Kharazmi Journal of Earth Sciences

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The various species of Alveolina for biostratigraphy of Eocene sedimentary rocks are very important. In this research, the species of Alveolina  are reported for the first time in three cross sections: Chalonak, Kalaterood and East Beinabad. These sections are attributes to Early- Middle Eocene age. The 55 samples collected from Chalonak section and the thickness is reached to 245 m. In this section, four biozones are distinguished. They are following: Alveolina globula-Alveolina solida interval range zone, Alveolina solida-A .globosa interval range zone, Alveolina globusa total range  zone and  Alveolina aragonesis  total range zone. On the basis of index fossils such as  Alveolinana  avellana, A. aragonensis,A. globula, A. leupoldi, A. globusa, A. elliptica nutalli, A. rotundata, A. corbarica, A.solida, which are existing in these biozones, the age of this section is attributed to Early Eocene. Of course two species of Nummulites (Nummulites globulus, N. atacicus) and Cuvilierina valensis are determined in Chalonak section. The 80 samples are collected from Kalaterood section and the thickness is reached to 242 m. In this section, four biozones are distinguished. They are following: Alveolina solida- A. globosa interval range zone, Alveolina globosa total range zone, Alveolina aragonensis-A. canavarii interval range zone and A. canavarii total range zone. The several index fossils are found in this section following: Alveolina aragonensis, A. decipiens, A. Avellana, A. laxa, A. pasticillata, A. canavari, A . globosa and A. solida. The age of this section is Early Eocene.  The 150 samples are collected from East Binabad section and the thickness is reached to 900 m. In this section, four biozones are presented. They are Glomalveolina   lepidula – Alveolina solida interval rage zone. Alveolina elliptica nutali- Alveolina corbarica interval range zone, Alveolina corbarica total range zone and Alveolina ruetimeyeri-Alveolina levantina assemblage zone. There are several index fossils such as Alveolina corbarica, A. elliptica nuttalli, A.levantina,  A. roetimeyeri  and  A. decipiens, Glomalveolina lepidula. The age of this section is early Eocene.

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This paper focuses on the application of Geoinformatic methods (simultaneous using of remote sensing, geographic information system, global positioning system, terrestrial and aerial photogrammetry) in optimal operation and exploration risk reduction of oil and gas reservoirs. To approach the purpose, two aspects of remote sensing (satellite image) and terrestrial and aerial photogrammetry have been investigated. The main role of satellite images is usually structural identification and alteration detection using geometric and radiometric analyses. Lithology investigations of the area are studied together with hydrothermal alteration of rocks, hydrocarbon index and geobotany model. Photogrammetric analyses are performed with the goal of qualitative interpretation of the scene and creating 3D models for the desired area. In the present research, the Saracheh area in Qom province, which is according to geological evidence and exposed hydrothermal alteration zones, has been studied. To achieve this goal, image processing of ASTER multi-spectral imagery of Terra satellite was utilized. Moreover, classification methods by means of SAM and SID algorithms for detecting mineral alteration zones and lithological grouping have been carried out. Finally, extracted information layers of terrestrial, aerial and spatial data were combined together to validate the results with independent data. The desired oil and gas potential map is produced according to multi-criteria decision making (MCDM) procedure. Field surveys and interpretation of photogrammetric photos and other evidences indicate that the potential mapping of the hydrocarbon resources is accurate and the results are consistent with the field observations at a high level of reliability (more than 75 percent accuracy).
 

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The Alvand complex (Hamedan province) comprises several bodies ranging from acidic to intermediate and basic compositions intruded in the regional metamorphic sequence of the area (the Hamedan phyllites) during various magmatic episodes in Jurassic. In northern part of the complex (the Cheshmeh-Ghasaban area) there are some outcrops of hornblende gabbro and olivine gabbronorite. The olivine-gabbronorites are composed of olivine, clino- and ortho-pyroxene, plagioclase and hornblende. Apatite, magnetite, titano-magnetite, pyrite and chalcopyrite are the accessory minerals. The alterations include substitution of the olivine and pyroxene by bolingite, serpentine and chlorite. Electron microprobe analyses show that the amphiboles are of pargasite, and magnesio-hornblende. Variations of MgO, Al₂O₃ and Na₂O and thermobarometry calculations based on amphibole and plagioclase compositions indicate that pargasites formed in average pressure and temperature of 11 kbar and 835°C, from metasomatized mantle derived melt as a result of asthenospheric mantle elevation and in extensional setting. Mafic magma contaminated with crustal material as it ascends. This situation can be provided in a rift setting (probably a back arc basin). Investigation of Fe and Ti concentration variations in the plagioclases indicates that differentiation trend of the parental magma was not consistent with concentration of these elements in the melt. High fO₂ and slow cooling rate of the magma caused Fe-depletion during plagioclase crystallization. In addition, formation from a Fe-depleted source could be another factor that limited iron mineralization of the Cheshmeh-Ghasaban olivine-gabbronorite.