Abstract

This paper presents a detailed tectonic analysis of the Jebel Bou Khil, formerly interpreted as a diapiric structure crowned by a large saliferous Triassic overhanging. In the present study two tectonically superimposed units separated by an overthrust are distinguished. The upper unit includes a large Albian submarine "salt glacier" within a well characterized stratigraphic succession ranging from uppermost Aptian to Turonian. The lower unit shows a disseminated synsedimentary or early diagenetic mineralization of sphalerite within Maastrichtian white limestones together with typical evaporitic celestite deposited in detrital beds of Upper Palaeocene to Lutetian age. This unit is interpreted as a normal sequence overturned during the Tertiary folding. The core of the Bou Khil mine anticline is well dated by lower Maastrichtian marls but not by Palaeocene, as it was previously proposed. This observation argues against an antiformal syncline interpretation. The Bou Khil overthrust can represent the tectonic superimposition of two different neighbouring halokinetic structures, possibly related to the emergence of the frontal "Teboursouk decollement". The Teboursouk decollement separates the northern "salt glaciers" domain from the southern "typical diapirs" domain. This interpretation clearly argues against a diapiric overhanging model.

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