School of Geology

The Permian rocks in Gaduk Area (east of Firuzkuh, Central Alborz) occur as a mixed siliciclastic-carbonate succession, dominated by siliciclastic facies (Doroud Formation) in the lower and carbonate facies (Ruteh Formation) in the upper half. This succession overlies the Lower Carboniferous Mobarak Formation and is underlain by Lower Triassic carbonates of Elikah Formation unconformably. Field studies and Laboratory measurements resulted in recognition of 4 terrigenous and 13 carbonate facies in the studied section. Siliceous cemented oligomictic orthoconglomerate and quartzarenite, calcite cemented quartzarenite (Lc–bearing in places), and red siltstone are common terrigenous facies. Fair laminated homogenous dolomite to lime mudstone, peloid grainstone/packstone, bioclast oncoid grainstone/packstone, bioturbiated bioclast wackestone/packstone, sandy ooid grainstone, green algal bioclast grainstone, sandy bioclast grainstone/rudstone, oriented sandy bioclast packstone, sandy bioclast floatstone, cephalopod bioclast wackestone and sponge spicule bioclast wackestone are common carbonate facies. A homoclinal carbonate ramp, with scattered patch reefs and a siliciclasticshallow marine system (siliciclastic shelf) were interpreted as depositional environment of the carbonate and terrigenous facies respectively. Results from this study show that sedimentation in the area commenced with siliciclastic facies, after the early Permian eustatic sea-level rise. This shelf was gradually changed into a carbonate ramp setting mostly due to relative sea level rise, result of which occurred as development of Middle Permian deposits. Lack of Upper Permian deposits is related to a regional sea level fall, which resulted in development of a laterite horizon in the area.

The origin of the Proterozoic Choghart iron oxide deposit in the Bafq mining district of Central Iran has been the subject of a long-standing dispute. Some authors believe that it was formed from magma, while others suggest metasomatic
replacement of preexisting rocks. The present study on the basis of new oxygen isotope, REE and geochemical data concludes that neither of these two hypotheses can alone explain the formation of Choghart deposit. Instead, it is suggested that the separation of an iron oxide melt and the ensuing hydrothermal processes dominated by alkali metasomatism were both involved to different degrees in the
formation of Choghart and other similar deposits in Central Iran.

Zarshuran deposit is the most famous and important As-Au mine in Iran. However, there is no information on the impact of mining activity on the surrounding environment, especially on water systems. This paper attempts to document the concentration of arsenic and associated elements in waters and sediments resulting from the mining history of Zarshuran, a period covering hundreds of years. Water and sediment samples collected from Zarshuran Stream indicate high content of some potentially toxic elements, especially of As which ranges from 0.028 to 40 ng/l in water and 182 to 36,000 mg/kg in sediment samples. Mining activity, exposure of a large volume of mining wastes to weathering, and the anomalously high background of trace metals in the mining area are considered to be the main sources of heavy metal pollution.

Concentrations of heavy metals (As, Co, Cu, Ni, Mo Pb and Zn) are studied in the soil of Shiraz industrial complex zone, south Shiraz, Iran to assess metal contamination due to industrialization, urbanization and agricultural activity. Soil samples were collected from three different depths. The A and C depths are enriched with metals such as Ni, As, Mo, Cu, Pb, and Zn, compared with the B depth. The average abundance order of heavy metal contents in soil depth are: Ni > Zn > Cu > Co > Pb > As > Mo. Soil contamination is assessed on the basis of contamination factor (CF) and modified degree of contamination (mCd). The CF and mCd base of background values in the three sampled depths for Cu, Zn, Co, Ni, Mo and As are moderate. Pb reveals considerable contamination. The results of enrichment factor (EF) show that using Sc concentration in the average shale produces higher average EF values for Ni, Co and Mo as compared to average values determined using the actual Sc content in lower core baseline values (background). The results of the principal component analysis (PCA) show Zn, Co, Ni, Sc, Cu, Al and Fe come from a similar source and are not influenced by anthropogenic sources. High loading of Zn, Co, Cu, and Ni with clay, Al and Fe indicate the active role played by Al and Fe hydroxides and clay content on distribution and sorption of the studied heavy metals in soil. Also, PCA results indicate that As, Mo and Pb behave differently at different depths.

