The Hammamet, Gabe `s and Chotts basins (Tunisia): a review of the subsidence history Martin Patriat a , Nadine Ellouz a, * , Zied Dey b , Jean-Michel Gaulier a , Hatem Ben Kilani b a Institut Franc ßais du Pe ´trole, 1 –4 Avenue de Bois Pre ´au, 92852 Rueil-Malmaison cedex, France b Entreprise Tunisienne d’Activite ´s Pe ´trolie `res, BP 367, 1002 Tunis, Tunisia Received 20 October 1999; received in revised form 4 July 2001; accepted 19 July 2002 Abstract We modeled the subsidence of three Mesozoic basins in Tunisia by using well data, seismic lines and field data. The results are presented here with an attempt to relate the succession of events deduced from the subsidence evolution analysis to the geodynamic evolution of the northern African margin. The Mesozoic and Cenozoic geological history of Tunisia has been broken down into two major periods separated by a transition period. The first period from Trias to Aptian was characterized by a constant subsidence of variable intensity spread over most of Tunisia, and over all the studied basins. This period was dominated by extension accompanying the Tethyan rifting during Trias – Lias. The transition period during the upper Cretaceous was characterized by extension and by the weak effects of far-seated compressional events. It is coeval with the first appearance of salt mobilization. The last period, in Tertiary, marked the appearance of the major collisional events, mostly during Neogene. During this last period, basins were characterized by very different behaviour, depending on their location: East or West of the North–South axis and close or not to the Tellian nappes. Among the three basins we studied, we paid special attention to the southernmost Gabe `s basin located south of the present eastern margin of Tunisia. The first-order evolution of its subsidence is similar to that we infer for most of the Tunisian basins. We emphasize the role of the structuration of the Gabe `s basin in the partition of the subsidence through time. D 2002 Elsevier Science B.V. All rights reserved. Keywords: Tunisia; Maghreb; Atlas; Subsidence modeling; Tectonic controls; Paleostress field 1. Introduction The present-day margin of North Africa repre- sents the southern margin of the Miocene western Mediterranean basin. The original southern margin of the Tethyan Ocean, Triassic to Lower Jurassic in age, has been highly tectonized during Cenozoic. At present, the paleomargin is represented in the Atlas regions of the Maghreb. This paper aims to bring out elements about the geological history of the Tethyan margin by a study of its subsidence through time. It focuses on the evolution of Tunisian basins located on the ancient Tethyan margin. We used industrial wells, seismic 0037-0738/02/$ - see front matter D 2002 Elsevier Science B.V. All rights reserved. PII:S0037-0738(02)00290-7 * Corresponding author. Fax: +33-1-47-52-70-67. E-mail address: nadine.ellouz@ifp.fr (N. Ellouz). www.elsevier.com/locate/sedgeo Sedimentary Geology 156 (2003) 241 – 262