Albian extrusion evidences of the Triassic salt and clues of the beginning of the Eocene atlasic phase from the example of the Chitana-Ed Djebs structure (N.Tunisia): Implication in the North African Tethyan margin recorded events, comparisons

Abstract

In the northern part of Tunisia, close to Testour/Slouguia, new observations and updated biostratigraphy make it possible to highlight the relation between the Triassic saliferous mass and the surrounding Mesozoic beds (T. M.). Near the (T. M.) boundary, the formations observed consist dominantly of Triassic evaporites reworked in the Early and Late Albian deep-water sedimentary deposits. Throughout the studied area, Jurassic rocks are absent. We propose to interpret the Chitana-Ed Djebs structure originally emplaced as gravitational stretch masses in a passive margin in the same way as the salt bodies of widespread salt province in the Gulf of Mexico. A reconstructed schematic position of the Chitana-Ed Djebs salt body displays a scenario of setting of the salt mass on a submarine palaeo-slope. Moreover, the starting clues of the paroxysmal event of the Late Mesozoic tectonic inversion clearly fossilized through the discordance of the Middle Eocene-Early Lutetian limestone on the Albian series. To cite this article: M.-M.

Tectonomagmatic Context of Sedex Pb–Zn and Polymetallic Ore Deposits of the Nappe Zone Northern Tunisia, and Comparisons with MVT Deposits in the Region

“…In that case, the ore-forming fluids would be delivered onto or near the surface at the time of diapiric piercing, or close thereafter (Sheppard et al 1996, and references therein). As diapiric salt extrusion is documented in Tunisia from the Albian (Ben Slama et al 2009) to the Latest Cretaceous (Ben Mehrez et al 2009); by this model the ore-forming event would have occurred no earlier than latest Cretaceous (or Early Paleocene). Another way to explain the relationship between the diapirs and the Pb-Zn-Ba-F deposits is to consider the latter as MVT mineralization that formed by typical post-collisional gravity-driven fluid flow (e.g., Leach et al 2001Leach et al , 2005.…”

“…Within the Dome Zone, the evaporitic diapirs are rooted in Triassic strata. The first extrusions occurred as soon as the Albian (e.g., Ben Slama et al 2009). However, the main diapiric emplacement was coeval with the Atlasic inversion (Late Cretaceous to Paleocene), followed by reworking of the resulting bodies during the Late Miocene (Perthuisot et al 1999).…”

Tectonosedimentary evidence in the Tunisian Atlas, Bou Arada Trough: insights for the geodynamic evolution and Africa–Eurasia plate convergence

“…During both extensional and compressional phases this Triassic salt has been remobilized throughout the pre-existing system of faults. Some of these salt structures are considered as diapirs (Gharbi et al 2005) in which salt occupies the core of the anticlines, and others as salt glaciers Ben Slama et al 2009) in which Triassic evaporites were interstratified within the Aptian clay series. These salt structures started to grow during the Aptian (Snoke et al 1988;Perthuisot et al 1998) or even earlier (Boukadi & Bedir 1996).…”

Gravimetric Study of Geological Structures of Teboursouk Area, Northern Tunisia

“…The Neogene formation is composed of Miocene marls. The Pliocene-Quatenary series shows a conglomeratic beds on the base and of sandy clay ones on the top [35,[41][42][43][44][45][46].…”

“…The Early Cretaceous strata are composed of Late Aptian-Early Albian sediments with black clayey marls. In addition, the Late Cretaceous is represented by Cenomanian (marls) to Senonian series (limestones and marls) [28,41]. The Cenozoic deposits (Paleocene to Oligocene time) are composed of marls, limestones, and sandstones.…”