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扼于雅鲁藏布江大拐弯内侧的喜马拉雅东端是一个受断层控制的独立构造岩层体，由结晶基底变质杂岩构成。该地体于喜马拉雅造山时期呈北东斜向板内逸脱，进而向冈底斯岩浆弧横推楔进，构成印度斯河—雅鲁藏布江缝合线转折部核心。该区基底岩系由富铝硅酸盐及钙硅酸盐结晶杂岩组成。岩层已受复杂的多期褶皱叠加和断裂变形，具强烈混合岩化态征。运用“构造—地层学“方法将区内变质岩系划分为多雄拉片麻岩组和阿尼桥片岩组，分别代表下部和上部二套不同层次的结晶岩序列，并将其归并为南迦巴瓦岩群。与此同时，对基底岩系的建造特征进行了分析讨论。同位素年龄测定表明，南迦巴瓦岩群的原岩形成于中元古代
The east end of the Himalayas, straddling the inside of the Great Bend of the Brahmaputra, is a fault-controlled, independent tectonically-formed rock body composed of crystalline basement metamorphic complexes. During the Himalayan orogeny, the terrain escaped into the northeast slant plate and then wedged toward the Gangdise magma arc. This formed the core of the junction of the Indus River-Brahmaputra suture. The basement rocks in the area are composed of alumino-aluminosilicates and calcium-silicate crystalline complexes. Rock formations have been subjected to complex multistage fold superimposition and fault deformation with strong mixed petrified signatures. The tectono-stratigraphy method is used to classify the metamorphic rocks in the area into the Dorico-Gneiss and Aniqiao schist group, representing two sets of different sequences of crystalline rocks in the lower part and the upper part respectively, which are merged into South Jabbawa rock group. At the same time, the construction characteristics of the basement rock series are analyzed and discussed. Isotope age determination shows that the original rock of the Namjagbarwa Group formed in the Mesoproterozoic