【摘要】 晚印支期花岗岩岩石类型主要为一套含角闪石黑云母二长花岗岩及含黑云母正长花岗岩,岩石中暗色闪长质岩包体发育较普遍,富含角闪石及镁质黑云母,副矿物以榍石、磁铁矿、磷灰石常见,Al2O3/(Na2O+K2O+CaO)<1.1,显示出I型花岗岩特征。利用岩石矿物组合、岩石化学特征判别其产于碰撞后构造环境,认为造山后伸展体制是这期花岗岩形成的重要原因。岩石(87Sr/86Sr)i及δEu值反映其源区为壳幔过渡区,氧同位素(1δ8O)测定值在5.5‰-10‰之间,具壳幔混源的特点,表明岩石来源于下地壳或壳幔过渡部分,与下地壳的部分熔融或壳幔过渡区部分熔融作用有关。更多还原

【Abstract】 Main types of the late Indosinian granites in the Yichun area are amphibole-biotite-bearing adamellite,biotite-bearing syenogranite.The melanocratic diorite enclaves are development in granites.Granites are rich in amphibole and magnesian biotite,accessory minerals are titanite,magnetite and apatite.Al2O3/(Na2O+K2O+CaO) values are less than 1.1.These show that the granites have characteristics of I-type granite.The mineral association and petrochemistry indicate that the granite was generated in the post-collision,and the post-orogeny extensional system is the important reason of its generation.The high(87Sr/86Sr)i values and δEu values show that the source area is the transitional parts of the crust and mantle.δ18O values range from 5.5‰ to 10‰, showing that they have the characteristics of crust and mantle mixing origin.The source of rocks was the lower crust or the transitional parts of the crust and mantle,and might get in touch with partial melting of the lower crust or the transitional parts of the crust and mantle.更多还原