TITLE:
Paleogeographic Reconstitution and Tangential Tectonic in the Backland of Tunisian Dorsal (Fahs Area: J. Rouas and Ruissate)
AUTHORS:
Aymen Arfaoui, Kais Aridhi, Sabri Aridhi, Mohamed Ghanmi, Fouad Zargouni
KEYWORDS:
Tunisian Dorsal Backland, Paleogeographic Reconstitution, Unconformities, Synsedimentary Faults, Thrust Tectonic, Decollement Level, Ramp Folds, Fault Propagation Fold
JOURNAL NAME:
International Journal of Geosciences,
Vol.7 No.3,
March
2,
2016
ABSTRACT: The Tunisian Dorsal backland is the
Eastern Atlas side of maghrebides. Field data of Fahs area allowed us to
develop new interpretations and to characterize the main structural features of
the studied devices (Jebel Rouas and Ruissate). Heritage of Zaghouan accident,
Triassic salt movements and strike-direction of major synsedimentary faults are
the principal causes and results of the skinned and superimposed geometric
architecture, generated by the reversed extensional (Jurassic-Cretaceous)
tectonics. The actual geometry of Jebel Rouas and Ruissate represents a fault
propagation fold, affecting Jurassic and Cretaceous sets. The backland of this
thrust fault defines an imbrications structures of Barremian series. Tectonic
records activities show the existence of angular unconformities (Oligocene and
Eocene series on the Cretaceous sets considered as bedrock), slumps, tectonic
breccias and synsedimentary faults are all of them controlled by a deep major
accident; N-S to NE-SW and NW-SE. Features of the study area are probably
related first; to the blockage of Zaghouan thrust oriented NE-SW in the
foreland; then, to the intense halokinetic activity, which facilitates the
layers displacement acting as decollment level. The detailed structural and
stratigraphic study of Fahs area and its neighbors shows the presence of an
intense tangential tectonic during upper Miocene, affecting Meso-Cenozoic sets,
because all the structures involved are sealed by Oligocene and Miocene thinned
series. This is accentuated by the existence of different sets of decollment at
different depths, which are represented by a displacement to the SE through the
backland of the Tunisian Dorsal. We define these features as an imbrication and
thrusting Out of sequence system.