M Lotfi; M Hekmatian; A.A Shabani; M.A Mokhtari
Abstract
Oras-kuh lead-zinc deposit is located at about 79 km north-east of Semnan city. This deposit is considered as stratabound and occurs in the upper part of the Triassic dolomitic limestone of the Elika formation. Oras-kuh structure includes a northeast - southwest trending normal anticline and follows ...
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Oras-kuh lead-zinc deposit is located at about 79 km north-east of Semnan city. This deposit is considered as stratabound and occurs in the upper part of the Triassic dolomitic limestone of the Elika formation. Oras-kuh structure includes a northeast - southwest trending normal anticline and follows the general trend of the eastern Alborz. Folding in the area has generatedthree sets of jointsincludingjoints trending parallel to the direction of anticline axis, extensional joints perpendicular to anticline axis and the conjugate joint systems. The first two setsof the joints host vein form mineralization. In addition, breccia and karst filling mineralization can be detected. Major minerals are galena, sphalerite and pyrite that altered to secondary minerals such as cerussite, goethite, hydrohetarolite and rosasite under the supergene processes. Gangue minerals are dolomite, calcite, barite, quartz, and small amounts of fluorite. The majority of the temperature data are between 298 to 323°C based on the fluid inclusion geothermometry of calcite and barite minerals. The relatively high temperatures of fluid inclusions are attributed most likely to a concealed deep intrusion in the crust inferred byairborne geomagnetic survey. Fluid salinities show a wide range from 0.6 to 15wt% equivalent weight of NaCl formed through mixing of basinal brines with meteoritic water. In general based on the present evidences, Oras-kuh lead-zinc deposit can be comparable with MVT deposits that its primary mineralogy and elemental ratios have been changed through secondary supergene processes.
Z Miriyan; M Lotfi; A.A Shabani; M.A.A Mokhtari; E Haj Molla Ali
Abstract
The Kharengun area is located in the Yazd province, Central Iran, 130 km east of Yazd city and 65 km northeast of Bafq city. Mineralization in Kharengun area occurred within calcic and dolomitic units of the Rizou Formation (equivalent to Soltaniyeh Formation) of upper Precambrian- lower Cambrian age. ...
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The Kharengun area is located in the Yazd province, Central Iran, 130 km east of Yazd city and 65 km northeast of Bafq city. Mineralization in Kharengun area occurred within calcic and dolomitic units of the Rizou Formation (equivalent to Soltaniyeh Formation) of upper Precambrian- lower Cambrian age. The ore minerals of this deposit includes smithsonite and hemimorphite, that is stratabound and formed epigenetically along layers and laminations of carbonate host rocks. The maximum grade of zinc in samples taken from the study area exceeds 36% and geochemical studies indicate significant absence of Pb along with Zn in this area. Therefore, the Kharengun mineralization is a monomineral Zn zone.The fluid inclusion microthermometry investments explain the role of meteoric waters in generation of this deposit. The homogenization temperatures and salinity of the inclusions show the similarity between these fluids and the solutions responsiblefor the development of epithermal deposits.The Zn mineralization present in this zone belongs to the nonsulfide supergene deposit class, and a mixture of wallrock replacement and direct replacement subclasses.
