behzad hajalilou

In the Gezeldash_daghi region, there is a significant outcrop of Miocene volcanic activity with andesitic composition associated with pyroclastic deposits including tuff, breccia and agglomerate. These rocks have porphyry to microporphyry texture with coarse crsytals of pagioclase, and matrix includes plagioclase, hornblende and minor biotite. Zoning, sieve texture in the coarse crystals of these lavas is an indicative of unstable conditions during magma solidification. These lavas have calc-alkaline nature. The geochemical characteristics of Gezeldash_daghi lavas such as LREE enrichment than HREE as well as enrichment of LILE elements with negative Nb, Ti and P anomalies indicate their affilliation to subduction setting. These rocks contain high amounts of SiO2, Sr, Sr / Y and La / Yb, and lower values of Y, MgO, and Yb than classic calc-alkaline volcanic rocks, and may indicate lava adakitic features. Based on the geochemical data, these lavas had formed partial melting of subducted oceanic crust. The depletion of rare earth elements indicates a residue containing garnet and hornblende in the source area.

The placer ore deposit of Ataeieh is located in south west of Mashhad and central Iranian microplate. The petrography and mineralography studies of VTM placer ore deposit, showed that the main ores in this area from high to low amounts are: magnetite, titanomagnetite, hematite and ilmenite. It revealed that the ultramafic and gabbros are the main source for opak minerals by mineralography Studies. The SEM-EDS, EPMA and XRM studies on the placer ore deposit and their origion presentaded remarkable results. The SEM investigation showed that, in the magma crystallization the solid soulution is formed between titanomagnetite and ilmenite at 800°C and then with the decreasing of temperature up to 600°C the ilmenite and magnetite exsolution lamella segreqates and separated from titanomagnetite phase either the ophiolite sequence is the source of this deposit. Titaniumand Vanadium enter to the ilmenite and titanomagnetite in gabbroic rocks whit continuing of magma crystallization. The EPMA analysis on gabbroic units showed that these rocks are origion for Ti and V in placers.

It is generally understood that manganese deposits have a diverse origin, based on their mineralogy, chemical composition and tectonic setting. Marine Mn-bearing deposits are classified as hydrogenous, hydrothermal and also biogenetic-bacterial deposits (Bonatti et al., 1972; Hein et al., 1997; Bau et al., 2014; Polgári et al., 2012; Schmidt et al., 2014). Hydrogenous processes can form ferromanganese crusts, which result from slow precipitation of seawater at the seafloor often via microbial mediation (Toth, 1980; Dymond et al., 1984; Bau and Dulski, 1999; Usui and Someya, 1997; Hein et al., 2000; Jach and Dudek, 2005). Diagenetic manganese deposits occur as nodules and precipitate from hydrothermal solutions or pore water (Polgári et al., 1991; Oksuz, 2011; Polgári et al., 2012), whereas hydrothermal ore deposits are stratabound or occur as irregular bodies and epithermal veins, where they are formed in a marine environment near spreading centers, intraplate seamounts or in subduction-related island arc setting (Roy, 1992; Roy, 1997; Hein et al., 2008; Edwards et al., 2011).

Eighteen Ore samples (~ 500 g each) were collected systematically from the Gezeldash Daghi manganese deposit. All these ore samples were taken representatively from the surface outcrops ore beds in different places for geochemical analyses. Ore samples were powdered under 200 meshes and analyzed at Iran mineral processing research center laboratories, Tehran. After being prepared by the Lithium Borate Fusion method, their major oxide and trace element contents were determined with ICP-OES. The results of the analyses are given in Tables 1 and 2.

The deposit is hosted in various lithology and horizons consisting of: 1) tuffite interlayered with limestone, 2) conglomerate and sandstone lithology into volcano-sedimentary basin located at 25 km northwest of Marand city (N38°35ʹ40ʺ, E45°42ʹ40ʺ). Major and trace element assessments show that hydrothermal solutions were effective in the formation of the Gezeldash Daghi manganese deposit. Also, field observations reveal that manganese mineralization occurred as laminated-layered and fracture-filling form in limestone and tuffite at horizon I and the space-filling form between conglomerate clasts and veinlet form in sandstone at horizon II with quaternary age. Therefore, it can be concluded that hydrothermal solutions were caused in the formation of the manganese deposit which may be described as related to volcano-hydrothermal occurrence.

