矿床地球化学国家重点实验室知识库

There are a lot of manganese (Mn) deposits and numerous mineral occurrences of this type of mineralization in Iran. The major tectonic/structural zones of Iran that host manganese deposits are: (1) Urumieh-Dokhtar magmatic assemblage (UDMA), (2) the Central Iran (CI), (3) the Sabzevar zone (SZ), (4) the Alborz magmatic belt (AMB), and (5) the Cretaceous ophiolites. These manganese deposits were formed during discrete time periods: (1) Late Neoproterozoic-Early Cambrian (Narigan and Halab deposits in the CI), (2) Jurassic (Halalan deposit in the SZ), (3) Cretaceous (Mn mineralizations in the Late Cretaceous volcano-sedimentary sequence of southwest Sabzevar basin in the SZ, Nasirabad, Abadeh-Tashk, Alashtar, Sorkhvand, Esfandagheh, Benvid, Gugher, Kamar Talar, Sardasht, and Safou, manganese deposits in the southeast of Birjand, Dehoo and north of Sabzevar deposits, which occur in the Upper Cretaceous ophiolites), and (4) Eocene-Miocene (e.g., Venarch, Jalal, Shahrestanak, Boznein, Garab, Menamin, Robat-Karim, Qaleh Mohammad Khan, Rabiei, Zarashlou, Narkan, Sarikand Jokandy, Gharaeh-Tavaragh, and Barout-Aghaji deposits in the UDMA and AMB). Magmatic arcs (intra-arc rifts and back-arc basins) are the principal plate tectonic settings for Iranian manganese deposits. All of the manganese deposits of the UDMA and AMB formed within Tertiary arc and back-arcs, respectively, that developed during subduction of the Neo-Tethyan crust beneath the Iranian plate. Intra-oceanic or continental back-arc spreading settings are recognized in the Neo-Tethys domain in Iran, and these host several manganese deposits in the SZ and ophiolites. The trace element content of all studied manganese deposits is generally low in concentrations and tends to enrichment in the assemblage of V, Cu, Pb, Zn, and As with geochemical characteristics similar to hydrothermal deposits. Rare earth element (REE) patterns of the Iranian manganese deposits support a hydrothermal origin. The main time period of formation of manganese mineralization in Iran was from Cretaceous to Miocene. The UDMA and SZ are the most favourable metallogenic provinces in Iran for manganese exploration, because these zones host the most and the largest manganese deposits, including Venarch and Shahrestanak deposits in the UDMA, and manganese mineralizations in the Late Cretaceous volcano-sedimentary sequence of the southwest Sabzevar in the SZ.