The pyrolysis of the T layer oil shales of Timahdit (Morocco) was carried o
ut for two reasons. Firstly, using gas chromatography, the contents of the
various gases given off during this pyrolysis have been determined. Then, a
ccording to Rock-Eval pyrolysis results of the crude oil shales and their i
solated kerogen, it has been concluded that these oil shales are located to
wards the beginning of the evolution of type II, have a marine origin and p
resent qualities of a good mother-rock. Their content of polar compounds is
more important than that of the hydrocarbon compounds. (C) 2001 Academie d
es sciences / Editions scientifiques et medicales Elsevier SAS.