystallization and releasing of liquid phase form metasomatism skarn. Cooling of intrusion, separating of volatile phase and circulating of cooler meteoric waters, cause retrograde alteration of calc-silicate minerals that had formed during metamorphism and metasomatism stages. It is noted that in deeper parts, metamorphism is more extensive and the temperatures are higher; while in shallow parts, retrograde alteration has more extent (Meinert et al., 1992). In conformity with the above-mentioned sequence, it must be said that metamorphic halos in the Bashkand area were not found. This could be due to the following reasons: 1) The intrusive body in the Bashkand area was quite fractionated, acidic and therefore had experienced a very low temperature 2) The magma intruded the shallow parts of the crust, forming a subvolcanic body. 3) The surrounding rocks, before intrusion of the body, during an older phase (probably Katangai), metamorphosed in greenschist facies, therefore, the intrusive could not increase the metamorphic grade and could not create a metamorphic halo. However, during crystallization of the intrusive, bands of garnet and pyroxene with some magnetite formed within the recrystallized dolomite, phyllite, meta-siltstone and meta-tuff units (Fig. 3). In the next step, simultaneous with cooling of the intrusive and separation of vapor phase and circulation of cooler meteoric water, retrograde alteration caused garnet turn into epidote, olivine into serpentine (antigorite) and pyroxene into amphibole, serpentine and

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 epidote. Most part of ore mineralization occurred in this step. Finally, siliceous and carbonaceous vein-veinlet cut all of the assemblage.

Ore structure and texture Ore textures in the area include banded, diffusion, replacement, massive and dendritic. Banded texture is mostly seen in parts where host rock include intercalation of recrystallized dolomite, meta-siltstone and meta-tuff (Fig 3). Ciobanu and Cook (2004) reported similar texture from Ocna de Fier - Dognecea ore field (a Pb-Zn deposit). Replacement is seen in recrystallized carbonate parts (Fig. 4). Dendritic texture is observed in both recrystallized carbonate and phyllite (Fig. 5). Within the rims of the veins, sulfide minerals such as pyrite and chalcopyrite can be seen. Meta-tuffic and meta-siltstone parts have scatter magnetite crystals which cut the rockforming minerals. In some instances, magnetite crystals together with potassic alteration that has originated from the intrusion body, intrude these parts (Fig. 6). Since the recrystallized dolomite, meta-tuff, meta-siltstone and phyllite have each a thickness of less than 10 cm, usual regional zoning of skarn deposits is seen in the Bashkand area in millimeter to centimeter scale and has alternately been repeated.

Mineralogy The main minerals at the Bashkand deposit are magnetite, hematite (specularite), pyrite and chalcopyrite. Secondary minerals include goethite, limonite, lepidocrocite, chalcocite and covellite. Gangue minerals are quartz, calcite, pyroxene, garnet (spesartin), amphibole, epidote, chlorite, alumino-silicate, tourmaline, serpentine, clay minerals (according to XRD analysis illite and kaolinite), actinolite and tremolite. According to field and microscopic studies, ore paragenesis includes magnetite, hematite, pyrite and chalcopyrite, chalcocite, covellite, goethite, malachite, azurite and limonite.

Alteration Alteration in igneous rocks include epidotization, sericitization, carbonatization and chloritization (sosoritic alteration) (Fig. 7). In phyllite include sericitization and in recrystallized dolomite include epidotization, carbonatization, actinolitization (Fig. 8) and serpentinization. During alteration of olivine and pyroxene serpentine, iron is released (Fig.9).

Tectonic environment Four samples were chosen for ICP analysis and drew tectonic environment diagram. According to TiO2, MnO*10, P2O5*10 diagram, Bashkand iron deposit formed in an island arc environment (Fig. 10).

Conclusion Considering the mineralization being parallel to the contact of metamorphosed carbonate and detrital rocks adjacent to the intrusion, showing textures such as banded, dendritic, residual and massive, replacement of epidotic and actinolitic pyroxene for dolomite, presence of alterations such as actinolitization, epidotization, sericitization, carbonatization and silicification, it is likely that the Bashkabd iron mineralization formed due to intrusion of

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References 1) Andarz, F. (2006). Mineralogical study and ore-controlling parameters of magnesian iron skarn mineralization at Arjin mineralized area located east of Zanjan (Zanjan province), MSc thesis, Islamic Azad University (Science and Research Branch), Tehran, Iran. 2) Ciobanu, C.L., Cook, N.J. (2004). Skarn textures and a case study: the Ocna de Fier - Dognecea ore field, Banat, Romania, Ore Geology Reviews, v. 24. 3) Einaudi, M.T., Meinert, L.D., Newberry, R.J. (1981). Skarn deposits, Economic Geology, 75th Anniversary Volume, p. 317-391 4) Esmaili, M. (2006). Mineralogy, geochemistry and genesis of Shahbolaghi iron deposit (west of Zanjan), MSc thesis, Shahid Beheshti University, Tehran, Iran. 5) Ghorbani, M. (2002). A preface to economic geology of Iran, National Geoscience Database of Iran. 6) Lentz, D.R., Walker, J.A., Stirling, J.A.R. (1995). Millstream Cu-Fe skarn deposit: an example of a Cu-bearing magnetite-rich skarn system in northern New Brunswick. Exploration and Mining Geology, v. 4, p. 15-31. 7) Meinert, L.D. (1992). Skarn and skarn deposits, Geoscience Canada, v. 19, n. 4. 8) Meinert, L.D., Dipple, G.M., Nicolescu, S. (2005). World skarn deposits. Economic Geology 100th Anniversary volume, p. 299-336. 9) Mullen, E.D. (1983). MnO/TiO2/P2O5: a minor element discriminant for basaltic rocks of oceanic environments and its implications for petrogenesis, Earth and Planetary Science Letters, v. 62, p. 53-62. 10) Sheikholeslami, M., Aghanabati, A., Vahdati, F., Sahandi, M., Amini, B., Jafarian, M. (in press). Iran structural zones, Geological Survey of Iran.

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Fig1: Geological map of Bashkand area1:5000.

Fig. 2: Granitic subvolcanic, phyllite, recrystallized dolomite and banded skarn at Bashkand.

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Fig. 3: Bands of ore, skarn minerals and metamorphic host rocks.

Fig. 4: Replacement of mineral host rock by magnetite.

Fig. 5: Dendritic texture of ore in the recrystallized dolomite.

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Fig. 6: Assistance of magnetite with potassic alteration (brown bands in the picture) in phyllite.XPL light, 10 x.

Fig. 7: Sosoritization in the granite subvolcanic.

Fig. 8: Actinolitization and epidotization in impure and tuffic recrystallized dolomite.

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Fig. 9: Changing pyroxene and olivine to serpentine and to be released of Iron.

Fig. 10: Diagram showing tectonic environment. CAB: Calcalkaline basalts of island arc. IAT: Tholeiites of island arc. MORB: Mid Ocean Ridge Basalts. OIA: alkali basalts of Island arc. OIT: Tholeiites of island arc. Bon: Boninites (Mullen,

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Investigation and nomination of Gheysar blind fault focal mechanism by aftershocks' distribution and aeromagnetic data in Aryan-Shahr area, N- Birjand

H. Yazdanpanah1*, M.M. Khatib2, S.S. Ahmadizadeh3

1* Department of Geology, University of Birjand, Birjand, Iran, [email protected]

2 Department of Geology, University of Birjand, Birjand, Iran, [email protected]

3 Department of Environment Science, University of Birjand, Birjand, Iran, [email protected]

Abstract th In March 9 , 2008 an earthquake with ML=5.1 occurred in Aryan-Shahr area, 55 km north of Birjand, East of Iran. More than 100 aftershocks were recorded within 8 days after the main shock. At first, the fault with N76 trend was informed as source of this earthquake. But the distribution of aftershocks has been occurred in an ellipsoid district, that the long axe of this ellipsoid is not parallel with Sedeh Fault. The long axis of distribution ellipsoid of aftershocks (N120) is nearly perpendicular to the Sedeh fault trend. Investigation of aftershock epicenter dispersal and the interpretation of aeromagnetic data make known the existence a blind fault parallel to long axis of distribution ellipsoid of aftershocks, which has been named Gheysar blind fault. The Gheysar blind fault with ~39 km length and trends of N126, appears to has a thrust component, and gently dipping (~20°SW).

Key words: Aryan-Shahr, Aeromagnetic data, Gheysar blind fault, Sedeh Fault

1. Introduction The initial stages of fault development have been recognized in laboratory experiments, but not at seismogenic depths. To fully understand how faults initially develop and begin to evolve, one needs to first recognize and then observe the emerging structure. Recognizing the birth of a fault requires a priori knowledge of the regional tectonics, geologic structure, and seismic history. This information is needed to assess the likelihood that earthquake hypocenters that occur far from known faults represent new fault formation rather than slip at depth on existing structures. Furthermore, young faults may begin as blind structures, which make them difficult to recognize. The 1994 Sefidabeh earthquake (berberian et al. 2000), 2003 Bam earthquake (Bihong and Xinglin 2007) revealed the significance of blind thrust faults in East IRAN. Dissimilar the expose active fault, blind faults are difficult to recognize because they aren't visible and haven't surface ruptures. Even after a blind fault is identified, it is difficult to determine whether the fault is active (Lettis et al., 1997). We present evidence for an incipient, blind, thrust fault in southwestern Aryan-Shahr town that is associated with the March 9th, 2008 Aryan-Shahr earthquake. As in Aryan-Shahr area, these active thrusts occur adjacent to active strike-slip faults, thus raising the question of how these fault types interact and contribute the regional deformation.

