河西堡花岗岩体中闪长质包体与岩浆混合作用

河西堡花岗岩体为阿拉善地块西南缘早古生代中酸性岩浆活动的产物。其中产出一些闪长岩、石英闪长岩甚至玄武岩的暗色包体，这些包体的岩相学特征暗示它们是曾经与寄主花岗岩处于同一熔融状态的基性岩浆组分的结晶产物。矿物温压计估算的结果表明，包体与寄主岩的再平衡结晶温压条件十分接近。寄主花岗岩的岩石化学、稀土元素及锶同位素组成也表现出基性组分与酸性组分混合的特点。采用Ｃ混＝ＫＣ基＋（１—Ｋ）Ｃ酸混合定量模式估算出基性组分占２０％～４０％。由此表明，阿拉善地块西南缘早古生代早期花岗岩的形成，与同一时期或更早时期的基性、中基性岩浆活动可能有着直接的成因联系。

DIORITIC ENCLAVES AND MAGMA MINGLING IN HEXIBAO GRANITE

Some mianthites such as diorite, quartz diorite and basalt distribute in Hexibao granite, rock mass,which is regarded as the product of intermediate-acid magmatic activity on the southwest edge of Alahan massif in Early Paleozoicera. petrographic features of these mianthites imply that they reset from crystallization ofbasic magma components, which were in the same melting state as their host granite, Reequilibrium crystallization temperature and pressune conditions of host and enclaves estimated from geothermbarometer aretremendously similar, The features of mingling between basic and acid magmas can also be inferred frompetrochemistry, rare earth elements and strontium isotop components of the host granite. it is estimated fromthe micing quantitative model formula that the basic magma components account for 20% ~40 %. Therefore, it is suggested that, there has seemingly been a direct genetic relationship between basic or intermediatebasic magma activity and the formation of granite on the southwest edge of Alashan massif in the early stage ofEarly paleozoic era.