Economic Geology
Maryam Honarmand; Ghasem Nabatian; Mahtab Aflaki; Mohammad Ebrahimi
Abstract
Geology, geochronology and tectonic setting of the Moghanlou mylonite gneiss and granite bodies, west of Zanjan Abstract The Moghanlou mylonite gneiss and granite assemblage is located in the west of Zanjan forming a part of the magmatic-metamorphic association in the Takab area. The Moghanlou assemblage ...
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Geology, geochronology and tectonic setting of the Moghanlou mylonite gneiss and granite bodies, west of Zanjan Abstract The Moghanlou mylonite gneiss and granite assemblage is located in the west of Zanjan forming a part of the magmatic-metamorphic association in the Takab area. The Moghanlou assemblage comprises of leucogranite and biotite granite intrusions which have surrounded the gneiss body. The zircon U-Pb dating shows the ages of 563±6.5 Ma for the mylonite gneiss, 576±13 Ma for the biotite granite and 559±6 Ma for the leucogranite intrusions. Moreover, the samples from the Moghanlou assemblage display high-K calc-alkaline and slightly peraluminous affinities, except those from the leucogranite which are low potassium samples due to the sodic alteration and albitization of the K-feldspars. The trace element patterns suggest LILE and LREE enrichment and HFSE and HREE depletion as well negative anomaly of Nb, Ta and Ti. In general, the geochemical features of the Moghanlou intrusions are comparable with the melts formed from crustal partial melting in magmatic arc environment. The Moghanlou assemblage is analogues to other Late Neoproterozoic-Early Cambrian igneous and metamorphic associations in Iran and Turkey which are related to the igneous activity along the Cadomian magmatic arc, in north of Gondwana supercontinent.
Economic Geology
Amir Naderi; Ghasem Nabatian; Maryam Honarmand; Hossein Kouhestani
Abstract
Halab manganese deposit is located in the Sanandaj- sirjan zone, 100 km southwest of Zanjan. The rock units in the study area include Precambrian Kahar and Jangoutaran marble Formations. Manganese mineralization in the Halab area, occurred as veins and massive in the Jangoutaran marble and minor amount ...
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Halab manganese deposit is located in the Sanandaj- sirjan zone, 100 km southwest of Zanjan. The rock units in the study area include Precambrian Kahar and Jangoutaran marble Formations. Manganese mineralization in the Halab area, occurred as veins and massive in the Jangoutaran marble and minor amount in the schist unit. The main important minerals in the Halab manganese mineralization consist of pyrolusite, psilomelane, manganite and goethite, which calcite and quartz occurred as associated gangue minerals. The ore textures include cloform, vein-veinlets, massive, comb, dogtooth, botryoidal, replacement and relict. Actinolite, carbonate and silicic are the main important alterations in this area. Primitive mantle normalized of the rare earth elements (REE) patterns in the orebody and hydrothermal carbonate samples show that the samples relatively enrichmed in light REE. The analyzed samples show significant negative anomaly in Ce and weak negative anomalies in Eu. Furthermore, the primitive mantle normalized pattern of trace elements in the orebody and hydrothermal carbonate show significant enrichment in Ba, U, La, Pb, Sr and negative anomaly in Rb, Th, Nb, Ce, P, Zr and Ti. The field and microscopic studies as well geochemical evidences suggest that the mineralization formed by hydrothermal fluids. The circulation of meteoric and/or magmatic fluids within the Precambrian units provide the important elements such as Mn, Fe and Ca for mineralization. When the mineralizing fluid contact with reactable rocks, caused the formation of Mn mineralization in the Halab area.
Economic Geology
Mahin Zolfaghari; Ghasem Nabatian; Amir Morteza AzimZadeh; Maryam Honarmand; P. Azizi
Abstract
Pirgheshlagh Cu-Zn-Pb deposit is located in the Central Iranian zone, north-east of the Mahneshan in the Zanjan province. The Kahar Formation with Precambrian age is the oldest Formation in the area which cutted by the granitic dykes. The Pirgheshlagh Cu-Zn-Pb mineralization occurred mainly as tabular-shape ...
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Pirgheshlagh Cu-Zn-Pb deposit is located in the Central Iranian zone, north-east of the Mahneshan in the Zanjan province. The Kahar Formation with Precambrian age is the oldest Formation in the area which cutted by the granitic dykes. The Pirgheshlagh Cu-Zn-Pb mineralization occurred mainly as tabular-shape within the metamorphosed sandstones, meta-andesitic tuff, meta-crystal lithic tuff and meta-andesite rocks. Based on the field and microscopic studies, the main minerals consist of chalcopyrite, sphalerite, galena, pyrite, arsenopyrite and minor magnetite. The ore textures consist of disseminated, laminated, massive and veinlet which the veinlet texture is occurred mainly in the lower part of deposit. Secondary minerals such as smithsonite, cerrusite, chalcocite, covellite, malachite, azurite, goethite and lepidochrosite have formed during supergene processes. The main alterations in the Pirgheshlagh deposit include silicic, sericitic, chlorite and carbonate. The results of this study suggest that the Cu-Zn-Pb mineralization in the Pirgheshlagh deposit is a Besshi-type valcogenic massive sulfide (VMS) mineralization.