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We use the techniques of Satellite Images process and Shuttle Radar Thematic Maps (SRTM) to examine small-scale features in the deformation field associated with the Aryan-Shahr earthquake. The study area is located in north part of Sistan suture zone and partial North Lut (Fig. 1a, b). The fundamental premise of earthquake-hazard reduction in the U.S. is that most earthquakes take place along active faults that suddenly fail and slip. Large earthquakes take place along large faults, and large faults, it is widely held, cut the earth's surface. Geologists recognize faults that have displaced young surface deposits as having recently been active and deem them the most likely to rupture again. This reasoning has yielded profound insights into earthquake behavior, making it possible to situate critical facilities-such as power plants and dams-away from active fault sites, to identify sites with high seismic potential and to make probabilistic forecasts of earthquake size and frequency. Yet in March 9th, 2008 Aryan-Shahr most small earthquakes do not occur along faults that cut the earth's surface. Previous seismicity studies (Berberian et al., 1999, Walker and Khatib, 2006, Walker et al., 2003, 2004) and geologic maps (Berthiaux, 1989, Eftekharnezhad and Vahdati, 1992, Eftekharnezhad and Valeh, 1997) of the area do not show a surface expression of a fault, geologic structure, or tectonic landform corresponding to the March 9th, 2008 Aryan-Shahr earthquake and aftershocks. In this paper, Investigation of blind active fault by assimilates aftershock epicenter dispersal and the interpretation of aeromagnetic data. We investigate the distribution of aftershock zones for large earthquakes scalar seismic moment magnitude main shocks and aftershocks are selected from the IRSC website (http://www.irsc.ut.ac.ir). One of preferences of remote sensing in geology is wide cover of study area that gives useful information of structural pattern. Faults and fractures are structures that were recognized by satellite images. For recognizing the liner structures and analyzing structure of Aryan Shah Region in the north west of Birjand use the digital data of TM sensor. By using Optimum Index Factor the most suitable false color combination was obtained. After that the spatial high pass filters and the effect of sun radiation angle and transportation in the data histogram were used. In the next stage the study area faults, mechanism and relation of them were recognized (Fig. 1b)

2. Geological and Geomorphologic overview The Aryan-Shahr area is located in north of sistan suture zone in E-Iran (Fig. 1). This zone is separated from Afghan block, Lut block and Makran zone by these boundaries. N-S spreading of this zone is ~800 km and its width is 200 km. In fact, this zone has been formed from sediment of accretionary prisms between Lut and Afghan block by convergence phases at Senomanian-Oligomiocen time. Nevertheless abundance of calcalkalin volcanic rocks in northern part of the Lut block (Tirrul et al., 1983) considered the sense of subduction toward to north and east, below the Lut block. Separation between Lut and Afghan block has created oceanic crust in Middle Cretaceous and flysch depositions formed simultaneously. Gradual convergence of Lut and Afghan at Middle-Late Oligocene time caused folding, fracturing and

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 uplifting in this area. Finally intense magmatic activation have appeared at Neogen time and concentrated in main fault margin. Several present-day tectonic land forms have been used to indicate the activeness of crustal structures (Keller & and Pinter, 1996). These landforms of both primary and secondary features can be clearly seen by the uses of remote-sensing information. There are several tectonic landforms, such as offset streams, shutter ridges, and vine glass valleys, which are important for investigations of tectonic geomorphology. Recently with the application of ArcGIS and the DEM, several morphotectonic investigations can be easily evaluated with a very low cost and high quality results. Most of Aryan-Shahr area is flat, one-third is covered by hills between 200 and 400m height from the plain and only a very small part of the points are rise above 400m. Neotectonic evidences are shown that the study area is active. Even though the tectonic movements are very young, and the uplift rate is considerable. The observation data's shows the study areas have high potentials of tectonical activity. Field photographs of neotectonic evidence in Aryan-Shahr area shows in Fig. 2.

3. Aryan-Shahr earthquake Tectonic deformation refers to regional deformation that may or may not be associated with moderate or large earthquakes. There are earthquake epicenters concentrated in the border active faults (Quaternary faulting), and all similar trending active fault with distributions of epicenter locations. Even though there are no mapped faults which these earthquakes easily can be tied to, there is morphological lineation in that direction.

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a b

Figure 1. Geological location of Aryan- Shahr area. (a) Yellow circles are earthquakes in the period 1964–2002 from the catalogue of Engdahl et al., 1998 and subsequent updates. Red arrows are velocities (in mm/yr) of points in Iran relative to stable Eurasia, measured by GPS from Vernant et al. 2004). The green circle is the epicenter of the March 9th, 2008 Aryan-Shahr earthquake. Box shows the location of fig. 1b. (Jackson et al., 2006) (b) Shaded topographic image, from SRTM data, of the east Iran. Note the major faulting in eastern Iran. Box shows the location of fig. 3, 4.

a b

~

1 1

~ m

6 c m d

~

4 T 8 T e

m e r r r r a a c c e e

Figure 2. Field photographs of neotectonic evidence in Aryan-Shahr area. (a) A typical gully incised through the uplifted ridge, at 33° 17N 59° 08E, looking northeast. (b) View NW of the ~17 m high scarp (32° 25N 59°E). (c) View E of a right-lateral offset of the river in Chahak fault trend (32° 20N 58° 49E). (d) View upstream (NE) at the village of Mahmoee (33° 19N 59° 21E), showing a river incised through the uplifted hanging wall, leaving behind abandoned fan surfaces as terraces.

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th In March 9 , 2008 partly violent earthquake of ML=5.1 shook west of Aryan-Shahr city in the North of Birjand, East Iran. This earthquake not killed persons but destroyed somedeal neighbor villages. Shortly after earthquake Tehran university institute of geophysics network installed in area recorded more than 100 aftershocks for three mounts. All data of 3 stations were processed, common aftershocks were separate, their parameters were determine and were drawn on fault map. Therefore distribution of aftershocks location and main shock geometry of causing fault is known. Results show that causing fault has 39 Km length, and average 6 Km depth. These results not confirm by geology data and Field investigation. Most major faults in Aryan-Shahr area reach, and thus intersect with, the surface of the earth. This intersection of the fault plane with the surface produces a linear feature called a fault trace. The active crustal faults include the Sedeh, Shah-Abad, Chahak, Dasht-e-Bayaz and Afriz faults, the not source of the damaging Aryan-Shahr earthquake (Fig. 1b, 3). Too some faults, do not reach the surface. Aftershock pattern by the Gaussian distribution cannot be exact; some aftershocks occur at large distances from the main shock where not her traces of earthquake rupture can be found as the aftershock sequence. Also distribution of aftershocks location and main shock geometry of causing fault is known. For the 8 days after the earthquake 9th, March 2008 in Aryan-Shahr a dense seismic network of 3 stations was operated in the epicenter region to record aftershocks. The majority aftershock distribution delineates has been occurred in an ellipsoid district, that long axis of distribution ellipsoid of aftershocks an intense NW-SE zone of activity (Fig. 3).

Figure 3. Aftershock locations for the March 9th, 2008 Aryan- Shahr earthquake. Locations of the best-located 106 aftershocks from March 9th, to March 17th, 2008. Note the distribution ellipsoid of aftershocks in Aryan-Shahr region.

4. Aeromagnetic evidence This magnetic data on this paper were compiled from information recorded along the flight lines, which were flown at 7.5 km. spacing in a direction perpendicular to the primary geologic trend within each block. Tie lines were flown with a 40 km spacing perpendicular to the traverse lines. The regional gradient of the earth's field has been removed. Magnetic counters show total intensity field in gamma. Regional gradient has been removed as

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 explained elsewhere. If the fault plane terminates before it reaches the earth's surface, it is referred to as a blind thrust fault. Because of the lack of surface evidence, blind thrust faults are difficult to detect until they rupture. The March 9th, 2008 earthquake in Aryan-Shahr was caused by a previously-undiscovered blind thrust fault. In this study, Use of Aeromagnetic Data one technique is for recognition Blind fault.

Figure 4. Applied filter by Geosoft software for aeromagnetic data processing in Aryan-Shahr area. (a) Reduction to the pole filtering. (b) Upward continuation filtering. (c) Downward continuation filtering.(d) Horizontal derivative filtering. (e) First derivative filtering. (f) Second vertical derivative filtering.

