Integrated gravity and seismic investigations over the Jebel Es Souda-Hmaeima structure: implication for basement configuration of the eastern frontal fold-and-thrust belt of Tunisian Atlasic Mountains

Geophysical Contribution in the Characterization of Deep Water Tables Geometry (Sidi Bouzid, Central Tunisia)

“…Thus, the regional gravity maps were chosen ( Figure 5). The gravity gradient observed in the regional gravity map delineates two gravity domains: (1) a positive domain corresponding to the Jebel Es Souda-Hmaeima due to the deep structures affecting the ante-Triassic levels; these results confirm those determined by Tanfous et al [3], and (2) a negative domain covering the Ouled Asker syncline with persistence of a less important negative anomaly (Oued El Hajel). Therefore the regional gravity anomaly will be subtracted from the Bouguer gravity anomaly in order to obtain the residual gravity map ( Figure 6).…”

“…The gravity data that has been used for the current study were obtained from the Office National des Mines (ONM). The free-air and Bouguer corrections were made using the sea level as reference and the average density was fixed to 2.4 g/cm 3 . In order to elaborate the complete Bouguer map of the zone, a grid was performed using the gravity data with a spacing of 1 point per Km 2 .…”

“…The Jebel Es Souda-Hmaeima is a rather short Atlasic anticline which could be compared with a dome. According to Tanfous et al [3] it is a "back folded anticline" affected by kilometric faults oriented NS, NW-SE, and EW [4].…”

Discussion and comments on “Filtering of the gravimetric anomalies to the study of the geological structures of Oued Zarga (Septentrional Tunisia): structural implications”, Arab J Geosci (2012) 5:169–180 by A. Ayed, M. Ghanmi and F. Zargouni

“…It seems that there is a controversy among Tunisian researchers relative to the mean density of Triassic diapirs. AGZ and Hamdi-Nasr et al (2009) Tanfous et al (2010) used a mean density ρ02.27 g/cm 3 . The use of a high mean density (2.51 or 2.58 g/cm 3 ) for the Triassic evaporites is probably done to explain the positive anomalies observed over some diapiric structures in Tunisia.…”

“…It should be noted that Benassi et al (2006) have elegantly explained and modelled in the case of Jebel El Mourra, a diapiric structure causing a positive gravimetric anomaly with a mean density ρ02.27 g/cm 3 . Tanfous et al (2010) also modelled the positive gravimetric anomaly over the Jebel Es Souda-Hmaeima structure with a mean density ρ02.27 g/cm 3 using seismic reflexion constraints. The mean density ρ02.27 g/cm 3 for Tunisian Triassic diapirs is very close to their northeastern Algerian counterparts.…”