巴音勿拉山岩体位于华北克拉通北部,白乃庙岛弧岩带南部,锆石LA-ICP-MS U-Pb定年结果及锆石特征表明其侵位时代为(410.9±1.2)Ma。岩体岩石组合为一套正长岩杂岩,富钾富碱,铝质量分数较高,属偏铝质岩石。地球化学特征表明岩浆源区为岩石圈地幔,岩浆演化过程中下地壳的同化作用显著。其形成与白乃庙岛弧岩带与华北克拉通碰撞后的伸展作用有关。
Bayinwulashan pluton was located in the north of North China Craton and the south of the Bainaimiao Arc. Zircon LA-ICP-MS U-Pb dating and the characteristic of zircons indicates that the age of pluton was (410.9 ± 1.2) Ma. Pluton is composed of complex rocks of syenite, characterized by a strong enrichment in kalium and alkali, has high content of aluminum and belong to metaluminous series. Geochemical characteristics show that magma source of pluton was the lithospheric mantle, and the assimilation of lower crust was obvious during the magma evolution process. Its formation was concerned with the extension after the collision of North China Craton and Bainaimiao Arc.