By Reduction to the pole, Upward and Downward continuation, Horizontal, First and Second vertical derivative filtering in Geosoft software recognize blind fault in Aryan-Shahr area (Fig. 4). So, we identify four blind faults in study area, and named Gheysar, Room-Chelunak, Shushood and Gazar blind faults (Fig. 5).

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Figure 5. Blind fault identified by aeromagnetic data process.

5. Aftershock locations and Gheysar blind fault mechanism Focal mechanism solutions of the area‘s earthquakes have been displayed to reveal mechanisms of seismicaly active fault zones. These solutions indicate dominance of thrust faults in a compressive regime fore vast majority of earthquake of Aryan-Shahr. Active fault in Aryan-Shahr area are blind and the focal mechanism solution of the earthquakes of the region points to the presence of thrust faulting in its basement. The aftershock zone is sub vertical beneath the Gheysar blind fault trace, broadening with depth (Fig. 6a, b, c). In this study, we suggest that the aftershock zone has a steep (~20°) Southwestward dip. Nearly all the best-determined locations lie in the range 1–9 km, and thus almost entirely below the 2–8 km depth range in which most of the slip occurred in the main shock, and which produced the subsurface deformation revealed in the Gheysar blind fault (Fig. 6d). The depth range of maximum slip in the main shock is nearly completely free of aftershocks in the Fig. 6d. This is a very significant observation as it suggests that the thickness of the seismogenic zone in the region is about 30 km, and that not ruptured in the Aryan-Shahr main shock. An important question is whether the unruptured may still fail seismically in a future event. Their results were much the same, demonstrating a thickness to the seismogenic layer of ~ 30 km, and a relative lack of surface rupture above the Gheysar blind fault.

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a b H

M

Gheysar blind fault trend c

d

Figure 6. (a) 3D perspective image of the Aryan-Shahr area. Open box A-B up to L-I is location of cross section in fig. 6b. (b) Cross section along axis of distribution ellipsoid of aftershocks. Black points are main shock, and red points are aftershocks. Red arrows are projection Gheysar blind fault in surface. (c) In total cross-section fig. 6b, Gheysar blind fault trace is well-defined steeply dipping fault. Since cross section is perpendicular to Gheysar blind fault, not to fault splay, distribution about fault splay is artificially widened. (d) A northwest-southeast section along the line of the gheysar blind fault, showing the 106 high-quality aftershock locations of author. The depth range of maximum slip in the main shock is nearly completely free of aftershocks.

On the basis of the seismicity pattern and focal mechanisms, we infer that the Gheysar blind fault is likely a small displacement strike-slip fault zones. This could be consistent with an incipient fault, and the clear activity at both ends should evolve, with time, toward a connected through going fault. The lack of a surface expression associated with the seismic lineament may be because it is a young fault that has had little throw. In numerous examples around the world, active strike-slip faults appear to end in dip-slip faults, with displacements that die away from the junction between the two [e.g., Bayasgalan et al., 1999; Berberian et al., 1999b, 2000; Meyer et al., 1998; Parsons et al., 2006]. The Nauzad thrust along the northern margin of Kuh-e Mo‘inabad is an example of this type of structure with the thrust linking at its eastern end to the Purang strike-slip fault [see Berberian et al., 2000, Figure 14].

6. Conclusion The close proximity and orientations of the Gheysar seismic lineament and the Shah-Abad fault suggest that these two structures are related. The seismic lineament may represent an extension or propagation of the Shah-Abad fault towards the northwest. In this study, by combining neotectonic evidence, aftershocks' distribution and aeromagnetic data, one can better quantify the seismic potential of regions where strain rates are high, and identify

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Gheysar blind fault mechanisms. Also, with the attention of the importance of basement faults without any surface fault in data base of earthquake source and the importance of basement depth & sediment coverage thickness research in the investigation of damage intensity in other regions. The Gheysar blind fault with ~39 km length with a near N126 trend which appears to has a thrust component, and gently dipping (~20°SW), perform important role in the seismicity analysis of Aryan-Shahr area. Our conclusion is that in regions where blind faults are present, the cumulative surface deformation from many repeated earthquakes will leave surface diagnostic of active faulting in the landscape, such as the diversion or abandonment of river channels, abrupt changes from river incision to deposition and abandoned terrace surfaces that can be identified in satellite imagery and the field.

References - Ambraseys, N.N., Melville, C.P., 1982: A history of Persian earthquakes. Cambridge University press, Cambridge, UK. - Bali, F., and Antes, A., 2003: Analytic signal interred from reduced to the pole data. Journal of the Balkan Geophys. Society, Vol. 6, No. 2. - Baraboo, V., and Needy, H., 1964, Numerical calculation of the formula of reduction to the magnetic pole. Geophys. 29. - Bayasgalan, A., J. Jackson, J.-F. Ritz, and S. Carretier (1999), Field examples of strike-slip fault terminations in Mongolia and their tectonic significance, Tectonics, 18, 394 – 411. - Berbarian, M., 1976: Contribution to the seismotectonics of Iran (Part II). Geological Survey of Iran, Rep. No. 39.

- Berberian, M., 1977: Macro seismic epicenter of Iranian Earthquake in: contribution to the seismotectonic of Iran. Geological Survey of Iran, Rep. No. 40. - Berberian, M., Jackson, J.A., Qorashi, M., Khatib, M.M., Priestley, K., Talebian, M., and Ghafuri-

Ashtiani, M., 1999a: The 1997 May 10 Zirkuh (Qaenat) earthquakes (Mw=7.2): faulting along the Sistan suture zone of eastern Iran, Geophys. - Berberian, M., and R. S. Yeats, 1999b: Patterns of historical earthquake rupture in the Iranian plateau, Bull. Seismol. Soc. Am., 89, 120 – 139. - Berberian, M., J. A. Jackson, M. Qorashi, M. Talebian, M. M. Khatib, and K. Priestley, 2000, The 1994 Sefidabeh earthquakes in eastern Iran: Blind thrusting and bedding-plane slip on a growing anticline, and active tectonics of the Sistan suture zone, Geophys. J. Int., 142, 283–299. - Berthiaux, A., et al., 1989: Geological map of Qayen. scale 1:250000, Geol. Surv. Of Iran. - Bihong F., and Xinglin L., 2007: A new fault rupture scenario for the 2003 Mw=6.6 Bam earthquake, SE Iran: Insights from the high-resolution Quick-Bird imagery and field observations. Journal of Geodynamics 44. - Eftekharnezhad, J., Vahdati, F., 1992: Geological nap of Iran, sheet Birjand, scale 1:250000, Geol. Surv. Of Iran, Tehran. - Eftekharnezhad, J., Valeh, F., 1997: Geological nap of Iran, sheet Ferdows, scale 1:250000, Geol. Surv. Of Iran, Tehran.

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- Jackson, j., et al., 2006: Seismotectonic, rupture process, and earthquake-hazard aspects of the 2003 December 26 Bam, Iran, earthquake. Geophys. J. Int., 3056. - Meyer, B., P. Tapponnier, L. Bourjot, F. Metivier, Y. Gaudemar, G. Peltzer, G. Shunmin, and C. Zhitai (1998), Crustal thickening in Gansu-Qinghai, lithospheric mantle subduction, and oblique, strike-slip controlled growth of the Tibet Plateau, Geophys. J. Int., 135, 1 – 47. - Neawsupart, K., Charusiri, P., and Meyers, J., 2005: New processing of airborne magnetic and electromagnetic data and interpretation for subsurface structures in the Loei area, Northeastern Thailand, Science Asia, Vol. 31. - Parsons, B., T. Wright, P. Rowe, J. Andrews, J. Jackson, R.Walker,M. Khatib, M. Talebian, E. Bergman, and E. R. Engdahl, 2006: The 1994 Sefidabeh (eastern Iran) earthquakes revisited: New evidence from satellite radar interferometry and carbonate dating about the growth of an active fold above a blind thrust fault, Geophys. J. Int., 164, 202–217. - Tirrul, R., Bell, I.R., Griffis, R.J., Camp, V.E., 1983: The sistan suture zone of eastern Iran. Geological Society of America Bulletin. - Vernant, Ph., Nilforoushan, F., Hatzfeld, D., Abbassi, M. R., Vigny, C., Masson, F., Nankali, H., Martinod, j., Ashtiani, A., Bayer, R. Tavakoli, F., Chery, J., 2004: present-day crustal deformation and plate kinematics in the Middle East constrained by GPS measurements in Iran and northern Oman. Geophys. J. Int. - Walker, R., Jackson, J, and Baker, C., 2003: Surface expression of thrust faulting in eastern Iran: souece parameters and surface deformation of the 1978 Tabas and 1968 Ferdows earthquake sequences. Geophys. J. Int. 152, p. 749-765. - Walker. R. T., Khatib, M. M., 2006: Active faulting in the Birjand region of eastern Iran. Tectonics, V. 25, TC4016 (1-17).

