Paleocene Benthonic Foraminiferal Biostratigraphy, Biogeography and Paleoecology of Libya and Mali

Abstract

The Paleocene of Mali is developed along the inner shelf margin of a broad, shallow seaway which extended from Algeria to northern Nigeria. The Paleocene of Libya is developed in a structurally controlled embayment of the Tethys Sea which extended southwards through the Sirte Basin as far as the Chad border (Tibesti Mountains). The foraminiferal assemblages in Mali are dominated by shallow-water cibicidids, rotaliids, Rosalina, nonionids, Elphidiella, and various larger foraminifera, while planktonic foraminifera are rare or absent. The foraminiferal assemblages in Libya are developed in two lithotopes, one similar to that in Mali and containing numerous elements in common, the other, developed in a deeper-water basinal shale environment, containing a Midway type of fauna, together with planktonic foraminifera. Vertical and horizontal relationships between benthonic assemblages in the Sirte Basin are shown and paleoenvironmental reconstructions are made at approximately 2-million-year intervals. The Paleocene of Mali was deposited in a broad, shallow shelf sea at water depths probably less than 50 m. The Paleocene of the Sirte Basin of Libya was deposited in a transgressive sequence characterized by basin infilling at maximum depths somewhat in excess of 200 meters. Paleocene benthonic foraminiferal biostratigraphy, biogeography and paleoecology of Libya and Mali