Geochemistry and tectonic significance of Early Cretaceous granites in Highland 1248 of Daxing'anling

The Early Cretaceous granitic complex in Highland 1248 of Daxing''anling successively consists of in- truded granodiorite，monzonite granite and syenite granite． Through test analysis on the major，trace and rare earth elements of the intrusive complex，this study focuses on the source characteristics and tectonic environ- ment of the original magma of intrusive complex． The results show that the intrusive rocks in Highland 1248 are meta-aluminous-peraluminous rocks in calc-alkaline series with homologous characteristics in δEu negative anomalies; the complex is enriched in LILE (Ｒb，Cs and K) and depleted in HFSE (lanthanide，Sc，Y，U， Nb and Ta)，displaying the geochemical characteristics of I-type granites in active continental-margin subduc- tion zones． The complex also has the characteristics of granites after the collision of plate with rich aluminum and high potassium，but significantly depleted Nb，Ta，Ti，P and other elements，i． e． in the orogenic evolu- tionary stage． The zircon U-Pb SHＲIMP isotopic apparent age of the complex in Highland 1248 is 140． 0--141. 0 Ma，and the formation time is in Early Cretaceous．