A revised chronostratigraphic framework for the Aptian of the Essaouira-Agadir Basin, a candidate type section for the NW African Atlantic Margin. (January 2019) - Luber, Tim L.
Abstract: The Essaouira-Agadir Basin (EAB) of Morocco contains the most extensive exposure of Aptian to Lower Albian strata onshore the NW African Atlantic Margin. This paper documents the first high-resolution, multi-disciplinary stratigraphic approach for the Aptian to Lower Albian on the NW African Atlantic Margin. Previous biostratigraphic work almost exclusively relied on long-distance correlation of ammonoids to the Mediterranean – Caucasian Realm. Recent biostratigraphic work has questioned some of the previous interpretations, highlighting significant faunal endemism and complications with correlation to other key Aptian sections. This study focuses on 5 key sections: Tiskatine, Id Amran, Assaka, and DSDP 416/370. Distribution of ammonoids, foraminifera, and calcareous nannofossils are reported from a bed-by-bed collection made at Tiskatine. The analysis of foraminiferal and calcareous nannofossil assemblages enable correlation to standard zonation schemes; but also highlights the urgent need of revision and future work on the integration of these schemes across disciplines. The study, further, includes δ 13 Ccarb, δ 13 Corg, and total organic carbon (TOC) data that is compared to reference material from the Vocontian Basin. The combined litho-, bio-, chemo-, and sequence stratigraphic analysis establishes a robust chronostratigraphic framework for regional and super-regional correlations and a type section is proposed for the Aptian of NW Africa at Tiskatine.