Palynological Studies of Some Coaly Shales around Gamawa Kumo area, Gongola Basin, Northern Benue Trough, Nigeria

Abstract

Thirty (30) outcrop samples from a section at Gamawa area, Gongola basin, Northern Benue trough were palynologically analyzed to determine age, and paleo-depositional conditions of the strata. Lithological the section is composed of silts, clays and sandstone intercalations at the base followed by coaly shales and bioturbated silty to fine-grained sandstones at the top. Samples were treated with Hydrochloric and Hydrofluoric acids to remove carbonates and silicates respectively and slides were prepared using standard techniques. A total of 1250 palynomorph specimens were recovered. A palynological age of Upper Maastrichtian was assigned to this interval best on the assemblage of Maastrichtian diagnostic marker species of Longapertites marginatus, Proxaperties operculatus, Spinizonocolpites Baculatus, Monocolpites marginatus especially by the abundance of Pollen Spinizonocolpites Baculatus. Based on the low palynomorph marine index and dominating presence of Palme group species, especially the Spinizonocolpites Species the study suggested a paleodepositional condition of a mangrove forest with evidence of tidal dominated estuarine conditions in mostly brackishwater and a temperate climate.