(1) The oldest exposed strata belong to the Neoproterozoic Xiuning Formation, which is composed of tuffaceous sandstone; (2) The overlying Cambrian sequence comprises, in ascending order: the Yangliugang Formation (argillaceous limestone), the Huayansi Formation (banded micritic limestone), and the Xiyangshan Formation (argillaceous limestone intercalated with limestone lenses); (3) The Upper Ordovician is represented by the Changwu and Wenchang Formations, which are characterized by rhythmic interbeds of siltstone, mudstone, and fine-grained sandstone. These units are in fault contact with the underlying Cambrian rocks; (4) Silurian strata are widely distributed and form a thick siliciclastic succession. From bottom to top, they include: the Lower Silurian Xiaxiang and Heliuxi Formations, the middle-lower Silurian Kangshan Formation, and the Middle Silurian Tangjiawu Formation. These are dominated by sandstone, siltstone, and mudstone, with the Heliuxi and Kangshan Formations recognized as important ore-bearing sequences; (5) The Upper Devonian includes the Xihu and Zhuzangwu Formations, which are composed of thick-bedded quartz sandstone and conglomerate. The Carboniferous succession consists of the Yejiatang Formation (quartz sandstone), the Huanglong Formation (dolomitic limestone), and the Chuanshan Formation (cryptocrystalline limestone). The Permian is represented by micritic limestone of the Qixia Formation; (6) finally, the Lower Cretaceous is represented by rhyolitic crystal-vitric tuff of the Huangjiang Formation, which unconformably overlies the Cambrian strata.
Igneous activity in the area is predominantly of the late Yanshanian and encompasses granite porphyry, granite, quartz felsite porphyry, and felsite porphyry. These intrusions form a coeval magmatic system that is genetically related to the mineralization. The No. 1 orebody, accounting for 82.38 % of the deposit’s total reserves, is located on the northwestern limb of the Yinkeng-Danzhuwu anticline. It occurs as veins hosted by Ordovician and Silurian strata and is structurally controlled by NE-trending faults. The orebody generally has a strike of 50° and dips northeast at 70°-80°. In contrast, the No. 2 orebody is situated within the anticline core but cannot be studied in detail because it is covered by residential facilities. Therefore, this study focuses solely on the No. 1 ore belt. Three mineralization stages of the Yinkeng Pb-Zn-Ag deposit are identified. The Yinkeng deposit is genetically classified as a magmatic-hydrothermal vein type deposit, and its ore-forming fluids are characterized by high temperature and reducing conditions.

Other Regions, Features and Areas containing this locality

References