The global gravity field obtained from the observations of the
satellite Gravity Field and Steady-State Ocean Circulation Ex plorer (GOCE) satellite offers new opportunities in defining den sity variations of earth’s crust and mantle, allowing new insights
into the structure of specific geologic features. The Central Afri can Rift is a key feature in understanding the dismemberment of
Gondwana, and we contribute to defining the crustal density struc ture underlying the rift. The presence of a narrow and up to 12 km
deep basin implies crustal stretching allowed the sediment to ac cumulate, but a key question is whether the stretching processes
also affected the deeper layers of the crust or was limited to the
upper crust. The study area includes a subbasin of the greater Chad
sag basin, which extends over 1500 × 1500 km and occupies the
center of North-Central Africa, shared between the countries of
Chad, Sudan, Nigeria, Niger, Algeria, Libya, and Cameroon. We
find that the rifting affected the lower crust of the West African Rift,
and we evaluate evidence for a 1500 km long and several km thick
magmatic crustal intrusion presumably associated with underplat ing and crustal thinning. We estimate that the stretching factor must
be at least 1.5 and had affected the entire crust. To our knowledge,
the identification of a continuous body of magmatic intrusions is
new and has been only possible through the recent global gravity
field. The magmatism has altered the thermal conditions from the
time of emplacement on, and it is relevant for the maturation of
hydrocarbons present in the sediments. The timing of the magma tism is presumably tied to two pulses of volcanism documented in
the rift, associated with the first postrift phase from 96 to 88 Ma and
the second postrift phase from 23 Ma up to the Quaternary
