Abstract:
Objective The Mangyahedong gold deposit, located in the central Qimantage area of the East Kunlun orogen, is the first discovered orogenic gold deposit with significant exploration potential in the Qimantage region in recent years. The ore bodies are hosted in the volcanic rock series of the Qimantage Group and controlled by NW−trending tectonic fracture zones. However, insufficient research on the genesis of the deposit has hindered further exploration.
Methods This study conducted systematic microscopic identification, TIMA mineral quantitative analysis, and LA−ICP−MS trace element analysis of pyrite from different mineralization stages. LA−ICP−MS U−Pb dating was performed on hydrothermal apatite associated with main−stage pyrite to constrain the metallogenic timing and discuss the ore−forming mechanisms.
Results ① Three mineralization stages were identified: sericitization (Stage I), carbonate−chlorite−sulfide−native gold (Stage II), and late−stage calcite−pyrite vein formation (Stage III). Electron microprobe analysis and BSE imaging revealed that, in addition to native gold, early−stage As−rich pyrite cores contain relatively higher Au concentrations (0.02%–0.06%, n=8), while pyrite rims are nearly Au−free. Main−stage pyrite exhibits As−poor cores and As−, Au−, Co−enriched intermediate rims. ② LA−ICP−MS U−Pb dating of hydrothermal apatite from gold ore yielded a lower intercept age of 406 ± 13 Ma (corrected using 207Pb).
Conclusions The Mangyahedong gold deposit is classified as an orogenic gold deposit, with mineralization linked to regional metamorphism−deformation processes. The ore−forming materials were derived from the volcanic rock series of the Qimantage Group.
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