Recently, the continually increasing availability of seismic data has
allowed high-resolution imaging of lithospheric structure beneath the
African cratons. In this study, S-wave seismic tomography are combined
with high resolution satellite gravity data in an integrated approach to
investigate the structure of the cratonic lithosphere of Africa. A new
model for the Moho depth and data on the crustal density structure are
employed along with global dynamic models to calculate residual
topography and mantle gravity residuals. Corrections for thermal effects
of an initially juvenile mantle are estimated based on S-wave tomography
and mineral physics. Joint inversion of the residuals yields necessary
compositional adjustments that allow to recalculate the thermal effects.
After several iterations, we obtain a consistent model of upper mantle
temperature, thermal and compositional density variations, and Mg# as a
measure of depletion, as well as an improved crustal density model. Our
results show that thick and cold depleted lithosphere underlies West
African, northern to central eastern Congo, and Zimbabwe Cratons.
However, for most of these regions, the areal extent of their depleted
lithosphere differs from the respective exposed Archean shields.
Meanwhile, the lithosphere of Uganda, Tanzania, most of eastern and
southern Congo, and the Kaapvaal Craton is thinner, warmer, and shows
little or no depletion. Furthermore, the results allow to infer that the
lithosphere of the exposed Archean shields of Congo and West African
cratons was depleted before the single blocks were merged into their