Researches in Earth Sciences
Year:2011 | Volume:2 | Issue:7|Papers Count:7

Rivers are one of the most important dynamic ecosystems and knowledge about their changes trends and foreseeing their future quality make it possible to predict their probable future issues and to perform planning for the rivers. Minab basin has been formed from two main branches of Rudan and Jaghin rivers that are connected together around Bemetin. In this study, in order to investigate the qualities variations of water, topographical state of the basin was determined by topographical and land use maps; and anthropological and natural factors affecting water quality and quantity were identified by field and library investigations; and water samples were collected from different areas of river and then were analyzed. Statistical parameters that are important for qualities indices were calculated to study the quality variations; and edible water of the river was classified by Piper and Stiff diagram method; and was classified irrigation water and agriculture uses of water by Wilcox diagram method. Electrical conductivity of surface waters had good correlation with TDS, chloride, sodium and magnesium ions but there was not good correlation between electrical conductivity and bicarbonate ion. The selected samples are placed in the J section of water groups according to Wilcox diagram. Chloride and sulfate were the highest and lowest ions in the most samples according to Stiff diagram, respectively. The highest density of samples is placed in saline area in different years according to Piper diagram. The results of the present study showed that expansion of farmlands to the edge of Jaghin river, encroachment along river frontage, application of pesticides and herbicides, exploitation of high amount of river's water for agricultural use, high density cultivation, lack of proper agronomic management are able to decrease the discharge of water and increase the concentration of pollutants downstream.

Every year, thousands of kilometers of forest roads will be constructed by which millions of acres of vegetation and trees are destroyed and millions of cubic meters of soil moved. This research to investigate the effects of some topographic elements and road age on area erosion of edges forest roads to 150 meters distance in education- research Forest of Tarbiat Modares University. Initially, maps of slope, aspect and elevation were obtained. Then, the erosion forms of the region around the road were surveying 'Using GPS. The results of the survey showed that the maximum side effect of road on the erosion is 48 meters away from the edge of the road. So the results of the one way analysis variance showed that, between erosion area phenomenon with different classes' slopes, elevation and age roads have existence significant on the level 5 percent level and with the aspect have existence significant on the 1 percent level. So that 15-30 percent slopes, north-west aspect, altitude of 600-800 meters and 3 years of age class have the most area of erosion. The results of regression model showed that the slope provided the most important factor affecting the increase levels of erosion and the then of slope area, age road is the most important factor influencing the extent of degradation of forest roads in the study area.

This paper firstly defined APS sector with emphasis on Tehran's trans-national function and secondly examines the location determinants and characteristics of the accountancy and auditing firms (AAFs) in Tehran. Analyses of data collected from 40 firms of almost 200, including questionnaires, interviews and published documents reveal that firstly a new sector of corporate services-based sector has been shaped in recent years and extended to the north of Tehran and suburbs with a high environmental quality. Secondly we found that, AAFs in Tehran lacks international functions and they have a weak relation to the global cities network. Finally, the paper concludes that, although Tehran has high capacity international relations and participating in the global cities network, Tehran isn't a world city yet; its accountancy and auditing sector is a good example of this situation.

In order to investigate the land capability for the best use and resource conservation of Famenein region, firstly, topographical layers, plant cover and petrological and soil properties of the area were provided in GIS and were modified with field studies. Then, land types and units were classified according to standards and instructions of institute of water and soil studies. These studies led to determination of 10 homogeneous work units. Land capabilities for these homogeneous units were determined via profile digging and sampling of existing soils of the area and analysis of these data in framework of Iranian land evaluation model. Revision of the outcomes, which was done with the aim of best use and management and in order of sustainable development, resulted that only 36% of the region lands are appropriate for fanning, 40% of the region lands are appropriate for dry farming and 60% have a good potential for pasturing. Comparing the current usages of the region with these results, it is observed that there is about 10% of the region complete conformity between current usage and land capability. This indicates that most lands in Famenein are used more than their capabilities, which in long times, this leads to loss of the resources.

Three species of Trigoniidae and Megatrigoniidae bivalves, from Trigoniida order belonging to three subgenus Linotrigonia (Oistotrigonia); Pterotrigonia (Pterotrigonia) and Pterotrigonia (Notoscabrotrigonia), have been identified from the Kazhdumi Formation at the Anneh and Mish anticlines in the Zagros basin, southwest of Iran. Trigoniida was considered as the principal cosmopolitan element during the Cretaceous (Berriasian-Maastrichtian) time and the different order of them were well distributed in the relatively low temperature gradients between polar and equatorial regions. Many of them lived marginally infaunal, in shallow nearshore, high-energy environments and they were suspension feeder.

Analysis of benthic foraminifera within the Asmari and Razak formations lead to recognition of 18 genera and 24 species. Based on this study, 2 biozones (Nummulites vascus-Nummulites fichteli and Archaias asmaricus-Archaias kirkukensis- Miogypsinoides complanatus) idenetified for the Asmari and 1 biozone (Bore/is melo curdica-Borelis melo melo) for the Razak Formations respectively. Regarding to these assemblages, the Asmari Formation is Rupelian to Chattian and the Razak Formation is Burdigalian in age. Association of carbonate grains of the Asmari and Razak formations in the study section are classified as foramol and foralgal-foramol facies, considering the presence of large benthic foraminifera accompanied with bivalve, bryozoan, echinoderm, patch of coral, gastropod and in less amounts of red algae and green algae. Presence of green algae, corals, bryozoans and bivalves fragments indicative of a transition from heterozoan to photozoan association called the heterozoan + assemblage.

In this article, the type of the shear in the Zendan (Minab) fault zone, located at the Northeastern province of Hormozgan, western territory of the village of Faryab in the vicinity Roudan- has been analyzed and evaluated. The Zendan fault zone, considered one of the most prominent and famous fault zones in Iran, has been interpreted to be of a dextral pressure mechanism. However, the recent researches carried out in this zone, in addition to dextral movement component, indicate sinistral movement component, as well. The evidence proving this conclusions include: fault planes and slickenside, chocolate boudins, domino boudins, C-S fabric, and the microscopic studies on the mylonites of the correlated zone. The existence of the chocolate boudins is a proof on the change in the direction of the extension in the studied region during the passage of time. The existence of the chocolate boudins is a proof on the change in the direction of the extension in the studied region during the passage of time. In addition, direction nomination paleo- stress with stress inversion method, with specific software for the - fault planes, which have been categorized in two types of faults -those of the dextral movement component and the ones with the sinistral movement-, also indicate this change in the direction in the stress vectors. In terms of right-lateral shear, strike of maximum stress (s1) is NE-SW and left-lateral shear, indicate that strike of maximum stress (s1) is WNW-ESE. according to this statments that the microscopic studies on the mylonites of the afor -mentioned zone, which are so much older that the young streams that indicate right lateral strike slip off set, prove the occurance of a left lateral strike slip movement, one could perhaps claim that the left lateral sterike slip movement might have existed before the right lateral strike slip movement that exist at the present time.