GEOCHEMISTRY
Year:2013 | Volume:1 | Issue:3|Papers Count:7

The aim of this investigation is to evaluate the quality of springs in the Masjed Soleiman area, that are main sources of drinking and agricultural water in this area. Spatial variation of water quality of springs is visible in different sectors and many factors are affecting the quality. In this study, in order to evaluate the groundwater chemical quality, hydro geochemical methods were used i.e. ionic ratios and composition diagrams. Water quality was determined for irrigation by using Wilcox and Schoeller diagrams and the water samples are generally located in suitable water class. The water type in most samples is (Mg, Na, Ca)-SO4 and some of them are Na-Cl and (Na, Ca)-HCO3 type. According to the results of correlation coefficients between different chemical parameters and geological analysis, the lithology of formations comprising the aquifer is the main factor affecting the water quality, which causes the extreme decrease of water quality. In this study, ionic ratios of (Na+K-Cl)/(Na+K-Cl+Ca), Na/(Na+Cl), Mg/(Ca+Mg), Ca/(Ca+SO4), Cl/ (sum of anions) and HCO3/(sum of anions) and composition diagrams were used for characterizing groundwater influencing factors. Based on the results, processes such as dissolution of gypsum and halite, sodium sulfates, Na-rich plagioclase weathering and ion exchange affect the spring quality in Masjed Soleiman area. The results of calculation of saturation index show that the saturation index for calcite mineral is positive and for gypsum, anhydrite and halite minerals is negative.

One of the features of arid and semi-arid is salinity of lands and water resources being used for irrigation. Therefore, accurate measurement of the concentration of ions in groundwater and surface water are among the initial steps for assessment of the quality of water for various uses including agriculture. In order to assess the geochemical irrigation water of Zirrah plain, 19 groundwater samples and 5 surface samples were taken and also the ratio of ESP, RSC, Ca / Mg, PI indices and Wilcox's classification were used. Piper diagram of water samples showed the dissolution of halite mineral. According to the salinity of Zirrah plain irrigation water, plants adaptation to these sources of salinity was determined after geochemical evaluation of irrigation water. The results show that the salinity of water resources except Shahpour River is more than allowable values. Shahpour River has the best quality among water resources of area.

The study area is located in the south east Zarand in the structural- sedimentary zoning, this area belongs to Centeral Iran parts. Organic geochemistry investigation for determination of organic matter quantity, quality and thermal maturity were carried out on sediments of the upper portion of the Hojedk (Middle Bajocian- Lower Bathonian) from sites in near Hojedk Village, Hojedk Formation with more than 1000m, thickness and the major lithology of sillisic terrigenous rocks, shaly and coal layers has many outcrops in the area North of Kerman. The result of Rock-Eval Pyrolysis on the samples at the upper portion of the Hojedk Formation shows that with pay attention to content and maturation of organic matters can be source rocks of this zone. In these study 14 surface samples from shales and coal layers was estimated. The Total Organic Carbon (TOC) content of sample is between 0.04 and 46.82 wt% and indicating a poor (shaly samples) to excellent (coaly samples) organic matter content. Analys Rock-Eval Pyrolysis reveals the dominance of organic matter with terrestrial and rarely marine origin. Tmax values obtained for kerogen from Rock-Eval pyrolysis ranges from 441oC to 559oC with average 468oC, indicating mature and over mature organic matter and therefore with a view to thermal maturity is at the end of oil window zone and beginning of condensate, wet gas and dry gas generation zone. The location of studies samples on the van-krevelen diagram (HI Vs OI) shows of mixture of kerogen type III and IV, This diagram shows that the upper portion of the Hojedk Formation has the hydrocarbon potential of gaseous. Based geochemical parameter, the upper portion of the Hojedk was deposited in a meandering river environment.

