Mineralization, structure and texture and genesis of Halab gold occurrence, southwest of Dandy, Zanjan Province

Mineralization in the Halab occurrence occurs as Au-bearing silicified-sulfidic zone within Precambrian mafic schist sequence. Ore minerals include arsenopyrite, sphalerite, pyrite, chalcopyrite, pyrrhotite and gold, and quartz, actinolite, clinopyroxene, and chlorite are present as gangue minerals at Halab. The ore minerals show banded, laminated, disseminated, veinlet, brecciated, vug infill, colloform, replacement, and relict textures. Alteration are consist of actinolitization, silicification, and chloritization. Four stages of mineralization can be distinguished at Halab. Gold mineralization is related to hydrothermal stage (stage 3) accompanied with arsenopyrite. Field and analytical results reveal that primary mineralization at Halab occurs as sub-economic stratiform and startabound, laminated and disseminated Zn‒Cu mineralization coeval with the deposition of the volcano-sedimentary units which that overprinted during later metamorphic-deformation process. This primary Zn‒Cu mineralization is comparable with metamorphosed and deformed laminated and disseminated parts of the Besshi type massive sulfide deposits. Gold mineralization is related to late hydrothermal phase which is thought to be result of Miocene magmatism in the Takab–Takht-e-Soleyman–Angouran zone. Investigation of alteration zones within Precambrian metamorphosed units which have spatial relationship with Miocene magmatism, is, therefore, of major importance in exploration of this type of gold mineralization at the Takab–Takht-e-Soleyman–Angouran zone.