{"title":"Mineralogy, geochemistry, and fluid inclusion studies of the Rayen Fe deposit, Iran: implications for ore genesis","authors":"Balandeh Aminzadeh","doi":"10.1007/s12517-025-12234-0","DOIUrl":null,"url":null,"abstract":"<div><p>The Rayen Fe deposit is located in the Urumieh-Dokhtar magmatic arc, a major metallogenic belt in Iran. The deposit consists of several hypogene orebodies that occur as high-grade lenticular massive magnetite bodies (up to 50 m long and 3 m wide). Magnetite geochemical compositions, microthermometric analysis of fluid inclusions, and magnetite oxygen isotope data were analyzed to constrain mineralization conditions and the genesis. The Fe mineralization is associated with the intrusion of an Eocene dioritic pluton into Cretaceous carbonate rocks. Magnetite is the most abundant ore mineral, accompanied by minor amounts of pyrite, chalcopyrite, hematite, and goethite. Pyroxene, garnet, quartz, amphibole, epidote, chlorite, and calcite are gangue minerals. The δ<sup>18</sup>O values of magnetite, ranging from + 0.15 to + 3.8‰, are consistent with precipitation from magmatic-hydrothermal fluids. The chemical signature of magnetite, including low mean concentrations of Al (0.268 wt.%), Ti (81.85 ppm), V (58.69 ppm), Cr (18.45 ppm), and Ni/Cr (mean = 3), LREE/HREE ratios (mean = 2.41), negative Ce (Ce/Ce* < 1, 0.25–0.65), and positive Eu (Eu/Eu* = 1.08–4.08) anomalies, are consistent with a magmatic-hydrothermal source for the mineralization. Results from microthermometric analyses of fluid inclusions indicate that a magmatic-meteoric mixed fluid was responsible for ore mineralization at the Rayen deposit. The tectonic setting (magmatic arc; Urumieh-Dokhtar magmatic belt), the epigenetic nature of the mineralization, textural evidence, mineral assemblages, adjacent to the dioritic pluton, microthermometric data, oxygen isotope analyses, and geochemical characteristics of magnetite indicate that the mineralization process at the Rayen Fe deposit is similar to that of skarn-type Fe deposits.</p></div>","PeriodicalId":476,"journal":{"name":"Arabian Journal of Geosciences","volume":"18 4","pages":""},"PeriodicalIF":1.8270,"publicationDate":"2025-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Arabian Journal of Geosciences","FirstCategoryId":"1085","ListUrlMain":"https://link.springer.com/article/10.1007/s12517-025-12234-0","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"Earth and Planetary Sciences","Score":null,"Total":0}
引用次数: 0
Abstract
The Rayen Fe deposit is located in the Urumieh-Dokhtar magmatic arc, a major metallogenic belt in Iran. The deposit consists of several hypogene orebodies that occur as high-grade lenticular massive magnetite bodies (up to 50 m long and 3 m wide). Magnetite geochemical compositions, microthermometric analysis of fluid inclusions, and magnetite oxygen isotope data were analyzed to constrain mineralization conditions and the genesis. The Fe mineralization is associated with the intrusion of an Eocene dioritic pluton into Cretaceous carbonate rocks. Magnetite is the most abundant ore mineral, accompanied by minor amounts of pyrite, chalcopyrite, hematite, and goethite. Pyroxene, garnet, quartz, amphibole, epidote, chlorite, and calcite are gangue minerals. The δ18O values of magnetite, ranging from + 0.15 to + 3.8‰, are consistent with precipitation from magmatic-hydrothermal fluids. The chemical signature of magnetite, including low mean concentrations of Al (0.268 wt.%), Ti (81.85 ppm), V (58.69 ppm), Cr (18.45 ppm), and Ni/Cr (mean = 3), LREE/HREE ratios (mean = 2.41), negative Ce (Ce/Ce* < 1, 0.25–0.65), and positive Eu (Eu/Eu* = 1.08–4.08) anomalies, are consistent with a magmatic-hydrothermal source for the mineralization. Results from microthermometric analyses of fluid inclusions indicate that a magmatic-meteoric mixed fluid was responsible for ore mineralization at the Rayen deposit. The tectonic setting (magmatic arc; Urumieh-Dokhtar magmatic belt), the epigenetic nature of the mineralization, textural evidence, mineral assemblages, adjacent to the dioritic pluton, microthermometric data, oxygen isotope analyses, and geochemical characteristics of magnetite indicate that the mineralization process at the Rayen Fe deposit is similar to that of skarn-type Fe deposits.
期刊介绍:
The Arabian Journal of Geosciences is the official journal of the Saudi Society for Geosciences and publishes peer-reviewed original and review articles on the entire range of Earth Science themes, focused on, but not limited to, those that have regional significance to the Middle East and the Euro-Mediterranean Zone.
Key topics therefore include; geology, hydrogeology, earth system science, petroleum sciences, geophysics, seismology and crustal structures, tectonics, sedimentology, palaeontology, metamorphic and igneous petrology, natural hazards, environmental sciences and sustainable development, geoarchaeology, geomorphology, paleo-environment studies, oceanography, atmospheric sciences, GIS and remote sensing, geodesy, mineralogy, volcanology, geochemistry and metallogenesis.