JOURNAL OF THE EARTH
Year:2011 | Volume:6 | Issue:19|Papers Count:14

In this paper we study the subsurface down to 1300 m in the east of Alagol lake, located in the north of Golestan province, Iran. Geological structures according to the lithology, porosity and fluids have different responses to electric and magnetic fields. The layers containing salty water have high electric conductivity. The formation is Quaternary geological consists of jammed sediments. According to 1D and 2D models, three conductive layers were distinguished at the depths of 20 m to 90 m, 110 m to 500 m and about 1100 m. The last two layers are interpreted as the layers which consist of salty water. To prove the correctness of the results the 1D model of the MT data are compared with the results of a log record that is located at 4 Km southwestern of station B51.

The observed signal at the seismic stations is under the influence of the recording system. One of the basic reasons is the recording system transfer function or frequency response. Meanwhile knowledge of one of these items is inevitable for the processing and interpretation of the digital seismograms. On the other hand one should never forget that the recorded ground motion is considerably different from the generated signal by seismic sources. Studying the frequency response will help seismologist to separate the path and instrument effects in order to approach the real source signals. So in this paper we have studied frequency response of the Tehran Telemetric seismographic network in displacement, velocity and acceleration domains.

This paper is devoted to application of integrated geophysical seismic methods in the investigation of Seymareh dam site which is located in 40 km NW of Darehshahr city in Ilam Province. In this study,a combination of shallow seismic refraction profiling and seismic tomography methods were applied. The goal of study is to determine the subsurface features and layering geology model for Dam axis. The results lead to identify lead to identify eight layers in the alluvium with maximum wave velocities of 6000m/s,and minimum wave velocities 2900m/s from depth to surface,respectively Maximum thickness of the alluvium was found to be about 40 meter below the dam axis.

In this study, selected statistical methods (Pearson correlation, factor analysis and geostatistics) were used to determine correlation between elements and pollution sources in their spatial variability in different parts of Anzali wetland. During of study Major elements and heavy metals (Al, Fe, K, Mg, Mn, Ti, S, P, Na, Ca, Sr, Ba, As, Bi, Cd, Co, Cr, Cu, Mo, V, Ni, Pb, Zn) concentration in 18 points of wetland and rivers flowing into it were measured. Factor analysis and Pearson correlation results demonstrated that Ni has natural and anthropogenic source whereas As, Bi, Cd, Co, Cr, Cu, Mo, Pb, Zn and V have anthropogenic source. The ordinary kriging method applied for Spatial variability and interpolation of data in geostatistical study. Firstly normality of data was determined by using Kolmogorov - Smirnov test and after semi-variogram calculation, Circular, Spherical, Exponential and Gaussian models were fitted to each of heavy metals. RMS parameter of Cross-Validation was used for model validity. For As, Cu and Pb is exponential and for Cd, Zn, Ni circular are the best models. Results for As, Cu, Ni and Pb reveal the high estimation accuracy. Pollution zonation map that is produced by kriging and GIS showed Hendekhale and Shijan are the most polluting districts and Siakishom is the most none pollution part of Anzali wetland.

Seismic hazard assessment is carried out for the region bounded by 46.50oE-50.50oE and 31.61oN- 35.25o N including Lorestan province. To do this, seismotectonic map of the region has been provided by using geology maps tectonic maps, satellite images, available reports, as well as major and minor earthquakes catalogues in Zagros and Sanandaj- Sirjan region. Eighteen potential seismic sources have been identified by analyzing geological, seismological and geophysical data. Finally, peak ground iso-acceleration maps for return period 475 and 75 have been displayed by probability method PSHA software,in a grid of dots with the distance of 0.25 degree, has been utilized in seismic hazard assessment.Seismic zone map of Lorestan province shows peak horizontal acceleration for 10% probability in 50 years is 0.53g. It is concluded that Lorestan province Can be divided into different zones with relative risk. The most quiet area is located in the north, including Hamedan zone with PGA=0.005g. There are region in centeral with high relative risk include Zagros faults with PGA=0.34g. There is the second hazardous zone, located in northeast, with PGA=0.22g along the Dorud fault.

The studied area is located, in the eastern part of 1:100000 the geological map of Saghez. This region is located in the northern part of Sanandaj-Sirjan zone. In this area some of intrusive masses with the composition of granite, granodiorte, quartz monzonite and quartz diortite which are belongs to upper cretaceous-paleogene, have penetrated to older rocks such as Kahar formation sandstone (Precambrian), cretaceous carbonated and volcanic rocks which caused a weak contact metamorphism on the host rocks and permeable hornfelse by getting in contact with them. These granitoids include the minerals quartz, plagioclases, ortoclase and mafic minerals biotite and horenblende, and are also subsolvus. These masses have mafic microgranular xenoliths, mostly round and oval, with the same petrography and geochemistry properties with mafic margins of permeable mass. Also are accompanied by siliceous veins and aplitic dykes, that their permeation and replacement have been done in a delay phase in comparison with the main mass. Altered diabasic dykes with different magma source from the main mass are exist that has been injected into these granites. Petrography and geochemical evidences indicate the Calc Alkaline nature with medium to high potassium and metalominus to peraluminus of the major magma. Considering to several petrological diagrams, the magmatic fractionation is presumable in original magma by fractional crystallization. Microscopic and geochemical evidences show magma source type I for these granites and various diagrams of different tectonic environments are distinguish indicate of active continental margins for the place granitoids of this area.

