Late Visean to Late Bashkirian Fusulinids (Foraminifera) From Kirchaou KR-1 Borehole Southern Tunisia

Abstract

The study of the Carboniferous foraminifera of the Kirchaou KR-1 borehole allowed to define and delineate the Bashkirian interval in Tunisia. A biozonation, which includes six subzones, is proposed. The Mississippian-Bashkirian transition is located at 2730 m. The Bashkirian-Moscovian boundary, characterised by the presence of the zonal markers Tikhonovichiella and Citronites, is found at 2517 m. Bashkirian covers the interval from 2730 m to 2517 m. The comparison with the BMT-1 borehole, and other wells in the area, helps provide the intervention of the Hercynian orogeny, which locally eroded all the previous Carboniferous deposits, and in some boreholes parts of Mississippian or Pennsylvanian sediments. A comparison of Mississippian fossil assemblages indicates that Tunisia belongs to the western-Tethyan bioprovince like Cantabric Cordillera (Spain) and Donbas (Ukraine) during the Bashkirian.