Genesis and Geological Significance of Magnetite and Ilvaite in the Arqale Pb-Zn-Cu Deposit, Western Tianshan, Xinjiang

The Arqale lead-zinc-copper deposit is located on the southwestern margin of the Yishijilik metallogenic belt in the Western Tianshan, Xinjiang. The ore bodies occur as stratiform and stratoid shapes within the limestone of the Lower Carboniferous Akshak Formation. This study conducted systematic petrographic and mineralogical identification and electron microprobe composition analysis on magnetite and ilvaite to determine the mineral formation genesis, ore-forming physicochemical conditions, deposit genesis, and prospecting direction. Magnetite in the ore occurs as granular or radial aggregates, with low Ti and V contents and high Al and Mn contents, indicating a formation temperature of 200-300°C. Ilvaite in the ore shows low Fe²⁺ content but high Mn²⁺ content, characteristic of manganiferous ilvaite, and formed in a relatively oxidized ore-forming environment. The elemental compositions of both magnetite and ilvaite are similar to those of typical skarn deposits. Combined with the widespread development of skarn minerals such as garnet-hedenbergite-actinolite-ilvaite, this study concludes that Arqale is a distal skarn-type Pb-Zn-Cu deposit closely related to deep concealed magmatism, and speculates that skarn contact zones and iron-copper mineralization may exist at depth.