This paper presents the application of IP method with respects to polymetal bodies. First, presents the principle of induced polarization method then the most suitable arrays we can use, methods of measuring points, preparing of maps everyday for optimizing exploration plan, the way of writing report include of different maps and for locating the proposed drill holes with compilation of Geophysics, Geology, … results. The most important result of applying this method in polymetal mines exploration is lessening expenses of exploration and denoting the best location for drilling.

The Dalichai Formation in the studied section in Northwest of Ayeneh-Varzan village, with a thickness of 75/5 meters consists mainly of limestone, marlstone and silty marl that based on lithologic changes it has been divided into three informal members. The Dalichai Formation in the studied section overlies the Shemshak Formation disconformable and it has gradually been covered by the thick-bedded limestones of the Lar Formation. In this study totally 60 ammonite's taxa were discovered. Collected taxa belong to the families: Phylloceratidae, Oppeliidae, Morphoceratidae, Reineckeiidae, Macrocephalitidae, Perisphinctidae. Detected ammonites indicate Upper Bajocian to Middle Callovian age. The Study of the Dalichai Formation microfacies and sedimentary environment show that the microfacies of this formation formed mainly in a deep open marine environment. The Dalichai Formation in the studied section, based on index ammonite's taxa has been divided into 6 biozones. The Middle and Upper Jurassic ammonite fauna show closely related to the European and Submediterranean areas.

The studied area is part of East Azarbaijan Province which the important tectonic issue in that area is North Fault of Tabriz. According to the previous investigations the width of this fault is not constant and equal in that area, second the type of fault displacement is dextral strike-slip with reverse movement.Tabriz fault in the category of Alborz Zone, from geological point of view is located in Mako-Tabriz subzone. By investigation at satellite images from the region and following the canal (water print) way can be found that the fault is dextral strike-slip.As an example the satellite images from Khaje Marjan region and Gouri Gol, canals (water prints) shows dextral displacement in its own way of movement.The trend of Tabriz north fault is 65 degree west and the dip is 90 degree.According to the facts it seems that the activity of this fault starts from Devonian period, however it is possible that the age of it becomes older.In this paper it is tried by using Image processing techniques contrast enhancement increases and make the image more useful for processing.The processing techniques which are used in this paper: contrast enhancement, composition of colors (RGB), filtering, principle component analysis, using the DEM images, Band Ratio.Finally in this paper the ETM+ data was used from landsat 7 satellite.

Analytical results of samples that collected from Babanazar area approved many of points as highly concentration of heavy elements such as, As, Zn and V. The grades of concentration of above toxic elements are mostly Higher than contamination rates.Therefore the study area divided to there part:Babanazar area with As, V, Cr pollutionCheshmeh Kazem area with Zn, V, Cr pollutionGheshlagloo area with As, V pollutionThe grades of elements background of rock units of the study area are very high, therefore The sources of polluted zone could be Related to this units (Geogenic Pollution).change of phisico-chemical Condition and Self Pollution, Caused the Concenteration of Heavy Element in this area.

In order to estimate the seismicity of the Shahriar province, located in south west of Tehran city, at first geological and seismotectonic particulars were studied, and seismic sources in the province and suburb of this region, with 50 km radius range were recognized. With usage recorded microearthquakes in region, seismicity map of province, and seismicity parameters of area obtained, In view of this fact that Shahriar has been situated in “very high macrozone hazard” at the once glance, sustaining an injury of schools in the center unit of education and training of Shahriar studied, in outlook of earthquake and was resulted that 73 precent of schools buildings of region have not any side resistant system and need to make resistance or rebuilding. In case study we considered the building of8 schools of this area particularly. In purpose of decreasing casualties and damages, are suggested: to organize active crisis management staffs, for determining the student groups duties, and increasing the level of knowledge and skills of students in facing of earthquake.

Carbon has two very different crystal form: the hardest known natural material, diamond, and one of the softest, graphite. Originally, diamonds were found among river and beach gravels, but now they are mined from the volcanic igneous rock kimberlite, in South Africa, Siberia and Australia. Although very hard, diamond is brittle and easily cleavable - which allows gemcutters to get the best from the stunning play of light that it offers.