China Geology (Jan 2022)
Geochronology and geochemistry of the Hekoulinchang Sn-Pb-Zn-Ag polymetallic deposit (73240 t) in Heilongjiang Province, China
Abstract
The Hekoulinchang Sn-Pb-Zn-Ag polymetallic deposit (20000 t Sn at 0.27%, 236 t Ag at 122.89 g/t, 15000 t Pb at 0.84%, and 38000 t Zn at 1.43%) is located in the Wandashan Terrane of the easternmost segment of the Central Asian Orogenic Belt. The timing of Sn-Pb-Zn-Ag polymetallic mineralization remains unclear due to a lack of precise isotope dating directly conducted on ore minerals. The authors herein report that the LA-ICP-MS U-Pb ages of cassiterite and zircon from the granite porphyry in the Hekoulinchang Sn-Pb-Zn-Ag polymetallic deposit are 101.4±7.9 Ma and 115.4±1.0 Ma, respectively, indicating that Sn mineralization and magmatism occurred during the Early Cretaceous. The granite porphyry belongs to the subalkaline series peraluminous I-type granites that are depleted in Nb, Ta, and Ti and enriched in Rb, Th, U, and Pb. The εHf(t) values of the granite porphyry range from 0.9 to 7.4, with an average of about 5.6 and two-stage model ages (TDM2) of 705–1116 Ma, with an average age of 819 Ma. The εNd(t) values of the apatites are –1.60–0.45, with an average of –0.9, and two-stage model ages (TDM2) of 872–1040 Ma, with an average age of 983 Ma. The Nd-Hf isotope data indicate that the magma may have been derived from the partial melting of juvenile crustal material.© 2022 China Geology Editorial Office.
