Abstract
Evaporite, carbonate and siliciclastic transitions occur within the Jurassic deposits of southeastern Tunisia. These facies are grouped into four major transgressive-regressive sequences corresponding to various environments of deposition. The latter include sabkha, subaqueous evaporite basin, carbonate tidal flats to shallow marine platform, bioherms and mixed siliciclastic ramp. Rapid lateral and vertical variations in thicknesses and facies are controlled by tectonic, climatic and eustatic factors. East-west and NW-SE fault systems generated a down-faulted graben (Tataouine basin) bordered by two uplifted horsts (Tebaga Mole and Libyan Craton) and have acted as an evaporite depocenter or as a siliciclastic trap. Eustatic-related transgressions occurring during Late Lias, Bajocian, Early/Middle Callovian, and probable Upper Callovian-Oxfordian have led to opening and/or deepening of the marine basin accompanied by carbonate sedimentation rapidly replacing evaporite or siliciclastic deposition. This Jurassic example not only confirms that tectonics and, to a lesser extent, climate largely controlled evaporite, carbonate, and siliciclastic transitions; it also demonstrates that sea-level changes may be another factor controlling such transitions in these ancient deposits.
Published Version
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