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Structural Style of the Thrust Wedge of Northern Tunisia Based on Regional Transects

Sami Khomsi

The Tell domain of Tunisia occupies the eastern part of the “Maghrebides” fold-thrust belt. It corresponds to a nappes domain made by several tectonic units displaced south-eastward. The deformational features are mainly controlled by the mechanical stratigraphy with a set of detachment levels in the sedimentary pile which played a determinant role in the tectonic evolution controlling the structural styles related to thrusting and compressional events acting by the Middle Miocene until now with vertical decoupling and detachment along the different structural levels.

Structural interpretation by cross sections based on seismic lines and field observations, allows us to outline the structural style especially along the thrust front of the Numidian nappe and the Kasseb nappe the easternmost unit of the Tell, and their relationships with the substratum north of the Middle Mejerda valley. Seismic interpretations show also the occurrence of important halokinetic movements deforming both the autochthonous and allochtonous series. Two types of halokinesis related bodies can be distinguished: the first one cutting the autochthonous sedimentary cover, the second one the Tellian sheets specially the Numidian nappe which is the uppermost tectonic unit of the Tell.

A set of regional structural transects crossing the whole Tunisia thrust belt from the Tell to the Gulf of Hammamet and Pantellaria Rift passing through the south-eastern foreland and the Zaghouan thrust-fault allows us to illustrate the overall structural style of Northern Tunisia allowing us to replace our results in the general structural context and the tectonic framework of the Mediterranean basins.

According to structural interpretations and sectioning, we propose guidelines for structural trap concept and finding in the Northern thrust belt of Tunisia.

AAPG Search and Discovery Article #90161©2013 AAPG European Regional Conference, Barcelona, Spain, 8-10 April 2013