Petrogenesis and metallogenic implications of the Late Jurassic Dagayin pluton, southern Great Xing'an Range, northeast China: Integrated geochronological, petrological, and geochemical constraints

The study presents new zircon laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) U-Pb ages and in situ zircon Hf isotopic data for representative Dagayin granites in the southern Great Xing'an Range (SGXR). New data provide insight into the evolution of magmatism in the SGXR. The zircon U-Pb analysis yielded 156.8 +/- 1.2 and 155.9 +/- 0.7 Ma for the Dagayin granites. The granites contain 77.0-74.2 wt% SiO2, 13.2-11.4 wt% Al2O3, 3.9-2.9 wt% Na2O, 4.6-3.5 wt% K2O, and 0.5-0.1 wt% MgO, are metaluminous to peraluminous and high-K calc-alkaline rocks. The granites also enriched the large ion lithophile elements (LILE; e.g., Rb, Th, and U) and depleted in Ba, Sr, P, Ti, and Nb. Zircons grains within the Dagayin granite yield sHf(t) values of 7.5 to 9.4 and TDM2 model ages of 728-607 Ma. Geochemical characteristics and zircon Hf isotopic data indicate the magmas were generated from the partial melting of juvenile crustal material originating from the depleted mantle. The Dagayin granites are compositionally similar to abundant mineralization-related granitoids in the SGXR, suggesting the Dagayin pluton may be prospective for exploring Pb-Zn-Ag or Mo mineralization. In the Late Jurassic to Early Cretaceous, the SGXR was under an intracontinental extensional environment, relating to the superimposed subduction of the Mongol-Okhotsk plate beneath the Central Mongolia Massif, and the Paleo-Pacific oceanic beneath the Central Mongolia Massif.