Neogene-Quaternary structuring of the Kalaa Khesba Graben, northwestern Tunisia: A push-up inversion structure

Amira Rjiba (1, 2, 3) , Tahar Aifa (2) , Hakim Gabtni (3) , Mohamed Ghanmi (1) , Achref Boulares (4)

1 UTM - Université de Tunis El Manar
2 GR - Géosciences Rennes
3 CERTE - Centre de Recherche et Technologies des Eaux
4 ETAP - Entreprise Tunisienne d'Activités Pétrolières

Interpretation of lithostratigraphic, seismic and gravity data from Kalaa Khesba Graben shows (i) lateral and in-depth variation of the lithostratigraphic series, (ii) complex structuring of faulting. Reverse faults affected Paleocene to Quaternary horizons with a duplication of Eocene-Paleocene series occurred at subsurface evidenced within well W6. Isochron, isovelocity and isobath maps, combined with gravity data, show subsurface structures oriented predominantly NW-SE to NS and NE-SW to EW. Faults and horizons on the seismic lines, superimposed to gravity lineaments, reveal negative anomalies occurring at shallow depth. Such features may reflect the existence of low density Neogene-Quaternary series, strike-slips and thrust faults within Kalaa Khesba Graben. Depths deduced from Euler deconvolution solutions vary from 0.5 to 4 km. At subsurface, well log data located in the center of the graben, ensured the presence of Triassic bodies. A model of initiation of Kalaa Khesba Graben through a N160° σ1 transpression is proposed.

Mots clés: Pull-apart; Strike-slip; Lithostratigraphy; Gravity; Seismic reflection

Domaines: Stratigraphie; Géophysique [physics.geo-ph]; Tectonique

Amira Rjiba, Tahar Aifa, Hakim Gabtni, Mohamed Ghanmi, Achref Boulares. Neogene-Quaternary structuring of the Kalaa Khesba Graben, northwestern Tunisia: A push-up inversion structure. Journal of Petroleum Science and Engineering, 2019, 183, pp.106432. ⟨10.1016/j.petrol.2019.106432⟩. ⟨insu-02277921⟩