Contrôle tectonique de la sédimentation néogène dans la zone des diapirs de Tunisie septentrionale

Abstract

Les séries sédimentaires sont constituées au Néogène de formations marines de milieu peu profond, au cours du Miocène inférieur et moyen, et laguno-continentales dans l'intervalle Miocène supérieur-Pliocène. Ces séries s'ordonnent en trois cycles majeurs, à bases érosives et discordants entre eux, reflétant surtout le contrôle de la tectonique. L'analyse de la distribution des dépôts dans la région du Kef montre que la tectonique est compressive et se traduit par la surrection d'anticlinaux d'amortissement décollés dans les évaporites du Trias.

New insights on the structural style of the subsurface of the Tell units in north-western Tunisia issued from seismic imaging: Geodynamic implications

“…Actually, Yaich et al, [43] locate a high zone around the ''Zone des Dômes'' where Oligo-Miocene series locally pinch out. In addition, many works emphasize the occurrence of reworked Triassic material in the Paleogene series around the diapirs [11,13,17,38,41] in agreement consistently with earlier piercement of the Triassic salt.…”

“…This section striking NW-SE stretches from the Mediterranean coast in Tabarka in the northwest, to the Zaghouan thrust-fault in the eastern Atlas. It is obtained by a compilation of seismic sections [13,24,[26][27][28]30,31] petroleum wells, field investigations of our predecessors [1,2,9,11,13,14,17,21,22,31,32,[36][37][38][39][40][41] and geological mapping [11,14,22,[36][37][38][39][40]41]. The section shows that the Tell thrust belt is made by a set of tectonic displaced units with the Numidian unit occupying the upper-most structural level of the belt.…”

“…On the other hand, different studies emphasised the occurrence of Triassic salt movements in northern Tunisia [2,3,11,14,17,26,28,31,32,[35][36][37][38][39][40]41] and beneath the ''nappe'' [37], especially beneath the Numidian flysch [2,14,38]. Nevertheless, the subsurface structural style remains questionable because of the scarcity of the seismic records, which remains a limiting factor to decipher the structural subsurface style at depth and to have a general overview of the area.…”

Subsurface geology of the Ariana region (Diapir Zone, northern Tunisia) by means of gravity analysis

“…Tunisia is a key site in the north‐western African passive margin since it is located at the junction between the eastern and western Mediterranean domains and straddles the orogenic domain as well as the Sahara platform (Castany 1956; Wildi 1983; Ben Ayed 1986; Chihi 1995; Bouaziz et al 2002; Chikhaoui 2004; Guiraud et al 2005).…”

“…The complete inversion of the north-western African continental margin was developed during the Miocene in relationship with N120 compression constraints (Castany 1956;Wildi 1983;Ben Ayed 1986;Boukadi 1996;Frizon de Lamotte et al 2000;Bouaziz et al 2002;Bracène and Frizon de Lamotte 2002;Chikhaoui 2004). The Miocene tectonism has played an important role in the structural architecture of Tunisia.…”