Economic Geology
Mohsen Rezaei; Alireza Zarasvandi; Sima Basious
Abstract
Iju porphyry deposit is associated with the emplacement of Miocene tonalite-granodiorite intrusions (zircon U/Pb dating; 9.27±0.50) within Eocene volcanic and pyroclastic sequences including andesite, basaltic andesite, trachyandesite, andesitic breccias, tuffaceous breccias, and agglomerate. ...
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Iju porphyry deposit is associated with the emplacement of Miocene tonalite-granodiorite intrusions (zircon U/Pb dating; 9.27±0.50) within Eocene volcanic and pyroclastic sequences including andesite, basaltic andesite, trachyandesite, andesitic breccias, tuffaceous breccias, and agglomerate. In this study, occurrence and chemistry of magnetites in the potassic alteration of Iju deposit were assessed using EMPA analysis. The findings imply for a limited occurrence of magnetite as fine-grained disseminated and/or product of biotite chloritization. Magnetites associated with potassic alteration of Iju deposit don’t show hematite intergrowth (as martitizied margin) and anhydrite paragenesis, indicating the lack of high oxygen fugacity (near magnetite-hematite buffers; ~ΔFMQ+4) during the magnetite crystallization in the potassic alteration. Studied magnetites are high temperature (>500 °C) and according to the Mg + Al + Si contents crystallized under low rate of fluid rock interaction. These evidences accompanied with the absence of reequilibration processes could imply for the lack of repeated stages of hydrothermal fluid exsolving during the evolution of potassic alteration in the in the Iju deposit. Additionally, results represent that there are considerable values of Ga (average; 0.015 wt. %) in the studied magnetites providing insights into the presence of unseen exploration potentials associated with porphyry Cu deposits of UDMB.
Economic Geology
Alireza Zarasvandi; Mohsen Rezaei; Mansour Adelpour; Hadis Parvaneh
Abstract
Parkam (Sara) and Abdar porphyry Cu deposits containing mainly dioritic and quartz dioritic stocks are located in the southern part of Urumieh-Dokhtar Magmatic Belt (UDMB). In the Parkam deposit, alterations such as potassic, potassic-phyllic, biotitic, phyllic, argillic and propylitic have been identified, ...
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Parkam (Sara) and Abdar porphyry Cu deposits containing mainly dioritic and quartz dioritic stocks are located in the southern part of Urumieh-Dokhtar Magmatic Belt (UDMB). In the Parkam deposit, alterations such as potassic, potassic-phyllic, biotitic, phyllic, argillic and propylitic have been identified, while Abdar deposit is characterized by the limited extent of potassic alteration with widespread occurrence of phyllic alteration. The aim of this study is to characterize the phyllic alteration using sericite and sulfide (i.e., pyrite and chalcopyrite) chemistry. In this way representative phyllic alteration samples were analyzed using Electron Microprobe Analysis (EMPA). Results imply for higher concentrations of Zn, Ag, Au, and as in the chalcopyrite samples (averages in wt. %; 0.07, 0.007, 0.012, and 0.043; respectively). Comparably, pyrite samples exhibit higher concentrations of Re, Te, Co, and Mo (averages in wt. %; 0.01, 0.003, 0.09, 0.07; respectively. Among this, gold concentration in the pyrite samples of studied deposits is analogous to those reported previously for Meiduk porphyry Cu-Mo systems wherein gold occurs as inclusions, and/or nanoparticles (probably as Au0 or Au-telluride). In the both deposits, fine-grained micas are K-rich. Additionally, sericite samples exhibit an increasing trend of Si with Fe2+, Mg2+, and Al3+ substitution in the octahedral sites confirming the changes to celedontie - endmember. In accordance with other mineralized porphyry systems (i.e., Copper Cliff and Copper Flat deposits), most of the data follow the trend of ideal tschermak substitution occurring by the increasing of positive charges in the tetrahedral site of white mica owing to the increasing of Si substitution.
Economic Geology
Ali reza zarasvandi; Mohammad Ali Ali Abadi; Mohsen Rezaei; Houshang Pourkaseb
Abstract
The Mohammadabad deposit is located in vicinity of Delijan in central province and in terms of structural zones of Iran,in the Uremia dokhtar zone. Stratabound Fe-Ce mineralization in brecciated, vein, massive, layered and laminar forms, consists ore minerals such as hematite, pyrite, chalcopyrite and ...
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The Mohammadabad deposit is located in vicinity of Delijan in central province and in terms of structural zones of Iran,in the Uremia dokhtar zone. Stratabound Fe-Ce mineralization in brecciated, vein, massive, layered and laminar forms, consists ore minerals such as hematite, pyrite, chalcopyrite and magnetite ,is seen in lower Eocene volcano sedimentary unites. Amounts , ratios and diagrams of trace elements and rare earth elements show hydrothermal mineralization with the predominance of magmatic fluids. The values of δ34SCDT of sulfide minerals (-2.76 to1.51 ‰) and suggest the magmatic source for sulfur or mineralizing fluid with magmatic sulfur. The values of δ13C (mean 3.61 ‰), δ18O(mean12.946‰) related diagrams show a magmatic source for carbon, hydrothermal genesis for calcite and a mineralizing fluid dominantly magmatic source. above evidences,وthe location of the region in tensile tectonic regime in western edge position of uremia dokhtar magmatic arc during the Eocene and presence of magmatic mass in the depths of the region with high potential for iron and copper mineralization , sulfur supply ,also has played role of a heat engine to circulating and transfer of mineralizing fluids to the sea bed. Offers exhalative-hydrothermal processes model for deposit genesis in Eocene volcano sedimentary units
