Geology and geochemistry of the high-grade Zankan magnetite ore, Western Kunlun Mountains, NW China

• DOI: 10.1016/j.oregeorev.2022.105129
• Publication Date: 2022-09-26T16:08:54Z
• Authors: Zhiquan Li; Yongzhang Zhou; Pengpeng Yu; Lianchang Zhang; Wei Wei; Yuhao Li; Kurt O. Konhauser; Leslie J. Robbins
• Keywords: Isotope Geochemistry; Ore genesis; Iron ore; Banded iron formation; Dacite

Over the past decade, several magnetite-rich iron deposits have been discovered in Taxkorgan region of western Kunlun Mountains northwestern China. These include Zankan, Jiertieke, Laobing, Yelike, and Taaxi deposits. Prospective ore reserves are estimated at over 1 billion tons, with an average magnetite grade 28% (Feng et al., 2018). The largest deposits, Zankan Iron Deposit (ZID), is to contain 628 million tons ore, least 10% ores being high-grade (TFe > 50 wt%). However, geological processes by which ZID were formed remains poorly constrained. In this study, we combine whole rock geochemistry data, oxygen sulfur stable isotopes, uranium-lead hafnium isotopes from zircons elucidate plausible mechanisms underpinning formation ores. Based on mineralogy, define two types. Type essentially comprised quartz magnetite, interlayered schist, it retains sedimentary fabrics precursor iron-rich sediments (IF). 2 intrusion a dacite-porphyry into IF led remobilization recrystallization as manifest magnetite-ferro actinolite veining. Rare earth element (REE) characteristics differs those IF, chondrite normalized REE patterns showing enrichment LREE significant negative europium anomalies close dacite-porphyry. isotopic composition pyrite suggests further meteoric influence silica driven leaching elsewhere sequence. Circulation forming fluid attributable development faults fracture zones that resulted Laser ablation analyses yield groups ages 551.25 ± 3.32 Ma 497.82 3.81 Ma, representing captured detrital intrusive age dacite porphyry, respectively. Given intimate relationship between T2 suggest after Ma. Collectively our field observations geochemical data reveal detailed alteration ZID, identifying distinctive features may help guide future exploration for additional region.