The BGB is contained within part of a larger system called the Barberton Granite Greenstone Terrain (BGGT) which includes two main components; the [[supracrustal]] succession, which defines the BGB portion, and the deeper-level intrusive units that surround the BGB.
The BGB consists of locally derived sediments and chemical sediments, but is composed mostly of TTGs and greenstones, as briefly discussed above [REF].