|The Upper Cretaceous of the Kalaat Senan region, Central Tunisia.Integrated litho-biostratigraphy based on ammonites, planktonicforaminifera and nannofossils zones from Upper Turonian to Maastrichtian|
Robaszynski, F.; Donoso, J.M.G.; Linares, D.; Amedro, F.; Caron, M.; Dupuis, C.; Dhondt, A.V.; Gartner, S. (2000). The Upper Cretaceous of the Kalaat Senan region, Central Tunisia.Integrated litho-biostratigraphy based on ammonites, planktonicforaminifera and nannofossils zones from Upper Turonian to Maastrichtian. Bull. Cent. Rech. Elf Explor. Prod. 22(2): 359-490
In: Bulletin du Centre de Recherches Elf Exploration Production. Elf-Aquitaine: Pau. ISSN 1279-8215, more
lithostratigraphy; biozones; ammonoids; Foraminifers; planktonic taxa;coccoliths; Inoceramidae; Senonian; Tunisia; Kalaat Senan
|Authors|| || Top |
- Robaszynski, F., more
- Donoso, J.M.G.
- Linares, D.
- Amedro, F.
- Caron, M.
- Dupuis, C.
- Dhondt, A.V.
- Gartner, S.
In Central Tunisia, the area between Kalaat Senan and Tajerouine shows a Coniacian to Maastrichtian succession of marls and limestones, 1300 metres thick, related to a sedimentation on a distal platform. The marry formations Kef p.p. and El Haria p.p. comprise between them the Abiod Formation mainly calcareous, almost 500 metres thick. Seven new members are proposed to subdivide the thick Abiod Formation: Assila (alternations, 21 metres), Haraoua (limestones, 68 metres), Mahdi (alternations, 20 metres), Akhdar (marls, 156 metres), Gourbeuj (alternations, 40 metres), Ncham (limestones, 161 metres) and Gouss (alternations, 22 metres).
The whole succession provided a rich palaeontological material which allows to establish vertical distribution charts thanks to numerous collectings of macrofossils and close sampling for microfossils( with a 1 to 6 metre-spacing as necessary).
About Ammonites, a lot of species are mentionned for the first time. Moreover, the following zones or intervals are identified: Prionocyclus germari, Barroisiceras cf. tunetanum, Para-and Protexanites, Texanites, Nostoceras (Bostrychoceras) polyplocum, N.(N.) hyatti, N.(N.) alternatum. Besides, nine ecoevents are demonstrated.
Seven Inoceramid species are determined, taking into account for the first time the international literature.
With regard to Foraminifera, 8 international planktonic zones and 15 regional zones are identified from washed samples as well as in thin sections and vertical distribution of about ten main Foraminifera bioevents is given. The microfacies show fluctuation of r and K species, probably linked to eustatic variations of the sea-level.
Relatively to the calcareous Nannofossils, the zones CC 13 to CC 26 considered to have a global value are all characterised.
The whole of biostratigraphic data supports the placement of the boundaries from Turonian up to Maastrichtian and a discussion is presented with a comparison to the recommendations given at the conclusions of the 1995 Brussels Symposium of the International sub-Commission on Cretaceous Stratigraphy.
The shortness of the Globotruncanita elevata foraminifera zone suggests a sedimentation with hiatus near the Santonian - Campanian boundary, underlined by a glauconitic and gravel level.