Cenomanian–Turonian ammonite successions in the Tinrhert Basin (Southeastern Algeria): Revision and new data

摘要

The Cenomanian–Turonian succession (C–T) outcropping in the Tinrhert Basin, in the southeastern part of Algeria, has been the focus of many studies since the turn of the 19th century. In the present research, new C–T sections have been scrutinized over a distance of approximately 300?km, from Gour Ben Houilet in the west to Oued In Adaoui in the east. More than 1.700 ammonites and nautilids were collected bed-by-bed and 30 taxa subsequently identified; these are systematically described and illustrated herein. Thirteen of them [Placenticerascf.kaffrariumEtheridge,Metengonoceras dumbli(Cragin),Calycoceras(Proeucalycoceras) sp.,Pseudaspidoceras pseudonodosoides(Choffat), Vascocerasaff. glabrum(Barber), Rubroceras burroenseCobban, Hook and Kennedy,Fagesia peroniPervinquière, Eotissotia simplexBarber, Hoplitoides wohltmanni(Von Koenen), Kamerunoceras turoniense(d'Orbigny), Choffaticerassp., Choffaticeras meslei(Peron), andChoffaticeras sinaiticumDouvillé] are recorded from the Tinrhert area for the first time. This study also evidences that both subspeciesNeolobites vibrayeanus vibrayeanus(d'Orbigny) andNeolobites vibrayeanus brancaiEck are associated in the same section and in the same level.In the Tinrhert area, the biostratigraphic ammonite successions are subdivided into nine bio-events that are easily correlatable with the upper Cenomanian–lower Turonian standard zonation. The paleobiogeographic affinities of the recorded taxa characterize these ammonoid assemblages as part of the southern Tethyan Province during the early Late Cretaceous.