JOURNAL OF GEOTECHNICAL GEOLOGY (APPLIED GEOLOGY)
Year:2010 | Volume:5 | Issue:4

The Upper Cretaceous Gurpi and Lower Tertiary Pabdeh formations as units of Folded Zagros were studied in three different regions (Tang-e-Abolhayat, Tang-e-Zanjiran and Maharloo) in Fars Province. Gurpi Formation consists of thin to medium bedded gray marl and marlstone interbedded with thin layers of argillaceous limestone and shale. The dominant Microfacies in this Formation are biomicrite; Index species of Globotruncana give the age of the Formation from Lower Campanian to Upper Maastrichtian. Pabdeh Formation consists of bluish gray, thin to medium bedded shale and marl and interlayers of argillaceous limestones (with purple shales and thin cherty beds) at lower part, dark gray shales and marls with interlayers of argillaceous limestone in the middle, and alternative layers of thinly bedded argillaceous limestone, shale and marl at the upper part. The dominant Microfacies are biomicrite. Index species of Globorotalia and Hantkenina give the age of Formation from Upper Paleocene to Eocene. The sedimentary environment of both formations is a bathymetrical carbonate floored basin (deep shelf or basin margin) which has deposited its facies in transgressive stage. The contact between the two formations is disconform. In Tang-e-Abolhayat it lies at the base of purple shale. In this region and also in Tang-e-Zanjiran and Maharloo, in addition to the recognition of Globorotalia velascoensis, which is attributed to lower part of the Pabdeh Formation, a glauconitic-Phosphatic bed separates the two formations. This bed represents a non-depositional (epirogeny) period from the Late Maastrichtian to the end of Early Paleocene.

Binaloud basin is located in the center of Khorasan-e Razavi province, namely between Binaloud to the north and Central Iran geological zones to the south. It is influenced by tectonical and erosional factors. The controlling major and minor faults trend mainly NW- SE.  Due to rock type and tectonic activity, the studied area is a plain.  The existence of ophiolite units caused that the main rivers are of subsequent type. Also due to lithological properties, the most drainage patterns are of dendritic type.  Binaloud basin includes two large subbasins, namely Baz-e-Hour and Kal-e-Siah, each one consisting of various geomorphological phenomena. Those phenomena that have been identified in Baz-e-Hour and its subbasins (Qareh-Cheh) are landslide, badland, talus, rills and gullies. The last two features are responsible for transporting the most sediment into the basins, whereas in Kal-e-Siah basin, mass movement and slumping are the main sediments. The geomorphic studies could help detailed identification of the sediment supply areas, and their transportation ways.

The Soltan-Meydan basaltic suite (SMBS) contains a range of mafic volcanic rocks such as: basalt, trachybasalt, basaltic trachyandesite and basaltic andesite with a thickness of 1069 m.  High SiO2 and rhyolitic volcanic rocks in this suite may indicate bimodal volcanism. In addition, this suite includes xenolite of alkali feldspar granite at its agglomerate level, which indicates contamination of primary magma of SMBS by continental crust. This contamination becomes evident by samples with high K2O and high alkalinity. SMBS magmatism exhibits transitional character so that the samples plot near the discrimination line of alkaline and sub alkaline series, but they have a tendency to alkaline series.

Khatounabad plain is located in the southeastern part of Iran. According to the weathering situation of the studied area, there isn't any permanent river there and like other places of Kerman province this area is dependent on groundwater. With a view to  the  existence of Khatounabad copper smelt factory  and also molybdenum factory on this plain and the importance of Khatounabad aquifer in providing water for industrial, agricultural, and drinking needs of the area, the vulnerability of Khatounabad  groundwater to pollution is studied in this paper, by using drastic model. GIS is used for the preparation of the Khatounabad groundwater vulnerability map. This research shows that 8.54 percent of the studied area is located in high vulnerability situation, 63.55 percent in moderate vulnerability situation and 27.91 percent in low vulnerability situation. High vulnerability situation is located in the upstream part of the plain, so pollution could be distributed in the whole area form this part. Since factories of the area (Khatounabad copper smelt factory and also molybdenum factory) are located in the high vulnerability part of the plain, monitoring of soil and groundwater  is important. According to sensitivity analysis, maximum sensitivity is related to unsaturated layer and minimum sensitivity is related to soil composition.

Analysis of digital satellite data around Gowk fault in Kerman province indicates active tectonics of this region, Also, field observations in this area showed that the morphology of valleys has been affected by the action of Gowk fault. Moreover, the activity of Gowk fault could be confirmed by seismic data and recent strong earthquakes, but in this study morphometric indices which cover more periods than seismic data are evaluated by using the ratio of valley floor width to valley height (Vf) morphometric index. Landsat digital data and topographic map of the area are studied by Arc Map software. (Vf) stations also are controlled by conducting some field work. Results indicate that Gowk fault could be introduced as an active fault based on (Vf) index, and in its northern part it is more active than in the southern part.

Kupal oil field is located at 50 km NE of Ahwaz and following follows the Zagros trend. Every unpermeable rock or bed that covers the reservoir is called cap-rock. Member 1 of the Gachsaran Formation as cap-rock of the Asmari reservoir, it has 6 key beds namely, A, B, C, D, E, F (top to base) that alternate with anhydrite and marl. GR well logs with stratigraphical column are designed by logplot 2003, applied for petrophysical evaluation of cap-rock. To get more information, the cut selected samples were run through SEM (Leo1455vp). The results of changed GR well logs of selected wells, thin sections petrography and SEM  analysis, show that key beds lithologicaly are formed from A(anhydrite), B (bitumineous shale) and C, D, E, F (limestone). In a few wells, some clay was added to limestone and caused the API degree to increase. Spectrographic studies of sulphates between key beds show that anhydritization, cementation, compaction, recrystalization and replacing are the common diagenetic processes in cap-rock occurrence. Anhydrite is found more than the other rocks in the cap-rock. From NW to SE of the field, the cap-rock thickness is reduced.

Permeability, rock type and core facies are the most important parameters of the reservoirs. It has been attempted in this study that above parameters are predicted indirectly from electrical logs by using fuzzy logic and fuzzy possibility method. Then the obtained results are compared with the core data. For this purpose, core data and logs of two wells in Coastal Fars gas field are used. This soft computing concept of fuzzy logic has been around since the 1960’s, but has only recently been applied to reservoir characterization and in use modeling. This is mainly due to the dramatic improvement in the speed of computers. The results reveal a very good match between the measured core data analyses and the fuzzy logic determination of permeability, rock types and core facies.

Identifying, controlling and preventing human and socio-economic damages caused by natural disasters such as landslides are considered as one of the main goals of research institutes and executives. The purpose of this research is to identify landslide hazardous and secure zones and zoning these according to the risk and modeling landslides within fuzzy inference network through fuzzy logic operators using RS & GIS techniques in Lajim watershed, in Central Alborz, Mazandaran. The parameters applied in zoning landslide hazardous zones are: geology, soil, elevation, slope, slope direction, the distance from rivers, roads and faults, vegetation cover and land use. In order to prepare the fuzzy membership function, the weight of effective factors was calculated. The results show that land use has the highest weight; therefore it is the most effective parameter. Among different models applied in this project, the fuzzy Gamma 0.7 and the OWA (Ordered Weight Average) model have the least variability in the modeling process. Also, these two models have the least SD (Standard Deviation) compared with the other models. Hence, they are our final models for mapping landslide hazard zones.