Abstract:The Bashenghe pluton in Zhalantun area of northern Daxinganling Mountains is composed of alkali-feldspar granite. The zircon LA-ICP-MS U-Pb dating yields the weighted mean age of 297.8±3.6 Ma, indicating the pluton was formed in the Early Permian. The whole rock geochemistry of 4 samples shows that the alkali-feldspar granite is characterized by rich Si, high K and rich alkali, belonging to weak peraluminous shoshonite series. The characteristics of high ∑REE, obvious negative Eu anomalies and enrichment of LILEs are properties of A-type granite. Combined with previous research results and isotopic chronology, it is concluded that the convergence of Xing'an massif and Songnen massif occurred before 298 Ma.
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Wu F Y, Yang Y H, Xie L W, et al. Hf isotopic compositions of the standard zircons and baddeleyites used in U-Pb geochronology[J]. Chemical Geology, 2006,234(1/2):105-126.