Identification and Geological Significance of Early Jurassic Adakitic Volcanic Rocks in Xintaimen Area, Western Liaoning

The Western Liaoning area, where a large number of Jurassic-Cretaceous volcanic rocks are exposed, is one the typical areas for studying Mesozoic Paleo-Pacific and Mongolia-Okhotsk subduction process, lithospheric destruction North China Craton. identification investigation Early Jurassic adakitic in Xintaimen area particular significance exploring magma source its composition evolution, tracking crust-mantle interaction, revealing craton oceanic plates. Detailed petrography, zircon U–Pb dating, geochemistry, Hf isotope studies indicate that intermediate-acidic mainly composed trachydacites few rhyolites with formation ages 178.6–181.9 Ma. Geochemical characteristics show they have high content SiO2, MgO, Al2O3, total-alkali, high-K calc-alkaline series. They also enrichment light rare earth elements (LREEs) ion lithophile (LILEs), depletion heavy (HREEs) field strength (HFSEs), Sr low Y Yb, suggesting were derived from partial melting lower crust. ?Hf(t) values dated zircons two-stage model (TDM2) vary ?11.6 to ?7.4 1692 1958 Ma, respectively. During Jurassic, study was under long-range tectonic effects closure Ocean plate, which caused basaltic invade crust mantle-derived separated crystallized while heating Proterozoic crust, part thickened melted form these rocks.