The mineralogy and geochemistry of Paleocene shales and interbedded siltstones in the southwestern of Ahar town (NW Iran) were studied by optical microscopy, XRD, SEM, XRF, and ICP-MS techniques. The mineralogical composition, mainly characterized by calcite, quartz, feldspar, dolomite, muscovite, magnesiohornblende, chlorite, illite, montmorionite, palygorskite, and koninckite, suggests relatively fast erosion of the parent rocks and incipient metamorphism for the studied sediments. The values of weathering indices and the Index of Compositional Variability, as well the mineralogy of the sediments imply moderate weathering in the parent rocks and deposition as first cycle sediments. The shales exhibit higher Al2O3/TiO2 (≈21), La/Sc, and Th/Cr values corresponding to felsic and/or intermediate source rocks. The geochemical character of sediments including ∑REE=116 ppm, (La/Yb)N=8.3, (Eu/Eu)=0.78, and the immobile elemental ratios values suggest an immature continental arc setting. The typical shale and chondrite normalized REE patterns of the shales are comparable with continental arc terrigenous sediments and Andean-type andesites. The inferred tectonic setting for the studied shale is in agreement with the tectonic evolutionary history of NW Iran during the Upper Cretaceous-Upper Paleocene. According to the present data, we conclude that the ultimate provenance of the studied shale and its interbedded siltstone and thin detritic limestone was probably the Upper Cretaceous sediments with the geoenvironment of acidic to intermediate volcanic rocks and marl.

In most parts of our country groundwater is the only source of water supply. During two last decades groundwater withdrawal changes hydrology cycle and has been creating numerous environmental hazards. In this paper، hazards related to groundwater depletion in Ardabil plain have been described. During last 15 years، indiscriminate discharge from alluvial aquifer of Ardabil plain and increasing 40% of the number of wells have caused decreasing of 8. 22 meters of water table، decreasing 22% of wells yield and increasing of 46. 7% groundwater salinity. Due to groundwater depletion and presence of inter layers of sand-gravel and clay-silt، there is the possibility of land subsidence in this plain. Inter basin water transformation (from upstream of Sefidrood river)، filling illegal wells and artificial recharge are operation guidelines to prevent the increasing trend in the groundwater depletion in Ardabil plain.

The study area is located about 3 km southwest of the Hormoz Island in the Hormozgan province، in the Persian Gulf. The main rock units in the region consist of a highly altered acidic pluton cratophyre، which is responsible for apatite formation، diabasic dike، marl and altered basalt. Apatite is the only phosphate mineral in the Hormoz Island، which has accumulated REE in its crystal structure. The amount of Na2O and SiO2 oxides in apatite are high and the average content of the main elements Fe، Mg، Al، Ca are 7. 5 ppm، 365 ppm، 2880 ppm and 27. 8%، respectively. The Y، Mn، Rb contents increase and Sr decreases with increasing magmatic differentiation. It shows that a moderate magmatic differentiation occurred during the crystallization of apatite. The total REE content in the Hormoz apatite is high (1. 22-2. 25%). LREE/HREE ratio is also high. This means that Hormoz apatites are enriched in light rare earth elements. The REE normalized pattern shows a negative slope with a negative Eu anomaly. According to various diagrams based on apatite composition، it is deduced that the Hormoz apatites belong to mafic I-type granitoids with high oxidation state (Fe2O3/FeO>1).

Remains of fossil herbivorous mammal from families like Elephantidae، Rhinocerotidae، Giraffidae، Bovidae and Equidae have been studied systematically from a new fossiliferous horizon from the Ilkhchi area in the southeastern high foothills of Sahand. Genera such as Hipparion، Gazella، Samotherium، Chilotherium and Choerolophodon and some undetermined specimens are identified and reported. Based on the position of the layer containing fossils، which is placed at the top of a volcanic (dacitic tuff) key bed and based on the absolute ages available from this key layer، a Late Miocene age is proposed for this fauna.

Pollution due to mining activities could have an important role in health and welfare of people who are living in mining area. When mining operation finishes, environment of mining area can be influenced by related pollution e.g. heavy metals emission to water resources. The present study was aimed to evaluate Valiloo abandoned arsenic mine effects on drinking water resources quality and possible health effects on the residents of mining area in the North West of Iran. Water samples and some limited composite wheat samples in downstream of mining area were collected. Water samples were analyzed for chemical parameters according to standard methods. For determination of arsenic in water samples, Graphite Furnace Atomic Absorption Spectrometric Method (GFAAS) and for wheat samples X – Ray Fluorescence (XRF) and Inductively Coupled Plasma Method (ICP) were used. Information about possible health effects due to exposure to arsenic was collected through interviews in studied villages and health center of Herris City. The highest concentrations of arsenic were measured near the mine (as high as 2000 μg/L in Valiloo mine opening water). With increasing distance from the mine, concentration was decreased. Arsenic was not detectable in any of wheat samples. Fortunately, no health effects had been reported between residents of studied area due to exposure to arsenic. Valiloo abandoned arsenic mine has caused release of arsenic to the around environment of the mine, so arsenic concentration has been increased in the groundwater and also downstream river that requires proper measures to mitigate spread of arsenic.