P>To put constraints on the Mesozoic to recent growth of the Anti-Atlas
system, we investigated the temperature-time history of rocks by
applying extensive low-temperature thermochronological analysis to three
Precambrian inliers along the coast and 250 km into the interior.
Bedrocks yield old U-Th/He ages on zircon (248-193 Ma) and apatite
(150-50 Ma) and also fission-track ages of 173-121 Ma on apatite. These
datasets are interpreted as recording passive margin upward movements
from central Atlantic rifting until the Early Cretaceous. A phase of
sedimentary burial was evidenced for the Cretaceous-Eocene. The
extension of this thin (1.5 km) basin is loosely constrained but can be
extended to the western regions of northern Africa. Effects of the
existing thermal perturbation of lithospheric origin 100 km below the
Atlas show that the 120-60 degrees C isotherms are not much deflected.
Large-scale uplift has possibly occurred in the western Anti-Atlas since
c. 30 Ma and is associated with a mean denudation rate of 0.08 km Ma-1.