Spatial- temporal relationship of mineralization and magmatism in the Mazraeh polymetallic deposit (north of Ahar, Eastern Azarbaijan province)

Abstract

The Sheyvar-Dagh batholith, one of the most important intrusive bodies in northwest Iran, intruded the Upper Cretaceous and the Eocene volcano-sedimentary sequences and associated with some Cu- Fe (±W±Au) mineralization. The Sheyvar-Dagh batholith consists of different phases of magmatism (33- 10Ma) with different compositions and geochemical features. The oldest phases (Oligocene) with granite, granodiorite, syenite, and gabbro composition are dominated by plagioclase and alkali- feldspar as phenocrysts which is indicative of low water content in their parent magma, therefore, they are not associated with any mineralization. While, the younger magmatic phases (Miocene) with overall quartz monzonitic composition and amphibole- biotite phenocrysts show adakitic signature with more water content (>4% H2O). The younger magmatism shows a close temporal-spatial relationship with a variety of ore mineralization. So, this can be used as an exploration key in the Sheyvar-Dagh region. In the Mazraeh area, mineralization has occurred in two forms massive (skarn) and veinlet-disseminated (intrusion- related). Skarn mineralization, which mainly consists of garnet, epidote, magnetite, pyrite, and chalcopyrite, occurred in the Upper Cretaceous limestones, while veinlet-disseminated mineralization occurred in both the Miocene subvolcanic and the Oligocene coarse-grained bodies, and is associated with weak potassic and phyllic alterations.

Keywords

• : skarn
• intrusion related
• sheyvar-dagh batholith
• exploration pattern
• mazraeh mine
• arasbaran zone