Résumé:
The southern Neritic massive of Ain M'Lila constitiue one of the main outcrops of Lower
Crétaceous néritic platform Constantinoise.
They are part of a region located charniére convergene to the external areas of the Alpine
chain Algeria and eastern Atlas area is the flat shape and Constantine notament its southern
borde.
The lithostratigraphic study of Lower Crétceous séries of Monts the Ain M‘Lila enabled
to highlight a carbonate series of Jurrasique going to Aptian terminal. The séries ends with a
hardened surface regional scale, reflecting the emergence of the flat shape to this époquee
with deficiency in the Albian in most of the southern mountains. Often missing the Albian
was reconu massif at Nif Ennser, represented by one hundred meter microconglomératiques
of alternating limestone and marl clear.
On the tectonic map, southern massive plicatves are characterized by more or less largescale structures. These plicatives structures affected by numberous faults which the most
important are the dextral offsets, direction NW- SE.
The sedimentological analysis permits proposed deposition model for the study area from a
microfaciologique and paleoenvironmental analysis.
This analysis allowed reconstituting an internal platform environment shape crossed
by a recif, in which several microfacies, sorted by increasing order bathymetry were
indidualisés.
The internal facies of flat calm as sometimes agitated.
- The supratidal - intertidal facies characterized by mudstone essentillement to wackstone to
calcisphéres.
- The facies of the partially protected lagoon (subtidal) benthic foraminifera in, and milioles
orbitoline and algae.
The reef facies subrécifaux to include:
- The reef facies of reef flat: these are deposits of intraclasts, pellets, oncolites and many
benthic foraminifera).
- Haut-fond facies: include the packstone- grainstone Brayozoaires and rudist, echinidides,
oolites and corals.
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The évolutionon diagénitiques of carbonate sediments of our study area undergoes
transformation diagénitiques trio’s stage:
- Early diagenesis: marked by micritisation formed elements, perforations, biological crusts,
and bioturbations.
- Mésogenése: marked also by chemical compaction (stylolites) and mechanical (fracturing)
and cementation and dolomitization.
- Télogenése: marked by dolomitization, the dédolomitisation and intense fraturation (diaclase
