Abstract:
The Tanchang-Xihe area represents the most important antimony (gold) ore district in the West Qinling region and even the wider northwestern China. It hosts several large antimony deposits(Yawan, Taishan and Washigou), as well as the super-large Daqiao gold deposit. Recent exploration has yielded significant advances. The newly discovered Baiyangba antimony deposit (medium-sized) is characterized by a large strike extent of ore belts, with ore bodies occurring in both pinch-out-reappearance structures and parallel fault zones. The Miaogou antimony-gold deposit (small-sized) is the first Sb-Au paragenetic deposit identified in the district, offering new exploration directions and highlighting the need to strengthen gold exploration efforts. At the Washigou antimony deposit, the ore bodies controlled by structural dilation spaces formed by faults and folds, exhibiting stable strike extensions and locally developed large cavities that host giant ore pockets. At the Caoshangou antimony deposit, significant deep exploration results reveal considerable vertical extension and pinch-out–reappearance characteristics of the ore bodies. Theoretical studies indicate that cooling is the primary mechanism for stibnite precipitation, and a shift toward neutral pH further promotes this process. Regional metallogeny is jointly controlled by multi-order structures and lithological units. The Hezuo-Tanchang-Liangdang deep fault governs the distribution of the ore district, whereas secondary faults and folds serve as the main ore-hosting structures. Argillaceous rocks act as impermeable barriers, while calcareous sandstones and limestones constitute favorable host units. A comprehensive exploration model has been established incorporating tectonic setting, ore-controlling structures, host strata, lithological associations, alteration characteristics, and geochemical anomalies. Using multi-information fusion of 1∶50000 stream sediment geochemical data, nine new exploration targets have been delineated.Overall, the ore district exhibits significant potential for Sb-Au mineralization. Further exploration efforts should be strengthened based on the metallogenic characteristics to achieve a full breakthrough.