2019/04/12 by Valentín R. Troll, Franz Weis, Erik Jönsson +8 · 2 citations
Earth and Planetary Sciences · Biochemistry, Genetics and Molecular Biology · #Geological and Geochemical Analysis #Geochemistry and Elemental Analysis #Geomagnetism and Paleomagnetism Studies
paper · pdf · doi:10.1038/s41467-019-09244-4
openalex publication_date 2019/04/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
Abstract Kiruna-type apatite-iron-oxide ores are key iron sources for modern industry, yet their origin remains controversial. Diverse ore-forming processes have been discussed, comprising low-temperature hydrothermal processes versus a high-temperature origin from magma or magmatic fluids. We present an extensive set of new and combined iron and oxygen isotope data from magnetite of Kiruna-type ores from Sweden, Chile and Iran, and compare them with new global reference data from layered intrusions, active volcanic provinces, and established low-temperature and hydrothermal iron ores. We show that approximately 80% of the magnetite from the investigated Kiruna-type ores exhibit δ 56 Fe and δ 18 O ratios that overlap with the volcanic and plutonic reference materials (> 800 °C), whereas ~20%, mainly vein-hosted and disseminated magnetite, match the low-temperature reference samples (≤400 °C). Thus, Kiruna-type ores are dominantly magmatic in origin, but may contain late-stage hydrothermal magnetite populations that can locally overprint primary high-temperature magmatic signatures.