Objective The Zhangjiapingzi gold deposit in Mianning, Sichuan, is one of the important gold deposits on the western margin of the Yangtze Craton. Owing to the inherent complexity of mineralization itself and inadequate research coverage in local regions, there remain several key issues that require in−depth investigation. These include the unclear occurrence state of gold, the ambiguous chemical composition of gold−bearing minerals, as well as considerable controversies regarding the genetic mechanism of the deposit. This study focuses on the Zhangjiapingzi gold deposit to address the above problems.

Methods Through field geological surveys and technical means including optical microscopy, electron probe microanalysis (EPMA), and laser ablation−inductively coupled plasma−mass spectrometry (LA−ICP−MS), research on the Zhangjiapingzi gold deposit was carried out. Results This study elaborates on the geological characteristics of the deposit, the chemical compositions of gold and gold−bearing minerals, and their geological significance. The results show that gold minerals in the Zhangjiapingzi gold deposit mainly occur as native gold, predominantly as Inclusion gold within pyrite, with partial invisible gold distributed in minerals such as pyrite. Specifically, pyrite has a sulfur content ranging from 52.254% to 54.000% (average: 53.043%) and iron content from 43.813% to 47.526% (average: 45.985%). Gold minerals have an Au content of 92.108%~94.343% (average: 93.588%) and Ag content of 6.581%–6.852% (average: 6.756%), with a gold fineness ranging from 931 to 934 (average: 933). Additionally, the results of LA−ICP−MS analysis on 40 pyrite grains from this deposit show that among the valid analysis spots, a total of 28 have Co/Ni ratios < 1, while only 2 have Co/Ni ratios > 1.

Conclusions Integrating the results of this study and previous research, it is concluded that the Zhangjiapingzi gold deposit should be classified as an orogenic gold deposit.