The Hekoulinchang tin polymetallic deposit in Baoqing County of Heilongjiang Province is the first one discovered in the eastern part of the Northeast China. Tectonically, this deposit is located in Wandashan Terrane of eastern Xing'an-Mongolian Orogenic Belt. Its average grades of tin, silver, lead and zinc are 0.27%, 122.89g/t, 0.84% and 1.43%, respectively. This deposit is a medium-sized tin-silver deposit, and small-sized lead-zinc deposit. The thin-vein and stockwork tin polymetallic ore bodies are dominantly hosted within the granite porphyry body and its contact zone with the Upper Triassic Dajiahe Formation. According to the detailed field geological survey and data analysis, the ore-hosting granite porphyry should be the metallogenic intrusion. LA-ICP-MS zircon U-Pb dating of the granite porphyry yields an age of 118.0 +/- 1.1Ma, indicating that the intrusion emplaced at late Early Cretaceous. Its petro-geochemical characteristics show that the granite porphyry belongs to I-type granite and high-medium-K calc-alkaline series, characterized by high contents of SiO2 and K2O, low contents of Fe2O3T, MgO, CaO, and transition elements. The zircon Hf isotope compositions of the granite porphyry samples indicate that the zircon has positive epsilon(Hf)(t) values ( +3.4 similar to +7.4), and the two-stage Hf model age (t(DM2)) of 701 similar to 956Ma. The whole-rock lead isotope in granite porphyry has the characteristics of those in orogenic belt and subduction zone, as Pb-206/Pb-204 = 18.414 similar to 18.460, Pb-207/Pb-204 = 15.591 similar to 15.596, Pb-208/Pb-204 = 38.470 similar to 38.761. The initial Sr value (Sr-87/Sr-86)i of the granite porphyry is 0.708136 similar to 0.708331, and the value of epsilon(Nd)(t) is -2.0 similar to -3.0. Due to studies on the petro-geochemistry and Sr-Nd-Pb-Hf isotopes, it can be concluded that the original magma of the Hekoulinchang granite porphyry was mainly derived from partial melting of the basic juvenile lower crustal material and mixed with upper sedimentary materials in a subduction zone. Based on isotope dating and geochemical data in this paper, as well as knowledge of the regional tectonic evolution, it can be concluded that both the Hekoulinchang granite porphyry and associated tin polymetallic mineralization are closely related to the subduction of the Paleo-Pacific Plate to the Eurasian Plate.
