(a) Position of cratons within Africa. (b) Schematic geological map of the Central Africa fold belt adapted from Milesi et al. (2004); Toteu et al. (2001, 2004) and Saha Fouotsa et al. (2019). Age of representative plutonic rocks are indicated as follow: pre- to syn-orogenic subalkaline rocks (> 600 Ma), anatectic peraluminous granites and post collisional high-K calc alkaline rocks (< 600 Ma). Inset in the Ouaddaï massif shows the location of map drawn in Figure 2. References are cited in the text.