Jornal de Geologia e Geofísica
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The "Yolde Formation", Upper Benue Trough, N.E. Nigeria-a Critical Look at its Existence

Amadu Tukur

This paper is intended to raise critical questions on the existence of the Yolde Formation as a lithologic unit in the stratigraphy of the Upper Benue Trough, N.E. Nigeria. Previous authors interpreted the formation as transitional. But how transitional is it? The discussion involved critical analysis of the type section and other identified sections of the formation. Careful appraisal of the previous works shows that both the definition and description of the type section of the formation do not agree. Lower and upper boundaries of the formation were not clearly defined as they did not identify major change in depositional episode. The formation as currently defined contained major shift from continental to marine paleoenvironments. The sediments of the so-call Yolde Formation should be carefully looked at so that it can be grouped properly into its rightful lithologic unit and interpreted with high level of certainty