Economic Geology
Mona Mahdevari; Fardin mousivand; Mahmoud Sadeghian; Mehdi Movahednia
Abstract
Kuhe Rig iron- strontium-(manganese) deposit is located in south of Shahrood, in the northern part of the central Iran zone. Mineralization occurred in the Eocene volcano-sedimentary sequence dominated by andesite basalt, basalt and crystal lithic tuffs. Geometry of main ore body is lense-shaped which ...
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Kuhe Rig iron- strontium-(manganese) deposit is located in south of Shahrood, in the northern part of the central Iran zone. Mineralization occurred in the Eocene volcano-sedimentary sequence dominated by andesite basalt, basalt and crystal lithic tuffs. Geometry of main ore body is lense-shaped which is concordant with lithic tuff host rock layering. Vein-Veinlet mineralization occurs beneath the main ore lense. Based on stratigraphic position, mineralogy, and texture of mineralization, three different ore facies can be distinguished: vein-veinlet (feeder zone), bracciated ore and banded ore facies. Ore minerals includes: goethite, hematite, magnetite, celestite, pyrolusite, psilomelane, barite and iron hydroxides which are accompanied by calcite and quartz gangue minerals. Sericitization and chloritization are the main wall-rock alteration styles. Based on volcono-sedimentary host sequence, geometry of ore body, ore textures and facies, mineralogy, alteration zones and geochemical features, Kuhe Rig can be classified as volcanic-exhalative iron deposits. It's worth mentioning that high amounts of celestite is of special characters of the mineralization in Kuhe Rig deposit and any similar deposits has not been reported in Iran and the world.
Economic Geology
Rahimzadeh Bahman; M. Movahednia
Abstract
The Kamyaran manganese is located in the 20 km from NW of Kamyaran and south of Kurdistan province. In geological structure map these Mn-deposite are outcrops in Zagros and northern Sanandaj-Sirjan collision zone and close to Zagros ophiolites. In this area, Mn-mineralization occurs as regular lenses ...
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The Kamyaran manganese is located in the 20 km from NW of Kamyaran and south of Kurdistan province. In geological structure map these Mn-deposite are outcrops in Zagros and northern Sanandaj-Sirjan collision zone and close to Zagros ophiolites. In this area, Mn-mineralization occurs as regular lenses and interlayers with radiolarian cherts within the Eocene radiolarite and shale. The present work has been done based on field geology, mineralogy and geochemistry characterization. Study of Mineralogy and texturally Kamyaran Mn-ores show two stage mineralization including Braunite and Okhotskite were formed singenetic and pyrolusite was formed diagenetic. The high rate of Si and rhadiolarite fossils in Mn-bearing cherts suggest that the Kamyaran Mn-deposit was formed in deep oceanic area. The Variable content of Mn/Fe and high rate of detector element such as Ba and Sr revel the hydrothermal source for mineralization. Despite, Existence rhadiolarite fossils, sub-bedding deposits and some geochemical characterization suggest the sedimentary origin for Kamyaran Mn-deposit.
M. Movahednia; E. Rastad; R. Rajabi; F. J. González
Abstract
The Ab-Bagh Zn-Pb deposit is located at the southeastern part of the Malayer-Esfahan metallogenic belt. This deposit is hosted by Upper Jurassic-Lower Cretaceous sedimentary sequence. Zinc and lead mineralization occurred within two horizons. The ore horizon 1 is hosted by Late Jurassic-Early Cretaceous ...
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The Ab-Bagh Zn-Pb deposit is located at the southeastern part of the Malayer-Esfahan metallogenic belt. This deposit is hosted by Upper Jurassic-Lower Cretaceous sedimentary sequence. Zinc and lead mineralization occurred within two horizons. The ore horizon 1 is hosted by Late Jurassic-Early Cretaceous black shale and siltstone. The ore body displays a wedge-like shape and is located close to syn-sedimentary fault. The ore horizon 2 occurs in lower Cretaceous carbonates and includes massive ore,concordant with the host rock layering; Syn-sedimentary faults, half-graben basins and related anoxic environments, had an important role in formation of SEDEX-type Zn-Pb mineralization in the Ab-Bagh and deposition of sulfides. Sedimentary debris flows and syn-sedimentary braccia within host rocks of the Ab-Bagh deposit suggests activity of normal faulting simultaneously with sedimentation of host rock and consequently development of half- graben structures. Formation of half-graben structures is one of the most important factors of redox condition of ore forming environment. This structures led to development of deeper zones within the basin, where anoxic condition were occurred. Trace and rare earth elements geochemistry of host rocks, size of pyrite framboids and presence of organic matter in the host rocks, represent anoxic to euxinic paleo-redox condition of this basin, which is caused by microbial activities and depth of the basin,associated with normal syn-sedimentary fault. Comparison of syn-sedimentary normal faulting and anoxic formation environment of the Ab-Bagh deposit with other SEDEX deposit of Iran, indicates similarity of their formational environment.
