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.
