'Danian/Maastrichtian hiatus': A basin-wide event in the eastern Benin (Dahomey) Basin, Nigeria based on evidence from calcareous nannofossils

摘要

The calcareous nannofossil biostratigraphy of three wells (DB-1, DB-2 and DB-3) drilled along an approximate SWW-NEE trend in the eastern section of the Benin (Dahomey) Basin, Nigeria, has shown significant stratigraphic gaps in the sedimentary succession. In this study, we better constrained the presence and durations of four major hiatuses that occurred between the Late Cretaceous and late Miocene. Most conspicuous was an approximately 11.62 million-year hiatus spanning the Maastrichtian (Late Cretaceous, similar to 72.1 Ma) and Danian (Early Paleocene, similar to 60.48 Ma). The other unconformities identified occurred during the Eocene/Oligocene, Late Oligocene/early Miocene and middle/late Miocene. The presence of these unconformities across large areas of the basin is an indication of low sea levels and/or tilt in regional basin tectonics during the Late Cretaceous/Early Paleogene and has implication for stratigraphic trap styles for hydrocarbon exploration.