Objective The large−scale Huangjindong gold deposit is one representative gold deposit in the Northeastern Hunan ore cluster, Jiangnan terrain, and it has gold resources about 80 tons, and the average grade is about 5 g/t. The orebodies mainly occur in the slates of the Neoproterozoic Lengjiaxi Group.

Methods In order to reveal the processes of large−scale gold enrichment, the trace element composition of gold−bearing sulfides and the occurrence mechanisms of invisible gold in the Huangjindong gold deposit are researched in this study. Detailed field geological investigation, texture revealed by electron probe microstructure and trace elements determined by laser denudation plasma mass spectrometer (LA−ICP−MS) were carried out in this work. The results show that pyrite and arsenopyrite have homogeneous texture, and the zone texture is lacking. LA−ICP−MS trace element analyses result show that the invisible Au content in pyrite ranges from 3.1×10⁻⁶ to 111.5×10⁻⁶, with an average of 31.9×10⁻⁶. The invisible Au content in arsenopyrite ranges from 0.6×10⁻⁶ to 279.4×10⁻⁶, with an average of 67.2×10⁻⁶. The invisible gold content in pyrite lies below the saturation line, suggesting that the invisible gold is mainly lattice gold. There are a few gold nanoparticles revealed by the peak signals. By comparing the published trace element data of pyrite and arsenopyrite from the Yanshanian large gold deposits from the Jiangnan terrain, we discover that contents of Sb, Cu, Se and Te are of certain differences among these deposits with different elemental assemblage, indicating that, to some extent, trace element composition of gold−bearing sulfide could provide important information on the ore−forming processes differences.