نشریه علوم دانشگاه خوارزمی
سال دهم شماره 2 (تابستان 1389)

The study of planktonic foraminifera of the Gurpi Formation in southwest of Firozabad(Aghar anticline) area led to recognition of eight biozones that include: Dicarinella asymetrica Zone (Santonian to Earliest Campanian), Globotruncanita elevata Zone (Early Campanian), Globotruncana ventricosa Zone (Mid to Late Campanian), Radotruncana calcarata Zone (Late Campanian), Globotruncanella havanensis Zone (Late campanian), Globotruncana aegyptiaca Zone (Late to Latest Campanian), Gansserina gansseri Zone (Latest Campanian to Early Maastrichtian), Contusotruncana contusa and Racemiguemblina fructicosa Zone (Early to Late Maastrichtian). In study area, the Gurpi Formation overlies the Ilam Formation with erosional disconformity and is overlain by the Pabdeh Formation with erosional disconformity. Based on distribution of morphotype groups of planktonic foraminifera, planktonic foraminifera per bentic foraminifera ratio(P/B) and content of carbonate, seven third-order sequences are recognized. Sequence boundries of Gurpi Formation with Ilam Formation at the base and with Pabdeh Formation at the top, are SB1, but other sequence boundries are SB2.

Due to high erosional sensitivity of marls, thousands of tons of fine grains sediments and clayare send to reservoirs of dams and artificial feeding stations annually. This process increases the expenses of filteration of drinkable water and forwards settlement of artificial feeding water strongly, Therefore, the study of different dimensions of marls is important for specialists and researchers. In this project, attempts were made to recognize effective variables of erosional features and some models were produced for classification and their erosional tye. Accordingly, 49 samples of marly soils belonging to 41 erosional points were taken and were send to laboratory for determinig of amount of physico-chemical variables. Also, characteristics of sampling place such as slope, Geographical situation, privilege of 7 parameter for soil surface factor and so on were noted. The test of artificial rain was done by kampHorst΄s rainfall simulator apparatus in the 41 mentioned points and 41 samples were taken and the amount of runoff and sediment of them were measured by simple method in the laboratory. Furthermore, the 7 samples of marls were analyzed by X-ray diffractometer and the 8 thin setions of marls and their accompaniment rocks were provided and studied by polarizing microscope. Then, the abnormal data were normalized by logarithm and afterwards the all data were evaluated by variance and discriminant analysis. Evaluation of relationship between measured variables and erosion features showed that pH is only variable whose amount makes a significant difference and is effective for recognition of erosion features and sensibility of fisher΄s linear discruminant functions for prediction of erosion features together with all chemical, all physical and all physico- chemical variables are orderly equal with 75.6%, 82.9% and 78%. This shows that the physical variables are more usefull than chemical and physico-chemical variables for prediction of erosiolal features. The finally,in this research, several fisher΄s linear functions were produced for prediction of erosional type of Hamedan marls through these analysis.

The Shadgan petroleum oil field located in Dezful Embayment is a symmetrical anticline with 23.5Km length and 6.5Km width in the Asmari top horizon. The field trend is similar the regional Zagros trend. Asmari reservoir consisted of two separated reservoirs. The aim of the present study is to construct stratigraphy and faults models, reservoir quality evaluation, fault impacts and oil volume determination using RMS software. To construct the structural model, faults and reservoir zones data will be applied to design reservoir geometry. Stratigraphic and fault models revealed that the faults passed through the reservoirs but have not affected on their relations. This fact is verified by different petroleum API in two reservoirs and their independent pressure variations as well during production period. With correlation of faults, porosity distribution and reservoir volume models, it was revealed the fault effects in the reservoir properties quality.

