The low-grade metamorphism of the sedimentary cover of the Moroccan
Anti-Atlas is investigated using Illite crystallinity (IC) method. More
than 200 samples from three key areas (southwestern, central and eastern
Anti-Atlas) have been taken from a maximum of different stratigraphic
levels and have been analysed. The metamorphism is of low to very low
degree throughout the southern flank of the Anti-Atlas. It increases
from northeast to southwest. Whereas in the eastern Anti-Atlas
diagenetic and anchizonal IC-values are predominant, in the western and
central Anti-Atlas also epizonal IC-values are found. In every
respective area the IC improves with stratigraphic age. At the scale of
the entire Palaeozoic Anti-Atlas basin the IC correlates best with
estimated paleo-overburden. However, burial metamorphism cannot be the
cause even though considering missing sedimentary pile of Late
Carboniferous age. The `abnormal' paleo-geothermal gradient of 43-35
O/km we evidenced for the Carboniferous is a true one, and has to be
related to a basement sequence enriched in heat producing elements such
as series of the West African Craton.