GEOCHEMISTRY
Year:2016 | Volume:5 | Issue:1|Papers Count:7

The Chahargonbad granitoid batholith is located in northeast of Sirjan in southeastern part of Urumia- Dokhtar Magmatic Zone. This batholith is acidic to rarely intermediate in composition and intruded into Eocene volcanic rocks. Though the main volume of batholith consists of granodiorite and monzogranitic rocks, it is also composed of quartzdiorite, tonalite and syenogranite. The contacts are gradational. They have granular with subordinate porp- hyritic texture. The enclaves occur as xenoliths, microgranular mafic rocks (diorite to quartzdiorite in composition) and autoliths (tonalite, granodiorite and monzogranite in composition). The Chahargonbad intrusive rocks are also cut by different types of dikes which are mainly consist of dikes and veins of pegmatitic stage, microgranular dikes (andesite and basaltic andesite in composition) and mafic microgranular dikes that are petrographically similar to mafic enclaves. The geochemical evidence shows that the Chahargonbad granitoid batholith is I-type with magn- esium nature which is typical of the Cordilleran granitoids. Based on the tectono-magmatic discrimination diagrams, all samples from the Chahargonbad granitoid batholith show characteristics of arc-related environments formed in an active continental margin.

This paper investigates the groundwater pollution and drinkability of water for human and livestock in Anar plain. In this regard, 32 water samples were taken from pumping wells across the plain and concentration of heavy metals, including arsenic and selenium, were measured in 21 samples and major ions were measured in all 32 samples. Concentration maps of these elements were produced using GIS techniques. According to Boolean logic and overlaying the maps, drinking quality of groundwater for human and livestock was determined. The results demonstrate that permissible drinking water resources for human are located in a small area of the plain in west Mohanmmad Abad and near Ali Abad Sadat villages. However, the area with drinkable water for livestock is larger because of quality standard differences and it is located in eastern area of the plain. The resulting maps can be used to determine location of drilling well sites in order to extract drinking water for household consumptions of villages as well as animal husbandries in this area and their use is recommended.

In the recent decades, concentration of heavy metals in soil attracted considerable attention because they are non-degradable in comparison with organic pollutants or radionuclides. The aims of the study were determine extent and distribution of heavy metals based on the distribution maps and correlation of metals in north Torbat-e Jam soils. Contaminant Factor (CF), Enrichment Factors (EF), Geoaccumulation Index (Igeo), modified degree of Contam- ination (mCd) and Pollution Load Index (PLI) were used to evaluate the soil pollution in the samples. The data reveal that soils in the area are contaminated, showing higher levels of Antimony, Cobalt and Boron elements than normal distribution. Geoaccumulation index classified the soil samples in strongly polluted to moderately polluted categories for Br, Sb, Pb and Zn. The results of the modified degree of contamination revealed that the soil samples fall between 3.8 £ mC d £ 5.8 indicating very high degree of contamination. Also, Pollution Load Index values showed that all the studied sampling sites were polluted.

Contamination of urban soils can affect the health of people living in urban areas, and the surrounding ecosystems. Urbanization in Iran during the last three decades causes more pollution in major cities such as Ahvaz. The aim of this study is environmental assessment of heavy metal contamination in Ahvaz road side soils. In this study 54 soil samples (Depth from 0- 20 cm) were collected in double side of road side soils in nine junctions (Modares, Zergan, Charshir, Behbahani, Golestan, Khoramshahr, Ahbadan, Sousangerd and Andimeshk) with distances of 1m, 10 m and 30m away from main road, collected samples were then determined by XRF (Lead, Zinc, Copper, Nockel and Chromium) and atomic absorption (Arsenic and Cadmium). The concentration of Cd, Cu, Pb, Zn showed a decreasing trend with increasing distance from the road while such trend was not identified in As, Cr and Ni. The soil samples from Modares and Charshir with highest traffic volume had the highest heavy metal concentration. According to the pollution index (PI) road side soils have highest Cd concentration was considered to have considerable contamination in Ahvaz roadside soils, while Cu, Pb, and Zn, Pb, Zn and Cu, but As, Ni and Cr none. In comparison with other cities such as Beijing with higher population in the world Ahvaz road side soils have considered pollution, it may be because of weathering pollution and other industrial activities.

There are signs of phyllic argillic and propylitic alterations in the Neysian area, 73 km of Northeastern of Isfahan province, based on the remote sensing findings which make it possible to look for porphyry copper and molybdenum deposits. This research aims to determine the copper and molybdenum anomal areas based on the analysis of 945 geochemical data from soil samples in the Eastern of Neysian. To fulfill this task, random sampling from the size of 40-60 mesh was conducted on profiles and the samples were analyzed by ICP-MS for 43 elements. The statistical calculations such as pre-processing, censored data replacement, corrections of out-layer data, and normalization and then multivariate statistical approaches were conducted on data. The separation of anomaly from background was achieved by traditional and P.N methods. The results have been validated by anomaly checking. The obtained results confirmed the existence of porphyry copper and molybdenum deposits. Based on gold enrichment in some areas, it is possible to look for the epithermal gold deposits as well.

The study area is located 110 kilometers East of Isfahan, Near the Jeshuqan village. This area is the part of Urumieh- Dokhtar belt in Central Iran. In this area there are a series of Eocene volcanic rocks. The composition of these rocks are andesite and dacite. Plagioclase amphibole, quartz are the main Phenocrysts in dasite rocks. Plagioclase amphibole, quartz are the main Phenocrysts in dasite rocks. The andesitic rocks consist of porphyritic textures with plagioclase and amphibole as the main mineral constituents with pyroxene for accessory mineral. Secondary minerals such as chlorite, calcite, epidote and iron oxide exist in both types of rocks. Sieve texture and selective alteration in plagioclase, opacitization of amphibole are very common in these rocks. Based on geochemical data, these rocks are calc- alkaline series. diagrams indicating tectonic environment represents a tectonic environment of continental volcanic arc. REE pattern and Pb positive anomalies also refers to cont- amination of the magma with continental crust.

Howz-e-sefid zinc- lead deposit is located 17 km northeast of Ardakan town in the central Iran tectonic zone.Cretaceous carbonate rocks consisting of three formations including Sangestan, Taft and Abkoh are host rocks of this deposit. The Sangestan formation, the lowest unit, is composed of shale and siltstone with calcarenitic interbeded layers. This unit is overlain by ankeritic massive dolomite and dolomitic limestone of Taft formation. The Abkouh formation at the top is composed of cherty or argillaceous limestone with massive reefal limestone. Deposit includes two types of mineralization: supergene in surface and sulfides in depth. The ore minerals paragenesis is composed of galena, sphalerite, pyrite, hemimorphite, smithsonite, cerussite and barite. Two main geometries for ore body have been recognized: 1) concordant layers and lenses; and 2) discordant veins along the fractures. Grade of Ag and Cd in mineralized samples is high and they can be considered as a by- product. Cadmium shows positive and good correlation with Zn, Sb and S, but correlation between Sc and Pb is weak and negative. This can represents the substitution of cadmium in sphalerite. All accomplished investigations such as geological characteristics, mineralized facies, supergene and sulfide development, ore mineral paragenesis, texture and structures in different scales, existing alterations specially dolomitization and geochemical studies reveal that the most features of the Howz-e- sefid zinc- lead deposit is a Mississippi Valley Type (MVT) deposit.