Jl. Morel et al., Neogene and Quaternary deformation of the northern High Aatlas border [Morocco]: role of the basement and structural consequences, J AFR EARTH, 30(1), 2000, pp. 119-131
According to major discontinuities, continental deposits in the Cenozoic At
las basins are subdivided into three groups (pre-, syn- and post-tectonic).
Progressive unconformities are the main characteristic of the syntectonic
formations, implying that the Atlas tectonic episode is synchronous with Ne
ogene and Quaternary sedimentation. This tectonic episode is responsible fo
r the inversion of Early Mesozoic extensional structures within the basemen
t, which were reactivated into symmetrical thrusts or transpressional fault
s. Shortening of the basement induced the detachment of the cover. Deformat
ion of the cover is expressed by thrust faults (with southern and northern
vergences), folds and flexures linked to blind thrusts. Kinematic data show
that the main regional compression was directed N150+/-10 degrees during t
he Neogene and north-south during the Quaternary. The involvement of the up
per crust, in the Alpine Atlasic Belt, contributed to create areas of high
relief. The High Atlas can be interpreted as resulting from large Cenozoic
thrusts, and compared with the Pyrenean Axial Zone, although their pre-Ceno
zoic histories can differ markedly. (C) 2000 Elsevier Science Limited. All
rights reserved.