Objective The Qianchuiliu gold deposit is a newly discovered large−scale altered rock−type gold deposit in the northeastern margin of the Jiaolai Basin. Post−mineralization intermediate−mafic dikes (lamprophyre, diabase, and diorite porphyry) are widely developed in the mining area. Their formation age, petrogenesis, and relationship with gold mineralization remain unclear. Studying these dikes can provide new evidence for understanding the coupling between regional tectonic−magmatic evolution and mineralization processes.

Methods Intermediate−mafic dikes (lamprophyre, diabase, and diorite porphyry) cutting through mineralized alteration zones were collected from surface and subsurface in the mining area. Systematic petrographic, whole−rock geochemical, and zircon U−Pb geochronological studies were conducted to analyze their geochemical characteristics, magma source, and formation age.

Results The dikes exhibit alkaline, high−K, and low−Ti characteristics, with enrichment in large−ion lithophile elements (Ba, Th, U) and light rare earth elements (LREE), and depletion in high−field−strength elements (Nb, Ta, Zr) and heavy rare earth elements (HREE). These geochemical features classify them as shoshonitic to high−K calc−alkaline series, indicating a subduction−related tectonic setting. Geochemical and isotopic compositions, combined with zircon U−Pb age spectra, reveal that the dikes were derived predominantly from an enriched mantle source, with incorporation of Paleoproterozoic to Triassic crustal materials from the North China Craton and Sulu orogenic belt during magma emplacement, resulting in varying degrees of crustal contamination. The youngest weighted mean zircon U−Pb age of 117.5±1.8 Ma from the three dike types represents their final crystallization age. Together with their crosscutting relationship with mineralized alteration zones, this constrains the main gold mineralization at Qianchuiliu to have terminated by the Early Cretaceous (≥117.5 Ma), consistent with the previously defined lower limit of mineralization age in this region.

Conclusions The formation of the Qianchuiliu gold deposit is genetically associated with large−scale Yanshanian tectonic−magmatic activities in eastern North China. The emplacement of intermediate−mafic dikes (~117.5 Ma) marks the termination of regional gold mineralization, demonstrating significant contributions from crust−mantle interactions under the Pacific Plate subduction setting. These findings provide new geological evidence for understanding the tectonic−magmatic−mineralization coupling during the Yanshanian period in eastern China.