The concentrations of potentially toxic elements (As, Sb, and Hg) and some trace elements in 36 topsoil samples and 18 agricultural soil samples were measured at the Aq-Darreh River watershed, NW Iran. Based on the results of the chemical analysis and comparing them with different standards, it seems that the soils of the Aq-Darreh River watershed are polluted with As and Sb. This pollution results from geochemical background (natural contamination) and mining activities. Geochemical background values in topsoil and agricultural soils were estimated for As (429.7 ppm and 98.8 ppm), Sb (79.02 ppm and 3.98 ppm), and Hg (356 ppb and 2596 ppb). This research also indicates that mining activities have played a significant role in soil pollution and increasing As, Sb and Hg concentration in topsoils and As and Sb in agricultural soils. Results of sequential leaches and XRD analyses of both soil types showed that most of the As concentration is bound to amorphous iron hydroxides in soils, while Sb and Hg are bound to resistant minerals such as stibnite and cinnabar. Clay and carbonate minerals have a lower adsorption of these pollutant elements in both topsoil and agricultural soils.

Zarshuran As-Au deposit is the major ore deposit in northwest of Iran. Having been exposed to weathering, the accumulated mining waste is consumed to deteriorate regional soil and water quality. Accordingly, 11 composite surface soil samples were collected to evaluate the metallic pollution. Mean concentration of elements As, Sb, Hg and Zn were measured to be 234.9, 19.6, 24.2 and 476.7 ppm, respectively. In comparison with mean earth crust and local guidelines for agricultural soil, the samples are strongly polluted by toxic elements As, Sb, Hg and Zn. The major reason of such high pollution may be contributed to the lasting gold mining activities that ease the exposure of Au-As-Sb rich minerals to the air and moisture. Detailed statistical analysis categorizes the 11 stations into two distinct groups. Stations S1 to S5 (showing lower metallic pollution) belong to the first group and are located in higher elevations than the mining site. Being located in downstream of the mining site, stations S6 to S11 (second group) manifest more severe soil quality degradation. The seasonal inundation of regional river waters plays the key role in polluting the downstream soil. Regarding extremely high concentrations of toxic elements (As, Sb, Hg and Zn) in the soil of the study area, severe threats may be posed to human health through consumption of the harvested crop.

The main aims of this paper are to investigate the geochemistry and determination of source of trace elements of As, Mo, V, Ni, Cu, Cr, Co, and S in bituminous shales and limestones of Chahar Mahal Province using multivariate statistics e.g. factor analysis, principal component analysis, cluster analysis and enrichment factor. Chemical analysis data using AAS method and statistical analysis indicate that mean concentration of trace elements are much higher than the mean global values especially for Mo, Ni and V which is 763, 284 and 904ppm in Zarak area, 832 , 295 and 800ppm in Saleh kootah and 698, 292 and 987ppm in Khouyeh areas respectively. Correlation matrices for trace elements show elements with geochemical relationship and correlation in study areas as follow: Co, As, S, Mo, V, Ni and Cu have strong correlation coefficients higher than 0.7 in Zarak area, Mo, Ni, Cu, As and S in Saleh Kootah and Mo, V, Ni, Cu and Co in Khouyeh area. Multivariate statistical parameters were used for discriminating the elements into different categories based on their sources. In Zarak area elements Mo, V, Ni, Cu, Cr, Co, As and S we grouped in component 1 showing a common source while they also show association with organic matter and they could be related to adsorption on bituminous matter. In Saleh Koutah Mo, Ni, Cu, Cr, As and S were clustered in component 1 and Co and V are gathered in component 2. The first component is related to adsorption and the second one to detrital load from the continent. In Khouyeh area, Mo, As, Co and Cu are clustered in P1 and Cr, Ni and V in P2 indicating a dual source like the Saleh Koutah area. Other statistical parameters also are in accordance to PCA.

