Abstract: The deep-water Léopard gas discovery in offshore Gabon presents an opportunity to examine distal facies of the Albian Madiela and Cap Lopez Groups, which overlie the Aptian Ezanga Salt. In proximal settings, the Madiela (Azingo Formation) consists of shallow marine limestone and has sparse foraminiferal recovery. In contrast, planktonic foraminifera assemblages are typically abundant and reasonably diverse in the interbedded calcareous claystones, marls, and limestones of the distal equivalent (Namina Formation) penetrated by the Léopard discovery and appraisal wells. Five informal local planktonic foraminiferal biozones are interpreted, listed from youngest to oldest, as follows: (1) an Early Cenomanian–Late Albian Muricohedbergella delrioensis “Partial-Range Zone,” characterized by abundant Muricohedbergella delrioensis and a diverse benthic foraminiferal assemblage; (2) a Late Albian Ticinella spp. “Highest-Occurrence Zone,” defined by top Ticinella primula and Globigerinelloides bentonensis ; (3) a Late–Middle Albian Favusella spp. “Highest-Occurrence Zone,” defined by the top of common Favusella washitensis and containing the additional top of Microhedbergella pseudoplanispira; (4) the Early Albian Microhedbergella rischi “Highest-Occurrence Zone,” defined by the top of Microhedbergella rischi and associated with increased numbers of spumellarian radiolaria; and (5) the earliest Albian Microhedbergella renilaevis “Taxon Range Zone,” defined by the top of Microhedbergella renilaevis . No conclusive Late Aptian microfossil markers were observed above the top of the halite (Ezanga) at Léopard, and the Aptian palynological marker, Exesipollenites tumulus , is not observed (in situ) until within the Ezanga. Organic carbon isotopes through the studied section show a positive excursion in the M. rischi and M. renilaevis zones, which broadly correlates to the OAE-1b set of Oceanic Anoxic Events (Urbino–Paquier–Kilian–Jacob).

Abstract In 2012, Beglinger et al . (2012a , b, and c) published a series of papers in which they systematically made analogous comparisons between the West African and Brazilian South Atlantic salt basins in order to identify new exploration opportunities. They believed that although every basin in the world is unique, they can still be classified according to their structural genesis and evolutionary history. This classification was based on breaking basins down into their tectonostratigraphic basin cycles or megasequences. By defining their characteristics with respect to the development of source, reservoir, and seal rocks, a data set of potential analogs can be compiled. This data set allowed for the identification of key combinations of elements and processes that resulted in an effective exploitable petroleum system, and assist in the evaluation of exploration opportunities in un- and under-explored basins ( Beglinger et al ., 2012a , b , and c ). Several tools can be used in such an analysis: the trajectory plot, tectonostratigraphies, the petroleum system flow diagram, events charts, creaming curves, field size distribution diagrams ( Beglinger et al ., 2012a , b , and c ), and areal field distribution maps. In this paper, the most recent exploration results in the Gabon Coastal basin will be reviewed in light of the framework that was established for the basin by Beglinger et al . (2012a , b ).