Cenozoic dynamics of the African plate with emphasis on the Africa-Eurasiacollision

We investigate the forces acting on the African plate from about 56 Ma to t he present-day. We aim (1) to establish a basis for quantification of the o verall dynamics of the Mediterranean/Middle East region and (2) to understa nd how Africa reacts to temporal variation in the forces associated with th e Africa-Eurasia collision. We use the assumption of dynamical equilibrium which implies that at any given time, the net torque of forces on Africa's northern margin must have been balanced by the other torques acting on the plate. Moreover, temporal variation in the forces on Africa's northern marg in must have been balanced by contemporaneous changes in one or more of the other torques. By quantifying those "other" torques we may derive a constr aint on the forces at the northern mai-gin. We expect the Africa-Eurasia co llision to have been associated with changes in the associated forces and e xamine how these changes are balanced. Using alternative parameterizations, we calculate the net torque of ridge push, transform fault resistance, and basal drag. We also quantify changes in the torque of forces associated wi th the continent-ocean transition. The results constitute a framework for d etailed dynamic models of the Africa-Eurasia convergence zone. Temporal cha nges in the ridge push torque prove to be small. The torque of transform re sistance does change, but these changes do not relate to forces at the nort hern margin. Evidence for a relation with collision is found only for the c ase of basal drag. The results point to a mechanism where the plate maintai ns its dynamical equilibrium mainly through collision-induced changes in ab solute motion.