Farsesh barite in the central part of Iranian SanandajSirjan zone is a sample of epigenetic hydrothermal mineralization in dolomitized limestone, which provides appropriate chemicophysical conditions making the passage of mineralbearing fluids possible. Barite veins may range from a few centimeters to 2 m in thickness that increases downward. The microthermometry measurements obtained from more than 30 fluid inclusions show relative homogenization temperatures ranging from 125 to 200°C with an average of 110°C for Farsesh barite deposits. The mean salinity measured proves 16 times as much as weight percentage of NaCl for barite. Coexistence of liquid-and vapor-rich fluid inclusions in barite minerals may provide an evidence of boiling in ore veins. Moreover, occurrence of bladed calcite, high-grade ore zones, and presence of hydrothermal breccia are all consistent with boiling. Thermometric studies indicate that homogenization temperatures (Th) for primary and pseudosecondary fluid inclusions in barite range from 125 to 200°C with an average of 1,100°C. The δ 34 S values of barite also lie between 8.88 and 16.6 %. The relatively narrow spread in δ 34 S values may suggest uniform environmental conditions throughout the mineralization field. Thus, δ 34 S values are lower than those of contemporaneous seawater, which indicates a contribution of magmatic sulfur to the ore-forming solution. Barite is marked by total amounts of rare Earth elements (REEs) (6.25-17.39 ppm). Moreover, chondrite-normalized REE patterns of barite indicate a fractionation of light REEs (i.e., LREEs) from La to Sm, similar to those for barite from different origins. The La CN /Lu CN ratios and chondrite-normalized REE patterns reveal that barite in Farsesh deposit is enriched in LREEs compared with heavy rare Earth elements (HREEs). Similarity between Ce/La ratios in barite samples and those found in deep-sea barite supports its marine origin. Lanthanum and Gd exhibit positive anomalies, which are common features of chemical marine sediments. Cerium shows a negative anomaly in most samples inherited from the negative Ce anomaly of hydrothermal fluid that is mixed with seawater at barite precipitation. The available data including tectonic setting, host rock characteristics, REE geochemistry, and sulfur isotopic compositions may support a hydrothermal submarine origin for Farsesh barite deposit.
The studied subject is about subsidence coefficient of mirages and dynamic storage volume of Karstic springs in Khorram Abad in West of Iran. Subsidence coefficient indicates ability of groundwater discharge and hydrologic properties of the environment; meaning effective porosity and transfer coefficient of springs. In general, in developed Karstic zones, each direct line of subsidence curve indicates a discharge regime. Obtained results from the study show that subsidence branch of Golestan, Motahari, Niloofar (changaei), Navekech, Dore Robat mirages have subsidence coefficient with mild slope and low value, which demonstrate passage of water through a seams system at the karst springs. Q and whirlpool stone mirages have two subsidence coefficients, which indicate passage of water through two seam systems in Karstic environment of springs. According to obtained results, process of changes in subsidence branch in these mirages has had at the first a mild slope and low discharge coefficient and in continue, its discharge would be declined with sharper slope and high discharge coefficient. In order to estimate dynamic storage volume of springs, MAILET general equation is applied, which is suitable for subsidence branch of hydrographs of centralized springs discharge. Following, dynamic storage volume of studied springs is analyzed and obtained results are presented in this study respectively.
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