The gold-telluride connection: Evidence for multiple fluid pulses in the Jinqingding telluride-rich gold deposit of Jiaodong Peninsula, Eastern China

The mechanism of gold migration, enrichment, and precipitation in forming world-class gold deposits has been a topic of wide interest, particularly where these deposits are abundant in tellurides. The Jiaodong Peninsula in eastern China hosts some of the world-class gold deposits among which the Jinqingding deposit is one of the best examples with substantial telluride mineralization and thus provides opportunity to investigate the genetic connection between tellurium and gold mineralization. The orebody in this deposit is hosted in the NE-NNE-trending Jiangjunshi-Quhezhuang fault with the Jurassic Kunyushan granitic pluton as wall rock. The deposit involved three mineralization stages as inferred from assemblages and crosscutting relationships between veins. These stages are: (I) pre-ore gold-poor quartz-pyrite veins, (II) main ore auriferous quartz-pyrite-Te/Bi-minerals ± sphalerite ± chalcopyrite ± barite ± marcasite veins, and (III) post-ore quartz-calcite veins. We present here the textural, isotopic, and geochemical variations of different stages/generations of pyrite based on scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), electron probe microanalysis (EPMA), and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS).Pyrite in the Jinqingding deposit displays distinct characteristics. Py1a shows a porous and dissolution-reprecipitation texture in the core, whereas Py1b exhibits a smooth and flat rim. Geochemical analysis reveals contrasting elemental compositions, with Py1a characterized by low Au (avg. 0.14 ppm), As (avg. 15.57 ppm), Ag (avg. 17.71 ppm), and Te (avg. 19.22 ppm) contents, but elevated Co (avg. 1068.10 ppm) and Ni (224.12 ppm) concentrations, and variable sulfur isotopic composition (δ³⁴S_V-CDT = 9.54‰-12.12‰). Conversely, Py1b displays increased concentrations of these elements and a more concentrated δ³⁴S_V-CDT value (11.99‰-12.23‰), possibly associated with weak coupled dissolution-reprecipitation (CDR) processes. In Stage II, pyrite can be further categorized into two generations: the porous core (Py2a) and the smooth periphery (Py2b). Notably, Stage II exhibits increased contents of Au (Py2a: avg. 0.47 ppm; Py2b: avg. 5.57 ppm), As (Py2a: avg. 1265.20 ppm; Py2b: 1049.46 ppm), Ag (Py2a: avg. 5.43 ppm; Py2b: avg. 65.23), and Te (Py2a: avg. 21.47 ppm; Py2b: avg. 51.66 ppm), δ³⁴S_V-CDT value exhibits minor changes (Py2a: 11.48‰-13.05‰; Py2b: 11.79‰-12.80‰). These changes potentially indicate the involvement of a fluid pulse characterized by low fO₂: -34.9 to -30.2, medium fTe₂: -14.7 to -10.9 and fS₂: -11.4 to -6.9. Despite the dissolution-reprecipitation textures present in the ores, gold did not undergo remobilization, except for a possible weak contribution in Stage II. The presence of abundant Bi/Te-minerals underscores the significant role of low-melting point chalcophile elements in gold migration and enrichment. By compiling and analyzing sulfur isotopic composition of gold deposits across the entire Jiaodong Peninsula, which shows the reduction of marine sulfates as a crucial mechanism for sulfur enrichment. We conclude that the Jinqingding gold deposit, characterized by abundant tellurium, along with episodic pulses of ore-forming fluids, and exhibit subtle distinctions compared to other gold deposits within the Jiaodong Peninsula.