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Use of sawdust of Aspen tree for the removal of Chromium(VI) from aqueous solution

H.T. Hamed Mosavian 11, Khazaei2, M. Aliabadi 2

1- Ferdowsi University of Mashhad, Chemical Engineering Department,

2-Azad University, Birjand Branch,

Abstract Adsorption capacity of Cr(VI) onto sawdust of aspen tree and activated sawdust, was investigated in a batch system by considering the effects of various parameters like contact time, initial concentration, pH , temperature, agitation speed, absorbent dose and particle size. Cr(VI) removal is pH dependent and found to be maximum at pH 2.0. The amounts of Cr(VI) adsorbed increased with increase in dose of both adsorbents and their contact time. Experimental results show that the low cost biosorbent was effective for the removal of pollutants from aqueous solution. The Langmuir, Freundlich and Temkin isotherm were used to describe the adsorption equilibrium studies of agrowaste. Freundlich isotherm shows better fit than Langmuir and Temkin isotherm in the temperature range studied.

Keywords: Chromium, aqueous, lignocellulosic solid wastes, Adsorption, sawdust

1.Introduction Hexavalent chromium is present in the effluents produced during the electroplating, leather tanning, cement, mining, dyeing and fertilizer and photography industries and causes severe environmental and public health problems. Hexavalent chromium has been reported to be toxic to animals and humans and it is known to be carcinogenic [3]. The permissible limit for hexavalent chromium in industrial wastewaters is 0.1 mg/l and in potable water is 0.05 mg/l [5]. In order to reduce Cr(VI) in these effluents to the standard level, an efficient and low cost method needs to be developed. The various methods of removal of Cr(VI) from industrial wastewater include filtration, chemical precipitation, adsorption, electrodeposition and membrane systems or even ion exchange process. These techniques apart from being economically expensive have disadvantages like incomplete metal removal, high reagent and energy requirements, and generation of toxic sludge or other waste products that require disposal. Efficient and environment friendly methods are thus needed to be developed to reduce heavy metal content. In this context, considerable attention has been focused in recent years upon the field of sorption by lignocellulosic solid wastes such as straw, coconut husks, exhausted coffee [4], waste tea [9], seeds of Ocimum Basilicum , bark, walnut shell, straw and plant root [11], defatted rice bran, rice hulls, soybean hulls and cotton seed hulls [10, 14], wheat bran, pea pod, cotton and mustard seed cakes, [6], paddy straw [13], coir pith[7], sawdust and pine leaves [1].

1 . Corresponding author: [email protected] or [email protected]

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2. Materials 2.1. Adsorbents Sawdust of Aspen tree was prepared from agricultural solid wastes as adsorbents (major agricultural wastes of Birjand, Iran). Sawdust were soaked with 1 M HCL solutions for 30 min, rinsed several times with deionised water, oven dried at 1000C and used for activated sawdust. Samples were pulverized before taking them for further experiments. Potassium dichromate and other chemicals used for these tests were of analytical reagent grade and were obtained from standard sources.

3. Method A known weight (e.g. 2.0 g of absorbent) was equilibrated with 100 ml of the chromium solution of known concentration in 250 ml glass flask at room temperature (250C) .Chromium solution was prepared by dissolving the potassium dichromate (K2Cr2O7) in distilled water. Fresh dilutions were used for each study. The pH of Chromium solution was adjusted with a 0.1M HCL/0.1M NaoH solution. The time of each experimental was kept at 30 min. These flasks then were shaken on the shaker at 400 rpm. The samples were filtered through filter paper. The concentration of the samples was analyzed in a spectrophotometer (JENWAY 6305 UV/Vis model) using 1,5- diphenylcarbazide as the complexing agent at the wavelength of 540 nm [2]. The Cr(VI) loadings on sorbents were computed based on mass balance through loss of metal from aqueous solution. Effect of various pH; temperature; dose 1, 2, 3, 4 and 6 g/100 ml of solution ; contact time 5, 10, 15, 30, 40 min; initial concentration 0.5,1,2,4,5 ppm; particle size mesh>30, mesh<30, mesh>20; agitation speed 50, 100, 300, 400, 700 rpm were studied. The adsorption capacity was calculated by the Langmuir, Freundlich, and Temkin isotherm.

4. Results and Discussion 4.1. Effect of contact time Fig. 1 shows the adsorption of Cr(VI) by sawdust and activated sawdust, as a function of time. The experiments were carried out under the conditions of 25°C, particle size of <30 mesh, with 2 g of adsorbent in 100 ml of chromium solution and Initial Cr(VI) concentration 5 mg/l . The experiments showed that the removal rate occurs quickly, seemly reaching equilibrium within the first fifteen minutes of adsorption. Further increase in contact time did not show an increase in biosorption.

4.2. Effect of initial Cr (VI) concentration The effect of Cr(VI) concentration on the sorbent by varying the initial Cr(VI) concentration (0.5, 1, 2, 4 and 5 mg/l) for a time interval of 30 min. has been shown in Fig1 The percentage removal was decreased with increase in Cr(VI) concentration. At low concentrations the ratio of available surface to the initial Cr(VI) concentration is larger, so the removal becomes independent of initial concentrations. However, in the case of higher concentrations this ratio is low, the percentage removal then depends upon the initial concentration. From the results, it is revealed that within a certain range of initial metal concentration, the percentage of metal adsorption on absorbent is determined by the sorption capacity of the absorbent.

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4.3. Effect of Adsorbent Dose The effect of adsorbent dose on Cr (VI) uptake was investigated by varying the adsorbent dose (1, 2, 3, 4 and 6 g/100 ml) for a time interval of 30 min. Experimental results showed that the percentage removal Cr (VI) increases with the increasing amount of adsorbent up to 3g. This can be explained by the fact that the more the mass increases, the more the contact surface offered to the adsorption of chromium becomes important.

4.4. Effect of pH The pH of the aqueous solution is an important controlling parameter in the adsorption process. As results show, adsorption of Cr (VI) was higher at lower pH and decreased with increasing pH (Fig. 2). And the optimal initial pH was observed at pH 2.0. The dominant  2 2 chromium compound within the solution at pH=2 is HCr O4 (Cr O4 and also Cr2O7 exists). Removal of Cr(III) at pH=2 is zero while its removal percentage is very high at pH=5 where as removal percentage of Cr(VI) is significantly low. This shows that the pH of the solution is a very important parameter for the removal of Cr(VI) which is the toxic form of the chromium metal. At pH=2, due to the excess amount of H+ ions within the medium, the active site on the absorbent positively charged. This causes a strong attraction between these sites and negatively charged HCrO4- ions;     OH 2  HCrO4  OH 2 (HCrO4 ) (1) At low pH values active sites are positively charged. Therefore negative metals adsorption increases significantly. When pH value increases, surface of the adsorbent becomes the neutral and a decrease in the adsorption is observed. When the adsorbent surface is negatively charged, adsorption decreases significantly. This behavior is specific to the chromium ions and it is different for the divalent metals. Chromium ions release hydroxide ions to the solution instead of proton [12].

3.5. Effect of Temperature The adsorption of Cr(VI) at different temperatures shows an increase in the adsorption capacity when the temperature is increased (Fig.4). This indicates that the adsorption reaction is endothermic in nature. The enhancement in the adsorption capacity may be due to the chemical interaction between adsorbates and adsorbent, creation of some new adsorption sites or the increased rate of intraparticle diffusion of Cr(VI) ions into the pores of the adsorbent at higher temperatures . Kinetic energies of chromium ions were low at low temperatures. As a result, it is a very difficult and time-consuming process for ions to reach the active sites on the adsorbent. Increase in temperature causes increase in the mobility of the ions. If temperature is further increased, the kinetic energies of chromium ions become higher than the potential attractive forces between active sites and ions. The standard Gibb‘s energy was evaluated by 0 G  RT ln K C (2) The equilibrium constants Kc was evaluated at each temperature using the following relationship

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C Ae KC  (3) Ce where CAe is the amount adsorbed on solid at equilibrium and Ce is the equilibrium concentration. The other thermodynamic parameters such as change in standard enthalpy (ΔHo) and standard entropy (ΔSo) were determined using the following equation: S 0 H 0 ln K   (4) C R RT ∆Ho and ∆So were obtained from the slope and intercept of the Van‘t Hoff‘s plot of lnKc versus 1/T as shown in Fig. 3 Positive value of ∆Ho indicates that the adsorption process is endothermic. The negative values of ∆Go reflect the feasibility of the process and the values become more negative with increase in temperature. Standard entropy determines the disorderliness of the adsorption at solid–liquid interface.

4.6. Effect of Particle Size The effect of particle size on Cr(VI) sorption capacity of sawdust and activated sawdust of aspen has been shown in Fig.5 The removal of Cr(VI) ions at different particle sizes showed that the capacity of chromium adsorption at the equilibrium increased with the decrease in particle sizes. The relatively higher adsorption with smaller adsorbent particle may be attributed to the fact that smaller particles yield large surface areas and indicate that chromium ion adsorption occurs through a surface mechanism. It was also noticed that there is a tendency for a smaller particle to produce shorter time to equilibration.

