Iranian Journal of Geology
Year:2006 | Volume:2 | Issue:5|Papers Count:9

Biseriammininae subfamily includes genera that have great species diversity in Upper Permian sediments. This subfamily has a great distribution in Upper Permian sediments in most parts of Iran, especially Zagros Mountains. Based on identification of species and index species, the biozones have been presented that can be used for biostratigraphic study of the Permian sediments in the region Furthermore, according to the similarities and differences between genera and species of each genus phylogenic relationship can be demonstrated. The Oshtoran-kuh region has been selected of this study, be ….. the complete section of Upper Permian sediments is exposed in the Zagros basin. Sections of the different genera have been drawn by camera lucida instrument and species have been differentiated based on the structural properties of the shell. Finally 24 species of Globivalvulina genus, 8 species of Paraglobivalvulina genus and 1 species of Paraglobiva-lvulinoides genus have been identified and the evolutionary pattern of these genera and their species are presented.

Rudbar Lorestan Dam and Power Plant locates on the High Zagros structural zone, according to the geological map of Iran. The Dalan Formation, Permian age, forms the geological structure of dam body foundation and a portion of its reservoir. Meanwhile, outcrops of an Upper Cretaceous formation, called Sarvak Formation, are exposed out beside the Dalan Formation, due to effect of thrust faults. The main sources of Rudbar Lorestan river are precipitation and drainage of groundwater. The karstification process in carbonate sediments at the site was expected to be expanded well, due to geological and climate conditions. However, based on the evidences of karstic features, which could make a drainage network, have not seen. Both confined and unconfined aquifers present in the site. In this regard, presence of artesian boreholes is a good evidence for confined aquifer. The dominant types of ground water are calcic bicarbonate and sulfate, based on chemical analysis of 22 samples, collected from six sources of water at the site, In this manner, the types of water of the Rudbar river, Kish spring and outlet of access tunnel T2 are calcic bicarbonate, because of recharge from unconfined aquifers and short residence time. However, the type of water of artesian boreholes, i.e. TG-4 and RB-8, and inlet of the access tunnel T2, are calcic sulfate, based on contact of water with sulfate minerals and long residence time in confined aquifers.

The Soltanieh Formation “Southeast Zanjan” consists mainly of carbonate and shale sequences. Geochemical studies such as sr/Ca and d18 values of shows that these carbonates were affected mostly by open system meteoric digenesis. Distribution of major and minor elements such as Sr/Na and Mn versus Na and d18 O and d13 C values of limestones in Soltanieh Formation indicates that the mineralogy of carbonate were originally aragonite. These data fall within the Mozduran limestone and Gordon limestone (Tasmania, Australia) fields due to similar aragonite mineralogy. Original aragonite mineralogy for Neoproterozoic limestones from other parts of the world has also been suggested and can support our interpretation. Light d13 (-4.57 0/00  VPDB) values in Soltanieh limestone support meteoric diagenesis and Sr/Mn variation indicates high dissolution rate of limestone.Pale temperature calculations, d18 O values (-5.83 0/00 VPDB) and dw 3±1 , range between 23% - 31%c, respectively.

Parsi oil field is located in the north central part of Dezful Embayment. On the basis of subsurface data and applied suitable methods for subsurface analysis, the mechanisms of folding and fracturing in this structure have been presented.Since the forelimb of the anticline is affected by a thrust fault, it is suggested that the Parsi Anticline is a fault related fold, and because of it’s significant characteristics, the anticline is of detachment fold mechanism with hinge migration and limb rotation model.Methods of Geometrical analysis, drilling data and core studies are shown that reservoire’s zones of 1 and 2 of the Asmari Formation are of highly fractured zone. Also SW limb of SE culmination and NE limb of NW culmination are recognized as part of this structure with prominent fractures.

Lateshur watershed is located in northeast of Pakdasht in the Tehran Province and has surface area more than 22.2 km2. Hezardareh Formation, Neogen red beds and Quaternary alluvium crop out in this watershed. A dam has been built at the downstream part of this watershed that half of this reservoir dam filled with sediments during 12 years period. This subject caused lots of problems for the villages and agricultural lands in the downstream of watershed. This indicates that the rock units exposed in the upstream can produced a huge amount of sediments. We calculated the rates of sediment yield deposited in the reservoir of Lateshur dam with topographical maps during the period of 1993-2005. We used clay minerals as a tracer and multi linear variation methods for calculating of sediment yield from rock units. Based of clustering and F test, montmoriolite and illite are determined to be tracers. Finally, we conclude that marly member of Neogen red beds are the most sensitive rock unit to erosion and produced more than 97% of sediments yield that have been deposited in Lateshur dam reservoir.

In order to assess the separability of different soil types, three different data sets, including Visible and Near-infrared (VNIR), Shortwave Infrared (SWIR) and thermal bands with the spatial resolution of 15, 30 and 90 m of ASTER data respectively, were selected. In this study, the geometric and atmospheric corrections were applied for all images. Combination of seven different band were analyzed in order to characteristize the soil types. The train samples were chosen upon directing homogenous units on the  color composite, using field study and other information. The images were classified by using maximum likelihood algorithm, and then the results were compared with the ground truth map and information. Mean, standard deviation and variance of sample sets were analyzed. The results showed that the saline and gypsiferous soils have high spectral reflectance in visible and short wave infrared bands, while the spectral reflectance of moist saline soils with polygon crusts was the lowest. This means, puffy crust and soil moisture reduce the spectral reflectance. The results of supervised classification with combination of DEM map and remote sensing data have shown an overall accuracy of 79.66 and kappa coefficient of 0.781. Based on the results obtained from this study, we may generally conclude that ASTER data can be useful for differentiation of some soil types.

Dehno (Mashhad) is an area of metamorphic and granitic intrusions. In some layers of rocks in schists, staurolite is present while chloritoid is absent. Study of fabric elements show that chloritoid and staurolite formed during the same deformation phase (S2) with similar pressure and temperature conditions. Chemical analyses of these rocks and investigation on geochemical diagrams show that the rocks chemically similar; suggesting that replacement of chloritoid with staurolite in sequence of layers might be controlled by metamorphic fluids. Low oxygen fugacity (low XCO2) condition in some layers which can be confirmed by the presence of graphite in the rocks; increases the stability of chloritoid and prevents the formation of staurolite. Staurolite formed during the pick metamorphism in the area; suggests that in the highest metamorphic condition, CO2 bearing fluids played significant role on metamorphic reactions and formation of different metamorphic assemblages. However, fluid flow was limited to individual layers and different fluids were not able to move to mix and make a homogeneouse fluid in the area.