| Abstract/Notes | The Jiaodong Peninsula, as a significant gold-producing region in China, represents a frontier in international research on gold metallogenic mechanisms. The Qijiagou gold deposit, located in the eastern part of the Jiaodong Peninsula, features a spatial coexistence of native gold and Te-Bi minerals, making it an ideal subject for studying the metallogenic mechanisms of Jiaodong-type gold deposits. This study employs in-situ geochemical and isotopic analyses to constrain the ore-forming physicochemical conditions, fluid evolution processes, and the mechanisms of gold occurrence and enrichment. It can be divided into three stages: quartz-pyrite ± pyrrhotite ± marcasite ± chalcopyrite (stage I), quartz-pyrite-native gold-chalcopyrite ± sphalerite ± galena ± magnetite ± tellurobismuthite (stage II), and ore-barren quartz-calcite (stage III). The pyrites in stages I and II are characterized by porous cores (Py1a and Py2a generations) and smooth rims (Py1b and Py2b generations), with native gold inclusions primarily formed in the later-generation pyrites. This, combined with the variations in gold content across different generations, indicates that the coupled dissolution-reprecipitation (CDR) process is the main controlling factor for the mobilization, transport, and subsequent enrichment of gold during the evolution of the ore-forming fluids. The abundant Te-Bi minerals closely associated with native gold suggest a significant genetic relationship between them. The efficient extraction and transport of gold by low-melting point chalcophile elements (LMCE) melts, followed by rapid precipitation under abrupt changes in temperature, pressure, and oxygen fugacity, also contribute significantly to gold enrichment and are the primary reason for the spatial coexistence of native gold and Te-Bi minerals. Sulfur isotope compositions (δ34S = 5.57–7.65‰) suggest that sulfur was predominantly derived from the reduction of evaporites, with a possible minor contribution from magmatic sulfur. Thermodynamic modeling indicates that gold precipitation occurred under weakly acidic to neutral and moderately to strongly reducing conditions. This study reveals a multi-stage dynamic mineralization model controlled by CDR-dominated fluid evolution, LMCE melt extraction, and abrupt physicochemical changes, deepening the understanding of Jiaodong-type gold mineralization processes. |
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