4.7. Effect of Agitation Speed Biosorption studies were carried out with a magnetic shaker at ambient temperature. Cr(VI) solution was 5 ppm. The agitation speed varied from 50 to 700 rpm. The biosorption rate increased because of increasing kinetic energy of Cr(VI) particles. Basically, the removal of Cr(VI) is rapid but it gradually decreases with the increase of agitation speed, and the perecent removal of Cr(VI) of solutions were not changed after 300 rpm; therefore, Cr(VI) adsorption efficiency was maximal at 300 rpm.

4.8. Adsorption Isotherm Adsorption equilibrium data were fitted to the Langmuir, Freundlich and Temkin isotherms. Langmuir isotherm is based on the monolayer adsorption of chromium ions on the surface of absorbent sites and is expressed in the linear form[1]. Ce 1 Ce   (5) x / m KVm Vm where Ce is the equilibrium solution concentration, x/m the amount adsorbed per unit mass of adsorbent, m the mass of the adsorbent, Vm the monolayer capacity, and K is an equilibrium constant related to the heat of adsorption by equation: q K  K  exp( ) (6) 0 RT

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 where q is the heat of adsorption. Freundlich isotherm describes the heterogeneous surface energies by multilayer adsorption and is expressed in linear form as[1] x 1 Log  LogK  LogCe (7) m f n where Kf and 1/n are Freundlich constants related to adsorption capacity and intensity of adsorption, and other parameters are the same as in the Langmuir isotherm. The term log(x/m) can be plotted against logCe with slope 1/n and intercept log Kf. Temkin isotherm based on the heat of adsorption of the ions, which is due to the adsorbate and adsorbent interactions taken in linear form, is given by[8]: x RT RT  ( )LnA ( )LnCe m b b (8) RT  B b where A (l/g) and B are Temkin constants. The data obtained from the adsorption experiments conducted at 25(±2)°C were fitted to Eqs. (5) , (7) and (8), linear plot (not shown) were obtained for Ce/(x/m) versus Ce, Log(x/m) versus Log(Ce) and x/m versus LnCe. The isotherm parameters for three equations along with the values of coefficient of correlation (R) are presented in Table 1. Table 1 shows that the data better fits to Freundlich equation than Langmuir and temkin equations , which is indicated from the higher values of R.

5. Conclusion  The present study showed that lignocellulosic solid wastes such as sawdust can be used as effective adsorbents for removal of Cr(VI) from wastewater. These natural wastes are available in large quantity and can be used as an alternative to existing commercial adsorbents for removal of Cr(VI).  The adsorption process is a function of the contact time, initial concentration, pH , temperature, agitation speed, absorbent dose and particle size.  The amounts of Cr(VI) adsorbed increased with increase in dose of both adsorbents and their contact time. Adsorption of Cr(VI) is found to be effective in the lower pH and found to be maximum at pH 2.0. Increase in adsorption capacity with rise in temperature reveals that the adsorption is chemical in nature and the process is endothermic, which is confirmed by the thermodynamical parameters evaluated. Removal of Cr(VI) increased with increasing adsorbent dose.  In conclusion, the Freundlich isotherm fits the data better than the Langmuir and Temkin isotherms.

References 1. Aliabadi, M., Morshedzadeh, K., Soheyli, H., 2006. Removal of hexavalent chromium from aqueous solution by Lignocellulosic Solid Wastes, Int. J. Environ. Sci.Tech., 3(3): 321-325. 2. Arthur, I. vogel, D.Sc. (Lond.), D.I.C., F.R.I.C, 1998, A Text-Book of Quantitative Inorganic Analysis Including Elementary Instrumental Analysis, 791-792

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3. Cieslak-Golonka, Maria., 1996. Toxic and mutagenic effects of chromium (VI). Polyhedron, 15(21): 3667-3918. 4. Dakiky, M., Khamis, M., Manassra, A.,. and Mereb, M.,2002. Selective adsorption of chromium (VI) in industrial wastewater using low-cost abundantly available adsorbents. Advances in Environmental Research, 6(4): 533-540. 5. EPA (Environmental Protection Agency).,1990. Environmental Pollution Control Alternatives. EPA/625/5-90/025, EPA/625/489/023, Cincinnati, US 6. Iqbal, M., Saeed, A., Akhtar, N., 2002. Petiolar, felt-sheath of palm: a new biosorbent for the removal of heavy metals from contaminated water. Bioresource Technology, January, 81(2): 153- 155. 7. Kadirvelu, K., Thamaraiselvi, K., Namasivayam, C., 2001. Adsorption of Nickel(II) from aqueous solution onto activated carbon prepared from coir pith, Sep. Purif. Technol. 24, 497–505. 8. Karthikeyan, T., Rajgopal, S., Lima Rose Miranda, 2005. Chromium (VI) adsorption from aqueous solutionby Hevea Brasilinesis sawdust activated carbon, J. hazard. Mater. B124 (2005) 192-199. 9. Mahvi, A.H., Naghipour, D., Vaezi, F. ,Nazmara, SH., 2005. Teawaste as an adsorbent for heavy metal removal from industrial wastewaters. American Journal of Applied Sciences, 2(1): 372-375. 10. Marshall, W.E. and Champange, E.T., 1995. Agricultural byproducts as adsorbents for metal ions in laboratory prepared solutions and in manufacturing wastewater. Journal of Environmental Science and Health - Part A Environmental Science and Engineering, 30(2): 241-261, 1995. 11. Melo, M. and Ď'souza. S.F., 2004. Removal of chromium by mucilaginous seeds of Ocimum Basilicu. Bioresource. Technology, 92(2): 151-155. 12. Muradiye, UYSAL., Irfan, AR.,2006. Removal of Cr(VI) from industrial wastewaters by adsorption, J. hazard. Mater. 13. Namila, D., Mungoor, A., 1993. Dye adsorption by a new low cost material Congo red-1, Indian J. Environ. 13, 496–503. 14. Teixeria, T.,, Cesar R., Zezzi, A., Marco,A., 2004. Biosorption of heavy metals using ricemilling by-products. Characterisation and application for removal of metals from aqueous solutions. Chemosphere, 54(7): 905-915.

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100

80

60

40

%adsorbtion 20

0 5 10 15 20 25 30 35 40 45

time(min)

sawdust activated sawdust

Fig.1. percent removal of Cr(VI)(5ppm)Vs. time

100 90 80 70 60 50 40

30 %adsorbtion 20 10 0 0 1 2 3 4 5 6

initial concentration

sawdust activated sawdust Fig. 2. Effect of initial Cr (VI) concentration

100 90 80 70 60 50 40

30 %adsorbtion 20 10 0 1 2 3 4 5 6 7 dose absorbent

sawdust activated sawdust

Fig.3. Effect of dose on Cr (VI) adsorption

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100 90 80 70 60 50 40

%adsorbtion 30 20 10 0 1 2 3 4 5 6 7 8 9 PH

activated sawdust sawdust

Fig.4. Effect of pH on Cr (VI) adsorption

5 4 3

2 Ln(Kc) 1 0 0.003 0.00305 0.0031 0.00315 0.0032 0.00325 0.0033 0.00335 1/T(1/K)

saw dust activared saw dust

Fig.5. Vant Hoff' s plot at ambient temperature

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PETROGENETIC EVOLUTION LATE CENOZOIC VOLCANISM OF THE LESSER CAUCASUS

A.A. VELIEV *, M. Y. GASANKULIYEVA*, N.A. IMAMVERDIYEV **, G.J. BABAYEVA*

* Institute of Geology of Azerbaijan Academy of Sciences, Az 1143 Baku, av. H. Javid 29a

** Baku State University, Az 1148 Baku, st. 23 Z. Khalilov, Baku State University, Geology department E- mail: [email protected]

Abstract In the article analyze the nature of the substrate the Late collision volcanism of the Lesser Caucasus and the origin of volcanic associations. Revealed that a common feature for most of the Neogene- Quaternary volcanic rocks of the Lesser Caucasus is a relative enrichment in light REE and lithophile elements and weak depletion for heavy rare earth elements, as well as Nb, Ta, Hf. It is concluded that the rocks of the Neogene andesite-dacite-rhyolite and Upper Pliosen-Quaternary trachybasalt- trachyandesite associations melted from sources garnet (3-10% and 1-2,5%, respectively). The presence of adakites rocks of magmatic products in late collision after the cessation of subduction zones can be associated slab-melts. Upper Pliocene-Quaternary rhyolite-dacite magma rocks were granite-metamorphic layer of metamorphosed in the amphibolite and granulite facies rocks metamorphism. The rocks of andesite-dacite-rhyolite and trachybasalt-trachyandesite associations due to a single process of assimilation and fractional crystallization (AFC). The average rocks both associations may have formed during the fractionation of basalt in the absorption of a significant amount of the acid melt.

Interdiction One of the pressing problems of conflict zones of the study is to elucidate the evolution of magmatism occurring within them. Display magmatic associations, their petrochemical charact-erristics reflect the specificity of their manifestations, as well as the development of magmatism from magmageneration to the evolution of magmatic melt in the earth's crust. Materials on the distribution of rare and rare earth elements in different rock types, as well as other of their geochemical and petrological characteristics allow using the well-known models to analyze some aspects of the processes of birth, evolution and crystallization of deep magmatic melts. In this sense, the study of the geochemical characteristics of mantle and crystal sources of magmatism that have come out in a conflict like the continent - the continent is quite topical. Therefore, the study late collision volcanism of the Lesser Caucasus is a theoretical and practical interest.

