Economic Geology
shirin fatahi; Ahmad Jahangiri; Farhad Maleckqasemi; seyedhasan tabatabaei
Abstract
Abstract Qezelbalaq Arsenic ore deposite is located in Hashtrud, 120 km from southeast of Tabriz. In this district effect of dacitic Sahand domes on sandy limestones and Qom formation sandstone with Oligomiocene age and pyroclacitic units with Miocene age leads to formation of various types of alteration ...
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Abstract Qezelbalaq Arsenic ore deposite is located in Hashtrud, 120 km from southeast of Tabriz. In this district effect of dacitic Sahand domes on sandy limestones and Qom formation sandstone with Oligomiocene age and pyroclacitic units with Miocene age leads to formation of various types of alteration such as Silicic, phyllic, intermediate argillic, advanced argillic and dolomitization. It seems that Arsenic mineralization has occurred in two main step: 1) Pyrite± Chalcopyrite± Arsenopyrite that are consistent with phyllic zone. Fluide responsible mineralization have high temperature (nearly 250 centigrade degree) and fs2 between 10-15 to 10-20 and 2) Pyrite± Native arsenic± Realgar± Orpiment± Galena± Stibnite wich are consist with intermediate argillic and advanced argillic zones. Hydrothermal fluid in this stage has lower temperature (nearly between 180 to 210 centigrade degree) with fs2 between 10-7.8 to 10-13. These assemblage are associated with hematite, diaspore, kaolinite, alunite and arsenolite. Average of arsenic grade in phylilc zone is 655 ppm and in argillic zone is 11930 ppm. Mass change calculation indicate enrichment in many metals such as As, Sb, Hg, Ag and Au. According to geochemical studies, As, Hg and Sb are pathfinder for probebly Porphyry copper mineralization and gold in study area.
