جستجوی مقالات مرتبط با کلیدواژه « میامی » در نشریات گروه « زمین شناسی »

In recent decades, various methods have been developed for mineral exploration. Geophysical methods are one example, which have seen significant development in recent years and have become a common approach in the field of mining exploration, particularly in Iran. The objective of this study is to investigate the exploration area of Chahshen in terms of the potential for copper mineralization using geophysical methods and to identify promising areas for drilling. During field visits, it was observed that the main mineralization on the surface is of the oxide type, specifically malachite and azurite. Therefore, to explore the potential expansion of sulphide mineralization at greater depths, induced polarization and resistivity methods were employed. For this purpose, a rectangular array with a data collection distance of 20 meters and a line distance of 40 meters was used to determine the general trends in the region. Subsequently, six profiles were designed and measured using dipole-dipole and pole-dipole arrangements at 20-meter intervals. Through modeling of the studied sections, two-dimensional models depicting chargeability and resistivity were generated. The two-dimensional models indicated that the eastern regions exhibited more anomalies. However, due to the relatively weak nature of these anomalies, the possibility of developing a sulphide zone at shallow depths was detected. To validate the obtained results, drilling points were proposed. Profile 1 suggested a drilling point at station -10 with a depth of 45 meters, while profile 2 proposed a drilling point at station -10 with the same depth.

Dochileh copper deposit is located 72 km east of Shahrood, 15 km east of Mayamey, in North Central Iran volcanic belt. The stratigraphic sequence of the region comprises a considerable amount of volcanic and volcanic-sedimentary deposits of Eocene. these deposits are locally covered by Neogen and Quaternary deposits. The volcanic rocks hosting mineralization are composed of different rocks including basalt, andesite basalt and trachy andesitebasalt rocks that often contain plagioclase and clinopyroxene phenocrysts. The copper mineralization mostly occurred along the faults and fractures with the dominant trend of NW-SE in the basaltic rocks as vein-veinlets and open space fillings. Ore minerals including primary native copper and hematite, and secondary minerals such as malachite, goethite, hematite. gangue minerals such as calcite, zeolite and analcime. The wallrock alterations in the host rocks include chloritic, carbonatic, analcime-zeolite and iron oxide. The oxidation of mafic minerals such as pyroxene and magnetite were responsible for copper reduction and hematitic alteration. Geochemical investigation indicates that amounts of Cu and Ag are up to 5.11 wt% and 7.8 ppm, respectively. According to field studies, mineralogy and alteration, the Duchileh copper deposit appears to be formed during diagenesis and burial metamorphism, and dominantly during the orogeny and uplift processes, due to enterance of hot ore fluids along the fractures and faults perpendicular to the fold axis. The Duchileh deposit have a large resemblance to the basaltic copper or Michigan-type copper deposits in terms of tectonic setting, host rock, mineralogy, metal content, alteration and ore controls.

Granitoid plutons of SW Mayamey (60 Km east of Shahrood), located at the most northern margin of the central Iran structural zone, have granite composition (in general) and calk alkaline and peralouminous nature. In spite of coverage of these granitoids by Late Triassic – Early Jurassic sedimentary rocks, Late Neoproterozoic host gneiss are exposed in limited areas. These granitoids invaded by two series of the Late Neoproterozoic and middle Jurassic diabasic dikes. Although post – Liass, Pre- Dogger, younger than Jurassic and older than Cretaceous ages are considered for these granitoids, but for the first time U–Pb age dating on separated zircons indicates Late Neoproterozoic age (Late Ediacaran) (545±10 Ma) for them and they are a part of very ancient basement rocks of Iran. The studied rocks are similar Band -e-Hezar Chah, Sefid Sang, Delbar, Shotor Kuh, Reza Abad and Do Chah granitoids in age. Mayamey granitoids are resulted from partial melting of metapelites and metagraywackes, and they belong to S-type granioids. SW Mayamey granitoids were generated in a collisional tectonic setting in the Late Neoproterozoic, in relation to closing of intracontinental back arc basin and then metamorphism of the associated rocks from greenschist facies to amphibolite and rarely granulite facies, which finally companied with s-type granitization