Research Methods This article used data from the Neogene-Quaternary volcanism of the Azerbaijan part of Lesser Caucasus based on the authors.Chemical analysis of rocks was determined by the Institute of Geology of Azerbaijan Academy of Sciences flyurotsentnym X-ray method. Rare and rare-earth elements in Geological and Geochemical Bronitsk expeditions in Russia, the analytical laboratory (LTD) of Canada by Inductively Plasma Spectrometry (ICP). Microprobe analysis of mineral composition written in IGEM Academy of Sciences of Russia and all in Sant Peterburg. Measuring the isotopic composition of He performed in

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Geochemistry Institute of Academy of Sciences Russia, also used the data Sr and Nd [7-9], performed on the material of Armenia and Georgia.

Petrochemical features Andesite-dacite-rhyolite association. For silica rock associations form a continuous series of andesites (SiO2 > 60%) to rhyolites (Table 1), and the ratio (Na2O + K2O)-SiO2 [10] are the rocks of normal alkalinity . (some breeds – mid alkaline) in the diagram K2O-SiO2 [11] most of the samples falls within the high K calc-alkaline series (Fig. 3), the diagram FeO */ MgO-

SiO2 composition points are located in the field calc-alkaline series . The rocks of this association are characterized by different contents of major elements. In volcanic rocks with increasing SiO2 content decreases TiO2, Al2O3, Fe2O 3, MgO, CaO, P2O5, due to fractionation of titanomagnetite, clinopyroxene, plagioclase, and possibly apatite.

Weak rates increased content of K2O. Na2O is distributed evenly, but also an increase in the number of its slower rate . The reason for this pattern may be a potassium feldspar in the more acidic varieties of rocks. Rhyolitic association. Rocks associations, in contrast to the previous rock associations, are characterized by ultra-structure and high alkalinity. There is approximately equal ratio of

Na2O and K2O and low contents of CaO, MgO, FeO (Table 1). In the normative composition of the rocks are calculated high content of salic components of quartz, feldspar and corundum. Trachybasalt-trachyandesite association. For silica rock associations form a continuous series from basalts to andesites (Table 1) and belong to the mildly alkaline series .In the diagram K2O-SiO2 composition points fall in the region high -K calc-alkaline and shoshonite series .In rock associations in the range of "trachybasalt-basaltic trachyandesite" with increasing silica content of TiO2, MgO, Fe2O3, CaO, P2O5 is reduced to a large extent, the contents of the same Al2O3, Na2O decreases the slow pace . In the transition to trachyandesites content of these elements varies in a narrow range .The maximum content of MgO is observed in trachybasalts and alkaline olivine basalts and varies from 3,97 to 6,81% (Table 1), and the coefficient of Mg (M) from 56 to 71. In subsequent decrease differentiates the content of MgO and "M". In the normative part of some mildly alkali olivine basalts and trachybasalts calculated normative nepheline and olivine, in more acidic differentiates calculated hypersthene and quartz. Normative and mineral composition reflects the characteristic feature of the association: transition nepheline-normative, olivine containing mildly alkaline rocks to hypersthene-normative and sometimes quartz-bearing alkaline rocks.

Geochemical features The concentrations of rare and rare earth elements in rocks of andesite-dacite-rhyolite association as a whole regularly changing. Thus, the concentration of lithophile elements increases from andesite to rhyolites (Rb from 44 to 128 ppm, Th 6 to 24 ppm) (Table 1). From the coherent elements in increasing the acidity of rocks in general, the content of V, Cr, Co, Ni decreases. These elements are the same Sr form of silica negative dependence. Positive, but more vague correlation with silica form the content of Y and highly charged elements (HFSE - Nb, Zr, Hf) (Fig. 7). The above features show the leading role of crystallization differentiation in the association of rocks. Comparison of impurity elements rocks andesite- dacite-rhyolite association and the primitive mantle [12] the reduced content of Nb and Ta

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 and elevated levels of lung large ionic lithophile elements (Rb, Ba, Th, La, Ce, Sr) (LILE). Thus, in relation to the primitive mantle there is a maximum Rb, Ba, Th, La, Ce, Sr, and negative Ta-Nb anomalies. It is conceivable that this feature brings these rocks with supersubduction volcanic associations. As seen from Figure 8 the distribution of trace elements for andesite, quartz latite, dacite and rhyodacite are repeated in general terms, indicating that their genetic identity. From the same type of rocks of andesite-dacite-rhyolite association rocks rhyolite associations differ depleted femic components, a lower content of iron group elements, highly charged elements and enrichment of ore elements in the earth crust, as well as lithophile elements (Pb, Th, U). The distribution of trace elements normalized to primitive mantle for the rhyolite, showed that, like the rock of the previous association, rhyolite is enriched in LILE and depleted in highly charged elements . However, the nature of the schedule rhyolite is different from the schedule rocks previous association and is close to the top of the crust [13], suggesting a different genesis of the rocks of this association. In the rocks trachybasalt- trachyandesite association occurs in about the same pattern as in the rocks of andesite-dacite- rhyolite association, but more clearly. Rocks of this association inherent to the high content of Rb, Ba, La, Sr (Fig. 8), as well as high values of La/Yb, La/Sm relations. Compared with the composition of primitive mantle [13] alkaline basalts are enriched in most LILE and some highly charged elements: Rb, Ba, Th, La, Ce, Sr, Zr . Geochemical data for this association show that the diversity of species association is due mainly to fractional crystallization. This is evidenced by: 1) with increasing SiO2 content decreases compatible elements (Cr, Ni) and increasing concentrations of incompatible elements (Rb, Th, U) (Fig. 9) due to fractionation of olivine and clinopyroxene, and 2) revealed clear positive correlation connection LREE with phosphorus, calcium and fluoride, due to the concentration of light rare earth elements in apatite (the distribution coefficients of REE for apatite is 10-100). These data indicate that fractional crystallization is particularly important for trachybasalts and basaltic trachyandesites. In the process of differentiation of the content of trace elements naturally varies depending on the composition of the melt, its temperature, as well as the composition and crystal-chemical properties of rock-forming minerals. Content and types of spectra of these elements of the breed trachybasalt-trachyandesite associations of the Lesser Caucasus are close to the rocks of oceanic islands and the rift zones formed from the enriched mantle source. Similarity of plots the distribution of elements on the primitive mantle may indicate comagmatic members of the association.

Isotopic composition For the Neogene - Quaternary rocks of the Lesser Caucasus, we have obtained for the 7 samples of volcanic rocks and their nodules isotopic compositions of He (Table 2). The highest ratio of 3 He/4 He (3He/4He = 0,93 × 10-5) is characteristic for alkali olivine basalts, which brings them to the mantle derivatives. Approximately the same value is obtained for amphibole megacrysts from trachyandesite approaching the isotope ratios of primary helium mantle reservoirs (1-5 × 10 -5) [14] and to the gases carbon sources, the most active areas associated with manifestations of modern volcanism of the Lesser Caucasus (3He/4He = 10-5) [15]. A fractional difference between the rocks of trachybasalt-trachyandesite association, their nodules, as well as andesite of andesite-dacite-rhyolite association have lower values of

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 helium isotopes (Table 2). These data indicate that differentiate the first association, incorporation and andesite second association crystallized in the earth crust.

Table 2. Isotopic composition He in Late Cenozoic rocks of the Lesser Caucasus No Rocks and minerals 3He/4He·10-6 4He·10-6 samples 132 Alkaline olivine basalte 9,29 (±1,46) 0,604 (±0,006) 21 Trachybasalte 1,76 (±0,27) 2,70 (±0,03) 13 Trachyandesite 1,05 (±0,18) 1,54 (±0,02) 15 Andesite 0,924 (±0,162) 2,36 (±0,02) Nodules 25-в Pyroxsenites 3,33 (±0,49) 3,43 (±0,03) 13-м Megacryste amphybole 9,39 (±1,42) 2,90 (±0,03)

Unfortunately, isotopic data Sr, Nd of the Azerbaijan part of Lesser Caucasus absent. There is anecdotal evidence about the Armenian and Georgian part of the Lesser Caucasus. I.V. Chernyshev, and his co-workers [8, 9] determined the absolute age of alkali basalts Javakheti Plateau, we propose a new version of the geochronological scale of the Neogene-Quaternary magmatism of the Caucasus. Dan precise absolute age of rhyolite volcanism for different volcanic highlands of the Lesser Caucasus [7]. Data above authors argue that the dominant role in the petrogenesis of lavas played by processes of fractional crystallization and contamination of the parent melts geochemically distinct from them, crustal matter [9]. A sour rhyolite volcanism developed in the context of tectonic and thermal activity of mantle lesions and relationship with the processes of local anatexis in the lower crust zones of metamorphism [7]. Our petrology and geochemistry data confirm these findings.

