Albian bivalves from Madiela Formation in north Gabonese coastal basin

Benjamin Musavu Moussavou

doi:10.1051/bsgf/2019006

Abstract

A study of Albian bivalves from Madiela Formation in north of Gabonese coastal basin has been carried out from N’Toum quarry geological section. Four genera including six species are identified: Liopistha (Psilomya) sp. 1, ? Liopistha (Psilomya) sp. 2, Megaporomya sp., Neithea (Neithea) dutrugei (Coquand, 1862), Pleuromya sp. 1 and Pleuromya sp. 2. One morphotype is identified as Bivalvia gen. et sp. indet. The genus Megaporomya Ayoub-Hannaa et al., 2013 and all identified species, except Neithea (Neithea) dutrugei (Coquand, 1862), are found for the first time in Gabonese coastal basin. Now, a total of twelve species of bivalves have been reported from the Madiela Formation. In Gabon, the presence for the first time of genera Liopistha and Pleuromya in N’Toum quarry geological section which is assigned to the Albian permits us to expand their geographical distribution until N’Toum region, and their age range to Albian.

Highlights

The Gabonese coastal basin is one of the West Africa coastal basins which extend from Cameroon to Angola-Namibia and contains sediments with different geological stories
Prerift and rift phases are characterized mainly by continental, lacustrine and fluvial sediments whereas the drift phase is characterized by marine sediments
We describe species which are mentioned for the first time in the Albian of the Gabonese coastal basin

Summary

Introduction

The Gabonese coastal basin is one of the West Africa coastal basins which extend from Cameroon to Angola-Namibia and contains sediments with different geological stories. The tectonic and sedimentary evolution (Mbina Mounguengui, 1998; Mbina Mounguengui et al, 2002; Mbina Mounguengui and Lang, 2003) allow to recognize three phases: a prerift phase (PrecambrianJurassic), a rift phase (Neocomian-Barremian) and a drift phase (Aptian-present). Prerift and rift phases are characterized mainly by continental, lacustrine and fluvial sediments whereas the drift phase is characterized by marine sediments. There is the Madiela Formation (Albian) which occurs in N’Toum.

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