The design of appropriate, cost-effective remedial measures requires a clear understanding of the processes that are causing the landslide. This understanding require a detailed site investigation, a reconnaissance of the landslide as soon as possible after it's occurrence can allow important observations of the processes involved. A key step in analyses of soil slope stability is measuring or estimating the strengths of soils. Slope failures provide a valuable opportunity to estimate the strengths of materials involved in the failure.Stability analyses are performed to back-calculate strengths that could have produced a failure. Back analysis of strengths has advantages over laboratory testing in that the scale is much larger and the materials are in their in situ state.Using site investigations and an appropriate method of analysis it is possible to develope a model of the slope at the time that is failed.In this paper Farahzad landslide have been studied by site investigations and then have been evaluate shear strength parameter from back analysis of failed slope.

The metapelites of North of Golpayegan show that these rocks can be divided into four categories based on mineral assemblages: chloritoid- garnet- biotite- schist, garnet- biotite- muscovite- schist, staurolite bearing garnet- biotite- muscovite schist and Kyanite bearing staurolite- biotite- muscovite- schist. The appearance of chloritoid in chloritoid- garnet- biotite schists shows green schist facies. Garnets in garnet- biotite- muscovite schists shows 3 stage of growth and syn-tectonic formation. The appearance of staurolite in staurolite bearing garnet- biotite- muscovite schists signifies the beginning of amphibolite facies. The absence of zoning in the staurolite contained in these schists suggests the formation and growth of this mineral in a prograde metamorphism. The thermodynamic study of these rocks shows that North of Golpayegan's metapelites were formed within a temperature range of 480 – 560oC and a pressure range of 1.6 – 4.1 kbar. These results are consistent with the mineral's paragenetic evidence and show that effect of metamorphism on North of Golpayegan's pelitic sediments is to lower amphibolite facies (Epidote amphibolite).

The Muteh gold deposit located in the center of Sanandaj-Sirjan Zone (SSZ) in western Iran. Gold mineralization is related to series of quartz and quartz-sulfide veins, lenses and veinlets, cutting the Neoprotrozoic crystalline basement rocks, along a NW-SE trending shear zone. Gold mineralization is closely associated with hydrothermal alteration along the ductile shear zones, with a typical greenschist facies assemblage of quartz+sericite+chlorite+albite, plus sulfidation and silicification alteration zones adjacent to ore body. Ore minerals include; pyrite, chalcopyrite, emplectite (Cu-Bi sulfide), arsenopyrite, pyrrhotite, bismuth, gold and subordinate galena and sphalerite. Native gold occurs in the quartz veins and adjacent to wall rocks as inclusions in the second generation of pyrite and chalcopyrite in form of fracture fillings within rim or around euhedral to subhedral coarse pyrite. Fluid inclusions in quartz veins contain carbonic, aqueous-carbonic and aqueous types in the Chah-Khatoon and Senjedeh gold mines. Homogenization temperature of CO2 (ThCO2) in carbonic inclusion is between 12.6 to 27.3 ̊C. Aqueous-carbonic fluid inclusions show salinities of 2.3 to 12.5 NaCl eq. wt% and total homogenization of 145.6 to 304.2 ̊C. The aqueous fluid inclusions, based on association with auriferous and barren veins categorized as; 1) salinity of 2.1 to 15.2 NaCl eq. wt% and total homogenization of 212.2 to 297.6◦C in auriferous quartz-sulfide veins, and 2) salinity of 16.2 to 28.2 NaCl eq. wt% and total homogenization of 147.4.2 to 245.6◦C in barren quartz veins. While most of aforementioned characteristics of the Muteh deposit are consistent with orogenic (mesothermal) gold deposit, but features such as genetic linkage with tectonic evolution of lithospheric mantle through upper crust with the tectono-magmatic history of SSZ accompanied with extensional structure setting, ore geology style, alteration assemblages, mineral chemistry, vertical elemental zonation and fluid inclusions characteristics presented in this research, it may inferred that gold mineralization in the Muteh deposit can be favored as an reduced intrusion related gold system (IRGS).