A revised chronostratigraphic framework for the Aptian of the Essaouira-Agadir Basin, a candidate type section for the NW African Atlantic Margin.

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 δ13Ccarb, δ13Corg, 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.

The influence of base-salt relief, rift topography and regional events on salt tectonics offshore Morocco

“…Despite the lack of proven reservoir-quality sediments in the Upper Cretaceous and Cenozoic targets, many regional elements point to the presence of turbiditic deepwater fans in the Lower Cretaceous and Middle Jurassic (Lancelot and Winterer, 1980;Tari et al, 2012). More recent studies also document the existence of fluvial feeder systems that could be the source for deepwater fans in the Lower Cretaceous (Luber et al, 2017;2019). Due to the long-lived and dynamic salt deformation (Hafid et al, 2000;Tari et al, 2003;Davison 2005), salt has acted as a strong control in the distribution of depocentres and sediment fairways across the slope and deep-basin, generating potential hydrocarbon traps and migration pathways.…”