Journal of African Earth Sciences 171 (2020) 103956 Available online 23 July 2020 1464-343X/© 2020 Published by Elsevier Ltd. Gravity contribution to the Mejerda foreland basin, Northwestern region of Tunisia Nesrine Frifita a, b, * , Kevin Mickus c , Mohamed Gharbi d a Department of Geology, Faculty of Sciences, University of Tunis El Manar, Tunis, Tunisia b Department of Earth Sciences, Faculty of Sciences, University of Gab`es, Gab`es, Tunisia c Department of Geosciences, Missouri State University, Springfield, MO, 65897, USA d Geo-Resources Laboratory, Centre of Research and Technology of Water, Borj Cedria, Soliman, Tunisia A R T I C L E INFO Keywords: Gravity Thin-skinned tectonics Mejerda wedge-top basin Tunisia ABSTRACT The Mejerda basin in northwestern Tunisia is located between the Tell and Atlas Mountains and contains structures related to the complicated tectonic history of the study region. The Mejerda contains compressional structures related to the Cenozoic collision between Europe and Africa, and strike-slip faults related to exten- sional tectonics. As a result of the varied tectonic history, there has been numerous models of the basin formation ranging from simple grabens, pull-apart basins and foreland basins. In order to constrain the subsurface structure of the basin, a gravity analysis consisting of the construction of residual gravity anomaly maps, estimated depths from upward continuation and Euler deconvolution, and detailed two-dimensional forward models. The gravity analysis was constrained by a seismic reflection profile and a deep well. The map analysis indicated two separate basins, one called the Quaternary basin and another called the Pliocene basin. Based on the gravity depth an- alyses and the gravity forward modeling, and the residual gravity anomaly map, these basins were between 2.5 and 3 km thick, and separated by gravity maxima probably due to uplift of Triassic and Cretaceous sediments related to compressional tectonics and evaporitic movement. The Euler deconvolution analysis imaged a number of lineaments, interpreted to be faults, that trend in the NE and NW directions and these faults basically delineate the basins. Results confirm that the Mejerda basin is a wedge-top basin located in the foreland side of the Tellian thrust belt and consists of two separate basins whose origin was mostly determined by thin-skin compressional tectonics. 1. Introduction The Mejerda basin is a foreland basin (Fig. 1) situated between the Tell Mountains to the north and the northern Atlas Mountains to the south. The basin is part of the Maghrebides orogenic chain which was formed during the Miocene-aged crustal shortening period (Bouaziz et al., 2002). This crustal shortening period produced numerous thrust sheets and included dextral transpression that produced a series of strike-slip faults (Guiraud et al., 2005). The Mejerda basin which be- longs to the Tellian domain (Amiri et al., 2011) is bounded by thrust sheets on its northern boundary and contains numerous Triassic diapiric salt structures along the southern part of the basin. These diapiric structures belong to the northeastern Maghreb salt province (Bolze, 1954; Vila et al., 1994, 1996; Ghanmi et al., 2006; Masrouhi et al., 2013). The Mejerda basin has been considered a graben bounded by E-W oriented normal faults (Castany, 1954). However, recent studies have further investigated the regional structures and showed that the numerous E-W trending faults were reactivated by strike-slip faulting to produce pull-apart basins (Chihi, 1995). Other studies have indicated that the Mejerda basin is a foreland molassic basin delimited by East and North and NE-trending faults and whose major basinal features were formed by crustal shortening (Rouvier, 1977; Perthuisot, 1978; Ben Ayed, 1994; Dlala, 1995; Ould Bagga, 2003; Amiri et al., 2011; Gabtni et al., 2016). Recently the basin was considered as a wedge-top basin which developed during the growth of the Tell and Atlas thrust belts (Booth-Rea et al., 2019; Khelil et al., 2019) and occurs on the frontal part of the foreland basin system over the advancing thrust belts (Decelles and Giles, 1995). The purpose of this study is to define the geometry of Mejerda * Corresponding author. Department of Geology, Faculty of Sciences, University of Tunis El Manar, Tunis, Tunisia. E-mail address: frifitanesrine@yahoo.fr (N. Frifita). Contents lists available at ScienceDirect Journal of African Earth Sciences journal homepage: www.elsevier.com/locate/jafrearsci https://doi.org/10.1016/j.jafrearsci.2020.103956 Received 17 April 2020; Received in revised form 14 July 2020; Accepted 14 July 2020