Biostratigraphy of upper Cretaceous through Paleocene successions in Grombalia, Tunisia (southern Tethyan domain)-reworking processes and interpretations

Revision of Late Cretaceous through Paleocene planktic foraminiferal zonal schemes for northeastern Tunisia (Khanguet El Hajjej and Sidi Rhilaine section) has provided new insights into the biostratigraphic framework of the Abiod Formation. A late Paleocene age is endowed with this unit based on the occurrence of late Cretaceous reworked microfauna associated with Morozovella velascoensis planktic foraminifera. The biostratigraphic equivalent, between the mayaroensis and velascoensis Zones near J. Barka, includes an occasional submarine reworking of sediments induced by mass flow transport, indicated by the presence of microfaunal content and heterogeneous extraclasts. The internal organization of sediment (olistoliths, mass flow deposits) reflects tectonic activity and clear evidence of redeposition during the late Paleocene.