The folded zone (unstable shelf) contains three tectonic
zones which are, from west to east: the Mesopotamian Zone
(Quaternary molasses and buried structures), the Foothill Zone
(Neogene molasses and long anticlinal structures separated by
broad synclines), and High Folded Zone (Paleogene molasses
and harmonic folded structures). These longitudinal tectonic
zones are segmented into blocks bounded by ENE-WSW
(shifting to NE-SW) transverse faults with both vertical and
horizontal displacement (Jassim et al., 1999). The transverse
blocks have been active at least since the Late Cretaceous and
strongly affected the sedimentary facies of the Cretaceous and
Tertiary sequences (Numan, 1997). According to the tectonic
division of Iraq (Numan, 2001), the area under study covers
the Foothill and Mesopotamian zones of the quasiplatform
foreland of Iraq (Fig. 2). The main axis of the basin is NW-SE
in which the sandy and clayey facies of the Late Miocene
Injana Formation envelope the contemporaneous evaporatic
facies of the Middle Miocene Fat’ha Formation (Al-Mashadani,
1984)).