In this study, one limestone and one dust sample and 17 topsoil samples were collected in the vicinity of the Karoon cement factory and were analyzed by ICP-OES for their heavy metal content such as Cd, Pb, Cu, Zn, Ni, Cr and Co. The abundance of measured heavy metals in the soils was decreased as: Cr> Zn>Ni>Pb>Cu>Co>Cd. Based on the results, the source of these metals in the soil samples are linked to the dusts enriched in heavy metals derived from cement production. According to the comparison bet-ween results and available standards and criteria such as enrichment factor, pollution index and geoacc-umulation index, it has been concluded that Karoon cement factory has not caused any major contamin-ation of heavy metal to its nearby.

dakhavid feldspar deposit soil is located at 70 km southwest of Yazd city. From the geological point of view, the area is a part of Central Iranian zone located in Urumieh-Dokhtar volcanic belt. The deposit is formed as Quaternary alluvial sands in the fault contact zone of Shir-Kuh granite with Jamal Formation carbonates (Permian). This fault zone in now active and there are emanations of sulfur-bearing gases (fumarole) in parts of area. The succession of arens and loosely-consolidated sandstones are predominate lithology in the mining quarry. According to petrographic studies on unconsolidated sediments, the granitic composition of grains is determined. These sediments could be considered as litharenite and arkose according to the Folk classification. The following main mineral composition deduced from XRD analysis: Quartz + albite + muscovite + illite + orthoclase + jarosite + Poor sorting and roundness of grain components indicate that the host rocks of these terrigenous clastic sediments are near the deposit. According to field evidence, petrographic and comparative mineralogical studies of samples with Shirkuh granite, it is obvious that batholith has an important role as the source materials for Bidakhavid deposit. The sediments are of economic value and are known as industrial soil in mining literature. The deposit is formed in the subduction zone tectonic setting. REE normalized pattern in all samples is indicative of the intense enrichment of LREE and depletion of HREE. This pattern shows that Shir-kuh granitic rocks are the source of Bid-akhavid sediments.d18 O and dD values of the Bid-akhavid sediments range (-3.34‰ to -7.6‰) and (-48.34‰ to -75.4 ‰) respectively. These data indicate that connate water played essential role in the alteration of intrusive protolith and formation of the sediments.

The basaltic rocks are located in the northeast of darrod city-Neyshabour, northeast Iran between longitudes of 59o 8' to 59o 16' E and latitudes of 36o 7' to 36o 11' N. The age of these rocks is Silurian and they have various petrographic composition including normal basalt, olivine-basalt, trachybasalt, basaltic andesite, basaltic trachyandesite, and dolerite. On the basis of the trace elements geochemistry, the rocks are alkali basalts. The geological map of Torghabeh reports these rocks as pillow lavas, however, the study area is tectonized and these rocks are fragmented, hence pillow structures were not found in this area. The different diagrams show that the rocks were produced from an alkaline magma. Spider diagrams of incompatible elements such as LILE (Ba, Rb, K, Th) show an intense impression of alteration process, and enrichment of HFSE (Nb, Ti, Ta) shows enriched mantle source (asthenosphere) for these rocks. Also Pb positive anomaly in spider diagrams shows crustal contamination in petrogenesis of these rocks. Tectonic setting for the basaltic rocks is a within-plate setting. Since coral fossils in the carbonate-sandstone facies of the area belong to Devonian, it can be concluded that volcanic rocks erupted at a shallow water environment during Caledonian phase.

Kolah Ghazi granitoid body located in Sanandaj-Sirjan zone is composed of quartz, plagioclase, K-felds-par, biotite and accessory minerals such as tourmaline, cordierite, andalusite, sillimanite, kyanite, spinel and garnet. Based on microprobe analyses, cordierites of the study area are of high temperature and low pressure metamorphic type formed in expense of biotite during antexis of pelitic rocks. The spinels are hercynite in composition and derived from metamorphic of enriched-Fe sediments. The formation of symplectic intergrowth texture of spinel in the rims of andalusite and cordierite may be related to the reaction between andalusite and the adjacent biotites. This may be an indication of imbalance condition caused by pressure reduction from tectonic movements. The inherited A/CNK from host pelitic rocks is responsible for crystallization of andalusite.