Al Jabal Al Akhdar is a NE/SW- to ENE/WSWtrending
mobile part in Northern Cyrenaica province and is
considered a large sedimentary belt in northeast Libya. Ras
Al Hilal-Al Athrun area is situated in the northern part of
this belt and is covered by Upper Cretaceous–Tertiary
sedimentary successions with small outcrops of Quaternary
deposits. Unmappable and very restricted thin layers of
Palaeocene rocks are also encountered, but still under
debate whether they are formed in situ or represent
allochthonous remnants of Palaeocene age. The Upper
Cretaceous rocks form low-lying to unmappable exposures
and occupy the core of a major WSW-plunging anticline.
To the west, south, and southeast, they are flanked by highrelief
Eocene, Oligocene, and Lower Miocene rocks.
Detailed structural analyses indicated structural inversion
during Late Cretaceous–Miocene times in response to a
right lateral compressional shear. The structural pattern is
themed by the development of an E–W major shear zone
that confines inside a system of wrench tectonics proceeded
elsewhere by transpression. The deformation within this