Geochronological and geochemical constraints on the ore-related granites in Huanggang deposit, Southern Great Xing’an Range, NE China and its tectonic significance

Huanggang skarn Fe-Sn deposit is located in the main ridge Sn-polymetallic metallogenic sub-belt of the Southern Great Xing’an Range. A combination of zircon U-Pb age, geochemistry and Hf isotopic composition are reported for the orerelated granite (K-feldspar granite) of the Huanggang deposit to constrain its petrogenesis and tectonic setting. LA-ICP-MS U-Pb Zircon dating results indicate that the K-feldspar granite was intruded at 145.3 ± 1.6Ma. The K-feldspar granites belong to high-K calc-alkaline and shoshonite series, mainly peraluminous. These rocks have a negative slope from La to Lu with strongly negative Eu anomalies, they demonstrate negative Ba, Sr P, Ti and Nb spikes and positive Th, U, Nd spikes on the normalized incompatible element diagrams. The regional geological setting together with the geochemistry of the K-feldspar granite indicates that it is formed in a post-orogenic setting. The zircon Hf isotopic compositions (ɛHf(t): +5.2 to +6.6, 176Hf/177Hf: 0.282837–0.282876) indicate both juvenile crust sources that originated from depleted mantle and some ancient continental crust sources contributed to its origin, and there is a significant addition of juvenile crust under the Southern Great Xing’an Range during the time from Paleo-Neoproterozoic to Phanerozoic.