Analysis of the spatio-temporal patterns and source apportionment of water pollution is important for proper management and protection of water resources. In this paper, different multivariate statistical methods were used to explore the spatio-temporal patterns of water pollution, and quantitative relationships between the important pollution parameters and environmental variables. Eleven significant parameters measured in 22 monitoring sites were preprocessed spanning between 2001 and 2007. Results of the hierarchical clustering analysis (HCA) demonstrated that this method had high flexibility for efficient classification of the monitoring sites. Results of discriminant analysis (DA) revealed that a high number of parameters contributed in discrimination of classes in the spring and summer seasons, especially in the April and September months. Recorded data of river water temperature (RWT), runoff, and two products of the MODIS sensor including the monthly Normalized Difference Vegetation Index (NDVI) and land surface temperature (LST) for the period of 2002-2007 were used as the explanatory variables. Test of NDVI and LST was based on extraction of their average values in different buffers of 250 up to 1500 m around the streams. Monthly data of group 1, a group with the highest number of monitoring sites resulting from the clustering procedure, was used for the analysis. Rotated principal component analysis (rotated PCA) was used for exploration of the quantitative relationships between the pollution parameters and environmental variables. Absolute principal component score-multivariate linear regression (APCS-MLR) was applied to quantify the source contributions for each pollution parameter. Results showed that NDVI and runoff can be considered as the efficient indicators of the non-point pollution sources such as the agricultural activities and surface weathering. NDVI showed an important role in reduction of TDS and No . Multiple buffers of NDVI showed temporally variable relations with different pollution sources. LST showed high discrimination potentials for distinguishing pollutions related to biochemical activities. Although the tested environmental variables revealed some relationships with those of the water pollution sources, nevertheless for more detailed analysis of the water pollution problem, the role of other latent environmental variables should be taken into consideration. Index Terms-Absolute principal component score-multivariate linear regression (APCS-MLR), hierarchical clustering analysis (HCA), latyan dam basins, Moderate Resolution Imaging Spec-

Thermal springs are widely used by tourists for treatment of dermal diseases and other therapeutic applications. In Iran, thermal springs occur in Northwestern part mainly surrounding the Mount Sabalan which attract hundreds of thousands of tourists annually. Two clusters of springs in Neer and Meshkinshahr areas including 16 thermomineralic springs have been studied in this research and they were sampled twice in May and November in order to investigate the seasonal changes of trace elements in dry and wet seasons. The samples were analyzed in Acme Lab, Canada for 72 elements. Trace element concentrations indicate that most of the elements show concentration well beyond the guideline values for drinking water. While the two sets of samples were taken within a 6 months interval, the elements show slight or no variation from first period to the second and in some cases. Arsenic shows a variation of 5-5834μg/l and the mean As value is 160 times the guideline values (10 μg/l). Other toxic elements with high concentration are B, Fe, Mn, Sb, and Si. Mn and Sb shows exeedance of 12 and 11.5 times respectively. Correlation coefficient and principal component analysis of analytical data indicate that Cl, As, B, Ba, Br, and V show very strong mutual correlation coefficients implying their relationship and common source and fate in the hydrothermal fluid carrying them. These elements fall in the component 1 of PCA. This group of elements is supposed to be derived and sourced from the magmatic-hydrothermal system and through the interaction of hydrothermal fluids with rocks they passed through. Because of discharge of the thermal springs into the nearby streams intended to be used for drinking water and also vast application of spring waters in balneological uses, they may have adverse environmental and health impacts on tourists that expose themselves to this contaminants through balneological applications. This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2 0 , which . permits unrestricted use, distributi and reproduction in any medium, provided the original work is properly cited.