Stratigraphic Status of the Bama Beach Ridge and the Chad Formation in the Bornu Sub-Basin, Nigeria

摘要

This work employed heavy mineral and micropalaeontological procedures to distinguish the Bama Beach Ridge from the Chad Formation in the Bornu sub-basin, Nigeria. Heavy mineral studies show the Bama Ridge samples as consisting of well diversified suite of both opaque and non opaque heavy minerals. These include Haematite, Magnetite, Leucoxene and Ilmenite on one hand and Zircon, tourmaline and rutile on the other. The Chad Formation, however, yielded only four species namely: zircon, rutile, apatite and sphene. Micropalaeontological analyses of several silty clay samples of the Bama Ridge yielded the ostracod species of Eucypris sp., Cypridopsis sp. and Darwinula sp. The Chad Formation samples are found to be effectively devoid of microfossil species. It is thus implied that the Bama Beach Ridge is a separate stratigraphic entity from the Quaternary Chad Formation in the Bornu sub-basin.