Genesis of the Xiaotazigou gold deposit in the northern margin of the north China craton: constraints from sulfur isotopes, rare earth elements, and trace elements

The Xiaotazigou gold deposit is located in the eastern section of the Chifeng–Chaoyang gold metallogenic belt on the northern margin of the North China Craton. In this study, rare earth and trace element compositions of ores and host rocks, together with sulfur isotope data, were applied to constrain the geochemical characteristics of ore-forming fluids and the sources of ore-forming materials. The results show that the ores are enriched in light rare earth elements (LREE) and display negative Eu anomalies, with Hf/Sm, Nb/La, and Th/La ratios all 1, suggesting a magmatic–hydrothermal origin. Variations in Y/Ho and Zr/Hf ratios, coupled with relatively stable Nb/Ta ratios, imply that the hydrothermal system was influenced by fluid mixing with meteoric water during evolution. The δ 34 S values of pyrite (2.67‰–3.70‰, avg. 3.14‰) are close to mantle-derived sulfur, indicating a dominant mantle source for the ore-forming materials. Moreover, similar rare earth element distribution patterns and trace element geochemical behaviors between ores, monzogranite, and gneiss suggest that the granitoids and gneiss also contributed essential material to the mineralization. Integrating geochemical data and regional tectonic setting, the Xiaotazigou gold deposit is classified as an orogenic gold deposit formed in an intracontinental orogenic regime after the collision between the North China Craton and the Siberian Plate. This study provides new constraints on ore genesis and contributes to understanding gold metallogeny in the northern margin of the North China Craton.