Discussion of results This section discusses the nature of the mantle substrate region under study, as well as the origin of each of volcanic associations.

Mantle sources These isotopic composition of Sr and Nd for late Cenozoic volcanic rocks of the Lesser Caucasus show that the primary melts to produce a mantle sources. Acid rock has mostly crustal origin. There have been offset mantle and crustal magmas. In general, this assumption is acceptable for the Azerbaijan part of the region. A common feature for most of the Neogene-Quaternary volcanic rocks of the Lesser Caucasus is a relative enrichment in light REE and large lithophile elements (Rb, Ba), and weak depletion for heavy rare earth elements, as well as Nb, Ta, Hf. These geochemical data confirm the presence of restite of garnet in the magmatic source for the andesite-dacite-rhyolite and trachybasalt-trachyandesite associations. In addition, we believe in the petrogenesis of Late collision basaltoids important role played mantle substance metasomatically processed by previous subduction processes, as evidenced by the relatively high oxidized rocks associations. (Ce/Yb) MN - Yb MN shows the calculated line of equilibrium partial melting of garnet peridotite with different content of garnet. Calculated trends melting portions of garnet peridotite, containing 2,5, and 4% garnet, borrowed from [16]. As seen from Fig.10, composition points of rocks of andesite-dacite-

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 rhyolite associations are in the range of values with a relatively high degree of melting (3- 10%) mantle source containing 4% garnet. Lineups alkali basaltoids trachybasalt- trachyandesite association on this chart are in the range of values with a low degree of melting (1-2,5%) garnet peridotite and, apparently, mantle source was more metasomatized (17, 18). It can be assumed that a lower degree of melting of the mantle of the substrate led to the association of basaltic melt at high alkalinity and a significant enrichment of the melt K, P, F, Ba, LREE due priority to the melting of phlogopite, apatite, amphibole, which are the main carriers of these elements. Fig.10. Normalized to primitive mantle [12] the ratio of Ce / Yb- Yb in the Late Cenozoic basalts and andesites of the Lesser Caucasus. Calculated trends melting portions of garnet peridotite, containing 2,5, and 4% garnet [16]. The numbers along the curves - the percentage of melting. Legend: 1 - andesites, andesite-dacite-rhyolite association, 2 - alkaline basalts trachybasalt-trachyandesite association. At present, the association of these volcanic rocks are often associated with the association of subduction ―windows‖ (slab-window) and see the result of decompression melting of asthenospheric diapir. These volcanics differ from typical subduction magma and have geochemical characteristics of OIB sources. They are described for the active continental margin of North America, Philippines, Kamchatka, East Sikhote-Alin .For collision volcanics this idea is developed [24-28]. Such rocks are called adakites. They are characterized by high ratio LREE / HREE and are formed by melting of garnet containing material (eclogite) oceanic plate. Note that we also do not deny the delamination subduction lithospheric slab in the association of Late Cenozoic volcanic rocks of the Lesser Caucasus . This is evidenced Seismic and some of petrology and geochemistry data. Part of Late Cenozoic andesite and dacite of the Lesser Caucasus can be considered derivatives adakites melts. They (La/Yb)n varies from 17,5 to 26,4, the concentration of Y from 6 to 13 ppm, Yb from 1,2 to 1,8 ppm. Figure Sr/Y-Y majority of species fall into the field adakites [19] . Thus, it is found that the rocks of the Neogene andesite-dacite-rhyolite and Upper Pliocene-Quaternary trachybasalt- trachyandesite association smelt garnet sources at a depth of not less than 60-80 km [5, 30]. Not be excluded on the association of andesite melting subduction oceanic crust [9]. As Upper Piocene-Quaternary acidic volcanic rocks, as shown by the full range of studies and published isotopic data for the region, the source of rhyolite-dacite magmas could serve as a rock granite-metamorphic layer, metamorphosed to amphibolite and granulite facies metamorphism. The high concentrations of K, Li, Rb, Cs, U, Th, Rb and low Sr, Ba, Zr, Ti and light lanthanides, the presence of a deep negative Eu - anomalies may indicate relatively low levels of fusion substrate, in which a significant portion of plagioclase and accessories remained in the restite. The eastern part of the Lesser Caucasus (Vardenis and Syunik uplands) 87 Sr / 86 Sr are 0,70444-0,70811 [7].

Fractional crystallization Petrochemical data show that the association of andesite-dacite-rhyolite and trachybasalt- trachyandesite association of fractional crystallization occurred. Thus, in the rocks of andesite-dacite-rhyolite association with increasing silica content decreases femic rock- forming oxides, increasing the content of incompatible elements due to fractionation of dark- colored minerals and feldspars. However, fuzzy trends show the influence of processes of assimilation and crustal contamination on the association of these rocks. Thus, an attempt to

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 get out of andesitic dacites and from dacitic rhyolites by fractionation of clinopyroxene, amphibole, biotite, magnetite and feldspar failed. Therefore, as will be shown below, apparently, the association of these rocks is dominated by a single process of AFC, i.e. assimilation and fractional crystallization. We believe that fractional crystallization played a leading role in the association of rocks trachybasalt-trachyandesite association. This is evidenced by the behavior of a number of rock-forming trace elements. For example, a change in slope of trends MgO-SiO2, TiO2-SiO2, Ni-SiO2 in the field trachyandesite explained by fractionation of olivine, clinopyroxene, magnetite (Fig. 9). Past balance calculations on a computer showed that the evolution of the melt occurred as a result of changes in the composition and quantity of rock-forming minerals. The results of balance calculation of fractional crystallization of alkaline olivine basalt-trachybasalts showed that the latter is obtained by fractionation of 19,8% Cpx, 57,6% Pl (An65), 15,0% Ol (Fo 84) and 7,6% Mt. The absolute and calculated values for major and trace elements in the whole match (ΔR2 = 0.507). The degree of fractionation at the same time is about 61%. D – Bulk partition coefficient (are taken from [5, 31]) Fractionation of the above minerals, and amphibole leads to further differentiates associations and the result is a continuous differential series - trachybasalt-basaltic trachyandesite- trachyandesite. Possible further differentiation of the melt to the trachytes, trahyriodasites that is, for example, in a large polygenic volcano Ishyhly. Although, FC simulation of least squares using the basic rock-forming oxides and some trace elements gives good results, the majority of trace elements do not conform to this model. Thus, the content of LREE and HREE for different types of rocks vary in narrow limits. At Harker diagrams micronutrients -

SiO2, where not all elements give a clear linear dependence. This suggests their association by other mechanisms, too.

Crust contamination We have previously shown that the role of crustal contamination in the genesis of Late Cenozoic volcanic rocks of the Lesser Caucasus is negligible [5]. In other works [32, 33] speculation about a significant transassociation of the primary magmas of crustal processes. We obtained the last petrogeochemical data suggest involvement in petrogenesis Late Cenozoic volcanic enriched mantle source (lithospheric mantle) and a significant contribution to processes of crustal contamination. The calculations show AFC - a model of crustal material required for the appropriate changes to the source mantle composition of rocks trachybasalt-trachyandesite association can be achieved during the fractionation of basalts (degree of fractionation of F = 0,5-0,6) with the absorption of a large number of acid melt (the ratio of assimilation rock and cumulates r = 0,3-0,5) . A similar pattern is observed for rocks of andesite-dacite-rhyolite association, but this shift is achieved with a high degree of fractionation (F = 0,7-0,9) and with a large number of acidic substances (r = 0,6). Obviously, with such volumes of assimilation acidic substances are not stored petrochemical characteristics of the primary rocks (andesites and basalts). Therefore Harkers figures are not observed clear trends. Below are the results of AFC - modeling for rocks trachybasalt- trachyandesite association. As seen from Table. 4, the intermingling rhyolite and basic rocks (alkaline olivine basalts and trachybasalt) may be formed basaltic trachyandesite and

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010 trachyandesite. Summarizing the above data, the association of Late Cenozoic volcanic series of the Lesser Caucasus can be represented as follows. Within the Lesser Caucasus in the late Cenozoic volcanism expressed high-K calc-alkaline, mildly alkaline and partly alkaline associations. In Neogene time (Upper Miocene-Lower Pliocene), with decompression occurs anatexis metasomatized mantle and lower strata of basalt layer at a sufficiently large depth, which determines the enrichment of these melts with alkali, alkaline earth and light rare earth elements. This process resulted in association of basaltic melts, enriched in alkalis. Perhaps such a melt was formed at low degrees of partial melting (3-10%) of garnet peridotite or eclogite. We can assume that it corresponds subduction oceanic crust. In the future, as a result of growing tension mantle melts penetrated the upper layers of the earth crust, where it mixes basic and acid magma, with the association of hybrid andesite, andesite-dacite lavas. Progressive cooling of the deep source magma origin may be the cause of education dike fields in the region studied and possibly fractured outpouring mildly alkaline volcanism observed in the other parts of the Lesser Caucasus. Due to additional heating and the flow of volatiles formed fairly large volcanoes of calc-alkaline composition of Neogene age. Then Upper Pliocene-Quaternary formed bimodal volcanism. Thus, the temporal spatial conjugation of crustal and mantle magmatism led to the introduction of mantle melts, under conditions of tension in the lower crust, which resulted in its melting and the association of acidic volcanic rocks rich in radiogenic Sr and Nd (rhyolite association). Simultaneously, in this situation, a change of scenery compression and tensile contributed to the development rifts depressions, arching and exercise slow differentiated and undifferentiated volcanic (trachybasalte- basaltic trachyandesite-trachyandesite and basanite- tefrite series). Thus, the evolution of the melt in the earth crust dominated by a single process of AFC (assimilation and fractional crystallization). As the fractionation rare elements, intermediate rocks can be formed by mixing trachybasaltic and rhyolite melts.

