Magnetite chemistry and implications for the magmatic-hydrothermal ore-forming process: An example from the Devonian Yuleken porphyry Cu system, NW China

Magnetite in the Devonian Yuleken porphyry Cu–Mo deposit located in NW China witnessed complicated magmatic-hydrothermal ore-forming processes. The magnetite grains can be divided into MagI-A (from the Beitashan Formation basalt), MagI-B (from the porphyritic syenite wall rock), MagII (from sodic-calcic alteration zone), MagIII-A (from early potassic stage with no concomitant sulfides) and MagIII-B (from late potassic alteration coexisting with...