关于富碱侵入岩

ON THE ALKALI-RICH INTRUSIVE ROCKS

富碱侵入岩主要包括碱性岩、碱性花岗岩,也包括碱含量高的碱长花岗岩。碱性花岗岩与碱长花岗岩称为A型花岗岩。富碱侵入岩的含矿潜力不亚于S型和I型花岗岩类。其常呈线型展布,规模可观,受区域大断裂控制。赋存于裂谷、地堑、地幔上拱带的拉张条件下。S型、I型和A型花岗岩在同一造山旋回不仅有时间演化关系,在空间上无论在华南或阿尔泰地区,以S→I→A的空间推移带朝向大陆边缘活动带。富碱侵入岩相对富Nb、U、Th、Zr、Sn、Ga、Zn和REE。组成物质来自上地幔部分熔融岩浆,顺大断裂上升,硅铝层混染较小时形成碱性岩。

The alkali-rich intrusive rocks are mainly consisted of alkalic rocks and alkalic granites, also include the alkali feldspar granites. The latter two can be named as A-type granites. The mineralization potentiality of the alkali-rich intrusives is as well as that of the S-type and I-type granitoids. The alkali-rich intrusives are generally large in scale. They usually show as linear distribution and are controlled by the regional faults, and occur in the rift, graben andupwarped belt of mantle under tensional environment. The S-Type. I-type and A-type granites in the same orogenic cycle have their temporal evolution relationship. The S-type →I-type →A-type spatially are evolved from the internal part of continent to the active belt of continental margin. The alkali-rich intrusives are rich in Nb , U ,Th, Zr, Sn, Ga. Zn, and REE.The rock-genetic materials are the alkali-rich magma formed by partial melting in upper mantle and then uprised along the large faults to form the alkalic rocks when the contamination of sial lesser or to form alkalis granites wk when conta-mination of xial was relatively serious.