Storm-dominated shallow marine trace fossils of the Lower Devonian Teferguenite Formation (Saoura valley, Algeria)

Mohamed Bendella ¹, Madani Benyoucef ², Radek Mikuláš ³, Imad Bouchemla ¹ & Bruno Ferré ^4
1Mohamed Ben Ahmed Oran 2 University, Laboratory of Basin Geodynamics and Sedimentary Balance, P.O. Box 1524, El M’Naouer, DZ-31000 Oran, Algeria., ²Faculty of Natural and Life Sciences, University Mustapha Stambouli of Mascara, DZ-29000 Mascara, Algeria., ³Institute of Geology of the Czech Academy of Sciences, Rozvojová 269, CZ-165 02 Praha 6, Czech Republic., ⁴2 rue Guy de Maupassant, F-76800 Saint Étienne du Rouvray, France.

The mixed siliciclastic-carbonate Teferguenite Formation (Pragian-Emsian) occurring in the Ougarta Range (SW Algeria) is subdivided into two members: the Lower Member consists of three thick limestone beds (namely bars) intercalated with clay and sandstone deposits; the Upper Member is composed of intercalated sandstone, silty limestone and clay. Sedimentological data and their associated ichnological content were used for the interpretation of depositional settings. Lithofacies analysis evidenced that the studied succession was deposited in a shallow marine (shoreface to upper offshore), storm-influenced setting. Ichnological data document moderate to high bioturbation intensity, while ichnodiversity consists of 29 ichnospecies, namely: Arenicolites isp., Arthraria antiquata, Arthrophycus isp., Bergaueria perata, Bolonia lata, Chondrites targionii, Cochlichnus anguineus, cf. Cruziana isp., Cruziana rusoformis, Diplichnites isp., Gordia marina, Helminthopsis abeli, Hormosiroidea isp., Lockeia siliquaria, Megagrapton irregulare, Monomorphichnus cf. multilineatus, Neonereites uniserialis, N. multiserialis, Nereites isp., Phycodes isp., Protovirgularia isp., Rusophycus isp., Thalassinoides isp., T. suevicus, Palaeophycus isp., P. striatus, P. tubularis, and Zoophycos ispp. (types A and B). These trace fossils are gathered in three trace-fossil assemblages: the Palaeophycus-Thalassinoides-Arenicolites ichnoassemblage (PTAI), the Cruziana-Thalassinoides ichnoassemblage (CTI) and the Neonereites-Zoophycos ichnoassemblage (NZI). The trace-fossil records within the Teferguenite Formation is represented by different behaviours, corresponding to the archetypal Cruziana ichnofacies occurring from the shoreface to upper offshore zones.