Plate reconstruction studies show that the Neotethys Ocean was closing
due to convergence of Africa and Eurasia towards the end of the
Cretaceous. The period around 75 Ma reflects the onset of continental
collision between the two plates, although convergence was still mainly
accommodated by subduction, with the Neotethys slab subducting beneath
Eurasia. Africa was separated from the rapidly north moving Indian plate
by the Owen oceanic transform in the northeast. The rest of the plate
was surrounded by mid-ocean ridges. Geologic observations in large
basins show that Africa was experiencing continent-wide rifting related
to northeast-southwest extension. We aim to quantify the forces and
related paleostresses associated with this tectonic setting. To
constrain these forces, we use the latest plate kinematic
reconstructions, while balancing horizontal gravitational stresses,
plate boundary forces and the plate's interaction with the underlying
mantle. The contribution of dynamic topography to horizontal
gravitational stresses is based on recent mantle convection studies. We
model intraplate stresses and compare them with the strain observations.
We find that slab pull, horizontal gravitational stresses and transform
shear tractions in general acted with the same orientation as the
absolute motion of the African plate 75 Ma. Both the balance between
these three and the other, resistive, forces, and the fit to strain
observations require the net slab pull, as experienced by the plate, to
be low, pointing to the absence of a mature continuous Neotethys
subduction zone at the time. This corresponds well to reconstructions of
micro-continents interfering with the Neotethyan subduction.