Conclusions 1. In Late Cenozoic stage of development of the Lesser Caucasus formed high-K calc - alkaline, mildly alkaline and alkaline part series. 2. The common feature for most of the Neogene-Quaternary volcanic rocks of the Lesser Caucasus is a relative enrichment in light REE and large cation lithophile elements and weak depleted for heavy rare earth elements, as well as Nb, Ta, Hf. 3. The Neogene andesite-dacite-rhyolite and Upper Pliocene-Quaternary trachybasalt- trachyandesit associations melted from sources garnet (3-10% and 1-2,5%, respectively). Not excluded in the association of andesites subduction melting of oceanic crust. Presence adakite rocks of magmatic products in late collision after the cessation of subduction zones may be associated slab-melts. Source Upper Pliocene-Quaternary rhyolite-dacite magma rocks were granite-metamorphic layer, metamorphosed in the amphibolite and granulite facies metamorphism. 4. The andesite-dacite-rhyolite and trachybasalt-trachyandesite associations due to a single process of assimilation and fractional crystallization (AFC). Medium rocks both associations could be formed during the fractionation of basalt in the absorption of a significant amount of the acid melt.

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Referens 1.Koronovsky N.V., Demina L.I. Collision stage of the Caucasian sector Alpine orogen: geodynamics and magmatism / / Geotectonics, 1999. No 2. C.17-35. 2.Karyakin U.V. Geodynamics of the formation of volcanic complexes of the Lesser Caucasus. M.: Nauka, 1989. 150 pp. 3.Rustamov M.I. South Caspian Basin, geodynamic events and processes. Baku: Nafta-Press, 2005. 245 pp. 4.Kashkay M.A., Khain V.E, Shihalibeyli E.SH. To a question about the age of Kelbajar volcanic strata Dokl Azerb.SSR, 1952. No 6. p.285-289. 5.Imamverdiev N.A. Geochemistry of Late Cenozoic volcanic complexes of the Lesser Caucasus. Baku: Nafta-Press, 2000. 192 pp. 6.Kashkay M.A., Mamedov, A.I. Perlite, obsidian, pehshteyny and mineralogical-petrographical and physico-chemical characteristics. Baku: AN Az. SSR, 1961. 181 pp. 7.Karapetian S.G., Jrbashian R.T, Mnatsakanian A..Kh. Late collision rhyolitic volcanism in the north- eastern part of the Armenian Highland / / Journal of Volcanology and Geothermal Research, 2001. V. 112. p.189-220. 8.Lebedev V.A., Chernyshev I.V., Bubnov S.N. The new version of the geologic time scale Neogene- Quaternary magmatism of the Caucasus / / http:www.geology.ru. 2008. 9.Lebedev V.A, Bubka S.N., Chernyshev I.V., Chugai A.V., Duduari O.Z., Vashakidze G.T. Geochronology and features of the genesis of subalkaline basalt lava rivers Javakheti Plateau, the Lesser Caucasus: K-Ar and Sr-Nd isotopic data / / Geochemistry, 2007. No 3. p.243-258. 10.Le Bas MJ, Le Mitre R.W, Streckeisen A., Zanettin B. A chemical classification of volcanic rocks based on the total alkali-silica (TAS) diagram / / J. Petrol. 1986. V.27. p.745-750. 11.Pecerillo A., Taylor S.R. Geochemistry of Eocene calc-alkaline volcanic rocks from the Kastamonu area, Northern Turkey / / Contrib. Miner. Petrol. 1976. V.58.p.63-81. 12.Sun S.-S., McDonough W.E. Chemical and isotopic systematic of oceanic basalts: implications for mantle composition and processes / / Magmatism in the ocean Basins. Ed. Sunders A.D., Norry M.J. Geol. Soc. Lond. Spec. Publ. 1989. V.42, p.313-345. 13.Taylor S.R., McLennan S.M. The geochemical evolution of the continental crust / / Rev. Geophys. 1995. V.33. p.241-265. 14.Mamyrin B.A, Tolstikhin IN Helium Isotopes in Nature. M.: Energoizdat. 1981. 222 pp. 15.Matveeva E.S,, Tolstikhin I.N,, Yakutseni V.P. Isotope helium gas criterion of origin and to identify areas neotektogeneza (for example, the Caucasus) / / Geokhimiya, 1978. No 3.p. 307-317. 16.Brandshaw T.K, Hawkesworth C.J, Gallagcher K. Basaltic volcanism in the Southern Basin and Range: no role for a mantle plume / / Earth and Planetary Sci. Lett. 1993. V.116. p.45-62. 17.Imamverdiev N.A. Physico-chemical conditions of crystallization Late Cenozoic volcanic formations of the Lesser Caucasus / / Petrology. 2003. T.11, 1, p.82-101. 18.Imamverdiev N.A. Geochemistry of rare earth elements Late Cenozoic volcanic series of the Lesser Caucasus / / Geochemistry, 2003. No 4. p.425-442.

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19.Defant M.J., Drummond M.S. Derivation of some are magmas by melting of young litosphere / / Nature, 1990. V.347. p.662-665. 20.Kelemen P.B. Genesis of the high Mg andesites and the continental crust / / Contrib. Mineral. Petrol., 1995. V.120.p.1-19. 21.Sajona FG, Maury RC, Pubeller M., Leterrier J., Bellon H., Cotton J. Magmatic source enrichment by slab-derived melts in a young post-collision setting, central Mindanao (Philippines) / / Lithos, 2000. V.54. p.173-206. 22.Martynov Y.A., Chaschin A.A., Simanenko V.P, Martynov A.Y. Danish Maastricht-andesite series of the eastern Sikhote-Alin: Mineralogy, geochemistry and petrogenesis of questions / / Petrology, 2007. V.15. No 3. p.295-316. 23.Fedorov P.I., Kovalenko D.V., Bayanova T.B., Serov, P.A. Early Cenozoic magmatism of the continental margin of Kamchatka / / Petrology, 2008. V.16. No 3. p.277-295. 24.Pearce J.A., Bender J.F., De Long, Kidd W.S.F. et al. Genesis of collision volcanism in Eastern Anatolia, Turkey / / J. Volcanol. Geotherm. Res. 1990. V.44. p.189-229. 25.Keskin M. Magma generation by slab steepening and breakoff beneath a subduction-accretion complex: an alternative model for collision related volcanism in Eastern Anatolia, Turkey / / Geophysical Research Letters, 2003. V.30. No 24. p.9-1-9-4. 26.Keskin M. Domal uplift and volcanism in a collision zone without a mantle plume: Evidence from Eastern Anatolia, / / http:www.mantleplumes.org/Anatolia.html.2005. 27.Keskin M., Genc S.C., Tuysuz O. Petrology and geochemistry of post-collisional middle Eocene volcanic units in North-central Turkey: Evidence for magma generation by slab breakoff following the closure of the Northern Neotethys ocean / / Lithos, 2008. V.20. p.1-39. 28.Ershov AV, Nikishin AM Recent Geodynamics of the Caucasus-Eastern African region / / Geotectonics, 2004. No 2. p.55-72. 29.Imamverdiev NA Delamination subduction lithospheric slabs as the cause of manifestation of Late collision volcanism of the Lesser Caucasus. / / Bulletin of the Baku University. Series of Natural Sciences, 2008. No 3, p.123-137. 30.Imamverdiev NA, Gasankulieva MJ, Veliyev AA Geochemistry of the Upper Pliocene-Quaternary volcanism of the Lesser Caucasus: petrogenesis, mantle source characteristics / / Proc.: "The scientific heritage of Academician MA Kashkai. View from the XXI century ". Baku. "Nafta- Press". 2007. p. 139- 152. 31.Rollinson H. Using geochemical data: evoluation, presentation, interpretation. UK: Longman Scientific and Technical. 1993. 352 pp. 32.Popov V.S., Semin, V.A, Nikolaenko Y.S. Geochemistry of the latest eruptions of the Caucasus and their origin. Proc.: Geochemistry of continental volcanism. M.: Nauka, 1987. p.143-231. 33.Ismail-Zadeh, A.D. Evolution of Cenozoic volcanism basite Lesser Caucasus. Abstract. diss. Doc. geological-mineralogical. Science. Tbilisi. 1990. 50 pp.

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