Economic Geology
Zahra Akbari; ali yarmohammadi; Iraj rassa
Abstract
The Fe-Pb Ahangaran deposit, hosted by tuffaceous siltstone of the Early Cretaceous sedimentary sequence in the northern part of the Malayer-Esfahan Metallogenic Belt (MEMB), Iran. Ore mineralization occurred as stratiform and a widespread veinlet zone in the upper part of Lower Cretaceous terrigenous ...
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The Fe-Pb Ahangaran deposit, hosted by tuffaceous siltstone of the Early Cretaceous sedimentary sequence in the northern part of the Malayer-Esfahan Metallogenic Belt (MEMB), Iran. Ore mineralization occurred as stratiform and a widespread veinlet zone in the upper part of Lower Cretaceous terrigenous unit (Kc). Four different ore types can be distinguished in deposit include: (1) veinlet (feeder) zone, (2) sulfide-Fe- oxide stratiform ore (3) barite ore and (4) vein ore. Ore minerals in the different ore types are pyrite, siderite, magnetite, galena, barite, chalcopyrite and tetrahedrite and rare minerals are pyrrhotite, arsenopyrite, and freibergiteCarbonatization and silicification are the main hydrothermal alterations in this deposit. The orebodies in the Ahangaran deposit have been replaced by iron oxide minerals in supergene process and have been formed a thick gossan zone. The textural and mineralogical data provide evidence of three stages of mineralization (Early, main and late stage) in Ahangaran deposit. According to evidences such as tectonic setting, type of host rock, geometry of deposit, sulfide-Fe oxide ore types, textures and structures indicate that the Ahangaran deposit is compatible with a sub-seafloor replacement mineralization that has been suggested for some Sedex deposits.
Economic Geology
S. Amani Lari; I. Rassa; A. Amiri
Abstract
Ahmadabad Zn-Pb deposit is one of the Pb-Zn deposits in the Kouhbanan-Bahabad metollogeny Belt, which is located 10th Km northwest of Bahabad City in the Posht-Badam Block in Centeral Iran Zone. Ore deposits consist of Zn, Pn, Mo and Sr non-sulfide minerals with large amount of Fe oxide-hydroxide ...
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Ahmadabad Zn-Pb deposit is one of the Pb-Zn deposits in the Kouhbanan-Bahabad metollogeny Belt, which is located 10th Km northwest of Bahabad City in the Posht-Badam Block in Centeral Iran Zone. Ore deposits consist of Zn, Pn, Mo and Sr non-sulfide minerals with large amount of Fe oxide-hydroxide minerals occurred in dolomitic host rock of the Shotori Formation. A quartz-calcite vein accompanies ores in the host rock. This study is focused on C-O isotopic variation in the host rock, quartz-calcite vein and hydrozincite. Isotopic variation of C indicates that the source of carbon is different in the host rock and quartz-calcite vein. The most important source of carbon for hydrozincite formation was carbonate rocks of the area and regarding this aspect this deposit is different from others Zn-Pb non-sulfide deposits that studied in the world. According to oxygen isotopic variation, the temperature for hydrozincite formation was between 14-44˚C. The oxygen isotopic variation suggests marine basin water as the source of quartz-calcite vein. The dolomitic host rock was formed in equilibrium with fluids of a mixture of marine and magmatic waters, based on oxygen isotopic variation.
