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Using GIS-based multi-criteria decision-making techniques, i.e. mineral prospectivity mapping (MPM), specific spatial problems can be solved by combining information from different sources. Orogenic gold mineralisation shows weak exploration signals on the surface that can challenge exploration geologists. This study investigates the ability of a MPM method called evidential belief functions (EBFs) to identify a local orogenic gold mineralisation in the Godaesorkh gold deposit, north of Sanandaj-Sirjan Zone (Central Iran). Several evidential layers such as geological, structural, geophysical, remote sensing, and geochemical layers were generated by applying various processing methods. These layers are integrated to attain a MPM by applying the EBFs based on Dempster-Shafer's rules. Precise selection of evidential layers and higher number of known mineral occurrences may lead to a higher degree of belief in the mineral prospectivity map. Accordingly, high probability values were correlated with the gold mineralisation in the study area, and three separate areas were identified as promising with N40E and N15W trends. It is concluded that the orogenic gold mineralisation occurred in shear zones, which is mainly controlled by tectonic structures. Consequently, analysing these structures can be considered as a key feature for identifying potential orogenic gold mineralisation zones in the study area. [ABSTRACT FROM AUTHOR]

The Baghu gold deposit, hosted by a granitoid stock as well as volcanic rocks, is located in Northern Iran. The igneous rocks consist of granodiorite and granite as well as volcanic rocks, such as basaltic andesite and andesite, which are cut by dioritic dykes. The igneous rocks have metaluminous, high K calc‐alkaline, and island‐arc signatures, characterized by enrichment in large‐ion lithophile elements (LILEs) and depletion in high‐field‐strength elements (HFSEs). Zircon separates yield U–Pb ages of 47, 43, and 38 Ma for the volcanics, granitoid rocks, and dyke, respectively, indicating that the magmatism associated with gold–copper mineralization occurred during the Eocene. The low Ba/Th, Th/Nb, Ba/La, and Th/Yb ratios in igneous rocks indicate that their mantle source was not likely modified by subduction activity. A comparison of La/Sm against La (ppm), similar Th/Nb and Th/Yb, and average (La/Yb)n ratios to the crust and lower continental crust (LCC) suggests that the magmatism in the Baghu was likely associated with partial melting of juvenile lower crust, induced by north‐westward subduction of the Neo‐Tethys oceanic lithosphere in an extensional setting. [ABSTRACT FROM AUTHOR]

The Zinvinjian polymetallic deposit occurs as veins controlled by a NW–SE trending–structure within the Cretaceous metamorphosed limestone and dolomite, schist, and metavolcanic rocks, northwest of Iran. The retrograde greenschist facies metamorphism was accompanied by large–scale transpressional faulting, crack–seal veins, infiltration of large volumes of hydrous fluid with high X CO 2 , and is largely overlapped by the main hydrothermal events. The metamorphism has resulted in two stages of mineralization in the Zinvinjian deposit. These are early–stage polymetallic sulfides–quartz and late–stage pyrite–quartz veins. The early–stage veins filled fractures and are undeformed, suggesting a tensional shear setting. The late–stage veins are also mainly open–space fissure–fillings that cut or replace earlier veins. Three types of fluid inclusions (FIs), including aqueous (type–I), mixed carbonic–aqueous (type–II), and carbonic (type–III), were identified in ore–related quartz veins. The early–stage quartz contained all three types of primary FIs homogenized at temperatures of range 197–300 °C and salinities of 2.5–15.2 wt% NaCl equivalent. In contrast, the late–stage quartz veins contained only type–I FIs with homogenization temperatures ranging between 192 and 210 °C, and salinities of 0.2–2.7 wt% NaCl equivalent. This indicates that the metallogenic system evolved from a carbonic–rich, metamorphic fluid to a carbonic–poor, one through input of meteoric fluids. All three types of FIs in the early–stage minerals displayed evidence of vein formation during an episode of fluid immiscibility. Quartz δ 18 O (+ 15.3 to + 19.0‰) and sulfide δ 34 S (− 9.4 to + 11.6‰) indicate isotopic equilibrium with host metasediments (rock buffering) and a metasedimentary source of sulfur during early–stage. It is believed that ore mineralization is the result of a decrease in base–metal solubility during an episode of the fluid immiscibility. This study suggests that mineralization at the Zinvinjian deposit is metamorphogenic in style, probably related to a deep–seated orogenic system. [ABSTRACT FROM AUTHOR]

The Malayer-Esfahan Metallogenic belt (MEMB), in the southwestern Iran, contains numerous different types of the sediment-hosted Zn-Pb (±Ba±Ag), volcanic-sediment hosted Zn-Pb ± Ba, sideritic Fe-Mn-Pb (±Ba±Cu), and barite mineralizations. These deposits are hosted mostly in Jurassic shales and sandstones and in Early to Late Cretaceous carbonates and siltstones with minor volcanic rocks. In contrast to the orogenic-related Mississippi Valley type (MVT) deposits, the MEMB deposits formed in an extensional back-arc environment and are characterized by their stratabound and stratiform orebodies. In these deposits, silicification and dolomitization (± sericitization) are the main wall-rock alteration styles. The presence of primary laminated sulfides, fine-grained disseminated sphalerite and galena in association with framboidal pyrite, sedimentary structures in sulfide laminae and bands, and the association of some tuffaceous and volcanic rocks with sulfide mineralizations, along with replacement ore textures in the MEMB deposits are not compatible with orogenic-related MVT model for these mineralizations. These characteristics in the Cretaceous MEMB deposits are more compatible with a sub-marine hydrothermal system with sub-seafloor replacement mineralization (e.g., Irish type). Some deposits also share characteristics between Irish type and volcanogenic massive sulfide (VMS) deposits, called VSHMS in this paper. The main argument against the MVT model of Karimpour and Sadeghi (2018) is that this model is not acceptable for the MEMB deposits and could not explain metallogenic aspects of the Zn-Pb (±Ba±Ag) and other mineralizations in this belt. Unlabelled Image [ABSTRACT FROM AUTHOR]